S econd stage safety valve blows on high pressure compressor


High pressure compressor

High pressure compressor

Hello Sir,

I've faced a problem related to second stage safety valve blows @ 70 BAR pressure. this is high pressure compressor having three stages. first stage can develop 10 BAR, second stage can develop 40 BAR and third stage can develop 300 BAR.

During over hauling we have replaced 2nd stage and 3rd stage piston with piston ring, first stage reed valve, 2nd stage intake and exhaust valve. 3rd stage intake & exhaust valve and 2nd stage safety valve.

Compressor configuration:

First stage discharge to second stage suction through inter cooler pipe , second stage discharge to moisture separator- moisture separator to 3rd stage intake- 3rd stage outlet to after cooler pipe after cooler to separator , separator to discharge filter then final compressed air.

2nd stage safety valve fitted on the separator body.

now when we have started compressor and when it reaches 70 BAR pressure the 2nd stage safety continuously blowing and pressure not developing. to re-check the operation of 3rd stage valve we have disconnected the after cooler tube joint and run the compressor. we felt pressure from 3rd stage outlet, so we assume that the 3rd stage valves are working properly.

we can not understand that why new 2nd stage safety valve blows . Please help us to short out the matter.

Thanks & Regards,

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Jun 15, 2016
2nd stage of 3 stage blows PRV
by: Doug in s.d.ca

The 70bar is at the output of the 3rd stage when the prv blows?

While you think the 3rd stage is working, clearly there must be some (or a lot) of back flow from stage 3 to stage 2, so there's probably leakage from 3rd stage intake valve.

If that sounds way off, please clarify or restate the problem.

Good luck.

BTW, nice looking piece of machinery. What's it for?

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