Abstract: A vacuum pump unit including a secondary pump sub-assembly (6) rotated by an electric motor M2 and applying suction to a chamber to be evacuated (1), and a primary pump sub-assembly (2) rotated by an electric motor M1 and whose suction is connected to the output of the secondary pump sub-assembly (6), the unit being characterized in that it includes an electronic control circuit (7) for controlling the speed of rotation of the electric motor M1 as a function of to the current I2 drawn by the electric motor M2.

Abstract: A pump enabling a molecular vacuum to be reached, the pump comprising a stator and rotor assembly comprising two rotors having parallel shafts rotating in opposite directions, the stator including a suction inlet and a delivery outlet, wherein the pump is split axially into a first zone situated at its suction end, followed by a second zone, said first zone being of the turbomolecular type having fins and two rotors, said second zone being of the type having two screws or two rotary pistons on parallel shafts, one of the shafts being driven by a motor and the other being driven by a transmission.

Abstract: A pumping assembly for obtaining a high vacuum, the assembly comprising a primary pump (4) and a secondary pump (1) associated in series, the inlet of the secondary pump (1) being taken from an enclosure (3) to be evacuated, the assembly further including means (7) for starting the secondary pump (1) when the pressure upstream from the primary pump (4) drops below a value P.sub.1, the assembly being characterized in that a passive tank (10) followed by an isolating valve (11) are interposed between the outlet (12) from the secondary pump (1) and the inlet (13) to the primary pump (4), and in that it includes control means (7) for closing the isolating valve (11) and stopping the primary pump (4) when the pressure in said passive tank (10) reaches a value P.sub.2 <P.sub.1, and for opening the isolating valve (11) and restarting the primary pump (4) when the pressure in said passive tank ( 10) returns to the pressure P.sub.1.

Abstract: A rotary vacuum pump comprising a stator (1) and a rotor (2), the rotor being rotated inside the stator and the stator including a suction inlet (11) and an exhaust outlet orifice (12), wherein the suction end of the rotor carries at least one wheel (13) having sloping vanes (14) such that any solid particles that may be sucked in are projected thereby in a radial direction towards an annular stator collector tank (15) having a circular opening (16) opening out into the stator cavity (6) and situated in the plane in which said particles are projected by said vanes (14).

Abstract: A molecular high-vacuum pump has a bell-shaped rotor 5 including a shaft supported by roller bearings 12, 13 disposed inside the bell rotor. The stator 1, 6 defines two converging pumping stages, one in cooperation with the inner cylindrical surface 10 of the rotor and the other in cooperation with the outer cylindrical surface 9 of the rotor. The suction inlet 3 is disposed in the apex area 4 of the bell rotor. The discharge outlet 11 of the pump is disposed in the vicinity of the lower rim of the bell, and both pumping stages transfer gases towards this rim. In this way, gases introduced through the inlet 3 into the pump cannot penetrate into the motor space 15 and damage the bearings of the pump.

Abstract: An installation for detecting a leak of a tracer gas, the installation comprises a mechanical primary pump (5) whose inlet is connected firstly to a part (9) under test via a first valve (2), and secondly to the outlet (17) of a turbo-molecular secondary pump (7) via a second valve (3), with the inlet of said turbomolecular pump being connected to the part under test via a third valve (4), and with a spectrometer cell (1) being also connected to the inlet side of said turbomolecular pump. The installation includes the improvement whereby said turbomolecular pump is constituted by two stages in series, with the connection between the two stages having an intermediate inlet orifice (16) connected thereto and also connected to the part under test (9) via a fourth valve (12), with the first stage connected to the spectrometer cell (1) having a high helium compression ratio, and with the second stage connected to the primary pump (5) having a high nitrogen throughput.

Abstract: A high vacuum rotary pump comprising a rotor (3) mounted in a stator (1) having a suction end (5) and an exhaust end, the exhaust end being pierced by an exhaust orifice (6) intended for connection to the suction end of a primary pump, said rotor being drivable coupled to a motor (8, 10) housed in a sleeve (11), said sleeve extending the exhaust end of said stator and having the same internal pressure as the exhaust end of the stator, the rotating members of said motor and rotor being supported by bearings (12, 13), and the far end of the sleeve from its end adjacent to the stator being closed by an end plate (14), the pump including the improvement whereby an orifice (16) for rapidly returning the stator to atmospheric pressure is provided in said sleeve in such a manner as to avoid oil vapor being introduced into the stator from the primary pump when the pump is stopped, said orifice being provided with a valve which is closed during operation of the pump and which is open only when the pump is stopped.

Abstract: A hard vacuum pump of the type having a pump body (4) to which a multi-stage stator (3) and a multi-stage rotor (2) mounted on a shaft (1) are connected, said shaft (1) being driven by a motor and rotating in at least two ball bearings (5, 6) disposed in a sleeve (18) formed by an extension of said pump body (4), a dynamic molecular seal (7) being set on said shaft (1) at the body end of the sleeve (18), wherein the opposite end (11) of the sleeve (18) is closed, a nozzle (8) communicating with an outside source of gas being provided at said closed end (11), said pump body (4) also being connected to an exterior primary vacuum pump whereby said ball bearings (5, 6), and the rotor (9) of said motor are permanently swept by said gas entering via said nozzle and leaving via said dynamic seal, said gas flowing at a pressure intermediate between atmospheric pressure and the pump discharge pressure.The invention is used in microelectronics techniques.

Abstract: The invention relates to a high-speed hard vacuum rotary pump. A hard vacuum rotary pump which includes a rotor (2) driven by a motor (20) disposed on the outside of the pump body and connected to the motor by a drive shaft (1) which is sealed by a grooved dynamic seal (8) is characterized in that said shaft is supported firstly by an outer bearing (6) disposed on the outside of the pump body (4) and secondly by an inner bearing (5) disposed inside the pump body and lubricated with grease. The invention applies in particular to molecular and turbomolecular vacuum pumps.