Compressor Problem

Questions & AnswersCompressor Problem
Cas Staff asked 4 years ago

Dear Sir,

I have Ingersoll Rand 15kw screw air compressor problem is this that falling the oil from intake valve when shutdown the compressor after 3 minute unload.

I start the compressor and when the compressor fills the tank and reaches setting pressure of 7.5 bar, than the compressor runs in unload position.

After 3 minute compressor motor shuts down and when the extra pressure is released from intake valve,t here is some oil falling when releasing the air.

kindly help me what i do? where is the problem in intake or minimum pressure..

Thanks With Regards,

Mubasher Mehmood

1 Answers
Cas Staff answered 4 years ago

Hello Mubasher,

This is a problem that happens quite a lot with rotary screw air compressors.

It can have two causes:

1) The inlet valve closes too slowly or doesn’t close completely.

When the motor stops, the pressure from the air tank will flow back through the compressor element and try to escape backwards through the inlet valve. If the valve isn’t completely closed, it will spit out a lot of oil with it.

2) The check valve below the screw element (also called oil stop valve) is stuck. When the compressor stops, this valve should stop almost all of the oil/air pressure that tries to flow back to the compressor element. When this valve stays open, it will all flow back into the element and tries to escape back through the inlet valve.

3) At shutdown, the air in the receiver is blown down through a small valve on the inlet valve. Normally, this air should be oil free, as it is located after the oil separator. When the oil separator is dirty and old, the air will still contain oil.

But, if this is the case you should also have lots of oil in your compressed air system.

In my experience, most of the time it’s a problem with the inlet valve that is not closed completely.

Good luck and let me know if you need any more help.

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