The valve is tested every 2 or 3 years. Usually it lifts lower than the set pressure or not at all due to leakby.
We've already considered a lot of possibilities, test rig, pressure reading calibration, human error, procedural guidance, etc. The unfortunate truth is we may never know for...
It was adjusted in March of '06. We are not including the cold set correction. But had we included it, the cold set correction would be 1% I think, which means it still would've failed.
Was the adjustment too recent for this failure cause to be credible?
It's supposed to crack open (initiate lift) at the set pressure +/- 3% or within a range specified by the owner. 10% accumulation is allowed but a verifiable lift beyond just simmering should initiate at the set pressure.
I am evaluating a failure of a relief valve for liquid application to lift at the required set pressure during bench testing. The valve lifted 6% high (636 psi vs. 600 psi set pressure). It is an obsolete Crosby JB-36 valve.
I read some operating experience where an engineer attributed a...
Sorry about the confusion. What I meant was the as-found set pressure when it was tested (on a test bench) was 6% higher than what it was set for (it's as-left pressure). Meaning the valve is supposed to lift at 600 psig and it lifted at 636 psig. Then again at 627 psig. The test medium and...
I am evaluating a failure of a relief valve for liquid application to lift at the required set pressure during surveillance testing. The valve lifted 6% high. It is an obsolete Crosby JB-36 valve.
I read some operating experience where an engineer attributed a failure to lift (lifting high)...
