GB1383569A - Minimising power consumption of oillubricated rotary compressors - Google Patents

Abstract

1383569 Rotary positive-displacement machines HOKUETSU KOGYO KK 24 Aug 1972 [25 Aug 1971 21 Dec 1971 14 March 1972 6 April 1972 27 April 1972] 39474/72 Heading F1F An oil sealed and lubricated two-stage screw compressor 11 has a pump 44 which when an unloading valve-member 15 shuts suction ports 13 extracts residual oil and air from a discharge chamber 22. The valve-member 15 is moved by actuating means 34 in response to signals from a pressure detector 32 (shown for convenience at both sides of the Figure) connected to a port 32a at either a suction chamber 14 or a compressed-air reservoir 23 as shown. Said signals also effect operation of valves 36, 39 to reduce the flow oil from the reservoir to the chamber 14 and shut off a passage 38 from an oil pump 25 when the unloading valve closes and moreover, open or close valves 45, 46 in accordance with opening or closing of the unloading valve. Pressure reduction in the chamber 22 by the pump 44 closes a check valve 24. The reservoir contains an oil separator 28. An oil cooler 42 is provided on the suction side of the pump 25. The rotors 17, 21 may be driven by an electric motor 18. A second embodiment, Fig. 2 (not shown), differs in that the residual oil and air are extracted from the chamber 22 by the oil pump, the pump 44 being dispensed with.