IDCA for fast cooldown and extended operating time

Patent metadata

Field	Value
Publication number	US-9328943-B2
Application number	US-201213822522-A
Country	US
Kind code	B2
Filing date	Jul 20, 2012
Priority date	Jul 22, 2011
Publication date	May 3, 2016
Grant date	May 3, 2016

Abstract

Systems, methods, and devices for integrated detector cooler assemblies (IDCAs) and multi-circuit cryostats are discussed herein. Solutions include using cryostats with multiple cooling circuits. Some cryostat variations may include a rapid cooldown circuit and a temperature maintenance circuit. In some cases, the temperature maintenance circuit may be a closed-loop circuit run by a compressor instead of an open-loop circuit run on a pressurized gas bottle/cartridge. Variations of a cryostat may also include a gas expander portion that replaces the coldfinger of typical IDCAs. Further variations of cooling circuits may include circuits that perform reverse-flow heat exchange to pre-cool incoming refrigerant and also cooling circuits that have heat bridges disposed thereon to assist in such heat exchange.

First claim

What is claimed is:

1. An integrated detector cooler assembly (IDCA) comprising:
a planar, circular disk-shaped Joule-Thomson cryostat in direct contact with a focal plane array (HA), the cryostat comprising:
a disk center portion in a middle of the cryostat, the disk center portion having a first center half and a second center half;
a first disk half portion including the first center half;
a second disk half portion including the second center half;
a first cooling circuit disposed on the first disk half portion and comprising a first gas expander portion in the first center half; and
a second cooling circuit disposed on the second disk half portion and comprising a second gas expander portion in the second center half; and

a first refrigerant source having a mixed-gas refrigerant to be provided to at least one of said cooling circuits;
wherein at least one of the first and second cooling circuits is configured to operate as a reverse-flow heat exchanger, such that entering refrigerant is cooled by exiting refrigerant;
wherein at least one cooling circuit includes heat-transfer bridges disposed on the cryostat along said cooling circuit to transfer heat between high-pressure and low-pressure portions of the cooling circuit, where the high-pressure portion of the cooling circuit is associated with refrigerant flowing into the circuit and the low-pressure portion of the cooling circuit is associated with refrigerant flowing out of the circuit; and
wherein the first and second cooling circuits are both equipped with said heat transfer bridges, and the first and second gas expander portions being coldest portions of the cryostat and in direct thermal contact with the FPA a control portion configured to operate the first cooling circuit in a first mode and operate the second cooling circuit in a second mode.

2. The IDCA of claim 1 , the IDCA further comprising a compressor; and
where the first refrigerant source provides refrigerant to the first cooling circuit, said first cooling circuit being configured for open-loop operation; and
where the compressor provides refrigerant to the second cooling circuit, said second cooling circuit being configured for closed-loop operation.

3. The IDCA of claim 1 , the IDCA further comprising a second refrigerant source; and
wherein the first refrigerant source provides refrigerant to the first cooling circuit, said first cooling circuit being configured for open-loop operation; and
wherein the second refrigerant source provides refrigerant to the second cooling circuit, said second cooling circuit being configured for open-loop operation.

4. The IDCA of claim 1 , the IDCA further comprising a control portion; and
wherein the control portion controls operation of the first and second circuits by activating the first circuit to bring the FPA disposed on the cryostat to a desired operating temperature and by activating the second circuit to maintain the FPA at the desired operating temperature.

5. The IDCA of claim 1 , the IDCA further comprising a switching portion that controls a flow of refrigerant from the first refrigerant source to at least one of the cooling circuits.

6. The IDCA of claim 1 , the IDCA further comprising:
a first switching portion that controls a flow of refrigerant from the first refrigerant source to the first cooling circuit; and
a second switching portion that controls a flow of refrigerant to the second cooling circuit.

7. The IDCA of claim 1 , wherein the first and second cooling circuits are both equipped with said heat transfer bridges.

8. The IDCA of claim 1 , wherein the mixed-gas refrigerant includes one or more of ethane, methane, or isobutane.

9. The IDCA of claim 1 , wherein the first refrigerant source supplies the refrigerant used to operate the second cooling circuit.

10. The IDCA of claim 9 , wherein the refrigerant used to operate the second cooling circuit is recovered from a refrigerant exhaust of the first cooling circuit.

11. The IDCA of claim 1 , wherein:
the first center half includes baffles to take high-pressure refrigerant for expansion; and
the second center half includes baffles to take high-pressure refrigerant for expansion, wherein the expansion to cause a local low-pressure area at the center portion.

12. The IDCA of claim 1 , wherein the first cooling mode is a high-flow, rapid cooling mode and the second cooling mode is a low-flow, temperature maintenance mode.

13. A cryostat, the cryostat comprising:
planar disk-shaped structure including a center portion having a first center half and a second center half in a middle of the structure; a first half-circular portion including the first center half; and a second half-circular portion including the second center half;
a first Joule-Thomson (JT) cooling circuit disposed on the first half-circular portion and comprising a first gas expander portion in the first center half;
a second JT cooling circuit disposed on the second half-circular portion and comprising a second gas expander portion in the second center half;
a mixed-gas refrigerant flowing in said first and second cooling circuits;
the first and second JT cooling circuits configured to operate as reverse-flow heat exchangers such that the refrigerant entering the cooling circuits via a refrigerant inlet port is cooled by refrigerant leaving the circuits via a refrigerant outlet port;
heat transfer bridges disposed on said cryostat along at least one of said first and second JT cooling circuits, said heat transfer bridges being configured to enhance the reverse-flow heat exchange operation of the at least one of said first and second cooling circuits; and
the first and second gas expander portions being coldest portions of the cryostat and in direct thermal contact with a photodetector a control portion configured to operate the first JT cooling circuit in a first mode and operate the second cooling JT circuit in a second mode.

14. The cryostat of claim 13 , wherein the photodetector is a high operating temperature (HOT) infra-red (IR) photodetector disposed on the cryostat.

15. The cryostat of claim 13 , wherein the heat transfer bridges have a coefficient of thermal expansion (CTE) that matches the CTE of the cryostat.

16. The cryostat of claim 13 , wherein the cryostat is formed from two glass plates, an upper plate and a lower plate, wherein the first and second JT cooling circuits are etched into the lower plate, wherein the upper plate includes heat transfer bridge pockets to accommodate said heat transfer bridges therein, and wherein the upper and lower plates are bonded together to form the cryostat.

17. The cryostat of claim 13 , wherein:
the first center half includes baffles to take high-pressure refrigerant for expansion; and
the second center half includes baffles to take high-pressure refrigerant for expansion, wherein the expansion to cause a local low-pressure area at the center portion wherein the first half-circular portion is separate from the second half-circular portion and side-by-side.

18. The cryostat of claim 13 , wherein the first cooling mode is a high-flow, rapid cooling mode and the second cooling mode is a low-flow, temperature maintenance mode.

19. A method of cooling a focal plane array (FPA) disposed in an integrated detector cooler assembly (IDCA) to an operating temperature, the method comprising:
providing a Joule-Thomson (JT) cryostat in the IDCA, the JT cryostat having a planar disk-shaped structure including a center portion having a first center half and a second center

Assignees

• Loung Vincent
• Saito Elna
• Scott Jeff W
• Lockheed Corp

Inventors

• Loung Vincent
• Saito Elna
• Scott Jeff W

Classifications

• F25B9/02 Primary

  using Joule-Thompson effect; using vortex effect · CPC title

• F25B19/02 Primary

  using fluid jet, e.g. of steam {(F25B19/005 takes precedence)} · CPC title

• F25B39/02

  Evaporators · CPC title

• H05K7/20254

  Cold plates transferring heat from heat source to coolant · CPC title

• H05K7/20354

  Refrigerating circuit comprising a compressor · CPC title