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: 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.

Abstract: The invention describes an arrangement for optimum flooding of high speed vacuum pumps. The actuation of the flood valve (6) is controlled by the forces, which, among other things, are exerted upon the rotor by the flooding process. These forces are determined and used to actuate a flood valve controlling entry of the flooding gas. Such forces can be measured in active magnetically supported rotors by masuring the currents in the magnetic bearings (10 and 12). In case of hybrid bearing systems and purely mechanical bearing systems, force measurement is possible indirectly by means of measuring the distance or spacing between the rotor and the stator, or, alternatively, also by means of force sensors.

Abstract: The invention describes a system of magnetic bearings for high speed rotary vacuum pumps, having two radially centering passive magnetic bearings, which originate axially destabilizing forces and thus an unstable point. The axial position is regulated by an electrical solenoid and the operational point of the radial bearing is axially shifted with reference to the unstable point in direction of a high vacuum flange. One of two emergency bearings is located on a high vacuum end and the other is arranged on a fore-vacuum end between the solenoid and the lower passive radial bearing, the rotor, solenoid and position sensor being arranged so as to insure an easy adjustability of the rotor.