Air Compressor receiver PSV setting

[napoleon]

Does an air compressor's receiver PSV setting be set to the receiver's maximum allowable pressure (MAWP), or should it be set to the compressor's maximimum discharge pressure?

Regarding high oil level in reciprocating compressors; compressors fail due to the hydraulics created from too much oil in the crankcase. Is this statement accurate?

Thanks in advance for any feedback!

[US Iceman]

Does an air compressor's receiver PSV setting be set to the receiver's maximum allowable pressure (MAWP), or should it be set to the compressor's maximum discharge pressure?

The PSV should have a relief pressure no greater than the receiver MAWP (design pressure). The compressor should also have a maximum design pressure at least equal to the receiver pressure.

I does not hurt anything to have a slightly lower PSV set pressure for the receiver, as long as the set pressure is above the working pressure required.

Regarding high oil level in reciprocating compressors; compressors fail due to the hydraulics created from too much oil in the crankcase. Is this statement accurate?

High oil level in reciprocating compressors will increase the carryover of oil, but no physical damage I'm assuming the oil is close to the top of the sight glass.

If the compressor is completely full of oil and started, the compressor can liquid lock... Then something can break.

[napoleon]

Thanks US Iceman! I appreciate the info!
I invite one to view:
http://www.zero-zone.com/page.asp?page_id=39

what is meant by "hydraulics" in that article?

[TXiceman]

By over filling a compressor crankcase (presuming a recip) you will generally cause the oil to whip or foam due to the oil buing up so high it lets the crank throws, splash the oil. The whipping continues to generate foam amd you will wet the walls of the cylinders excessively and it will get by the rings and will carry out of the compressor. you can eventually get the oil to be all foam and shut down to lack of lubrication, hopefully on the OFS and not a failure.

If the compressor is filled to the brim, you are likely to have a hydraulic lock failuer when you try you start the compressor.

As for the air compressor and receiver, you should never have the compressor PSV higher than the receiver PSV, unless the receiver PSV is also sized to handle the compressor flow. You can apply a PSV with a lower than DWP or MAWP set point on the receiver.

[napoleon]

Thanks TXiceman for the help!

[US Iceman]

what is meant by "hydraulics" in that article?

This was taken from the link provided: "Compressors then fail due to the hydraulics created from too much oil in the crankcase."

This is not very clear or concise, but if I had to guess (and I will) I think they are talking about liquid locking the compressor.

In other words, the compressor is almost, if not entirely full of oil. I can't say that I have seen this before on any multiple compressor rack. However, this is what I and TXiceman were describing before in the earlier threads.

If this happens, you can count on replacing the compressor.

[napoleon]

Thank you US Iceman for clarifying the article in plain terms! I appreciate it!
cheers

Napoleon