Abstract: A dry vacuum pump includes: at least one oil sump; at least one pumping stage; two rotary shafts respectively supporting at least one rotor extending into the at least one pumping stage, the rotors being configured to rotate in a synchronized manner in the reverse direction in order to convey a gas to be pumped between an intake and an outlet of the vacuum pump, the shafts being supported by bearings lubricated by a lubricant contained in the at least one oil sump; at least one lubricant sealing device interposed between the at least one oil sump and a pumping stage at the shaft passage; and at least one expansion device configured to reduce the pressure variations between a pumping side volume and the at least one oil sump.

Abstract: A dry vacuum pump includes: at least one oil sump; at least one pumping stage; two rotary shafts respectively supporting at least one rotor extending into the at least one pumping stage, the rotors being configured to rotate in a synchronized manner in the reverse direction in order to convey a gas to be pumped between an intake and an outlet of the vacuum pump, the shafts being supported by bearings lubricated by a lubricant contained in the at least one oil sump; at least one lubricant sealing device interposed between the at least one oil sump and a pumping stage at the shaft passage; and at least one expansion device configured to reduce the pressure variations between a pumping side volume and the at least one oil sump.

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 relates to a system for regulating the pressure in an enclosure (1) that is to contain processed gas for manufacturing semiconductor components or micro- or nano-technology devices, the enclosure being connected by pipework (2) to a pump unit (3) comprising a dry mechanical primary pump (4) and at least one secondary pump (5). According to the invention, the system further comprises a speed controller (6) controlling simultaneously the speeds of rotation of the dry mechanical primary pump (4) and of said at least one secondary pump (5).