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Heraeus Instruments Gmbh

Ingo Jaeckel

Frank Werfel

Michael Koch

Dietmar Kopp

Viktor Betke

Uta Fl&ouml;gel-Delor

Ruediger Uhlendorf

A centrifuge with a rotor set-up having at least one magnetic bearing is invented to operate a novel centrifuge. The rotor arrangement is connected with at least one permanent magnet configuration which is radially separated by small gap from a passive superconducting magnet stator. The permanent magnets which are adjusted in such a way that the escaping magnetic flux penetrates the adjacent surface of the passive superconducting magnet stator at a substantially perpendicular orientation. A driving motor unit, preferably in the form of a contactless induction engine, ensures a free and frictionless rotation. The passive superconducting magnet stator is comprised a melt textured superconducting YBCO material of high critical current density which can be cooled below its critical temperature of T&equals;92 K using an integrated cryogenic unit to obtain the superconducting state. The stator has a preferred shape of a cylinder or hollow cylinder.

Centrifuge with a magnetically stabilized rotor for centrifugal goods

In order to determine an imbalance of a rotor caused to turn by means of a driving arrangement, imbalance-produced deflections or accelerations of the driving arrangement, spring-loaded with respect to a stationary housing, are determined and relayed as an electrical signal to an evaluation device. The sensor may be, for example, a piezoelectric crystal for detection of accelerations of the drive unit caused by imbalance or a path sensor for detection of deflections of the drive unit relative to the housing as a result of imbalance. The signal is evaluated as a function of the rotary speed of the rotor by means of an adaptive band filter. The method is especially suitable for determination of imbalance during operation of laboratory centrifuges, where an imbalance can occur, for example, from breakage of test tubes.

Method and device for determining an imbalance and application of the

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Badenhausen, Germany

Ingo Jaeckel