Backflow valve for screw compressors


2 screw compressors combined 1(30hp)other 1(50hp)each have a tank.

I'm a little confused to why a backflow valve is needed?

30hp is main one used, 50hp is backup.

Pressure is set on 30hp to cut-in 100psi cut-out 125psi.

Pressure is set on 50hp to cut-in 90psi cut-out 125psi.

Comments for Backflow valve for screw compressors

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Jun 01, 2016
Make and Model?
by: Carl

What are the make and models of your screw compressors?

Normally they have an MPV (Minimum Pressure Valve) in built, which does the job you're asking I think?

Jun 01, 2016
check valve (s)
by: Doug in

Might make a difference where they are placed, and how the two machines and tanks are configured.

If nothing else, they may be insurance for the case where an intake (load) valve might fail, and the pressure from the tank(s) might cause oil to be forced back into the intake filter.

Jun 01, 2016
Check valve
by: Bill

Hey Kurt, if you are asking the question because I recommend the use of a check valve when plumbing two tanks or compressors into one air main, this is why.

Typically, when compressors unload, there is an open path to atmosphere from the pump.

If either of your two machines, when they unload, have that open path, then the air from the running compressor will take the easiest path, and that's out the path to atmosphere through the other compressor.

If you have a check valve in each line from each compressor to the main, even if one compressor has an open path to atmosphere, the air from the running compressor cannot flow back down that line and escape.

If neither of your compressors have an open path to atmosphere when at rest, then you most likely don't need an in-line check valve. It's your call based on your knowledge of your compressors.

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