ATBECHDEDKESFRGBGRITLILUNLSEMCPTIESILTLVFIRO....AL..............................RDIM360 (Ver 1.5 21 Nov 2005) - 1100000/00884480EUROPEAN PATENT APPLICATIONA319990825EP97202409.519970801itenenTO970510 19970611IT19990825199934199812161998516 6F 04D 29/14 AdeVakuumpumpeenVacuum pumpfrPompe à vide1VARIAN S.p.A.002801109586.03/EP/BEVia Varian 54I-10040 Leini (Torino)ITCasaro, FaustoC.so Racconigi, 10110141 TurinITRobba, Pierpaoloet al00084201Interpatent, Via Caboto 3510129 TorinoITATBECHDEDKESFIFRGBGRIEITLILUMCNLPTSEALLTLVROSI19990825199934

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.