GB1401514A - Magnetic suspension apparatus - Google Patents

Abstract

1401514 Suspending centrifuge rotors CAMBRIDGE THERMIONIC CORP 7 July 1972 [7 July 1971] 31877/72 Heading B2P [Also in Divisions F2, G3 and H2] In magnetic suspension apparatus in which a movable body 11 is suspended in a desired position by permanent magnets 26, 27 located at opposite ends of the body, the body is controlled by electromagnets which produce restoring forces to counteract any perturbations applied to the body and which move the body to a position wherein the net force produced by the permanent magnets counteracts a constant force such as gravity. The magnets 26, 27 are associated with stationary permanent magnets 14, 15. The apparatus includes two electromagnets 12, 13, differentially energised by an amplifier 29, when necessary, to restore the body 11 to its equilibrium position, in response to control signals from a position sensor and a velocity sensor. The electromagnet 12, 13 and amplifier 29 are associated with biasing circuits. The position sensor comprises a light source 34, photo-electric cells 36 and a shield 35 mounted on the end of the movable body. The velocity sensor comprises a coil 32 associated with magnet 27. In a modification, Fig 2 (not shown), the magnet 27 is disposed axially outside the associated stationary magnet (60). In a further modification, Fig 3 (not shown), one of the stationary permanent magnets and one of the electromagnets form a combined unit. The body 11 may support a centrifuge rotor and may be rotated by stator 16.