CRYOGENIC COOLER FOR A RADIATION DETECTOR, PARTICULARLY IN A SPACECRAFT

Abstract

A cryogenic cooler includes a cold region, a heat-transfer fluid circuit, the cold region being positioned in the circuit, and an application heat exchanger configured to exchange calories with a device to be cooled. The cooler includes at least one passive non-return valve fluidly connected to the cold region, the heat exchanger having at least one first fluid inlet positioned downstream of the non-return valve in the flow direction of the heat-transfer fluid, the heat-transfer fluid circulating from the end of the cold region.

Claims

1. A cryogenic cooler comprising: at least one pressure and flow-rate wave generator, at least one cold finger comprising a cold area, the pressure and flow-rate wave generator being fluidly connected to the cold finger, at least one heat-transfer fluid circuit, at least one application heat-exchanger configured to exchange calories with at least one device to be cooled, wherein the cooler further comprises at least: a first check valve and a second check valve positioned in the circuit, at least one check valve amongst the first and second check valves being a passive check valve, the first check valve and the second check valve being fluidly connected to the cold finger, the at least one application heat-exchanger comprising at least one first fluid inlet positioned downstream of the first check valve in the direction of circulation of the heat-transfer fluid, and at least one first fluid outlet positioned upstream of the second check valve in the direction of circulation of the heat-transfer fluid.

2. The cryogenic cooler according to claim 1, wherein at least one of the check valves comprises one or several Tesla diode(s) in series.

3. The cryogenic cooler according to claim 1, wherein the application heat-exchanger comprises a plurality of inlets associated to a plurality of fluid outlets.

4. The cryogenic cooler according to claim 3, wherein the cold area comprises at least one first heat-exchange area in which the heat-transfer fluid circulates.

5. The cryogenic cooler according to claim 4, wherein the first fluid outlet of the application heat-exchanger is fluidly connected to the first heat-exchange area of the cold area, the first fluid outlet being positioned upstream of the first heat-exchange area of the cold area in the direction of circulation of the heat-transfer fluid.

6. The cryogenic cooler according to claim 5, wherein the second fluid inlet of the application heat-exchanger is fluidly connected to the first heat-exchange area of the cold area, the second fluid inlet being positioned downstream of the first heat-exchange area of the end of the cold area in the direction of circulation of the heat-transfer fluid.

7. The cryogenic cooler according to claim 1, comprising a plurality of application heat-exchangers each comprising at least one heat-transfer fluid inlet and a heat-transfer fluid outlet forming a heat-exchange area.

8. The cryogenic cooler according to claim 1, comprising at least one first buffer tank positioned downstream of the first check valve in the direction of circulation of the heat-transfer fluid, and configured to smooth the pressure and flow-rate wave extracted at the level of the cold area.

9. The cryogenic cooler according to claim 1, comprising at least one second buffer tank positioned upstream of the second check vale in the direction of circulation of the heat-transfer fluid, and configured to smooth the pressure and flow-rate wave arriving at the level of the cold area.

10. The cooler according to claim 8, wherein at least one of the two buffer tanks is constituted by a portion of the heat-transfer fluid circuit.

11. The cooler according to claim 1, wherein said cooler is a pulse-tube or a Stirling cooler.

12. The cooler according to claim 1, wherein the cold finger is in fluidic communication with said heat-transfer fluid circuit.

13. The cooler according to claim 1, wherein the cold finger is not in fluidic communication with said heat-transfer fluid circuit and in that said cooler includes a small pressure and flow-rate wave generator connected to the cold end of the heat-transfer fluid circuit.

14. The cooler according to claim 1, wherein the cold finger is not in fluidic communication with said heat-transfer fluid circuit and in that said cooler includes a T-type direct branch fluidly connecting the pressure and flow-rate wave generator and the cold finger.

15. The cooler according to claim 1, comprising a plurality of application heat-exchangers configured to exchange calories with a plurality of devices to be cooled.

16. A spatial set comprising at least one radiation detector and a cryogenic cooler according to claim 1, the application heat-exchanger of the cooler being configured to cool the radiation detector.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0059] The disclosure will be better understood, thanks to the description hereinafter, which relates to embodiments according to the present disclosure, provided as non-limiting examples and explained with reference to the appended schematic figures. The appended schematic figures are listed hereinbelow:

[0060] FIG. 1 is a schematic view of the cryogenic cooler according to the disclosure according to a first embodiment;

[0061] FIG. 2 is a schematic view of the cryogenic cooler according to the disclosure according to a second embodiment;

[0062] FIG. 3 is a schematic view of the cryogenic cooler according to the disclosure according to a third embodiment;

[0063] FIG. 4 is a schematic view of the cryogenic cooler according to the disclosure according to a fourth embodiment;

[0064] FIG. 5 is a schematic view of the cryogenic cooler according to the disclosure according to a fifth embodiment;

[0065] FIG. 6 is a schematic view of the cryogenic cooler according to the disclosure according to a sixth embodiment; and

[0066] FIG. 7 is a schematic view of the cryogenic cooler according to the disclosure according to a seventh embodiment.

DETAILED DESCRIPTION OF THE DRAWINGS

[0067] The cryogenic cooler 100 according to the disclosure and as illustrated in FIGS. 1 to 5, comprises, regardless of the embodiment, a pressure and flow-rate wave generator 110, a cold finger 120 comprising a cold area 121, a heat-transfer fluid circuit 130, at least one application heat-exchanger 140, 241, 242, configured to exchange calories with a device to be cooled (not represented). Advantageously, the device to be cooled may consist of an electromagnetic or corpuscular radiation detector configured to be integrated to a satellite or to a space probe.

[0068] Regardless of the embodiment, the cryogenic cooler 100 comprises a first check valve 150 and a second check valve 151. The first check valve 150 and the second check valve 151 are positioned on either side of the cold area 121 in the circuit 130.

[0069] In the illustrated examples and regardless of the embodiment of the circuit of the cooler 100, the first and second check valves are passive check valves, for example Tesla diodes. The first check valve 150 and the second check valve 151 are fluidly connected to the cold area 121 by a direct line 131.

[0070] In the embodiments represented in FIGS. 1, 2, 4 and 5, the cold finger 120 comprises a distal cold area 121 of the pressure wave generator 110 and a proximal hot end 122 of the pressure wave generator 110. In the body of the cold finger 120, is arranged a pulse tube 123 around which a regenerator 124 is positioned.

[0071] Furthermore, a transfer line 101 fluidly connects the pressure and flow-rate wave generator 110 to the cold area 120.

[0072] In the embodiment represented in FIG. 3, the cold area 121 is positioned substantially between the regenerator 124 and the pulse tube 123. Hence, the cold area is central.

[0073] According to the second and fifth embodiments, the cold area 121 comprises a first heat-exchange area 125 and a second heat-exchange area 126 in each of which the heat-transfer fluid circulates.

[0074] Advantageously, the cold area 121 comprises a cold area heat-exchange integrating the first 125 and second 126 heat-exchange areas of the cold area 121.

[0075] In FIG. 1, there is represented the cryogenic cooler 100 according to the disclosure comprising a circuit 130 according to a first embodiment. In this first embodiment, the heat-transfer fluid circulates as follows. Starting from a direct line 131 connecting the cold area 121 with the first and second check valves 150, 151, the fluid circulates towards the first check valve 150 which comprises a channel directed in a preferred direction of circulation so that the fluid preferably circulates in this direction. The fluid reaches a first buffer tank 152 configured to smooth the pressure of the fluid within the circuit 130. The heat-transfer fluid is directed towards a first fluid inlet 141 of the application heat-exchanger 140 configured to exchange with the device to be cooled. The fluid comes out of the exchanger 140 through a first outlet 142 and is directed towards a second buffer tank 153 configured to smooth again the pressure of the fluid coming out of the exchanger. Afterwards, the fluid passes through the second check valve 151, which is configured in the same direction of circulation as the first check valve 150.

[0076] In this configuration, the thermal conductance in operation is substantially 0.12 W/K.

[0077] In FIG. 2, there is represented the cryogenic cooler 100 according to the disclosure comprising a circuit 130 according to a second embodiment. In this second embodiment, the heat-transfer fluid circulates as follows. Starting from the direct line 131 connecting the cold area 121 with the first and second check valves 150, 151, the fluid circulates towards the first check valve 150 which comprises a channel directed in a preferred direction of circulation so that the fluid preferably circulates in this direction. The fluid reaches a first buffer tank 152 configured to smooth the pressure of the fluid within the circuit 130. The heat-transfer fluid is directed towards the first fluid inlet 141 of the heat-exchanger 140 configured to exchange with the device to be cooled. The fluid comes out of the exchanger 140 through a first outlet 142 and is directed towards a first heat-exchange area 125 of the cold area 121. Once the first exchange area 125 is crossed, the fluid is directed again towards the exchanger 140 and comes in through the second inlet 143 and comes out through the second outlet 144 and is directed towards a second heat-exchange area 126 of the cold area 121. Once the second exchange area 126 is crossed, the fluid is directed again towards the exchanger 140 and comes in through the third inlet 142 and comes out through the third outlet 146 and is directed towards the second buffer tank 153 configured to smooth the pressure of the fluid coming out of the exchanger 140. Afterwards, the fluid passes through the second check valve 151, which is configured in the same direction of circulation as the first check valve 150.

[0078] In this configuration, the heat-transfer fluid passes three times in the heat-exchanger 140, the thermal conductance in operation is thus increased up to 0.35 W/K, with a start/stop thermal conductance ratio of the cooler of less than 1750.

[0079] Alternatively and in order to improve the performance of the cooler, the heat-transfer fluid could pass six times or more in the heat-exchanger 140. The thermal conductance evolving linearly, it is possible to expect a thermal conductance in operation in the range of 0.72 W/K with a start/stop thermal conductance ratio of the cooler of 1800.

[0080] In FIG. 3, there is represented the cryogenic cooler 100 according to the disclosure comprising a circuit 130 according to a third embodiment. The third embodiment differs from the embodiments illustrated in FIGS. 1,2, 4 and 5 in that it does not comprise a direct line 131 between the first and second check valves 150, 151. The heat-transfer fluid circulates in the entirety of the cold area 121.

[0081] In the fourth embodiment, the heat-transfer fluid circulates from the direct line 131 towards the first check valve 150. The fluid reaches a first buffer tank 152 configured to smooth the pressure of the fluid within the circuit 130. Then, the heat-transfer fluid is directed towards a first fluid inlet 141 of the application heat-exchanger 140 configured to exchange with a first device to be cooled. The fluid comes out of the exchanger 140 through a first outlet 142. The heat-transfer fluid is then directed towards a first fluid inlet 341 of a second application heat-exchanger 241 configured to exchange with a second device to be cooled. The fluid comes out of the exchanger 241 through a first outlet 342. The heat-transfer fluid is then directed towards a first fluid inlet 441 of a third application heat-exchanger 242 configured to exchange with a third device to be cooled. The fluid comes out of the exchanger 242 through a first outlet 442. Finally, the heat-transfer fluid is directed towards a second buffer tank 153 configured to smooth again the pressure of the fluid coming out of the exchanger. Afterwards, the fluid passes through the second check valve 151, which is configured in the same direction of circulation as the first check valve 150.

[0082] In the fifth embodiment, the heat-transfer fluid circulates from the direct line 131 towards the first check valve 150. The fluid reaches a first buffer tank 152 configured to smooth the pressure of the fluid within the circuit 130. Then, the heat-transfer fluid is directed towards a first fluid inlet 141 of the application heat-exchanger 140 configured to exchange with a first device to be cooled. The fluid comes out of the exchanger 140 through a first outlet 142 and is directed towards a first heat-exchange area 125 of the cold area 121. Once the first exchange area 125 is crossed, the fluid is then directed towards a first fluid inlet 341 of a second application heat-exchanger 241 configured to exchange with a second device to be cooled. The fluid comes out of the exchanger 241 through a first outlet 342 and is directed towards a second heat-exchange area 126 of the cold area 121. Once the second exchange area 126 is crossed, the fluid is then directed towards a first fluid inlet 441 of a third application heat-exchanger 242 configured to exchange with a third device to be cooled. The fluid comes out of the exchanger 242 through a first outlet 442. Finally, the heat-transfer fluid is directed towards a second buffer tank 153 configured to smooth again the pressure of the fluid coming out of the exchanger. Afterwards, the fluid passes through the second check valve 151, which is configured in the same direction of circulation as the first check valve 150.

[0083] In the sixth embodiment, schematically represented in FIG. 6, the cryogenic cooler 100 according to the disclosure differs from the previously-described one in that the cold finger 120 is not in fluidic communication with said heat-transfer fluid circuit 130 and in that it includes a small pressure and flow-rate wave generator 110 fluidly connected to the cold end of the heat-transfer fluid circuit 130.

[0084] In the seventh embodiment, schematically represented in FIG. 7, the cryogenic cooler 100 according to the disclosure differs from the previously-described one in that the cold finger 120 is not in fluidic communication with said heat-transfer fluid circuit 130 and in that it includes a T-type direct branch 160 fluidly connecting the pressure and flow-rate wave generator 110 and the cold finger 120. A heating switch is activated as soon as the cooler is turned on.

[0085] It should be noted that this integration is that one which has the least impact on the cooler. Of course, the disclosure is not limited to the embodiments described and represented in the appended figures. Modifications are still possible, in particular with regards to the constitution of the various elements or by substitution with technical equivalents, yet without departing from the scope of the disclosure.