Liquid Cylinder Reliefs- Getting it Right

You have a relief on a liquid cylinder that is opening like it is supposed to, but won't reseat properly so you decide to replace it. How are you going to determine what relief to replace it with?

a) Look at the relief that is in the vessel and replace it with one just like it?

b) Look up in the owner's manual and see what it says to do?

c) Look at a reference sheet provided by a reputable provider that translates the 4L-DOT ratings and helps specify the "proper" relief, burst disk and presure gauge for your unit.

"A" is an uncomfortably common response. "B" or "C" are the way to go.

Unfortunately- Information on the maximum pressure settings for reliefs and burst disks or pressure ranges is not obvious or plainly stated on cryogenic liquid cylinder data plates. It requires some knowledge of DOT 4L parlance to know that a 4L-292 liquid cylinder will typically have a 350 psi relief and 0-600 psi pressure gauge. The necessity of looking up information is a problem since most users and many distributors don't have handbooks or reference charts readily available at hand. The risk is that an relief and/or burst disk will be installed that is at too high a pressure for the 4L rating of a vessel. This creates a hazard resulting in a possible explosion of the vessel.

If you need help on determining the right relief, burst disk or pressure gauge for your unit drop me a note. I'll be happy to help.