A thermal breaking component, a liquid-gap thermal switch and its switching method

Abstract

The present invention discloses a thermal breaking component, a liquid-gap thermal switch and a switching method thereof, relating to the technical field of thermal switches. The thermal breaking component includes a hot-end body, a cold-end body and a support cylinder. A heat conduction cavity is formed among the hot-end body, the cold-end body and the support cylinder, and a heat conduction medium can be filled in the heat conduction cavity. A hot-end extension cylinder is fixed on the surface of the hot-end body close to the cold-end body, and a cold-end extension column is fixed on the surface of the cold-end body close to the hot-end body. There is a heat conduction gap between the hot-end extension cylinder and the cold-end extension column. The heat conduction medium includes a liquid heat conduction medium. When the liquid heat conduction medium fills the heat conduction gap, heat conduction can be carried out between the hot-end body and the cold-end body. The liquid-gap thermal switch includes a thermal breaking component and an adsorption pump. The adsorption pump is connected to the heat conduction cavity through a communication pipe. The present invention realizes the opening of the thermal breaking component by filling the heat conduction gap with a liquid heat conduction medium having better heat conductivity, and has a better switching ratio.

Description

Technical Field

[0001] The present invention relates to the technical field of thermal switches, and particularly to a thermal breaking component, a liquid gap type thermal switch and a switching method thereof. Background Art

[0002] With the development of space science, disciplines such as microgravity fundamental physics, space astronomy, space environment and space physics, new space application technologies, and deep space exploration have an increasingly wide range of requirements for extremely low temperatures, and thus the research on extremely low temperature refrigeration technology has gradually attracted the attention of the scientific community. The universe is an extremely low temperature environment (about 3K). To observe deep space and improve the sensitivity of detectors and the thermal stability of the entire system, there are extremely low requirements for the temperature of equipment. Extremely low temperature refrigeration is also a key technology for related research such as condensed matter physics and microgravity physics in space stations. For example, to study the tricritical exponent problem of 3He-4He in the International Space Station, an extremely low temperature environment of 0.9 K is required.

[0003] The adsorption refrigeration technology that emerged in the late 1980s of the 20th century has the advantages of long life, no moving parts, no vibration, high reliability, no electromagnetic interference, etc. By using different working fluids, the refrigeration temperature can cover the temperature range from several hundred mK to room temperature, and the adsorption bed can be easily arranged away from the cold end. Therefore, adsorption refrigerators are increasingly favored by space and aerospace technology applications.

[0004] The thermal switch is a key component of the adsorption refrigerator, which can control the heat transfer between the control body (evaporator or adsorption bed) and the heat sink. By switching the thermal switch, the opening or closing of the heat transfer can be achieved. The research on space thermal switches abroad began with the space thermal switch applied in the Apollo program in the United States in the 1960s. It has developed with the development of aerospace technology. Currently, various types of thermal switches have been developed, which can be classified into contact type, air gap type, field effect type, and heat pipe type according to the thermal resistance principle.

[0005] Currently, the widely used air gap type thermal switch changes the heat transfer capacity of the thermal switch by adding or extracting gas working fluid between the heat conducting sheets, thereby realizing the opening and closing of the thermal switch. Specifically, as shown in the existing patent "An adsorption pump and an air gap type thermal switch" disclosed in CN110108060B, it includes a hot end, a cold end, a support member, and an adsorption pump. When heating the hot end of the adsorption pump, the adsorption capacity of the activated carbon inside decreases with the increase of temperature, thereby realizing the outgassing process. When there is helium gas with a certain pressure in the gap, its thermal resistance is small, forming a substantial heat conduction. When the heating of the hot end of the adsorption pump stops, the adsorption capacity of the activated carbon in the adsorption pump increases, and thus starts to pump air, making the inside of the thermal switch close to vacuum, increasing the thermal resistance values of the cold end and the hot end, and realizing a substantial heat break.

[0006] However, the existing air-gap thermal switch has a relatively complex structure and requires an adsorption pump to extract the gas in the thermal switch. Moreover, for the same substance, the thermal conductivity of the liquid is better than that of the gas. Therefore, the air-gap thermal switch has the disadvantage of a small switching ratio.

[0007] Therefore, there is an urgent need in the art for a thermal breaking component, a liquid-gap thermal switch and its switching method to solve the above problems. Summary of the Invention

[0008] The object of the present invention is to provide a thermal breaking component, a liquid-gap thermal switch and its switching method to solve the problems existing in the above-mentioned prior art, and utilize the characteristic of good thermal conductivity of the liquid to improve the switching ratio of the thermal breaking component.

[0009] To achieve the above object, the present invention provides the following solutions:

[0010] The present invention discloses a thermal breaking component, including a hot-end body, a cold-end body and a support cylinder. The hot-end body and the cold-end body are respectively fixed at both ends of the support cylinder. A heat conduction cavity is formed among the hot-end body, the cold-end body and the support cylinder. The heat conduction cavity can be filled with a heat conduction medium. A hot-end extension cylinder is fixed on the surface of the hot-end body close to the cold-end body, and a cold-end extension column is fixed on the surface of the cold-end body close to the hot-end body. There is a heat conduction gap between the hot-end extension cylinder and the cold-end extension column. The heat conduction medium includes a liquid heat conduction medium. When the liquid heat conduction medium fills the heat conduction gap, the hot-end body and the cold-end body can conduct heat.

[0011] Preferably, the inner diameter of the hot-end extension cylinder is larger than the diameter of the cold-end extension column.

[0012] Preferably, the liquid heat conduction medium is liquid helium.

[0013] Preferably, the hot-end body and the hot-end extension cylinder are integrally formed, and the cold-end body and the cold-end extension column are integrally formed.

[0014] Preferably, the materials of the hot-end body, the cold-end body, the hot-end extension cylinder and the cold-end extension column are all oxygen-free copper.

[0015] Preferably, the material of the support cylinder is stainless steel.

[0016] The present invention discloses a liquid-gap thermal switch, including a thermal breaking component, and further including an adsorption pump. The adsorption pump is connected to the heat conduction cavity through a communication pipe.

[0017] The present invention discloses a switching method for a liquid-gap thermal switch, including the following steps:

[0018] On state: First, install the hot starting component so that the hot end body is connected to the heat source and the cold end body is connected to the cold source. At this time, the heat conduction medium is in a liquid state, and the liquid heat conduction medium fills the heat conduction gap, connecting the cold end body to the hot end body. The heat of the cold source is finally transferred to the heat source through the cold end body, the cold end extension column, the liquid at the heat conduction gap, the hot end extension column, and the hot end body;

[0019] Off state: When it is necessary to disconnect the connection between the hot end body and the cold end body, first use the adsorption pump to pump out the heat conduction medium in the heat conduction cavity. At this time, there is no liquid heat conduction medium at the heat conduction gap, making it impossible to conduct heat between the hot end extension cylinder and the cold end extension column.

[0020] The present invention has achieved the following technical effects compared with the prior art:

[0021] The present invention uses a liquid with good thermal conductivity as the heat conduction medium. When it fills the heat conduction gap, the connection of the hot opening and closing component can be realized, and the switching ratio is relatively large. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the following will briefly introduce the drawings required in the embodiments. Obviously, the drawings in the following description are only some embodiments of the present invention. For those of ordinary skill in the art, without creative efforts, other drawings can be obtained based on these drawings.

[0023] Figure 1 It is a structural schematic diagram of the hot opening and closing component in Embodiment 1;

[0024] In the figure: 1 - hot end body; 2 - cold end body; 3 - support cylinder; 4 - hot end extension cylinder; 5 - cold end extension column. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0025] The following will clearly and completely describe the technical solutions in the embodiments of the present invention with reference to the drawings in the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, rather than all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present invention.

[0026] The purpose of the present invention is to provide a hot opening and closing component, a liquid gap type thermal switch and its switching method to solve the problems existing in the above prior art, and utilize the characteristic of good thermal conductivity of the liquid to improve the switching ratio of the hot opening and closing component.

[0027] To make the above objects, features, and advantages of the present invention more obvious and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0028] Embodiment 1

[0029] As Figure 1 shown, this embodiment provides a thermal breaking component, including a hot-end body 1, a cold-end body 2, and a support cylinder 3. The hot-end body 1 and the cold-end body 2 are arranged oppositely, and the hot-end body 1 and the cold-end body 2 are respectively fixed at the upper and lower ends of the support cylinder 3. A heat conduction cavity is jointly formed among the hot-end body 1, the cold-end body 2, and the support cylinder 3, and a heat conduction medium can be filled in the heat conduction cavity. A hot-end extension cylinder 4 is fixed on the surface of the hot-end body 1 close to the cold-end body 2. The hot-end extension cylinder 4 is a cylindrical structure. A cold-end extension column 5 is fixed on the surface of the cold-end body 2 close to the hot-end body 1. The cold-end extension column 5 is a small cylindrical structure, and there is a heat conduction gap between the hot-end extension cylinder 4 and the cold-end extension column 5. The heat conduction medium includes a liquid heat conduction medium. When the liquid heat conduction medium fills the heat conduction gap, heat conduction can occur between the hot-end body 1 and the cold-end body 2.

[0030] During actual use, the hot-end body 1 is connected to a heat source, and the cold-end body 2 is connected to a cold source. After the heat conduction gap is filled with the heat conduction medium. Heat will sequentially pass through the cold source, the cold-end body 2, the cold-end extension column 5, the liquid heat conduction medium at the heat conduction gap, the hot-end extension cylinder 4, and the hot-end body 1, and then be transmitted to the heat source, thereby playing a role in cooling the heat source.

[0031] In this embodiment, the inner diameter of the hot-end extension cylinder 4 is larger than the diameter of the cold-end extension column 5. As Figure 1 shown, a part of the cold-end extension column 5 is located inside the lower end of the hot-end extension cylinder 4, and the outer wall of the cold-end extension column 5 and the inner wall of the hot-end extension cylinder 4 form a heat conduction gap.

[0032] In this embodiment, the liquid heat conduction medium is liquid helium. However, during actual use, since the temperature in the heat conduction cavity will change, when the temperature in the heat conduction cavity is relatively high, liquid helium will turn into helium gas, and when the temperature is relatively low, helium gas will turn into liquid helium. Of course, during the conversion process, it will not all be converted into one form. Therefore, there are generally two states of helium gas and liquid helium in the heat conduction cavity. Exactly because of this, compared with the existing air-gap thermal switch (such as patent CN110108060B), the heat conduction gap in this embodiment is smaller, while the heat conduction cavity is larger, which is used to accommodate the larger volume of helium gas after vaporization.

[0033] In this embodiment, the hot-end body 1 and the hot-end extension cylinder 4 are integrally formed, and the cold-end body 2 and the cold-end extension column 5 are integrally formed.

[0034] In this embodiment, the hot end body 1, the cold end body 2, the hot end extension cylinder 4, and the cold end extension column 5 are all made of materials with high thermal conductivity, including but not limited to oxygen-free copper.

[0035] In this embodiment, the support cylinder 3 can be made of materials with good heat insulation, including but not limited to stainless steel.

[0036] Embodiment Two

[0037] This embodiment provides a liquid gap type thermal switch, which includes the thermal on-off component disclosed in Embodiment One. In addition, it also includes an adsorption pump. For the adsorption pump, the adsorption pump in Patent CN110108060B can be used, that is, it includes a cold end, a hot end, and a support member. The cold end, the support member, and the hot end are connected in sequence to form a sealed structure. The sealed structure is filled with an adsorbent, and the adsorbent is activated carbon. Extension members are provided on both the cold end and the hot end. The extension members extend into the adsorbent and are isolated from the support member. For the more specific structural connection relationship, reference can be made to the original text of Patent CN110108060B, and it will not be elaborated here. Of course, those skilled in the art can also replace it with an adsorption pump of other structures, not limited to this one only. The adsorption pump is connected to the heat conduction cavity through a connecting pipe. Specifically, one end of the connecting pipe passes through the cold end body 2 and extends into the heat conduction cavity.

[0038] Embodiment Three

[0039] This embodiment provides a switching method for a liquid gap type thermal switch. Based on the liquid gap type thermal switch disclosed in Embodiment Two, it includes the following steps:

[0040] On state: First, install the hot start component so that the hot end body 1 is connected to the heat source, the temperature of the heat source is 30K, and the cold end body 2 is connected to the cold source, the temperature of the cold source is 4K. Of course, the specific temperatures of the heat source and the cold source are not limited to this one only. At this time, due to the low temperature of the cold source, the temperature of the cold end body 2 and the heat conduction cavity is also low, and lower than the boiling point of the liquid heat conduction medium, making it unable to vaporize. Therefore, the heat conduction medium is in a liquid state (i.e., liquid helium), and because there is more liquid heat conduction medium, it can fill the heat conduction gap. Connect the cold end body 2 to the hot end body 1. Specifically, in the heat transfer process, the heat of the cold source is transferred to the heat source through the cold end body 2, the cold end extension column 5, the liquid at the heat conduction gap, the hot end extension column, and the hot end body 1, so as to cool the heat source. During this process, the adsorption pump is in the off state, or the connecting pipe is in the off state.

[0041] Disconnected state: Due to experimental requirements, when the staff needs to heat the heat source connected to the hot-end body 1 separately and avoid the influence of the cold-end body 2, the connection between the hot-end body 1 and the cold-end body 2 needs to be disconnected at this time. First, start the adsorption pump. For example, in Patent CN110108060B, it is necessary to start the cold source at the cold end of the adsorption pump to cool the adsorbent inside the adsorption pump, thereby enhancing its adsorption capacity, and use the adsorption pump to pump out the heat-conducting medium in the heat-conducting cavity. At this time, there is no liquid heat-conducting medium in the heat-conducting cavity and the heat-conducting gap, and there is almost no helium gas. It can be said that the heat-conducting cavity is almost in a vacuum. Even if there is helium gas, it is trace helium gas. Trace helium gas does not have heat-conducting ability in the narrow heat-conducting gap, so that heat conduction cannot be carried out between the hot-end extension cylinder 4 and the cold-end extension column 5.

[0042] Then enter the next cycle, that is, when it is necessary to connect the hot-end body 1 and the cold-end body 2 again, start the heater at the hot end of the adsorption pump to heat the hot end of the adsorption pump, so that the temperature of the adsorbent in the adsorption pump rises, thereby reducing its adsorption capacity, causing the helium gas in the adsorption pump to be discharged and enter the thermal switch component again through the connecting pipe. Once it enters the heat-conducting cavity, the cold source at the cold-end body 2 will cool it, causing it to condense and liquefy here and fill the heat-conducting gap, so as to realize the reconnection of the hot-end body 1 and the cold-end body 2. Next is the disconnected state. Just repeat the above working steps continuously, so it will not be elaborated here.

[0043] In the present invention, specific examples are used to elaborate the principle and implementation mode of the present invention. The description of the above embodiments is only used to help understand the method and its core idea of the present invention; at the same time, for those of ordinary skill in the art, according to the idea of the present invention, there will be changes in the specific implementation mode and application scope. To sum up, the content of this specification should not be construed as a limitation to the present invention.

Claims

1. A thermal breaking component, comprising a hot end body, a cold end body and a support cylinder, wherein the hot end body and the cold end body are respectively fixed at two ends of the support cylinder, a heat conduction cavity is formed among the hot end body, the cold end body and the support cylinder, and a heat conduction medium can be filled in the heat conduction cavity, and is characterized in that: A hot-end extension cylinder is fixed on one side of the hot-end body close to the cold-end body, and a cold-end extension column is fixed on one side of the cold-end body close to the hot-end body. There is a heat conduction gap between the hot-end extension cylinder and the cold-end extension column. The heat conduction medium includes a liquid heat conduction medium. When the liquid heat conduction medium fills the heat conduction gap, the hot-end body and the cold-end body can conduct heat; The inner diameter of the hot-end extension cylinder is larger than the diameter of the cold-end extension column, and the cold-end extension column can extend into the hot-end extension cylinder.

2. The thermal interruption component according to claim 1, characterized in that: The liquid heat conduction medium is liquid helium.

3. The thermal interruption component according to claim 1, characterized in that: The hot-end body and the hot-end extension cylinder are integrally formed, and the cold-end body and the cold-end extension column are integrally formed.

4. The thermal interruption component according to claim 1, characterized in that: The materials of the hot-end body, the cold-end body, the hot-end extension cylinder and the cold-end extension column are all oxygen-free copper.

5. The thermal interruption component according to claim 1, characterized in that: The material of the support cylinder is stainless steel.

6. A liquid gap type thermal switch, characterized in that: It includes the hot-switching component according to any one of claims 1-5, and further includes an adsorption pump, and the adsorption pump is connected to the heat conduction cavity through a connecting pipe.

7. A switching method for a liquid gap thermal switch, characterized in that Based on the liquid-gap thermal switch of claim 6, it includes the following steps: Open state: First, install the hot-start component so that the hot-end body is connected to the heat source and the cold-end body is connected to the cold source. At this time, the heat conduction medium is in a liquid state, and the liquid heat conduction medium fills the heat conduction gap, so that the cold-end body is connected to the hot-end body. The heat of the cold source is transmitted to the heat source through the cold-end body, the cold-end extension column, the liquid at the heat conduction gap, the hot-end extension column and the hot-end body; Disconnected state: When it is necessary to disconnect the connection between the hot-end body and the cold-end body, first use the adsorption pump to pump out the heat conduction medium in the heat conduction cavity. At this time, there is no liquid heat conduction medium at the heat conduction gap, so that heat conduction cannot be carried out between the hot-end extension cylinder and the cold-end extension column.

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