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Temperature control system for a cryogenic refrigeration

  • US 5,018,357 A
  • Filed: 03/01/1990
  • Issued: 05/28/1991
  • Est. Priority Date: 10/11/1988
  • Status: Expired due to Fees
First Claim
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1. A cryogenic refrigerator having a displacer within a refrigeration cylinder and a compressor comprising a reciprocating armature within an hermetically sealed housing which alternately compresses and expands to cool a portion of a working fluid flowing through the cylinder to cryogenic temperatures, a linear drive motor with a coil assembly for driving the armature, and a temperature control system comprising:

  • a sensor to detect the temperature of the working fluid and,an analog control circuit that adjusts an amplitude of a reference signal in response to a signal generated by the temperature sensor to vary the displacement of the armature reciprocating at a predetermined frequency such that the temperature of the working fluid is adjustable, the control circuit having a pulse width modulation circuit to convert an input signal to a pulse width modulated drive signal that is applied to the coil.

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