Societe Anonyme Dite: Alcatel Cit

Alcatel Cit

Eric Taberlet

Jean-Francois Vuillermoz

Dominique Guittet

Albert Cacard

The present invention relates to a pumping installation for pumping out an enclosure containing gases which are mixed with solid particles or which generate solid condensates or particles, said installation including a pump equipped with a feed system for supplying an inert purge gas, the pump having its exhaust orifice connected to an evacuation duct, wherein said evacuation duct is connected to said exhaust orifice via a static particle-separator device whose driving flow is solely the exhaust flow of the pump.

Pumping installation for pumping out an enclosure containing gases which

The pump comprises a stator constituted by an alternating sucession of stator plates (22) and stator rings (21) defining a sequence of compression chambers (20), and a rotor assembly comprising two shafts (24, 25) each having a compression lobe (28) in each of the compression chambers (20), with the compression lobes being placed on and fixed to their shafts during assembly of the pump, thereby enabling the axial clearance between each lobe and the adjacent stator plate to be individually adjusted, with each lobe being constituted by a body (29) and a clamping plate (30) which is fixed to the body by screws (34) which compress a set of two conical rings (32, 33), one of which (33) penetrates into the other while being compressed radially, thereby fixing the lobe in place. The assembly melthod consists in using a assembly plate (23) having a portion of extra thickness j penetrating into the stator ring over a distance corresponding to the desired clearance between the lobes and the stator plate (22). The lobes are positioned angularly by means of rods (45) and they are positioned axially by thrusting them against the assembly plate (23) by means of assembly screws (48). Once this has been done, the lobes are fixed to their shafts by tightening the clamping screws (34) which compress the conical rings (32, 33) causing them to clamp against the shaft.

Multistage roots pump and a method of assembling such a pump

A multistage Roots-type vacuum pump comprising: a rotor defining a plurality of successive compression chambers (5) which are axially separated from one another by intermediate plates (1); a rotor assembly disposed inside the stator and constituted by two parallel shafts (8, 9) supported by bearings (11, 12) in end plates (2, 3) of the stator, each shaft (8, 9) being fitted inside each chamber (5) with a compression lobe (13, 14) such that each chamber thus contains two conjugate compression lobes; a motor (15) for driving one (8) of the two shafts in rotation, with the other shaft being driven in the opposite direction by gearing (17-18) situated in a housing (6) fixed to the corresponding end plate (2) of the stator, with each of the shafts passing through the end plate via a corresponding lip seal (19, 20); wherein a sealing module (24) is interposed between the end plate (2) situated adjacent to the housing (6) and the compression chamber adjacent to the housing, the module (24) comprising a partition around each of the shafts (8, 9) and fitted with the fixed portion (25, 26) of a corresponding labyrinth seal, with each shaft being provided with the moving complementary portion (27, 28) of the labyrinth seal, the moving portions of the labyrinth seals being situated in a common cavity (31) of the module, which cavity is connected via a non-return valve (32, 33) to the delivery channel (23) from the compression chamber adjacent to the housing, the valve allowing fluid to flow from the cavity (31) into the delivery channel.

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Annecy-le-Vieux, France

Eric Taberlet