Abstract: The invention concerns a damping adapter (3) insertable in a suction duct between a service chamber (2) and a vacuum pump (1). The adapter (3) consists of a tubular duct wall (6) in the form of a flexible bellows surrounded by a damping sleeve (7) supported on two end flanges (4, 5). The flexible bellows' plys (6a, 6b) receive a passive damping elastomer (8a) on their outer faces, engaged between the successive plys (6a, 6b). This considerably reduces the transmitting of vibrations from the vacuum pump (1) to the service chamber (2), enabling applications in the microscopy field in particular.

Abstract: The present invention provides a multistage vacuum pump comprising at least a low pressure first stage and at least a high pressure second stage. At least one of the stages has at least one suction inlet for admitting gas to be pumped, and at least one of the stages has at least one delivery outlet that is open to the outside for exhausting pumped gas. The first and second stages communicate with each other in order to pass gas from the first stage to the second stage. The first stage operates at a flow rate that is smaller than that of the second stage. For an oil-seal rotary vane positive-displacement pump, the oil is injected into the stage having the greater flow rate.

Abstract: The present invention provides a multistage vacuum pump comprising at least a low pressure first stage and at least a high pressure second stage. At least one of the stages has at least one suction inlet for admitting gas to be pumped, and at least one of the stages has at least one delivery outlet that is open to the outside for exhausting pumped gas. The first and second stages communicate with each other in order to pass gas from the first stage to the second stage. The first stage operates at a flow rate that is smaller than that of the second stage. For an oil-seal rotary vane positive-displacement pump, the oil is injected into the stage having the greater flow rate.

Abstract: The invention concerns a damping adapter (3) insertable in a suction duct between a service chamber (2) and a vacuum pump (1). The adapter (3) consists of a tubular duct wall (6) in the form of a flexible bellows surrounded by a damping sleeve (7) supported on two end flanges (4, 5). The flexible bellows' plys (6a, 6b) receive a passive damping elastomer (8a) on their outer faces, engaged between the successive plys (6a, 6b). This considerably reduces the transmitting of vibrations from the vacuum pump (1) to the service chamber (2), enabling applications in the microscopy field in particular.

Abstract: A butterfly valve for limiting sudden variations in gas flow along a duct, the valve comprising a fixed coupling body between two duct ends or between one duct end and a volume, the body constituting a ring whose inside diameter is close to that of the duct, wherein the fixed body is fitted internally with a flap having a circular developed surface, the flap pivoting freely about a diametral shaft, the flap not being plane, but forming a dihedral angle along a ridge that constitutes a chord of the circular developed surface of the flap, the flap being free to rotate without friction relative to the fixed body, and wherein the flap is heavier on one side of the axis than on the other, with the position of the flap resulting from equilibrium between the force due to gravity and the force exerted on the flap by the action of any gas flow, with a flow of gas having the effect of causing the flap to pivot in such a direction as to throttle the duct.

Abstract: 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).

Abstract: 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 aro