Oil/Water Correlation for PRV (Pressure Relief Valves): Is the Measured Set Pressure the Same on Water Compared to Diesel Fuel, Lubricating Oil, etc.?

Author(s):  
Robert J. O’Neill

In verifying PRV setpoints, it is important to distinguish if there is any differential (±) between the measured SP (Set Pressure) of a PRV when tested on water versus testing on other fluids such as Diesel Fuel or Lubricating Oil. It is also important to recognize the standard test medium used by the PRV industry for liquid service testing is water. SP testing with other fluids involves issues such as possible serious health and safety as well as equipment cross contamination. Paper published with permission.

1999 ◽  
Vol 122 (1) ◽  
pp. 60-65 ◽  
Author(s):  
A. J. Pierorazio ◽  
A. M. Birk

This paper presents the results of the first full test series of commercial pressure relief valves using the newly constructed Queen’s University/Transport Canada dynamic valve test facility (VTF) in Maitland, Ontario. This facility is unique among those reported in the literature in its ability to cycle the valves repeatedly and to measure the time-varying flow rates during operation. This dynamic testing provides much more insight into valve behavior than the single-pop or continuous flow tests commonly reported. The facility is additionally unique in its simulation of accident conditions as a means of measuring valve performance. Specimen valves for this series represent 20 each of three manufacturers’ design for a semi-internal 1-in. 312 psi LPG relief valve. The purpose of this paper is to present the procedure and results of these tests. No effort is made to perform in-depth analysis into the causes of the various behaviors, nor is any assessment made of the risk presented by any of the valves. [S0094-9930(00)01201-4]


2005 ◽  
Vol 6 (5) ◽  
pp. 433-442 ◽  
Author(s):  
A Sakai ◽  
H Takeyama ◽  
H Ogawa ◽  
N Miyamoto

The charge mixture in a premixed charge compression ignition (PCCI) engine with direct in-cylinder injection early in the compression stroke is still heterogeneous even at the compression end. Direct injection of a low-volatility fuel, such as diesel fuel, early in the compression stroke results in adhesion of unevaporated fuel on the cylinder liner wall. It may be possible to improve both mixture formation and homogeneity, and decrease wall wetting by using higher-volatility fuels with distillation temperatures lower than the in-cylinder gas temperature early in the compression stroke. This research addressed the potential for improvements in early direct injection type PCCI combustion with a higher-volatility fuel, experimentally and computationally. A normal heptane + isooctane blended fuel with ignitability similar to diesel fuel in PCCI operation was used as the higher-volatility fuel. The experimental results showed that the deterioration in thermal efficiency that occurs with advanced injection timings with ordinary diesel fuel could be eliminated with the higher-volatility fuel without significantly altering the total hydrocarbons (THC) and CO emissions. With early injection timings, the rate of heat release with diesel fuel is smaller than with higher-volatility fuels. This result suggests that with diesel fuel there is significant fuel adhesion to the cylinder liner wall and also absorption into the lubricating oil.


Author(s):  
Julia V. Bukowski ◽  
Robert E. Gross ◽  
William M. Goble

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.


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