(19)
(11) EP 0 793 019 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
02.06.1999 Bulletin 1999/22

(43) Date of publication A2:
03.09.1997 Bulletin 1997/36

(21) Application number: 97301303.0

(22) Date of filing: 27.02.1997
(51) International Patent Classification (IPC)6: F04B 25/02, F04B 35/04
(84) Designated Contracting States:
CH DE FR GB LI

(30) Priority: 01.03.1996 GB 9604645

(71) Applicant: The BOC Group plc
Windlesham Surrey GU20 6HJ (GB)

(72) Inventors:
  • Stones, Ian
    Crawley, West Sussex RH10 7FZ (GB)
  • Schofield, Nigel Paul
    Horsham, West Sussex RH13 5SJ (GB)

(74) Representative: Bousfield, Roger James et al
The BOC Group plc Chertsey Road
Windlesham Surrey GU20 6HJ
Windlesham Surrey GU20 6HJ (GB)

   


(54) Improvements in vacuum pumps


(57) A vacuum pump which comprises a multi-stage reciprocating piston mode of operation in which piston reciprocation is effected by electromagnetic drive means and a counter-acting spring means and in which the pump stages are connected in series between a pump inlet and a pump outlet such that, in use, gas being transferred through the pump passes through the stages in turn.






Search report