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Browse Prior Art Database

Superconductor Levitated Centrifuge

IP.com Disclosure Number: IPCOM000100958D
Original Publication Date: 1990-Jun-01
Included in the Prior Art Database: 2005-Mar-16
Document File: 2 page(s) / 92K

Publishing Venue

IBM

Related People

Laibowitz, R: AUTHOR [+2]

Abstract

Disclosed is a design for a laboratory centrifuge or ultracentrifuge consisting of a rotating sphere of a cylindrically symmetric magnetic body levitated over a superconducting dish.

This text was extracted from an ASCII text file.
This is the abbreviated version, containing approximately 52% of the total text.

Superconductor Levitated Centrifuge

       Disclosed is a design for a laboratory centrifuge or
ultracentrifuge consisting of a rotating sphere of a cylindrically
symmetric magnetic body levitated over a superconducting dish.

      A common laboratory instrument is a centrifuge which separates
fractions of solid particles in a liquid suspension.  In a
conventional instrument the liquid sample is put into buckets
attached to a vertical axle which is turned by an electric motor.
The centripetal acceleration causes particles of different size or
different density to segregate into horizontal bands.

      This article proposes a new form of this instrument consisting
of a spherical permanent magnet which is levitated in a stable
position above a dish formed from a superconducting material.  The
material to be processed is placed in suitable cavities of the
sphere.  The superconducting material may be one of the recently
discovered high temperature ceramic materials and is cooled either by
contact with liquid nitrogen in a container underneath the
superconducting dish or by a small refrigeration unit.

      The magnetic sphere is then rotated by the action of electrical
currents in a pair of crossed coils of wire which surround the
magnetic sphere as shown in the figure.  The total magnetic field
generated by the two coils will be the vector sum of the two
components and can therefore have any direction in the horizontal
plane.  Coils which carry alternating currents with a 90-degree phase
difference will generate a magnetic field whose direction rotates
around the vertical axis.

      The rotating magnetic field will exert a torque in the sphere
tending to align its moment in the direction of the field.  Proper
control of the phase and frequency of this rotating field will cause
the rotation rate of the sphere to increase or decrease as desired.
Alternatively, there could be conductors imbedded in the sphere in
the manner of the rotor of an induction motor.

      A typical centrifuge subjects the sample to an acceleration of
a few thousand times g,...