PSV spillback sizing
PSV spillback sizing
(OP)
Does anybody knows what is sizing a PSV for spillback?
Thanks
Thanks
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RE: PSV spillback sizing
RE: PSV spillback sizing
RE: PSV spillback sizing
The problem is what suction pressure do I select and discharge pressure to calculate volume (or mass). The discharge is easy, its the MOAP of the piping and the relief pressure. Ok, suction pressure. If the normal pressure is P1 and the cylinder can move V1, then the relief valve is sized for V1. But what happens if P1 is increased to 2 times P2, then the volume will be slightly more than 2 times P1 (more because volumetric effiency should be going up). OH, but at V2 the horspower almost doubles and the engine or motor will trip and the volume will go to zero, OR the spill back valve will only allow a volume of .5 V1 plus the original V1.
The relief valve must sized relieve the greater of a volume that will not overload the driver (pick a value of maybe 120% of maximum avaiable HP) or the volume available plus the volume that the spillback valve can pass.
RE: PSV spillback sizing
So proceed doing sizing like we do for control valve fail open.
RE: PSV spillback sizing
Or
ASCV on 2nd stage compressor (which also work as recycle / spillback on high discharge pressure) failed open causing tremendous flow to PSV on 1st stage discharge ?
Or...
I guess the best is refer to originator...
JoeWong