PSV in series
PSV in series
(OP)
Is there a code specifically preventing two pressure relief devices in series?
Hypothetically could you send the psv of say a vessel to a tank which has a pvrv venting to atm?
Assume inlet and outlet losses meet code for both the psv and the pvrv, for all design cases.
Thanks to all.
Hypothetically could you send the psv of say a vessel to a tank which has a pvrv venting to atm?
Assume inlet and outlet losses meet code for both the psv and the pvrv, for all design cases.
Thanks to all.





RE: PSV in series
As far as i know there is no direct prohibition in relevant codes having PSVs in series; but there are many strong preventing notes having no excessive back pressure than limited in PSV relieving conditions. Then, in my opinion, at first it's recommended having no PSVs in series at all but if one has to have such configuration it should be studied by a reputable risk assessment/analysis to make a safe and proper decision...
RE: PSV in series
RE: PSV in series
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RE: PSV in series
The bottom line is that this is a perfectly allowable practice. The important point is that the relief devices have to meet all the relevent design criteria (sufficient capacity, piping pressure loss, proper valve selection for the resulting superimposed backpressure).
Codes leave broad discretion to the user to do what makes sense for specific applications. Codes purposely don't say what you can and can't do in terms of application design.
RE: PSV in series
I need your advice for below query.
We have one Lube oil PSV(Conventional design), which is located in one compressor. PSV set pressure is 11Kg/cm2g and there is 1 atm(stad)g Constant back pressure. While calculating CDTP, is it required to deduct the constant back pressure?
Or CDTP is same as Set pressure?
If the constant back pressure is atmospheric, is it required to consider while calculating the CDTP?
PZV data sheet is attached for your reference.
Pls advice us as soon as possible.