Abstract: An apparatus for connecting a vacuum pump stand with an electronic tube and including guide rails along which guide rolls mounted on the stand suction flange are displaced upon movement of the suction flange toward the electronic tube, and pivotal levers connected with the guide rails and supporting roller mounts of rollers for centering the electronic tube neck, with the suction flange including a gasket ring into which the electronic tube exhaust tube, which projects from the tube neck, extends in the upper end position of the suction flange, and with the guide rails having a variable profile such that the levers move, upon the upward displacement of the suction flange, from a position, in which the centering rollers are spaced from the electronic tube neck, into a position in which the centering rollers firmly engage the electronic tube neck, and then back into a position in which the centering rollers are again spaced from the electronic tube neck.

Abstract: A magnetic bearing arrangement for a rotor of a D.C. electric motor, which is rotated due to cooperation of a permanent magnet provided on the rotor and stator coils, and including a magnetic bearing, and at least one additional coil arrangement provided in a region of the permanent magnet at a side of a stator of the electric motor, and in which a voltage is induced by the rotatable permanent magnet means, with the at least one of the amplitudes and at least one of the phases of the relative geometrical position of the at least one additional coil arrangement and the permanent magnet being used as a sensor signal for stabilizing the magnetic bearing.

Abstract: A vacuum pump system for multi-stage gas inlet systems and including a pumping unit formed of a turbomolecular pump and one or several further pumps arranged downstream of the turbomolecular pump and the rotors of which are located on the same shaft as the rotor of the turbomolecular pump, and an additional intermittently operated dry running pump, which discharges against atmospheric pressure.

Abstract: A method of cooling rotor elements of a molecular vacuum pump having stator and rotor elements, a suction flange defining a gas inlet, and a gas outlet spaced from the suction flange, the method including providing additional gas inlet between the suction flange and the gas outlet and admitting through the additional gas inlet a cooling gas having a thermal conductivity larger than that of the compressible gas.

Abstract: A friction pump, which is equipped with at least one actively controlled magnetic radial bearing, wherein, in order to satisfy the extreme requirements necessary through the tight tolerances of pump elements and an emergency bearing, the high rotational speed and the magnetic support, a special control arrangement for the cooperation of rotor, positional sensors and the magnetic bearing control loop so that a safe operation of the pump at extreme requirements is assured in a simple manner without the use of any additional constructional elements.

Abstract: An arrangement for vacuum-tight sealing of electron tubes is provided with a vacuum pipe system which is connected to the electron tube by a tubularly-shaped connecting element. The connecting element is sealed in a vacuum-tight manner by a special thermal seal-off or melt-down unit after the electron tube has been evacuated. The thermal seal-off or melt-down unit is provided with a heating coil which is embraced by a component. The component is provided with an arresting element so that the component can be easily removed from the thermal seal-off or melt-down unit.

Abstract: A friction pump having individual components designed to form simultaneously essential parts of a magnetic bearing assembly for supporting the pump rotor, and essential parts adapted to fulfill essential functions of a friction pump.

Abstract: A venting arrangement for a magnetically supported vacuum pump which has a high speed rotor, wherein the load carrying capacity of the axial magnetic bearing is increased in the course of the venting process by reducing the gap between the axial support disk and the axial magnet in order to carry the additional forces caused by the venting process. In normal operation, the gap is adjusted to an upper limit value.