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US 5,667,363 AGranted
Magnetically supported friction pump
AssigneeBalzers-Pfeiffer GmbH
InventorsHelmut Bernhardt, Rene Larsonneur
Life of this patent
Estimating the term…
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.
Claims4
A friction pump, comprising:
- a housing;
- at least one pumping stage for conveying gases, located in said housing and including:
- a rotor;
- a stator surrounding the rotor,
- magnetic means for supporting the rotor and comprising at least one actively controlled magnetic radial bearing for supporting the rotor in a predetermined radial position relative to one of the housing and the stator, and a mechanical emergency bearing for supporting the rotor in case of failure of the magnetic means;
- and
- means for determining a geometrical center of the mechanical emergency bearing and for retaining the rotor in the geometrical center of the emergency bearing, the determining and retaining means comprising:
- means for consecutively displacing the rotor in two mutually perpendicular directions against the emergency bearing;
- radial sensor means for sensing a position of the rotor obtained by displacement of the rotor and for generating a position signal, and
- control means for computing the geometrical center of the emergency bearing and for controlling the magnetic radial bearing so that the predetermined radial position of the rotor corresponds to a position of the rotor in the geometrical center of the emergency bearing.
7 more elements
Dependencies are inferred from the claim text.