Electronic control of cryogenic refrigerators
AssigneeHelix Technology Corporation
InventorsFred F. Chellis, Samuel J. Moschetto
Life of this patent
Estimating the term…
Abstract
In a cryogenics refrigerator having a piston or piston-like displacer reciprocating in a cylinder, the position of the piston or displacer, the temperature at the cold end of the cylinder and/or a refrigeration gas pressure wave are monitored to provide one or more feedback signals. Valves or a linear motor drive are controlled through electronic control circuitry which responds to the feedback signals. A displacer may be driven by pressure differentials on a drive piston or by an electric motor. The preferred elements provide feedback throughout the refrigeration cycle and include a linear variable displacement transformer and an encoder disc. Preferably, the control circuitry is in the form of a programmable digital processor.
Claims21
A cryogenic refrigerator having a displacer reciprocating in a refrigeration cylinder for displacing refrigeration gas through a regenerator and for expanding and thus cooling the refrigeration gas and gas control valve means for admitting high pressure gas into the refrigeration cylinder and for exhausting the gas from the refrigeration cylinder, the refrigerator comprising:
- means responsive to a physical parameter of the refrigerator for providing an electrical indication of that physical parameter;
- and
- electrically operated timing control means responsive to said electrical indication for controlling the relative timing of the displacer movement and operation of the gas control valve means.
A system comprising a cryogenic refrigerator having a displacer reciprocating in a refrigeration cylinder for expanding and thus cooling a refrigeration gas which flows into and out of the refrigeration cylinder, the system comprising:
- an electronic device cooled by the cryogenic refrigerator;
- and
- electrical timing control means for synchronizing the movement of the displacer and operation of the electronic device so that the electronic device is not operated while the displacer is moving.
Dependencies are inferred from the claim text.