Science.gov

Sample records for pressure relief valve

  1. Glovebox pressure relief and check valve

    SciTech Connect

    Blaedel, K.L.

    1986-03-17

    This device is a combined pressure relief valve and check valve providing overpressure protection and preventing back flow into an inert atmosphere enclosure. The pressure relief is embodied by a submerged vent line in a mercury reservior, the releif pressure being a function of the submerged depth. The pressure relief can be vented into an exhaust system and the relieving pressure is only slightly influenced by the varying pressure in the exhaust system. The check valve is embodied by a ball which floats on the mercury column and contacts a seat whenever vacuum exists within the glovebox enclosure. Alternatively, the check valve is embodied by a vertical column of mercury, the maximum back pressure being a function of the height of the column of mercury.

  2. 46 CFR 154.806 - Capacity of pressure relief valves.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Capacity of pressure relief valves. 154.806 Section 154... Equipment Cargo Vent Systems § 154.806 Capacity of pressure relief valves. Pressure relief valves for each cargo tank must have a combined relief capacity, including the effects of back pressure from vent...

  3. 46 CFR 154.806 - Capacity of pressure relief valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Capacity of pressure relief valves. 154.806 Section 154... Equipment Cargo Vent Systems § 154.806 Capacity of pressure relief valves. Pressure relief valves for each cargo tank must have a combined relief capacity, including the effects of back pressure from vent...

  4. 46 CFR 154.806 - Capacity of pressure relief valves.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Capacity of pressure relief valves. 154.806 Section 154... Equipment Cargo Vent Systems § 154.806 Capacity of pressure relief valves. Pressure relief valves for each cargo tank must have a combined relief capacity, including the effects of back pressure from vent...

  5. 46 CFR 154.806 - Capacity of pressure relief valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Capacity of pressure relief valves. 154.806 Section 154... Equipment Cargo Vent Systems § 154.806 Capacity of pressure relief valves. Pressure relief valves for each cargo tank must have a combined relief capacity, including the effects of back pressure from vent...

  6. 46 CFR 154.806 - Capacity of pressure relief valves.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Capacity of pressure relief valves. 154.806 Section 154... Equipment Cargo Vent Systems § 154.806 Capacity of pressure relief valves. Pressure relief valves for each cargo tank must have a combined relief capacity, including the effects of back pressure from vent...

  7. 46 CFR 154.1846 - Relief valves: Changing set pressure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Relief valves: Changing set pressure. 154.1846 Section... Relief valves: Changing set pressure. The master shall: (a) Supervise the changing of the set pressure of relief valves under § 154.802(b); (b) Enter the change of set pressure in the vessel's log; and...

  8. 46 CFR 154.1846 - Relief valves: Changing set pressure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Relief valves: Changing set pressure. 154.1846 Section... Relief valves: Changing set pressure. The master shall: (a) Supervise the changing of the set pressure of relief valves under § 154.802(b); (b) Enter the change of set pressure in the vessel's log; and...

  9. 46 CFR 154.1846 - Relief valves: Changing set pressure.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Relief valves: Changing set pressure. 154.1846 Section... Relief valves: Changing set pressure. The master shall: (a) Supervise the changing of the set pressure of relief valves under § 154.802(b); (b) Enter the change of set pressure in the vessel's log; and...

  10. 46 CFR 154.1846 - Relief valves: Changing set pressure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Relief valves: Changing set pressure. 154.1846 Section... Relief valves: Changing set pressure. The master shall: (a) Supervise the changing of the set pressure of relief valves under § 154.802(b); (b) Enter the change of set pressure in the vessel's log; and...

  11. 46 CFR 154.1846 - Relief valves: Changing set pressure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Relief valves: Changing set pressure. 154.1846 Section... Relief valves: Changing set pressure. The master shall: (a) Supervise the changing of the set pressure of relief valves under § 154.802(b); (b) Enter the change of set pressure in the vessel's log; and...

  12. 46 CFR 105.10-20 - Pressure vacuum relief valve.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in...

  13. 46 CFR 105.10-20 - Pressure vacuum relief valve.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in...

  14. 46 CFR 105.10-20 - Pressure vacuum relief valve.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in...

  15. 46 CFR 105.10-20 - Pressure vacuum relief valve.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in...

  16. 46 CFR 105.10-20 - Pressure vacuum relief valve.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Pressure vacuum relief valve. 105.10-20 Section 105.10... Pressure vacuum relief valve. (a) The term pressure vacuum relief valve means any device or assembly of a mechanical, liquid, weight, or other type used for the automatic regulation of pressure or vacuum in...

  17. Statistical Performance Evaluation Of Soft Seat Pressure Relief Valves

    SciTech Connect

    Harris, Stephen P.; Gross, Robert E.

    2013-03-26

    Risk-based inspection methods enable estimation of the probability of failure on demand for spring-operated pressure relief valves at the United States Department of Energy's Savannah River Site in Aiken, South Carolina. This paper presents a statistical performance evaluation of soft seat spring operated pressure relief valves. These pressure relief valves are typically smaller and of lower cost than hard seat (metal to metal) pressure relief valves and can provide substantial cost savings in fluid service applications (air, gas, liquid, and steam) providing that probability of failure on demand (the probability that the pressure relief valve fails to perform its intended safety function during a potentially dangerous over pressurization) is at least as good as that for hard seat valves. The research in this paper shows that the proportion of soft seat spring operated pressure relief valves failing is the same or less than that of hard seat valves, and that for failed valves, soft seat valves typically have failure ratios of proof test pressure to set pressure less than that of hard seat valves.

  18. 46 CFR 64.59 - Spring loaded pressure relief valve.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Spring loaded pressure relief valve. 64.59 Section 64.59 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.59...

  19. 46 CFR 64.59 - Spring loaded pressure relief valve.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Spring loaded pressure relief valve. 64.59 Section 64.59 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.59...

  20. 46 CFR 64.59 - Spring loaded pressure relief valve.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Spring loaded pressure relief valve. 64.59 Section 64.59 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.59...

  1. 46 CFR 64.59 - Spring loaded pressure relief valve.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Spring loaded pressure relief valve. 64.59 Section 64.59 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.59...

  2. 46 CFR 64.59 - Spring loaded pressure relief valve.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Spring loaded pressure relief valve. 64.59 Section 64.59 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.59...

  3. 49 CFR 179.220-24 - Tests of pressure relief valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Tests of pressure relief valves. 179.220-24... FOR TANK CARS Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.220-24 Tests of pressure relief valves. Each safety relief valve must be tested by air or gas...

  4. 49 CFR 179.220-24 - Tests of pressure relief valves.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Tests of pressure relief valves. 179.220-24... CARS Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.220-24 Tests of pressure relief valves. Each safety relief valve must be tested by air or gas for compliance with §...

  5. 46 CFR 30.10-55 - Pressure vacuum relief valve-TB/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Pressure vacuum relief valve-TB/ALL. 30.10-55 Section 30... Definitions § 30.10-55 Pressure vacuum relief valve—TB/ALL. The term pressure vacuum relief valve means any... pressure or vacuum in enclosed places....

  6. 46 CFR 30.10-55 - Pressure vacuum relief valve-TB/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Pressure vacuum relief valve-TB/ALL. 30.10-55 Section 30... Definitions § 30.10-55 Pressure vacuum relief valve—TB/ALL. The term pressure vacuum relief valve means any... pressure or vacuum in enclosed places....

  7. 46 CFR 30.10-55 - Pressure vacuum relief valve-TB/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Pressure vacuum relief valve-TB/ALL. 30.10-55 Section 30... Definitions § 30.10-55 Pressure vacuum relief valve—TB/ALL. The term pressure vacuum relief valve means any... pressure or vacuum in enclosed places....

  8. 46 CFR 30.10-55 - Pressure vacuum relief valve-TB/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Pressure vacuum relief valve-TB/ALL. 30.10-55 Section 30... Definitions § 30.10-55 Pressure vacuum relief valve—TB/ALL. The term pressure vacuum relief valve means any... pressure or vacuum in enclosed places....

  9. 46 CFR 30.10-55 - Pressure vacuum relief valve-TB/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Pressure vacuum relief valve-TB/ALL. 30.10-55 Section 30... Definitions § 30.10-55 Pressure vacuum relief valve—TB/ALL. The term pressure vacuum relief valve means any... pressure or vacuum in enclosed places....

  10. 49 CFR 179.200-23 - Tests of pressure relief valves.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Tests of pressure relief valves. 179.200-23... CARS Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.200-23 Tests of pressure relief valves. (a) Each valve shall be tested by air or gas for compliance with § 179.15...

  11. 46 CFR 32.20-5 - Pressure vacuum relief valves-TB/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Pressure vacuum relief valves-TB/ALL. 32.20-5 Section 32..., AND HULL REQUIREMENTS Equipment Installations § 32.20-5 Pressure vacuum relief valves—TB/ALL. The pressure vacuum relief valve shall be of a type and size approved by the Commandant for the...

  12. 46 CFR 32.20-5 - Pressure vacuum relief valves-TB/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Pressure vacuum relief valves-TB/ALL. 32.20-5 Section 32..., AND HULL REQUIREMENTS Equipment Installations § 32.20-5 Pressure vacuum relief valves—TB/ALL. The pressure vacuum relief valve shall be of a type and size approved by the Commandant for the...

  13. 46 CFR 32.20-5 - Pressure vacuum relief valves-TB/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Pressure vacuum relief valves-TB/ALL. 32.20-5 Section 32..., AND HULL REQUIREMENTS Equipment Installations § 32.20-5 Pressure vacuum relief valves—TB/ALL. The pressure vacuum relief valve shall be of a type and size approved by the Commandant for the...

  14. 46 CFR 32.20-5 - Pressure vacuum relief valves-TB/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Pressure vacuum relief valves-TB/ALL. 32.20-5 Section 32..., AND HULL REQUIREMENTS Equipment Installations § 32.20-5 Pressure vacuum relief valves—TB/ALL. The pressure vacuum relief valve shall be of a type and size approved by the Commandant for the...

  15. 46 CFR 32.20-5 - Pressure vacuum relief valves-TB/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Pressure vacuum relief valves-TB/ALL. 32.20-5 Section 32..., AND HULL REQUIREMENTS Equipment Installations § 32.20-5 Pressure vacuum relief valves—TB/ALL. The pressure vacuum relief valve shall be of a type and size approved by the Commandant for the...

  16. 49 CFR 179.200-23 - Tests of pressure relief valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... FOR TANK CARS Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.200-23 Tests of pressure relief valves. (a) Each valve shall be tested by air or gas for compliance...

  17. 49 CFR 179.400-21 - Test of pressure relief valves.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Test of pressure relief valves. 179.400-21 Section 179.400-21 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND... 107A) § 179.400-21 Test of pressure relief valves. Each valve must be tested with air or gas...

  18. 49 CFR 179.400-21 - Test of pressure relief valves.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... CARS Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.400-21 Test of pressure relief valves. Each valve must be tested with air or gas...

  19. 49 CFR 179.400-21 - Test of pressure relief valves.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... CARS Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.400-21 Test of pressure relief valves. Each valve must be tested with air or gas...

  20. 49 CFR 179.400-21 - Test of pressure relief valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... FOR TANK CARS Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.400-21 Test of pressure relief valves. Each valve must be tested with air or...

  1. 49 CFR 179.400-21 - Test of pressure relief valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... CARS Specification for Cryogenic Liquid Tank Car Tanks and Seamless Steel Tanks (Classes DOT-113 and 107A) § 179.400-21 Test of pressure relief valves. Each valve must be tested with air or gas...

  2. 77 FR 59408 - Finding of Equivalence; Alternate Pressure Relief Valve Settings on Certain Vessels Carrying...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-27

    ...] Finding of Equivalence; Alternate Pressure Relief Valve Settings on Certain Vessels Carrying Liquefied... announces the availability of CG-ENG Policy Letter 04-12, ``Alternative Pressure Relief Valve Settings on... Society of Mechanical Engineers (ASME) Boiler and Pressure Vessel Code (BPVC) Section VIII with respect...

  3. 49 CFR 179.220-24 - Tests of pressure relief valves.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... CARS Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.220-24 Tests of pressure relief valves. Each safety relief valve must be tested by air or gas for compliance with §...

  4. 49 CFR 179.220-24 - Tests of pressure relief valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... CARS Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.220-24 Tests of pressure relief valves. Each safety relief valve must be tested by air or gas for compliance with §...

  5. 49 CFR 179.220-24 - Tests of pressure relief valves.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... CARS Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.220-24 Tests of pressure relief valves. Each safety relief valve must be tested by air or gas for compliance with §...

  6. Fluid relief and check valve

    DOEpatents

    Blaedel, K.L.; Lord, S.C.; Murray, I.

    1986-07-17

    A passive fluid pressure relief and check valve allows the relief pressure to be slaved to a reference pressure independently of the exhaust pressure. The pressure relief valve is embodied by a submerged vent line in a sealing fluid, the relief pressure being a function of the submerged depth. A check valve is embodied by a vertical column of fluid (the maximum back pressure being a function of the height of the column of fluid). The pressure is vented into an exhaust system which keeps the exhaust out of the area providing the reference pressure.

  7. 49 CFR 179.200-23 - Tests of pressure relief valves.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... CARS Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.200-23 Tests of pressure relief valves. (a) Each valve shall be tested by air or gas for compliance with § 179.15...

  8. 49 CFR 179.200-23 - Tests of pressure relief valves.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... CARS Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.200-23 Tests of pressure relief valves. (a) Each valve shall be tested by air or gas for compliance with § 179.15...

  9. 49 CFR 179.200-23 - Tests of pressure relief valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... CARS Specifications for Non-Pressure Tank Car Tanks (Classes DOT-111AW and 115AW) § 179.200-23 Tests of pressure relief valves. (a) Each valve shall be tested by air or gas for compliance with § 179.15...

  10. Liquid rocket pressure regulators, relief valves, check valves, burst disks, and explosive valves. [design techniques and practices

    NASA Technical Reports Server (NTRS)

    1973-01-01

    The development of and operational programs for effective use in design are presented for liquid rocket pressure regulators, relief valves, check valves, burst disks, and explosive valves. A review of the total design problem is presented, and design elements are identified which are involved in successful design. Current technology pertaining to these elements is also described. Design criteria are presented which state what rule or standard must be imposed on each essential design element to assure successful design. These criteria serve as a checklist of rules for a project manager to use in guiding a design or in assessing its adequacy. Recommended practices are included which state how to satisfy each of the criteria.

  11. Analysis of HFIR pressurizer pump overspeed transients and relief valve performance

    SciTech Connect

    Sozer, M.C.

    1992-09-11

    The pressurizer pump overspeed transients at the High Flux Isotope Reactor (HFIR) fall in the category of {open_quotes}increase in coolant inventory transients.{close_quotes} They are among the accident transients to be performed for Chapter 15 of the HFIR safety analysis report (SAR). The pressurizer pump speed starting to increase inadvertently to reach its maximum speed of 3,560 rpm while the reactor operates under normal conditions is the cause of this transient. Increased primary coolant system pressure due to increased pressurizer pump flow into the primary coolant head tank challenges the relief valves to open. If the relief valves do not open, increased primary coolant system pressure will challenge the integrity of the high pressure boundary. Two sets of analyses were performed to analyze the pressurizer pump overspeed transients. The purpose of the first analysis is to estimate how long it will take for the relief valves to open under different conditions and whether or not they will chatter or flutter for a considerable amount of time. The analysis estimates relief valve performance and stability using four different relief valve subsystem models. The relief valve subsystem models are not attached to the primary coolant system model. Vigorous pressure oscillations were produced in all of the computations performed as part of the first analysis. The second analysis includes new simulations of the pressurizer pump overspeed transients that were previously simulated using the RELAP5 thermal-hydraulic computer code. The HFIRSYS, High Flux Isotope Reactor System Transient Analysis computer code, was utilized for these simulations providing referable results for comparisons. The increased pressurizer pump flow due to runaway pressurizer pump speed pressurizes the primary coolant system. The assumptions were made in such a way to form constraining conditions at initiation of and during the transients to generate as high an overpressure situation as possible.

  12. Navier-Stokes Flow Field Analysis of Compressible Flow in a Pressure Relief Valve

    NASA Technical Reports Server (NTRS)

    Vu, Bruce T.; Wang, Ten-See; Shih, Ming-Hsin; Soni, Bharat K.

    1993-01-01

    The present study was motivated to analyze the complex flow field involving gaseous oxygen (GOX) flow in a relief valve (RV). The 9391 RV, pictured in Figure 1, was combined with the pilot valve to regulate the actuation pressure of the main valve system. During a high-pressure flow test at Marshall Space Flight Center (MSFC) the valve system developed a resonance chatter, which destroyed most of the valve body. Figures 2-4 show the valve body before and after accident. It was understood that the subject RV has never been operated at 5500 psia. In order to fully understand the flow behavior in the RV, a computational fluid dynamics (CFD) analysis is carried out to investigate the side load across the piston sleeve and the erosion patterns resulting from flow distribution around piston/nozzle interface.

  13. 40 CFR 65.110 - Standards: Pumps, valves, connectors, and agitators in heavy liquid service; pressure relief...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., and agitators in heavy liquid service; pressure relief devices in liquid service; and instrumentation..., connectors, and agitators in heavy liquid service; pressure relief devices in liquid service; and..., valves, connectors, and agitators in heavy liquid service; pressure relief devices in light liquid...

  14. 40 CFR 65.110 - Standards: Pumps, valves, connectors, and agitators in heavy liquid service; pressure relief...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., and agitators in heavy liquid service; pressure relief devices in liquid service; and instrumentation..., connectors, and agitators in heavy liquid service; pressure relief devices in liquid service; and..., valves, connectors, and agitators in heavy liquid service; pressure relief devices in light liquid...

  15. 40 CFR 65.110 - Standards: Pumps, valves, connectors, and agitators in heavy liquid service; pressure relief...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., and agitators in heavy liquid service; pressure relief devices in liquid service; and instrumentation..., connectors, and agitators in heavy liquid service; pressure relief devices in liquid service; and..., valves, connectors, and agitators in heavy liquid service; pressure relief devices in light liquid...

  16. 40 CFR 65.110 - Standards: Pumps, valves, connectors, and agitators in heavy liquid service; pressure relief...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., and agitators in heavy liquid service; pressure relief devices in liquid service; and instrumentation..., connectors, and agitators in heavy liquid service; pressure relief devices in liquid service; and..., valves, connectors, and agitators in heavy liquid service; pressure relief devices in light liquid...

  17. 40 CFR 65.110 - Standards: Pumps, valves, connectors, and agitators in heavy liquid service; pressure relief...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., and agitators in heavy liquid service; pressure relief devices in liquid service; and instrumentation..., connectors, and agitators in heavy liquid service; pressure relief devices in liquid service; and..., valves, connectors, and agitators in heavy liquid service; pressure relief devices in light liquid...

  18. Aspirator increases relief valve poppet stroke

    NASA Technical Reports Server (NTRS)

    Biddle, M. E.

    1967-01-01

    Addition of an aspirator to a relief valve increases the valve poppet stroke under dynamic flow conditions. The aspirator allows poppet inlet dynamic forces to overcome relief valve spring force. It reduces the fluid pressure in the skirt cavity by providing a low pressure sense probe.

  19. 40 CFR 63.1010 - Pumps, valves, connectors, and agitators in heavy liquid service; pressure relief devices in...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... agitators in heavy liquid service; pressure relief devices in liquid service; and instrumentation systems..., connectors, and agitators in heavy liquid service; pressure relief devices in liquid service; and... comply with paragraphs (b)(1) and (b)(2) of this section. Pumps, valves, connectors, and agitators...

  20. 40 CFR 63.1029 - Pumps, valves, connectors, and agitators in heavy liquid service; pressure relief devices in...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... agitators in heavy liquid service; pressure relief devices in liquid service; and instrumentation systems..., connectors, and agitators in heavy liquid service; pressure relief devices in liquid service; and... shall comply with paragraphs (b)(1) and (b)(2) of this section. Pumps, valves, connectors, and...

  1. 40 CFR 63.1010 - Pumps, valves, connectors, and agitators in heavy liquid service; pressure relief devices in...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... agitators in heavy liquid service; pressure relief devices in liquid service; and instrumentation systems..., connectors, and agitators in heavy liquid service; pressure relief devices in liquid service; and... comply with paragraphs (b)(1) and (b)(2) of this section. Pumps, valves, connectors, and agitators...

  2. 40 CFR 63.1029 - Pumps, valves, connectors, and agitators in heavy liquid service; pressure relief devices in...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... agitators in heavy liquid service; pressure relief devices in liquid service; and instrumentation systems..., connectors, and agitators in heavy liquid service; pressure relief devices in liquid service; and... shall comply with paragraphs (b)(1) and (b)(2) of this section. Pumps, valves, connectors, and...

  3. 40 CFR 63.1029 - Pumps, valves, connectors, and agitators in heavy liquid service; pressure relief devices in...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... agitators in heavy liquid service; pressure relief devices in liquid service; and instrumentation systems..., connectors, and agitators in heavy liquid service; pressure relief devices in liquid service; and... shall comply with paragraphs (b)(1) and (b)(2) of this section. Pumps, valves, connectors, and...

  4. 40 CFR 63.1010 - Pumps, valves, connectors, and agitators in heavy liquid service; pressure relief devices in...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... agitators in heavy liquid service; pressure relief devices in liquid service; and instrumentation systems..., connectors, and agitators in heavy liquid service; pressure relief devices in liquid service; and... comply with paragraphs (b)(1) and (b)(2) of this section. Pumps, valves, connectors, and agitators...

  5. 40 CFR 63.1029 - Pumps, valves, connectors, and agitators in heavy liquid service; pressure relief devices in...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... agitators in heavy liquid service; pressure relief devices in liquid service; and instrumentation systems..., connectors, and agitators in heavy liquid service; pressure relief devices in liquid service; and... shall comply with paragraphs (b)(1) and (b)(2) of this section. Pumps, valves, connectors, and...

  6. 40 CFR 63.1029 - Pumps, valves, connectors, and agitators in heavy liquid service; pressure relief devices in...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... agitators in heavy liquid service; pressure relief devices in liquid service; and instrumentation systems..., connectors, and agitators in heavy liquid service; pressure relief devices in liquid service; and... shall comply with paragraphs (b)(1) and (b)(2) of this section. Pumps, valves, connectors, and...

  7. 40 CFR 63.1010 - Pumps, valves, connectors, and agitators in heavy liquid service; pressure relief devices in...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... agitators in heavy liquid service; pressure relief devices in liquid service; and instrumentation systems..., connectors, and agitators in heavy liquid service; pressure relief devices in liquid service; and... comply with paragraphs (b)(1) and (b)(2) of this section. Pumps, valves, connectors, and agitators...

  8. 40 CFR 63.1010 - Pumps, valves, connectors, and agitators in heavy liquid service; pressure relief devices in...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... agitators in heavy liquid service; pressure relief devices in liquid service; and instrumentation systems..., connectors, and agitators in heavy liquid service; pressure relief devices in liquid service; and... comply with paragraphs (b)(1) and (b)(2) of this section. Pumps, valves, connectors, and agitators...

  9. Investigation Of Adhesion Formation In New Stainless Steel Trim Spring Operated Pressure Relief Valves

    SciTech Connect

    Gross, Robert E.; Bukowski, Julia V.; Goble, William M.

    2013-04-16

    Examination of proof test data for new (not previously installed) stainless steel (SS) trim spring operated pressure relief valves (SOPRV) reveals that adhesions form between the seat and disc in about 46% of all such SOPRV. The forces needed to overcome these adhesions can be sufficiently large to cause the SOPRV to fail its proof test (FPT) prior to installation. Furthermore, a significant percentage of SOPRV which are found to FPT are also found to ''fail to open'' (FTO) meaning they would not relief excess pressure in the event of an overpressure event. The cases where adhesions result in FTO or FPT appear to be confined to SOPRV with diameters < 1 in and set pressures < 150 psig and the FTO are estimated to occur in 0.31% to 2.00% of this subpopulation of SS trim SOPRV. The reliability and safety implications of these finding for end-users who do not perform pre-installation testing of SOPRV are discussed.

  10. 40 CFR 60.482-8 - Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... liquid service, pressure relief devices in light liquid or heavy liquid service, and connectors. 60.482-8... Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or heavy liquid... any other detection method at pumps and valves in heavy liquid service, pressure relief devices...

  11. 40 CFR 60.482-8 - Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... liquid service, pressure relief devices in light liquid or heavy liquid service, and connectors. 60.482-8... Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or heavy liquid... any other detection method at pumps and valves in heavy liquid service, pressure relief devices...

  12. 40 CFR 60.482-8 - Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... liquid service, pressure relief devices in light liquid or heavy liquid service, and connectors. 60.482-8... Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or heavy liquid... any other detection method at pumps and valves in heavy liquid service, pressure relief devices...

  13. 40 CFR 60.482-8 - Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... liquid service, pressure relief devices in light liquid or heavy liquid service, and connectors. 60.482-8... Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or heavy liquid... any other detection method at pumps and valves in heavy liquid service, pressure relief devices...

  14. 40 CFR 60.482-8 - Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... liquid service, pressure relief devices in light liquid or heavy liquid service, and connectors. 60.482-8... Standards: Pumps and valves in heavy liquid service, pressure relief devices in light liquid or heavy liquid... any other detection method at pumps and valves in heavy liquid service, pressure relief devices...

  15. Helium pressures in RHIC vacuum cryostats and relief valve requirements from magnet cooling line failure

    SciTech Connect

    Liaw, C.J.; Than, Y.; Tuozzolo, J.

    2011-03-28

    A catastrophic failure of the RHIC magnet cooling lines, similar to the LHC superconducting bus failure incident, would pressurize the insulating vacuum in the magnet and transfer line cryostats. Insufficient relief valves on the cryostats could cause a structural failure. A SINDA/FLUINT{reg_sign} model, which simulated the 4.5K/4 atm helium flowing through the magnet cooling system distribution lines, then through a line break into the vacuum cryostat and discharging via the reliefs into the RHIC tunnel, had been developed to calculate the helium pressure inside the cryostat. Arc flash energy deposition and heat load from the ambient temperature cryostat surfaces were included in the simulations. Three typical areas: the sextant arc, the Triplet/DX/D0 magnets, and the injection area, had been analyzed. Existing relief valve sizes were reviewed to make sure that the maximum stresses, caused by the calculated maximum pressures inside the cryostats, did not exceed the allowable stresses, based on the ASME Code B31.3 and ANSYS results. The conclusions are as follows: (1) The S/F simulation results show that the highest internal pressure in the cryostats, due to the magnet line failure, is {approx}37 psig (255115 Pa); (2) Based on the simulation, the temperature on the cryostat chamber, INJ Q8-Q9, could drop to 228 K, which is lower than the material minimum design temperature allowed by the Code; (3) Based on the ASME Code and ANSYS results, the reliefs on all the cryostats inside the RHIC tunnel are adequate to protect the vacuum chambers when the magnet cooling lines fail; and (4) In addition to the pressure loading, the thermal deformations, due to the temperature decrease on the cryostat chambers, could also cause a high stress on the chamber, if not properly supported.

  16. Pressure Relief Devices

    NASA Astrophysics Data System (ADS)

    Manha, William D.

    2010-09-01

    Pressure relief devices are used in pressure systems and on pressure vessels to prevent catastrophic rupture or explosion from excessive pressure. Pressure systems and pressure vessels have manufacturers maximum rated operating pressures or maximum design pressures(MDP) for which there are relatively high safety factors and minimum risk of rupture or explosion. Pressure systems and pressure vessels that have a potential to exceed the MDP by being connected to another higher pressure source, a compressor, or heat to water(boiler) are required to have over-pressure protecting devices. Such devices can be relief valves and/or burst discs to safely relieve potentially excessive pressure and prevent unacceptable ruptures and explosions which result in fail-safe pressure systems and pressure vessels. Common aerospace relief valve and burst disc requirements and standards will be presented. This will include the NASA PSRP Interpretation Letter TA-88-074 Fault Tolerance of Systems Using Specially Certified Burst Disks that dictates burst disc requirements for payloads on Shuttle. Two recent undesirable manned space payloads pressure relief devices and practices will be discussed, as well as why these practices should not be continued. One example for discussion is the use of three burst discs that have been placed in series to comply with safety requirements of three controls to prevent a catastrophic hazard of the over-pressurization and rupture of pressure system and/or vessels. The cavities between the burst discs are evacuated and are the reference pressures for activating the two upstream burst discs. If the upstream burst disc leaks into the reference cavity, the reference pressure increases and it can increase the burst disc activating pressure and potentially result in the burst disc assembly being ineffective for over pressure protection. The three burst discs-in-series assembly was found acceptable because the burst discs are designed for minimum risk(DFMR) of

  17. Hydrogen gas relief valve

    DOEpatents

    Whittlesey, Curtis C.

    1985-01-01

    An improved battery stack design for an electrochemical system having at least one cell from which a gas is generated and an electrolyte in communication with the cell is described. The improved battery stack design features means for defining a substantially closed compartment for containing the battery cells and at least a portion of the electrolyte for the system, and means in association with the compartment means for selectively venting gas from the interior of the compartment means in response to the level of the electrolyte within the compartment means. The venting means includes a relief valve having a float member which is actuated in response to the level of the electrolyte within the compartment means. This float member is adapted to close the relief valve when the level of the electrolyte is above a predetermined level and open the relief valve when the level of electrolyte is below this predetermined level.

  18. 49 CFR 178.338-8 - Pressure relief devices, piping, valves, and fittings.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS... other pressure parts, except for pump seals and pressure relief devices, must be at least 4 times...

  19. 40 CFR 60.482-8a - Standards: Pumps, valves, and connectors in heavy liquid service and pressure relief devices in...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... connectors in heavy liquid service and pressure relief devices in light liquid or heavy liquid service. 60... connectors in heavy liquid service and pressure relief devices in light liquid or heavy liquid service. (a... at pumps, valves, and connectors in heavy liquid service and pressure relief devices in light...

  20. 40 CFR 60.482-8a - Standards: Pumps, valves, and connectors in heavy liquid service and pressure relief devices in...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... connectors in heavy liquid service and pressure relief devices in light liquid or heavy liquid service. 60... connectors in heavy liquid service and pressure relief devices in light liquid or heavy liquid service. (a... at pumps, valves, and connectors in heavy liquid service and pressure relief devices in light...

  1. 40 CFR 60.482-8a - Standards: Pumps, valves, and connectors in heavy liquid service and pressure relief devices in...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... connectors in heavy liquid service and pressure relief devices in light liquid or heavy liquid service. 60... connectors in heavy liquid service and pressure relief devices in light liquid or heavy liquid service. (a... at pumps, valves, and connectors in heavy liquid service and pressure relief devices in light...

  2. 40 CFR 60.482-8a - Standards: Pumps, valves, and connectors in heavy liquid service and pressure relief devices in...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... connectors in heavy liquid service and pressure relief devices in light liquid or heavy liquid service. 60... connectors in heavy liquid service and pressure relief devices in light liquid or heavy liquid service. (a... at pumps, valves, and connectors in heavy liquid service and pressure relief devices in light...

  3. 40 CFR 60.482-8a - Standards: Pumps, valves, and connectors in heavy liquid service and pressure relief devices in...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... connectors in heavy liquid service and pressure relief devices in light liquid or heavy liquid service. 60... connectors in heavy liquid service and pressure relief devices in light liquid or heavy liquid service. (a... at pumps, valves, and connectors in heavy liquid service and pressure relief devices in light...

  4. THE EFFECTS OF MAINTENANCE ACTIONS ON THE PFDavg OF SPRING OPERATED PRESSURE RELIEF VALVES

    SciTech Connect

    Harris, S.; Gross, R.

    2014-04-01

    The safety integrity level (SIL) of equipment used in safety instrumented functions is determined by the average probability of failure on demand (PFDavg) computed at the time of periodic inspection and maintenance, i.e., the time of proof testing. The computation of PFDavg is generally based solely on predictions or estimates of the assumed constant failure rate of the equipment. However, PFDavg is also affected by maintenance actions (or lack thereof) taken by the end user. This paper shows how maintenance actions can affect the PFDavg of spring operated pressure relief valves (SOPRV) and how these maintenance actions may be accounted for in the computation of the PFDavg metric. The method provides a means for quantifying the effects of changes in maintenance practices and shows how these changes impact plant safety.

  5. The Effects of Maintenance Actions on the PFDavg of Spring Operated Pressure Relief Valves

    SciTech Connect

    Harris, S.; Gross, R.; Goble, W; Bukowski, J

    2015-12-01

    The safety integrity level (SIL) of equipment used in safety instrumented functions is determined by the average probability of failure on demand (PFDavg) computed at the time of periodic inspection and maintenance, i.e., the time of proof testing. The computation of PFDavg is generally based solely on predictions or estimates of the assumed constant failure rate of the equipment. However, PFDavg is also affected by maintenance actions (or lack thereof) taken by the end user. This paper shows how maintenance actions can affect the PFDavg of spring operated pressure relief valves (SOPRV) and how these maintenance actions may be accounted for in the computation of the PFDavg metric. The method provides a means for quantifying the effects of changes in maintenance practices and shows how these changes impact plant safety.

  6. The Effects of Maintenance Actions on the PFDavg of Spring Operated Pressure Relief Valves

    DOE PAGES

    Harris, S.; Gross, R.; Goble, W; ...

    2015-12-01

    The safety integrity level (SIL) of equipment used in safety instrumented functions is determined by the average probability of failure on demand (PFDavg) computed at the time of periodic inspection and maintenance, i.e., the time of proof testing. The computation of PFDavg is generally based solely on predictions or estimates of the assumed constant failure rate of the equipment. However, PFDavg is also affected by maintenance actions (or lack thereof) taken by the end user. This paper shows how maintenance actions can affect the PFDavg of spring operated pressure relief valves (SOPRV) and how these maintenance actions may be accountedmore » for in the computation of the PFDavg metric. The method provides a means for quantifying the effects of changes in maintenance practices and shows how these changes impact plant safety.« less

  7. 49 CFR 178.338-8 - Pressure relief devices, piping, valves, and fittings.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...) SPECIFICATIONS FOR PACKAGINGS Specifications for Containers for Motor Vehicle Transportation § 178.338-8 Pressure... pressure parts, except for pump seals and pressure relief devices, must be at least 4 times the...

  8. Analysis of operational methane emissions from pressure relief valves from biogas storages of biogas plants.

    PubMed

    Reinelt, Torsten; Liebetrau, Jan; Nelles, Michael

    2016-10-01

    The study presents the development of a method for the long term monitoring of methane emissions from pressure relief valves (PRV(1)) of biogas storages, which has been verified during test series at two PRVs of two agricultural biogas plants located in Germany. The determined methane emission factors are 0.12gCH4kWhel(-1) (0.06% CH4-loss, within 106days, 161 triggering events, winter season) from biogas plant A and 6.80/7.44gCH4kWhel(-1) (3.60/3.88% CH4-loss, within 66days, 452 triggering events, summer season) from biogas plant B. Besides the operational state of the biogas plant (e.g. malfunction of the combined heat and power unit), the mode of operation of the biogas flare, which can be manually or automatically operated as well as the atmospheric conditions (e.g. drop of the atmospheric pressure) can also affect the biogas emission from PRVs.

  9. VALIDATION OF SPRING OPERATED PRESSURE RELIEF VALVE TIME TO FAILURE AND THE IMPORTANCE OF STATISTICALLY SUPPORTED MAINTENANCE INTERVALS

    SciTech Connect

    Gross, R; Stephen Harris, S

    2009-02-18

    The Savannah River Site operates a Relief Valve Repair Shop certified by the National Board of Pressure Vessel Inspectors to NB-23, The National Board Inspection Code. Local maintenance forces perform inspection, testing, and repair of approximately 1200 spring-operated relief valves (SORV) each year as the valves are cycled in from the field. The Site now has over 7000 certified test records in the Computerized Maintenance Management System (CMMS); a summary of that data is presented in this paper. In previous papers, several statistical techniques were used to investigate failure on demand and failure rates including a quantal response method for predicting the failure probability as a function of time in service. The non-conservative failure mode for SORV is commonly termed 'stuck shut'; industry defined as the valve opening at greater than or equal to 1.5 times the cold set pressure. Actual time to failure is typically not known, only that failure occurred some time since the last proof test (censored data). This paper attempts to validate the assumptions underlying the statistical lifetime prediction results using Monte Carlo simulation. It employs an aging model for lift pressure as a function of set pressure, valve manufacturer, and a time-related aging effect. This paper attempts to answer two questions: (1) what is the predicted failure rate over the chosen maintenance/ inspection interval; and do we understand aging sufficient enough to estimate risk when basing proof test intervals on proof test results?

  10. 49 CFR 178.337-9 - Pressure relief devices, piping, valves, hoses, and fittings.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ..., valves, hose, and fittings. (1) The burst pressure of all piping, pipe fittings, hose and other pressure... of the cargo tank. Additionally, the burst pressure may not be less than 4 times any higher pressure... must be tested for leakage at not less than 225 psig using dry air or inert gas. (c) Marking inlets...

  11. 49 CFR 178.338-8 - Pressure relief devices, piping, valves, and fittings.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...) Piping, valves, and fittings. (1) The burst pressure of all piping, pipe fittings, hoses and other... pressure of the tank. Additionally, the burst pressure may not be less than 4 times any higher pressure to..., and fittings have been tested after installation with gas or air and proved leak tight at not...

  12. 49 CFR 178.338-8 - Pressure relief devices, piping, valves, and fittings.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...) Piping, valves, and fittings. (1) The burst pressure of all piping, pipe fittings, hoses and other... pressure of the tank. Additionally, the burst pressure may not be less than 4 times any higher pressure to..., and fittings have been tested after installation with gas or air and proved leak tight at not...

  13. 49 CFR 178.338-8 - Pressure relief devices, piping, valves, and fittings.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...) Piping, valves, and fittings. (1) The burst pressure of all piping, pipe fittings, hoses and other... pressure of the tank. Additionally, the burst pressure may not be less than 4 times any higher pressure to..., and fittings have been tested after installation with gas or air and proved leak tight at not...

  14. Refuge alternatives relief valve testing and design

    PubMed Central

    Lutz, T.J.; Bissert, P.T.; Homce, G.T.; Yonkey, J.A.

    2016-01-01

    The U.S. National Institute for Occupational Safety and Health (NIOSH) has been researching refuge alternatives (RAs) since 2007. RAs typically have built-in pressure relief valves (PRVs) to prevent the unit from reaching unsafe pressures. The U.S. Mine Safety and Health Administration requires that these valves vent the chamber at a maximum pressure of 1.25 kPa (0.18 psi, 5.0 in. H2O), or as specified by the manufacturer, above mine atmospheric pressure in the RA. To facilitate PRV testing, an instrumented benchtop test fixture was developed using an off-the-shelf centrifugal blower and ductwork. Relief pressures and flow characteristics were measured for three units: (1) a modified polyvinyl chloride check valve, (2) an off-the-shelf brass/cast-iron butterfly check valve and (3) a commercially available valve that was designed specifically for one manufacturer’s steel prefabricated RAs and had been adapted for use in one mine operator’s built-in-place RA. PRVs used in tent-style RAs were not investigated. The units were tested with different modifications and configurations in order to check compliance with Title 30 Code of Federal Regulations, or 30 CFR, regulations. The commercially available relief valve did not meet the 30 CFR relief pressure specification but may meet the manufacturer’s specification. Alternative valve designs were modified to meet the 30 CFR relief pressure specification, but all valve designs will need further design research to examine survivability in the event of a 103 kPa (15.0 psi) impulse overpressure during a disaster. PMID:28018003

  15. Refuge alternatives relief valve testing and design.

    PubMed

    Lutz, T J; Bissert, P T; Homce, G T; Yonkey, J A

    2016-10-01

    The U.S. National Institute for Occupational Safety and Health (NIOSH) has been researching refuge alternatives (RAs) since 2007. RAs typically have built-in pressure relief valves (PRVs) to prevent the unit from reaching unsafe pressures. The U.S. Mine Safety and Health Administration requires that these valves vent the chamber at a maximum pressure of 1.25 kPa (0.18 psi, 5.0 in. H2O), or as specified by the manufacturer, above mine atmospheric pressure in the RA. To facilitate PRV testing, an instrumented benchtop test fixture was developed using an off-the-shelf centrifugal blower and ductwork. Relief pressures and flow characteristics were measured for three units: (1) a modified polyvinyl chloride check valve, (2) an off-the-shelf brass/cast-iron butterfly check valve and (3) a commercially available valve that was designed specifically for one manufacturer's steel prefabricated RAs and had been adapted for use in one mine operator's built-in-place RA. PRVs used in tent-style RAs were not investigated. The units were tested with different modifications and configurations in order to check compliance with Title 30 Code of Federal Regulations, or 30 CFR, regulations. The commercially available relief valve did not meet the 30 CFR relief pressure specification but may meet the manufacturer's specification. Alternative valve designs were modified to meet the 30 CFR relief pressure specification, but all valve designs will need further design research to examine survivability in the event of a 103 kPa (15.0 psi) impulse overpressure during a disaster.

  16. 49 CFR 178.337-9 - Pressure relief devices, piping, valves, hoses, and fittings.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... chlorine service, see paragraph (b)(7) of this section. (2) Pipe joints must be threaded, welded, or... subchapter. (iii) Mark each hose assembly with the month and year of its original pressure test. (8) Chlorine cargo tanks. Angle valves on cargo tanks intended for chlorine service must conform to the standards...

  17. 49 CFR 178.337-9 - Pressure relief devices, piping, valves, hoses, and fittings.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... chlorine service, see paragraph (b)(7) of this section. (2) Pipe joints must be threaded, welded, or... subchapter. (iii) Mark each hose assembly with the month and year of its original pressure test. (8) Chlorine cargo tanks. Angle valves on cargo tanks intended for chlorine service must conform to the standards...

  18. 49 CFR 178.337-9 - Pressure relief devices, piping, valves, hoses, and fittings.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... in service. For chlorine service, see paragraph (b)(7) of this section. (2) Pipe joints must be... original pressure test. (8) Chlorine cargo tanks. Angle valves on cargo tanks intended for chlorine service must conform to the standards of the Chlorine Institute, Inc., Dwg. 104-8 or “Section 3, Pamphlet...

  19. 49 CFR 178.337-9 - Pressure relief devices, piping, valves, hoses, and fittings.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... chlorine service, see paragraph (b)(7) of this section. (2) Pipe joints must be threaded, welded, or... subchapter. (iii) Mark each hose assembly with the month and year of its original pressure test. (8) Chlorine cargo tanks. Angle valves on cargo tanks intended for chlorine service must conform to the standards...

  20. Research on the water hammer protection of the long distance water supply project with the combined action of the air vessel and over-pressure relief valve

    NASA Astrophysics Data System (ADS)

    Li, D. D.; Jiang, J.; Zhao, Z.; Yi, W. S.; Lan, G.

    2013-12-01

    We take a concrete pumping station as an example in this paper. Through the calculation of water hammer protection with a specific pumping station water supply project, and the analysis of the principle, mathematical models and boundary conditions of air vessel and over-pressure relief valve we show that the air vessel can protect the water conveyance system and reduce the transient pressure damage due to various causes. Over-pressure relief valve can effectively reduce the water hammer because the water column re-bridge suddenly stops the pump and prevents pipeline burst. The paper indicates that the combination set of air vessel and over-pressure relief valve can greatly reduce the quantity of the air valve and can eliminate the water hammer phenomenon in the pipeline system due to the vaporization and water column separation and re-bridge. The conclusion could provide a reference for the water hammer protection of long-distance water supply system.

  1. 46 CFR 54.15-10 - Safety and relief valves (modifies UG-126).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... relief valves shall be of the direct spring loaded type. (c) Safety and relief valves for steam or air... cast iron are prohibited. (g) The spring in a relief valve in service for pressures up to and including... percent below that for which the relief valve is marked. For higher pressures, the spring shall not...

  2. 46 CFR 54.15-10 - Safety and relief valves (modifies UG-126).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... relief valves shall be of the direct spring loaded type. (c) Safety and relief valves for steam or air... cast iron are prohibited. (g) The spring in a relief valve in service for pressures up to and including... percent below that for which the relief valve is marked. For higher pressures, the spring shall not...

  3. Navier-Stokes flow field analysis of compressible flow in a high pressure safety relief valve

    NASA Technical Reports Server (NTRS)

    Vu, Bruce; Wang, Ten-See; Shih, Ming-Hsin; Soni, Bharat

    1993-01-01

    The objective of this study is to investigate the complex three-dimensional flowfield of an oxygen safety pressure relieve valve during an incident, with a computational fluid dynamic (CFD) analysis. Specifically, the analysis will provide a flow pattern that would lead to the expansion of the eventual erosion pattern of the hardware, so as to combine it with other findings to piece together a most likely scenario for the investigation. The CFD model is a pressure based solver. An adaptive upwind difference scheme is employed for the spatial discretization, and a predictor, multiple corrector method is used for the velocity-pressure coupling. The computational result indicated vortices formation near the opening of the valve which matched the erosion pattern of the damaged hardware.

  4. 46 CFR 154.802 - Alternate pressure relief settings.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Alternate pressure relief settings. 154.802 Section 154... Equipment Cargo Vent Systems § 154.802 Alternate pressure relief settings. Cargo tanks with more than one relief valve setting must have one of the following arrangements: (a) Relief valves that: (1) Are set...

  5. Aging and service wear of spring-loaded pressure relief valves used in safety-related systems at nuclear power plants

    SciTech Connect

    Staunton, R.H.; Cox, D.F.

    1995-03-01

    Spring-loaded pressure relief valves (PRVS) are used in some safety-related applications at nuclear power plants. In general, they are used in systems where, during accidents, pressures may rise to levels where pressure safety relief is required for protection of personnel, system piping, and components. This report documents a study of PRV aging and considers the severity and causes of service wear and how it is discovered and corrected in various systems, valve sizes, etc. Provided in this report are results of the examination of the recorded failures and identification of trends and relationships/correlations in the failures when all failure-related parameters are considered. Components that comprise a typical PRV, how those components fail, when they fail, and the current testing frequencies and methods are also presented in detail.

  6. 46 CFR 54.15-10 - Safety and relief valves (modifies UG-126).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... of cast iron. Safety relief valves used in liquefied compressed gas service shall meet subpart 162... reference; see 46 CFR 54.01-1). (f) Cast iron may be employed in the construction of relief valves for... cast iron are prohibited. (g) The spring in a relief valve in service for pressures up to and...

  7. 46 CFR 54.15-10 - Safety and relief valves (modifies UG-126).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... of cast iron. Safety relief valves used in liquefied compressed gas service shall meet subpart 162... reference; see 46 CFR 54.01-1). (f) Cast iron may be employed in the construction of relief valves for... cast iron are prohibited. (g) The spring in a relief valve in service for pressures up to and...

  8. MERADCOM/OSU Assessment and Rating of the Contaminant Sensitivity of Relief Valves.

    DTIC Science & Technology

    1980-10-01

    valve . Contaminant wear on the poppet also causes a decrease in the reseating pressure of a relief valve . This...teristics of the valve . As the physical shape of the poppet or piston is changed due to wear , the flow forces acting upon them are also changed. This results...Contaminant Wear Erosive Wear Abrasive Wear Contaminant Lock Direct-Acting Relief Valves Pilot-Operated Relief Valves Contaminant Tolerance Profile

  9. 49 CFR 230.49 - Setting of safety relief valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Setting of safety relief valves. 230.49 Section... Appurtenances Safety Relief Valves § 230.49 Setting of safety relief valves. (a) Qualifications of individual who adjusts. Safety relief valves shall be set and adjusted by a competent person who is...

  10. 49 CFR 230.49 - Setting of safety relief valves.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 4 2014-10-01 2014-10-01 false Setting of safety relief valves. 230.49 Section... Appurtenances Safety Relief Valves § 230.49 Setting of safety relief valves. (a) Qualifications of individual who adjusts. Safety relief valves shall be set and adjusted by a competent person who is...

  11. 49 CFR 230.49 - Setting of safety relief valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Setting of safety relief valves. 230.49 Section... Appurtenances Safety Relief Valves § 230.49 Setting of safety relief valves. (a) Qualifications of individual who adjusts. Safety relief valves shall be set and adjusted by a competent person who is...

  12. 49 CFR 230.49 - Setting of safety relief valves.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 4 2013-10-01 2013-10-01 false Setting of safety relief valves. 230.49 Section... Appurtenances Safety Relief Valves § 230.49 Setting of safety relief valves. (a) Qualifications of individual who adjusts. Safety relief valves shall be set and adjusted by a competent person who is...

  13. 49 CFR 230.49 - Setting of safety relief valves.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 4 2012-10-01 2012-10-01 false Setting of safety relief valves. 230.49 Section... Appurtenances Safety Relief Valves § 230.49 Setting of safety relief valves. (a) Qualifications of individual who adjusts. Safety relief valves shall be set and adjusted by a competent person who is...

  14. 49 CFR 179.100-19 - Tests of safety relief valves.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.100-19 Tests of safety relief valves. (a) Each valve shall be tested by air or gas for compliance with §...

  15. 49 CFR 179.100-19 - Tests of safety relief valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.100-19 Tests of safety relief valves. (a) Each valve shall be tested by air or gas for compliance with §...

  16. 49 CFR 179.100-19 - Tests of safety relief valves.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.100-19 Tests of safety relief valves. (a) Each valve shall be tested by air or gas for compliance with §...

  17. 49 CFR 179.100-19 - Tests of safety relief valves.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... CARS Specifications for Pressure Tank Car Tanks (Classes DOT-105, 109, 112, 114 and 120) § 179.100-19 Tests of safety relief valves. (a) Each valve shall be tested by air or gas for compliance with §...

  18. 46 CFR 53.05-2 - Relief valve requirements for hot water boilers (modifies HG-400.2).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Relief valve requirements for hot water boilers... (CONTINUED) MARINE ENGINEERING HEATING BOILERS Pressure Relieving Devices (Article 4) § 53.05-2 Relief valve requirements for hot water boilers (modifies HG-400.2). (a) The relief valve requirements for hot water...

  19. 46 CFR 53.05-2 - Relief valve requirements for hot water boilers (modifies HG-400.2).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Relief valve requirements for hot water boilers... (CONTINUED) MARINE ENGINEERING HEATING BOILERS Pressure Relieving Devices (Article 4) § 53.05-2 Relief valve requirements for hot water boilers (modifies HG-400.2). (a) The relief valve requirements for hot water...

  20. 46 CFR 53.05-2 - Relief valve requirements for hot water boilers (modifies HG-400.2).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Relief valve requirements for hot water boilers... (CONTINUED) MARINE ENGINEERING HEATING BOILERS Pressure Relieving Devices (Article 4) § 53.05-2 Relief valve requirements for hot water boilers (modifies HG-400.2). (a) The relief valve requirements for hot water...

  1. 46 CFR 53.05-2 - Relief valve requirements for hot water boilers (modifies HG-400.2).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Relief valve requirements for hot water boilers... (CONTINUED) MARINE ENGINEERING HEATING BOILERS Pressure Relieving Devices (Article 4) § 53.05-2 Relief valve requirements for hot water boilers (modifies HG-400.2). (a) The relief valve requirements for hot water...

  2. 46 CFR 53.05-2 - Relief valve requirements for hot water boilers (modifies HG-400.2).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Relief valve requirements for hot water boilers... (CONTINUED) MARINE ENGINEERING HEATING BOILERS Pressure Relieving Devices (Article 4) § 53.05-2 Relief valve requirements for hot water boilers (modifies HG-400.2). (a) The relief valve requirements for hot water...

  3. 5. DIABLO DAM: DETAIL VIEW OF RELIEF VALVES AT ELEVATION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    5. DIABLO DAM: DETAIL VIEW OF RELIEF VALVES AT ELEVATION 1044. VALVE IN FOREGROUND IS A BUTTERFLY VALVE SIX FEET IN DIAMETER; VALVE TO THE REAR IS A JOHNSON-TYPE NEEDLE VALVE BOTH VALVES WERE MANUFACTURED BY THE PELTON WATER WHEEL COMPANY, 1989. - Skagit Power Development, Diablo Dam, On Skagit River, 6.9 miles upstream from Newhalem, Newhalem, Whatcom County, WA

  4. 46 CFR 153.370 - Minimum relief valve setting for ambient temperature cargo tanks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Minimum relief valve setting for ambient temperature... temperature cargo tanks. The relief valve setting for a containment system that carries a cargo at ambient temperature must at least equal the cargo's vapor pressure at 46 °C (approx. 115 °F)....

  5. 46 CFR 153.370 - Minimum relief valve setting for ambient temperature cargo tanks.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Minimum relief valve setting for ambient temperature... temperature cargo tanks. The relief valve setting for a containment system that carries a cargo at ambient temperature must at least equal the cargo's vapor pressure at 46 °C (approx. 115 °F)....

  6. 46 CFR 153.370 - Minimum relief valve setting for ambient temperature cargo tanks.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Minimum relief valve setting for ambient temperature... temperature cargo tanks. The relief valve setting for a containment system that carries a cargo at ambient temperature must at least equal the cargo's vapor pressure at 46 °C (approx. 115 °F)....

  7. 46 CFR 153.370 - Minimum relief valve setting for ambient temperature cargo tanks.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Minimum relief valve setting for ambient temperature... temperature cargo tanks. The relief valve setting for a containment system that carries a cargo at ambient temperature must at least equal the cargo's vapor pressure at 46 °C (approx. 115 °F)....

  8. 46 CFR 153.370 - Minimum relief valve setting for ambient temperature cargo tanks.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Minimum relief valve setting for ambient temperature... temperature cargo tanks. The relief valve setting for a containment system that carries a cargo at ambient temperature must at least equal the cargo's vapor pressure at 46 °C (approx. 115 °F)....

  9. 8-inch Reflange Inlet and Two 6-inch 600# Flange Outlets Relief Valve Description and Specifications

    NASA Technical Reports Server (NTRS)

    2005-01-01

    In the past, an Anderson Greenwood (AG) pilot operated relief valve was used to protect the E-1 rocket engine test facility. It was found that the AG valve is destroyed and discharges internal parts at a great velocity on opening. This is a major safety and cost issue. The solution is a relief valve to match present Anderson Greenwood pilot valve A 8z B dimensions. The valve is to use a precise buckling pin obeying Euler s Law to act as the pressure sensor and actuator. The valve must not self destruct on opening.

  10. 49 CFR 179.500-16 - Tests of pressure relief devices.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Tests of pressure relief devices. 179.500-16... 107A) § 179.500-16 Tests of pressure relief devices. (a) Pressure relief valves shall be tested by air or gas before being put into service. Valve shall open at pressure not exceeding the marked...

  11. 46 CFR 56.50-20 - Pressure relief piping.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Pressure relief piping. 56.50-20 Section 56.50-20... APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-20 Pressure relief piping. (a) General... pressure-relieving safety devices shall be designed to facilitate drainage. (c) Stop valves. Stop...

  12. 46 CFR 56.50-20 - Pressure relief piping.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Pressure relief piping. 56.50-20 Section 56.50-20... APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-20 Pressure relief piping. (a) General... pressure-relieving safety devices shall be designed to facilitate drainage. (c) Stop valves. Stop...

  13. 46 CFR 56.50-20 - Pressure relief piping.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Pressure relief piping. 56.50-20 Section 56.50-20... APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-20 Pressure relief piping. (a) General... pressure-relieving safety devices shall be designed to facilitate drainage. (c) Stop valves. Stop...

  14. 46 CFR 56.50-20 - Pressure relief piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Pressure relief piping. 56.50-20 Section 56.50-20... APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-20 Pressure relief piping. (a) General... pressure-relieving safety devices shall be designed to facilitate drainage. (c) Stop valves. Stop...

  15. 46 CFR 56.50-20 - Pressure relief piping.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Pressure relief piping. 56.50-20 Section 56.50-20... APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-20 Pressure relief piping. (a) General... pressure-relieving safety devices shall be designed to facilitate drainage. (c) Stop valves. Stop...

  16. 46 CFR 64.79 - Inspection of pressure and vacuum relief device.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Inspection of pressure and vacuum relief device. 64.79... pressure and vacuum relief device. (a) The inspection of the pressure and vacuum relief device required in... of the accuracy of the pressure setting. (b) If the pressure and vacuum relief valve passes...

  17. 46 CFR 64.79 - Inspection of pressure and vacuum relief device.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Inspection of pressure and vacuum relief device. 64.79... pressure and vacuum relief device. (a) The inspection of the pressure and vacuum relief device required in... of the accuracy of the pressure setting. (b) If the pressure and vacuum relief valve passes...

  18. 46 CFR 64.79 - Inspection of pressure and vacuum relief device.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Inspection of pressure and vacuum relief device. 64.79... pressure and vacuum relief device. (a) The inspection of the pressure and vacuum relief device required in... of the accuracy of the pressure setting. (b) If the pressure and vacuum relief valve passes...

  19. 46 CFR 64.79 - Inspection of pressure and vacuum relief device.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Inspection of pressure and vacuum relief device. 64.79... pressure and vacuum relief device. (a) The inspection of the pressure and vacuum relief device required in... of the accuracy of the pressure setting. (b) If the pressure and vacuum relief valve passes...

  20. 46 CFR 64.79 - Inspection of pressure and vacuum relief device.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Inspection of pressure and vacuum relief device. 64.79... pressure and vacuum relief device. (a) The inspection of the pressure and vacuum relief device required in... of the accuracy of the pressure setting. (b) If the pressure and vacuum relief valve passes...

  1. 49 CFR 179.500-16 - Tests of pressure relief devices.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 107A) § 179.500-16 Tests of pressure relief devices. (a) Pressure relief valves shall be tested by air... devices that incorporate a rupture disc, samples of the discs used shall burst at a pressure not...

  2. 49 CFR 179.500-16 - Tests of pressure relief devices.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 107A) § 179.500-16 Tests of pressure relief devices. (a) Pressure relief valves shall be tested by air... devices that incorporate a rupture disc, samples of the discs used shall burst at a pressure not...

  3. 49 CFR 179.500-16 - Tests of pressure relief devices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 107A) § 179.500-16 Tests of pressure relief devices. (a) Pressure relief valves shall be tested by air... devices that incorporate a rupture disc, samples of the discs used shall burst at a pressure not...

  4. 46 CFR 154.801 - Pressure relief systems.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Pressure relief systems. 154.801 Section 154.801... Vent Systems § 154.801 Pressure relief systems. (a) Each cargo tank that has a volume of 20m3 (706 ft.3) or less must have at least one pressure relief valve. (b) Each cargo tank that has a volume of...

  5. 46 CFR 154.801 - Pressure relief systems.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Pressure relief systems. 154.801 Section 154.801... Vent Systems § 154.801 Pressure relief systems. (a) Each cargo tank that has a volume of 20m3 (706 ft.3) or less must have at least one pressure relief valve. (b) Each cargo tank that has a volume of...

  6. 46 CFR 154.801 - Pressure relief systems.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Pressure relief systems. 154.801 Section 154.801... Vent Systems § 154.801 Pressure relief systems. (a) Each cargo tank that has a volume of 20m3 (706 ft.3) or less must have at least one pressure relief valve. (b) Each cargo tank that has a volume of...

  7. 46 CFR 154.801 - Pressure relief systems.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Pressure relief systems. 154.801 Section 154.801... Vent Systems § 154.801 Pressure relief systems. (a) Each cargo tank that has a volume of 20m3 (706 ft.3) or less must have at least one pressure relief valve. (b) Each cargo tank that has a volume of...

  8. 46 CFR 153.368 - Pressure-vacuum valves.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Pressure-vacuum valves. 153.368 Section 153.368 Shipping... Systems § 153.368 Pressure-vacuum valves. (a) The pressure side of a required pressure-vacuum relief valve must begin to open only at a pressure exceeding 3.5 kPa gauge (approx. 0.5 psig). (b) A...

  9. 46 CFR 153.368 - Pressure-vacuum valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Pressure-vacuum valves. 153.368 Section 153.368 Shipping... Systems § 153.368 Pressure-vacuum valves. (a) The pressure side of a required pressure-vacuum relief valve must begin to open only at a pressure exceeding 3.5 kPa gauge (approx. 0.5 psig). (b) A...

  10. 46 CFR 153.368 - Pressure-vacuum valves.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Pressure-vacuum valves. 153.368 Section 153.368 Shipping... Systems § 153.368 Pressure-vacuum valves. (a) The pressure side of a required pressure-vacuum relief valve must begin to open only at a pressure exceeding 3.5 kPa gauge (approx. 0.5 psig). (b) A...

  11. 46 CFR 153.368 - Pressure-vacuum valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Pressure-vacuum valves. 153.368 Section 153.368 Shipping... Systems § 153.368 Pressure-vacuum valves. (a) The pressure side of a required pressure-vacuum relief valve must begin to open only at a pressure exceeding 3.5 kPa gauge (approx. 0.5 psig). (b) A...

  12. 46 CFR 153.368 - Pressure-vacuum valves.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Pressure-vacuum valves. 153.368 Section 153.368 Shipping... Systems § 153.368 Pressure-vacuum valves. (a) The pressure side of a required pressure-vacuum relief valve must begin to open only at a pressure exceeding 3.5 kPa gauge (approx. 0.5 psig). (b) A...

  13. 46 CFR 38.10-15 - Safety relief valves-TB/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Safety relief valves-TB/ALL. 38.10-15 Section 38.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS LIQUEFIED FLAMMABLE GASES Piping, Valves... excessive external pressure. (f) Void spaces between the primary and secondary barriers of...

  14. 46 CFR 38.10-15 - Safety relief valves-TB/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Safety relief valves-TB/ALL. 38.10-15 Section 38.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS LIQUEFIED FLAMMABLE GASES Piping, Valves... excessive external pressure. (f) Void spaces between the primary and secondary barriers of...

  15. 49 CFR 179.300-17 - Tests of pressure relief devices.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Tests of pressure relief devices. 179.300-17... pressure relief devices. (a) Each valve shall be tested by air or gas before being put into service. The valve shall open and be vapor-tight at the pressure prescribed in § 179.301. (b) Rupture disks of...

  16. 100. INTERIOR OF SKID 9A: VENT VALVE AND RELIEF VALVE ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    100. INTERIOR OF SKID 9A: VENT VALVE AND RELIEF VALVE FOR RAPID-LOAD LIQUID OXYGEN TANK - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  17. 119. Relief and safety valve of turbine unit no. 1, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    119. Relief and safety valve of turbine unit no. 1, located in the subway below the Generator Room; looking south. The safety valve was manufactured by the Chapman Valve Company of Springfield, Massachusetts. It is identical to the adjacent safety valve for turbine unit no. 2. Photo by Jet Lowe, HAER, 1989. - Puget Sound Power & Light Company, White River Hydroelectric Project, 600 North River Avenue, Dieringer, Pierce County, WA

  18. 49 CFR 179.500-16 - Tests of pressure relief devices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... tested by air or gas before being put into service. Valve shall open at pressure not exceeding the marked... relief devices that incorporate a rupture disc, samples of the discs used shall burst at a pressure...

  19. An experimental study on the stability of a direct spring loaded poppet relief valve

    NASA Astrophysics Data System (ADS)

    Bazsó, C.; Hős, C. J.

    2013-10-01

    This paper presents detailed experimental results on the static and dynamic behaviour of a hydraulic pressure relief valve with poppet valve body, with a special emphasis on the parameters influencing the valve instability. The first part of the paper presents the static measurements; sonic velocity in the hydraulic hose, discharge coefficient and fluid flow forces. The results are compared to the data found in the literature and a reasonable agreement was found. The second part presents dynamic measurements of valve chatter. While varying the feed flow rate, pressure and displacement time histories were recorded for a wide range of set pressure. It is shown that the spectra of both signals have similar frequency content, moreover, the frequency of chatter is fairly constant for a wide parameter range, both in terms of flow rate and set pressure. The regimes of qualitatively different motion forms (stable operation, free, impacting and chaotic oscillations) are shown in the flow rate-set pressure parameter plane.

  20. 22. TURBINE PIT AREA GORGE POWERHOUSE SHOWING RELIEF VALVE FOR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    22. TURBINE PIT AREA GORGE POWERHOUSE SHOWING RELIEF VALVE FOR UNIT 23 IN FOREGROUND AND GOVERNOR OIL TANKS AND PUMPS IN THE LEFT REAR, 1989. - Skagit Power Development, Gorge Powerhouse, On Skagit River, 0.4 mile upstream from Newhalem, Newhalem, Whatcom County, WA

  1. 46 CFR 98.25-60 - Safety relief valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Safety relief valves. 98.25-60 Section 98.25-60 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in...

  2. 46 CFR 98.25-60 - Safety relief valves.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Safety relief valves. 98.25-60 Section 98.25-60 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in...

  3. 46 CFR 98.25-60 - Safety relief valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Safety relief valves. 98.25-60 Section 98.25-60 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in...

  4. 46 CFR 98.25-60 - Safety relief valves.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Safety relief valves. 98.25-60 Section 98.25-60 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in...

  5. 46 CFR 98.25-60 - Safety relief valves.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Safety relief valves. 98.25-60 Section 98.25-60 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CARGO AND MISCELLANEOUS VESSELS SPECIAL CONSTRUCTION, ARRANGEMENT, AND OTHER PROVISIONS FOR CERTAIN DANGEROUS CARGOES IN BULK Anhydrous Ammonia in...

  6. 46 CFR 154.519 - Piping relief valves.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS... cargo that is specially approved by the Commandant (CG-ENG). (b) A relief valve on a cargo pump that protects the cargo piping system must discharge into the pump suction....

  7. 46 CFR 154.519 - Piping relief valves.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS... cargo that is specially approved by the Commandant (CG-522). (b) A relief valve on a cargo pump that protects the cargo piping system must discharge into the pump suction....

  8. 46 CFR 154.519 - Piping relief valves.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS... cargo that is specially approved by the Commandant (CG-ENG). (b) A relief valve on a cargo pump that protects the cargo piping system must discharge into the pump suction....

  9. 46 CFR 154.519 - Piping relief valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) CERTAIN BULK DANGEROUS CARGOES SAFETY STANDARDS... cargo that is specially approved by the Commandant (CG-522). (b) A relief valve on a cargo pump that protects the cargo piping system must discharge into the pump suction....

  10. Recent performance experience with US light water reactor self-actuating safety and relief valves

    SciTech Connect

    Hammer, C.G.

    1996-12-01

    Over the past several years, there have been a number of operating reactor events involving performance of primary and secondary safety and relief valves in U.S. Light Water Reactors. There are several different types of safety and relief valves installed for overpressure protection of various safety systems throughout a typical nuclear power plant. The following discussion is limited to those valves in the reactor coolant systems (RCS) and main steam systems of pressurized water reactors (PWR) and in the RCS of boiling water reactors (BWR), all of which are self-actuating having a setpoint controlled by a spring-loaded disk acting against system fluid pressure. The following discussion relates some of the significant recent experience involving operating reactor events or various testing data. Some of the more unusual and interesting operating events or test data involving some of these designs are included, in addition to some involving a number of similar events and those which have generic applicability.

  11. 46 CFR 64.91 - Relief valve for the cargo pump discharge.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Relief valve for the cargo pump discharge. 64.91 Section... PORTABLE TANKS AND CARGO HANDLING SYSTEMS Cargo Handling System § 64.91 Relief valve for the cargo pump discharge. The cargo pump discharge must have a relief valve that is— (a) Fitted between the cargo...

  12. 46 CFR 64.91 - Relief valve for the cargo pump discharge.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Relief valve for the cargo pump discharge. 64.91 Section... PORTABLE TANKS AND CARGO HANDLING SYSTEMS Cargo Handling System § 64.91 Relief valve for the cargo pump discharge. The cargo pump discharge must have a relief valve that is— (a) Fitted between the cargo...

  13. 46 CFR 64.91 - Relief valve for the cargo pump discharge.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Relief valve for the cargo pump discharge. 64.91 Section... PORTABLE TANKS AND CARGO HANDLING SYSTEMS Cargo Handling System § 64.91 Relief valve for the cargo pump discharge. The cargo pump discharge must have a relief valve that is— (a) Fitted between the cargo...

  14. 46 CFR 64.91 - Relief valve for the cargo pump discharge.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Relief valve for the cargo pump discharge. 64.91 Section... PORTABLE TANKS AND CARGO HANDLING SYSTEMS Cargo Handling System § 64.91 Relief valve for the cargo pump discharge. The cargo pump discharge must have a relief valve that is— (a) Fitted between the cargo...

  15. 46 CFR 64.91 - Relief valve for the cargo pump discharge.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Relief valve for the cargo pump discharge. 64.91 Section... PORTABLE TANKS AND CARGO HANDLING SYSTEMS Cargo Handling System § 64.91 Relief valve for the cargo pump discharge. The cargo pump discharge must have a relief valve that is— (a) Fitted between the cargo...

  16. Evaluation by step response tests of prototype relief valves designed for YF-12 inlet stability bleed system

    NASA Technical Reports Server (NTRS)

    Dustin, M. O.; Neiner, G. H.

    1975-01-01

    Two stability bleed system relief valves were tested in a special dynamic test facility. These poppet valves are prototypes for a stability bleed system designed for use in a YF-12 flight inlet. One valve is unshielded, while the other has a special shield to eliminate the flow effect pressures on the piston. The tests determined the size of a damping orifice to be used during wind tunnel tests of the bleed system and verified an analog simulation of the valves. The effects of initial pressure level, pressure step size, and spring rate were investigated.

  17. 49 CFR 179.300-17 - Tests of pressure relief devices.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... CARS Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300-17 Tests of pressure relief devices. (a) Each valve shall be tested by air or gas before being put into service. The... Cars (IBR, see § 171.7 of this subchapter). (c) For pressure relief devices of the fusible plug type,...

  18. 49 CFR 179.300-17 - Tests of pressure relief devices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... FOR TANK CARS Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300-17 Tests of pressure relief devices. (a) Each valve shall be tested by air or gas before being put into... Specifications for Tank Cars (IBR, see § 171.7 of this subchapter). (c) For pressure relief devices of...

  19. 49 CFR 179.300-17 - Tests of pressure relief devices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... CARS Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300-17 Tests of pressure relief devices. (a) Each valve shall be tested by air or gas before being put into service. The... Cars (IBR, see § 171.7 of this subchapter). (c) For pressure relief devices of the fusible plug type,...

  20. 49 CFR 179.300-17 - Tests of pressure relief devices.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... CARS Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300-17 Tests of pressure relief devices. (a) Each valve shall be tested by air or gas before being put into service. The... Cars (IBR, see § 171.7 of this subchapter). (c) For pressure relief devices of the fusible plug type,...

  1. 46 CFR 38.25-10 - Safety relief valves-TB/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Safety relief valves-TB/ALL. 38.25-10 Section 38.25-10 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS LIQUEFIED FLAMMABLE GASES Periodic Tests and Inspections § 38.25-10 Safety relief valves—TB/ALL. (a) The cargo tank safety relief valves...

  2. LOX, GOX and Pressure Relief

    NASA Technical Reports Server (NTRS)

    McLeod, Ken; Stoltzfus, Joel

    2006-01-01

    Oxygen relief systems present a serious fire hazard risk with often severe consequences. This presentation offers a risk management solution strategy which encourages minimizing ignition hazards, maximizing best materials, and utilizing good practices. Additionally, the relief system should be designed for cleanability and ballistic flow. The use of the right metals, softgoods, and lubricants, along with the best assembly techniques, is stressed. Materials should also be tested if data is not available and a full hazard analysis should be conducted in an effort to minimize risk and harm.

  3. Conceptual design of pressure relief systems for cryogenic application

    SciTech Connect

    Grohmann, S.; Süßer, M.

    2014-01-29

    The conceptual design of pressure relief systems is an important aspect in the early phase of any cryogenic system design, because a prudent and responsible evaluation of relief systems involves much more than just relief devices. The conceptual design consists of various steps: At first, hazard scenarios must be considered and the worst-case scenario identified. Next, a staged interaction against pressure increase is to be defined. This is followed by the selection of the general type of pressure relief device for each stage, such as safety valve and rupture disc, respectively. Then, a decision concerning their locations, their capacities and specific features must be taken. Furthermore, it is mandatory to consider the inlet pressure drop and the back pressure in the exhaust line for sizing the safety devices. And last but not least, economic and environmental considerations must be made in case of releasing the medium to the atmosphere. The development of the system's safety concept calls for a risk management strategy based on identification and analysis of hazards, and consequent risk mitigation using a system-based approach in compliance with the standards.

  4. Conceptual design of pressure relief systems for cryogenic application

    NASA Astrophysics Data System (ADS)

    Grohmann, S.; Süßer, M.

    2014-01-01

    The conceptual design of pressure relief systems is an important aspect in the early phase of any cryogenic system design, because a prudent and responsible evaluation of relief systems involves much more than just relief devices. The conceptual design consists of various steps: At first, hazard scenarios must be considered and the worst-case scenario identified. Next, a staged interaction against pressure increase is to be defined. This is followed by the selection of the general type of pressure relief device for each stage, such as safety valve and rupture disc, respectively. Then, a decision concerning their locations, their capacities and specific features must be taken. Furthermore, it is mandatory to consider the inlet pressure drop and the back pressure in the exhaust line for sizing the safety devices. And last but not least, economic and environmental considerations must be made in case of releasing the medium to the atmosphere. The development of the system's safety concept calls for a risk management strategy based on identification and analysis of hazards, and consequent risk mitigation using a system-based approach in compliance with the standards.

  5. 49 CFR 179.400-20 - Pressure relief devices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Pressure relief devices. 179.400-20 Section 179...-20 Pressure relief devices. (a) The tank must be provided with pressure relief devices for the... safety appliances. Vent or weep holes in pressure relief devices are prohibited. All main pressure...

  6. 49 CFR 179.400-20 - Pressure relief devices.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Pressure relief devices. 179.400-20 Section 179...-20 Pressure relief devices. (a) The tank must be provided with pressure relief devices for the... safety appliances. Vent or weep holes in pressure relief devices are prohibited. All main pressure...

  7. 49 CFR 179.400-20 - Pressure relief devices.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Pressure relief devices. 179.400-20 Section 179...-20 Pressure relief devices. (a) The tank must be provided with pressure relief devices for the... safety appliances. Vent or weep holes in pressure relief devices are prohibited. All main pressure...

  8. 49 CFR 179.400-20 - Pressure relief devices.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Pressure relief devices. 179.400-20 Section 179...-20 Pressure relief devices. (a) The tank must be provided with pressure relief devices for the... safety appliances. Vent or weep holes in pressure relief devices are prohibited. All main pressure...

  9. FLUID PRESSURE AND CAM OPERATED VACUUM VALVE

    DOEpatents

    Batzer, T.H.

    1963-11-26

    An ultra-high vacuum valve that is bakable, reusable, and capable of being quickly opened and closed is described. A translationally movable valve gate having an annular ridge is adapted to contact an annular soft metal gasket disposed at the valve seat such that the soft metal gasket extends beyond the annular ridge on all sides. The valve gate is closed, by first laterally aligning the valve gate with the valve seat and then bringing the valve gate and valve seat into seating contact by the translational movement of a ramp-like wedging means that engages similar ramp-like stractures at the base of the valve gate to force the valve gate into essentially pressureless contact with the annular soft metal gasket. This gasket is then pressurized from beneath by a fluid thereby effecting a vacuura tight seal between the gasket and the ridge. (AEC)

  10. 49 CFR 179.400-20 - Pressure relief devices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Pressure relief devices. 179.400-20 Section 179... and 107A) § 179.400-20 Pressure relief devices. (a) The tank must be provided with pressure relief... structure, trucks and safety appliances. Vent or weep holes in pressure relief devices are prohibited....

  11. Pressure compensated flow control valve

    DOEpatents

    Minteer, Daniel J.

    1999-01-01

    The invention is an air flow control valve which is capable of maintaining a constant flow at the outlet despite changes in the inlet or outlet pressure. The device consists of a shell assembly with an inlet chamber and outlet chamber separated by a separation plate. The chambers are connected by an orifice. Also located within the inlet chamber is a port controller assembly. The port controller assembly consists of a differential pressure plate and port cap affixed thereon. The cap is able to slide in and out of the orifice separating the inlet and outlet chambers. When the pressure differential is sufficient, the differential pressure plate rises or falls to maintain a constant air flow. Movement of the port controller assembly does not require the use of seals, diaphragms, tight tolerances, bushings, bearings, hinges, guides, or lubricants.

  12. 46 CFR 36.10-1 - Cargo pump relief valves-TB/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Cargo pump relief valves-TB/ALL. 36.10-1 Section 36.10-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS ELEVATED TEMPERATURE CARGOES Piping, Valves, Fittings, and Accessory Equipment § 36.10-1 Cargo pump relief valves—TB/ALL. (a) Cargo...

  13. 46 CFR 36.10-1 - Cargo pump relief valves-TB/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Cargo pump relief valves-TB/ALL. 36.10-1 Section 36.10-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS ELEVATED TEMPERATURE CARGOES Piping, Valves, Fittings, and Accessory Equipment § 36.10-1 Cargo pump relief valves—TB/ALL. (a) Cargo...

  14. 46 CFR 36.10-1 - Cargo pump relief valves-TB/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Cargo pump relief valves-TB/ALL. 36.10-1 Section 36.10-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS ELEVATED TEMPERATURE CARGOES Piping, Valves, Fittings, and Accessory Equipment § 36.10-1 Cargo pump relief valves—TB/ALL. (a) Cargo...

  15. 46 CFR 36.10-1 - Cargo pump relief valves-TB/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Cargo pump relief valves-TB/ALL. 36.10-1 Section 36.10-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS ELEVATED TEMPERATURE CARGOES Piping, Valves, Fittings, and Accessory Equipment § 36.10-1 Cargo pump relief valves—TB/ALL. (a) Cargo...

  16. 46 CFR 56.50-25 - Safety and relief valve escape piping.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... supported and installed so that no stress is transmitted to the safety valve body. (c) Safety or relief... 46 Shipping 2 2010-10-01 2010-10-01 false Safety and relief valve escape piping. 56.50-25 Section... SYSTEMS AND APPURTENANCES Design Requirements Pertaining to Specific Systems § 56.50-25 Safety and...

  17. 46 CFR 153.371 - Minimum relief valve setting for refrigerated cargo tanks.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... steady state temperature obtained by a full tank of cargo with the refrigeration system operating under... Design and Equipment Cargo Venting Systems § 153.371 Minimum relief valve setting for refrigerated cargo tanks. The relief valve setting for a containment system that carries a refrigerated cargo must at...

  18. 46 CFR 38.10-15 - Safety relief valves-TB/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Safety relief valves-TB/ALL. 38.10-15 Section 38.10-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS LIQUEFIED FLAMMABLE GASES Piping, Valves, Fittings, and Accessory Equipment § 38.10-15 Safety relief valves—TB/ALL. (a) Each tank shall be...

  19. 46 CFR 36.10-1 - Cargo pump relief valves-TB/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Cargo pump relief valves-TB/ALL. 36.10-1 Section 36.10-1 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY TANK VESSELS ELEVATED TEMPERATURE CARGOES Piping, Valves, Fittings, and Accessory Equipment § 36.10-1 Cargo pump relief valves—TB/ALL. (a) Cargo...

  20. 49 CFR 179.500-12 - Pressure relief devices.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Pressure relief devices. 179.500-12 Section 179...-12 Pressure relief devices. (a) Tank shall be equipped with one or more pressure relief devices of... pressure equal to 70 percent of the marked test pressure of tank, flow capacity will be sufficient...

  1. 49 CFR 179.500-12 - Pressure relief devices.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Pressure relief devices. 179.500-12 Section 179...-12 Pressure relief devices. (a) Tank shall be equipped with one or more pressure relief devices of... pressure equal to 70 percent of the marked test pressure of tank, flow capacity will be sufficient...

  2. 49 CFR 179.500-12 - Pressure relief devices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Pressure relief devices. 179.500-12 Section 179...-12 Pressure relief devices. (a) Tank shall be equipped with one or more pressure relief devices of... pressure equal to 70 percent of the marked test pressure of tank, flow capacity will be sufficient...

  3. 49 CFR 179.500-12 - Pressure relief devices.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Pressure relief devices. 179.500-12 Section 179...-12 Pressure relief devices. (a) Tank shall be equipped with one or more pressure relief devices of... pressure equal to 70 percent of the marked test pressure of tank, flow capacity will be sufficient...

  4. Computational analysis of aircraft pressure relief doors

    NASA Astrophysics Data System (ADS)

    Schott, Tyler

    Modern trends in commercial aircraft design have sought to improve fuel efficiency while reducing emissions by operating at higher pressures and temperatures than ever before. Consequently, greater demands are placed on the auxiliary bleed air systems used for a multitude of aircraft operations. The increased role of bleed air systems poses significant challenges for the pressure relief system to ensure the safe and reliable operation of the aircraft. The core compartment pressure relief door (PRD) is an essential component of the pressure relief system which functions to relieve internal pressure in the core casing of a high-bypass turbofan engine during a burst duct over-pressurization event. The successful modeling and analysis of a burst duct event are imperative to the design and development of PRD's to ensure that they will meet the increased demands placed on the pressure relief system. Leveraging high-performance computing coupled with advances in computational analysis, this thesis focuses on a comprehensive computational fluid dynamics (CFD) study to characterize turbulent flow dynamics and quantify the performance of a core compartment PRD across a range of operating conditions and geometric configurations. The CFD analysis was based on a compressible, steady-state, three-dimensional, Reynolds-averaged Navier-Stokes approach. Simulations were analyzed, and results show that variations in freestream conditions, plenum environment, and geometric configurations have a non-linear impact on the discharge, moment, thrust, and surface temperature characteristics. The CFD study revealed that the underlying physics for this behavior is explained by the interaction of vortices, jets, and shockwaves. This thesis research is innovative and provides a comprehensive and detailed analysis of existing and novel PRD geometries over a range of realistic operating conditions representative of a burst duct over-pressurization event. Further, the study provides aircraft

  5. Development of large-capacity main steam isolation valves and safety relief valves for next-generation BWR plant

    SciTech Connect

    Mitsugu Nishimura; Shin-ichi Furukawa; Gen Itoh; Kikuo Takeshima

    2002-07-01

    A study was made of high capacity main steam isolation valves (MSIV) and safety relief valves (SRV) for the main steam line of a boiling water reactor (BWR). The next-generation BWR plants, which are planned to have higher thermal power, have raised concerns relating to the main steam line of an increase in maintenance work to SRVs and erosion of the MSIV valve seat due to the increased main steam flow velocity. In this research project, the capacity of the MSIV and SRV was increased and the valve configuration was changed in an attempt to solve these problems. (authors)

  6. 49 CFR 178.347-4 - Pressure relief.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Pressure relief. 178.347-4 Section 178.347-4... Containers for Motor Vehicle Transportation § 178.347-4 Pressure relief. (a) Each cargo tank must be equipped with a pressure and vacuum relief system in accordance with § 178.345-10 and this section. (b) Type...

  7. 49 CFR 178.346-3 - Pressure relief.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Pressure relief. 178.346-3 Section 178.346-3... Containers for Motor Vehicle Transportation § 178.346-3 Pressure relief. (a) Each cargo tank must be equipped with a pressure relief system in accordance with § 178.345-10 and this section. (b) Type...

  8. 49 CFR 178.346-3 - Pressure relief.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Pressure relief. 178.346-3 Section 178.346-3... Containers for Motor Vehicle Transportation § 178.346-3 Pressure relief. (a) Each cargo tank must be equipped with a pressure relief system in accordance with § 178.345-10 and this section. (b) Type...

  9. 49 CFR 179.15 - Pressure relief devices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Pressure relief devices. 179.15 Section 179.15... Design Requirements § 179.15 Pressure relief devices. Except for DOT Class 106, 107, 110, and 113 tank cars, tanks must have a pressure relief device, made of material compatible with the lading,...

  10. 49 CFR 179.15 - Pressure relief devices.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Pressure relief devices. 179.15 Section 179.15... § 179.15 Pressure relief devices. Except for DOT Class 106, 107, 110, and 113 tank cars, tanks must have a pressure relief device, made of material compatible with the lading, that conforms to...

  11. 49 CFR 178.346-3 - Pressure relief.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Pressure relief. 178.346-3 Section 178.346-3... Containers for Motor Vehicle Transportation § 178.346-3 Pressure relief. (a) Each cargo tank must be equipped with a pressure relief system in accordance with § 178.345-10 and this section. (b) Type...

  12. 49 CFR 178.346-3 - Pressure relief.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Pressure relief. 178.346-3 Section 178.346-3... Containers for Motor Vehicle Transportation § 178.346-3 Pressure relief. (a) Each cargo tank must be equipped with a pressure relief system in accordance with § 178.345-10 and this section. (b) Type...

  13. 49 CFR 179.15 - Pressure relief devices.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Pressure relief devices. 179.15 Section 179.15... § 179.15 Pressure relief devices. Except for DOT Class 106, 107, 110, and 113 tank cars, tanks must have a pressure relief device, made of material compatible with the lading, that conforms to...

  14. 49 CFR 178.347-4 - Pressure relief.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Pressure relief. 178.347-4 Section 178.347-4... Containers for Motor Vehicle Transportation § 178.347-4 Pressure relief. (a) Each cargo tank must be equipped with a pressure and vacuum relief system in accordance with § 178.345-10 and this section. (b) Type...

  15. 49 CFR 179.15 - Pressure relief devices.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Pressure relief devices. 179.15 Section 179.15... § 179.15 Pressure relief devices. Except for DOT Class 106, 107, 110, and 113 tank cars, tanks must have a pressure relief device, made of material compatible with the lading, that conforms to...

  16. 49 CFR 179.15 - Pressure relief devices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Pressure relief devices. 179.15 Section 179.15... § 179.15 Pressure relief devices. Except for DOT Class 106, 107, 110, and 113 tank cars, tanks must have a pressure relief device, made of material compatible with the lading, that conforms to...

  17. 49 CFR 178.347-4 - Pressure relief.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Pressure relief. 178.347-4 Section 178.347-4... Specifications for Containers for Motor Vehicle Transportation § 178.347-4 Pressure relief. (a) Each cargo tank must be equipped with a pressure and vacuum relief system in accordance with § 178.345-10 and...

  18. 49 CFR 178.347-4 - Pressure relief.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Pressure relief. 178.347-4 Section 178.347-4... Containers for Motor Vehicle Transportation § 178.347-4 Pressure relief. (a) Each cargo tank must be equipped with a pressure and vacuum relief system in accordance with § 178.345-10 and this section. (b) Type...

  19. 49 CFR 178.347-4 - Pressure relief.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Pressure relief. 178.347-4 Section 178.347-4... Containers for Motor Vehicle Transportation § 178.347-4 Pressure relief. (a) Each cargo tank must be equipped with a pressure and vacuum relief system in accordance with § 178.345-10 and this section. (b) Type...

  20. 49 CFR 178.346-3 - Pressure relief.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Pressure relief. 178.346-3 Section 178.346-3... Specifications for Containers for Motor Vehicle Transportation § 178.346-3 Pressure relief. (a) Each cargo tank must be equipped with a pressure relief system in accordance with § 178.345-10 and this section....

  1. 49 CFR 179.500-12 - Pressure relief devices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Pressure relief devices. 179.500-12 Section 179... and 107A) § 179.500-12 Pressure relief devices. (a) Tank shall be equipped with one or more pressure..., with tank filled with air at pressure equal to 70 percent of the marked test pressure of tank,...

  2. Combined pressure regulator and shutoff valve

    NASA Technical Reports Server (NTRS)

    Koch, E. F. (Inventor)

    1974-01-01

    A remotely operable pressure regulator and shutoff valve particularly suited for achieving high resolution and flow control, and positive shutoff is described. The valve is characterized by a spring-loaded ball coaxially aligned with a fluid port to be sealed, a spring-loaded pintle extended through the port into engagement with the ball, for controlling the position, a spring-loaded diaphragm for controlling the position of the pintle, and an axially displaceable spring supported by a movable stop which, in turn, is repositioned by a selectively operable stepper motor. Thus, the pressure-response characteristics for the valve can be varied through a selective repositioning of the stop.

  3. 46 CFR 64.57 - Acceptance of pressure relief devices.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Acceptance of pressure relief devices. 64.57 Section 64.57 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs §...

  4. 46 CFR 64.71 - Marking of pressure relief devices.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Marking of pressure relief devices. 64.71 Section 64.71 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.71...

  5. 46 CFR 64.71 - Marking of pressure relief devices.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Marking of pressure relief devices. 64.71 Section 64.71 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.71...

  6. 46 CFR 64.57 - Acceptance of pressure relief devices.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Acceptance of pressure relief devices. 64.57 Section 64.57 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs §...

  7. 46 CFR 64.57 - Acceptance of pressure relief devices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Acceptance of pressure relief devices. 64.57 Section 64.57 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs §...

  8. 46 CFR 64.57 - Acceptance of pressure relief devices.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Acceptance of pressure relief devices. 64.57 Section 64.57 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs §...

  9. 46 CFR 64.71 - Marking of pressure relief devices.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Marking of pressure relief devices. 64.71 Section 64.71 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.71...

  10. 46 CFR 64.71 - Marking of pressure relief devices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Marking of pressure relief devices. 64.71 Section 64.71 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.71...

  11. 46 CFR 64.57 - Acceptance of pressure relief devices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Acceptance of pressure relief devices. 64.57 Section 64.57 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs §...

  12. 46 CFR 64.71 - Marking of pressure relief devices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Marking of pressure relief devices. 64.71 Section 64.71 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.71...

  13. ANALYSIS OF SAFETY RELIEF VALVE PROOF TEST DATA TO OPTIMIZE LIFECYCLE MAINTENANCE COSTS

    SciTech Connect

    Gross, Robert; Harris, Stephen

    2007-08-01

    Proof test results were analyzed and compared with a proposed life cycle curve or hazard function and the limit of useful life. Relief valve proof testing procedures, statistical modeling, data collection processes, and time-in-service trends are presented. The resulting analysis of test data allows for the estimation of the PFD. Extended maintenance intervals to the limit of useful life as well as methodologies and practices for improving relief valve performance and reliability are discussed. A generic cost-benefit analysis and an expected life cycle cost reduction concludes that $90 million maintenance dollars might be avoided for a population of 3000 valves over 20 years.

  14. 46 CFR 154.802 - Alternate pressure relief settings.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false Alternate pressure relief settings. 154.802 Section 154... Equipment Cargo Vent Systems § 154.802 Alternate pressure relief settings. Cargo tanks with more than one...) Change the set pressure without pressure testing to verify the new setting; and (2) Can be...

  15. 46 CFR 154.802 - Alternate pressure relief settings.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Alternate pressure relief settings. 154.802 Section 154... Equipment Cargo Vent Systems § 154.802 Alternate pressure relief settings. Cargo tanks with more than one...) Change the set pressure without pressure testing to verify the new setting; and (2) Can be...

  16. 46 CFR 154.802 - Alternate pressure relief settings.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Alternate pressure relief settings. 154.802 Section 154... Equipment Cargo Vent Systems § 154.802 Alternate pressure relief settings. Cargo tanks with more than one...) Change the set pressure without pressure testing to verify the new setting; and (2) Can be...

  17. 46 CFR 154.802 - Alternate pressure relief settings.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Alternate pressure relief settings. 154.802 Section 154... Equipment Cargo Vent Systems § 154.802 Alternate pressure relief settings. Cargo tanks with more than one...) Change the set pressure without pressure testing to verify the new setting; and (2) Can be...

  18. 46 CFR 76.15-40 - Pressure relief.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 3 2010-10-01 2010-10-01 false Pressure relief. 76.15-40 Section 76.15-40 Shipping... Carbon Dioxide Extinguishing Systems, Details § 76.15-40 Pressure relief. (a) Where necessary, relatively... means for relieving excessive pressure accumulating within the compartment when the carbon dioxide...

  19. 46 CFR 95.16-35 - Pressure relief.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Pressure relief. 95.16-35 Section 95.16-35 Shipping... EQUIPMENT Fixed Clean Agent Gas Extinguishing Systems, Details § 95.16-35 Pressure relief. Tight... excessive pressure within the compartment when the extinguishing agent is injected....

  20. 46 CFR 95.16-35 - Pressure relief.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Pressure relief. 95.16-35 Section 95.16-35 Shipping... EQUIPMENT Fixed Clean Agent Gas Extinguishing Systems, Details § 95.16-35 Pressure relief. Tight... excessive pressure within the compartment when the extinguishing agent is injected....

  1. 46 CFR 154.517 - Piping: Liquid pressure relief.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false Piping: Liquid pressure relief. 154.517 Section 154.517... and Process Piping Systems § 154.517 Piping: Liquid pressure relief. The cargo loading and discharge crossover headers, cargo hoses, and cargo loading arms must have means to relieve cargo pressure and...

  2. 49 CFR 179.300-15 - Pressure relief devices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Pressure relief devices. 179.300-15 Section 179... Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300-15 Pressure relief devices... shall be sufficient to prevent building up pressure in tank in excess of 82.5 percent of the tank...

  3. 46 CFR 76.15-40 - Pressure relief.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 3 2011-10-01 2011-10-01 false Pressure relief. 76.15-40 Section 76.15-40 Shipping... Carbon Dioxide Extinguishing Systems, Details § 76.15-40 Pressure relief. (a) Where necessary, relatively... means for relieving excessive pressure accumulating within the compartment when the carbon dioxide...

  4. 46 CFR 154.517 - Piping: Liquid pressure relief.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false Piping: Liquid pressure relief. 154.517 Section 154.517... and Process Piping Systems § 154.517 Piping: Liquid pressure relief. The cargo loading and discharge crossover headers, cargo hoses, and cargo loading arms must have means to relieve cargo pressure and...

  5. 49 CFR 179.300-15 - Pressure relief devices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Pressure relief devices. 179.300-15 Section 179... Pressure relief devices. (a) Unless prohibited in part 173 of this subchapter, tanks shall be equipped with... total discharge capacity shall be sufficient to prevent building up pressure in tank in excess of...

  6. 49 CFR 178.345-10 - Pressure relief.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Pressure relief. 178.345-10 Section 178.345-10... Containers for Motor Vehicle Transportation § 178.345-10 Pressure relief. (a) Each cargo tank must be equipped to relieve pressure and vacuum conditions in conformance with this section and the...

  7. 46 CFR 193.15-40 - Pressure relief.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Pressure relief. 193.15-40 Section 193.15-40 Shipping... EQUIPMENT Carbon Dioxide Extinguishing Systems, Details § 193.15-40 Pressure relief. (a) Where necessary... suitable means for relieving excessive pressure accumulating within the compartment when the carbon...

  8. 46 CFR 193.15-40 - Pressure relief.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Pressure relief. 193.15-40 Section 193.15-40 Shipping... EQUIPMENT Carbon Dioxide and Clean Agent Extinguishing Systems, Details § 193.15-40 Pressure relief. (a... be provided with suitable means for relieving excessive pressure accumulating within the...

  9. 46 CFR 76.15-40 - Pressure relief.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 3 2014-10-01 2014-10-01 false Pressure relief. 76.15-40 Section 76.15-40 Shipping... Carbon Dioxide Extinguishing Systems, Details § 76.15-40 Pressure relief. (a) Where necessary, relatively... means for relieving excessive pressure accumulating within the compartment when the carbon dioxide...

  10. 46 CFR 154.517 - Piping: Liquid pressure relief.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false Piping: Liquid pressure relief. 154.517 Section 154.517... and Process Piping Systems § 154.517 Piping: Liquid pressure relief. The cargo loading and discharge crossover headers, cargo hoses, and cargo loading arms must have means to relieve cargo pressure and...

  11. 46 CFR 95.15-40 - Pressure relief.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Pressure relief. 95.15-40 Section 95.15-40 Shipping... EQUIPMENT Carbon Dioxide Extinguishing Systems, Details § 95.15-40 Pressure relief. (a) Where necessary... suitable means for relieving excessive pressure accumulating within the compartment when the carbon...

  12. 49 CFR 179.300-15 - Pressure relief devices.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Pressure relief devices. 179.300-15 Section 179... Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300-15 Pressure relief devices... shall be sufficient to prevent building up pressure in tank in excess of 82.5 percent of the tank...

  13. 46 CFR 193.15-40 - Pressure relief.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Pressure relief. 193.15-40 Section 193.15-40 Shipping... EQUIPMENT Carbon Dioxide and Clean Agent Extinguishing Systems, Details § 193.15-40 Pressure relief. (a... be provided with suitable means for relieving excessive pressure accumulating within the...

  14. 46 CFR 76.15-40 - Pressure relief.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 3 2013-10-01 2013-10-01 false Pressure relief. 76.15-40 Section 76.15-40 Shipping... Carbon Dioxide Extinguishing Systems, Details § 76.15-40 Pressure relief. (a) Where necessary, relatively... means for relieving excessive pressure accumulating within the compartment when the carbon dioxide...

  15. 46 CFR 193.15-40 - Pressure relief.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Pressure relief. 193.15-40 Section 193.15-40 Shipping... EQUIPMENT Carbon Dioxide and Clean Agent Extinguishing Systems, Details § 193.15-40 Pressure relief. (a... be provided with suitable means for relieving excessive pressure accumulating within the...

  16. 49 CFR 178.345-10 - Pressure relief.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Pressure relief. 178.345-10 Section 178.345-10... Containers for Motor Vehicle Transportation § 178.345-10 Pressure relief. (a) Each cargo tank must be equipped to relieve pressure and vacuum conditions in conformance with this section and the...

  17. 49 CFR 178.345-10 - Pressure relief.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Pressure relief. 178.345-10 Section 178.345-10... Containers for Motor Vehicle Transportation § 178.345-10 Pressure relief. (a) Each cargo tank must be equipped to relieve pressure and vacuum conditions in conformance with this section and the...

  18. 46 CFR 95.15-40 - Pressure relief.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Pressure relief. 95.15-40 Section 95.15-40 Shipping... EQUIPMENT Carbon Dioxide Extinguishing Systems, Details § 95.15-40 Pressure relief. (a) Where necessary... suitable means for relieving excessive pressure accumulating within the compartment when the carbon...

  19. 46 CFR 95.16-35 - Pressure relief.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Pressure relief. 95.16-35 Section 95.16-35 Shipping... EQUIPMENT Fixed Clean Agent Gas Extinguishing Systems, Details § 95.16-35 Pressure relief. Tight... excessive pressure within the compartment when the extinguishing agent is injected....

  20. 46 CFR 95.15-40 - Pressure relief.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Pressure relief. 95.15-40 Section 95.15-40 Shipping... EQUIPMENT Carbon Dioxide Extinguishing Systems, Details § 95.15-40 Pressure relief. (a) Where necessary... suitable means for relieving excessive pressure accumulating within the compartment when the carbon...

  1. 46 CFR 95.15-40 - Pressure relief.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Pressure relief. 95.15-40 Section 95.15-40 Shipping... EQUIPMENT Carbon Dioxide Extinguishing Systems, Details § 95.15-40 Pressure relief. (a) Where necessary... suitable means for relieving excessive pressure accumulating within the compartment when the carbon...

  2. 49 CFR 179.300-15 - Pressure relief devices.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Pressure relief devices. 179.300-15 Section 179... Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300-15 Pressure relief devices... shall be sufficient to prevent building up pressure in tank in excess of 82.5 percent of the tank...

  3. 49 CFR 178.345-10 - Pressure relief.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Pressure relief. 178.345-10 Section 178.345-10... Containers for Motor Vehicle Transportation § 178.345-10 Pressure relief. (a) Each cargo tank must be equipped to relieve pressure and vacuum conditions in conformance with this section and the...

  4. 46 CFR 193.15-40 - Pressure relief.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Pressure relief. 193.15-40 Section 193.15-40 Shipping... EQUIPMENT Carbon Dioxide Extinguishing Systems, Details § 193.15-40 Pressure relief. (a) Where necessary... suitable means for relieving excessive pressure accumulating within the compartment when the carbon...

  5. 46 CFR 95.15-40 - Pressure relief.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Pressure relief. 95.15-40 Section 95.15-40 Shipping... EQUIPMENT Carbon Dioxide Extinguishing Systems, Details § 95.15-40 Pressure relief. (a) Where necessary... suitable means for relieving excessive pressure accumulating within the compartment when the carbon...

  6. 49 CFR 179.300-15 - Pressure relief devices.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Pressure relief devices. 179.300-15 Section 179... Specifications for Multi-Unit Tank Car Tanks (Classes DOT-106A and 110AW) § 179.300-15 Pressure relief devices... shall be sufficient to prevent building up pressure in tank in excess of 82.5 percent of the tank...

  7. 49 CFR 178.345-10 - Pressure relief.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Pressure relief. 178.345-10 Section 178.345-10... Specifications for Containers for Motor Vehicle Transportation § 178.345-10 Pressure relief. (a) Each cargo tank must be equipped to relieve pressure and vacuum conditions in conformance with this section and...

  8. 46 CFR 76.15-40 - Pressure relief.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 3 2012-10-01 2012-10-01 false Pressure relief. 76.15-40 Section 76.15-40 Shipping... Carbon Dioxide Extinguishing Systems, Details § 76.15-40 Pressure relief. (a) Where necessary, relatively... means for relieving excessive pressure accumulating within the compartment when the carbon dioxide...

  9. 14 CFR 125.165 - Extinguishing agent container pressure relief.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... TRANSPORTATION (CONTINUED) AIR CARRIERS AND OPERATORS FOR COMPENSATION OR HIRE: CERTIFICATION AND OPERATIONS... provided with a pressure relief to prevent bursting of the container because of excessive...

  10. 14 CFR 125.165 - Extinguishing agent container pressure relief.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... TRANSPORTATION (CONTINUED) AIR CARRIERS AND OPERATORS FOR COMPENSATION OR HIRE: CERTIFICATION AND OPERATIONS... provided with a pressure relief to prevent bursting of the container because of excessive...

  11. 14 CFR 121.267 - Extinguishing agent container pressure relief.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... TRANSPORTATION (CONTINUED) AIR CARRIERS AND OPERATORS FOR COMPENSATION OR HIRE: CERTIFICATION AND OPERATIONS... with a pressure relief to prevent bursting of the container because of excessive internal...

  12. 14 CFR 125.165 - Extinguishing agent container pressure relief.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... TRANSPORTATION (CONTINUED) AIR CARRIERS AND OPERATORS FOR COMPENSATION OR HIRE: CERTIFICATION AND OPERATIONS... provided with a pressure relief to prevent bursting of the container because of excessive...

  13. 14 CFR 121.267 - Extinguishing agent container pressure relief.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... TRANSPORTATION (CONTINUED) AIR CARRIERS AND OPERATORS FOR COMPENSATION OR HIRE: CERTIFICATION AND OPERATIONS... with a pressure relief to prevent bursting of the container because of excessive internal...

  14. 14 CFR 121.267 - Extinguishing agent container pressure relief.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... TRANSPORTATION (CONTINUED) AIR CARRIERS AND OPERATORS FOR COMPENSATION OR HIRE: CERTIFICATION AND OPERATIONS... with a pressure relief to prevent bursting of the container because of excessive internal...

  15. 14 CFR 121.267 - Extinguishing agent container pressure relief.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... TRANSPORTATION (CONTINUED) AIR CARRIERS AND OPERATORS FOR COMPENSATION OR HIRE: CERTIFICATION AND OPERATIONS... with a pressure relief to prevent bursting of the container because of excessive internal...

  16. 14 CFR 125.165 - Extinguishing agent container pressure relief.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... TRANSPORTATION (CONTINUED) AIR CARRIERS AND OPERATORS FOR COMPENSATION OR HIRE: CERTIFICATION AND OPERATIONS... provided with a pressure relief to prevent bursting of the container because of excessive...

  17. 14 CFR 121.267 - Extinguishing agent container pressure relief.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... TRANSPORTATION (CONTINUED) AIR CARRIERS AND OPERATORS FOR COMPENSATION OR HIRE: CERTIFICATION AND OPERATIONS... with a pressure relief to prevent bursting of the container because of excessive internal...

  18. 14 CFR 125.165 - Extinguishing agent container pressure relief.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... TRANSPORTATION (CONTINUED) AIR CARRIERS AND OPERATORS FOR COMPENSATION OR HIRE: CERTIFICATION AND OPERATIONS... provided with a pressure relief to prevent bursting of the container because of excessive...

  19. 46 CFR 154.517 - Piping: Liquid pressure relief.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false Piping: Liquid pressure relief. 154.517 Section 154.517... and Process Piping Systems § 154.517 Piping: Liquid pressure relief. The cargo loading and discharge... remove liquid cargo....

  20. Examples, clarifications, and guidance on preparing requests for relief from pump and valve inservice testing requirements

    SciTech Connect

    Ransom, C.B.; Hartley, R.S.

    1996-02-01

    In this report, the Idaho National Engineering Laboratory reviewers discuss related to requests for relief from the American Society of Mechanical Engineers code requirements for inservice testing (IST) of safety-related pumps and valves at commercial nuclear power plants. This report compiles information and examples that may be useful to licensees in developing relief requests submitted to US Nuclear Regulatory Commission (NRC) for their consideration and provides insights and recommendations on related IST issues. The report also gives specific guidance on relief requests acceptable and not acceptable to the NRC and advises licensees in the use of this information for application at their facilities.

  1. 46 CFR 58.16-15 - Valves and safety relief devices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Valves and safety relief devices. 58.16-15 Section 58.16-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND AUXILIARY MACHINERY AND RELATED SYSTEMS Liquefied Petroleum Gases for Cooking and Heating § 58.16-15...

  2. 46 CFR 58.16-15 - Valves and safety relief devices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Valves and safety relief devices. 58.16-15 Section 58.16-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND AUXILIARY MACHINERY AND RELATED SYSTEMS Liquefied Petroleum Gases for Cooking and Heating § 58.16-15...

  3. 46 CFR 58.16-15 - Valves and safety relief devices.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Valves and safety relief devices. 58.16-15 Section 58.16-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND AUXILIARY MACHINERY AND RELATED SYSTEMS Liquefied Petroleum Gases for Cooking and Heating § 58.16-15...

  4. 46 CFR 58.16-15 - Valves and safety relief devices.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Valves and safety relief devices. 58.16-15 Section 58.16-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND AUXILIARY MACHINERY AND RELATED SYSTEMS Liquefied Petroleum Gases for Cooking and Heating § 58.16-15...

  5. 46 CFR 58.16-15 - Valves and safety relief devices.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Valves and safety relief devices. 58.16-15 Section 58.16-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MAIN AND AUXILIARY MACHINERY AND RELATED SYSTEMS Liquefied Petroleum Gases for Cooking and Heating § 58.16-15...

  6. 33 CFR 149.105 - What are the requirements for the overflow and relief valves?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false What are the requirements for the overflow and relief valves? 149.105 Section 149.105 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) DEEPWATER PORTS DEEPWATER PORTS: DESIGN, CONSTRUCTION, AND...

  7. 49 CFR 179.100-19 - Tests of safety relief valves.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 2 2010-10-01 2010-10-01 false Tests of safety relief valves. 179.100-19 Section 179.100-19 Transportation Other Regulations Relating to Transportation PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION HAZARDOUS MATERIALS REGULATIONS...

  8. Fluidised-bed combustion. IEA Grimethorpe Pressurized Fluidised-Bed Test Facility back-end valves: history and modification

    SciTech Connect

    Not Available

    1982-01-01

    The pressure of the combustor freeboard is controlled by one of three back-end pressure control valves. The back-end valves are so called as they are situated at the back end of the exhaust gas system at the outlet of the main exhaust gas heat exchanger. In normal operation one of the valves is on pressure control duty, another on pressure relief duty, and the third is shut and available for operation on control or relief duty. These valves are subjected to a very arduous duty: temperatures of up to 350/sup 0/C to 375/sup 0/C with pressure drops of approximately 8 bar, and an estimated solids content of up to 400 ppM in the exhaust gases. Severe erosion on the valves seats, shafts, seals and upstream and downstream pipework has occurred and a large amount of remedial work has been carried out on the valves and adjacent pipework. This report describes the history of the valve erosion, the maintenance/remedial work carried out, and the steps being taken to attempt to solve the problem for future tests.

  9. Study of pressing machine pressure relief characteristics based on AMESim

    NASA Astrophysics Data System (ADS)

    Wang, Chuanli; Zhang, Hui; Yu, Caofeng; Wu, Xiaolei

    2016-01-01

    When a working cylinder of the pressing machine working cylinder was stuck and underwent retracted conversion, pressure shock was high in working cylinder cavity and flow pulsation was distinct in the pipeline due to the high working pressure and frequent retracted transformation of the working cylinder, which not only shortened the service life of the pressing machine, but also exerted serious impacts on the machining precision and quality, especially after the pressing machine applied loads and high-pressure oil in work rod end cavity of working cylinder needed to be relieved in a short time. In order to research and analyze the better pressure relief characteristics of the two types of pressure relief circuits of the pressing machine, the paper established models, carried out simulation and analysis and then made contrastive analysis of the working cylinder rod velocity, rod acceleration and port pressure pulsation according to the simulation results.

  10. Self-aligning, low-pressure sealing poppet valve

    NASA Technical Reports Server (NTRS)

    Gonzalez, R.; Bratfisch, W. A.

    1972-01-01

    Design and characteristics of poppet valve operated by very low differential pressures to control fluid flow are described. Valve is used to control flow of petroleum, chemical, and aircraft hydraulics where low leakage rates and activation at low pressures are required.

  11. Hydraulic High Pressure Valve Controller Using the In-Situ Pressure Difference

    NASA Technical Reports Server (NTRS)

    Bao, Xiaoqi (Inventor); Sherrit, Stewart (Inventor); Badescu, Mircea (Inventor); Bar-Cohen, Yoseph (Inventor); Hall, Jeffery L. (Inventor)

    2016-01-01

    A hydraulic valve controller that uses an existing pressure differential as some or all of the power source for valve operation. In a high pressure environment, such as downhole in an oil or gas well, the pressure differential between the inside of a pipe and the outside of the pipe may be adequately large to drive a linear slide valve. The valve is operated hydraulically by a piston in a bore. When a higher pressure is applied to one end of the bore and a lower pressure to the other end, the piston moves in response to the pressure differential and drives a valve attached to it. If the pressure differential is too small to drive the piston at a sufficiently high speed, a pump is provided to generate a larger pressure differential to be applied. The apparatus is conveniently constructed using multiport valves, which can be rotary valves.

  12. 40 CFR 60.482-4 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., 2006 § 60.482-4 Standards: Pressure relief devices in gas/vapor service. (a) Except during pressure releases, each pressure relief device in gas/vapor service shall be operated with no detectable emissions... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standards: Pressure relief devices...

  13. 40 CFR 60.482-4 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., 2006 § 60.482-4 Standards: Pressure relief devices in gas/vapor service. (a) Except during pressure releases, each pressure relief device in gas/vapor service shall be operated with no detectable emissions... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standards: Pressure relief devices...

  14. 40 CFR 265.1054 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...: Pressure relief devices in gas/vapor service. (a) Except during pressure releases, each pressure relief... 40 Protection of Environment 27 2012-07-01 2012-07-01 false Standards: Pressure relief devices in gas/vapor service. 265.1054 Section 265.1054 Protection of Environment ENVIRONMENTAL PROTECTION...

  15. 40 CFR 60.482-4 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., 2006 § 60.482-4 Standards: Pressure relief devices in gas/vapor service. (a) Except during pressure releases, each pressure relief device in gas/vapor service shall be operated with no detectable emissions... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Standards: Pressure relief devices...

  16. 40 CFR 60.482-4 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., 2006 § 60.482-4 Standards: Pressure relief devices in gas/vapor service. (a) Except during pressure releases, each pressure relief device in gas/vapor service shall be operated with no detectable emissions... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Standards: Pressure relief devices...

  17. 40 CFR 265.1054 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...: Pressure relief devices in gas/vapor service. (a) Except during pressure releases, each pressure relief... 40 Protection of Environment 26 2014-07-01 2014-07-01 false Standards: Pressure relief devices in gas/vapor service. 265.1054 Section 265.1054 Protection of Environment ENVIRONMENTAL PROTECTION...

  18. 40 CFR 60.482-4 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., 2006 § 60.482-4 Standards: Pressure relief devices in gas/vapor service. (a) Except during pressure releases, each pressure relief device in gas/vapor service shall be operated with no detectable emissions... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standards: Pressure relief devices...

  19. 40 CFR 265.1054 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...: Pressure relief devices in gas/vapor service. (a) Except during pressure releases, each pressure relief... 40 Protection of Environment 27 2013-07-01 2013-07-01 false Standards: Pressure relief devices in gas/vapor service. 265.1054 Section 265.1054 Protection of Environment ENVIRONMENTAL PROTECTION...

  20. 40 CFR 265.1054 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...: Pressure relief devices in gas/vapor service. (a) Except during pressure releases, each pressure relief... 40 Protection of Environment 26 2011-07-01 2011-07-01 false Standards: Pressure relief devices in gas/vapor service. 265.1054 Section 265.1054 Protection of Environment ENVIRONMENTAL PROTECTION...

  1. 40 CFR 265.1054 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...: Pressure relief devices in gas/vapor service. (a) Except during pressure releases, each pressure relief... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Standards: Pressure relief devices in gas/vapor service. 265.1054 Section 265.1054 Protection of Environment ENVIRONMENTAL PROTECTION...

  2. Effects of a continuous lateral turning device on pressure relief

    PubMed Central

    Do, Nam Ho; Kim, Deog Young; Kim, Jung-Hoon; Choi, Jong Hyun; Joo, So Young; Kang, Na Kyung; Baek, Yoon Su

    2016-01-01

    [Purpose] The purpose of this study was to examine the pressure-relieving effects of a continuous lateral turning device on common pressure ulcer sites. [Subjects] Twenty-four healthy adults participated. [Methods] The design of our continuous lateral turning device was motivated by the need for an adequate pressure-relieving device for immobile and/or elderly people. The procedure of manual repositioning is embodied in our continuous lateral turning device. The interface pressure and time were measured, and comfort grade was evaluated during sessions of continuous lateral turning at 0°, 15°, 30°, and 45°. We quantified the pressure-relieving effect using peak pressure, mean pressure, and pressure time integration. [Results] Participants demonstrated pressure time integration values below the pressure-time threshold at 15°, 30°, and 45° at all the common pressure ulcer sites. Moreover, the most effective angles for pressure relief at the common pressure ulcer sites were 30° at the occiput, 15° at the left scapula, 45° at the right scapula, 45° at the sacrum, 15° at the right heel, and 30° at the left heel. However, angles greater than 30° induced discomfort. [Conclusion] Continuous lateral turning with our specially designed device effectively relieved the pressure of targeted sites. Moreover, the suggested angles of continuous lateral turning can be used to relieve pressure at targeted sites. PMID:27065531

  3. Effects of a continuous lateral turning device on pressure relief.

    PubMed

    Do, Nam Ho; Kim, Deog Young; Kim, Jung-Hoon; Choi, Jong Hyun; Joo, So Young; Kang, Na Kyung; Baek, Yoon Su

    2016-01-01

    [Purpose] The purpose of this study was to examine the pressure-relieving effects of a continuous lateral turning device on common pressure ulcer sites. [Subjects] Twenty-four healthy adults participated. [Methods] The design of our continuous lateral turning device was motivated by the need for an adequate pressure-relieving device for immobile and/or elderly people. The procedure of manual repositioning is embodied in our continuous lateral turning device. The interface pressure and time were measured, and comfort grade was evaluated during sessions of continuous lateral turning at 0°, 15°, 30°, and 45°. We quantified the pressure-relieving effect using peak pressure, mean pressure, and pressure time integration. [Results] Participants demonstrated pressure time integration values below the pressure-time threshold at 15°, 30°, and 45° at all the common pressure ulcer sites. Moreover, the most effective angles for pressure relief at the common pressure ulcer sites were 30° at the occiput, 15° at the left scapula, 45° at the right scapula, 45° at the sacrum, 15° at the right heel, and 30° at the left heel. However, angles greater than 30° induced discomfort. [Conclusion] Continuous lateral turning with our specially designed device effectively relieved the pressure of targeted sites. Moreover, the suggested angles of continuous lateral turning can be used to relieve pressure at targeted sites.

  4. 74. LIQUID NITROGEN TANK, REGULATOR VALVES, AND PRESSURE GAUGES FOR ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    74. LIQUID NITROGEN TANK, REGULATOR VALVES, AND PRESSURE GAUGES FOR LIQUID NITROGEN PUMPING STATION - Vandenberg Air Force Base, Space Launch Complex 3, Launch Pad 3 East, Napa & Alden Roads, Lompoc, Santa Barbara County, CA

  5. Detail view of valve mechanisms and goverenor on high pressure ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Detail view of valve mechanisms and goverenor on high pressure stage engine of unit 43. - Burnsville Natural Gas Pumping Station, Saratoga Avenue between Little Kanawha River & C&O Railroad line, Burnsville, Braxton County, WV

  6. Pressure-relief and methane production performance of pressure relief gas extraction technology in the longwall mining

    NASA Astrophysics Data System (ADS)

    Zhang, Cun; Tu, Shihao; Chen, Min; Zhang, Lei

    2017-02-01

    Pressure relief gas extraction technology (PRGET) has been successfully implemented at many locations as a coal mine methane exploitation and outburst prevention technology. Comprehensive PRGET including gob gas venthole (GGV), crossing seam drilling hole (CSDH), large diameter horizontal long drilling hole (LDHLDH) and buried pipe for extraction (BPE) have been used to extract abundant pressure-relief methane (PRM) during protective coal seam mining; these techniques mitigated dangers associated with coal and gas outbursts in 13-1 coal seam mining in the Huainan coalfield. These extraction technologies can ensure safe protective seam mining and effectively extract coal and gas. This article analyses PRGET production performance and verifies it with the field measurement. The results showed that PRGET drilling to extract PRM from the protected coal seam significantly reduced methane emissions from a longwall ventilation system and produced highly efficient extraction. Material balance analyses indicated a significant decrease in gas content and pressure in the protected coal seam, from 8.78 m3 t-1 and 4.2 MPa to 2.34 m3 t-1 and 0.285 MPa, respectively. The field measurement results of the residual gas content in protected coal seam (13-1 coal seam) indicated the reliability of the material balance analyses and the pressure relief range of PRGET in the protected coal seam is obtained.

  7. 30 CFR 18.28 - Devices for pressure relief, ventilation, or drainage.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Construction and Design Requirements § 18.28 Devices for pressure relief, ventilation, or drainage. (a) Devices... 30 Mineral Resources 1 2013-07-01 2013-07-01 false Devices for pressure relief, ventilation, or... metal will prevent discharge of flame in explosion tests. (b) Devices for pressure relief,...

  8. 30 CFR 18.28 - Devices for pressure relief, ventilation, or drainage.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Construction and Design Requirements § 18.28 Devices for pressure relief, ventilation, or drainage. (a) Devices... 30 Mineral Resources 1 2011-07-01 2011-07-01 false Devices for pressure relief, ventilation, or... metal will prevent discharge of flame in explosion tests. (b) Devices for pressure relief,...

  9. 30 CFR 18.28 - Devices for pressure relief, ventilation, or drainage.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Construction and Design Requirements § 18.28 Devices for pressure relief, ventilation, or drainage. (a) Devices... 30 Mineral Resources 1 2012-07-01 2012-07-01 false Devices for pressure relief, ventilation, or... metal will prevent discharge of flame in explosion tests. (b) Devices for pressure relief,...

  10. 30 CFR 18.28 - Devices for pressure relief, ventilation, or drainage.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Construction and Design Requirements § 18.28 Devices for pressure relief, ventilation, or drainage. (a) Devices... 30 Mineral Resources 1 2014-07-01 2014-07-01 false Devices for pressure relief, ventilation, or... metal will prevent discharge of flame in explosion tests. (b) Devices for pressure relief,...

  11. 40 CFR 63.1030 - Pressure relief devices in gas and vapor service standards.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... § 63.1030 Pressure relief devices in gas and vapor service standards. (a) Compliance schedule. The... section, each pressure relief device in gas and vapor service shall be operated with an instrument reading... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Pressure relief devices in gas...

  12. 40 CFR 63.1030 - Pressure relief devices in gas and vapor service standards.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... § 63.1030 Pressure relief devices in gas and vapor service standards. (a) Compliance schedule. The... section, each pressure relief device in gas and vapor service shall be operated with an instrument reading... 40 Protection of Environment 11 2012-07-01 2012-07-01 false Pressure relief devices in gas...

  13. 40 CFR 264.1054 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... relief devices in gas/vapor service. (a) Except during pressure releases, each pressure relief device in... 40 Protection of Environment 26 2014-07-01 2014-07-01 false Standards: Pressure relief devices in gas/vapor service. 264.1054 Section 264.1054 Protection of Environment ENVIRONMENTAL PROTECTION...

  14. 40 CFR 63.1011 - Pressure relief devices in gas and vapor service standards.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Pressure relief devices in gas and vapor service standards. (a) Compliance schedule. The owner or operator... section, each pressure relief device in gas or vapor service shall be operated with an instrument reading... 40 Protection of Environment 11 2012-07-01 2012-07-01 false Pressure relief devices in gas...

  15. 40 CFR 264.1054 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... relief devices in gas/vapor service. (a) Except during pressure releases, each pressure relief device in... 40 Protection of Environment 25 2010-07-01 2010-07-01 false Standards: Pressure relief devices in gas/vapor service. 264.1054 Section 264.1054 Protection of Environment ENVIRONMENTAL PROTECTION...

  16. 40 CFR 63.1030 - Pressure relief devices in gas and vapor service standards.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... § 63.1030 Pressure relief devices in gas and vapor service standards. (a) Compliance schedule. The... section, each pressure relief device in gas and vapor service shall be operated with an instrument reading... 40 Protection of Environment 10 2011-07-01 2011-07-01 false Pressure relief devices in gas...

  17. 40 CFR 264.1054 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... relief devices in gas/vapor service. (a) Except during pressure releases, each pressure relief device in... 40 Protection of Environment 27 2012-07-01 2012-07-01 false Standards: Pressure relief devices in gas/vapor service. 264.1054 Section 264.1054 Protection of Environment ENVIRONMENTAL PROTECTION...

  18. 40 CFR 63.1030 - Pressure relief devices in gas and vapor service standards.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... § 63.1030 Pressure relief devices in gas and vapor service standards. (a) Compliance schedule. The... section, each pressure relief device in gas and vapor service shall be operated with an instrument reading... 40 Protection of Environment 11 2013-07-01 2013-07-01 false Pressure relief devices in gas...

  19. 40 CFR 63.1030 - Pressure relief devices in gas and vapor service standards.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... § 63.1030 Pressure relief devices in gas and vapor service standards. (a) Compliance schedule. The... section, each pressure relief device in gas and vapor service shall be operated with an instrument reading... 40 Protection of Environment 11 2014-07-01 2014-07-01 false Pressure relief devices in gas...

  20. 40 CFR 264.1054 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... relief devices in gas/vapor service. (a) Except during pressure releases, each pressure relief device in... 40 Protection of Environment 27 2013-07-01 2013-07-01 false Standards: Pressure relief devices in gas/vapor service. 264.1054 Section 264.1054 Protection of Environment ENVIRONMENTAL PROTECTION...

  1. 40 CFR 63.1011 - Pressure relief devices in gas and vapor service standards.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Pressure relief devices in gas and vapor service standards. (a) Compliance schedule. The owner or operator... section, each pressure relief device in gas or vapor service shall be operated with an instrument reading... 40 Protection of Environment 10 2011-07-01 2011-07-01 false Pressure relief devices in gas...

  2. 40 CFR 264.1054 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... relief devices in gas/vapor service. (a) Except during pressure releases, each pressure relief device in... 40 Protection of Environment 26 2011-07-01 2011-07-01 false Standards: Pressure relief devices in gas/vapor service. 264.1054 Section 264.1054 Protection of Environment ENVIRONMENTAL PROTECTION...

  3. 40 CFR 63.1011 - Pressure relief devices in gas and vapor service standards.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Pressure relief devices in gas and vapor service standards. (a) Compliance schedule. The owner or operator... section, each pressure relief device in gas or vapor service shall be operated with an instrument reading... 40 Protection of Environment 10 2010-07-01 2010-07-01 false Pressure relief devices in gas...

  4. 40 CFR 63.1011 - Pressure relief devices in gas and vapor service standards.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Pressure relief devices in gas and vapor service standards. (a) Compliance schedule. The owner or operator... section, each pressure relief device in gas or vapor service shall be operated with an instrument reading... 40 Protection of Environment 11 2013-07-01 2013-07-01 false Pressure relief devices in gas...

  5. 40 CFR 63.1011 - Pressure relief devices in gas and vapor service standards.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Pressure relief devices in gas and vapor service standards. (a) Compliance schedule. The owner or operator... section, each pressure relief device in gas or vapor service shall be operated with an instrument reading... 40 Protection of Environment 11 2014-07-01 2014-07-01 false Pressure relief devices in gas...

  6. Effects of pressure and temperature on gate valve unwedging

    SciTech Connect

    Damerell, P.S.; Harrison, D.H.; Hayes, P.W.; Simons, J.W.; Walker, T.A.

    1996-12-01

    The stem thrust required to unwedge a gate valve is influenced by the pressure and temperature when the valve is closed and by the changes in these conditions between closure and opening. {open_quotes}Pressure locking{close_quotes} and {open_quotes}thermal binding{close_quotes} refer to situations where pressure and temperature effects cause the unwedging load to be much higher than normal. A model of these phenomena has been developed. Wedging (closure) is modeled as developing an {open_quotes}interference{close_quotes} between the disk and its seat rings in the valve. The effects of pressure and temperature are analyzed to determine the change in this disk-to-seat {open_quotes}interference{close_quotes}. Flexibilities, of the disk, body, stem and yoke strongly influence the unwedging thrust. Calculations and limited comparisons to data have been performed for a range of valve designs and scenarios. Pressure changes can increase the unwedging load when there is either a uniform pressure decrease, or a situation where the bonnet pressure exceeds the pressures in the adjacent piping. Temperature changes can increase the unwedging load when: (1) valve closure at elevated system temperature produces a delayed stem expansion, (2) a temperature increase after closure produces a bonnet pressure increase, or (3) a temperature change after closure produces an increase in the disk-to-seat {open_quotes}interference{close_quotes} or disk-to-seat friction.

  7. Pressure locking and thermal binding of gate valves

    SciTech Connect

    Kelly, E.M.

    1996-12-01

    Pressure locking and thermal binding represent potential common mode failure mechanisms that can cause safety-related power-operated gate valves to fail in the closed position, thus rendering redundant safety-related systems incapable of performing their safety functions. Supplement 6 to Generic Letter 89-10, {open_quotes}Safety-Related Motor-Operated Gate Valve Testing and Surveillance,{close_quotes} provided an acceptable approach to addressing pressure locking and thermal binding of gate valves. More recently, the NRC has issued Generic Letter 95-07, {open_quotes}Pressure Locking and Thermal Binding of Safety-Related Power-Operated Gate Valves,{close_quotes} to request that licensees take certain actions to ensure that safety-related power-operated gate valves that are susceptible to pressure locking or thermal binding are capable of performing their safety functions within the current licensing bases. Over the past two years, several plants in Region I determined that valves in certain systems were potentially susceptible to pressure locking and thermal binding, and have taken various corrective actions. The NRC Region I Systems Engineering Branch has been actively involved in the inspection of licensee actions in response to the pressure locking and thermal binding issue. Region I continues to maintain an active involvement in this area, including participation with the Office of Nuclear Reactor Regulation in reviewing licensee responses to Generic Letter 95-07.

  8. Study of fluid parameters in high pressure descaling valves

    NASA Astrophysics Data System (ADS)

    Adhikari, Param; Panta, Yogendra

    2012-11-01

    Our work is focused on the high pressure valves used for descaling purposes in steel mills. A reverse flow operation was set in one of such valves due to piping constraints. Computational approaches are being utilized to understand the fluid phenomena at such high pressures. Though the valve geometry accounts for the complete fluid flow path, a study has been initiated from an axisymmetric model of the valve core. The highly energized fluid from the descaling pump sets off a static pressure of 5000 psi at the valve inlet. It is responsible for continuous fluid flow rate of up to 208 gpm for fully open position. A Shear Stress Transport turbulence model is utilized to study pressure at nearly closed position of the poppet part while Renormalization Group Turbulence model is compared with Shear Stress Transport turbulence model for full opening position. A very low pressure developed below the poppet seat suggests the onset of cavitation zones which may lead to leakage. A full 3D model is studied after a complete studies of fluid phenomenon in the axisymmetric geometry. Using ANSYS Fluent, a commercial CFD software package, the poppet valve assembly was processed for modeling, meshing and setting up of physical parameters. Computational results show the cavitation intensities higher at small openings than at larger openings which is further verified by literature research and currently comparing with experiments.

  9. 46 CFR 64.69 - Location of the pressure relief device.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Location of the pressure relief device. 64.69 Section 64.69 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs §...

  10. 46 CFR 64.69 - Location of the pressure relief device.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Location of the pressure relief device. 64.69 Section 64.69 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs §...

  11. 46 CFR 64.69 - Location of the pressure relief device.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Location of the pressure relief device. 64.69 Section 64.69 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs §...

  12. 46 CFR 64.69 - Location of the pressure relief device.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Location of the pressure relief device. 64.69 Section 64.69 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs §...

  13. 46 CFR 64.69 - Location of the pressure relief device.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Location of the pressure relief device. 64.69 Section 64.69 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs §...

  14. Ventricular pressure slope and bileaflet mechanical heart valve closure.

    PubMed

    Wu, Z J; Hwang, N H

    1995-01-01

    The maximum left ventricular pressure slope (dP/dt) value has been used by several investigators as the criterion for studying mitral valve closure. In this article, the relationship between the ventricular pressure slope (dP/dt) and the leaflet closing behavior of bileaflet mechanical heart valves (BMV) is investigated. Two current BMVs, the St. Jude Medical 29 mm and CarboMedics 29 mm, installed in the mitral position of a mock circulatory pulsatile flow loop were used as the study model. Under simulated physiologic pressures and flow conditions, the experiment was conducted at 70, 90, and 120 beats/min with corresponding flow rates of 5.0, 6.0, and 7.5 liters/min, respectively. A laser sweeping technique was used to monitor the leaflet closing motion within the last 3 degrees excursion at valve closure. A modified dual beam laser sweeping technique system was used to register the difference of leaflet/housing impact time between the two BMV closing leaflets in asynchronous closure. Common BMV asynchronous closures were found in both BMVs at all three heart rates tested. The second closing leaflet was found to always close at higher velocity than the first. Simultaneous measurements of the ventricular pressure (Pv) and the leaflet closing time showed that Pv exhibited three stage characteristics. In the first stage, Pv gradually increased as the ventricle was filled. A sudden rise of Pv occurred immediately after closing of the first leaflet. The maximum dp/dt occurred in the third stage after closure of both BMV leaflets. The BMV closing behavior and the corresponding Pv pattern were found to depend strongly upon valve type and heart rate. The time averaged ventricular pressure slope (dp/dt) values at 70, 90, and 120 beats/min were about 40, 70, and 150 mmHg/sec for the St. Jude Medical valve and 40, 105, and 205 for the CarboMedics valve during the first closing stage. The maximum dp/dt values were 2670, 4350, and 5000 mmHg/sec for the St. Jude Medical valve

  15. 40 CFR 60.482-4a - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Standards: Pressure relief devices in gas/vapor service. (a) Except during pressure releases, each pressure... 40 Protection of Environment 6 2011-07-01 2011-07-01 false Standards: Pressure relief devices in gas/vapor service. 60.482-4a Section 60.482-4a Protection of Environment ENVIRONMENTAL...

  16. 40 CFR 63.165 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Standards: Pressure relief devices in gas/vapor service. (a) Except during pressure releases, each pressure... 40 Protection of Environment 10 2014-07-01 2014-07-01 false Standards: Pressure relief devices in gas/vapor service. 63.165 Section 63.165 Protection of Environment ENVIRONMENTAL PROTECTION...

  17. 40 CFR 60.482-4a - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Standards: Pressure relief devices in gas/vapor service. (a) Except during pressure releases, each pressure... 40 Protection of Environment 7 2012-07-01 2012-07-01 false Standards: Pressure relief devices in gas/vapor service. 60.482-4a Section 60.482-4a Protection of Environment ENVIRONMENTAL...

  18. 40 CFR 63.165 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... Standards: Pressure relief devices in gas/vapor service. (a) Except during pressure releases, each pressure... 40 Protection of Environment 9 2011-07-01 2011-07-01 false Standards: Pressure relief devices in gas/vapor service. 63.165 Section 63.165 Protection of Environment ENVIRONMENTAL PROTECTION...

  19. 40 CFR 60.482-4a - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... Standards: Pressure relief devices in gas/vapor service. (a) Except during pressure releases, each pressure... 40 Protection of Environment 7 2014-07-01 2014-07-01 false Standards: Pressure relief devices in gas/vapor service. 60.482-4a Section 60.482-4a Protection of Environment ENVIRONMENTAL...

  20. 40 CFR 63.165 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... Standards: Pressure relief devices in gas/vapor service. (a) Except during pressure releases, each pressure... 40 Protection of Environment 10 2012-07-01 2012-07-01 false Standards: Pressure relief devices in gas/vapor service. 63.165 Section 63.165 Protection of Environment ENVIRONMENTAL PROTECTION...

  1. 40 CFR 60.482-4a - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Standards: Pressure relief devices in gas/vapor service. (a) Except during pressure releases, each pressure... 40 Protection of Environment 7 2013-07-01 2013-07-01 false Standards: Pressure relief devices in gas/vapor service. 60.482-4a Section 60.482-4a Protection of Environment ENVIRONMENTAL...

  2. 40 CFR 63.165 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... Standards: Pressure relief devices in gas/vapor service. (a) Except during pressure releases, each pressure... 40 Protection of Environment 10 2013-07-01 2013-07-01 false Standards: Pressure relief devices in gas/vapor service. 63.165 Section 63.165 Protection of Environment ENVIRONMENTAL PROTECTION...

  3. 40 CFR 63.165 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Standards: Pressure relief devices in gas/vapor service. (a) Except during pressure releases, each pressure... 40 Protection of Environment 9 2010-07-01 2010-07-01 false Standards: Pressure relief devices in gas/vapor service. 63.165 Section 63.165 Protection of Environment ENVIRONMENTAL PROTECTION...

  4. 40 CFR 60.482-4a - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... Standards: Pressure relief devices in gas/vapor service. (a) Except during pressure releases, each pressure... 40 Protection of Environment 6 2010-07-01 2010-07-01 false Standards: Pressure relief devices in gas/vapor service. 60.482-4a Section 60.482-4a Protection of Environment ENVIRONMENTAL...

  5. Pressure tracking control of vehicle ABS using piezo valve modulator

    NASA Astrophysics Data System (ADS)

    Jeon, Juncheol; Choi, Seung-Bok

    2011-03-01

    This paper presents a wheel slip control for the ABS(anti-lock brake system) of a passenger vehicle using a controllable piezo valve modulator. The ABS is designed to optimize for braking effectiveness and good steerability. As a first step, the principal design parameters of the piezo valve and pressure modulator are appropriately determined by considering the braking pressure variation during the ABS operation. The proposed piezo valve consists of a flapper, pneumatic circuit and a piezostack actuator. In order to get wide control range of the pressure, the pressure modulator is desired. The modulator consists of a dual-type cylinder filled with different substances (fluid and gas) and a piston rod moving vertical axis to transmit the force. Subsequently, a quarter car wheel slip model is formulated and integrated with the governing equation of the piezo valve modulator. A sliding mode controller to achieve the desired slip rate is then designed and implemented. Braking control performances such as brake pressure and slip rate are evaluated via computer simulations.

  6. Workshop on gate valve pressure locking and thermal binding

    SciTech Connect

    Brown, E.J.

    1995-07-01

    The purpose of the Workshop on Gate Valve Pressure Locking and Thermal Binding was to discuss pressure locking and thermal binding issues that could lead to inoperable gate valves in both boiling water and pressurized water reactors. The goal was to foster exchange of information to develop the technical bases to understand the phenomena, identify the components that are susceptible, discuss actual events, discuss the safety significance, and illustrate known corrective actions that can prevent or limit the occurrence of pressure locking or thermal binding. The presentations were structured to cover U.S. Nuclear Regulatory Commission staff evaluation of operating experience and planned regulatory activity; industry discussions of specific events, including foreign experience, and efforts to determine causes and alleviate the affects; and valve vendor experience and recommended corrective action. The discussions indicated that identifying valves susceptible to pressure locking and thermal binding was a complex process involving knowledge of components, systems, and plant operations. The corrective action options are varied and straightforward.

  7. 40 CFR 61.242-4 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... devices in gas/vapor service. (a) Except during pressure releases, each pressure relief device in gas... 40 Protection of Environment 8 2011-07-01 2011-07-01 false Standards: Pressure relief devices in gas/vapor service. 61.242-4 Section 61.242-4 Protection of Environment ENVIRONMENTAL PROTECTION...

  8. 40 CFR 61.242-4 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... devices in gas/vapor service. (a) Except during pressure releases, each pressure relief device in gas... 40 Protection of Environment 9 2014-07-01 2014-07-01 false Standards: Pressure relief devices in gas/vapor service. 61.242-4 Section 61.242-4 Protection of Environment ENVIRONMENTAL PROTECTION...

  9. 40 CFR 61.242-4 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... devices in gas/vapor service. (a) Except during pressure releases, each pressure relief device in gas... 40 Protection of Environment 9 2013-07-01 2013-07-01 false Standards: Pressure relief devices in gas/vapor service. 61.242-4 Section 61.242-4 Protection of Environment ENVIRONMENTAL PROTECTION...

  10. 40 CFR 61.242-4 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... devices in gas/vapor service. (a) Except during pressure releases, each pressure relief device in gas... 40 Protection of Environment 9 2012-07-01 2012-07-01 false Standards: Pressure relief devices in gas/vapor service. 61.242-4 Section 61.242-4 Protection of Environment ENVIRONMENTAL PROTECTION...

  11. 40 CFR 61.242-4 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... devices in gas/vapor service. (a) Except during pressure releases, each pressure relief device in gas... 40 Protection of Environment 8 2010-07-01 2010-07-01 false Standards: Pressure relief devices in gas/vapor service. 61.242-4 Section 61.242-4 Protection of Environment ENVIRONMENTAL PROTECTION...

  12. Importance of pressure reducing valves (PRVs) in water supply networks.

    NASA Astrophysics Data System (ADS)

    Signoreti, R. O. S.; Camargo, R. Z.; Canno, L. M.; Pires, M. S. G.; Ribeiro, L. C. L. J.

    2016-08-01

    Challenged with the high rate of leakage from water supply systems, these managers are committed to identify control mechanisms. In order to standardize and control the pressure Pressure Reducing Valves (VRP) are installed in the supply network, shown to be more effective and provide a faster return for the actual loss control measures. It is known that the control pressure is while controlling the occurrence of leakage. Usually the network is sectored in areas defined by pressure levels according to its topography, once inserted the VRP in the same system will limit the downstream pressure. This work aims to show the importance of VRP as loss reduction for tool.

  13. Digital valve for high pressure high flow applications

    NASA Astrophysics Data System (ADS)

    Badescu, Mircea; Sherrit, Stewart; Lewis, Derek; Bao, Xiaoqi; Bar-Cohen, Yoseph; Hall, Jeffery L.

    2016-04-01

    To address the challenges, which are involved with the development of flow control valves that can meet high demand requirements such as high pressure, high flow rate, limited power and limited space, the authors have conceived a novel design configuration. This design consists of a digitalized flow control valve with multipath and multistage pressure reduction structures. Specifically, the valve is configured as a set of parallel flow paths from the inlet to the outlet. A choke valve controls the total flow rate by digitally opening different paths or different combination of the paths. Each path is controlled by a poppet cap valve basically operated in on-off states. The number of flow states is 2N where N is the number of flow paths. To avoid erosion from sand in the fluid and high speed flow, the seal area of the poppet cap valve is located at a distance from the flow inlet away from the high speed flow and the speed is controlled to stay below a predefined erosion safe limit. The path is a multistage structure composed of a set of serial nozzles-expansion chambers that equally distribute the total pressure drop to each stage. The pressure drop of each stage and, therefore, the flow speed at the nozzles and expansion chambers is controlled by the number of stages. The paths have relatively small cross section and could be relatively long for large number of stages and still fit in a strict annular space limit. The paper will present the design configuration, analysis and preliminary test results.

  14. Reed Valve Regulates Welding Back-Purge Pressure

    NASA Technical Reports Server (NTRS)

    Coby, J. Ben, Jr.; Weeks, Jack L.

    1991-01-01

    Simple modification yields welds of better quality. Reed valve halves fluctuations in pressure in back-purge chamber attached to workpiece undergoing keyhole plasma arc welding. Identical to one used in fuel system of two-cycle gasoline engine. Backbead smoother, and weld penetrates more uniformly.

  15. 46 CFR 64.67 - Shutoff valve.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Shutoff valve. 64.67 Section 64.67 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.67 Shutoff valve. A shutoff...

  16. 46 CFR 64.67 - Shutoff valve.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Shutoff valve. 64.67 Section 64.67 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.67 Shutoff valve. A shutoff...

  17. 46 CFR 64.67 - Shutoff valve.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Shutoff valve. 64.67 Section 64.67 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.67 Shutoff valve. A shutoff...

  18. 46 CFR 64.67 - Shutoff valve.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Shutoff valve. 64.67 Section 64.67 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.67 Shutoff valve. A shutoff...

  19. 46 CFR 64.67 - Shutoff valve.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Shutoff valve. 64.67 Section 64.67 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) MARINE ENGINEERING MARINE PORTABLE TANKS AND CARGO HANDLING SYSTEMS Pressure Relief Devices and Vacuum Relief Devices for MPTs § 64.67 Shutoff valve. A shutoff...

  20. 46 CFR 154.452 - External pressure.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 5 2012-10-01 2012-10-01 false External pressure. 154.452 Section 154.452 Shipping... Independent Tank Type C and Process Pressure Vessels § 154.452 External pressure. The design external pressure...) for tanks without a vacuum relief valve. P2=0, or the pressure relief valve setting for an...

  1. 46 CFR 154.452 - External pressure.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 5 2014-10-01 2014-10-01 false External pressure. 154.452 Section 154.452 Shipping... Independent Tank Type C and Process Pressure Vessels § 154.452 External pressure. The design external pressure...) for tanks without a vacuum relief valve. P2=0, or the pressure relief valve setting for an...

  2. 46 CFR 154.452 - External pressure.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 5 2011-10-01 2011-10-01 false External pressure. 154.452 Section 154.452 Shipping... Independent Tank Type C and Process Pressure Vessels § 154.452 External pressure. The design external pressure...) for tanks without a vacuum relief valve. P2=0, or the pressure relief valve setting for an...

  3. 46 CFR 154.452 - External pressure.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 5 2010-10-01 2010-10-01 false External pressure. 154.452 Section 154.452 Shipping... Independent Tank Type C and Process Pressure Vessels § 154.452 External pressure. The design external pressure...) for tanks without a vacuum relief valve. P2=0, or the pressure relief valve setting for an...

  4. 46 CFR 154.452 - External pressure.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 5 2013-10-01 2013-10-01 false External pressure. 154.452 Section 154.452 Shipping... Independent Tank Type C and Process Pressure Vessels § 154.452 External pressure. The design external pressure...) for tanks without a vacuum relief valve. P2=0, or the pressure relief valve setting for an...

  5. 40 CFR 65.111 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ...: Pressure relief devices in gas/vapor service. (a) Compliance schedule. The owner or operator shall comply... 40 Protection of Environment 15 2011-07-01 2011-07-01 false Standards: Pressure relief devices in gas/vapor service. 65.111 Section 65.111 Protection of Environment ENVIRONMENTAL PROTECTION...

  6. 40 CFR 65.111 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ...: Pressure relief devices in gas/vapor service. (a) Compliance schedule. The owner or operator shall comply... 40 Protection of Environment 15 2010-07-01 2010-07-01 false Standards: Pressure relief devices in gas/vapor service. 65.111 Section 65.111 Protection of Environment ENVIRONMENTAL PROTECTION...

  7. 40 CFR 65.111 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ...: Pressure relief devices in gas/vapor service. (a) Compliance schedule. The owner or operator shall comply... 40 Protection of Environment 16 2012-07-01 2012-07-01 false Standards: Pressure relief devices in gas/vapor service. 65.111 Section 65.111 Protection of Environment ENVIRONMENTAL PROTECTION...

  8. 40 CFR 65.111 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ...: Pressure relief devices in gas/vapor service. (a) Compliance schedule. The owner or operator shall comply... 40 Protection of Environment 16 2014-07-01 2014-07-01 false Standards: Pressure relief devices in gas/vapor service. 65.111 Section 65.111 Protection of Environment ENVIRONMENTAL PROTECTION...

  9. 40 CFR 65.111 - Standards: Pressure relief devices in gas/vapor service.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ...: Pressure relief devices in gas/vapor service. (a) Compliance schedule. The owner or operator shall comply... 40 Protection of Environment 16 2013-07-01 2013-07-01 false Standards: Pressure relief devices in gas/vapor service. 65.111 Section 65.111 Protection of Environment ENVIRONMENTAL PROTECTION...

  10. 49 CFR 195.264 - Impoundment, protection against entry, normal/emergency venting or pressure/vacuum relief for...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... relief venting must be provided for each atmospheric pressure breakout tank. Pressure/vacuum-relieving... specified: (1) Normal/emergency relief venting installed on atmospheric pressure tanks built to API... relief venting installed on atmospheric pressure tanks (such as those built to API Standard 650 or...

  11. 49 CFR 195.264 - Impoundment, protection against entry, normal/emergency venting or pressure/vacuum relief for...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... relief venting must be provided for each atmospheric pressure breakout tank. Pressure/vacuum-relieving... specified: (1) Normal/emergency relief venting installed on atmospheric pressure tanks built to API... relief venting installed on atmospheric pressure tanks (such as those built to API Standard 650 or...

  12. 49 CFR 195.264 - Impoundment, protection against entry, normal/emergency venting or pressure/vacuum relief for...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... relief venting must be provided for each atmospheric pressure breakout tank. Pressure/vacuum-relieving... specified: (1) Normal/emergency relief venting installed on atmospheric pressure tanks built to API... relief venting installed on atmospheric pressure tanks (such as those built to API Standard 650 or...

  13. 49 CFR 195.264 - Impoundment, protection against entry, normal/emergency venting or pressure/vacuum relief for...

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... relief venting must be provided for each atmospheric pressure breakout tank. Pressure/vacuum-relieving... specified: (1) Normal/emergency relief venting installed on atmospheric pressure tanks built to API... relief venting installed on atmospheric pressure tanks (such as those built to API Standard 650 or...

  14. 49 CFR 195.264 - Impoundment, protection against entry, normal/emergency venting or pressure/vacuum relief for...

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... relief venting must be provided for each atmospheric pressure breakout tank. Pressure/vacuum-relieving... specified: (1) Normal/emergency relief venting installed on atmospheric pressure tanks built to API... relief venting installed on atmospheric pressure tanks (such as those built to API Standard 650 or...

  15. System for detecting operating errors in a variable valve timing engine using pressure sensors

    DOEpatents

    Wiles, Matthew A.; Marriot, Craig D

    2013-07-02

    A method and control module includes a pressure sensor data comparison module that compares measured pressure volume signal segments to ideal pressure volume segments. A valve actuation hardware remedy module performs a hardware remedy in response to comparing the measured pressure volume signal segments to the ideal pressure volume segments when a valve actuation hardware failure is detected.

  16. 46 CFR 52.01-120 - Safety valves and safety relief valves (modifies PG-67 through PG-73).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... than 51mm (2 in.) NPS. (3) On river steam vessels whose boilers are connected in batteries without means of isolating one boiler from another, each battery of boilers shall be treated as a single boiler... weighted safety valves now installed may be continued in use and may be repaired, but when renewals...

  17. 46 CFR 52.01-120 - Safety valves and safety relief valves (modifies PG-67 through PG-73).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... than 51mm (2 in.) NPS. (3) On river steam vessels whose boilers are connected in batteries without means of isolating one boiler from another, each battery of boilers shall be treated as a single boiler... weighted safety valves now installed may be continued in use and may be repaired, but when renewals...

  18. ESTIMATED SIL LEVELS AND RISK COMPARISONS FOR RELIEF VALVES AS A FUNCTION OF TIME-IN-SERVICE

    SciTech Connect

    Harris, S.

    2012-03-26

    Risk-based inspection methods enable estimation of the probability of spring-operated relief valves failing on demand at the United States Department of Energy's Savannah River Site (SRS) in Aiken, South Carolina. The paper illustrates an approach based on application of the Frechet and Weibull distributions to SRS and Center for Chemical Process Safety (CCPS) Process Equipment Reliability Database (PERD) proof test results. The methodology enables the estimation of ANSI/ISA-84.00.01 Safety Integrity Levels (SILs) as well as the potential change in SIL level due to modification of the maintenance schedule. Current SRS practices are reviewed and recommendations are made for extending inspection intervals. The paper compares risk-based inspection with specific SILs as maintenance intervals are adjusted. Groups of valves are identified in which maintenance times can be extended as well as different groups in which an increased safety margin may be needed.

  19. Pressure Relief Devices for High-Pressure Gaseous Storage Systems: Applicability to Hydrogen Technology

    SciTech Connect

    Kostival, A.; Rivkin, C.; Buttner, W.; Burgess, R.

    2013-11-01

    Pressure relief devices (PRDs) are viewed as essential safety measures for high-pressure gas storage and distribution systems. These devices are used to prevent the over-pressurization of gas storage vessels and distribution equipment, except in the application of certain toxic gases. PRDs play a critical role in the implementation of most high-pressure gas storage systems and anyone working with these devices should understand their function so they can be designed, installed, and maintained properly to prevent any potentially dangerous or fatal incidents. As such, the intention of this report is to introduce the reader to the function of the common types of PRDs currently used in industry. Since high-pressure hydrogen gas storage systems are being developed to support the growing hydrogen energy infrastructure, several recent failure incidents, specifically involving hydrogen, will be examined to demonstrate the results and possible mechanisms of a device failure. The applicable codes and standards, developed to minimize the risk of failure for PRDs, will also be reviewed. Finally, because PRDs are a critical component for the development of a successful hydrogen energy infrastructure, important considerations for pressure relief devices applied in a hydrogen gas environment will be explored.

  20. 77 FR 54839 - Clarification of Submission of Requests for Relief or Alternatives From the Regulatory...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-09-06

    ... Pressure Vessel Code (ASME BPV Code) and Code for Operation and Maintenance of Nuclear Power Plants (OM... evaluation. Provide the ASME BPV or OM Code examination or test requirements for the pump(s), valve(s), weld... specific pump(s), valve(s), weld(s), or component(s) for which the relief or alternative is requested....

  1. Transient pressure signals in mechanical heart valve cavitation.

    PubMed

    Wu, Z J; Slonin, J H; Hwang, N H

    1996-01-01

    The purpose of this investigation was to establish a correlation between mechanical heart valve (MHV) cavitation and transient pressure (TP) signals at MHV closure. This correlation may suggest a possible method to detect in vivo MHV cavitation. In a pulsatile mock flow loop, a study was performed to measure TP and observe cavitation bubble inception at MHV closure under simulated physiologic ventricular and aortic pressures at heart rates of 70, 90, 120, and 140 beats/min with corresponding cardiac outputs of 5.0, 6.0, 7.5, and 8.5 L/min, respectively. The experimental study included two bileaflet MHV prostheses: 1) St. Jude Medical 31 mm and 2) Carbomedics 31 mm. High fidelity piezo-electric pressure transducers were used to measure TP immediately before and after the valve leaflet/housing impact. A stroboscopic lighting imaging technique was developed to capture cavitation bubbles on the MHV inflow surfaces at selected time delays ranging from 25 microseconds to 1 ms after the leaflet/housing impact. The TP traces measured 10 mm away from the valve leaflet tip showed a large pressure reduction peak at the leaflet/housing impact, and subsequent high frequency pressure oscillations (HPOs) while the cavitation bubbles were observed. The occurrence of cavitation bubbles and HPO bursts were found to be random on a beat by beat basis. However, the amplitude of the TP reduction, the intensity of the cavitation bubble (size and number), and the intensity of HPO were found to increase with the test heart rate. A correlation between the MHV cavitation bubbles and the HPO burst was positively established. Power spectrum analysis of the TP signals further showed that the frequency of the HPO (cavitation bubble collapse pressures) ranged from 100 to 450 kHz.

  2. ENVIRONMENTAL TECHNOLOGY VERIFICATION REPORT THE PROTECTOSEAL COMPANY PIN-TECH BUBBLE TIGHT < 500 PPM RELIEF VENT

    EPA Science Inventory

    The Environmental Technology Verification report discusses the technology and performance of a pressure relief valve for protection of storage tanks that operate at pressures of 15 psig or less. Four Pin-Tech Bubble Tight <500 ppm Relief Vent valves manufactured by the Protectose...

  3. Innovative, High-Pressure, Cryogenic Control Valve: Short Face-to-Face, Reduced Cost

    NASA Technical Reports Server (NTRS)

    Wilkes, Karlin; Larsen, Ed; McCourt, Jackson

    2003-01-01

    A control valve that can throttle high-pressure cryogenic fluid embodies several design features that distinguish it over conventional valves designed for similar applications. Field and design engineers worked together to create a valve that would simplify installation, trim changes, and maintenance, thus reducing overall cost. The seals and plug stem packing were designed to perform optimally in cryogenic temperature ranges. Unlike conventional high-pressure cryogenic valves, the trim size can be changed independent of the body.

  4. The efficacy of pressure relief maneuvers in spinal cord injury patients, a clinical study

    NASA Astrophysics Data System (ADS)

    Ho, Thuan; Nguyen, Ahn Thu; Lichy, Alison; Groah, Suzanne; Ramella-Roman, Jessica C.

    2014-02-01

    Pressure reliefs are recommended to wheelchair bound individuals to control and minimize skin damage. To this date recommendation on duration and intervals between pressure reliefs is not clear. Recent studies have shown a relationship between reduction in tissue perfusion and oxygenation due to pressure and skin pathophysiologic changes. We have developed a fiber-optics probe that allows measurement of oxygenation in addition to perfusion in real time; this low profile probe can be utilized while sitting and during pressure reliefs. We have conducted a clinical trial at the National Rehabilitation Hospital on individual with spinal cord injury. The overriding goal of this project was to develop the evidence base for clinical recommendations on pressure reliefs. Results of the study will be presented.

  5. 46 CFR 56.50-25 - Safety and relief valve escape piping.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... discharging thereto and shall be led as near vertically as practicable to the atmosphere. (b) Expansion joints... valve discharges, when permitted to terminate in the machinery space, shall be led below the...

  6. 46 CFR 56.50-25 - Safety and relief valve escape piping.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... discharging thereto and shall be led as near vertically as practicable to the atmosphere. (b) Expansion joints... valve discharges, when permitted to terminate in the machinery space, shall be led below the...

  7. 46 CFR 56.50-25 - Safety and relief valve escape piping.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... discharging thereto and shall be led as near vertically as practicable to the atmosphere. (b) Expansion joints... valve discharges, when permitted to terminate in the machinery space, shall be led below the...

  8. 46 CFR 56.50-25 - Safety and relief valve escape piping.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... discharging thereto and shall be led as near vertically as practicable to the atmosphere. (b) Expansion joints... valve discharges, when permitted to terminate in the machinery space, shall be led below the...

  9. Significant issues and changes for ANSI/ASME OM-1 1981, part 1, ASME OMc code-1994, and ASME OM Code-1995, Appendix I, inservice testing of pressure relief devices in light water reactor power plants

    SciTech Connect

    Seniuk, P.J.

    1996-12-01

    This paper identifies significant changes to the ANSI/ASME OM-1 1981, Part 1, and ASME Omc Code-1994 and ASME OM Code-1995, Appendix I, {open_quotes}Inservice Testing of Pressure Relief Devices in Light-Water Reactor Power Plants{close_quotes}. The paper describes changes to different Code editions and presents insights into the direction of the code committee and selected topics to be considered by the ASME O&M Working Group on pressure relief devices. These topics include scope issues, thermal relief valve issues, as-found and as-left set-pressure determinations, exclusions from testing, and cold setpoint bench testing. The purpose of this paper is to describe some significant issues being addressed by the O&M Working Group on Pressure Relief Devices (OM-1). The writer is currently the chair of OM-1 and the statements expressed herein represents his personal opinion.

  10. 46 CFR 34.15-40 - Pressure relief-T/ALL.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Pressure relief-T/ALL. 34.15-40 Section 34.15-40... Extinguishing Systems, Details § 34.15-40 Pressure relief—T/ALL. (a) Where necessary, relatively tight... relieving excessive pressure accumulating within the compartment when the carbon dioxide is injected....

  11. 46 CFR 34.15-40 - Pressure relief-T/ALL.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Pressure relief-T/ALL. 34.15-40 Section 34.15-40... Extinguishing Systems, Details § 34.15-40 Pressure relief—T/ALL. (a) Where necessary, relatively tight... relieving excessive pressure accumulating within the compartment when the carbon dioxide is injected....

  12. 46 CFR 34.15-40 - Pressure relief-T/ALL.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Pressure relief-T/ALL. 34.15-40 Section 34.15-40... Extinguishing Systems, Details § 34.15-40 Pressure relief—T/ALL. (a) Where necessary, relatively tight... relieving excessive pressure accumulating within the compartment when the carbon dioxide is injected....

  13. 46 CFR 34.15-40 - Pressure relief-T/ALL.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Pressure relief-T/ALL. 34.15-40 Section 34.15-40... Extinguishing Systems, Details § 34.15-40 Pressure relief—T/ALL. (a) Where necessary, relatively tight... relieving excessive pressure accumulating within the compartment when the carbon dioxide is injected....

  14. 46 CFR 34.15-40 - Pressure relief-T/ALL.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Pressure relief-T/ALL. 34.15-40 Section 34.15-40... Extinguishing Systems, Details § 34.15-40 Pressure relief—T/ALL. (a) Where necessary, relatively tight... relieving excessive pressure accumulating within the compartment when the carbon dioxide is injected....

  15. Results of pressure locking and thermal binding tests of gate valves

    SciTech Connect

    DeWall, K.G.; Watkins, J.C.; McKellar, M.G.; Bramwell, D.

    1998-05-01

    The US Nuclear Regulatory Commission (NRC), Office of Nuclear Regulatory Research, is funding the Idaho National Engineering and Environmental Laboratory (INEEL) in performing research investigating the performance of gate valves subjected to pressure locking and thermal binding conditions. Pressure locking and thermal binding are phenomena that make a closed gate valve difficult to open. Pressure locking can occur when operating sequences or temperature changes cause the pressure of the fluid in the bonnet (and, in most gate valves, between the discs) to be higher than the pressure on the upstream and downstream sides of the disc assembly. Thermal binding can occur when thermal expansion/contraction effects cause the disc to be squeezed between the valve body seats. If the loads associated with pressure locking or thermal binding are very high, the actuator might not have the capacity to open the valve. The authors tested a flexible-wedge gate valve and a double-disc gate valve under pressure locking and thermal binding conditions. The results show that these valves are susceptible to pressure locking; however, they are not significantly affected by thermal binding. For the flexible-wedge gate valve, pressure locking loads (in terms of stem thrust) were higher than corresponding hydrostatic opening loads by a factor of 1.1 to 1.5. For the parallel disc gate valve, pressure locking loads were higher by a factor of 2.05 to 2.4. The results also show that seat leakage affects the bonnet pressurization rate when the valve is subjected to thermally induced pressure locking conditions.

  16. Methods for combining a theoretical and an empirical approach in modelling pressure and flow control valves for CAE-programs for fluid power circuits

    NASA Astrophysics Data System (ADS)

    Handroos, Heikki

    An analytical mathematical model for a fluid power valve uses equations based on physical laws. The parameters consist of physical coefficients, dimensions of the internal elements, spring constants, etc. which are not provided by the component manufacturers. The valve has to be dismantled in order to determine their values. The model is only in accordance with a particular type of valve construction and there are a large number of parameters. This is a major common problem in computer aided engineering (CAE) programs for fluid power circuits. Methods for solving this problem by combining a theoretical and an empirical approach are presented. Analytical models for single stage pressure and flow control valves are brought into forms which contain fewer parameters whose values can be determined from measured characteristic curves. The least squares criterion is employed to identify the parameter values describing the steady state of a valve. The steady state characteristic curves that are required data for this identification are quite often provided by the manufacturers. The parameters describing the dynamics of a valve are determined using a simple noncomputational method using dynamic characteristic curves that can be easily measured. The importance of the identification accuracy of the different parameters of the single stage pressure relief valve model is compared using a parameter sensitivity analysis method. A new comparison method called relative mean value criterion is used to compare the influences of variations of the different parameters to a nominal dynamic response.

  17. 40 CFR 63.169 - Standards: Pumps, valves, connectors, and agitators in heavy liquid service; instrumentation...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ..., and agitators in heavy liquid service; instrumentation systems; and pressure relief devices in liquid...: Pumps, valves, connectors, and agitators in heavy liquid service; instrumentation systems; and pressure relief devices in liquid service. (a) Pumps, valves, connectors, and agitators in heavy liquid...

  18. 40 CFR 63.169 - Standards: Pumps, valves, connectors, and agitators in heavy liquid service; instrumentation...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ..., and agitators in heavy liquid service; instrumentation systems; and pressure relief devices in liquid...: Pumps, valves, connectors, and agitators in heavy liquid service; instrumentation systems; and pressure relief devices in liquid service. (a) Pumps, valves, connectors, and agitators in heavy liquid...

  19. 40 CFR 63.169 - Standards: Pumps, valves, connectors, and agitators in heavy liquid service; instrumentation...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ..., and agitators in heavy liquid service; instrumentation systems; and pressure relief devices in liquid...: Pumps, valves, connectors, and agitators in heavy liquid service; instrumentation systems; and pressure relief devices in liquid service. (a) Pumps, valves, connectors, and agitators in heavy liquid...

  20. 40 CFR 63.169 - Standards: Pumps, valves, connectors, and agitators in heavy liquid service; instrumentation...

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ..., and agitators in heavy liquid service; instrumentation systems; and pressure relief devices in liquid...: Pumps, valves, connectors, and agitators in heavy liquid service; instrumentation systems; and pressure relief devices in liquid service. (a) Pumps, valves, connectors, and agitators in heavy liquid...

  1. 40 CFR 63.169 - Standards: Pumps, valves, connectors, and agitators in heavy liquid service; instrumentation...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ..., and agitators in heavy liquid service; instrumentation systems; and pressure relief devices in liquid...: Pumps, valves, connectors, and agitators in heavy liquid service; instrumentation systems; and pressure relief devices in liquid service. (a) Pumps, valves, connectors, and agitators in heavy liquid...

  2. A piezoelectric micro control valve with integrated capacitive sensing for ambulant blood pressure waveform monitoring

    NASA Astrophysics Data System (ADS)

    Groen, Maarten S.; Wu, Kai; Brookhuis, Robert A.; van Houwelingen, Marc J.; Brouwer, Dannis M.; Lötters, Joost C.; Wiegerink, Remco J.

    2014-12-01

    We have designed and characterized a MEMS microvalve with built-in capacitive displacement sensing and fitted it with a miniature piezoelectric actuator to achieve active valve control. The integrated displacement sensor enables high bandwidth proportional control of the gas flow through the valve. This is an essential requirement for non-invasive blood pressure waveform monitoring based on following the arterial pressure with a counter pressure. Using the capacitive sensor, we demonstrate negligible hysteresis in the valve control characteristics. Fabrication of the valve requires only two mask steps for deep reactive ion etching (DRIE) and one release etch.

  3. Non-reclosing pressure relief device for vacuum systems

    DOEpatents

    Swansiger, William A.

    1994-01-01

    A non-reclosing overpressure protection device such as a rupture disc provides a non-reclosing opening upon forcible contact with a knife blade. A bellows, having an inlet capable of being sealably connected to a source of pressure (the vacuum system) and an outlet containing the rupture disc, transmits the pressure in the system to the disc. The bellows maintains the disc away from the knife when the pressure is below an overpressure amount, and carries the disc to a position when the pressure is above an overpressure amount where the disc is ruptured by the knife.

  4. Non-reclosing pressure relief device for vacuum systems

    DOEpatents

    Swansiger, W.A.

    1994-02-08

    A non-reclosing overpressure protection device such as a rupture disc provides a non-reclosing opening upon forcible contact with a knife blade. A bellows, having an inlet capable of being sealably connected to a source of pressure (the vacuum system) and an outlet containing the rupture disc, transmits the pressure in the system to the disc. The bellows maintains the disc away from the knife when the pressure is below an overpressure amount, and carries the disc to a position when the pressure is above an overpressure amount where the disc is ruptured by the knife. 6 figures.

  5. A comparison of shoe insole materials in plantar pressure relief.

    PubMed

    Leber, C; Evanski, P M

    1986-12-01

    A clinical study was performed to evaluate the effectiveness of seven shoe insole materials and their ability to relieve areas of high plantar pressure. The following materials were tested: Latex foam, Plastazote, Dynafoam, Ortho felt, PPTR, Spenco, and Molo. Twenty-six patients with areas of high plantar pressure were tested using each of these materials. The Harris and Beath footprinting technique was used to measure plantar pressure. It was found that the average pressure of a clinically painful plantar area was 398.15kN/m2. All insole materials tested decreased this pressure, with averages ranging from 186.33kN/m2 to 286.35kN/m2. PPT, Plastazote and Spenco were the most effective products tested.

  6. Pressure model of a four-way spool valve for simulating electrohydraulic control systems

    NASA Technical Reports Server (NTRS)

    Gebben, V. D.

    1976-01-01

    An equation that relates the pressure flow characteristics of hydraulic spool valves was developed. The dependent variable is valve output pressure, and the independent variables are spool position and flow. This causal form of equation is preferred in applications that simulate the effects of hydraulic line dynamics. Results from this equation are compared with those from the conventional valve equation, whose dependent variable is flow. A computer program of the valve equations includes spool stops, leakage spool clearances, and dead-zone characteristics of overlap spools.

  7. 46 CFR 154.517 - Piping: Liquid pressure relief.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... STANDARDS FOR SELF-PROPELLED VESSELS CARRYING BULK LIQUEFIED GASES Design, Construction and Equipment Cargo... crossover headers, cargo hoses, and cargo loading arms must have means to relieve cargo pressure and...

  8. An air-pressure-free elastomeric valve for integrated nucleic acid analysis by capillary electrophoresis

    NASA Astrophysics Data System (ADS)

    Jung, Wooseok; Barrett, Matthew; Brooks, Carla; Rivera, Andrew; Birdsell, Dawn N.; Wagner, David M.; Zenhausern, Frederic

    2015-12-01

    We present a new elastomeric valve for integrated nucleic acid analysis by capillary electrophoresis. The valve functions include metering to capture a designated volume of biological sample into a polymerase chain reaction (PCR) chamber, sealing to preserve the sample during PCR cycling, and transfer of the PCR-products and on-chip formamide post-processing for the analysis of DNA fragments by capillary gel electrophoresis. This new valve differs from prior art polydimethylsiloxane (PDMS) valves in that the valve is not actuated externally by air-pressure or vacuum so that it simplifies a DNA analysis system by eliminating the need for an air-pressure or vacuum source, and off-cartridge solenoid valves, control circuit boards and software. Instead, the new valve is actuated by a thermal cycling peltier assembly integrated within the hardware instrument that tightly comes in contact with a microfluidic cartridge for thermal activation during PCR, so that it spontaneously closes the valve without an additional actuator system. The valve has bumps in the designated locations so that it has a self-alignment that does not require precise alignment of a valve actuator. Moreover, the thickness of the new valve is around 600 μm with an additional bump height of 400 μm so that it is easy to handle and very feasible to fabricate by injection molding compared to other PDMS valves whose thicknesses are around 30-100 μm. The new valve provided over 95% of metering performance in filling the fixed volume of the PCR chamber, preserved over 97% of the sample volume during PCR, and showed very comparable capillary electrophoresis peak heights to the benchtop assay tube controls with very consistent transfer volume of the PCR-product and on-chip formamide. The new valve can perform a core function for integrated nucleic acid analysis by capillary electrophoresis.

  9. Continuous-flow gas-lift installation design utilizing production-pressure-operated valve performance

    SciTech Connect

    Winkler, H.W.

    1995-12-31

    The variable-gradient design-line method is a widely accepted procedure for spacing gas-lift valves (GLVs) in a continuous-flow gas-lift (GL) installation. Injection-pressure-operated (IPO) and production-pressure-operated (PPO) GLVs can be used in a variable gradient designed installation. The primary purpose of GLVs is to unload a well to the desired depth of gas injection. If the installation design is based on a constant surface injection-gas pressure (p{sub io}), the GLVs must be opened by an increase in the flowing-production pressure at valve depth (p{sub pfD}) rather than an increase in injection-gas pressure at valve depth (p{sub ioD}). PPO, also called fluid-operated, valves are opened and closed by changes in p{sub pfD}. This paper outlines in detail the calculations for a variable-gradient continuous-flow installation design procedure based on a constant p{sub io} for spacing the unloading PPO valves. The valve spacing and port size selection includes performance characteristics of PPO GLVs. A simplified method for calculating the injection daily volumetric gas rate (q{sub gsc}) throughput of an unbalanced bellows type of PPO valve on the basis of a change in p{sub pfD} and the valve bellows-assembly load rate (B{sub lr}) is given in the Appendix.

  10. EVALUATION OF SPRING OPERATED RELIEF VALVE MAINTENANCE INTERVALS AND EXTENSION OF MAINTENANCE TIMES USING A WEIBULL ANALYSIS WITH MODIFIED BAYESIAN UPDATING

    SciTech Connect

    Harris, S.; Gross, R.; Mitchell, E.

    2011-01-18

    The Savannah River Site (SRS) spring operated pressure relief valve (SORV) maintenance intervals were evaluated using an approach provided by the American Petroleum Institute (API RP 581) for risk-based inspection technology (RBI). In addition, the impact of extending the inspection schedule was evaluated using Monte Carlo Simulation (MCS). The API RP 581 approach is characterized as a Weibull analysis with modified Bayesian updating provided by SRS SORV proof testing experience. Initial Weibull parameter estimates were updated as per SRS's historical proof test records contained in the Center for Chemical Process Safety (CCPS) Process Equipment Reliability Database (PERD). The API RP 581 methodology was used to estimate the SORV's probability of failing on demand (PFD), and the annual expected risk. The API RP 581 methodology indicates that the current SRS maintenance plan is conservative. Cost savings may be attained in certain mild service applications that present low PFD and overall risk. Current practices are reviewed and recommendations are made for extending inspection intervals. The paper gives an illustration of the inspection costs versus the associated risks by using API RP 581 Risk Based Inspection (RBI) Technology. A cost effective maintenance frequency balancing both financial risk and inspection cost is demonstrated.

  11. Performance of adjustable pressure-limiting (APL) valves in two different modern anaesthesia machines.

    PubMed

    Thomas, J; Weiss, M; Schmidt, A R; Buehler, P K

    2017-01-01

    The ability to gently ventilate a patient's lungs using a self-inflating bag requires a properly working adjustable pressure-limiting (APL) valve. We compared the performance of the APL valves of the GE Aisys CS(2) and the Draeger Fabius anaesthetic machines during closure and opening from 1-20 and from 20-1 cmH2 O, using standardised experimental baby and adolescent patient lung models. Airway pressures and inspiratory tidal volumes were measured using an ASL-5000 test lung and a GE Aisys CS(2) near-patient spirometry sensors. In both lung models, the GE Aisys CS(2) APL valves demonstrated non-linear behaviours for airway pressures and for inspiratory tidal volumes, with a sharp increase at set APL pressure levels of 8-10 cmH2 O. With further closure of the GE Aisys CS(2) APL valves up to 20 cmH2 O, inspiratory tidal volumes decreased to ~50% of the highest values measured. Airway pressures in the Draeger Fabius APL valves demonstrated a near linear increase and decrease. Airway pressure values measured in the Draeger Fabius were never higher than those set by the APL valves, whereas in the GE Aisys CS(2) , they considerably exceeded set pressures (by up to 27 cmH2 O). We conclude that the performance of the GE Aisys CS(2) APL valve does not allow safe bag-assisted ventilation of a patient's lungs.

  12. 49 CFR 192.199 - Requirements for design of pressure relief and limiting devices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... ports designed to prevent accumulation of water, ice, or snow, located where gas can be discharged into... seats that are designed not to stick in a position that will make the device inoperative; (c) Be... source of pressure, be designed to prevent unauthorized operation of any stop valve that will make...

  13. 49 CFR 192.199 - Requirements for design of pressure relief and limiting devices.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... seats that are designed not to stick in a position that will make the device inoperative; (c) Be designed and installed so that it can be readily operated to determine if the valve is free, can be tested to determine the pressure at which it will operate, and can be tested for leakage when in the...

  14. 49 CFR 178.348-4 - Pressure relief.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...—calories per gram (BTU/lb); Z = The compressibility factor for the vapor (if this factor is unknown, let Z... heat at constant pressure, in -calories per gram degree centigrade (BTU/lb °F.); and Cv = The specific heat at constant volume, in -calories per gram degree centigrade (BTU/lb °F.)....

  15. 49 CFR 178.348-4 - Pressure relief.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ...—calories per gram (BTU/lb); Z = The compressibility factor for the vapor (if this factor is unknown, let Z... heat at constant pressure, in -calories per gram degree centigrade (BTU/lb °F.); and Cv = The specific heat at constant volume, in -calories per gram degree centigrade (BTU/lb °F.)....

  16. 49 CFR 178.348-4 - Pressure relief.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ...—calories per gram (BTU/lb); Z = The compressibility factor for the vapor (if this factor is unknown, let Z... heat at constant pressure, in -calories per gram degree centigrade (BTU/lb °F.); and Cv = The specific heat at constant volume, in -calories per gram degree centigrade (BTU/lb °F.)....

  17. 49 CFR 178.348-4 - Pressure relief.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...—calories per gram (BTU/lb); Z = The compressibility factor for the vapor (if this factor is unknown, let Z... heat at constant pressure, in -calories per gram degree centigrade (BTU/lb °F.); and Cv = The specific heat at constant volume, in -calories per gram degree centigrade (BTU/lb °F.)....

  18. 49 CFR 178.348-4 - Pressure relief.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... = The latent heat of vaporization of the lading—calories per gram (BTU/lb); Z = The compressibility... pressure, in -calories per gram degree centigrade (BTU/lb °F.); and Cv = The specific heat at constant volume, in -calories per gram degree centigrade (BTU/lb °F.). [Amdt. 178-89, 54 FR 25032, June 12,...

  19. Experiment and numerical simulation of cavitation performance on a pressure-regulating valve with different openings

    NASA Astrophysics Data System (ADS)

    Qu, W. S.; Tan, L.; Cao, S. L.; Xu, Y.; Huang, J.; Xu, Q. H.

    2015-01-01

    As a kind of widely used device in pipe system for pressure and flow rate regulating, the valve would experience cavitation in the case when a sharp pressure drop occurs, which will induce the energy loss, noise and vibration of pipeline system, and even operational accidents. The experiment on flow resistance coefficient of a DN600 pressure-regulating valve under operation conditions from 0% to 100% openings is conducted. Based on the RNG k-e turbulence model and the Rayleigh-Plesset cavitation equation, a set of computational model is developed to simulate the turbulent flow in the valve under operational conditions from 0% to 100% openings. The computational results of flow resistance coefficient are compared to the experimental data. And the numerical simulation is employed to predict the cavitation performance of the valve at different inlet flow conditions. The transient cavitating flow is calculated to reveal the time evolution of cavitation in the valve.

  20. Functional Changes of Diaphragm Type Shunt Valves Induced by Pressure Pulsation

    NASA Astrophysics Data System (ADS)

    Lee, Chong-Sun; Suh, Chang-Min; Ra, Young-Shin

    Shunt valves used to treat patients with hydrocephalus were tested to investigate influence of pressure pulsation on their flow control characteristics. Our focus was on flow dynamic and functional changes of the small and thin diaphragms in the valves that serve as the main flow control mechanism and are made from silicone elastomer. Firstly, pressure-flow control curves were compared under pulsed and steady flow (without pulsation) conditions. Secondly, functional changes of the valves were tested after a long-term continuous pulsation with a peristaltic pump. Thirdly, flushing procedures selectively conducted by neurosurgeons were simulated with a fingertip pressed on the dome of the valves. As 20cc/hr of flow rate was adjusted at a constant pressure, application of 40mmH2O of pressure pulse increased flow rate through shunt valves more than 60%. As a 90cm length silicone catheter was connected to the valve outlet, increase in the flow rate was substantially reduced to 17.5%. Pressure-flow control characteristics of some valves showed significant changes after twenty-eight days of pressure pulsation at 1.0 Hz under 50.0cc/hr of flow rate. Flushing simulation resulted in temporary decrease in the pressure level. It took three hours to fully recover the normal pressure-flow control characteristics after the flushing. Our results suggest that shunt valves with a thin elastic diaphragm as the main flow control mechanism are sensitive to intracranial pressure pulsation or pressure spikes enough to change their pressure-flow control characteristics.

  1. 30 CFR 18.28 - Devices for pressure relief, ventilation, or drainage.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... TESTING, EVALUATION, AND APPROVAL OF MINING PRODUCTS ELECTRIC MOTOR-DRIVEN MINE EQUIPMENT AND ACCESSORIES Construction and Design Requirements § 18.28 Devices for pressure relief, ventilation, or drainage. (a) Devices... designed that they can be cleaned readily. Provision shall be made for secure attachment of such...

  2. 49 CFR 179.103-4 - Safety relief devices and pressure regulators.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 49 Transportation 3 2014-10-01 2014-10-01 false Safety relief devices and pressure regulators. 179.103-4 Section 179.103-4 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION...

  3. 49 CFR 179.103-4 - Safety relief devices and pressure regulators.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Safety relief devices and pressure regulators. 179.103-4 Section 179.103-4 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION...

  4. 49 CFR 179.103-4 - Safety relief devices and pressure regulators.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Safety relief devices and pressure regulators. 179.103-4 Section 179.103-4 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION...

  5. High-temperature, high-pressure oxygen metering valve

    NASA Technical Reports Server (NTRS)

    Christianson, Rollin C. (Inventor); Lycou, Peter P. (Inventor); Daniel, James A. (Inventor)

    1993-01-01

    A control valve includes a body defining a central cavity arranged between a fluid inlet and outwardly-diverging first and second fluid outlets respectively disposed in a common transverse plane. A valve member is arranged in the cavity for rotation between first and second operating positions where a transverse fluid passage through the valve member alternatively communicates the fluid inlet with one or the other of the fluid outlets. To minimize fluid turbulence when the valve member is rotated to an alternate operating position, the fluid passage has a convergent entrance for maintaining the passage in permanent communication with the fluid inlet as well as an oblong exit opening with spaced side walls for enabling the exit opening to temporarily span the first and second fluid outlets as the valve member is turned between its respective operating positions.

  6. Gas flow across a wet screen - Analogy to a relief valve with hysteresis

    NASA Technical Reports Server (NTRS)

    Nachman, A.; Dodge, F. T.

    1983-01-01

    The flow of gas through a wet fine-mesh screen is analyzed in terms of the capillary forces of the liquid wetting the screen and the pressure difference across the screen thickness driving the gas flow. Several different types of time-dependent flow are shown to be possible. The most interesting type is one in which the pressure difference opens small channels in the liquid, which are then closed rapidly by the wetting action of the liquid. The opening and closing exhibit hysteresis, and the flow is highly oscillatory.

  7. Rankine cycle condenser pressure control using an energy conversion device bypass valve

    DOEpatents

    Ernst, Timothy C; Nelson, Christopher R; Zigan, James A

    2014-04-01

    The disclosure provides a waste heat recovery system and method in which pressure in a Rankine cycle (RC) system of the WHR system is regulated by diverting working fluid from entering an inlet of an energy conversion device of the RC system. In the system, an inlet of a controllable bypass valve is fluidly coupled to a working fluid path upstream of an energy conversion device of the RC system, and an outlet of the bypass valve is fluidly coupled to the working fluid path upstream of the condenser of the RC system such that working fluid passing through the bypass valve bypasses the energy conversion device and increases the pressure in a condenser. A controller determines the temperature and pressure of the working fluid and controls the bypass valve to regulate pressure in the condenser.

  8. 46 CFR 53.05-1 - Safety valve requirements for steam boilers (modifies HG-400 and HG-401).

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 2 2013-10-01 2013-10-01 false Safety valve requirements for steam boilers (modifies HG... (CONTINUED) MARINE ENGINEERING HEATING BOILERS Pressure Relieving Devices (Article 4) § 53.05-1 Safety valve requirements for steam boilers (modifies HG-400 and HG-401). (a) The pressure relief valve requirements and...

  9. 46 CFR 53.05-1 - Safety valve requirements for steam boilers (modifies HG-400 and HG-401).

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 2 2014-10-01 2014-10-01 false Safety valve requirements for steam boilers (modifies HG... (CONTINUED) MARINE ENGINEERING HEATING BOILERS Pressure Relieving Devices (Article 4) § 53.05-1 Safety valve requirements for steam boilers (modifies HG-400 and HG-401). (a) The pressure relief valve requirements and...

  10. 46 CFR 53.05-1 - Safety valve requirements for steam boilers (modifies HG-400 and HG-401).

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 2 2011-10-01 2011-10-01 false Safety valve requirements for steam boilers (modifies HG... (CONTINUED) MARINE ENGINEERING HEATING BOILERS Pressure Relieving Devices (Article 4) § 53.05-1 Safety valve requirements for steam boilers (modifies HG-400 and HG-401). (a) The pressure relief valve requirements and...

  11. 46 CFR 53.05-1 - Safety valve requirements for steam boilers (modifies HG-400 and HG-401).

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 2 2012-10-01 2012-10-01 false Safety valve requirements for steam boilers (modifies HG... (CONTINUED) MARINE ENGINEERING HEATING BOILERS Pressure Relieving Devices (Article 4) § 53.05-1 Safety valve requirements for steam boilers (modifies HG-400 and HG-401). (a) The pressure relief valve requirements and...

  12. 46 CFR 53.05-1 - Safety valve requirements for steam boilers (modifies HG-400 and HG-401).

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 2 2010-10-01 2010-10-01 false Safety valve requirements for steam boilers (modifies HG... (CONTINUED) MARINE ENGINEERING HEATING BOILERS Pressure Relieving Devices (Article 4) § 53.05-1 Safety valve requirements for steam boilers (modifies HG-400 and HG-401). (a) The pressure relief valve requirements and...

  13. Failure Analysis of High Pressure Test Facility Control Valves

    DTIC Science & Technology

    2013-10-01

    larger than the axial load applied to the stem by the actuator in the closed valve position), so we decided that no further buckling analysis was...caused the stem to bend. There are only two modes by which the stem could have bent in the manner it did: buckling and/or a cantilever load...load; however, we have clearly demonstrated on other valves (much to our embarrassment) that it is entirely possible to buckle the stem by over

  14. 14 CFR 25.365 - Pressurized compartment loads.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... differential loads from zero up to the maximum relief valve setting. (b) The external pressure distribution in flight, and stress concentrations and fatigue effects must be accounted for. (c) If landings may be made... to withstand the pressure differential loads corresponding to the maximum relief valve...

  15. 14 CFR 23.365 - Pressurized cabin loads.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... zero up to the maximum relief valve setting. (b) The external pressure distribution in flight, and any stress concentrations, must be accounted for. (c) If landings may be made with the cabin pressurized... corresponding to the maximum relief valve setting multiplied by a factor of 1.33, omitting other loads. (e) If...

  16. 14 CFR 25.365 - Pressurized compartment loads.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... differential loads from zero up to the maximum relief valve setting. (b) The external pressure distribution in flight, and stress concentrations and fatigue effects must be accounted for. (c) If landings may be made... to withstand the pressure differential loads corresponding to the maximum relief valve...

  17. 14 CFR 25.365 - Pressurized compartment loads.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... differential loads from zero up to the maximum relief valve setting. (b) The external pressure distribution in flight, and stress concentrations and fatigue effects must be accounted for. (c) If landings may be made... to withstand the pressure differential loads corresponding to the maximum relief valve...

  18. 14 CFR 23.365 - Pressurized cabin loads.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... zero up to the maximum relief valve setting. (b) The external pressure distribution in flight, and any stress concentrations, must be accounted for. (c) If landings may be made with the cabin pressurized... corresponding to the maximum relief valve setting multiplied by a factor of 1.33, omitting other loads. (e) If...

  19. 14 CFR 23.365 - Pressurized cabin loads.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... zero up to the maximum relief valve setting. (b) The external pressure distribution in flight, and any stress concentrations, must be accounted for. (c) If landings may be made with the cabin pressurized... corresponding to the maximum relief valve setting multiplied by a factor of 1.33, omitting other loads. (e) If...

  20. 14 CFR 25.365 - Pressurized compartment loads.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... differential loads from zero up to the maximum relief valve setting. (b) The external pressure distribution in flight, and stress concentrations and fatigue effects must be accounted for. (c) If landings may be made... to withstand the pressure differential loads corresponding to the maximum relief valve...

  1. Numerical investigation of cavitation flow inside spool valve with large pressure drop

    NASA Astrophysics Data System (ADS)

    Deng, Jian; Pan, Dingyi; Xie, Fangfang; Shao, Xueming

    2015-12-01

    Spool valves play an important role in fluid power system. Cavitation phenomena happen frequently inside the spool valves, which cause structure damages, noise and lower down hydrodynamic performance. A numerical tools incorporating the cavitation model, are developed to predict the flow structure and cavitation pattern in the spool valve. Two major flow states in the spool valve chamber, i.e. flow-in and flow-out, are studies. The pressure distributions along the spool wall are first investigated, and the results agree well with the experimental data. For the flow-in cases, the local pressure at the throttling area drops much deeper than the pressure in flow-out cases. Meanwhile, the bubbles are more stable in flow-in cases than those in flow-out cases, which are ruptured and shed into the downstream.

  2. A method for evaluating pressure locking and thermal binding of gate valves

    SciTech Connect

    Dogan, T.

    1996-12-01

    A method is described to evaluate the susceptibility of gate valves to pressure locking and thermal binding. Binding of the valve disc in the closed position due to high pressure water trapped in the bonnet cavity (pressure locking) or differential thermal expansion of the disk in the seat (thermal binding) represents a potential mechanism that can prevent safety-related systems from functioning when called upon. The method described here provides a general equation that can be applied to a given gate valve design and set of operating conditions to determine the susceptibility of the valve to fail due to disc binding. The paper is organized into three parts. The first part discusses the physical mechanisms that cause disc binding. The second part describes the mathematical equations. The third part discusses the conclusions.

  3. VALVE

    DOEpatents

    Arkelyan, A.M.; Rickard, C.L.

    1962-04-17

    A gate valve for controlling the flow of fluid in separate concentric ducts or channels by means of a single valve is described. In one position, the valve sealing discs engage opposed sets of concentric ducts leading to the concentric pipes defining the flow channels to block flow therethrough. In another position, the discs are withdrawn from engagement with the opposed ducts and at the same time a bridging section is interposed therebetween to define concentric paths coextensive with and connecting the opposed ducts to facilitate flow therebetween. A wedge block arrangement is employed with each sealing disc to enable it to engage the ducts. The wedge block arrangement also facilitates unobstructcd withdrawal of the discs out of the intervening space between the sets of ducts. (AEC)

  4. Valve

    DOEpatents

    Cho, Nakwon

    1980-01-01

    A positive acting valve suitable for operation in a corrosive environment is provided. The valve includes a hollow valve body defining an open-ended bore for receiving two, axially aligned, spaced-apart, cylindrical inserts. One insert, designated the seat insert, terminates inside the valve body in an annular face which lies within plane normal to the axis of the two inserts. An elastomeric O-ring seal is disposed in a groove extending about the annular face. The other insert, designated the wedge insert, terminates inside the valve body in at least two surfaces oppositely inclined with respect to each other and with respect to a plane normal to the axis of the two inserts. An elongated reciprocable gate, movable between the two inserts along a path normal to the axis of the two inserts, has a first flat face portion disposed adjacent and parallel to the annular face of the seat insert. The gate has a second face portion opposite to the first face portion provided with at least two oppositely inclined surfaces for mating with respective inclined surfaces of the wedge insert. An opening is provided through the gate which registers with a flow passage through the two inserts when the valve is open. Interaction of the respective inclined surfaces of the gate and wedge insert act to force the first flat face portion of the gate against the O-ring seal in the seat insert at the limits of gate displacement where it reaches its respective fully open and fully closed positions.

  5. NASA Helps Industry Relieve Pressure Safely

    NASA Technical Reports Server (NTRS)

    2003-01-01

    In many industrial applications, pressure relief valves (PRV) perform the critical function of safely releasing pressure before potentially damaging build-ups occur. Conventional relief valves, however, have proven unstable, leading to premature wear and devasting consequences. A high-performance pressure relief valve, the PRV95, now being manufactured my Marotta Scientific Controls, Inc., of Montville, NJ, provides the answer to premature wear and instability. Using an improved valve design developed under a NASA Small Business Innovation Research Program (SBIR) contract from John C. Stennis Space Center (SSC), Marotta's PRV95 pressure relief valve provides stability over the entire operational range, from fully closed to fully open. The valve employs upstream control for valve positioning, that makes the valve more stable and affords excellent repeatability with minimal lag time. 'It opens and closes softly, and does not oscillate or generate hard impacts; oscillation can result in a hard impact pressure release, which can lead to an explosion in the presence of oxygen,' says Bill St. Cyr, Chief of Test Technology Branch at Stennis Space Center. Marotta's PRV95 design is also unique in its ability to maintain a seal near the set point of the relief limit. Typically, relief valves seal tightly up to 90% of set point and then reseat when pressure is reduced to 85% of set point. The PRV95 technology maintains seal integrity until 98% of set point and will reseat a 95-97% of set point. This allows the operator to protect his system while not exceeding its limits.

  6. Radial-directed fluid-pressure-loaded all-metal-sealed gate valve

    DOEpatents

    Batzer, Thomas H.

    1992-01-01

    A large diameter gate valve uses a radially directed fluid pressure loaded all metal seal formed by engaging and disengaging a fixed and a moveable seal element. The fixed element is formed of a circular flange which contains a pressure chamber with a deformable wall, and is mounted to the valve body. The moving seal element contains an annular recess which mates with the circular flange, and is carried on a moveable sub-frame which moves on a frame fixed in the valve body. The valve opening defines an axis in a first direction, and the sub-frame moves through the valve body in a second direction which is substantially perpendicular to the first direction. The sub-frame and moveable seal element move in the second direction until the moveable element reaches a stop mounted in the valve body at which position the moveable element is aligned with but spaced apart from the fixed element. As the sub-frame continues to move in the second direction, the moveable element is forced to move toward and engage the fixed element. The pressure chamber in the flange is then pressurized to complete the seal.

  7. Skin microvascular and metabolic response to pressure relief maneuvers in people with spinal cord injury

    NASA Astrophysics Data System (ADS)

    Ramella-Roman, Jessica C.; Le, Du V. N.; Ghassemi, Pejhman; Nguyen, Thu A.; Lichy, Alison; Groah, Suzanne

    2013-02-01

    Clinician's recommendations on wheelchair pressure reliefs in the context of the high prevalence of pressure ulcers that occur in people with spinal cord injury is not supported by strong experimental evidence. Some data indicates that altered tissue perfusion and oxygenation occurring under pressure loads, such as during sitting, induce various pathophysiologic changes that may lead to pressure ulcers. Pressure causes a cascade of responses, including initial tissue hypoxia, which leads to ischemia, vascular leakage, tissue acidification, compensatory angiogenesis, thrombosis, and hyperemia, all of which may lead to tissue damage. We have developed an advanced skin sensor that allows measurement of oxygenation in addition to perfusion, and can be safely used during sitting. The sensor consists of a set of fiber optics probes, spectroscopic and Laser Doppler techniques that are used to obtain parameters of interest. The overriding goal of this project is to develop the evidence base for clinical recommendations on pressure reliefs. In this paper we will illustrate the experimental apparatus as well as some preliminary results of a small clinical trial conducted at the National Rehabilitation Hospital.

  8. Innovative, High-Pressure, Cryogenic Control Valve: Short Face-to-Face, Reduced Cost

    NASA Technical Reports Server (NTRS)

    Wilkes, Karlin; Larsen, Ed; McCourt, Jackson

    2004-01-01

    A control valve that can throttle high pressure cryogenic fluid embodies several design features that distinguish it over conventional valves designed for similar applications. Field and design engineers worked together to create a valve that would simplify installation, trim changes, and maintenance, thus reducing overall cost. The seals and plug stem packing were designed to perform optimally in cryogenic temperature ranges. Unlike conventional high-pressure cryogenic valves, the trim size can be changed independent of the body. The design feature that provides flexibility for changing the trim is a split body. The body is divided into an upper and a lower section with the seat ring sandwiched in between. In order to maintain the plug stem packing at an acceptable sealing temperature during cryogenic service, heat-exchanging fins were added to the upper body section (see figure). The body is made of stainless steel.

  9. Aortic Valve Regurgitation

    MedlinePlus

    ... valve. Also, a narrowing of the aortic valve (aortic stenosis) can be associated with leaking. High blood pressure (hypertension). High blood pressure may stretch the root of the aorta where the aortic valve sits. The valve flaps ( ...

  10. Numerical Simulation of Flow-Induced Noise in High Pressure Reducing Valve

    PubMed Central

    Wei, Lin; Zhu, Guorong; Qian, Jinyuan; Fei, Yang; Jin, Zhijiang

    2015-01-01

    The main objective of this paper is to study the characteristics of flow-induced noise in high pressure reducing valve (HPRV) and to provide some guidance for noise control. Based on computational fluid dynamics (CFD), numerical method was used to compute flow field. Ffowcs Williams and Hawkings Model was applied to obtain acoustic signals. The unsteady flow field shows that noise sources are located at the bottom of plug for valve without perforated plate, and noise sources are behind the plate for valve with perforated plate. Noise directivity analysis and spectrum characteristics indicate that the perforated plate could help to reduce noise effectively. Inlet pressure has great effects on sound pressure level (SPL). The higher inlet pressure will lead to larger SPL at high frequency. When the maximum Ma is close to 1, SPL at low frequency becomes very high. PMID:26061396

  11. Transient hydrodynamics of in-line valves in viscoelastic pressurized pipes: long-period analysis

    NASA Astrophysics Data System (ADS)

    Meniconi, Silvia; Brunone, Bruno; Ferrante, Marco; Massari, Christian

    2012-07-01

    The literature contains few reports devoted to the analysis of the effects of a partially closed in-line valve on the characteristics of transients in viscoelastic pressurized pipes. In this paper a contribution to the analysis of the long-period behavior of pressure is offered from both the experimental and numerical modeling point of view. In the first part, laboratory tests and the related results—noticeably extensive with respect to the existing literature—are examined. More precisely, the dependance of the damping of the dimensionless pressure maximum values on the initial conditions and in-line valve local head loss coefficient is shown. In the second part, a 1-D numerical model is developed by determining its parameters within a physically based procedure. Model parameters are obtained by considering transients in a constant-diameter pipe (single pipe) and then exported to the case of pipes with a partially closed in-line valve (in-line valve pipe). Moreover, particular attention is devoted to the modalities of specifying boundary conditions. In particular, the quasi-steady-state approach is followed for determining the transient local head loss due to the partially closed in-line valve and the actual supply conditions and characteristics of the maneuver are taken into account. Finally, the effect of unsteady friction and viscoelasticity is examined in both single and in-line valve pipes.

  12. Numerical acoustic characteristics and optimum design of the pressure reducing valve

    NASA Astrophysics Data System (ADS)

    Guo, P. C.; Sun, L. G.; Sun, S. H.; Feng, J. J.; Wu, K. G.; Luo, X. Q.

    2016-11-01

    The pressure reducing valves are widely used in the technological water supplied ways of gravity flow. A credible pressure reducing valve can provide stable cooling water for units with extremely low maintenance cost and labor intensity in a fairly long period of time. In this paper, a three-dimensional numerical simulation of flow field and acoustic characteristics towards a combined type pressure reducing valve was carried out based on ANSYS Fluent and the FW-H equation. The numerical results achieve the regulation of noise generation, transmission and attenuation. It shows that the sound pressure level of monitoring points seem to be higher and large gradient at low frequencies under the same flow velocity, while it presents reverse results with the increment of frequency and maintains a constant valve finally. At the same time, the monitoring points in the vicinity of throttling cone shows higher sound pressure level and upstream noise is lower than downstream's. Aiming at the problem of valve noise, a modified measure to reduce the flow-induced noise was proposed.

  13. Valve assembly for use with high temperature and high pressure fluids

    DOEpatents

    De Feo, Angelo

    1982-01-01

    The valve assembly for use with high temperature and high pressure fluids has inner and outer spaced shells and a valve actuator support of inner and outer spaced members which are connected at their end portions to the inner and outer shells, respectively, to extend substantially normal to the longitudinal axis of the inner shell. A layer of resilient heat insulating material covers the outer surfaces of the inner shell and the inner actuator support member and is of a thickness to only occupy part of the spaces between the inner and outer shells and inner and outer actuator support members. The remaining portion of the space between the inner and outer shells and the space between the inner and outer members is substantially filled with a body of castable, rigid refractory material. A movable valve member is disposed in the inner shell. A valve actuator assembly is supported in the valve actuator support to extend into the inner shell for connection with the movable valve member for movement of the movable valve member to positions from a fully open to a fully closed position to control flow of fluid through the inner shell. An anchor mneans is disposed adjacent opposite sides of the axis of the valve actuator support and attached to the inner shell so that relative radial movement between the inner and outer shell is permitted by the layer of resilient heat insulating material and relative longitudinal movement of the inner shell to the outer shell is permitted in opposite directions from the anchor means to thereby maintain the functional integrity of the movable valve member by providing an area of the inner shell surrounding the movable valve member longitdinally stationary, but at the same time allowing radial movement.

  14. A Respiratory Airway-Inspired Low-Pressure, Self-Regulating Valve for Drip Irrigation

    NASA Astrophysics Data System (ADS)

    Wang, Ruo-Qian; Winter, Amos G.; GEAR Lab Team

    2015-11-01

    One of the most significant barriers to achieving large-scale dissemination of drip irrigation is the cost of the pump and power system. An effective means of reducing power consumption is by reducing pumping pressure. The principle source of pressure drop in a drip system is the high flow resistance in the self-regulating flow resistors installed at the outlets of the pips, which evenly distribute water over a field. Traditional architectures require a minimum pressure of ~1 bar to maintain a constant flow rate; our aim is to reduce this pressure by 90% and correspondingly lower pumping power to facilitate the creation of low-cost, off-grid drip irrigation systems. This study presents a new Starling resistor architecture that enables the adjustment of flow rate with a fixed minimum pressure demand of ~0.1 bar. A Starling resistor is a flexible tube subjected to a transmural pressure, which collapses the tube to restrict flow. Our design uses a single pressure source to drive flow through the flexible tube and apply a transmural pressure. Flow into the flexible tube is restricted with a needle valve, to increase the transmural pressure. Using this device, a series of experiments were conducted with different flexible tube diameters, lengths and wall thickness. We found that the resistance of the needle valve changes flow rate but not the minimum transmural pressure required to collapse the tube. A lumped-parameter model was developed to capture the relationships between valve openings, pressure, and flow rates.

  15. Numerical simulation analysis and optimum design for combined type pressure reducing valves

    NASA Astrophysics Data System (ADS)

    Gou, D. M.; Guo, P. C.; Zheng, X. B.; Luo, X. Q.; Sun, L. G.

    2016-05-01

    Pressure reducing valve is an extremely significant equipment of energy dissipation for the water supply by gravity with pressure reducing technology in hydropower stations, and which has a pronounced effect on the normal technical water supply even safety operation for the hydropower units. A three-dimensional numerical calculation of flow field and cavitation characteristics towards a combined type pressure reducing valves was carried out based on the system of technical water supply in this paper. The numerical results show that the investigated valve could meet the requirements of technological supply water pressure and great pressure loss was caused when the water flow was accelerated by narrow overflowing section between throttling cone and valve seat. At working operation, obvious cavitation phenomenon was observed on the surface of throttling cone, and the maximum volume fraction of vapor reached 0.537%. Based on above researches, this paper introduces an optimization model for profile line design of throttling cone. The optimal results show that the cavitation performance is effectively improved with identical pressure drop compared with original results.

  16. Critical shunt-induced subdural hematoma treated with combined pressure-programmable valve implantation and endoscopic third ventriculostomy.

    PubMed

    Fukuhara, T; Vorster, S J; Luciano, M G

    2000-07-01

    The authors present 2 patients with VP shunt-induced subdural hematomas (SDH) treated with pressure-programmable valve implantation and endoscopic third ventriculostomies (TV). The first patient is an 11-year-old girl who developed a shunt-induced SDH. Revision of the shunt valve with a higher-pressure valve resulted in a prolonged deterioration of her consciousness. External ventricular drainage at low pressure led to clinical improvement. A pressure-programmable valve set at 50 mm H(2)O was implanted, and the pressure gradually increased. At a pressure of 120 mm H(2)O symptoms recurred, even though the subdural collection was beginning to decrease in size. An endoscopic TV was performed, and the valve pressure was then increased to 200 mm H(2)O without any neurological symptoms. The second patient, a 7-year-old boy with shunt-induced SDH, had recurrent SDH, even after shunt revision with placement of a higher-pressure valve, which resulted in prolonged lethargy. A pressure-programmable valve was implanted with concurrent endoscopic TV. Gradual valve pressure increases up to 200 mm H(2)O could be performed without recurrent symptoms. Eventually, the shunt system was ligated to resolve residual positional headache, and the TV has been patent for more than 3 years. In both patients, the pressure-programmable valve was useful, since the optimal CSF drainage pressure changed during the period of recovery from symptomatic subdural collections. Concurrent TV appeared to enable increasing the valve pressure gradually without any neurological symptoms. The advantages of this combined approach are discussed.

  17. Hypertension and hydronephrosis: rapid resolution of high blood pressure following relief of bilateral ureteric obstruction.

    PubMed

    Chalisey, Anil; Karim, Mahzuz

    2013-03-01

    Hypertension secondary to hydronephrosis is not commonly reported in the medical literature. Tubuloglomerular feedback and the renin-angiotensin-aldosterone axis are thought to mediate this process. We describe a patient presenting with acute kidney injury and bilateral hydronephrosis secondary to pelvic malignancy in which peripheral venous renin and aldosterone were elevated. Her blood pressure improved rapidly following insertion of bilateral nephrostomies. The speed of resolution of hypertension following relief of obstruction suggests that humorally mediated vasoconstriction can play an important role in the mechanism by which hydronephrosis causes hypertension. We also discuss other causes of renal parenchymal compression that may lead to the development of hypertension.

  18. Coincident steam generator tube rupture and stuck-open safety relief valve carryover tests: MB-2 steam generator transient response test program

    SciTech Connect

    Garbett, K; Mendler, O J; Gardner, G C; Garnsey, R; Young, M Y

    1987-03-01

    In PWR steam generator tube rupture (SGTR) faults, a direct pathway for the release of radioactive fission products can exist if there is a coincident stuck-open safety relief valve (SORV) or if the safety relief valve is cycled. In addition to the release of fission products from the bulk steam generator water by moisture carryover, there exists the possibility that some primary coolant may be released without having first mixed with the bulk water - a process called primary coolant bypassing. The MB-2 Phase II test program was designed specifically to identify the processes for droplet carryover during SGTR faults and to provide data of sufficient accuracy for use in developing physical models and computer codes to describe activity release. The test program consisted of sixteen separate tests designed to cover a range of steady-state and transient fault conditions. These included a full SGTR/SORV transient simulation, two SGTR overfill tests, ten steady-state SGTR tests at water levels ranging from very low levels in the bundle up to those when the dryer was flooded, and three moisture carryover tests without SGTR. In these tests the influence of break location and the effect of bypassing the dryer were also studied. In a final test the behavior with respect to aerosol particles in a dry steam generator, appropriate to a severe accident fault, was investigated.

  19. Spinal Cord Injury and Pressure Ulcer Prevention: Using Functional Activity in Pressure Relief

    PubMed Central

    Stinson, May; Gillan, Cathy; Morton, Julie; Gardner, Evie; Sprigle, Stephen

    2013-01-01

    Background. People with spinal cord injury (SCI) are at increased risk of pressure ulcers due to prolonged periods of sitting. Concordance with pressure relieving movements is poor amongst this population, and one potential alternative to improve this would be to integrate pressure relieving movements into everyday functional activities. Objectives. To investigate both the current pressure relieving behaviours of SCI individuals during computer use and the application of an ergonomically adapted computer-based activity to reduce interface pressure. Design. Observational and repeated measures design. Setting. Regional Spinal Cord Injury Unit. Participants. Fourteen subjects diagnosed with SCI (12 male, 2 female). Intervention.Comparing normal sitting to seated movements and induced forward reaching positions. Main Outcome Measures. Interface pressure measurements: dispersion index (DI), peak pressure index (PPI), and total contact area (CA). The angle of trunk tilt was also measured. Results. The majority of movements yielded less than 25% reduction in interface pressure compared to normal sitting. Reaching forward by 150% of arm length during an adapted computer activity significantly reduced DI (P < 0.05), angle of trunk tilt (p<0.05), and PPI for both ischial tuberosity regions (P < 0.001) compared to normal sitting. Conclusion. Reaching forward significantly redistributed pressure at the seating interface, as evidenced by the change in interface pressures compared to upright sitting. PMID:23691301

  20. Pressure disequilibria induced by rapid valve closure in noble gas extraction lines

    USGS Publications Warehouse

    Morgan, Leah; Davidheiser-Kroll, Brett

    2015-01-01

    Pressure disequilibria during rapid valve closures can affect calculated molar quantities for a range of gas abundance measurements (e.g., K-Ar geochronology, (U-Th)/He geochronology, noble gas cosmogenic chronology). Modeling indicates this effect in a system with a 10 L reservoir reaches a bias of 1% before 1000 pipette aliquants have been removed from the system, and a bias of 10% before 10,000 aliquants. Herein we explore the causes and effects of this problem, which is the result of volume changes during valve closure. We also present a solution in the form of an electropneumatic pressure regulator that can precisely control valve motion. This solution reduces the effect to ∼0.3% even after 10,000 aliquants have been removed from a 10 L reservoir.

  1. Design and development of a pressure relief seating apparatus for individuals with quadriplegia.

    PubMed

    Hefzy, M S; Nemunaitis, G; Hess, M

    1996-01-01

    Persons with spinal cord injury above C7 lack the ability to extend their elbows and grip with their hands. Consequently, when seated, they are unable to press down to shift their weight to relieve pressure on the ischial tuberosities. This can ultimately cause serious pressure sores to develop on the buttocks. Those with adequate insurance coverage can eliminate this problem with an electric power recliner wheelchair. With the touch of a button, the backrest will fold down to a laying position, thus relieving the pressure on the ischial tuberosity. Unfortunately, not all individuals with quadriplegia possess this type of coverage. Therefore, the problem requires an alternate design that will utilize mechanical rather than electrical power to produce a cost-effective solution. The purpose of this project was thus to design and build an affordable apparatus adaptable to wheelchairs that allows individuals with quadriplegia to shift their weight from one side to the other thus relieving the pressure on the ischial tuberosities. A pneumatic system that utilizes two inflatable air bladders was employed. One cushion is placed under each buttock and inflated separately to tilt the user from one side to the other. The inflated cushion elevates one side of the buttock, which relieves the pressure from the other side. The power required to operate the system is generated using repetitions of elbow flexion. The system was evaluated on an individual with C6 quadriplegia. The subject demonstrated independent pressure relief without intrusion on cosmesis or independence.

  2. Effect of transcatheter aortic valve implantation on intraoperative left ventricular end-diastolic pressure.

    PubMed

    Toyota, Kosaku; Ota, Takashi; Nagamine, Katsutoshi; Koide, Yasuhiro; Nomura, Takeshi; Yamanaka, Futoshi; Shishido, Koki; Tanaka, Masashi; Saito, Shigeru

    2016-12-01

    Transcatheter aortic valve implantation (TAVI) for patients with aortic stenosis is a less invasive alternative to surgical aortic valve replacement. Despite this, careful anesthetic management, especially strict control of blood pressure and fluid management, is necessary. During TAVI, normalization of left ventricular afterload due to aortic balloon valvuloplasty and prosthetic valve deployment is expected to result in rapid improvement of systolic function and consequent improvement in diastolic function. However, the early effect of TAVI on left ventricular diastolic function is less clear. We hypothesized that TAVI induces a rapid decrease in left ventricular end-diastolic pressure (LVEDP) after valve deployment. This retrospective observational study included 71 patients who had undergone TAVI using the transfemoral approach with a balloon-expandable valve under general anesthesia. Intraoperative LVEDP was measured using an intracardiac catheter. The severity of residual aortic regurgitation (AR) was assessed using the Sellers criteria. The mean (SD) LVEDP was 17.8 (5.3) mmHg just before TAVI and increased significantly to 27.3 (8.2) mmHg immediately after prosthetic valve deployment (p < 0.0001). The change in LVEDP was 8.7 (8.6) mmHg in patients with low residual AR (Sellers ≤1) and 11.0 (7.1) mmHg in those with high residual AR (Sellers ≥2); however, this difference was not significant. No correlation was found between the LVEDP change and intraoperative fluid balance. In conclusion, LVEDP increased significantly in the early period after valve deployment during TAVI, regardless of residual AR severity. It was suggested that the tolerability of fluid load could be reduced at that time.

  3. Intraoperative testing of opening and closing pressure predicts risk of low intraocular pressure after Ahmed glaucoma valve implantation

    PubMed Central

    Bochmann, F; Kipfer, A; Tarantino, J; Kaufmann, C; Bachmann, L; Thiel, M

    2014-01-01

    Purpose The aim of this study was to assess whether intraoperative testing of silicone Ahmed glaucoma valves (AGVs) would identify valves with an increased risk of low postoperative intraocular pressure (IOP). Methods In 30 consecutive cases of glaucoma surgery with AGV implantation, after priming the AGV, we intraoperatively measured the opening pressure A, closing pressure B, and re-opening pressure C using the active infusion pump of a phako-machine. IOP was checked postoperatively on the same day. Low IOP was defined as <5 mm Hg. Intraoperatively measured pressure characteristics of the valve function were analysed for their ability to predict postoperative IOP outcomes. Results Opening A, closing B, and re-opening C pressures (mean, (SD)) were 18.4 (5.1), 8.3 (4.7), and 11.7 (4.8)mm Hg, respectively. Ten patients (33.3%) had low IOP. An opening pressure of ≤18 mm Hg predicted low postoperative IOP with a sensitivity (10/10) of 100% (95% CI, 69.2–100) and a specificity (13/20) of 65.0% (95% CI, 40.8–84.6). Conclusions AGVs have a high variability of opening, closing, and re-opening pressures. An opening pressure of ≤18 mm Hg, a closing pressure of ≤10 mm Hg, or a re-opening pressure of ≤11 mm Hg identified all patients with low postoperative IOP. PMID:25060848

  4. Pressure Relief Behaviors and Weight-Shifting Activities to Prevent Pressure Ulcers in Persons with SCI

    DTIC Science & Technology

    2014-10-01

    just be reasonable) 20 Upright Sitting upright in the chair without leaning. 60 Beach ball volleyball Bounce the beach ball back and forth...ulcer etiology has demonstrated that the damaging effects of pressure are related to both its magnitude and duration. Based upon this and related...demonstrated that the damaging effects of pressure are related to both its magnitude and duration. Based upon this and related work, clinical

  5. A novel mechanism of cochlear excitation during simultaneous stimulation and pressure relief through the round window

    PubMed Central

    Weddell, Thomas D.; Yarin, Yury M.; Drexl, Markus; Russell, Ian J.; Elliott, Stephen J.; Lukashkin, Andrei N.

    2014-01-01

    The round window (RW) membrane provides pressure relief when the cochlea is excited by sound. Here, we report measurements of cochlear function from guinea pigs when the cochlea was stimulated at acoustic frequencies by movements of a miniature magnet which partially occluded the RW. Maximum cochlear sensitivity, corresponding to subnanometre magnet displacements at neural thresholds, was observed for frequencies around 20 kHz, which is similar to that for acoustic stimulation. Neural response latencies to acoustic and RW stimulation were similar and taken to indicate that both means of stimulation resulted in the generation of conventional travelling waves along the cochlear partition. It was concluded that the relatively high impedance of the ossicles, as seen from the cochlea, enabled the region of the RW not occluded by the magnet, to act as a pressure shunt during RW stimulation. We propose that travelling waves, similar to those owing to acoustic far-field pressure changes, are driven by a jet-like, near-field component of a complex pressure field, which is generated by the magnetically vibrated RW. Outcomes of research described here are theoretical and practical design principles for the development of new types of hearing aids, which use near-field, RW excitation of the cochlea. PMID:24501274

  6. Innovative, High-Pressure, Cryogenic Control Valve: Short Face-to-Face, Reduced Cost

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A control valve that can throttle high-pressure cryogenic fluid embodies several design features that distinguish it over conventional valves designed for similar applications. Field and design engineers worked together to create a valve that would simplify installation, trim changes, and maintenance, thus reducing overall cost. The seals and plug stem packing were designed to perform optimally in cryogenic temperature ranges. Unlike conventional high-pressure cryogenic valves, the trim size can be changed independent of the body. The design feature that provides flexibility for changing the trim is a split body. The body is divided into an upper and a lower section with the seat ring sandwiched in between. In order to maintain the plug stem packing at an acceptable sealing temperature during cryogenic service, heat-exchanging fins were added to the upper body section. The body is made of stainless steel. The seat ring is made of a nickel-based alloy having a coefficient of thermal expansion less than that of the body material. Consequently, when the interior of the valve is cooled cryogenically, the body surrounding the seat ring contracts more than the seat ring. This feature prevents external leakage at the body-seat joint. The seat ring has been machined to have small, raised-face sealing surfaces on both sides of the seal groove. These sealing surfaces concentrate the body bolt load over a small area, thereby preventing external leakage. The design of the body bolt circle is different from that of conventional highpressure control valves. Half of the bolts clamp the split body together from the top, and half from the bottom side. This bolt-circle design allows a short, clean flow path, which minimizes frictional flow losses. This bolt-circle design also makes it possible to shorten the face-toface length of the valve, which is 25.5 in. (65 cm). In contrast, a conventional, high-pressure control valve face-to-face dimension may be greater than 40 in. (>1 m

  7. Excess flow shutoff valve

    DOEpatents

    Kiffer, Micah S.; Tentarelli, Stephen Clyde

    2016-02-09

    Excess flow shutoff valve comprising a valve body, a valve plug, a partition, and an activation component where the valve plug, the partition, and activation component are disposed within the valve body. A suitable flow restriction is provided to create a pressure difference between the upstream end of the valve plug and the downstream end of the valve plug when fluid flows through the valve body. The pressure difference exceeds a target pressure difference needed to activate the activation component when fluid flow through the valve body is higher than a desired rate, and thereby closes the valve.

  8. Time-frequency analysis of transient pressure signals for a mechanical heart valve cavitation study.

    PubMed

    Yu, A A; White, J A; Hwang, N H

    1998-01-01

    A series of transient pressure signals (TPSs) can be measured using a miniature pressure transducer mounted near the tip of the inflow side of a mechanical heart valve (MHV) occluder during closure. A relationship appears to exist between the intensity and pattern of the TPS and the cavitation potential of a MHV. To study the relationship between MHV cavitation and the TPSs, we installed an MHV in a valve testing chamber of a digitally controlled burst test loop. A charge coupled device (CCD) camera and a personal computer based image grabbing program was used to visualize cavitation bubbles appearing on or near the occluder surface. One bileaflet MHV was used as the model for this study. Cavitation bubbles were observed within 300 microsec of the leaflet/housing impact. The valve was tested at various driving pressures between 100 and 1,300 mmHg. MHV cavitation bubble intensities were qualitatively classified into three categories: 1) strong, 2) weak, and 3) none. Digital images of the MHV occluder inflow surface were recorded simultaneously with the TPSs. TPSs were studied by the time-frequency analysis method (spectrogram) and correlated to MHV cavitation potential. The intensity of the cavitation bubbles was found to be associated with burst test loop driving pressures during leaflet closure.

  9. Conductance valve and pressure-to-conductance transducer method and apparatus

    DOEpatents

    Schoeniger, Joseph S.; Cummings, Eric B.; Brennan, James S.

    2005-01-18

    A device for interrupting or throttling undesired ionic transport through a fluid network is disclosed. The device acts as a fluid valve by reversibly generating a fixed "bubble" in the conducting solvent solution carried by the network. The device comprises a porous hydrophobic structure filling a portion of a connecting channel within the network and optionally incorporates flow restrictor elements at either end of the porous structure that function as pressure isolation barriers, and a fluid reservoir connected to the region of the channel containing the porous structure. Also included is a pressure pump connected to the fluid reservoir. The device operates by causing the pump to vary the hydraulic pressure to a quantity of solvent solution held within the reservoir and porous structure. At high pressures, most or all of the pores of the structure are filled with conducting liquid so the ionic conductance is high. At lower pressures, only a fraction of the pores are filled with liquid, so ionic conductivity is lower. Below a threshold pressure, the porous structure contains only vapor, so there is no liquid conduction path. The device therefore effectively throttles ionic transport through the porous structure and acts as a "conductance valve" or "pressure-to-conductance" transducer within the network.

  10. Wear resistant valve

    NASA Technical Reports Server (NTRS)

    Perkins, Gerald S. (Inventor)

    1980-01-01

    A valve which is resistant to wear caused by particles trapped between the valve seat and the valve member or poppet when the valve closes, including an outlet for directing washing fluid at the valve seat and/or sealing face of the poppet and means for supplying pressured fluid to the outlet at the time when the valve is closing.

  11. 49 CFR 179.200-13 - Manway ring or flange, pressure relief device flange, bottom outlet nozzle flange, bottom washout...

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 49 Transportation 3 2012-10-01 2012-10-01 false Manway ring or flange, pressure relief device....200-13 Section 179.200-13 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION...

  12. 49 CFR 179.200-13 - Manway ring or flange, pressure relief device flange, bottom outlet nozzle flange, bottom washout...

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 3 2011-10-01 2011-10-01 false Manway ring or flange, pressure relief device....200-13 Section 179.200-13 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION...

  13. 49 CFR 179.200-13 - Manway ring or flange, pressure relief device flange, bottom outlet nozzle flange, bottom washout...

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 49 Transportation 3 2013-10-01 2013-10-01 false Manway ring or flange, pressure relief device....200-13 Section 179.200-13 Transportation Other Regulations Relating to Transportation (Continued) PIPELINE AND HAZARDOUS MATERIALS SAFETY ADMINISTRATION, DEPARTMENT OF TRANSPORTATION...

  14. Successful application of a PressureWire retrogradely across an ATS prosthetic aortic valve to diagnose constrictive pericarditis.

    PubMed

    Palmer, Sonny; Mariani, Justin A; Newcomb, Andrew; Stokes, Michael B; Burns, Andrew T

    2012-01-01

    Assessment of the left ventricular pressure measured across an aortic valve prosthesis is occasionally necessary when noninvasive imaging and Doppler echocardiographic data are inconclusive or differ from the clinical findings for specific scenarios, such as diagnosing constrictive or restrictive physiology. We present a case in which we safely and effectively replicate the previous successful application of a PressureWire in diagnosing constrictive pericarditis in a patient with a bileafltet mechanical aortic and mitral valves.

  15. Evaluation of a fracture failure mode in the Space Shuttle hydrogen pressurization system flow control valves

    NASA Astrophysics Data System (ADS)

    Hauver, S. E.; Sueme, D. R.

    1992-07-01

    During acceptance testing of the Space Shuttle Endeavor hydrogen flow control valves, which are used in the Orbiter's fuel tank pressurization system, two of the valves experienced fracture of the poppet flange. The poppets are made of 440 C, a high strength, wear-resistant, low ductility, martensitic stainless steel. The investigation which was initiated to determine the cause of these failures is traced. All aspects of the poppet processing that may have introduced a defect were assessed. This included machining, heat treating, passivation, assembly, and test. In addition, several potential failure modes were investigated. The extensive investigation revealed no obvious cause of the failures, but did result in a recommendation for a different material application.

  16. A jazz-based approach for optimal setting of pressure reducing valves in water distribution networks

    NASA Astrophysics Data System (ADS)

    De Paola, Francesco; Galdiero, Enzo; Giugni, Maurizio

    2016-05-01

    This study presents a model for valve setting in water distribution networks (WDNs), with the aim of reducing the level of leakage. The approach is based on the harmony search (HS) optimization algorithm. The HS mimics a jazz improvisation process able to find the best solutions, in this case corresponding to valve settings in a WDN. The model also interfaces with the improved version of a popular hydraulic simulator, EPANET 2.0, to check the hydraulic constraints and to evaluate the performances of the solutions. Penalties are introduced in the objective function in case of violation of the hydraulic constraints. The model is applied to two case studies, and the obtained results in terms of pressure reductions are comparable with those of competitive metaheuristic algorithms (e.g. genetic algorithms). The results demonstrate the suitability of the HS algorithm for water network management and optimization.

  17. Development of high pressure-high vacuum-high conductance piston valve for gas-filled radiation detectors

    NASA Astrophysics Data System (ADS)

    Prasad, D. N.; Ayyappan, R.; Kamble, L. P.; Singh, J. P.; Muralikrishna, L. V.; Alex, M.; Balagi, V.; Mukhopadhyay, P. K.

    2008-05-01

    Gas-filled radiation detectors need gas filling at pressures that range from few cms of mercury to as high as 25kg/cm2 at room temperature. Before gas-filling these detectors require evacuation to a vacuum of the order of ~1 × 10-5 mbar. For these operations of evacuation and gas filling a system consisting of a vacuum pump with a high vacuum gauge, gas cylinder with a pressure gauge and a valve is used. The valve has to meet the three requirements of compatibility with high-pressure and high vacuum and high conductance. A piston valve suitable for the evacuation and gas filling of radiation detectors has been designed and fabricated to meet the above requirements. The stainless steel body (80mm×160mm overall dimensions) valve with a piston arrangement has a 1/2 inch inlet/outlet opening, neoprene/viton O-ring at piston face & diameter for sealing and a knob for opening and closing the valve. The piston movement mechanism is designed to have minimum wear of sealing O-rings. The valve has been hydrostatic pressure tested up to 75bars and has Helium leak rate of less than 9.6×10-9 m bar ltr/sec in vacuum mode and 2×10-7 mbar ltr/sec in pressure mode. As compared to a commercial diaphragm valve, which needed 3 hours to evacuate a 7 litre chamber to 2.5×10-5 mbar, the new valve achieved vacuum 7.4×10-6mbar in the same time under the same conditions.

  18. Assessment of trans-aortic pressure gradient using a coronary pressure wire in patients with mechanical aortic and mitral valve prostheses.

    PubMed

    Kherada, Nisharahmed; Brenes, Juan Carlos; Kini, Annapoorna S; Dangas, George D

    2017-03-15

    Accurate evaluation of trans-aortic valvular pressure gradients is challenging in cases where dual mechanical aortic and mitral valve prostheses are present. Non-invasive Doppler echocardiographic imaging has its limitations due to multiple geometric assumptions. Invasive measurement of trans-valvular gradients with cardiac catheterization can provide further information in patients with two mechanical valves, where simultaneous pressure measurements in the left ventricle and ascending aorta must be obtained. Obtaining access to the left ventricle via the mitral valve after a trans-septal puncture is not feasible in the case of a concomitant mechanical mitral valve, whereas left ventricular apical puncture technique is associated with high procedural risks. Retrograde crossing of a bileaflet mechanical aortic prosthesis with standard catheters is associated with the risk of catheter entrapment and acute valvular regurgitation. In these cases, the assessment of trans-valvular gradients using a 0.014˝ diameter coronary pressure wire technique has been described in a few case reports. We present the case of a 76-year-old female with rheumatic valvular heart disease who underwent mechanical aortic and mitral valve replacement in the past. She presented with decompensated heart failure and echocardiographic findings suggestive of elevated pressure gradient across the mechanical aortic valve prosthesis. The use of a high-fidelity 0.014˝ diameter coronary pressure guidewire resulted in the detection of a normal trans-valvular pressure gradient across the mechanical aortic valve. This avoided a high-risk third redo valve surgery in our patient. © 2017 Wiley Periodicals, Inc.

  19. Passively actuated valve

    SciTech Connect

    Modro, S. Michael; Ougouag, Abderrafi M.

    2005-09-20

    A passively actuated valve for isolating a high pressure zone from a low pressure zone and discontinuing the isolation when the pressure in the high pressure zone drops below a preset threshold. If the pressure in the high pressure zone drops below the preset threshold, the valve opens and allows flow from the high pressure zone to the low pressure zone. The valve remains open allowing pressure equalization and back-flow should a pressure inversion between the two pressure zone occur.

  20. A Simple Method for Noninvasive Quantification of Pressure Gradient Across the Pulmonary Valve

    PubMed Central

    Zhou, Xueying; Xing, Changyang; Feng, Yang; Duan, Yunyou; Zheng, Qiangsun; Wang, Zuojun; Liu, Jie; Cao, Tiesheng; Yuan, Lijun

    2017-01-01

    Pressure gradient across the pulmonary valve (PVPG) is an important hemodynamic variable used in the management of patients with cardiovascular and pulmonary disease. However, a reliable noninvasive method is unavailable. We hypothesized that a progressive Muller maneuver would elicit the pulmonary valve premature opening (PVPO) in diastole and that this event would be detectable by Doppler echocardiography. The intrathoracic pressure (ITP) decrease during this maneuver equals PVPG, which may be assessed with a custom airway pressure measurement device. A total of 102 subjects were enrolled in the study. At the earliest appearance of PVPO, the ITP decrease was recorded as the PVPG. PVPG was also simultaneously measured and compared by other two methods: right heart catheterization in 43 subjects, and routine Doppler echocardiography (pulmonary regurgitation jet) in the other 59 subjects. The results measured by different approaches were compared using the Bland-Altman analysis. PVPG assessed via PVPO showed strong agreement with PVPG measured by catheterization or routine Doppler echocardiography methods, with Lin concordance correlation coefficients of 0.91 and 0.70, respectively. In conclusion, PVPO provides a new noninvasive method of quantification of PVPG. PMID:28198458

  1. A Simple Method for Noninvasive Quantification of Pressure Gradient Across the Pulmonary Valve.

    PubMed

    Zhou, Xueying; Xing, Changyang; Feng, Yang; Duan, Yunyou; Zheng, Qiangsun; Wang, Zuojun; Liu, Jie; Cao, Tiesheng; Yuan, Lijun

    2017-02-15

    Pressure gradient across the pulmonary valve (PVPG) is an important hemodynamic variable used in the management of patients with cardiovascular and pulmonary disease. However, a reliable noninvasive method is unavailable. We hypothesized that a progressive Muller maneuver would elicit the pulmonary valve premature opening (PVPO) in diastole and that this event would be detectable by Doppler echocardiography. The intrathoracic pressure (ITP) decrease during this maneuver equals PVPG, which may be assessed with a custom airway pressure measurement device. A total of 102 subjects were enrolled in the study. At the earliest appearance of PVPO, the ITP decrease was recorded as the PVPG. PVPG was also simultaneously measured and compared by other two methods: right heart catheterization in 43 subjects, and routine Doppler echocardiography (pulmonary regurgitation jet) in the other 59 subjects. The results measured by different approaches were compared using the Bland-Altman analysis. PVPG assessed via PVPO showed strong agreement with PVPG measured by catheterization or routine Doppler echocardiography methods, with Lin concordance correlation coefficients of 0.91 and 0.70, respectively. In conclusion, PVPO provides a new noninvasive method of quantification of PVPG.

  2. Development of a quick reference table for setting programmable pressure valves in patients with idiopathic normal pressure hydrocephalus.

    PubMed

    Miyake, Hiroji; Kajimoto, Yoshinaga; Tsuji, Masao; Ukita, Tohru; Tucker, Adam; Ohmura, Takehisa

    2008-10-01

    Quick and reliable setting of programmable pressure valves (PPVs) is important in the treatment of idiopathic normal pressure hydrocephalus (iNPH), especially for reducing overdrainage complications and related medical costs. A new quick reference table (QRT) was developed for improved PPV control and outcome. Shunt control can be based on the pressure environment in the sitting condition, given as hydrostatic pressure (HP) = intracranial pressure + PPV setting + intraabdominal pressure (IAP). Using this relationship, and estimating HP and IAP from the patient's height and body mass index, respectively, a QRT was designed, consisting of a matrix of the patient's height and weight. The QRT was used to make initial PPV settings in 25 patients with iNPH and the clinical outcomes were evaluated. Postoperative readjustments of the PPV were not necessary in 15 of the 25 patients. At 1 month after operation, the PPV setting was decreased once in 5 patients and increased once in 2 patients. Four of these 7 patients improved after a single readjustment. Three patients required further readjustments. At 3 months after operation, another 3 patients required a single readjustment and all improved after this readjustment. The readjustment rate was 40% and readjustment number was 0.68 times/patient. The mean PPV setting at 1 year after operation was 15.5 +/- 3.9 cmH(2)O. Use of the QRT in non-bedridden iNPH patients results in a low incidence of PPV readjustment.

  3. Depressurization valve

    DOEpatents

    Skoda, G.I.

    1989-03-28

    A depressurization valve for use in relieving completely the pressure in a simplified boiling water reactor is disclosed. The normally closed and sealed valve is provided with a valve body defining a conduit from an outlet of a manifold from the reactor through a valve seat. A closing valve disk is configured for fitting to the valve seat to normally close the valve. The seat below the disk is provided with a radially extending annulus extending a short distance into the aperture defined by the seat. The disk is correspondingly provided with a longitudinally extending annulus that extends downwardly through the aperture defined by the seat towards the high pressure side of the valve body. A ring shaped membrane is endlessly welded to the seat annulus and to the disk annulus. The membrane is conformed over the confronted surface of the seat and disk in a C-sectioned configuration to seal the depressurization valve against the possibility of weeping. The disk is held to the closed position by an elongate stem extending away from the high pressure side of the valve body. The stem has a flange configured integrally to the stem for bias by two springs. The first spring acts from a portion of the housing overlying the disk on the stem flange adjacent the disk. This spring urges the stem and attached disk away from the seat and thus will cause the valve to open at any pressure. A second spring-preferably of the Belleville variety-acts on a latch plate surrounding and freely moving relative to the end of the stem. This second spring overcomes the bias of the first spring and any pressure acting upon the disk. This Belleville spring maintains through its spring force the valve in the closed position. At the same time, the latch plate with its freedom of movement relative to the stem allows the stem to thermally expand during valve temperature excursion.

  4. Control methods and valve arrangement for start-up and shutdown of pressurized combustion and gasification systems integrated with a gas turbine

    DOEpatents

    Provol, Steve J.; Russell, David B.; Isaksson, Matti J.

    1994-01-01

    A power plant having a system for converting coal to power in a gas turbine comprises a coal fed pressurized circulating bed for converting coal to pressurized gases, a gas turbine having a compressor for pressurizing air for the pressurized circulating bed and expander for receiving and expanding hot combustion gases for powering a generator, a first fast acting valve for controlling the pressurized air, a second fast acting valve means for controlling pressurized gas from the compressor to the expander.

  5. Unidirectional Expiratory Valve Method to Assess Maximal Inspiratory Pressure in Individuals without Artificial Airway

    PubMed Central

    Grams, Samantha Torres; Kimoto, Karen Yumi Mota; Azevedo, Elen Moda de Oliveira; Lança, Marina; de Albuquerque, André Luis Pereira; de Brito, Christina May Moran; Yamaguti, Wellington Pereira

    2015-01-01

    Introduction Maximal Inspiratory Pressure (MIP) is considered an effective method to estimate strength of inspiratory muscles, but still leads to false positive diagnosis. Although MIP assessment with unidirectional expiratory valve method has been used in patients undergoing mechanical ventilation, no previous studies investigated the application of this method in subjects without artificial airway. Objectives This study aimed to compare the MIP values assessed by standard method (MIPsta) and by unidirectional expiratory valve method (MIPuni) in subjects with spontaneous breathing without artificial airway. MIPuni reproducibility was also evaluated. Methods This was a crossover design study, and 31 subjects performed MIPsta and MIPuni in a random order. MIPsta measured MIP maintaining negative pressure for at least one second after forceful expiration. MIPuni evaluated MIP using a unidirectional expiratory valve attached to a face mask and was conducted by two evaluators (A and B) at two moments (Tests 1 and 2) to determine interobserver and intraobserver reproducibility of MIP values. Intraclass correlation coefficient (ICC[2,1]) was used to determine intraobserver and interobserver reproducibility. Results The mean values for MIPuni were 14.3% higher (-117.3 ± 24.8 cmH2O) than the mean values for MIPsta (-102.5 ± 23.9 cmH2O) (p<0.001). Interobserver reproducibility assessment showed very high correlation for Test 1 (ICC[2,1] = 0.91), and high correlation for Test 2 (ICC[2,1] = 0.88). The assessment of the intraobserver reproducibility showed high correlation for evaluator A (ICC[2,1] = 0.86) and evaluator B (ICC[2,1] = 0.77). Conclusions MIPuni presented higher values when compared with MIPsta and proved to be reproducible in subjects with spontaneous breathing without artificial airway. PMID:26360255

  6. High pressure capillary micro-fluidic valve device and a method of fabricating same

    DOEpatents

    Crocker, Robert W.; Caton, Pamela F.; Gerhardt, Geoff C.

    2007-04-17

    A freeze-thaw valve and a method of micro-machining the freeze-thaw valve is provided and includes a valve housing, wherein the valve housing defines a housing cavity and includes a housing inlet, a housing vent, a capillary tubing inlet and a capillary tubing outlet. A valve body is provided, at least a portion of which is lithographically constructed, wherein the valve body includes a refrigerant inlet, a refrigerant outlet and an expansion chamber. The expansion chamber is disposed to communicate the refrigerant inlet with the refrigerant outlet and includes a restriction region having a flow restriction. Additionally, the valve body is disposed within the housing cavity to form an insulating channel between the valve housing and the valve body.

  7. Pressurized metered dose inhalers: chlorofluorocarbon to hydrofluoroalkane transition-valve performance.

    PubMed

    Cummings, R H

    1999-12-01

    This article reviews the issues related to the performance of valves in metered dose inhalers with respect to chlorofluorocarbon propellant replacement. Reformulation of existing chlorofluorocarbon-based products with hydrofluoroalkane propellants has been a much more difficult task than initially anticipated, complicated by the need to concurrently develop better performing valves with cleaner extractive profiles. This paper will examine issues related to the reformulation and development of new valves and the tests and procedures used to evaluate valve performance. Evaluation of valve performance will consider the tests performed: mechanisms by which valves fail and analytic testing errors that can complicate the interpretation of results.

  8. System and method for controlling hydraulic pressure in electro-hydraulic valve actuation systems

    DOEpatents

    Brennan, Daniel G; Marriott, Craig D; Cowgill, Joel; Wiles, Matthew A; Patton, Kenneth James

    2014-09-23

    A control system for an engine includes a first lift control module and a second lift control module. The first lift control module increases lift of M valves of the engine to a predetermined valve lift during a period before disabling or re-enabling N valves of the engine. The second lift control module decreases the lift of the M valves to a desired valve lift during a period after enabling or re-enabling the N valves of the engine, wherein N and M are integers greater than or equal to one.

  9. Reduced-impact sliding pressure control valve for pneumatic hammer drill

    DOEpatents

    Polsky, Yarom [Oak Ridge, TN; Grubelich, Mark C [Albuquerque, NM; Vaughn, Mark R [Albuquerque, NM

    2012-05-15

    A method and means of minimizing the effect of elastic valve recoil in impact applications, such as percussive drilling, where sliding spool valves used inside the percussive device are subject to poor positioning control due to elastic recoil effects experienced when the valve impacts a stroke limiting surface. The improved valve design reduces the reflected velocity of the valve by using either an energy damping material, or a valve assembly with internal damping built-in, to dissipate the compression stress wave produced during impact.

  10. 49 CFR 192.201 - Required capacity of pressure relieving and limiting stations.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ...) Each pressure relief station or pressure limiting station or group of those stations installed to... produces a hoop stress of 75 percent of SMYS, whichever is lower; (ii) If the maximum allowable operating... station feeds into a pipeline, relief valves or other protective devices must be installed at each...

  11. 49 CFR 192.201 - Required capacity of pressure relieving and limiting stations.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ...) Each pressure relief station or pressure limiting station or group of those stations installed to... produces a hoop stress of 75 percent of SMYS, whichever is lower; (ii) If the maximum allowable operating... station feeds into a pipeline, relief valves or other protective devices must be installed at each...

  12. 14 CFR 23.841 - Pressurized cabins.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... indicate to the pilot the pressure differential, the cabin pressure altitude, and the rate of change of... rate of flow delivered by the pressure source. The combined capacity of the relief valves must be large... Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION AIRCRAFT...

  13. Functional Heart Valve Scaffolds Obtained by Complete Decellularization of Porcine Aortic Roots in a Novel Differential Pressure Gradient Perfusion System

    PubMed Central

    Sierad, Leslie Neil; Shaw, Eliza Laine; Bina, Alexander; Brazile, Bryn; Rierson, Nicholas; Patnaik, Sourav S.; Kennamer, Allison; Odum, Rebekah; Cotoi, Ovidiu; Terezia, Preda; Branzaniuc, Klara; Smallwood, Harrison; Deac, Radu; Egyed, Imre; Pavai, Zoltan; Szanto, Annamaria; Harceaga, Lucian; Suciu, Horatiu; Raicea, Victor; Olah, Peter; Simionescu, Agneta; Liao, Jun; Movileanu, Ionela

    2015-01-01

    There is a great need for living valve replacements for patients of all ages. Such constructs could be built by tissue engineering, with perspective of the unique structure and biology of the aortic root. The aortic valve root is composed of several different tissues, and careful structural and functional consideration has to be given to each segment and component. Previous work has shown that immersion techniques are inadequate for whole-root decellularization, with the aortic wall segment being particularly resistant to decellularization. The aim of this study was to develop a differential pressure gradient perfusion system capable of being rigorous enough to decellularize the aortic root wall while gentle enough to preserve the integrity of the cusps. Fresh porcine aortic roots have been subjected to various regimens of perfusion decellularization using detergents and enzymes and results compared to immersion decellularized roots. Success criteria for evaluation of each root segment (cusp, muscle, sinus, wall) for decellularization completeness, tissue integrity, and valve functionality were defined using complementary methods of cell analysis (histology with nuclear and matrix stains and DNA analysis), biomechanics (biaxial and bending tests), and physiologic heart valve bioreactor testing (with advanced image analysis of open–close cycles and geometric orifice area measurement). Fully acellular porcine roots treated with the optimized method exhibited preserved macroscopic structures and microscopic matrix components, which translated into conserved anisotropic mechanical properties, including bending and excellent valve functionality when tested in aortic flow and pressure conditions. This study highlighted the importance of (1) adapting decellularization methods to specific target tissues, (2) combining several methods of cell analysis compared to relying solely on histology, (3) developing relevant valve-specific mechanical tests, and (4) in vitro testing

  14. Functional Heart Valve Scaffolds Obtained by Complete Decellularization of Porcine Aortic Roots in a Novel Differential Pressure Gradient Perfusion System.

    PubMed

    Sierad, Leslie Neil; Shaw, Eliza Laine; Bina, Alexander; Brazile, Bryn; Rierson, Nicholas; Patnaik, Sourav S; Kennamer, Allison; Odum, Rebekah; Cotoi, Ovidiu; Terezia, Preda; Branzaniuc, Klara; Smallwood, Harrison; Deac, Radu; Egyed, Imre; Pavai, Zoltan; Szanto, Annamaria; Harceaga, Lucian; Suciu, Horatiu; Raicea, Victor; Olah, Peter; Simionescu, Agneta; Liao, Jun; Movileanu, Ionela; Harpa, Marius; Simionescu, Dan Teodor

    2015-12-01

    There is a great need for living valve replacements for patients of all ages. Such constructs could be built by tissue engineering, with perspective of the unique structure and biology of the aortic root. The aortic valve root is composed of several different tissues, and careful structural and functional consideration has to be given to each segment and component. Previous work has shown that immersion techniques are inadequate for whole-root decellularization, with the aortic wall segment being particularly resistant to decellularization. The aim of this study was to develop a differential pressure gradient perfusion system capable of being rigorous enough to decellularize the aortic root wall while gentle enough to preserve the integrity of the cusps. Fresh porcine aortic roots have been subjected to various regimens of perfusion decellularization using detergents and enzymes and results compared to immersion decellularized roots. Success criteria for evaluation of each root segment (cusp, muscle, sinus, wall) for decellularization completeness, tissue integrity, and valve functionality were defined using complementary methods of cell analysis (histology with nuclear and matrix stains and DNA analysis), biomechanics (biaxial and bending tests), and physiologic heart valve bioreactor testing (with advanced image analysis of open-close cycles and geometric orifice area measurement). Fully acellular porcine roots treated with the optimized method exhibited preserved macroscopic structures and microscopic matrix components, which translated into conserved anisotropic mechanical properties, including bending and excellent valve functionality when tested in aortic flow and pressure conditions. This study highlighted the importance of (1) adapting decellularization methods to specific target tissues, (2) combining several methods of cell analysis compared to relying solely on histology, (3) developing relevant valve-specific mechanical tests, and (4) in vitro testing

  15. Long-term survival rates of gravity-assisted, adjustable differential pressure valves in infants with hydrocephalus.

    PubMed

    Gebert, Anna-Felicitas; Schulz, Matthias; Schwarz, Karin; Thomale, Ulrich-Wilhelm

    2016-05-01

    OBJECTIVE The use of adjustable differential pressure valves with gravity-assisted units in shunt therapy of children with hydrocephalus was reported to be feasible and promising as a way to avoid chronic overdrainage. In this single-center study, the authors' experiences in infants, who have higher rates of shunt complications, are presented. METHODS All data were collected from a cohort of infants (93 patients [37 girls and 56 boys], less than 1 year of age [mean age 4.1 ± 3.1 months]) who received their first adjustable pressure hydrocephalus shunt as either a primary or secondary implant between May 2007 and April 2012. Rates of valve and shunt failure were recorded for a total of 85 months until the end of the observation period in May 2014. RESULTS During a follow-up of 54.2 ± 15.9 months (range 26-85 months), the Kaplan-Meier rate of shunt survival was 69.2% at 1 year and 34.1% at 85 months; the Kaplan-Meier rate of valve survival was 77.8% at 1 year and 56% at 85 months. Survival rates of the shunt were significantly inferior if the patients had previous shunt surgery. During follow-up, 44 valves were exchanged in cases of infection (n = 19), occlusion (n = 14), dysfunction of the adjustment unit (n = 10), or to change the gravitational unit (n = 1). CONCLUSIONS Although a higher shunt complication rate is observed in infant populations compared with older children, reasonable survival rates demonstrate the feasibility of using this sophisticated valve technology. The gravitational unit of this valve is well tolerated and its adjustability offers the flexible application of opening pressure in an unpredictable cohort of patients. This may adequately address overdrainage-related complications from early in treatment.

  16. DECREASES IN VENTRICULAR VOLUME CORRELATE WITH DECREASES IN VENTRICULAR PRESSURE IN IDIOPATHIC NORMAL PRESSURE HYDROCEPHALUS PATIENTS WHO EXPERIENCED CLINICAL IMPROVEMENT AFTER IMPLANTATION WITH ADJUSTABLE VALVE SHUNTS

    PubMed Central

    McConnell, Kathleen A.; Zou, Kelly H.; Chabrerie, Alexandra V.; Bailey, Nancy Olsen; Black, Peter McL.

    2005-01-01

    OBJECTIVE: This retrospective study examined whether changes in ventricular volume correspond with changes in adjustable valve pressure settings in a cohort of patients who received shunts to treat idiopathic normal pressure hydrocephalus. We also examined whether these pressure—volume curves and other patient variables would co-occur with a positive clinical response to shunting. METHODS: We selected 51 patients diagnosed with idiopathic normal pressure hydrocephalus who had undergone implantation of a Codman Hakim programmable valve (Medos S.A., Le Locle, Switzerland). Clinical data were gathered from the patients’ records and clinical notes by an investigator blinded to patients’ ventricular volumes. Ventricular volume was measured using 3D Slicer, an image analysis and interactive visualization software package developed and maintained at the Surgical Planning Laboratory at Brigham and Women’s Hospital. RESULTS: Eighty-six percent of patients with gait disturbance at presentation showed improvement of this symptom, 70% experienced improvement in incontinence, and 69% experienced improvement in dementia. For the group showing 100% clinical improvement, the correlation coefficient of average changes in valve pressure over time (ΔP/ΔT) and average changes in ventricular volume over time (ΔV/ΔT) were high at 0.843 (P < 0.05). For the group experiencing no or only partial improvement, the correlation coefficient was 0.257 (P = 0.32), indicating no correlation between average ΔV/ΔT and average ΔP/ΔT for each patient. CONCLUSION: This was a carefully analyzed modeling study of idiopathic normal pressure hydrocephalus treatment made possible only by adjustable valve technology. With careful volumetric analysis, we found that changes in ventricular volume correlated with adjustments in valve pressure settings for those patients who improved clinically after shunting. This suggests that positive clinical responders retained parenchymal elasticity

  17. Pressure regulation for earth pressure balance control on shield tunneling machine by using adaptive robust control

    NASA Astrophysics Data System (ADS)

    Xie, Haibo; Liu, Zhibin; Yang, Huayong

    2016-05-01

    Most current studies about shield tunneling machine focus on the construction safety and tunnel structure stability during the excavation. Behaviors of the machine itself are also studied, like some tracking control of the machine. Yet, few works concern about the hydraulic components, especially the pressure and flow rate regulation components. This research focuses on pressure control strategies by using proportional pressure relief valve, which is widely applied on typical shield tunneling machines. Modeling of a commercial pressure relief valve is done. The modeling centers on the main valve, because the dynamic performance is determined by the main valve. To validate such modeling, a frequency-experiment result of the pressure relief valve, whose bandwidth is about 3 Hz, is presented as comparison. The modeling and the frequency experimental result show that it is reasonable to regard the pressure relief valve as a second-order system with two low corner frequencies. PID control, dead band compensation control and adaptive robust control (ARC) are proposed and simulation results are presented. For the ARC, implements by using first order approximation and second order approximation are presented. The simulation results show that the second order approximation implement with ARC can track 4 Hz sine signal very well, and the two ARC simulation errors are within 0.2 MPa. Finally, experiment results of dead band compensation control and adaptive robust control are given. The results show that dead band compensation had about 30° phase lag and about 20% off of the amplitude attenuation. ARC is tracking with little phase lag and almost no amplitude attenuation. In this research, ARC has been tested on a pressure relief valve. It is able to improve the valve's dynamic performances greatly, and it is capable of the pressure control of shield machine excavation.

  18. Effects of pressure angle and tip relief on the life of speed increasing gearbox: a case study.

    PubMed

    Shanmugasundaram, Sankar; Kumaresan, Manivarma; Muthusamy, Nataraj

    2014-01-01

    This paper examines failure of helical gear in speed increasing gearbox used in the wind turbine generator (WTG). In addition, an attempt has been made to get suitable gear micro-geometry such as pressure angle and tip relief to minimize the gear failure in the wind turbines. As the gear trains in the wind turbine gearbox is prearranged with higher speed ratio and the gearboxes experience shock load due to atmospheric turbulence, gust wind speed, non-synchronization of pitching, frequent grid drops and failure of braking, the gear failure occurs either in the intermediate or high speed stage pinion. KISS soft gear calculation software was used to determine the gear specifications and analysis is carried out in ANSYS software version.11.0 for the existing and the proposed gear to evaluate the performance of bending stress tooth deflection and stiffness. The main objective of this research study is to propose suitable gear micro-geometry that is tip relief and pressure angle blend for increasing tooth strength of the helical gear used in the wind turbine for trouble free operation.

  19. Achieving Target Pressures with Combined Surgery: Primary Patchless Ahmed Valve Combined with Phacoemulsification vs Primary Phacotrabeculectomy

    PubMed Central

    Sánchez-Noguera, Carmen C; Cárdenas-Gómez, Lorena; Castañeda-Diez, Rafael; Thomas, Ravi; Gil-Carrasco, Félix

    2015-01-01

    ABSTRACT Purpose: To evaluate the ability of phacoemulsification combined with either primary trabeculectomy (PT) or primary Ahmed glaucoma valve implantation (PAVI) to achieve target intraocular pressures (TIOP) in adults with primary open angle glaucoma. Materials and methods: Chart review of 214 adult patients operated between January 2002 and June 2008 with a minimum follow-up of 6 months. Group 1 comprised 181 eyes of 166 patients undergoing PT while group 2 included 50 eyes of 49 patients in combination with primary AVI. Target lOPs were pre-determined for each patient and success was defined as an IOP at or lower than target with or without medications. An IOP above target, loss of light perception or need for additional procedures to lower IOP were considered a failure. Results: Mean preoperative IOP was 17.2 mm Hg in group 1 and 17.3 in group 2. Mean postoperative IOPs were 10.2 and 9.2 on day 1, 12.2 and 11.6 at year 1, and 10.7 in both groups at year 5. Survival rates in groups 1 and 2 were 96.7 vs 96% at 6 months, 89 vs 96% at 12 months, 83.5 vs 96% at 24 months and 79.4 vs 89.1% at 36, 48 and 72 months. Transient bleb leaks were more frequent in group 1 (26 eyes, 14.4 vs 0%, p = 0.001) and transient choroidal detachments were more frequent in group 2 (7 eyes, 3.9 vs 6 eyes, 12%, p = 0.038). Conclusion: Midterm results for achieving target pressures using combined phacoemulsification with either PT or PAVI are comparable. The profile of complications is different for the two procedures. How to cite this article: Albis-Donado O, Sánchez-Noguera CC, Cárdenas-Gómez L, Castañeda-Diez R, Thomas R, Gil-Carrasco F. Achieving Target Pressures with Combined Surgery: Primary Patchless Ahmed Valve Combined with Phacoemulsification vs Primary Phacotrabeculectomy. J Curr Glaucoma Pract 2015;9(1):6-11. PMID:26997825

  20. Rotary pneumatic valve

    DOEpatents

    Hardee, Harry C.

    1991-01-01

    A rotary pneumatic valve which is thrust balanced and the pneumatic pressure developed produces only radial loads on the valve cylinder producing negligible resistance and thus minimal torque on the bearings of the valve. The valve is multiplexed such that at least two complete switching cycles occur for each revolution of the cylinder spindle.