Combined thermal switch and refrigerator

Abstract

The invention relates to the technical field of refrigeration and low temperature, and provides a combined type thermal switch and a refrigerator, the combined type thermal switch comprises a thermal switch body and a plurality of superconductive layers, and the thermal switch body is provided with a hot end and a cold end which are oppositely arranged; the first superconducting layer is arranged on the end face of the hot end and tightly attached to the end face of the hot end. The second superconducting layer is arranged on the side, away from the hot end, of the first superconducting layer, and the first superconducting layer and the second superconducting layer are arranged in a stacked mode; wherein the superconducting transition temperature of the first superconducting layer is lower than that of the second superconducting layer. According to the refrigerator, heat leakage generated when the heat switch is switched off is reduced, the refrigerating capacity of the refrigerator is greatly reduced, the refrigerator can obtain the lower refrigerating temperature, and the refrigerating capacity is also improved at the same temperature.

Description

Technical Field

[0001] The present invention relates to the field of refrigeration and cryogenic technology, and in particular to a combined thermal switch and a refrigerator. Background Art

[0002] A dilution refrigerator is a commercial refrigerator that can stably provide extremely low temperatures below 10mK. It is a major component of quantum computers and is also widely used in quantum research. The currently commonly used dry dilution refrigerator mainly relies on 4K pulse tube refrigerators for pre-cooling, and the thermal switch is its key component. During pre-cooling, from room temperature 300K to 4K liquid helium temperature, the thermal switch needs to be kept on to accelerate the cooling, and when the liquid helium temperature is reached, it needs to be disconnected to reduce the heat leakage of the thermal switch. In addition to dilution refrigerators, thermal switches are also widely used in extremely low temperature systems such as adiabatic demagnetization refrigerators and 1K refrigerators.

[0003] Thermal switches are mainly divided into air-gap thermal switches, superconducting thermal switches, mechanical thermal switches, etc. according to their working principles. Taking the air-gap thermal switch as an example, the air-gap thermal switch is connected by filling the copper conductors at the upper and lower ends with a heat-conducting gas, usually helium-4 and helium-3, and gas heat transfer. There is also a small chamber at the upper end, which is filled with porous materials such as activated carbon. Since the adsorption capacity of activated carbon increases greatly with the decrease of temperature, the activated carbon can adsorb helium at low temperatures, so that a good vacuum is maintained between the conductors. At this time, the thermal conductivity of the thermal switch is greatly reduced, and the thermal switch is disconnected. If the thermal switch is disconnected prematurely, or if the thermal switch needs to be turned on again, the adsorbed helium can be released again by heating the activated carbon to achieve gas heat conduction again.

[0004] However, activated carbon cannot completely absorb all the helium. Some residual gas will continue to conduct heat. When the disconnection temperature is too low, some helium will be liquefied and remain in the bottom chamber. When the liquid helium reaches the superfluid temperature, superfluid film climbing will occur, further enhancing the heat conduction. The cooling capacity of the dilution refrigerator is very small, generally in the milliwatt or even microwatt level. A little residual heat leakage will cause the refrigerator to fail to reach the desired temperature, so it is particularly important to further solve these residual heat leakage. Summary of the invention

[0005] The present invention provides a combined thermal switch and refrigerator, which are used to solve the defects of the traditional thermal switch in the prior art that there is a certain amount of residual heat leakage and incomplete disconnection, and achieves the reduction of heat leakage of the thermal switch when it is disconnected, greatly saving the limited cooling capacity of the refrigerator, so that the refrigerator can obtain a lower cooling temperature, and the cooling capacity at the same temperature is also improved.

[0006] The present invention provides a combined thermal switch, comprising: A thermal switch body, wherein the thermal switch body has a hot end and a cold end that are arranged opposite to each other; A first superconducting layer, wherein the first superconducting layer is disposed on an end surface of the hot end and is closely disposed with the end surface of the hot end; a second superconducting layer, the second superconducting layer being arranged on a side of the first superconducting layer away from the hot end, the first superconducting layer and the second superconducting layer being arranged in a stacked manner; Wherein, the superconducting transition temperature of the first superconducting layer is lower than the superconducting transition temperature of the second superconducting layer.

[0007] According to a combined thermal switch provided by the present invention, the first superconducting layer is an indium sheet.

[0008] According to a combined thermal switch provided by the present invention, the combined thermal switch comprises a plurality of the first superconducting layers, wherein the plurality of the first superconducting layers are stacked and arranged between the second superconducting layer and an end surface of the hot end.

[0009] According to a combined thermal switch provided by the present invention, the second superconducting layer is an aluminum oxide gasket.

[0010] According to a combined thermal switch provided by the present invention, the radius of the cross section of the first superconducting layer is greater than or equal to the radius of the end face of the hot end.

[0011] According to a combined thermal switch provided by the present invention, the radius of the cross section of the second superconducting layer is greater than or equal to the radius of the end face of the hot end.

[0012] According to a combined thermal switch provided by the present invention, the thickness of the first superconducting layer along the axial direction is smaller than the thickness of the second superconducting layer along the axial direction.

[0013] According to a combined thermal switch provided by the present invention, the first superconducting layer is arranged in a ring shape; And / or, the second superconducting layer is arranged in a ring shape.

[0014] According to a combined thermal switch provided by the present invention, the thermal switch body includes any one of an air gap thermal switch and a convection thermal switch.

[0015] The present invention also provides a refrigerator, comprising any one of the combined thermal switches described above.

[0016] The combined thermal switch and refrigerator provided by the present invention are provided with a first superconducting layer and a second superconducting layer at the hot end of the thermal switch body, wherein the superconducting transition temperature of the first superconducting layer is lower than the superconducting transition temperature of the second superconducting layer, and the first superconducting layer and the second superconducting layer have good thermal conductivity at a high temperature, which can further enhance the thermal conductivity effect of the thermal switch. When the temperature drops below the superconducting transition temperature of the second superconducting layer, the second superconducting layer gradually changes to a superconducting state, and the thermal conductivity gradually decreases. As the temperature further decreases, the second superconducting layer enters deep superconductivity, and the thermal conductivity becomes very small. When the temperature of the hot end of the thermal switch reaches the superconducting transition temperature of the first superconducting layer, the first superconducting layer changes to a superconducting state, and the thermal conductivity decreases sharply, thereby disconnecting the thermal switch body. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0018] Figure 1 It is a structural schematic diagram of the combined thermal switch provided by the present invention.

[0019] Figure 2 It is a schematic structural diagram of the first superconducting layer provided by the present invention.

[0020] Figure 3 It is a schematic diagram of the structure of the second superconducting layer provided by the present invention.

[0021] Reference numerals: 10. Combined thermal switch; 100, thermal switch body; 110, cold end; 120, hot end; 200, a first superconducting layer; 300. Second superconducting layer. DETAILED DESCRIPTION

[0022] The following is a further detailed description of the embodiments of the present invention in conjunction with the accompanying drawings and examples. The following examples are used to illustrate the present invention but are not intended to limit the scope of the present invention.

[0023] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0024] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0025] In the embodiments of the present invention, unless otherwise clearly specified and limited, the first feature being "above" or "below" the second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, the first feature being "above", "above" and "above" the second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. The first feature being "below", "below" and "below" the second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0026] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the embodiments of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more layers of the embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, without contradiction.

[0027] Combine the following Figures 1 to 3 , the combined thermal switch and refrigerator provided by the embodiment of the present invention are described in detail through specific embodiments and their application scenarios.

[0028] In the embodiment of the present invention, Figure 1 As shown, the combined thermal switch 10 includes a thermal switch body 100 and a plurality of superconducting layers, wherein the thermal switch body 100 has a hot end 120 and a cold end 110 that are arranged opposite to each other; the first superconducting layer 200 is arranged on the end surface of the hot end 120 and is closely arranged with the end surface of the hot end 120; the second superconducting layer 300 is arranged on a side of the first superconducting layer 200 away from the hot end 120, and the first superconducting layer 200 and the second superconducting layer 300 are arranged in a stacked manner; wherein the superconducting transition temperature of the first superconducting layer 200 is lower than the superconducting transition temperature of the second superconducting layer 300.

[0029] The heat switch body 100 is the main structure of the combined heat switch 10, and has a hot end 120 and a cold end 110 that are arranged opposite to each other. The heat switch body 100 serves as a heat transfer path, and its hot end 120 and cold end 110 are connected to the high temperature area and the low temperature area respectively. By controlling the conduction and disconnection of the heat switch, the heat transfer and isolation are realized, thereby achieving the purpose of adjusting the temperature.

[0030] The first superconducting layer 200 is disposed on the end surface of the hot end 120 and is closely disposed with the end surface of the hot end 120. The first superconducting layer 200 is made of a superconducting material with a low superconducting transition temperature.

[0031] The second superconducting layer 300 is disposed on a side of the first superconducting layer 200 away from the hot end 120, and is stacked with the first superconducting layer 200. The second superconducting layer 300 is made of a superconducting material with a relatively high superconducting transition temperature.

[0032] When the temperature is high, the first superconducting layer 200 is in a normal state and has good thermal conductivity, which can enhance the thermal conductivity of the thermal switch, so that heat can be smoothly transferred from the hot end 120 to the cold end 110 .

[0033] When the temperature drops below the superconducting transition temperature of the second superconducting layer 300, the second superconducting layer 300 gradually enters a superconducting state. As the temperature further drops, the second superconducting layer 300 enters a deep superconducting state, and its thermal conductivity becomes very small. At this time, the second superconducting layer 300 plays an isolating role, greatly weakening the transfer of heat, and realizing partial disconnection of the thermal switch.

[0034] When the temperature continues to drop below the superconducting transition temperature of the first superconducting layer 200, the first superconducting layer 200 also enters a superconducting state, and its thermal conductivity decreases sharply. At this time, the second superconducting layer 300 further enhances the isolation effect of the thermal switch, and realizes the complete disconnection of the thermal switch.

[0035] The provision of the first superconducting layer 200 enables the thermal switch to have a lower heat leakage rate when it is disconnected, thereby improving the stability and reliability of the thermal switch.

[0036] The superconducting transition temperature of the first superconducting layer 200 is lower than the superconducting transition temperature of the second superconducting layer 300. Due to the different superconducting transition temperatures of the first superconducting layer 200 and the second superconducting layer 300, the thermal switch exhibits a staged characteristic when disconnecting. First, when the temperature drops below the superconducting transition temperature of the second superconducting layer 300, the thermal switch is partially disconnected; then, when the temperature continues to drop below the superconducting transition temperature of the first superconducting layer 200, the thermal switch is completely disconnected. This staged disconnection characteristic makes the thermal switch have better controllability and stability during the disconnection process.

[0037] By adjusting the superconducting transition temperatures of the first superconducting layer 200 and the second superconducting layer 300 , the thermal switch can be adapted to different temperature requirements.

[0038] The present application adds a first superconducting layer 200 and a second superconducting layer 300 to the hot end 120 of the thermal switch body 100, wherein the superconducting transition temperature of the first superconducting layer 200 is lower than the superconducting transition temperature of the second superconducting layer 300, and the first superconducting layer 200 and the second superconducting layer 300 have good thermal conductivity at a high temperature, which can further enhance the thermal conductivity effect of the thermal switch. When the temperature drops below the superconducting transition temperature of the second superconducting layer 300, the second superconducting layer 300 gradually changes to a superconducting state, and the thermal conductivity gradually decreases. As the temperature further decreases, the second superconducting layer 300 enters deep superconductivity, and the thermal conductivity becomes very small. When the temperature of the hot end 120 of the thermal switch reaches the superconducting transition temperature of the first superconducting layer 200, the first superconducting layer 200 changes to a superconducting state, and the thermal conductivity decreases sharply, thereby disconnecting the thermal switch body 100.

[0039] In some embodiments, the first superconducting layer 200 is an indium sheet.

[0040] It is understood that the indium sheet has very good ductility and can be easily processed into the required shape and size to adapt to the design requirements of the thermal switch body 100. This ductility can also closely fit the surface of the hot end 120 of the thermal switch body 100 to ensure the maximum contact area between the two.

[0041] At room temperature or relatively high temperature, indium sheets have high thermal conductivity. This allows the indium sheets to conduct heat effectively when the thermal switch needs to conduct heat, thereby accelerating the pre-cooling process of the refrigerator.

[0042] The superconducting transition temperature of the indium sheet is relatively high (about 3.4K). When the temperature of the hot end 120 of the thermal switch drops to this temperature, the indium sheet will transform into a superconducting state. In the superconducting state, the thermal conductivity of the indium sheet will drop sharply, which helps to quickly reduce the heat leakage of the thermal switch after precooling is completed and realize the disconnection of the thermal switch.

[0043] Since the indium sheet hardly conducts heat in the superconducting state, in an extremely low temperature environment, using the indium sheet as the first superconducting layer 200 can significantly reduce the residual heat leakage of the thermal switch when it is in the off state.

[0044] The superconducting transition temperature of the indium sheet provides a natural temperature control point, allowing the thermal switch to automatically switch between the on and off states without the need for an external control mechanism.

[0045] In some embodiments, the combined thermal switch 10 includes multiple layers of the first superconducting layer 200 , and the multiple layers of the first superconducting layer 200 are stacked and disposed between the second superconducting layer 300 and the end surface of the hot end 120 .

[0046] It is understandable that when the thermal conductivity of one layer of the first superconducting layer 200 and the second superconducting layer 300 is not low enough, two or even multiple layers of the first superconducting layer 200 and the second superconducting layer 300 can be used so that the thermal switch body 100 has a sufficiently low heat leakage rate when disconnected.

[0047] In some embodiments, the second superconducting layer 300 is an aluminum oxide spacer.

[0048] It is understandable that the superconducting transition temperature of aluminum oxide is about 15K, which is higher than the first superconducting layer 200 (such as indium sheet, the superconducting transition temperature is about 3.4K). In this way, through the staged disconnection mechanism, the thermal switch is gradually disconnected in different temperature ranges. First, when the temperature drops to close to the superconducting transition temperature of aluminum oxide, aluminum oxide begins to transform into a superconducting state, and initially achieves partial disconnection; then, as the temperature further drops below the superconducting transition temperature of the indium sheet, the latter also enters the superconducting state, further enhancing the thermal isolation effect. By controlling the heat conduction path in stages, it is possible to better adapt to the different needs of the system from pre-cooling to stable operation, and improve the efficiency and performance of the entire refrigerator.

[0049] Of course, in other embodiments, the alumina gasket can be replaced with other superconducting materials. Different superconducting materials can be selected to achieve better disconnection of the thermal switch according to the disconnection temperature required by each system.

[0050] The present invention introduces a combined structure of multi-layer indium sheets and aluminum oxide gaskets on the basis of the traditional thermal switch, so that the thermal switch still has a high thermal conductivity when it is turned on, and the conduction effect is good. The key is that when the temperature reaches the pre-cooling temperature and the thermal switch needs to be disconnected, due to the superconducting properties of indium and aluminum oxide, superconductors are poor conductors of heat, especially when the material is deeply superconducting, it will hardly transfer heat, so the combined thermal switch has extremely low thermal conductivity at this time.

[0051] The ratio of the thermal conductivity of the thermal switch when it is on to the thermal conductivity when it is off is called the on-off ratio. The on-off ratio is an important parameter for measuring switch performance. The larger the better. The present invention greatly increases the on-off ratio of the combined thermal switch 10 by reducing the heat leakage when the thermal switch is off, thereby reducing the thermal conductivity when it is off.

[0052] The present invention greatly saves the limited refrigeration capacity of the refrigerator by reducing the heat leakage when the thermal switch is disconnected, so that the refrigerator can obtain a lower refrigeration temperature, and the refrigeration capacity at the same temperature is also improved, which significantly improves the deficiencies in the prior art.

[0053] Reference Figure 1 , the radius of the cross section of the first superconducting layer 200 is greater than or equal to the radius of the end surface of the hot end 120.

[0054] It can be understood that by making the radius of the cross section of the first superconducting layer 200 greater than or equal to the radius of the end face of the hot end 120, that is, fully covering the end face of the hot end 120, it is possible to ensure that there is a maximum contact area between the two, ensuring that heat can be quickly transferred from the hot end 120 through the first superconducting layer 200, thereby maximizing the heat conduction efficiency. At the same time, it is also possible to reduce the radiation heat exchange of the hot end 120, further reducing the generation of heat leakage.

[0055] Reference Figure 1 , the radius of the cross section of the second superconducting layer 300 is greater than or equal to the radius of the end surface of the hot end 120.

[0056] It is understandable that the cross-sectional radius of the second superconducting layer 300 is greater than or equal to the radius of the end face of the hot end 120, ensuring the maximum contact area between it and the first superconducting layer 200. In the pre-cooling stage, it is ensured that heat can be quickly transferred to the second superconducting layer 300 through the first superconducting layer 200, and finally transferred out, maximizing the heat conduction efficiency. In addition, the larger contact area reduces the thermal resistance, allowing the heat to be more evenly distributed and transferred, avoiding the problem of local overheating or uneven cooling. At the same time, it can also reduce the radiation heat exchange of the hot end 120, further reducing the generation of heat leakage.

[0057] Reference Figures 1 to 3 , the thickness of the first superconducting layer 200 along the axial direction is less than the thickness of the second superconducting layer 300 along the axial direction.

[0058] It is understandable that by designing the thickness of the first superconducting layer 200 to be smaller than that of the second superconducting layer 300, a temperature gradient can be created in the thermal switch. When the temperature drops, the thicker second superconducting layer 300 gradually changes to a superconducting state, reducing the heat flow and achieving the initial disconnection of the thermal switch; since the first superconducting layer 200 is thinner, it quickly changes to a superconducting state when it reaches the superconducting transition temperature, so as to achieve a complete disconnection of the thermal switch.

[0059] Reference Figure 2 and Figure 3 , the first superconducting layer 200 is arranged in a ring shape; the second superconducting layer 300 is arranged in a ring shape.

[0060] It can be understood that the first superconducting layer 200 and the second superconducting layer 300 arranged in an annular shape can provide a uniform heat conduction path. That is, the heat can be evenly distributed along the annular path, avoiding local hot spots and improving the overall heat conduction efficiency of the thermal switch. At the same time, the annular structure helps to disperse the thermal stress caused by temperature changes and reduce the stress concentration caused by thermal expansion and contraction of the material, thereby improving the mechanical stability and life of the thermal switch. Moreover, when the annular superconducting layers enter the superconducting state, they can form a continuous thermal insulation barrier, effectively blocking the heat flow, thereby providing a better thermal isolation effect when the thermal switch is disconnected.

[0061] In some embodiments, the thermal switch body 100 includes any one of an air gap thermal switch and a convection thermal switch.

[0062] Of course, in other embodiments, the thermal switch body 100 may also be other forms of thermal switches, which are not particularly limited herein.

[0063] The present invention also provides a refrigerator, which includes the above-mentioned combined thermal switch 10. The specific structure of the combined thermal switch 10 refers to the above-mentioned embodiment; it can be understood that since the above-mentioned combined thermal switch 10 is used in the refrigerator, the embodiment of the refrigerator includes all technical solutions of all embodiments of the above-mentioned combined thermal switch 10, and the technical effects achieved are also exactly the same, which will not be repeated here.

[0064] In a specific embodiment, in the example of a domestically produced dilution refrigerator, a traditional air gap thermal switch was initially used. Since the traditional thermal switch could not be completely disconnected, there was a great deal of heat leakage, which kept the temperature of our evaporation chamber above 1.2K, much higher than the normal temperature. A layer of indium sheet and a layer of alumina gasket were added to the bottom of the traditional thermal switch to form the new combined thermal switch 10 of the present invention. While keeping the other parameters unchanged, the temperature of the evaporation chamber dropped below 1K, indicating that the heat leakage was greatly reduced. Subsequently, a combination of two layers of indium sheet and alumina gasket was used, and the temperature of the evaporation chamber was further reduced to 600mK, meeting the use requirements.

[0065] In a specific embodiment, in the example of a domestically produced 1K refrigerator, a traditional air gap thermal switch was used at the beginning. Since the traditional thermal switch could not be completely disconnected, there was a great deal of heat leakage, which made it impossible for the system to liquefy helium-4 gas normally. Since a stable helium liquid surface was not formed, the temperature of the 1K disk could only drop to more than 2K, far from the target. A layer of indium sheet and a layer of aluminum oxide gasket were added to the bottom of the traditional thermal switch to form the new combined thermal switch 10 of the present invention. While keeping the other parameters unchanged, the helium-4 gas was successfully liquefied, and the temperature of the 1K disk dropped to about 1K, indicating that the heat leakage was greatly reduced.

[0066] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A combined thermal switch, characterized in that: include: A thermal switch body, wherein the thermal switch body has a hot end and a cold end that are arranged opposite to each other; A first superconducting layer, wherein the first superconducting layer is disposed on an end surface of the hot end and is closely disposed with the end surface of the hot end; a second superconducting layer, the second superconducting layer being arranged on a side of the first superconducting layer away from the hot end, the first superconducting layer and the second superconducting layer being arranged in a stacked manner; Wherein, the superconducting transition temperature of the first superconducting layer is lower than the superconducting transition temperature of the second superconducting layer.

2. The combined thermal switch according to claim 1, characterized in that: The first superconducting layer is an indium sheet.

3. The combined thermal switch according to claim 1, characterized in that: The combined thermal switch includes multiple layers of the first superconducting layer, and the multiple layers of the first superconducting layer are stacked and arranged between the second superconducting layer and the end surface of the hot end.

4. The combined thermal switch according to claim 1, characterized in that: The second superconducting layer is an aluminum oxide spacer.

5. The combined thermal switch according to claim 1, characterized in that: The radius of the cross section of the first superconducting layer is greater than or equal to the radius of the end surface of the hot end.

6. The combined thermal switch according to claim 1, characterized in that: The radius of the cross section of the second superconducting layer is greater than or equal to the radius of the end surface of the hot end.

7. The combined thermal switch according to claim 1, characterized in that: The thickness of the first superconducting layer along the axial direction is smaller than the thickness of the second superconducting layer along the axial direction.

8. The combined thermal switch according to claim 1, characterized in that: The first superconducting layer is arranged in a ring shape; And / or, the second superconducting layer is arranged in a ring shape.

9. The combined thermal switch according to claim 1, characterized in that: The thermal switch body includes any one of an air gap thermal switch and a convection thermal switch.

10. A refrigerator, characterized in that: It comprises a combined thermal switch as claimed in any one of claims 1 to 9.

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