PSV leaking by?
PSV leaking by?
(OP)
Hey guys...For Crude oil application, we have a pilot operated pressure relief valve, set pressure of 235 psi, which has recently been "leaking by" with only 14-15 psi on the line. What are possible causes of this? There is a filter screen installed in the pilot sense line which may be plugged or clogged with debris, this is my thought...any other thoughts as to what may be causing this? The main valve has been sent in for service and cleaning once before after a similar issue.





RE: PSV leaking by?
There are however, three possible leak paths through the main valve. If the Pilot is leaking, you probably have bad seals (o-rings). However, if the Main Valve is leaking, you may be leaking beneath the nozzle, across the seats or through the dome (down along the sides of the piston (disc). If you put the valve on a test bench and pressurize the body to about 50% of set, then you can do a test to determine the leak path. Cover the outlet partially and pour water in the bowl of the body (just enough to cover the connection between the body and the nozzle). If you get bubbles there, you have a leak beneath the nozzle. Tough to fix. Sned to factory for repair. If no bubbles, then fill to above seat level. If bubbles appear, then disassemble and replace seat O-Ring. Problem solved. If no bubbles at seat, continue to fill body above where Piston and sleeve intesect. Bubbles there mean the dome pressure is getting past the piston rings. Disassemble and replace piston rings. Problem solved. That is a quick explanation. I hope it helps.
JAC
RE: PSV leaking by?
RE: PSV leaking by?
JAC