PSV Sizing for a PD Pump
PSV Sizing for a PD Pump
(OP)
We have a Positive Displacement Pump on a very old system which requires a new PSV. We have no information on the previous PSV and it has been machined during maintenance over the years. The valve must be set to crack at 17 MPA, the manufacturer has sent us a new valve which is physically about 1/4 of the size of the previous valve although it is set to relieve at 17 MPA. Question is what other parameters need considered given that the orifice through the valve is smaller and inlet and outlet are also smaller.
RE: PSV Sizing for a PD Pump
Good luck,
Latexman
RE: PSV Sizing for a PD Pump
Regards,
SNORGY.
RE: PSV Sizing for a PD Pump
Best regards
Morten
RE: PSV Sizing for a PD Pump
RE: PSV Sizing for a PD Pump
This is speculation but I have run across systems where a relief valve between a pump and a vessel was sized for scenarios that protected both.
It may well be that that the pump alone only requires a small PSV, but another relief scenario is depending on the rate the large PSV provides. A indication this might be the case on older systems is the lack of block valves between pump and vessel, close physical proximity with minimal piping runs, etc...
Take a system approach when evaluating relief valves and sudden size changes such as what you are experiencing here.