Abstract: A liquid-ring vacuum pump comprises a pump casing and a shaft eccentrically mounted in the pump casing. An impeller and a rotor of a drive motor are connected to the shaft. A disk cam is arranged parallel to the impeller. A first main bearing for the shaft is arranged between the impeller and the rotor of the drive motor, on the plane of the disk cam. The impeller is arranged between the first main bearing and a second main bearing. The arrangement of the bearings prevents the shaft from bending, thus allowing the leakage gap between the impeller and the disk cam to be kept small.

Abstract: A liquid-ring vacuum pump comprises a pump casing and an impeller that is eccentrically mounted in the pump casing. The impeller is made of a material having a modulus of elasticity of less than 4000 N/mm2.

Abstract: The apparatus for monitoring appliances and machines having rotating components, particularly for monitoring compressors, vacuum pumps and other pumps, has a sensor, an evaluation electronics unit and an interface for the output of signals. The evaluation electronics unit has a microprocessor having three inputs for performing measurements in three different frequency ranges at different frequency resolutions, with the respective vibration intensities being averaged at a plurality of frequencies in line with the third-octave spectrum. The interface is a two-wire interface which is used to report different operating states using different DC values.

Abstract: The apparatus for monitoring appliances and machines having rotating components, particularly for monitoring compressors, vacuum pumps and other pumps, has a sensor, an evaluation electronics unit and an interface for the output of signals. The evaluation electronics unit has a microprocessor having three inputs for performing measurements in three different frequency ranges at different frequency resolutions, with the respective vibration intensities being averaged at a plurality of frequencies in line with the third-octave spectrum. The interface is a two-wire interface which is used to report different operating states using different DC values.

Abstract: A displacement machine for compressible media includes at least two shafts. Each of the shafts has a rotor which is configured as a profiled body with the profiles of the rotors engaging one another in the manner of gearwheels during rotation and running without contact relative to one another. Each of the shafts is driven by an electric motor. The angular positions of each shaft is determined by an associated synchro resolver. Each of the synchro resolvers has a rotor and emits an electronic signal to the electric motor of the shaft such that the motors are electronically synchronized. Each of the shafts further has a gearwheel, with the gearwheels engaging one another and having an angular clearance which is smaller than that of the profiled bodies. At least one of the gearwheels is directly connected to the rotor of the synchro resolver associated with its shaft and both gearwheels together are releasably connected as a unit to the shaft.

Abstract: A displacement machine for compressible media has at least two shafts with rotors which are designed as helical profile bodies. During rotation, the profiles intermesh like gears and run free of contact relative to one another. The lead of the helical profile bodies decreases from the inlet end to the outlet end and have a double-start design, with the leads at the inlet end and outlet end of the helical profile bodies being constant, and the intermediate lead decreasing continuously from the larger lead at the inlet end to the smaller lead at the outlet end.

Abstract: The rotary piston machine with an axial direction of delivery from the top downwards, in particular of screw spindle-type construction, with cooling ducts (12) for the motors (8), bearings (7) and sensors (9), through which ducts a cooling fluid flows, and with a cooling device for the pump space (3) is characterized in that the casing (2) of the pump space (3) has a closed annular space (15) which is partially filled with a liquid, which is cooled by the cooling fluid via heat exchanger surfaces (18).

Abstract: Screw-spindle vacuum pump with at least three closed-off feed chambers located one behind the other along each rotor and method for operating this compressor. The chamber which is last on the delivery side is brought virtually to the compression limit pressure by means of pre-admission, shortly before it opens towards the delivery side, by supplying a pre-admission stream which is at least five times as great as the intake mass stream. A precondition, in this case, is a minimum ratio of external compression to internal compression of five.