Draining down compressors

[not done it yetParticipant @notdoneityet]

A couple or so points. If second hand, with a plug instead of a valve, I would be hydraulically testing the receiver for integrity – it may have had water sitting in it for some time!

Valves left very slightly open – as in leaking – may well wear like leaky water taps by cutting the seat with the high velocity wet air passing. Agreed not as bad as water cutting brass tap seats, but may occur.

I believe automatic steam traps operated with a bimetallic strip, which opened the valve when the water collected and cooled the valve (water is a poor conductor and any cooling caused the condensate at the lowest point to cool more as colder, insulated, denser condensate then cooled even more quickly thus opening the valve; steam escape almost immediately then heated the valve and it returned to the closed state.

Compressed air is an expensive commodity in terms of cost per unit work done. Leaking it away, however slowly, will mean extra power expense. Even if it is financially acceptable to the user, it is wasting our planet's resources!

[Mark RandParticipant @markrand96270]

I have an Ingersol Rand float operated drain valve. It isn't connected to the compressor yet, but that's because the permanent compressor plumbing is one of next year's projects.

£15 on flea bay .

[peak4Participant @peak4]

Posted by not done it yet on 09/12/2017 05:02:01:

A couple or so points. If second hand, with a plug instead of a valve, I would be hydraulically testing the receiver for integrity – it may have had water sitting in it for some time!

 

No, in this case, It's not a plug instead of a valve. It's a plug with a tapered seat hole and a tapered bolt in it.

i.e. it needs a spanner to drain it, rather than a conventional quick, finger operated, valve;  This is why the first owner left it a gnat's open to ensure it didn't have water sitting in it all the time.

 

Bill

Edited By peak4 on 10/12/2017 01:55:46

[HopperParticipant @hopper]

Posted by peak4 on 09/12/2017 00:46:21:…

I was going to mount the dump/drain valve at the end of a longer length of copper pipe, attached to a union at the base of the tank.

Provided there is a low "swan neck" in the copper pipe, the volume and velocity of the escaping air should clear any condensate quite happily. Being a copper vent pipe, any few remaining drops shouldn't cause corrosion issues either.

I wouldn't use copper pipe for compressed air under full pressure, plus vibration. Steel is more the norm for that application. Copper is not as strong to start with, but also work hardens and the flares break off the ends etc over time.

[DazzaParticipant @dazza]

Hi Peak4,

I have a very large 3 phase compressor in my workshop at work. When the compressor company fitted it, they fitted an air dryer unit to the output of the compressor, as I use it to blow out dust and pressure test from environmental inspection cameras. They also fitted an automatic solenoid valve to the drain at the bottom of the reservoir as the compressor is fitted in a plant room at the rear of the building. This automatic drain is timed to dump into a permanent drain once every 24 hours. I would talk to a compressor supply company and they should be able to point you in the correct direction.

Regards,

Dazza

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