Prv release. - Cannabis Concentrates - International Cannagraphic Magazine Forums

IdahOg · 11-11-2017, 10:38 PM

We operate with a 100# open source steel tank. We have a steel McMaster 150 psi prv on the tank but are considering raising the psi value. Two times we have pressure tested the tank at 140 and 130 respectively and both times the prv was realeased at the end of the tests. Both times the prv released when we were opening a valve on the top of tank to release the air. My experience tells me simply grazing, touching, or working around the prv shouldn't set it off. Due to the prv failing to hold pressure until the conclusion of our tests my partner and I are debating on buying and installing a prv thats rated for 175-200psi.
At times our operating pressure will reach 120-130psi, with that in mind and the pressure test failing should we up the psi on our prv ? Also is there any reason as to why the prv at 150psi would be failing ?

Gray Wolf · 11-12-2017, 11:25 AM

Quote:

Originally Posted by IdahOg

We operate with a 100# open source steel tank. We have a steel McMaster 150 psi prv on the tank but are considering raising the psi value. Two times we have pressure tested the tank at 140 and 130 respectively and both times the prv was realeased at the end of the tests. Both times the prv released when we were opening a valve on the top of tank to release the air. My experience tells me simply grazing, touching, or working around the prv shouldn't set it off. Due to the prv failing to hold pressure until the conclusion of our tests my partner and I are debating on buying and installing a prv thats rated for 175-200psi.
At times our operating pressure will reach 120-130psi, with that in mind and the pressure test failing should we up the psi on our prv ? Also is there any reason as to why the prv at 150psi would be failing ?

All PRV's are not created equal or accurate. We used a certified unit from Swagelok without issues.

HWY36 · 11-16-2017, 05:56 PM

If your prv is failing, the answer is to find a more reliable prv. The answer, I'm sure, is not to increase the blow off pressure. The one that's on there with it's current rating is probably on there at that rating for a reason. Do you know what psi the tank is rated for?

irishf0x · 11-16-2017, 11:49 PM

Graywolf is right.

PRV's are not something to go cheap on. It sounds like your offbrand unit is cracking too early or has a much larger range of cracking pressure.

A swagelok brand PRV is more expensive ($100-200) but they typically wont stick open, even with heavy dumps.

I've been using 900-2000 PSI PRVs through Swagelok and only a couple of customers blew them so many times they stuck open - this was most likely due to product gumming up the assembly.

11-11-2017, 10:38 PM	#1
IdahOg Newbie Join Date: Aug 2017 Posts: 3	Prv release. We operate with a 100# open source steel tank. We have a steel McMaster 150 psi prv on the tank but are considering raising the psi value. Two times we have pressure tested the tank at 140 and 130 respectively and both times the prv was realeased at the end of the tests. Both times the prv released when we were opening a valve on the top of tank to release the air. My experience tells me simply grazing, touching, or working around the prv shouldn't set it off. Due to the prv failing to hold pressure until the conclusion of our tests my partner and I are debating on buying and installing a prv thats rated for 175-200psi. At times our operating pressure will reach 120-130psi, with that in mind and the pressure test failing should we up the psi on our prv ? Also is there any reason as to why the prv at 150psi would be failing ?
	Quote

11-16-2017, 05:56 PM	#3
HWY36 Member Join Date: Feb 2017 Posts: 119	If your prv is failing, the answer is to find a more reliable prv. The answer, I'm sure, is not to increase the blow off pressure. The one that's on there with it's current rating is probably on there at that rating for a reason. Do you know what psi the tank is rated for?
	Quote

11-16-2017, 11:49 PM	#4
irishf0x Newbie Join Date: Jan 2017 Posts: 5	Graywolf is right. PRV's are not something to go cheap on. It sounds like your offbrand unit is cracking too early or has a much larger range of cracking pressure. A swagelok brand PRV is more expensive ($100-200) but they typically wont stick open, even with heavy dumps. I've been using 900-2000 PSI PRVs through Swagelok and only a couple of customers blew them so many times they stuck open - this was most likely due to product gumming up the assembly.
	Quote