Howdy,
On Tue, 13 Jan 2004, Karl Vacek wrote:
> Compressors used with gas engines, and often high-hp electric
> compressors as well, use unloader mechanisms. The engine or motor turns
> the compressor over constantly, but when the system is up to pressure
> the compressor stops compressing.
>
> Typically, this consists of a pneumatic diaphragm assembly mounted on
> each intake valve, and when the system is up to pressure a valve trips
> and actuates the diaphragm, which holds the intake valves open.
> Exhaust valves are usually spring-loaded rather than cam-operated, so
> with no pressure developed in the cylinders, the compressor just
> breathes in and out of the intakes until more air is needed.
Interesting!
Can unloaders be added to any compressor pump or must the compressor pump
have been designed to accept them?
Internet searches for air compressor unloaders also get a ton of hits for
valves that discharge the pressure in the pump to tank line. I assume
this is just the same name being used for different things?
Do you know of any good sources for a smaller (say 5 cfm at 90 psi?)
single stage pump that has unloaders? I found this on ebay:
http://cgi.ebay.com/ws/eBayISAPI.dll?ViewItem&item=2372509647&category=22662
That's similar to what I'd want, correct?
> Your alternative would be to use a second pop valve on the tank, set a
> bit below the pressure of the safety valve (assuming you have one
> already), and just relieve any excess pressure that way. Less
> efficient, since you're compressing all the time, but for quick and
> dirty, it'll work.
Yeah, I guess I could go that route, but it does seem pretty klugey.
Mark
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