Question on regulating air pressure

[Kent A Bathurst]

No - not the usual question re: a regulator to control max pressure.

I am, in fact, looking for the correct gear or terminology to do exactly the opposite.

I need an adjustable "gate valve" if you will. I want to set a pressure on this valve gizmo, and have the gizmo stay closed unless I exceed the set pressure level.

For example - set the gizmo at 85 psi. The gizmo will not open - will allow no air to pass - unless the pressure is greater than 85PSI.

What y'all got for me on this?

All help appreciated.

Thanks

Kent

[Keith Westfall]

So basically, a pressure relief valve?

[Kent A Bathurst]

Hadn't thought of it that way, Keith, but - yeah - I guess that is basically what it acts like.

Are there adjustable versions that have a pressure gauge readout?

Edit -

Annnnd.........we have a winner. Keith - if you ever travel south of the Arctic Circle, your response is worth a couple beers.

To wit: from Mcmaster-Carr:

Adjustable Pressure-Maintaining Relief Valves

Also known as back-pressure regulators, these valves maintain consistent air pressure in your pipeline.

[Jim Neeley]

Kent,

The term you are looking for is "Back Pressure Regulator" (BPR), which you can Google. They are available as self-contained units (like a pressure regulator) or with remote pressure taps, where you run tubing to the the place (typically a tank) you want to limit.

I apply they extensively in my work engineering for the oil field. I use them most commonly to limit the discharge of a positive displacement pump in liquid service, since any valve closure downstream would damage either the pipe or the equipment. They are typically set 10-20% lower than the PSV on the line. The big difference is the BPRs, like regular pressure regulators (and unlike PSVs), are designed for regular use. They do not, however, meet code requirements for overpressure protection.

Just my $0.02... YMMV.

Jim in Alaska