Refrigerators

Claim 2

A multilayer low temperature refrigerator comprising a pressure tight bonded laminate of at least three plates of glass or similarly low thermally conductive material, means forming high pressure gas inlet and low pressure gas return passage means in said laminate, said inlet and return passage means being spaced apart by at least one of said plates and extending in counterflow heat exchange relation, said inlet passage means including a capillary section and terminating in a cooling chamber, and means defining a fluid flow passage leading from the cooling chamber to the low pressure return passage means.

Claim 3

The refrigerator defined in claim 1, wherein at least said inlet passage means is of micron dimensions in cross section.

Claim 4

The refrigerator defined in claim 1 wherein said inlet passage means are channels having a width of about 5-500 microns wide and a depth of about 2-500 microns.

Claim 5

A multilayer microminiature refrigerator comprising a laminate of three planar-surfaced thin plates bonded pressure-tight at the interfaces between adjacent plates, means providing in one interface between two adjacent plates a first continuous inflow passage means extending from an inlet to a cooling chamber and including capillary passage means, means for connecting said inlet to a source of refrigerant gas at high pressure, means providing in the other interface between two adjacent plates a further continuous outflow passage menas leading to an outlet, and a passage interconnecting said chamber and said further passage means whereby fluid at reduced pressure from said cooling chamber may pass through said further passage means to said outlet in counterflow heat exchange relation with fluid in said first passage means for regenerative precooling, each of said passage means being of micron size whereby to promote laminar flow therein.

Claim 6

A multilayer microminiature refrigerator comprising a laminate of three planar-surfaced thin plates bonded pressure-tight at the interfaces between adjacent plates, means providing in one interface between two adjacent plates a first continuous inflow passage means extending from an inlet to a cooling chamber and including capillary passage means, means for connecting said inlet to a source of refrigerant gas at high pressure, means providing in the other interface between two adjacent plates a further continuous outflow passage menas leading to an outlet, and a passage interconnecting said chamber and said further passage means whereby fluid at reduced pressure from said cooling chamber may pass through said further passage means to said outlet in counterflow heat exchange relation with fluid in said first passage means for regenerative precooling, each of said passage means being of micron size whereby to promote laminar flow therein.

Claim 7

The refrigerator defined in claim 4, wherein said plates are thin glass plates of uniform thickness.

Claim 8

The refrigerator defined in claim 5, wherein said glass plates are about 0.020 inches thick.

Claim 9

The refrigerator defined in claim 4, wherein at least the plates in which said passage means are formed are of a low thermal conductivity material such as glass.

Claim 10

The refrigerator defined in claim 4, wherein each of said passage means is recessed into a plate surface.

Claim 11

The refrigerator defined in claim 4, wherein said inflow passage means are each about 250 microns wide and about 10 microns deep, said capillary passage means is about 200 microns wide and said about 10 microns deep and outflow passage means is about 15,000 microns wide and about 25 microns deep.

Claim 12

The refrigerator defined in claim 4, wherein said laminate is mounted at one end on a holder having bores therethrough connecting with said inlet and outlet.

Claim 13

The refrigerator defined in claim 10, in combination with an enclosure that is adapted to be connected to a source of vacuum, and means securing said holder within said enclosure so that the refrigerator has cantilever support in said enclosure.

Claim 14

The refrigerator defined in claim 4, wherein said plates are glass and said chamber is a through opening in one of said plates and a pad is bonded over said opening whereby to provide contact with a device to be cooled, said pad being of a material that is of higher thermal conductivity than the plate in which said opening is formed.

Claim 15

The refrigerator defined in claim 12, wherein said pad is of crystalline aluminum oxide, silicon or beryllium oxide.

Claim 16

The refrigerator defined in claim 4, wherein two adjacent plates are glass and the third plate is of a material having an appreciably higher coefficient of thermal conductivity, said first passage means being formed in the interface between said third plate and the glass plate is bonded to it.

Claim 17

A multilayer refrigerator as defined in claim 4, wherein said cooling chamber is substantially centrally located in said laminate and means is provided whereby an electrical device to be cooled may be secured directly on an outer plate substantially directly in line with said cooling chamber, electrical circuit means for said device being formed on the adjacent surface of said outer plate.

Claim 18

The refrigerator defined in claim 4, wherein said first passage means comprises a heat exchange section comprising a series of parallel channels extending in heat exchange relation with said further passage means and said capillary passage means comprises a smaller diameter convoluted section extending from the heat exchange section to said chamber.

Claim 19

A microminiature cryogenic refrigerator for cooling superconductor and like devices comprising a plurality of members having substantially the same coefficient of thermal expansion, means bonding said members together over parallel interface areas to form a laminate and means forming in said laminate a low temperature chamber connected with input and output fluid ports by respective supply and return fluid lines in the form of channels in or on said members at said interface areas, said supply line comprising a first section for conducting incoming highly compressed gas and a serially connected capillary section whereby the high-pressure gas is allowed to expand and reduce in temperature before entering said chamber, means whereby said chamber may be in heat exchange contact with a device to be cooled, and said return line having a section extending substantially coextensively in heat exchange relation adjacent the first section of said supply line but in a different plane in one laminate, the interfaces between said members being sealed pressure-tight except for said surface channels and ports.

Claim 20

A microminiature cryogenic refrigerator for cooling superconductor and like devices comprising a plurality of members having substantially the same coefficient of thermal expansion, means bonding said members together over parallel interface areas to form a laminate and means forming in said laminate a low temperature chamber connected with input and output fluid ports by respective supply and return fluid lines in the form of channels in or on said members at said interface areas, said supply line comprising a first section for conducting incoming highly compressed gas and a serially connected capillary section whereby the high-pressure gas is allowed to expand and reduce in temperature before entering said chamber, means whereby said chamber may be in heat exchange contact with a device to be cooled, and said return line having a section extending substantially coextensively in heat exchange relation adjacent the first section of said supply line but in a different plane in one laminate, the interfaces between said members being sealed pressure-tight except for said surface channels and ports.

Claim 21

The refrigerator defined in claim 17, wherein said members are thin plates of the same size having relatively low coefficient of thermal expansion such as glass.

Claim 22

The refrigerator defined in claim 17, wherein two of said bonded members are glass and adjacent in the laminate, said channels are recessed in surface of said members, and the other member is a plate having higher thermal conductivity.

Claim 23

A microminiature cryogenic refrigerator for cooling superconductors and like devices comprising a plurality of members having substantially the same coefficient of thermal expansion, means bonding said members together over prallel interface areas to form a laminate, means forming a low temperature chamber in said laminate, means forming a fluid supply passage connecting the exterior of said refrigerator to said chamber, said passage including in series a heat exchanger section and a capillary section, return passage means for conducting fluid from said cooling chamber in heat exchange relation with the incoming fluid in said heat exchange section and additional passage means for conducting a portion of said incoming fluid in bypass relation to said cooling chamber and passing said fluid portion to the exterior of said refrigerator in heat exchange relation with the incoming fluid in said heat exchange section.

Claim 24

A microminiature cryogenic refrigerator for cooling superconductors and like devices comprising a plurality of members having substantially the same coefficient of thermal expansion, means bonding said members together over prallel interface areas to form a laminate, means forming a low temperature chamber in said laminate, means forming a fluid supply passage connecting the exterior of said refrigerator to said chamber, said passage including in series a heat exchanger section and a capillary section, return passage means for conducting fluid from said cooling chamber in heat exchange relation with the incoming fluid in said heat exchange section and additional passage means for conducting a portion of said incoming fluid in bypass relation to said cooling chamber and passing said fluid portion to the exterior of said refrigerator in heat exchange relation with the incoming fluid in said heat exchange section.

Claim 25

The refrigerator according to claim 20 wherein said capillary section comprises two capillary passages in series and said additional passage means is connected to said capillary section at a point between said capillary passages.

Claim 26

The refrigerator according to claim 20 wherein said capillary section comprises two capillary passages arranged in parallel and said additional passage means is connected to the downstream end of one of said capillary passages.