An oil removal system for an oil-injected screw compressor on helium

The recent emergence of small capacity closed cycle helium refrigeration used in conjunction with industrial superconducting devices has placed great emphasis on the long term reliability of the refrigerator. Formerly the limitations of the refrigeration plant were in the reciprocating expansion machines. With the advent of the gas-lubricated expansion turbine, which, when operated with a reasonably clean gas supply, has a virtually infinite life, the limitations of the compressor have become dominant. Developments are discussed in the improvement of oil removal equipment used in conjunction with a rotary screw compressor having an overall potential reliability of that presently being achieved by the refrigerator turboexpanders. (author)