(19)
(11) EP 0 884 480 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
25.08.1999 Bulletin 1999/34

(43) Date of publication A2:
16.12.1998 Bulletin 1998/51

(21) Application number: 97202409.5

(22) Date of filing: 01.08.1997
(51) International Patent Classification (IPC)6: F04D 29/14
(84) Designated Contracting States:
AT BE CH DE DK ES FI FR GB GR IE IT LI LU MC NL PT SE
Designated Extension States:
AL LT LV RO SI

(30) Priority: 11.06.1997 IT TO970510

(71) Applicant: VARIAN S.p.A.
I-10040 Leini (Torino) (IT)

(72) Inventor:
  • Casaro, Fausto
    10141 Turin (IT)

(74) Representative: Robba, Pierpaolo et al
Interpatent, Via Caboto 35
10129 Torino
10129 Torino (IT)

   


(54) Vacuum pump


(57) The invention relates to a vacuum pump to be operated in presence of corrosive gas, comprising a rotor group (1) and a rotatable unit (6, 12, 14) supporting said rotor group (1), wherein a first portion (8a) and a second portion (8b) are defined, both said portions being accessible to the gas and communicating between each other, and wherein disengageable sealing means (22) are provided for preventing the gas passage from said first portion to said second portion or viceversa when said sealing means (22) are engaged.






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