Gas Air compressor

Discussion in 'Shop Talk' started by mikellmikell, May 18, 2006.

  1. mikellmikell

    mikellmikell Well-Known Member

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    What is the valve called on a gass air compressor that unloads the copmressor when it reaches pressure?? where can find one.

    Thanks

    mikell
     
  2. moopups

    moopups In Remembrance

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    That is called a 'blow off' valve, any adequate hardware or supply house should stock them, get an adjustable one.
     

  3. Janon

    Janon 993cc Geo Metro

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    Some of the "blow off" or over-pressure valves are designed as a safety for pneumatic systems in general - they do not automatically reset. I.e. once the valve blows, you have to manually reset it. This is not what you'd want on a gas compressor.

    On an electric compressor you have a pressure limit switch which shuts down the electric motor once pressure is reached - most electric compressors also have an over-pressure safety valve, which under proper working conditions, never gets used... I'm not sure what you have on your particular gas compressor.

    If you take whatever "valve" is on your compressor to a decent pnuematics supply house, they should be able to provide you with an identical performing valve.

    cheers,
     
  4. agmantoo

    agmantoo agmantoo Supporter

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    I think you are referencing an unloader valve. The design of the unloader is not the same for different manufacturers. Northern hydraulics may have a generic one but you will probable have to replumb to get it to work. Try to find one specific to the brand of compressor you have. Check ebay and look at the pics.
     
  5. mikell

    mikell Well-Known Member

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    I don't have a valve I have a compressor and motor .

    mikell
     
  6. Hip_Shot_Hanna

    Hip_Shot_Hanna Well-Known Member

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    if you live near a truck scrap yard some trucks have a unloader that will work
     
  7. ace admirer

    ace admirer Well-Known Member Supporter

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    yeah as others have said: its an unloader valve, i know northern has them for electric motors, grainger might have them for internal combustion.
     
  8. Gideon

    Gideon Well-Known Member

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    After installing I would watch the pressure for a couple of times to make sure it is working properly. From a safety viewpoint, tanks are designed to blow out the ends-I try never to stand at that point-just in case.
     
  9. ericjeeper

    ericjeeper Well-Known Member

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    This valve releases the pressure only on top of the piston. so when the motor kicks back on it is not fighting head pressure.. is not a safety valve of any sort.
     
  10. ace admirer

    ace admirer Well-Known Member Supporter

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    Yeah, running an internal combustion compressor is a lot tricker than an electric...

    a. you must have a good pressure pop off valve to releive pressure when all else fails.

    b. an unloader valve to take pressure off the compressor so that the engine may be cranked easier.

    c. an unloader/throttle/stop run valve or something to regulate running pressure or else live with starting the compressor each time it cycles through a high pressure phase.