(19)
(11) EP 1 120 568 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
29.08.2001 Bulletin 2001/35

(43) Date of publication A2:
01.08.2001 Bulletin 2001/31

(21) Application number: 01201412.2

(22) Date of filing: 30.08.1996
(51) International Patent Classification (IPC)7: F04C 29/02, F04C 29/10
(84) Designated Contracting States:
DE FR GB NL SE

(30) Priority: 01.09.1995 JP 22532595
27.09.1995 JP 24982995
21.02.1996 JP 3395296

(62) Application number of the earlier application in accordance with Art. 76 EPC:
96306330.0 / 0761975

(71) Applicant: SEIKO SEIKI KABUSHIKI KAISHA
Narashino-shi Chiba (JP)

(72) Inventors:
  • Ijiri, Makoto, c/o Seiko Seiki Kabushiki Kaisha
    Narashino-shi, Chiba (JP)
  • Tohyama,Tatsuhiro, c/o Seiko Seiki K.K.
    Narashino-shi, Chiba (JP)

(74) Representative: Sorenti, Gino et al
Miller Sturt Kenyon, 9 John Street
London WC1N 2ES
London WC1N 2ES (GB)

   


(54) Gas compressor


(57) A valve element (20) is slidably provided midway in an oil passage (18). A discharged jet flow of high pressure refrigerant gas that is from a main body (3) side of the compressor is caused to act on an end face (20a) of the valve element (20). During the compression operation in which the discharged jet flow acts on the valve element (20), by the resulting pressure the valve element (20) is slid against the force of a spring (22) to thereby open the oil passage (18). During the stoppage of the compression operation in which the discharged jet flow is stopped, the valve element (20) is slid by the force of the spring (22) to thereby close the oil passage (18). Thereby, it is possible to prevent a lubricating oil from flowing from an oil pool (17) to a suction chamber (12) side through the oil passage (18) and sliding portions such as an F bearing (4a) and so prevent the occurrence of oil compression in the main body (3) of the compressor at the time of restarting the compression operation.
Alternatively, or additionally, a communication passage (23) linking a discharge chamber (16) side to the suction chamber (12) side is provided. A valve element (22) is provided in the communication passage (23) and is arranged to open the communication passage (23) when the compression operation stops and to close the communication passage (23) when the compression operation starts. Thereby, it is possible to equalise the pressure in the discharge chamber (16) and the suction chamber (12) when the compression operation stops and so prevent a lubricating oil from flowing from the oil pool (17) to the suction chamber side (12) through the oil passage (18) and sliding portions and the occurrence of oil compression in the main body (3) of the compressor at the time of restarting the compression operation.






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