For those of you who might not have known that......

Then how do these compressor limit pressure when they are installed in a frig? Many high pressure compressors operate just fine at their bank-off pressure. (Same with high vacuum pumps.) Limiting, or stopping, the inlet flow just uses the inlet / outlet pressure differential to limit the output pressure.POLAND_SPUD wrote:@ jimmy - I don't think it's the best idea... it'll just limit the flow and put much greater load on the electric motor and all the parts
A closed system can indeed increase pressure indefinately, all you need is sufficient pressure drop through the system. Hydraulic systems are closed circuits and can get to crazy high pressures. Besides, fridges and AC units do have a flow restrictor in the loop, it's the expansion valve. I wonder, could you replace the expansion valve with a regulator and feed the low side of the reg back to the pumps inlet? You would probably need a second regulator to control the inlet of more air if you are actually taking compressed air out of the system.POLAND_SPUD wrote:the amount of refrigerant is limited becasue it is a closed circut... therefore the pressure can't increase indefinately...
AFAIK most fridges run at relatively low pressures (as low as 30 psi) I am not complettely sure if I am right but the fact that fridges have no problems with starting up supports this..
limiting inlet air limits the flow as well so I don't see any point in doing so
well I am not sure about that - I am sure that it will limit flow... but since a needle valve is not a regulator it'll be just a restriction to the flowLimiting the inlet flow will limit the outlet pressure
Then just go down to a scrap yard, rip one out and make your own.ALIHISGREAT wrote:i really want a fridge compressor, and i found a site that sells them new but they are like £80+ and i can't find a source anywhere else
No, that is not true. The maximum pressure you can obtain with a compressor is basically independent of what the working fluid is. Maximum pressure is limited only by the maximum force on the piston and piston area.POLAND_SPUD wrote:@ jimmy - fluids can't be compressed easily - that's why you can get 'crazy pressures' in hydraulic systems.. but it's different with gasses...