Do air operated piston pumps require a pressure relieve valve? 2

[rickfer]

I'm wondering, if I need a pressure relief valve, for an aplication where I transfer oil from a tank to another.

I'm planning to use a graco air operated piston pump, with a 4:1 relation.

Cutsheets from graco don't shown a pressure relief valve, but I was recommended to use it. How ever, I understand that this pump will stop if a high pressure is reach, so i don't see the need to use it.

Am I OK?

 

[JJPellin]

It depends. The most pressure that the pump can deliver is four times the pressure of your air supply. Determine the maximum air pressure as the maximum discharge pressure of the air compressors or the PSV set-point for the air system. Multiply that times four. If the result is high enough to exceed the design limits of the piping down-stream, and if there is any way that the pump discharge could be blocked, then you should add PSV protection.

Johnny Pellin

 

[Compositepro]

One best features of this type of pump is that it will safely stall and stop when the discharge is blocked. This makes operation and control of the pump very simple. If you do need to limit pressure you should do it on the air side of the pump, or use a lower ratio pump.

 

[waross]

Is that 4:1 or 1:4. 1/4 times plant air pressure seems a more reasonable transfer pressure than 4 times plant pressure.

Bill
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"Why not the best?"
Jimmy Carter

 

[psafety]

Graco's go from 4:1 to 56:1 & CompositePro is correct limit/protect on the air side if necessary.