Abstract: The invention relates to a gas friction vacuum pump having at least two differently configured pump stages each having a rotor section and a housing section. In order to adapt the pump to different applications, the pump stages are detachably connected with each other so that different inlet stages can be mounted on the high-vacuum side.

Abstract: A friction pump includes a generally cylindrical first housing part, a generally cylindrical second housing part projecting axially into the inner space of the first housing part; a bearing mounted in the second housing part coaxially therewith; and a pump rotor supported for rotation in the bearing. The pump rotor has a cylindrical shell surrounding the second housing part. The pump further has a drive motor mounted in the second housing part for driving the pump rotor; and a helical channel defined between the inner face of the first housing part and the outer face of the pump rotor for pumping gases upon rotation of the pump rotor. The second housing part, the bearing, the pump rotor and the drive motor form a single structural unit that can be axially removed from the first housing part after releasing a coupler between the two housing parts.

Abstract: A housing 3 disposed below the rotor accommodates a driving motor 13, shaft bearings 14, 15 and an oil sump 21. An evacuating line 31 which traverses the wall the housing 3 connects a vacuum pump to the interior 18 of the housing. In order to avoid the loss of oil in the housing or the bearings, the evacuating line 31 and the oil sump 21 are directly connected.

Abstract: A vacuum pump has a pump housing, magnetic bearings mounted in the housing, a rotary assembly including a pump rotor disposed in the housing and supported for rotation by the magnetic bearings and two spaced emergency bearings supporting the pump rotor when it deviates by a predetermined extent from a desired position. The rotary assembly has a center of gravity which is situated between the emergency bearings and which is spaced approximately equally therefrom.

Abstract: A gas friction pump has an inlet arranged to be coupled to a vessel to be evacuated; an outlet and an outlet-side pumping stage formed of a helical gas pumping channel. The pump further has a scavenging gas inlet circumferentially surrounding the helical gas pumping channel for exposing the channel to a scavenging gas.

Abstract: A twin-shaft vacuum pump includes a pump chamber, a pair of rotary pistons disposed in the pump chamber, and plates which laterally delimit the pump chamber, and a housing ring which peripherally delimits the pump chamber. In order to increase the ability of the pump to withstand thermal stresses, the housing ring and the rotary pistons are made of different materials, with the coefficient of expansion of the piston material being lower than the coefficient of expansion of the housing material. Other improvements include cooling of the lateral end plates, cooling of the rotors, and the provision of sleeves which serve to fix the position of the rotors on the shafts and which are composed of a material whose coefficient of expansion is lower than that of the rotor material.

Abstract: A high-vacuum pump includes a plurality of pump stages, each of which has a rotor and a stator. In one of the pump stages, either the rotor or the stator is provided with a structure that effects the gas conveying includes radially extending webs whose pitch and width decrease from the suction side of the pump stage to the thrust side of the pump stage.

Abstract: A dual-shaft machine comprising a housing, two pistons rotatably mounted in the housing leaving a cold play spacing between one another and said housing, and a coating provided on either the housing or the pistons, or both, to reduce the cold play spacing to that required by the intended field of use of the machine.

Abstract: Rotating unit including a shaft, a blower rotor, and a motor armature is removable as a unit from the motor housing. The diameter of a first resiliently mounted bearing holder toward the blower rotor is larger than the diameter of the armature, which in turn is larger than the diameter of a second resiliently mounted bearing holder remote from the blower rotor.

Abstract: A lubricating system for supplying oil to the bearings of a shaft having a central oil pumping passage open at one end. An oil delivery tube reaches into the oil pumping passage. To achieve a positive transfer of the oil from the oil delivery tube to the inner wall of the oil pumping passage, means are associated with the upper end of the oil delivery tube for bringing the oil onto the inner wall of the oil pumping passage.

Abstract: A device for moving a gas at a subatmospheric pressure with a screwthread-like device on at least one of the facing surfaces of a rotor spacedly surrounded axially by a relatively-rotatable stator insulates the stator from a housing for the device to prevent thermal variation of the space between the rotor and stator and, thus, keeping the gas-moving action constant.

Abstract: A two-shaft vacuum pump which draws gas in at an inlet and compresses it at a first outlet for discharge, thereby producing a vacuum at the inlet, has a second, pressure-responsive outlet from the area where the gas is compressed for discharge from the first outlet. The second outlet thereby relieves excess, compression gas pressure which could overload the pump motor, for example, at the start of operation when high-density gas is drawn in for compression.

Abstract: A vacuum pump includes an evacuation chamber, a gear chamber, a partition separating the evacuation chamber from the gear chamber, a rotary pump shaft extending through the partition and having one end connected to a vane arranged for rotation in the evacuation chamber and having another, opposite end extending into the gear chamber, a shaft bearing surrounding the pump shaft and received in the partition, a labyrinth seal surrounding the pump shaft and received in the partition for sealing the evacuation chamber from the gear chamber, an oil sump defined in the gear chamber for accommodating oil therein, an evacuation device for generating a vacuum in the gear chamber and an oil loss preventing arrangement for avoiding an oil deficiency in the gear chamber due to the vacuum generated therein.

Abstract: A rotor for a rotary slide-vane vacuum pump and a method of producing same comprises providing two rotor sections, each having a shaft stub, a rotor portion and a plane or contact surface produced by lathing, forming axial slot portions for accommodate one or more slide vanes through the contact surfaces, assembling the two rotor sections by the use of an assembling jig and fixedly joining the sections together and finishing the external surfaces of the assembled rotor with respect to at least one of length and diameter while the rotor is held in one and the same fixture.

Abstract: A vacuum pump comprises a suction nipple valve including a cylinder, a piston slidably received therein and a movable valve closing member operatively connected to the piston. The vacuum pump further has a pressure medium conduit having a first end communicating with the cylinder; an inlet opening at a second end of the conduit for pressure medium to flow through the inlet opening to the piston; a control arrangement for closing and opening the inlet opening dependent upon run or standstill of the vacuum pump. In the closed state of the inlet opening an oil quantity is maintained above the inlet opening.

Abstract: A displacement machine operating according to the spiral principle has at least one parallel motion guide device provided to ensure a torsionally rigid relative movement of two displacement elements.

Abstract: In a displacement machine operating according to the spiral principle and having two displacement elements presenting respective axially interengaging sprial-shaped walls, and drive means connected between the elements to produce a relative translatory circular movement therebetween, an elastic suspension is provided to support at least one of the displacement elements for permitting elastic movement between the elements in a plane perpendicular to the axis of translatory circular movement.In such a displacement machine, whether or not the elastic suspension is provided, the walls of the displacement elements are preferably made, at least at the surfaces contacting one another, of respectively different materials presenting a low mutual coefficient of friction.

Abstract: A dynamic packing for sealing a shaft which passes through a wall separating an oil-containing space from an oil-free space or from the outside atmosphere, composed of two shaft sealing rings which engage the shaft and define an oil-filled gap therebetween, and a duct composed of one portion in communication with the oil-containing space and another portion in communication with the gap to place the gap between the sealing rings in communication with the oil-containing space and which is provided with a closure element in the form of a diaphragm having one of its faces in communication with both duct portions, the duct and element being provided to relieve the pressure in the gap.