Thermal switches and dilution refrigeration equipment

Abstract

The present invention provides a thermal switch and a dilution refrigeration device, which relate to the technical field of dilution refrigeration. The thermal switch includes a first heat conductor, a second heat conductor and a shell. The shell is constructed as a tubular structure with two ends open. The first heat conductor contacts the first target object, the first adjustment part is installed at the upper end opening of the shell, the first elastic part is located in the shell and connected to the first adjustment part, and the first joint part is connected to the first adjustment part through the first elastic part. The second heat conductor is installed at the lower end opening of the shell and contacts the second target object, and has a first state in which the first joint part is pressed against the second target object in response to the second target object being higher than the target temperature, thereby forming heat conduction with the first heat conductor, and a second state in which the second target object is separated from the first joint part in response to the second target object being lower than the target temperature, thereby forming thermal isolation with the first heat conductor. The deformation amount generated by the first elastic part when the second heat conductor is in the first state is adjusted by the first adjustment part to change the contact pressure between the second heat conductor and the first joint part.

Description

Technical Field

[0001] The present invention relates to the technical field of dilution refrigeration, and more particularly to a thermal switch and a dilution refrigeration device. Background Art

[0002] With the rapid development of science and technology, the demand for extremely low-temperature environments is growing. In fields such as physics, materials science, quantum computing, and deep space exploration, creating ultra-low-temperature environments close to absolute zero (0 K) has become a key technical bottleneck. Although traditional refrigeration technologies (such as liquid nitrogen cooling and helium cycle refrigeration) can achieve rapid cooling in conventional temperature ranges, their efficiency decreases significantly in ultra-low temperature ranges (temperatures below 100 mK), and they are unable to meet the requirements of large temperature differences and high stability. In this context, the dilution refrigerator, a low-temperature refrigeration device based on the thermodynamic mixing effect, has become the core equipment for achieving ultra-low-temperature environments due to its unique refrigeration mechanism and excellent performance advantages.

[0003] The dilution refrigerator currently in widespread use is a type of refrigerator that utilizes helium-3 ( 3 He) and helium-4 ( 4 He) mixed liquid phase separation characteristics to achieve ultra-low temperature refrigeration equipment. In the dilution refrigerator, 3 He- 4 The He mixture is placed in a closed circulation system, which usually includes key components such as a mixing chamber, a distiller, a condenser, and a heat exchanger. 3 He- 4 When the temperature of the He mixture drops below about 0.87 K, it separates into two phases, the upper phase is 3 The concentrated phase has a higher He concentration, and the lower layer is a dilute phase with a lower He concentration, which is about 6.4%-6.6%. 3 He draws out and makes 3 He vapor condenses into 3 The He solution then flows back into the concentrated phase. At this time, since the chemical potential of the He atoms in the dilute phase is higher than that in the concentrated phase, the He atoms will pass through the phase interface separating the concentrated phase and the dilute phase, thereby performing dilution refrigeration.

[0004] Dilution refrigerators typically require pre-cooling. During this pre-cooling phase, a pulse tube refrigerator (PTC) is used to rapidly reduce the temperature from room temperature (approximately 300K) to a cryogenic temperature, saving time and energy. After the pre-cooling phase is complete, the dilution refrigeration cycle begins. During the pre-cooling phase, the pulse tube refrigerator exchanges heat with the dilution refrigeration core via multiple cold plates and thermal switches. When the dilution refrigeration core temperature exceeds the cryogenic temperature, the thermal switch remains open to direct heat to the pulse tube refrigerator. When the dilution refrigeration core temperature reaches the cryogenic temperature, the thermal switch closes, allowing the internal dilution refrigeration cycle to continue cooling. In related art, the entire dilution refrigeration system typically features multiple cold plates, such as a room temperature zone cold plate near the pulse tube refrigerator, a 30K cold plate, and a 4K cold plate, as well as an evaporator cold plate and a mixing chamber cold plate near the dilution refrigeration core. Conventional thermal switch structures cannot be flexibly adjusted to maintain good thermal conductivity across different cooling ranges. Therefore, optimizing the thermal switch structure to improve its adaptability to different cooling ranges has become a pressing technical challenge. Summary of the Invention

[0005] In view of this, the present invention provides a thermal switch and a dilution refrigeration device, which can adapt to usage scenarios at different target temperatures and can be flexibly adjusted to improve heat transfer efficiency.

[0006] In order to achieve the above-mentioned purpose, the present invention provides a thermal switch, including a shell, which is constructed as a tubular structure with openings at both ends; a first heat conductor, which contacts a first target object, including: a first adjustment part, which is installed at the upper end opening of the above-mentioned shell; a first elastic part, which is located in the above-mentioned shell and connected to the above-mentioned first adjustment part; a first joint part, which is connected to the above-mentioned first adjustment part through the above-mentioned first elastic part; a second heat conductor, which is installed at the lower end opening of the above-mentioned shell and contacts the second target object, and has a first state in which, in response to the above-mentioned second target object being higher than the target temperature, the above-mentioned first joint part is pressed against the above-mentioned first joint part to form heat conduction with the above-mentioned first heat conductor, and a second state in which, in response to the above-mentioned second target object being lower than the target temperature, the above-mentioned first joint part is separated from the above-mentioned first joint part to form thermal isolation with the above-mentioned first heat conductor; the above-mentioned first elastic part is constructed so that the deformation amount generated when the above-mentioned second heat conductor is in the first state can be adjusted by the above-mentioned first adjustment part to change the contact pressure between the above-mentioned second heat conductor and the above-mentioned first joint part.

[0007] According to an embodiment of the present invention, a limiting boss is formed on the inner wall of the housing, which is adapted to prevent the first engaging portion from moving toward the second heat conducting member under the driving of the first elastic member.

[0008] According to an embodiment of the present invention, the second heat conducting member is further configured to reciprocate in a vertical direction so that the second heat conducting member switches between the first state and the second state in response to different target temperatures.

[0009] According to an embodiment of the present invention, the first heat-conducting member and the second heat-conducting member are arranged sequentially in the vertical direction, the second heat-conducting member forms heat conduction with the first heat-conducting member at the first position, the distance between the first position and the limiting boss is a preset spacing, and the second heat-conducting member is configured to move back and forth in the vertical direction to change the size of the preset spacing, thereby adjusting the contact time of the second heat-conducting member and the first joint portion.

[0010] According to an embodiment of the present invention, the above-mentioned second heat-conducting member includes: a second joint portion, suitable for pressing against or disengaging from the above-mentioned first joint portion; a driving portion, one end of which is connected to the above-mentioned second joint portion and is configured to expand or contract in response to temperature changes to drive the above-mentioned second joint portion to move in a vertical direction; a second adjusting portion, installed at the lower end opening of the above-mentioned shell and connected to the other end of the above-mentioned driving portion, suitable for adjusting the above-mentioned preset spacing.

[0011] According to an embodiment of the present invention, the above-mentioned second adjustment part includes: a second end cap, which is connected to the above-mentioned driving part; a second sleeve, which is sleeved on the outside of the above-mentioned second end cap and is threadedly connected to the above-mentioned shell to drive the above-mentioned second end cap to reciprocate in the vertical direction through rotation.

[0012] According to an embodiment of the present invention, the above-mentioned first adjustment part includes: a first end cap, which is connected to the above-mentioned first elastic member; a first sleeve, which is sleeved on the outside of the above-mentioned first end cap and is threadedly connected to the above-mentioned shell to drive the above-mentioned first end cap to reciprocate in the vertical direction through rotation.

[0013] According to an embodiment of the present invention, the above-mentioned first end cap is constructed as a hollow cylindrical structure, and the above-mentioned first heat conductor also includes: an upper limit member, which is sealed on the upper end of the above-mentioned first end cap; a lower limit member, which is arranged in the above-mentioned first end cap, and passes through the lower end of the above-mentioned first end cap and presses against the above-mentioned first joint; a second elastic member, and the two ends of the above-mentioned second elastic member are respectively pressed against the above-mentioned upper limit member and the above-mentioned lower limit member, and are configured to be in a compressed state to increase the contact pressure between the above-mentioned first joint and the above-mentioned second heat conductor.

[0014] According to an embodiment of the present invention, the first end cap, the first elastic member and the first joint portion are made of the same material, and the thermal conductivity of the same material is greater than the thermal conductivity of the housing.

[0015] The present invention also provides a dilution refrigeration device, comprising: a pre-cooling unit, including a cold head and a pre-cooling-stage cold plate, the cold head is suitable for cooling the pre-cooling-stage cold plate, and the pre-cooling-stage cold plate is used as a first target object; a dilution refrigeration unit, including a dilution refrigeration core and a core-stage cold plate, and the core-stage cold plate is used as a second target object, and the dilution refrigeration core is configured to cool the core-stage cold plate in response to the core-stage cold plate being lower than the target temperature; a thermal switch as in any of the above embodiments is arranged between the pre-cooling-stage cold plate and the core-stage cold plate.

[0016] The thermal switch provided by the present invention has a structure in which, when the temperature of the second target object is higher than the target temperature, the second thermal conductor contacts the first thermal conductor and presses against it with a certain pressure, so that the temperature of the second target object is transferred to the first target object through the second thermal conductor and the first thermal conductor. When the temperature of the second target object drops below the target temperature, the second thermal conductor separates from the first thermal conductor, and heat is no longer transferred between the first target object and the second target object. By adjusting the contact pressure between the second thermal conductor and the first thermal conductor, the thermal switch can achieve good heat transfer performance and accurate and rapid response capabilities when applied to different target temperatures. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 It is a three-dimensional schematic diagram of the thermal switch provided by the present invention;

[0018] Figure 2 is a half-section schematic diagram of the thermal switch provided by the present invention, with the housing removed;

[0019] Figure 3 is a schematic cross-sectional view of the thermal switch provided by the present invention;

[0020] Figure 4 is a cross-sectional schematic diagram of the thermal switch provided by the present invention;

[0021] Figure 5 yes Figure 4 A partial cross-sectional view of the exemplary embodiment shown with the housing removed, illustrating the lower stop;

[0022] Figure 6 This is a schematic diagram of the working process of the thermal switch provided by the present invention;

[0023] Figure 7 It is a schematic diagram of the dilution refrigeration equipment provided by the present invention.

[0024] In the drawings, the meanings of the reference numerals are as follows:

[0025] 1. A first heat conducting member;

[0026] 11. First adjustment unit;

[0027] 111. First end cap;

[0028] 112. First sleeve;

[0029] 12. a first elastic member;

[0030] 13. a first joint;

[0031] 14. Upper limit piece;

[0032] 15. Lower limiter;

[0033] 151. Tighten the bolts;

[0034] 152. Limiting platform;

[0035] 153. Subject;

[0036] 16. a second elastic member;

[0037] 2. Second heat conducting member;

[0038] 21. Second adjustment unit;

[0039] 211, second end cap;

[0040] 212, second sleeve;

[0041] 22. Driving unit;

[0042] 23. second joint;

[0043] 3. Shell;

[0044] 31. Limiting boss;

[0045] 4. Pre-cooling unit;

[0046] 41. Cold head;

[0047] 42. Pre-cooling cold plate;

[0048] 5. Dilution refrigeration unit;

[0049] 51. Dilution refrigeration core;

[0050] 52. Core-level cold cuts;

[0051] 6. Thermal switch. DETAILED DESCRIPTION

[0052] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. However, it should be understood that these descriptions are exemplary only and are not intended to limit the scope of the present invention. In the following detailed description, for ease of explanation, many specific details are set forth to provide a comprehensive understanding of embodiments of the present invention. However, it is apparent that one or more embodiments may also be implemented without these specific details. In addition, in the following description, descriptions of known structures and technologies are omitted to avoid unnecessary confusion of the concept of the present invention.

[0053] The terms used herein are only for describing specific embodiments and are not intended to limit the present invention. The terms "comprise", "include", etc. used herein indicate the presence of the features, steps, operations and / or components, but do not exclude the presence or addition of one or more other features, steps, operations or components.

[0054] All terms used herein (including technical and scientific terms) have the meanings commonly understood by those skilled in the art unless otherwise defined. It should be noted that the terms used herein should be interpreted as having a meaning consistent with the context of this specification and should not be interpreted in an idealized or overly rigid manner.

[0055] When expressions such as "at least one of A, B, and C, etc." are used, they should generally be interpreted in accordance with the meaning commonly understood by those skilled in the art (for example, "a system having at least one of A, B, and C" should include but is not limited to a system having A alone, B alone, C alone, A and B, A and C, B and C, and / or A, B, C, etc.).

[0056] Figure 1 is a three-dimensional schematic diagram of the thermal switch provided by the present invention, Figure 2 This is a half-section schematic diagram of the thermal switch provided by the present invention, with the housing removed. Figure 3 is a schematic cross-sectional view of the thermal switch provided by the present invention, Figure 4 is a cross-sectional schematic diagram of the thermal switch provided by the present invention, Figure 5 yes Figure 4 The illustrated exemplary embodiment is a partial cross-sectional view with the housing removed, showing the lower stop.

[0057] An exemplary embodiment of the present invention provides a thermal switch, such as Figures 1 to 5As shown, it includes a first heat-conducting member 1, a second heat-conducting member 2 and a shell 3. The shell 3 is constructed as a tubular structure with two ends open. The first heat-conducting member 1 contacts the first target object and includes a first adjustment portion 11, a first elastic member 12 and a first joint portion 13. The first adjustment portion 11 is installed at the upper end opening of the shell 3, the first elastic member 12 is located in the shell 3 and connected to the first adjustment portion 11, and the first joint portion 13 is connected to the first adjustment portion 11 through the first elastic member 12. The second heat-conducting member 2 is installed at the lower end opening of the shell 3 and contacts the second target object. The second heat-conducting member 2 has a first state in which it presses against the first joint portion 13 in response to the second target object being higher than the target temperature, forming heat conduction with the first heat-conducting member 1, and a second state in which it detaches from the first joint portion 13 in response to the second target object being lower than the target temperature, forming thermal isolation with the first heat-conducting member 1. The first elastic member 12 is constructed so that the deformation amount generated by the second heat-conducting member 2 in the first state can be adjusted by the first adjustment portion 11 to change the contact pressure between the second heat-conducting member 2 and the first joint portion 13.

[0058] In such an embodiment, the first heat conductor 1 and the second heat conductor 2 are respectively installed at the openings at both ends of the shell 3 to seal the shell 3 to form a sealed cavity, and the sealed cavity is configured to be in a vacuum state. The first heat conductor 1 is in contact with the first target object, and the second heat conductor 2 is in contact with the second target object. When the temperature of the second target object is higher than the target temperature, the second heat conductor 2 is in contact with the first heat conductor 1 and pressed with a certain pressure, so that the temperature of the second target object is transferred to the first target object through the second heat conductor 2 and the first heat conductor 1. When the temperature of the second target object drops below the target temperature, the second heat conductor 2 is separated from the first heat conductor 1. Since the sealed cavity is in a vacuum state, heat is no longer transferred between the first target object and the second target.

[0059] Affected by different target temperatures, the contact pressure between the second heat-conducting member 2 and the first heat-conducting member 1 will change. Since the contact surfaces of the second heat-conducting member 2 and the first heat-conducting member 1 are not ideal smooth surfaces, the change in contact pressure will affect the heat transfer efficiency. By adjusting the deformation of the first elastic member 12 through the first adjustment part 11, the contact pressure between the second heat-conducting member 2 and the first heat-conducting member 1 can be adjusted according to different target temperatures, thereby improving the heat transfer efficiency and reducing the time required for heat transfer.

[0060] In an exemplary embodiment, a limiting boss 31 is formed on the inner wall of the housing 3 , which is adapted to prevent the first engaging portion 13 from moving toward the second heat-conducting member 2 under the drive of the first elastic member 12 .

[0061] In this embodiment, when the second heat-conducting member 2 is in the first state, the first elastic member 12 is compressed, and the second heat-conducting member 2 resists the elastic force of the first elastic member 12. As the temperature of the second target object gradually decreases, the contact pressure between the second heat-conducting member 2 and the first engaging portion 13 gradually decreases until the limiting boss 31 resists the elastic force of the first elastic member 12. At this point, the second heat-conducting member 2 and the first engaging portion 13 disengage, and the temperature of the second target object drops below the target temperature.

[0062] According to an embodiment of the present invention, the second heat conducting member 2 is further configured to reciprocate in the vertical direction so that the second heat conducting member 2 switches between the first state and the second state in response to different target temperatures.

[0063] In such an embodiment, when the first target object and the second target object change, or the target temperature changes, the separation temperature of the thermal switch is changed by adjusting the vertical position of the second heat conductor 2, thereby improving the flexibility of the thermal switch and reducing the manufacturing cost.

[0064] Figure 6 This is a schematic diagram of the working process of the thermal switch provided by the present invention.

[0065] According to an embodiment of the present invention, Figure 6 As shown, the first heat-conducting member 1 and the second heat-conducting member 2 are arranged sequentially in the vertical direction, the second heat-conducting member 2 forms heat conduction with the first heat-conducting member 1 at the first position, the distance between the first position and the limiting boss 31 is a preset spacing, and the second heat-conducting member 2 is configured to move back and forth in the vertical direction to change the size of the preset spacing, thereby adjusting the contact time between the second heat-conducting member 2 and the first joint portion 13.

[0066] In such an embodiment, the tubular housing 3 is arranged in a vertical direction, and the first heat conducting member 1 and the second heat conducting member 2 are also arranged in sequence at both ends of the housing 3 in the vertical direction. The first adjusting portion 11, the first elastic member 12, and the first joint portion 13 of the first heat conducting member 1 are connected in sequence from top to bottom in the vertical direction. In response to the second target object temperature being lower than the target temperature, the second heat conducting member 2 presses against the first joint portion 13 and compresses the first elastic member 12. The pressing position, i.e., the first position, is located above the limiting boss 31. As the second target object temperature drops, the compression amount of the first elastic member 12 decreases, and the contact pressure decreases until the limiting boss 31 restricts the first joint portion 13 from continuing to move. Then, the second heat conducting member 2 disengages from the first joint portion 13. After the second target object temperature stabilizes, the upper surface of the second heat conducting member 2 (i.e., the contact surface with the first joint portion 13) is located at the second position, which is located below the limiting boss 31. The distance between the first position and the limiting boss 31 is a preset spacing H. For example, as the second heat-conducting member 2 moves upward and the preset spacing H increases, the time required for the second heat-conducting member 2 and the first heat-conducting member 1 to switch from heat conduction to thermal isolation becomes longer. During this period, more heat is transferred from the second target object to the first target object. When the second heat-conducting member 2 and the first heat-conducting member 1 form thermal isolation, the temperature of the second target object becomes lower, and the final isolation spacing h becomes larger. This enables the thermal switch to be suitable for use scenarios at different target temperatures and the isolation temperature can be flexibly adjusted.

[0067] In an exemplary embodiment, the second heat-conducting member 2 includes a second adjusting portion 21, a driving portion 22, and a second engaging portion 23. The second engaging portion 23 is adapted to press against or disengage from the first engaging portion 13. One end of the driving portion 22 is connected to the second engaging portion 23 and is configured to expand or contract in response to temperature changes, thereby driving the second engaging portion 23 to move vertically. The second adjusting portion 21 is rotatably mounted on the housing 3 and is connected to the other end of the driving portion 22, adapted to adjust the preset spacing H.

[0068] In such an embodiment, the second joint portion 23, the driving portion 22 and the second adjusting portion 21 of the second heat-conducting member 2 are connected in sequence from top to bottom in the vertical direction. The second joint portion 23 is roughly the same shape as the first joint portion 13, so as to have a larger contact area when pressed, thereby improving the heat transfer efficiency. The driving portion 22 can expand as the temperature rises and contract as the temperature drops. It should be noted that the thermal expansion coefficient of the driving portion 22 is greater than that of the shell 3, so that when the temperature of the second target object drops below the target temperature, the contraction amount of the driving portion 22 is greater than the contraction amount of the shell 3, thereby separating the second joint portion 23 from the first joint portion 13. The second adjusting portion 21 is rotatably mounted on the shell 3 and can produce a vertical displacement relative to the shell 3, so that the second heat-conducting member 2 moves in the vertical direction as a whole, thereby adjusting the preset spacing H.

[0069] Exemplarily, the driving part 22 is preferably made of pure aluminum, and the shell 3 is preferably made of stainless steel. Stainless steel has higher low-temperature stability and is more reliable as the shell 3. At the same time, the expansion coefficients of stainless steel and pure aluminum are quite different whether in the room temperature range or the extremely low temperature range, which is conducive to improving the response speed of the thermal switch.

[0070] According to an embodiment of the present invention, Figure 5 The second adjusting portion 21 includes a second end cap 211 and a second sleeve 212. The second end cap 211 is connected to the driving portion 22. The second sleeve 212 is sleeved on the outside of the second end cap 211 and is threadedly connected to the housing 3 to drive the second end cap 211 to reciprocate in the vertical direction by rotation.

[0071] In this embodiment, the second end cap 211 is used to connect to the driving unit 22 and contact the second target. Therefore, it is mounted to the housing 3 via the second sleeve 212 to prevent heat transfer along the housing 3 and affect the opening and closing of the thermal switch. The second sleeve 212 can be fixedly connected to the second end cap 211 by welding or interference fit, and then connected to the housing 3 via a simple and reliable threaded connection. By rotating the second end cap 211, the second heat-conducting member 2 can be moved vertically as a whole.

[0072] For example, when the drive portion 22 is made of pure aluminum, the second end cap 211 and the second joint portion 23 are preferably made of oxygen-free copper, which can effectively improve thermal conductivity. The second sleeve 212 is preferably made of stainless steel. On the one hand, it can form a good fit with the housing 3, reduce wear and prolong service life, and on the other hand, it can prevent heat from the second end cap 211 from leaking into the housing 3.

[0073] In some optional embodiments, the second end cap 211 and the driving portion 22 are connected by bolts, and the driving portion 22 and the second engaging portion 23 are connected in a plug-in manner.

[0074] In an exemplary embodiment, Figure 5 As shown, the first adjustment portion 11 includes a first end cap 111 and a first sleeve 112. The first end cap 111 is connected to the first elastic member 12, and the first sleeve 112 is sleeved on the outside of the first end cap 111 and is threadedly connected to the housing 3, and is driven by rotation to reciprocate the first end cap 111 in the vertical direction.

[0075] In this embodiment, the first end cap 111 is used to connect to the first elastic member 12 and contact the first target object. Therefore, it is mounted to the housing 3 via the first sleeve 112 to prevent heat from being transferred along the housing 3 and affecting the opening and closing of the thermal switch. The first sleeve 112 can be fixedly connected to the first end cap 111 by welding or interference fit, and then connected to the housing 3 via a simple and reliable threaded connection. This allows the first end cap 111 to move vertically while being rotated, thereby adjusting the deformation of the first elastic member 12.

[0076] According to an embodiment of the present invention, the first end cap 111 , the first elastic member 12 and the first joint portion 13 are made of the same material, and the thermal conductivity of the same material is greater than that of the housing 3 .

[0077] In this embodiment, after passing through the second heat-conducting member 2, the heat from the second target object must be transferred to the first target object through the first end cap 111, the first elastic member 12, and the first joint 13 in sequence. Therefore, a material with a high thermal conductivity, particularly a thermal conductivity greater than that of the housing 3, is required to achieve efficient heat transfer. Furthermore, due to the special structure of the first elastic member 12, all three components are made of the same material to reduce connection difficulty.

[0078] Preferably, the first end cap 111, the first elastic member 12, and the first joint 13 are all made of oxygen-free copper. Since the first end cap 111 also needs to be configured with a first sleeve 112 and threadedly connected to the housing 3, the diameter of the first end cap 111 is limited. Therefore, the first end cap 111 and the first elastic member 12 are preferably integrally molded, and the first elastic member 12 is a generally S-shaped spring sheet made of oxygen-free copper. The diameter of the first joint 13 is not limited, so the first joint 13 and the first elastic member 12 can be integrally molded. Alternatively, a connecting seat can be provided at the lower end of the first elastic member 12 to connect to the first joint 13, or no connection is provided, so that the connecting seat and the first joint 13 are pressed against each other.

[0079] According to an embodiment of the present invention, the first end cap 111 is configured as a hollow cylindrical structure, and the first thermal conductor 1 further includes an upper stopper 14, a lower stopper 15, and a second elastic member 16. The upper stopper 14 seals the upper end of the first end cap 111, and the lower stopper 15 is disposed within the first end cap 111, extending from the lower end of the first end cap 111 and pressing against the first joint 13. The second elastic member 16 has its ends pressing against the upper stopper 14 and the lower stopper 15, respectively, and is configured to be in a compressed state to increase the contact pressure between the first joint 13 and the second thermal conductor 2.

[0080] In this embodiment, the upper limit member 14 is fixedly connected to the first end cap 111, a portion of the lower limit member 15 is located within the first end cap 111, and the other portion passes through the lower end of the first end cap 111 and the center of the first elastic member 12 to press against the first joint portion 13. When the first end cap 111 is rotated to adjust the deformation of the first elastic member 12, for example, when the first end cap 111 moves downward, the deformation of the first elastic member 12 increases, and the upper limit member 14 moves downward accordingly, while the lower limit member 15 always presses against the first joint portion 13, thereby increasing the deformation of the second elastic member 16 and increasing the pressure of the lower limit member 15 on the first joint portion 13.

[0081] In some optional embodiments, such as Figure 5 As shown, the lower limit member 15 includes a fastening bolt 151, a limit platform 152 and a main body 153. The main body 153 passes through the interior of the first end cap 111 and penetrates the first elastic member 12 to press against the first joint portion 13. The limit platform 152 is arranged on the main body 153 and is used to limit the second elastic member 16. The limit platform 152 is constructed as an annular disc. The fastening bolt 151 passes through the annular disc and is threadedly connected to the main body 153 to fix the limit platform 152 to the main body 153.

[0082] In some other embodiments, a limiting protrusion is further provided at the lower end of the first end cap 111 to limit the limiting platform 152 from falling out of the first end cap 111 .

[0083] Figure 7 It is a schematic diagram of the dilution refrigeration equipment provided by the present invention.

[0084] An exemplary embodiment of the present invention further provides a dilution refrigeration device, such as Figure 7 As shown, the system includes a pre-cooling unit 4, a dilution cooling unit 5, and a thermal switch 6 such as in any of the above-described embodiments. The pre-cooling unit 4 includes a cold head 41 and a pre-cooling plate 42. The cold head 41 is adapted to cool the pre-cooling plate 42, which serves as a first target. The dilution cooling unit 5 includes a dilution cooling core 51 and a core-stage plate 52, which serves as a second target. The dilution cooling core 51 is configured to cool the core-stage plate 52 in response to the temperature of the core-stage plate 52 being below a target temperature. The thermal switch 6 is disposed between the pre-cooling plate 42 and the core-stage plate 52.

[0085] In this embodiment, after the dilution refrigeration system is activated, the pre-cooling unit 4 begins cooling, specifically the cold head 41 cools the pre-cooling cold plate 42. At this point, the temperature of the core-stage cold plate 52 is higher than the target temperature, and the thermal switch 6 opens. Heat from the core-stage cold plate 52 is transferred to the pre-cooling cold plate 42, which is then removed by the cold head 41. When the temperature of the core-stage cold plate 52 drops below the target temperature, the dilution refrigeration core 51 begins to cool the core-stage cold plate 52 further, and the thermal switch 6 closes to prevent heat from the pre-cooling cold plate 42 from being transferred back to the core-stage cold plate 52.

[0086] In some other embodiments, the pre-cooling unit 4 includes a primary cold head and a secondary cold head. The primary cold head has higher power but a limited minimum temperature (approximately 40K-45K) that can be achieved. The secondary cold head has lower power but a lower minimum temperature (approximately 3K-4K) than the primary cold head. Accordingly, two pre-cooling cold plates 42 are provided, and heat conduction between adjacent pre-cooling cold plates 42 is also possible via a thermal switch 6. The core-stage cold plate 52 includes an evaporation chamber cold plate and a mixing chamber cold plate, and heat conduction between these two cold plates is also possible via a thermal switch 6. In other words, multiple stages of cold plates are arranged in the dilution refrigeration device, and heat conduction or thermal isolation can be achieved between adjacent stages via a thermal switch 6. By adjusting the target temperature of the thermal switch 6, multiple thermal switches 6 with different target temperatures can be selectively opened or closed to match different modes or stages of the dilution refrigeration device, thereby achieving rapid temperature reduction in the dilution refrigeration device.

[0087] It will be understood by those skilled in the art that the features described in the various embodiments of the present invention may be combined and / or coupled in various ways, even if such combinations or couplings are not explicitly described in the present invention. In particular, the features described in the various embodiments of the present invention may be combined and / or coupled in various ways without departing from the spirit and teachings of the present invention. All such combinations and / or couplings fall within the scope of the present invention.

[0088] The above describes embodiments of the present invention. However, these embodiments are for illustrative purposes only and are not intended to limit the scope of the present invention. Although each embodiment has been described separately above, this does not mean that the measures in each embodiment cannot be advantageously used in combination. Without departing from the scope of the present invention, those skilled in the art may make various substitutions and modifications, which should all fall within the scope of the present invention.

Claims

1. A thermal switch, characterized in that: include: The shell is constructed as a tubular structure with two ends open; The first heat conducting member is in contact with the first target object and includes: a first adjusting portion, mounted at the upper opening of the housing; a first elastic member, located in the housing and connected to the first adjusting portion; a first joint portion connected to the first adjusting portion via the first elastic member; a second heat conducting member, mounted at the lower opening of the housing and in contact with a second target object, wherein the second target object presses against the first joint portion to conduct heat to the first heat conducting member in response to the second target object being at a higher temperature than a target, and wherein the second target object is separated from the first joint portion to be thermally isolated from the first heat conducting member in response to the second target object being at a lower temperature than the target; The first elastic member is configured such that an amount of deformation generated when the second heat conducting member is in the first state can be adjusted by the first adjusting portion to change a contact pressure between the second heat conducting member and the first engaging portion.

2. The thermal switch according to claim 1, wherein: A limiting boss is formed on the inner wall of the shell, which is suitable for preventing the first engaging portion from moving toward the second heat conducting member under the drive of the first elastic member.

3. The thermal switch according to claim 2, characterized in that The second heat conducting member is further configured to reciprocate in a vertical direction so that the second heat conducting member switches between a first state and a second state in response to different target temperatures.

4. The thermal switch according to claim 3, characterized in that The first heat-conducting member and the second heat-conducting member are arranged sequentially in a vertical direction, the second heat-conducting member forms heat conduction with the first heat-conducting member at a first position, the distance between the first position and the limiting boss is a preset spacing, and the second heat-conducting member is configured to move back and forth in the vertical direction to change the size of the preset spacing, thereby adjusting the contact time between the second heat-conducting member and the first joint portion.

5. The thermal switch according to claim 4, characterized in that The second heat conducting member comprises: a second engaging portion, adapted to press against or disengage from the first engaging portion; a driving portion, one end of which is connected to the second engaging portion and configured to expand or contract in response to temperature changes to drive the second engaging portion to move in a vertical direction; The second adjusting portion is rotatably mounted on the housing and connected to the other end of the driving portion, and is suitable for adjusting the preset distance.

6. The thermal switch according to claim 5, characterized in that The second adjusting unit includes: a second end cap connected to the driving portion; The second sleeve is sleeved on the outside of the second end cap and is threadedly connected to the housing so as to drive the second end cap to reciprocate in the vertical direction through rotation.

7. The thermal switch according to claim 1, wherein: The first adjustment unit includes: a first end cap connected to the first elastic member; The first sleeve is sleeved on the outside of the first end cap and is threadedly connected to the housing so as to drive the first end cap to reciprocate in the vertical direction through rotation.

8. The thermal switch according to claim 7, characterized in that The first end cap is configured as a hollow cylindrical structure, and the first heat conducting member further comprises: an upper limit member, sealing the upper end of the first end cap; a lower stopper, disposed in the first end cap, extending from a lower end of the first end cap and pressing against the first joint portion; The second elastic member has two ends respectively pressed against the upper limit member and the lower limit member, and is configured to be in a compressed state to increase the contact pressure between the first joint portion and the second heat conducting member.

9. The thermal switch according to claim 7, characterized in that The first end cap, the first elastic member and the first joint portion are made of the same material, and the thermal conductivity thereof is greater than the thermal conductivity of the shell.

10. A dilution refrigeration device, characterized in that: include: A pre-cooling unit, comprising a cold head and a pre-cooling stage cold plate, wherein the cold head is adapted to cool the pre-cooling stage cold plate, and the pre-cooling stage cold plate serves as a first target object; a dilution refrigeration unit comprising a dilution refrigeration core and a core-stage cold plate, wherein the core-stage cold plate serves as a second target, and wherein the dilution refrigeration core is configured to reduce the temperature of the core-stage cold plate in response to the core-stage cold plate being below a target temperature; The thermal switch according to any one of claims 1 to 9 is arranged between the pre-cooling stage cold plate and the core stage cold plate.

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