A magnetocaloric module for use in a very low temperature adiabatic demagnetocaloric refrigerator

Abstract

The application discloses a magnetocaloric module for an extremely low temperature adiabatic demagnetization refrigerator, which comprises a magnetocaloric module side pipe shell and a heat conducting device, the magnetocaloric module side pipe shell is internally provided with a cavity, and an opening communicating with the cavity is arranged on the side wall; the heat conducting device comprises a heat conducting component and a heat conducting structure, the heat conducting component comprises multiple layers of heat conducting fins wound into a cylindrical shape, gaps are arranged between each layer of heat conducting fins for accommodating magnetocaloric materials, the heat conducting component axially extends and is mounted in the cavity, and the central axes of each layer of heat conducting fins are coaxial, the heat conducting structure is fixed at both ends of the magnetocaloric module side pipe shell to seal the cavity, and the heat conducting structure is also used for transferring heat outward. The magnetocaloric module is simple and efficient in manufacturing and processing, convenient in installation, efficient in heat transfer, small in cold loss caused by eddy current heating, favorable for reducing the eddy current heating effect, and favorable for achieving a better magnetic shielding effect.

Description

Technical Field

[0001] This invention belongs to the field of cryogenic insulation and demagnetization refrigeration technology, and particularly relates to a magnetothermal module used in cryogenic insulation and demagnetization refrigeration machines. Background Technology

[0002] Adiabatic demagnetizing refrigeration, as the mainstream refrigeration technology in cryogenic refrigeration, plays an important role in basic and cutting-edge scientific research fields such as condensed matter physics, space exploration, and quantum technology. It has outstanding advantages such as wide temperature coverage, high intrinsic efficiency, and independence from gravity and scarce working fluids.

[0003] The fundamental principle of cryogenic adiabatic demagnetization refrigeration is the magnetocaloric effect of magnetocaloric materials. The magnetocaloric effect is an inherent property of magnetocaloric materials; it refers to the physical phenomenon where the magnetic order of a magnetocaloric material changes in a changing magnetic field, causing a change in magnetic entropy, which in turn leads to an increase or decrease in the material's temperature. The main structure of an adiabatic demagnetization refrigeration system includes a superconducting magnet, magnetic shielding, a magnetocaloric module, a thermal switch, a heat sink, and the devices being cooled.

[0004] The magnetocaloric module is the core component of the adiabatic demagnetizing refrigerator and the source of cooling in cryogenic adiabatic demagnetizing refrigeration technology. It mainly consists of magnetocaloric materials and a heat transfer structure. In cryogenic adiabatic demagnetizing refrigeration technology, the refrigeration cycle generally adopts a reverse Carnot cycle, mainly including the following four thermodynamic processes: adiabatic excitation, isothermal excitation, adiabatic demagnetization, and isothermal demagnetization. During the excitation process, the magnetocaloric module needs to conduct and release the heat it generates to the heat sink. During the demagnetization process, the magnetocaloric module needs to transfer the generated cooling to the heat load. Therefore, the magnetocaloric module needs to have good thermal conductivity. In the cryogenic region, the magnetocaloric material in the magnetocaloric module generally uses paramagnetic salt crystals containing coordinated water, including FAA (Fe(SO4)2NH4·12H2O, iron ammonia vanadium), CPA (CrK(SO4)2·12H2O, chromium potassium vanadium), and CMN (Ce2Mg3(NO3)). 12 Examples of paramagnetic salt crystals containing coordinating water include 24H₂O and magnesium cerium nitrate. However, these paramagnetic salt crystals have poor thermal conductivity in extremely low temperatures below 1 K. The heat / cold generated by these paramagnetic salt crystals alone is insufficient to transfer the generated heat / cold to the heat sink / cooled device within a limited time. Therefore, the magnetocaloric module requires a thermally conductive structure to enhance its own heat conduction.

[0005] In related technologies, paramagnetic salts are often grown on a bundle of metal wires (usually copper or gold) or cut from a single thick copper rod into multiple thin copper rods to enhance the internal heat transfer of the magnetocaloric module. While this does improve the internal heat transfer, it also introduces new problems. For magnetocaloric modules using metal wires, the heat exchange requires welding both ends of a large number of metal wires (typically over 500) to an end heat-conducting structure (such as copper rods). However, the welded sections have poor thermal contact at extremely low temperatures, resulting in a significant temperature difference between the wire bundle and the copper rods. This leads to a loss of cooling capacity in the adiabatic demagnetizing refrigerator. Furthermore, the metal wire bundles in the magnetocaloric module require manual threading of each wire, ensuring they are as parallel and non-contact as possible. The manufacturing process for the wire bundles is complex and labor-intensive. While wire-cut magnetocaloric module heat transfer structures eliminate the need for additional metal wire insertion, the wire-cutting process limits the diameter of the thin copper rods, resulting in a larger volumetric ratio than the metal wires. Within the limited volume of the magnetocaloric module, this excessive volumetric ratio of the heat transfer structure encroaches on the volume of the magnetocaloric material, reducing its quantity and consequently decreasing the maximum total cooling capacity of the refrigerator. Furthermore, the relatively large diameter of the wire-cut copper rods leads to a more pronounced eddy current heating effect in a changing magnetic field, further contributing to cooling capacity loss in the adiabatic demagnetizing refrigerator. Therefore, in extremely low-temperature regions, it is necessary to develop a simple and efficient heat transfer structure suitable for use in magnetocaloric modules of cryogenic adiabatic demagnetizing refrigerators to address these issues. Summary of the Invention

[0006] To address at least one of the problems mentioned in the background art, the present invention aims to provide a magnetothermal module for use in an ultra-low temperature adiabatic demagnetizing refrigerator.

[0007] This invention is achieved through the following technical solution:

[0008] A magnetocaloric module for use in a cryogenic adiabatic demagnetizing refrigerator, comprising:

[0009] A magnetothermal module side shell, wherein a cavity is provided inside the magnetothermal module side shell and an opening communicating with the cavity is provided on the side wall;

[0010] A heat-conducting device includes a heat-conducting component and a heat-conducting structure. The heat-conducting component includes multiple layers of heat-conducting fins wound into a cylindrical shape. There are gaps between each layer of heat-conducting fins to accommodate magnetocaloric material. The heat-conducting component is axially extended and installed in the cavity, and the central axis of each layer of heat-conducting fins is coaxial. The heat-conducting structure is fixed to both ends of the side shell of the magnetocaloric module to seal the cavity. The heat-conducting structure is also used to transfer heat to the outside.

[0011] Optionally, the heat-conducting component further includes support fins, which are square-shaped sheets. Multiple layers of heat-conducting fins are vertically inserted into the support fins such that the central axis of each layer of heat-conducting fins extends in the height direction of the support fins.

[0012] Optionally, each layer of heat-conducting fins includes multiple arc-shaped fins, each arc-shaped fin is fixed to the supporting fin to form a cylindrical heat-conducting fin, and fin slits are provided between each arc-shaped fin.

[0013] Optionally, the support fins can be integral or segmented. When the support fins are integral, they are square-shaped pieces, with the central axis of each heat-conducting fin coinciding with the vertical center bisector of the support fins. When the support fins are segmented, they are two square-shaped pieces of equal area, with the outermost edge of each support fin terminating at the outermost heat-conducting fin and the innermost edge terminating at the innermost heat-conducting fin.

[0014] Optionally, the support fins may be one or more.

[0015] Optionally, both the heat-conducting fins and the support fins are provided with multiple small holes.

[0016] Optionally, the heat-conducting structure includes an end cap and a heat-conducting rod, one end of the end cap covering the cavity, and the other end fixing the heat-conducting rod so that the heat-conducting rod extends in a direction away from the end cap.

[0017] Optionally, the end cap that fits into the cavity has multiple slots that are adapted to the end of the heat-conducting component, and the end cap also has multiple radially extending end cap slits.

[0018] Optionally, the heat-conducting structure further includes one or more heat-conducting plates, which are fixed to the end of the end cap on which the heat-conducting rod is mounted and are in contact with the heat-conducting rod.

[0019] Optionally, the opening is provided in two parts, which are used as the inlet and outlet for growing paramagnetic salt crystals, respectively.

[0020] The beneficial effects of this invention are as follows: The magnetocaloric module for cryogenic demagnetizing refrigerators of this invention solves the problems of high processing difficulty (complex processing and high precision requirements), high labor costs, and large cold loss in the heat transfer technology of existing magnetocaloric modules (significant influence of welding thermal resistance at extremely low temperatures, and significant eddy current heating due to the large cross-section of the thin copper rod obtained by wire cutting). It proposes a structure that is simple to manufacture, highly efficient in heat transfer, and minimizes cold loss in the refrigerator. The beneficial effects achieved are: The magnetocaloric module for cryogenic demagnetizing refrigerators of this invention, by adopting a split or integrated fin structure, makes the manufacturing and processing of the heat conduction structure of the magnetocaloric module simpler and more efficient, and the installation more convenient, with lower labor costs for installation. Compared with existing magnetocaloric module heat conduction structures, the heat conduction structure of the magnetocaloric module in this invention, due to the use of fins and slots in the internal heat conduction structure and the fit between the upper and lower end caps, is more reliable and efficient. Furthermore, the magnetocaloric module in this invention employs a split or integrated finned heat-conducting structure, with end caps featuring slots and slits, resulting in more efficient heat transfer and less cooling loss due to eddy current heating. The end heat-conducting component of this invention can be assembled from multiple fan-shaped bodies or triangular prisms to form a cylinder or polygonal prism, making the structure more compact, significantly saving installation space and reducing installation difficulty. Simultaneously, the smaller radial cross-section of the assembled heat transfer structure helps reduce the eddy current heating effect, further enhancing the magnetic shielding effect. Attached Figure Description

[0021] To more clearly illustrate the specific embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0022] Figure 1 This is a schematic diagram of the structure of an ultra-low temperature thermal insulation demagnetizing refrigerator according to an embodiment of the present invention;

[0023] Figure 2 This is an overall structural diagram of a magnetocaloric module in a cryogenic thermal demagnetizing refrigerator according to an embodiment of the present invention.

[0024] Figure 3 This is a schematic diagram of the structure of a heat-conducting component for a magnetocalor module in an ultra-low temperature adiabatic demagnetizing refrigerator according to an embodiment of the present invention, wherein (a) is a perspective view and (b) is a top view;

[0025] Figure 4This is a schematic diagram of the structure of a heat-conducting component for a magnetocalor module in an ultra-low temperature adiabatic demagnetizing refrigerator according to another embodiment of the present invention, wherein (a) is a perspective view and (b) is a top view;

[0026] Figure 5 This is a schematic diagram of the heat-conducting structure of a magnetocaloric module in an ultra-low temperature thermal demagnetizing refrigerator according to an embodiment of the present invention.

[0027] Figure 6 This is a schematic diagram of the end cap of a magnetocaloric module in an ultra-low temperature thermal demagnetizing refrigerator according to an embodiment of the present invention, wherein (a) is a perspective view and (b) is a bottom view;

[0028] Figure 7 This is a schematic diagram of the end cap of a magnetocaloric module in a cryogenic adiabatic demagnetizing refrigerator according to another embodiment of the present invention, wherein (a) is a perspective view and (b) is a bottom view;

[0029] Among them, 1. heat-conducting rod; 2. magnetic shield; 3. superconducting magnet; 5. end cap; 6. side shell of magnetothermal module; 7. heat-conducting component; 71. support fin; 72. heat-conducting fin; 73. fin slit; 81. slot; 83. end cap slit; 9. heat-conducting sheet. Detailed Implementation

[0030] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The components of the embodiments of the present invention described and shown in the accompanying drawings can generally be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0031] In the description of the embodiments of the present invention, it should be understood that the terms "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They 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 device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on the embodiments of the present invention.

[0032] The following is for reference Figure 1-7The magnetocaloric module used in an ultra-low temperature adiabatic demagnetizing refrigerator according to embodiments of the present invention will be described in detail.

[0033] like Figure 2-7 As shown, the magnetocaloric module for an ultra-low temperature adiabatic demagnetizing refrigerator provided according to an embodiment of the present invention includes a magnetocaloric module side shell 6 and a heat-conducting device. The magnetocaloric module side shell 6 has a cavity inside, and an opening communicating with the cavity is provided on the side wall. The heat-conducting device includes a heat-conducting component 7 and a heat-conducting structure. The heat-conducting component 7 includes multiple layers of heat-conducting fins 72 wound into a cylindrical shape. A gap is provided between each layer of heat-conducting fins 72 for accommodating magnetocaloric material. The heat-conducting component 7 is axially extended and installed in the cavity, and the central axis of each layer of heat-conducting fins 72 is coaxial. The heat-conducting structure is fixed to both ends of the magnetocaloric module side shell 6 to seal the cavity. The heat-conducting structure is also used to transfer heat to the outside.

[0034] Preferably, the opening has two parts, which are used as the inlet and outlet for growing paramagnetic salt crystals, respectively.

[0035] like Figure 3 and 4 As shown, in one embodiment, the heat-conducting component further includes a support fin 71, which is a square-shaped sheet. Multiple layers of heat-conducting fins 72 are vertically disposed on the support fin 71 such that the central axis of each layer of heat-conducting fins 72 extends in the height direction of the support fin 71.

[0036] like Figure 3 and 4 As shown, in one embodiment, each layer of heat-conducting fins 72 includes multiple arc-shaped fins, each arc-shaped fin is fixed on the supporting fin 71 to form a cylindrical heat-conducting fin 72, and a fin slit 73 is provided between each arc-shaped fin.

[0037] Optionally, the support fin 71 can be integral or segmented. When the support fin 71 is integral, it is a single square sheet, with the central axis of each heat-conducting fin 72 coinciding with the vertical center bisector of the support fin 71. When the support fin 71 is segmented, it is two square sheets of equal area, with the outermost edge of each support fin 71 terminating at the outermost heat-conducting fin 72 and the innermost edge terminating at the innermost heat-conducting fin 72. In this embodiment, there are one or more support fins 71.

[0038] like Figure 3 and 4 As shown, in one embodiment, both the heat-conducting fins 72 and the supporting fins 71 are provided with a plurality of small holes.

[0039] It should be noted that the finned heat-conducting structure component 7 is made of a metal material with high thermal conductivity, such as copper or other metals with high thermal conductivity. Since the magnetic field inside the magnetocaloric module is mainly axial, to reduce eddy current heat generation in the magnetic field, the finned heat-conducting component 7 is made of a thin metal sheet rolled up, with a thickness of 0.01–2 mm, and arranged axially. A certain number of small holes can be processed on the metal sheet using laser drilling, machining, or other methods. The shape of the holes is not limited and can be polygonal or circular, etc. This allows for an increase in the amount of paramagnetic salt crystals used in the magnetocaloric module without affecting the thermal conductivity of the finned heat-conducting structure, thereby increasing the cooling capacity of the cryogenic adiabatic demagnetizing refrigerator. Furthermore, the holes in the metal sheet facilitate the flow of the solution between different metal sheets during the growth of paramagnetic salt crystals, promoting crystal growth. The finned heat-conducting component 7 can be a split-type or an integrated-type finned heat-conducting component.

[0040] like Figure 4 The diagram shows a split-type finned heat conduction assembly 7. It can be understood that the split-type finned heat conduction assembly 7 includes split-type support fins 71, split-type heat conduction fins 72, and split-type fin slots 73. A certain number of split-type fin slots 73 in the finned heat conduction assembly 7 are used to reduce the effective communication area of ​​the heat conduction structure of the magnetocaloric module in the radial direction, thereby reducing the effective magnetic flux through the heat conduction structure in the magnetocaloric module and reducing eddy current heat generation. The split-type support fins 71 are used to support multiple heat conduction fins, making the heat conduction structure more complete and easier to operate. Depending on actual needs, the number of support fins and slots in the split-type finned heat conduction assembly 7 can be 1, 2, 3, 4, ...

[0041] It is understandable that the different supporting fins 71 in the split-type finned heat conduction assembly 7 are separate and not interconnected. Therefore, the split-type finned heat conduction assembly can be divided into 1 to N identical structures for batch processing, resulting in high processing efficiency.

[0042] like Figure 3 The image shows an integrated finned heat conduction assembly 7. It can be understood that the integrated finned heat conduction assembly 7 includes integrated support fins 71, integrated heat conduction fins 72, and integrated fin slots 73. Similar to a split-type finned heat conduction assembly, the integrated finned heat conduction assembly also includes a certain number of integrated fin slots 73 and integrated support fins 71. The difference is that the different integrated support fins 71 in the integrated finned heat conduction assembly are interconnected, sharing a common intersecting axis. Therefore, it can be understood that the integrated finned heat conduction assembly is a single, integral structure, making its installation simple and convenient.

[0043] Similarly, it can be understood that in an integrated finned heat conduction assembly, the number of integrated support fins and integrated fin cuts can be 1, 2, 3, 4, ... depending on the actual needs.

[0044] like Figure 5 As shown, in one embodiment, the heat-conducting structure includes an end cap 5 and a heat-conducting rod 1. One end of the end cap 5 covers the cavity, and the other end fixes the heat-conducting rod 1 so that the heat-conducting rod 1 extends in a direction away from the end cap 5. It should be noted that the end cap 5 can also be provided separately. In this embodiment, the end cap 5 and the heat-conducting rod 1 are collectively referred to as a heat-conducting structure for ease of description.

[0045] like Figure 6 and 7 As shown, preferably, the end cap 5 has a plurality of slots 81 adapted to the end of the heat-conducting component 7 at one end that covers the cavity, and the end cap 5 also has a plurality of radially extending end cap slits 83.

[0046] like Figure 7 The image shows the end cap of the magnetocaloric module corresponding to the split-type finned heat conduction assembly. It can be understood that when the finned heat conduction assembly 7 adopts a split structure, the upper and lower end caps 5 in the magnetocaloric module must also adopt the upper and lower end caps corresponding to the split-type magnetocaloric module. When the upper and lower end caps 5 of the magnetocaloric module are made of a high thermal conductivity metal, they serve as the outer shell of the magnetocaloric module, the support for the finned heat conduction assembly 7, and the medium for heat or cold transfer.

[0047] It is understood that the end cap 5 of the magnetothermal module corresponding to the split-fin heat conduction assembly 7 includes a slot 81 for the split-fin support fins, a slot 81 for the split-conducting fins, and a slit 83 for the split end cap. In the magnetothermal module, to utilize the supporting function of the end cap 5, a slot 81 for the split-fin support fins can be opened on one side of the end cap. The structure of the slot changes according to the variation of the split-fin heat conduction assembly. Therefore, when installing the magnetothermal module, the slots 81 for the split-fin support or heat conduction fins on the upper and lower end caps 5 of the magnetothermal module are directly assembled with the split-fin heat conduction assembly, making the installation very simple and convenient.

[0048] It is understandable that the magnetic field around the upper and lower end caps 5 of the magnetocaloric module is relatively strong. Therefore, in order to reduce the eddy current heat generation of the metal under the magnetic field, the upper and lower end caps 5 of the magnetocaloric module can be slit, such as the split end cap slit 83 in the end cap 5 of the magnetocaloric module. In the slit treatment, there can be 1 to N split end cap slits 83. When the end cap is finally sealed, the split end cap slits 83 on the end cap of the magnetocaloric module can be sealed by adhesive (e.g., epoxy resin 2850), so that the interior is a closed cavity, which facilitates the growth of paramagnetic salt crystals later.

[0049] like Figure 6 The image shows the end cap of the magnetothermal module corresponding to the integrated finned heat conduction assembly. It can be understood that when the finned heat conduction assembly 7 is integrated, the upper and lower end caps 5 in the magnetothermal module must also be the upper and lower end caps of the magnetothermal module corresponding to the integrated finned assembly. When the upper and lower end caps 5 of the magnetothermal module are made of a high thermal conductivity metal (such as copper), the end cap 5 of the magnetothermal module corresponding to the integrated finned heat conduction assembly 7 includes a slot 81 for the integrated supporting fins 71, a slot 81 for the integrated heat conduction fins, and a slit 83 for the integrated end cap. Similarly, the slots and slits have the same function as those in the end caps of the magnetothermal module corresponding to the separate fins, facilitating installation and reducing eddy current heat generation.

[0050] like Figure 5 As shown, in one embodiment, the heat-conducting structure further includes one or more heat-conducting sheets 9, which are fixed to the end of the end cap 5 on which the heat-conducting rod 1 is mounted and are in contact with the heat-conducting rod 1.

[0051] For example, such as Figure 5 The diagram shown is a schematic of the heat conduction structure of a magnetocaloric module when it has a heat-conducting plate.

[0052] It is understandable that when low thermal conductivity metals or low thermal conductivity non-metals are used as the materials for the upper and lower end covers 5 of the magnetic thermal module, such as low thermal conductivity metal stainless steel or low thermal conductivity non-metal glass fiber G10, the upper and lower end covers 5 of the magnetic thermal module only serve as the support for the finned heat conduction assembly 7 and the outer shell of the magnetic thermal module. Therefore, the ends of the magnetic thermal module need to be combined with other end heat conduction plates 9 in order to conduct the heat and cold energy transferred from the finned heat conduction assembly 7 to the outside.

[0053] Understandably, in this example, to facilitate the assembly of the end structure and the transfer of heat and cold from the magnetocaloric module, the slots on the end cap 5, made of low thermal conductivity metal or low thermal conductivity non-metal, differ. They are through slots, directly penetrating the upper and lower surfaces of the end cap, and the number and position of the slots vary depending on the finned heat-conducting assembly. For example, the slots on the end cap 5 corresponding to the split-type finned heat-conducting assembly and the integrated finned heat-conducting assembly are somewhat different; the slots for the split-type assembly do not converge, while the slots for the integrated assembly converge.

[0054] It should be noted that in end caps 5 made of low thermal conductivity metals such as stainless steel, slits are also required to reduce eddy current heat generation in the magnetic field. Furthermore, to ensure structural integrity, the slits must be intermittent. However, in end caps 5 made of low thermal conductivity non-metals such as glass fiber G10, since glass fiber is non-conductive and there is no eddy current heating phenomenon, slits are not required.

[0055] It is understandable that, to enhance heat conduction, the heat-conducting plate 9 is made of a metal with high thermal conductivity, such as copper or gold, which are common metal materials. To reduce the generation of eddy current heat in the end heat-conducting plate 9, the heat-conducting plate 9 can adopt a small copper block structure. Simultaneously, the number of heat-conducting plates 9 can be 1 to N, and the heat-conducting plate 9 can be a polygonal copper block, such as a fan-shaped / triangular / rectangular shape, etc., whose sides contact the supporting fins 71 in the finned heat-conducting assembly 7 for heat conduction, thereby transferring the heat in the heat-conducting fins to the outside. The heat-conducting rod 1 can be a columnar body, such as a cylinder, a fan-shaped body, or a triangular prism, etc., with a fan-shaped / triangular prism being preferred. Therefore, when the heat-conducting plate and the heat-conducting rod are combined, multiple fan-shaped / triangular prisms can be assembled together to form a cylinder / polygonal prism, which makes the end heat-conducting structure more compact, greatly saving installation space and installation difficulty. Furthermore, because the radial cross-section of the heat transfer structure formed by the assembly is small, it helps to reduce the eddy current heating effect and is more conducive to achieving a better magnetic shielding effect.

[0056] For details, please refer to Figure 2 This is an external view of the magnetothermal module provided in an embodiment of the present invention.

[0057] It is understandable that in the ultra-low temperature region magnetic thermal module, the upper and lower end covers 5 and the magnetic thermal module side shell 6 together constitute the outer shell of the magnetic thermal module. The magnetic thermal module side shell 6 is generally made of a metal or non-metal with low thermal conductivity to reduce eddy current heat generation in the magnetic field. It is preferably made of stainless steel (a low thermal conductivity metal) or glass fiber G10 (a non-metallic material). The upper and lower end covers 5 in the magnetic thermal module have the same structure; both high and low thermal conductivity metals or non-metals can be used, but their corresponding end cover structures differ. Copper or gold is preferred for high thermal conductivity metals, stainless steel for low thermal conductivity metals, and glass fiber G10 for low thermal conductivity non-metals.

[0058] It is understood that the outer shell of the magnetocaloric module is mainly used for growing paramagnetic salt crystals in the extremely low temperature region. However, due to the poor thermal conductivity of paramagnetic salt crystals in the extremely low temperature region, the magnetocaloric module often employs a certain heat-conducting structure inside to enhance heat transfer, so that the heat or cold generated by the paramagnetic salt crystal can be transferred away. In this embodiment of the invention, the heat-conducting component 7 inside the magnetocaloric module adopts a finned heat-conducting structure, which can easily and efficiently transfer the heat or cold generated by the paramagnetic salt, and is simple to process and has low labor input costs.

[0059] It is understandable that two small openings are made on the circumferential side of the magnetothermal module shell 6, which are used as the feed inlet and discharge outlet when growing paramagnetic salt crystals, respectively.

[0060] It should be noted that you should refer to [link / reference]. Figure 1This is a radial cross-sectional view of an ultra-low temperature adiabatic demagnetizing refrigerator to which the magnetocaloric module of this embodiment can be applied. It mainly includes a heat-conducting rod 1, a magnetic shield 2, a superconducting magnet 3, an end cap 5 of the magnetocaloric module, a side shell 6 of the magnetocaloric module, and a heat-conducting component 7. The magnetocaloric module, from top to bottom, includes the upper heat-conducting rod 1, the upper end cap 5 of the magnetocaloric module, the side shell 6 of the magnetocaloric module, the heat-conducting component 7, the lower end cap 5 of the magnetocaloric module, and the lower heat-conducting rod 1.

[0061] It is understood that the superconducting magnet 3, the magnetic shield 2, and the magnetocaloric module are coaxially arranged in the adiabatic demagnetizing refrigerator. Spatially, from the inside out, they are the magnetocaloric module, the superconducting magnet 3, and the magnetic shield 2. The magnetic shield 2 is bolted to the outside of the superconducting magnet 3, while the magnetocaloric module is suspended at the center inside the superconducting magnet 3 by multiple Kevlar wires. One end of each Kevlar wire is connected to the upper and lower end faces of the superconducting magnet 3, and the other end is connected to the upper and lower heat-conducting rods 1 (not shown in the diagram). The upper and lower heat-conducting rods 1 are used to transfer the heat / cold generated in the magnetocaloric module to the outside. Therefore, their material can be a metal or non-metal with high thermal conductivity, such as copper rods, gold-plated copper rods, or gold rods. Furthermore, to reduce the eddy current heat generated in the magnetic field by the upper and lower heat-conducting rods 1, their diameter is smaller than that of the upper and lower end caps 5 of the magnetocaloric module.

[0062] Therefore, the magnetothermal module in the ultra-low temperature adiabatic demagnetizing refrigerator provided in this invention, compared with the existing magnetothermal module heat conduction structure, adopts a split / integrated fin structure, making the manufacturing and processing of the magnetothermal module heat conduction structure simpler and more efficient, the installation more convenient, and the labor input cost for installation lower. Compared with the existing magnetothermal module heat conduction structure, the magnetothermal module in this invention, due to the use of fins and slots in the internal heat conduction structure and the fit between the upper and lower end caps, has a more reliable and efficient fit. In addition, the magnetothermal module in this invention adopts a split / integrated fin structure, and the end cap has features such as slots and slits, making heat transfer more efficient and reducing the cold loss caused by eddy current heating. On the end cap of this invention, multiple fan-shaped bodies / triangular prisms can be assembled together to form a cylinder / polygonal prism, which makes the structure of the end heat conduction component more compact, greatly saving installation space and installation difficulty. At the same time, because the radial cross section of the heat transfer structure formed by the assembly is smaller, it is beneficial to reduce the eddy current heating effect and achieve a better magnetic shielding effect. The magnetothermal module in this invention is a magnetothermal module structure used in ultra-low temperature adiabatic demagnetizing refrigerators with superior performance.

[0063] In the description of this invention, the terms "first," "second," "another," and "yet another" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of embodiments of this invention, "a plurality of" means two or more, unless otherwise explicitly specified.

[0064] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "connected" and "linked" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances. Furthermore, in the description of this invention, unless otherwise stated, "a plurality of" means two or more.

[0065] Although embodiments of the invention have been shown and described, those skilled in the art will understand that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the claims and their equivalents.

Claims

1. A magnetocaloric module for use in an ultra-low temperature adiabatic demagnetizing refrigerator, characterized in that, include: A magnetothermal module side shell, wherein a cavity is provided inside the magnetothermal module side shell and an opening communicating with the cavity is provided on the side wall; A heat-conducting device, comprising a heat-conducting component and a heat-conducting structure, wherein the heat-conducting component comprises multiple layers of heat-conducting fins wound into a cylindrical shape, with gaps between each layer of heat-conducting fins for accommodating magnetocaloric material, the heat-conducting component is axially extended and installed in the cavity, and the central axis of each layer of heat-conducting fins is coaxial, the heat-conducting structure is fixed to both ends of the side shell of the magnetocaloric module to seal the cavity, and the heat-conducting structure is also used to transfer heat to the outside; The heat-conducting component also includes support fins, which are square-shaped sheets. Multiple layers of heat-conducting fins are vertically inserted into the support fins, such that the central axis of each layer of heat-conducting fins extends in the height direction of the support fins. Each layer of heat-conducting fins includes multiple arc-shaped fins. Each arc-shaped fin is fixed to the supporting fin to form a cylindrical heat-conducting fin. There are fin slits between each arc-shaped fin. The support fins can be integral or segmented. When the support fins are integral, they are square-shaped pieces, with the central axis of each heat-conducting fin coinciding with the vertical center bisector of the support fin. When the support fins are segmented, they are two square-shaped pieces of equal area, with the outermost edge of each support fin terminating at the outermost heat-conducting fin and the innermost edge terminating at the innermost heat-conducting fin.

2. The magnetocaloric module for use in an ultra-low temperature thermal demagnetizing refrigerator according to claim 1, characterized in that, The support fins may be one or more.

3. The magnetocaloric module for an ultra-low temperature thermal demagnetizing refrigerator according to claim 1, characterized in that, Both the heat-conducting fins and the support fins have multiple small holes.

4. The magnetocaloric module for use in an ultra-low temperature thermal demagnetizing refrigerator according to claim 1, characterized in that, The heat-conducting structure includes an end cap and a heat-conducting rod. One end of the end cap covers the cavity, and the other end fixes the heat-conducting rod so that the heat-conducting rod extends in a direction away from the end cap.

5. A magnetocaloric module for use in an ultra-low temperature thermal demagnetizing refrigerator according to claim 4, characterized in that, The end cap, which fits into the cavity, has multiple slots that fit the end of the heat-conducting component, and the end cap also has multiple radially extending end cap slits.

6. The magnetocaloric module for use in an ultra-low temperature thermal demagnetizing refrigerator according to claim 5, characterized in that, The heat-conducting structure further includes one or more heat-conducting plates, which are fixed to the end of the end cap on which the heat-conducting rod is mounted and are in contact with the heat-conducting rod.

7. A magnetocaloric module for use in an ultra-low temperature thermal demagnetizing refrigerator according to claim 1, characterized in that, The opening has two parts, which are used as the feed inlet and the discharge outlet for growing paramagnetic salt crystals, respectively.

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