US 4,389,849 A · Stirling cycle cryogenic cooler

Abstract

A long lifetime Stirling cycle cryogenic cooler particularly adapted for space applications comprised of a compressor section (10) centrally aligned end to end with an expansion section (12) and respectively including a reciprocating compressor piston (14) and displacer (16) radially suspended in interconnecting cylindrical housings (18, 20) by active magnetic bearings (26, 28, 30, 32) and having adjacent reduced clearance regions (82, 84, 108) so as to be in non-contacting relationship therewith and wherein one or more of these regions operate as clearance seals. The piston (14) and displacer (16) are reciprocated in their housings (18, 20) by linear drive motors (48, 52) to vary the volume of respectively adjacent compression and expansion spaces (44, 46) which contain a gaseous working fluid and a thermal regenerator (95) to effect Stirling cycle cryogenic cooling. Electrical circuit means (140, 142) are additionally included for energizing the magnetic bearings (26, 28, 30, 32) and for controlling the stroke amplitudes and relative phase angle between the compressor piston (14) and displacer (16) during the cooling cycle.

Claims30

Dependent claims

Apparatus comprising in combination:

a reciprocally movable body (14, 16) located in a body housing (18, 20) containing a working fluid;
drive motor means (48, 52) coupled to said body (14, 16) for effecting reciprocation of said body (14, 16) within said housing (18, 20) to selectivety compress and expand said working fluid;
non-contacting bearing means (26, 28, 30, 32) on said housing (18, 20) and being operable to center said body (14, 16) in said housing;
a non-contacting reduced clearance region (82, 84, 108) between said body and housing for restricting undesired flow of said working fluid around said body (14, 16);
said non-contacting bearing means (26, 28, 30, 32) and said non-contacting reduced clearance region (82, 84, 108) being operable to eliminate physical contact between said body (14, 16) and said housing (18, 20).

2 more elements

Cooling apparatus, comprising in combination:

a reciprocally operable compressor piston (14) located in a generally cylindrical compressor section housing (18) and including a working fluid compression space (44) at one end thereof, said compression space being variable in accordance with the position of the piston in said housing;
a reciprocally operable displacer (16) located in a generally cylindrical expansion section housing (20) and including a working fluid expansion space (46) at one end thereof, said expansion space being variable in accordance with the position of said displacer;
said housings (18, 20) being interconnected and including a working fluid and having means (95, 98, 100, 101, 102, 103, 104, 105, 106) for the flow of working fluid between said compression space (44) and said expansion space (46);
drive motor means (48, 52) coupled to said compressor piston (14) and said displacer (16) and being operable to provide mutual reciprocation of said piston and said displacer in a controlled phase relationship to effect a predetermined cooling cycle by the compression and expansion of said working fluid;
non-contacting bearing means (26, 28, 30, 32) located on said housings (18, 20) and being operable to radially center said piston (14) and said displacer (16) in their respective said housings;
and
non-contacting seal means (84, 108) for restricting undesired flow of said working fluid around said piston (14) and said displacer (16);
said non-contacting bearing means and said non-contacting seal means being operable to eliminate physical contact between said piston (14) and its respective housing (18) and said displacer (16) and its respective housing (20), thereby providing long operational life and non-contamination of the working fluid.

5 more elements

Dependencies are inferred from the claim text.

Stirling cycle cryogenic cooler

Life of this patent

Stirling cycle cryogenic cooler

Life of this patent

Abstract

Claims30