Patent ID: 7588417

Claim:
A turbomolecular pump having a multistage peripheral stator of vanes engaged between the blades of a multistage central rotor ( 18 ), in which: the stator comprises a plurality of stator vane sectors ( 26 a - 26 j ; 27 a - 27 j ) assembled about the rotor ( 18 ); the stator vane sectors ( 26 a - 26 j ; 27 a - 27 j ) are distributed in a plurality of axial rows of stator vane sectors ( 26 , 27 ); and each axial row of stator vane sectors ( 26 , 27 ) is secured to a peripheral shell sector ( 24 , 25 ), thereby forming a multistage sector for a stator; wherein: each stator vane sector ( 26 a - 26 j ; 27 a - 27 j ) comprises an individual element; the stator vane sectors in the same axial row of stator vane sectors ( 26 , 27 ) are fitted and secured to the concave inside face of the corresponding peripheral shell sector ( 24 , 25 ) so as to build up the multistage sector for the stator; the concave inside face of the peripheral shell sector ( 24 , 25 ) includes retaining means ( 24 a - 24 j ) for individually retaining the stator vane sectors ( 26 a - 26 j ) in position; and wherein the peripheral shell sector covers a full axial length of the stator.