Heat exchange unit, heat exchanger and dilution refrigerator

Abstract

The utility model provides a heat exchange single body, a heat exchanger and a dilution refrigerating machine. The heat exchange single body comprises a heat conduction piece, two cover bodies and a sealing piece. The heat conduction piece is provided with a first surface and a second surface which deviate from each other, and containing grooves are formed in the first surface and the second surface. The two cover bodies are arranged on the first surface and the second surface respectively so as to seal the containing groove. The sealing piece is arranged between the cover body and the first surface and the second surface and is suitable for deforming under extrusion of the cover body so as to seal a gap between the cover body and the first surface or the second surface. Wherein a first cavity is defined between the cover body and the containing groove formed by the first surface, a second cavity is defined between the cover body and the containing groove formed by the second surface, a flowing 3He solution is contained in the first cavity, and a flowing mixed solution of the 3He solution and a 4He solution is contained in the second cavity, so that the 3He solution and the mixed solution exchange heat through the heat conduction piece.

Description

Technical Field

[0001] At least one embodiment of the present utility model relates to the field of cryogenic technology, and more specifically, to a heat exchange monomer, a heat exchanger, and a dilution refrigerator. Background Art

[0002] A dilution refrigerator is a cryogenic refrigeration device based on the principle of dilution refrigeration, which is mainly used in research and experiments in the fields of physics, materials science, biology, etc. With the continuous development of science and technology, the demand for low-temperature environments in various experimental research activities is getting higher and higher. Due to its excellent performance and broad application prospects, the dilution refrigerator has become an important research direction in the field of cryogenic technology.

[0003] In currently widely used dilution refrigerators, mainly 3 He and 4 He mixed working fluids are used for refrigeration. Its main principle is as follows: when the 3 He and 4 He mixture is in the temperature range below 0.86K, it will separate into two phases. The upper layer is the concentrated phase, and the main component is 3 He, that is, 3 He solution. The lower layer is the dilute phase, and the main component is the mixture of 3 He and 4 He, in which 3 He accounts for about 6.4% - 6.6%. By extracting 3 He in the dilute phase and condensing 3 He vapor into 3 He solution and then flowing it back into the concentrated phase, and then passing through the phase interface where the concentrated phase and the dilute phase are separated to form dilution refrigeration. And the 3 He solution formed by condensation often has more heat. Directly flowing back into the concentrated phase may affect the refrigeration efficiency. Therefore, it is necessary to flow through a heat exchanger for heat exchange before returning to the concentrated phase.

[0004] In the related art, for the heat exchanger of the dilution refrigerator, welding is often used for assembly and sealing, which is convenient for operation and has low cost. However, due to the different linear shrinkage rates of the solder material and the heat exchanger body material in the extremely low-temperature environment, the structure at the welding point is fragile and the stress is uneven during the assembly process of the heat exchanger, and at the same time, the problem of seal failure is extremely likely to occur. And due to the extremely low temperature, the Kapitza thermal resistance generated at the heat transfer interface between different materials has a more significant impact. In order to improve the heat transfer efficiency, sintered materials are usually filled inside the heat exchanger to increase the heat transfer area, but the high temperature generated by welding may cause the sintered materials to be melted and damaged. Therefore, how to provide a heat exchanger and a dilution refrigerator that can have better sealing performance under extremely low-temperature conditions has become an urgent technical problem to be solved. Summary of the Utility Model

[0005] In view of this, the present utility model provides a heat exchange monomer, a heat exchanger and a dilution refrigerator, which use the deformation of a seal to seal the heat exchange monomer, avoiding leakage of 3 the He solution at a relatively low temperature and 3 the He and 4 He mixture. Through the heat exchange of the heat exchanger, the refrigeration efficiency of the dilution refrigerator is also effectively improved.

[0006] To achieve the above object, as the present utility model provides a heat exchange monomer, including: a heat conducting member having a first surface and a second surface facing away from each other, and accommodation grooves are provided in both the first surface and the second surface; two cover bodies are respectively provided on the first surface and the second surface to seal the accommodation grooves; a seal is provided between the cover body and the first surface and the second surface, and is adapted to deform under the extrusion of the cover body to seal the gap between the cover body and the first surface or the second surface; wherein, a first cavity is defined between the cover body and the accommodation groove formed by the first surface, and a second cavity is defined between the cover body and the accommodation groove formed by the second surface. There is flowing 3 He solution in the first cavity, and there is flowing 3 He solution and 4 a mixture of He solution in the second cavity, so that the 3 He solution and the mixture exchange heat through the heat conducting member.

[0007] In an exemplary embodiment, the heat conducting member is configured as a disc shape, and the accommodation grooves formed by the first surface and the second surface are both configured as annular shapes.

[0008] In an exemplary embodiment, the heat conducting member includes a cylindrical portion provided in the middle of the heat conducting member and an annular portion coaxially provided outside the cylindrical portion. A partition portion extending in the radial direction of the accommodation groove is provided between the cylindrical portion and the annular portion, so that the accommodation groove forms a C-shaped flow channel.

[0009] In an exemplary embodiment, a pipe body is provided on the cover body and serves as the liquid inlet end of the accommodation groove, and a liquid outlet is provided on the bottom surface of the heat conducting member facing the cover body and serves as the liquid outlet end of the accommodation groove; wherein, in the orthographic projection in the axial direction of the heat conducting member, the liquid inlet end and the liquid outlet end are located at two ends of the flow channel away from each other.

[0010] In an exemplary embodiment, it further includes a filling body, and the filling body is provided in the accommodation groove to increase the 3 heat exchange area of the He solution or the mixture.

[0011] In an exemplary embodiment, the above-mentioned filler includes a sintered body made of nano silver powder.

[0012] The present utility model also provides a heat exchanger, which includes a heat exchange monomer as described in any of the above embodiments.

[0013] In an exemplary embodiment, it includes a plurality of the above-mentioned heat exchange monomers, and the plurality of the above-mentioned heat exchange monomers are stacked.

[0014] In an exemplary embodiment, the first cavities of adjacent above-mentioned heat exchange monomers are communicated, and the second cavities of adjacent above-mentioned heat exchange monomers are communicated; wherein, the communicated first cavities are used as the hot side of the heat exchanger, and the communicated second cavities are used as the cold side of the heat exchanger.

[0015] The present utility model also provides a dilution refrigerator, which includes a heat exchanger as described in any of the above embodiments.

[0016] In an exemplary embodiment, it further includes: a mixing chamber, in which there is stored a 3 He enriched phase located in the upper layer and a 3 He dilution phase located in the lower layer, and the 3 He enriched phase is configured to compensate 3 He to the 3 He dilution phase in response to a decrease in the concentration of 3 He in the 3 He dilution phase and absorb surrounding heat for refrigeration; an evaporation part, which is communicated with the mixing chamber through the above-mentioned heat exchanger to store at least a part of the 3 He dilution phase, and the evaporation part is configured to evaporate and extract 3 He from the 3 He dilution phase, and after condensation, form a 3 He solution and flow back to the 3 He enriched phase to form a cycle of dilution refrigeration with the above-mentioned mixing chamber; wherein, the above-mentioned heat exchanger includes a hot side and a cold side, the hot side is suitable for the 3 He solution to flow back to the 3 He enriched phase, and the cold side is suitable for communicating with the 3 He dilution phase in the mixing chamber and the evaporation part to perform heat exchange with the hot side.

[0017] In an exemplary embodiment, the above-mentioned evaporation part includes: an evaporation chamber, which is communicated with the mixing chamber through the cold side to store at least a part of 3 He dilution phase; a vacuum pump, which, in response to the evaporation chamber being within a preset temperature range, evacuates the 3In the He dilution phase 3 He is extracted in the form of steam; a throttling circuit, which communicates with the mixing chamber through the above-mentioned hot side and is configured to 3 throttle and cool the He steam to form 3 a He solution.

[0018] In an exemplary embodiment, it further includes a cold plate, fixedly connected to the outside of the mixing chamber and suitable for placing cooling objects.

[0019] For the heat exchange monomer, heat exchanger and dilution refrigerator provided by the present utility model, inside the heat exchange monomer 3 the He solution and the mixed liquid exchange heat through the heat conducting member, and the sealing member can seal the heat exchange monomer after being compressed and deformed at normal temperature. Compared with the traditional welding seal, it has good low-temperature sealing performance, avoiding the leakage problem caused by the difference in linear shrinkage rate between the solder and the material of the heat exchange monomer at low temperature, and the operation process is simple. In addition, by setting a plurality of heat exchange monomers to form a heat exchanger, the heat exchange effect is improved, and it is avoided that 3 the He solution carries too much heat into the mixing chamber, and the refrigeration efficiency of the dilution refrigerator is effectively improved. Description of the Drawings

[0020] Through the following description of the embodiments of the present utility model with reference to the drawings, the above and other objects, features and advantages of the present utility model will become clearer. In the drawings:

[0021] Figure 1 is a sectional view of a heat exchange monomer provided by the present utility model;

[0022] Figure 2 is Figure 1 a three-dimensional structure diagram of the heat conducting member in the shown exemplary embodiment;

[0023] Figure 3 is a three-dimensional schematic diagram of a dilution refrigerator provided by the present utility model.

[0024] In the above-mentioned drawings, the meanings of the reference numerals are specifically as follows:

[0025] 1. Heat exchange monomer;

[0026] 11. Heat conducting member;

[0027] 111. Cylindrical part;

[0028] 112. Annular part;

[0029] 113. Partition part;

[0030] 114. Liquid outlet;

[0031] 12. Cover body;

[0032] 121. Pipe body;

[0033] 13. Seal;

[0034] 14. Filling body;

[0035] 2. Mixing chamber;

[0036] 3. Evaporation chamber;

[0037] 4. Vacuum pump;

[0038] 5. Throttle circuit;

[0039] 6. Cold plate. Detailed implementation manners

[0040] To make the objectives, technical solutions and advantages of the present utility model clearer and more understandable, the following further elaborates on the present utility model in detail with reference to specific embodiments and the accompanying drawings.

[0041] The terms used herein are merely for describing specific embodiments and are not intended to limit the present utility model. The terms "including", "comprising", etc. used herein indicate the presence of the described features, steps, operations and / or components, but do not exclude the presence or addition of one or more other features, steps, operations or components.

[0042] 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.

[0043] In the case of using expressions such as "at least one of A, B, and C, etc.", generally, it should be interpreted according to 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 not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C. In the case of using expressions such as "at least one of A, B, or C, etc.", generally, it should be interpreted according to the meaning commonly understood by those skilled in the art. For example, "a system having at least one of A, B, or C" should include, but not be limited to, a system having only A, only B, only C, having A and B, having A and C, having B and C, and / or having A, B, and C.

[0044] It should also be noted that the directional terms mentioned in the embodiments, such as "upper", "lower", "front", "rear", "left", "right", etc., are only for reference to the directions in the drawings and are not used to limit the protection scope of the present invention. Throughout the drawings, the same elements are represented by the same or similar reference numerals. When it may cause confusion in the understanding of the present invention, the conventional structures or configurations will be omitted.

[0045] Figure 1 is a cross-sectional view of a heat exchange monomer provided by the present invention, Figure 2 is Figure 1 a three-dimensional structural diagram of the heat conducting member in the exemplary embodiment shown.

[0046] An exemplary embodiment of the present invention provides a heat exchange monomer, as Figure 1 shown, including a heat conducting member 11, two cover bodies 12 and a sealing member 13. The heat conducting member 11 has a first surface and a second surface facing away from each other, and accommodation grooves are provided in both the first surface and the second surface. The two cover bodies 12 are respectively disposed on the first surface and the second surface to seal the accommodation grooves. The sealing member 13 is disposed between the cover body 12 and the first surface and the second surface, and is adapted to deform under the extrusion of the cover body 12 to seal the gap between the cover body 12 and the first surface or the second surface. Among them, a first cavity is defined between the cover body 12 and the accommodation groove formed by the first surface, and a second cavity is defined between the cover body 12 and the accommodation groove formed by the second surface. There is flowing 3 He solution in the first cavity, and there is flowing 3 He solution and 4 a mixed solution of He solution in the second cavity, so that 3 the He solution and the mixed solution exchange heat through the heat conducting member 11.

[0047] In such an implementation manner, there is flowing 3 He solution and 3 He solution and 4 a mixed solution of He solution inside the heat exchange monomer, and heat exchange is achieved between them through the heat conducting member 11. To improve the sealing performance of the heat exchange monomer and avoid liquid leakage, a sealing member 13 is provided between the cover body 12 and the first surface and the second surface to seal the first cavity and the second cavity after being deformed under pressure. Compared with the traditional method of directly welding the cover body 12 and the heat conducting member 11, the leakage problem caused by excessive shrinkage of the solder at low temperature is avoided, and the low-temperature sealing performance is effectively improved.

[0048] According to an embodiment of the present disclosure, the two cover bodies 12 are respectively a first cover body and a second cover body. The first cover body is correspondingly installed on the first surface to define the first cavity for supplying 3The He solution flows. The second cover body is correspondingly installed on the second surface to define a second cavity for the flow of the mixed liquid (i.e., 3 the He solution and 4 the mixed liquid of the He solution), so that 3 the He solution and the mixed liquid can exchange heat through the heat conducting member 11.

[0049] Specifically, the material of the seal 13 is preferably selected to have good ductility, so as to deform under the extrusion of the cover body 12 and the heat conducting member 11 and fill the gap between the cover body 12 and the first surface or the second surface. At the same time, since the temperature of the He solution and the mixed liquid is extremely low, about several tens of millikelvins, when the dilution refrigeration cycle operates normally, the seal 13 also needs to have good low-temperature sealing performance, so as to realize the sealing of 3 the He solution and the mixed liquid. 3 the He solution and the mixed liquid.

[0050] In the embodiment of the present disclosure, the cover body 12 is connected to the first surface and the second surface of the heat conducting member 11 by bolts, and the bolts are tightened to apply pressure to the seal 13. The seal 13 is preferably indium wire, which is laid on the first surface and the second surface, but is not limited thereto.

[0051] In an exemplary embodiment, as Figure 2 shown, the heat conducting member 11 is configured in a disc shape, and the accommodation grooves formed by the first surface and the second surface are both configured in an annular shape.

[0052] In such an embodiment, by configuring the heat conducting member 11 in a disc shape and setting the accommodation groove in an annular shape, the flow resistance when the He solution and the mixed liquid flow can be reduced, so as to ensure the circulation flow rate and refrigeration power of 3He while realizing heat exchange. 3 the He solution and the mixed liquid flow, so as to ensure the circulation flow rate and refrigeration power of 3He while realizing heat exchange.

[0053] In some other embodiments, the heat conducting member 11 is made of, but not limited to, oxygen-free copper to have a relatively high thermal conductivity.

[0054] According to the embodiment of the present disclosure, as Figure 2 shown, the heat conducting member 11 includes a cylindrical portion 111 provided in the middle of the heat conducting member 11 and an annular portion 112 coaxially provided outside the cylindrical portion 111. A partition portion 113 extending in the radial direction of the accommodation groove is provided between the cylindrical portion 111 and the annular portion 112, so as to form a C-shaped flow channel in the accommodation groove.

[0055] In such an embodiment, the heights of the cylindrical portion 111, the annular portion 112 and the partition portion 113 are the same, and after the cover body 12 is installed on the heat conducting member 11, they can all be attached to the cover body 12 to enclose a C-shaped flow channel to extend 3Flow paths of He solution and the mixture

[0056] Furthermore, with reference to Figure 1 and Figure 2 , a liquid inlet for the accommodating groove is provided on the cover body 12 and communicated with the pipe body 121. A liquid outlet 114 is provided on the bottom surface of the heat conducting member 11 facing the cover body 12, serving as the liquid outlet of the accommodating groove. Among them, in the orthographic projection in the axial direction of the heat conducting member 11, the liquid inlet and the liquid outlet are located at two opposite ends of the flow channel.

[0057] In such an embodiment, 3 the He solution or the mixture enters the accommodating groove from the pipe body 121, flows along the C-shaped flow channel, and finally flows out from the liquid outlet 114. Since the liquid inlet and the liquid outlet are located at two opposite ends of the flow channel, it can make 3 the flow path of the He solution or the mixture in the accommodating groove the longest, and the heat exchange is more sufficient.

[0058] It should be noted here that taking the first cavity as an example, 3 when the He solution or the mixture flows out from the liquid outlet 114, it will directly flow out of the heat exchange monomer without passing through the second cavity, and the liquid outlet 114 is not communicated with the second cavity.

[0059] In an exemplary embodiment, the heat exchange monomer further includes a filling body 14, which is arranged in the accommodating groove to increase 3 the heat exchange area of the He solution or the mixture.

[0060] In such an embodiment, since 3 the He solution and the mixture have a very low temperature, about 0.86K (Kelvin), when 3 the He solution and the mixture perform heat exchange with the heat conducting member 11, the Kapitza thermal resistance generated at the interface between the solid surface (the surface of the heat conducting member 11) and the liquid helium ( 3 the He solution, the mixture) seriously affects the heat exchange performance. By setting the filling body 14 to increase the interface area, the influence brought by the Kapitza thermal resistance is reduced.

[0061] According to the embodiment of the present disclosure, the filling body 14 includes a sintered body made of nano silver powder. The particle size of the silver powder particles is selected to be 600 - 800 mm, and sintering is performed using a tube-type atmosphere furnace, and the sintering temperature is about 180 degrees Celsius.

[0062] An exemplary embodiment of the present invention further provides a heat exchanger, including at least one heat exchange monomer 1 as in any of the above embodiments.

[0063] According to the embodiment of the present disclosure, the above heat exchanger includes a plurality of heat exchange monomers 1, and the plurality of heat exchange monomers 1 are stacked.

[0064] In such an embodiment, a plurality of heat exchange monomers 1 are arranged in a stacked manner in the vertical direction, and adjacent heat exchange monomers 1 are connected to each other through liquid pipes. Being composed of a plurality of identical heat exchange monomers 1 is beneficial to reducing production costs and manufacturing difficulties.

[0065] It is worth mentioning that the liquid pipe is preferably made of a material with good stiffness and strength to have a certain degree of support, thereby reducing the support requirements during the assembly of the heat exchanger and simplifying the structure of the heat exchanger.

[0066] Exemplarily, in the embodiments of the present disclosure, the liquid pipe is made of brass and is connected to the heat exchange monomer 1 by soldering.

[0067] In an exemplary embodiment, the first cavities of adjacent heat exchange monomers 1 communicate with each other, and the second cavities of adjacent heat exchange monomers 1 communicate with each other. Among them, the connected first cavities are used as the hot side of the heat exchanger, and the connected second cavities are used as the cold side of the heat exchanger.

[0068] In such an embodiment, since the heat exchange monomers 1 are arranged in a stacked manner in the vertical direction, and each heat exchange monomer 1 is provided with a tube body 121 and a liquid outlet 114, therefore, the hot side of the heat exchanger has a relatively high-temperature 3 He solution, which flows through the first cavity of each heat exchange monomer 1 from top to bottom in sequence. The cold side of the heat exchanger has a relatively low-temperature mixed liquid that does not increase significantly in temperature after absorbing heat, and it flows through the second cavity of each heat exchange monomer 1 from bottom to top in sequence. And during the flow process, the 3 He solution on the hot side and the mixed liquid on the cold side exchange heat through the heat conducting member 11.

[0069] Figure 3 It is a three-dimensional schematic diagram of a dilution refrigerator provided by the present utility model.

[0070] An exemplary embodiment of the present utility model further provides a dilution refrigerator, including the heat exchanger in any of the above embodiments.

[0071] According to the embodiments of the present disclosure, as Figure 3 shown, the above-mentioned dilution refrigerator further includes a mixing chamber 2 and an evaporation section. In the mixing chamber 2, there is stored a 3 He enriched phase located in the upper layer and a 3 He diluted phase located in the lower layer. 3 The He enriched phase is configured to respond to 3 in the He diluted phase, 3 when the concentration of He decreases, compensate for 3 the He diluted phase with 3He absorbs the surrounding heat simultaneously for refrigeration. The evaporation section is connected to the mixing chamber 2 through a heat exchanger to store at least a part of 3 the He dilution phase. The evaporation section is configured to 3 evaporate and extract 3 He from the He dilution phase. After condensation, it forms 3 a He solution flow back 3 to the He enrichment phase to form a cycle of dilution refrigeration with the mixing chamber 2. Among them, the heat exchanger includes a cold side and a hot side. The hot side is suitable for 3 the He solution to flow back 3 to the He enrichment phase. The cold side is suitable for connecting the mixing chamber 2 and the 3 He dilution phase in the evaporation section for heat exchange with the hot side.

[0072] In such an embodiment, the mixing chamber 2 stores 3 the He enrichment phase (i.e., 3 the He solution) and 3 the He dilution phase (i.e., 3 the mixture of He and 4 He). The cold side of the heat exchanger connects the mixing chamber 2 and the evaporation section. When the evaporation section reaches the preset temperature range, about 0.6 - 1K. 3 The saturated vapor pressure of He is higher than 4 He, so it is evaporated and extracted separately. At this time, the 3 He concentration in the evaporation section decreases, and the 3 He dilution phase in the mixing chamber 2 will supplement 3 He to the evaporation section through the cold side flow path. The 3 extracted He vapor becomes 3 a He solution after condensation and returns to the 3 He enrichment phase in the mixing chamber 2 through the hot side flow path. At this time, 3 the 3 He concentration in the He enrichment phase is greater than 3 the 3 He concentration in the He dilution phase. Therefore, 3 the 3 He in the He enrichment phase will move towards 3 the He dilution phase. When 3 He passes through the phase interface, it absorbs the surrounding heat, causing the temperature of the mixing chamber 2 to drop, and thus the dilution refrigeration proceeds in a cycle.

[0073] In some other embodiments, the evaporation section further includes an evaporation chamber 3, a vacuum pump 4, and a throttling circuit 5. The evaporation chamber 3 is connected to the mixing chamber 2 through the cold side to store at least a part of 3 the He dilution phase. The vacuum pump 4 responds to the evaporation chamber 3 being within the preset temperature range and evacuates the 3 He dilution phase in the evaporation chamber 3.3 He is withdrawn in the form of steam. The throttling circuit 5 communicates with the mixing chamber 2 through the hot side and is configured to throttle and cool the 3 He steam to form 3 He solution.

[0074] In such an embodiment, one end of the throttling circuit 5 is connected to the vacuum pump 4, and the other end is connected to the hot side of the heat exchanger. It should be noted here that the throttling circuit 5 passes through the evaporation chamber 3 and then is connected to the heat exchanger. Such a setting can make 3 The He solution exchanges heat with the 3 He dilution phase in the evaporation chamber 3, and then enters the hot side to exchange heat with the 3 He dilution phase in the cold side to improve the heat exchange effect.

[0075] In some other embodiments, a secondary heat exchange part is further provided between the evaporation chamber 3 and the heat exchanger, including an inner tube and an outer tube arranged in a spiral manner. Specifically, the 3 He dilution phase on the cold side of the heat exchanger enters the evaporation chamber 3 after flowing through the interlayer between the inner tube and the outer tube, while the 3 He solution flowing out of the throttling circuit 5 flows through the inner tube, exchanges heat with the 3 He dilution phase in the interlayer and then enters the hot side of the heat exchanger.

[0076] According to an embodiment of the present disclosure, the dilution refrigerator further includes a cold plate 6, which is fixedly connected to the outside of the mixing chamber 2 and is suitable for cooling the object in a suitable manner.

[0077] In such an embodiment, the shape of the cold plate 6 includes but is not limited to a circle or a rectangle, and its material includes but is not limited to heat-conducting materials such as copper or oxygen-free copper.

[0078] The heat exchange monomer in the above embodiment is manufactured by, for example, but not limited to, the following method, which includes steps S100 - S500.

[0079] Step S100, process the heat-conducting member 11 and two cover bodies 12.

[0080] Step S200, fill the receiving groove of the heat-conducting member 11 with silver powder, and apply a pressure perpendicular to the bottom of the receiving groove to the silver powder to compact the silver powder;

[0081] Step S300, sinter the silver powder while maintaining the pressure until a sintered body is formed;

[0082] Step S400, lay indium wires on the joint surface between the heat-conducting member 11 and the cover body 12, connect the cover body 12 to the heat-conducting member 11 through a plurality of bolts, and sequentially tighten each bolt so that the cover body 12 and the heat-conducting member 11 squeeze the indium wires to cause the indium wires to deform to seal the gap between the heat-conducting member 11 and the cover body 12.

[0083] Step S500: Detect the leakage of the heat exchange monomer 1, and the qualified standard is that the leakage rate does not exceed 1×10 -10 mbarl / s.

[0084] According to an embodiment of the present disclosure, in step S100, the heat conducting member 11 and the cover 12 are processed using oxygen-free copper.

[0085] It further includes step S110: After processing and forming, use sandpaper to polish to remove surface burrs. After polishing, soak it in a citric acid solution and perform ultrasonic cleaning to remove surface stains.

[0086] Furthermore, it further includes step S120: Polish again using sandpaper. After polishing, put it into an isopropyl alcohol solution and perform ultrasonic cleaning.

[0087] It should be noted here that after obtaining the rough blank by processing with oxygen-free copper, steps S110 - S120 need to be repeatedly executed until there are no obvious oxidation and burr defects on the surface of the workpiece.

[0088] Even further, it further includes S130: After cleaning, perform drying treatment using a vacuum oven. The drying temperature is 80°C, the drying time is not less than 10 hours, and the vacuum degree of the vacuum oven is less than or equal to 0.1 mbar.

[0089] In step S200, the particle size range of the silver powder is 600nm - 800nm. Before filling the silver powder, first lay a layer of coarse silver powder with a diameter of 1μm - 10μm at the bottom of the receiving groove to increase the roughness of the bottom wall of the receiving groove and ensure that the silver powder adheres tightly to the bottom wall of the receiving groove, that is, the surface of the oxygen-free copper. Then fill the silver powder to 2 / 3 of the depth of the receiving groove, and use a metal pressing block and an electric press to compact the silver powder, applying a pressure of about 50 bar.

[0090] More specifically, the shape of the metal pressing block matches the shape of the receiving groove. Before pressing, the metal pressing block is limited by a flange and screws. During the pressing process of the electric press, the pressure is vertically downward and perpendicular to the bottom wall of the receiving groove. At this time, the screws are still in the initial state when they are limited. After pressing is completed, after the metal pressing block moves downward a certain distance, the screws are naturally tightened until they press against the metal pressing block, and then the electric press can be withdrawn.

[0091] To avoid adhesion between the silver powder and the metal pressing block, a polytetrafluoroethylene film or gasket can be set between the metal pressing block and the silver powder.

[0092] In step S300, the metal pressing block, together with the heat conducting member 11 and the silver powder, is fired together. Firing is carried out using a tubular atmosphere furnace, introducing a hydrogen-argon mixture with a pressure of about 200 mbar and a hydrogen content of 5%. The firing temperature is about 180 degrees, and the firing time is about 6 hours.

[0093] Further, it further includes step S310. After firing is completed, remove the metal pressing block, and clean the joint surface of the heat conducting member 11 and the cover body 12 with ethanol or isopropyl alcohol. Prepare indium wires with a diameter of about 1 mm, and remove the surface dust with ethanol or isopropyl alcohol.

[0094] In step S400, first lay indium wires at the joint between the first surface of the heat conducting member 11 and the cover body 12. Use 1-mm indium wires to lay 3 - 5 circles annularly on the joint surface, and then use bolts to connect the cover body 12 to the heat conducting member 11. It should be noted that multiple bolts are circumferentially spaced along the edge of the cover body 12. When connecting, first place the cover body 12 naturally on the indium wires, then insert the bolts, and after natural tightening, use a torque wrench to tighten them in sequence. For example, rotate each bolt 90° each time, and then rotate each bolt 45° each time. The angle of rotation of each bolt each time should be as the same as possible, and keep tightening to improve the uniformity of the applied force and avoid generating air bubbles during the deformation of the indium wires, which may affect the sealing performance.

[0095] Further, it further includes step S410. Lay indium wires at the joint between the second surface of the heat conducting member 11 and another cover body 12. Use 1-mm indium wires to lay 3 - 5 circles annularly on the joint surface, and then use bolts to connect the cover body 12 to the heat conducting member 11. The specific tightening method is the same as that in step S400, and will not be elaborated here too much.

[0096] In step S500, after the leak detection is qualified, the heat exchange monomer 1 is prepared.

[0097] In some other embodiments, it further includes repeating steps S100 - S500 to prepare multiple heat exchange monomers 1. The multiple heat exchange monomers 1 are connected by liquid pipelines. In this embodiment, the liquid pipeline is a brass connecting pipe, which is connected to the heat exchange monomer 1 by soldering to complete the preparation of the heat exchanger and conduct overall leak detection on the heat exchanger.

[0098] The embodiments of the present utility model have been described above. However, these embodiments are only for illustrative purposes and not for limiting the scope of the present utility model. Although the embodiments have been described separately above, this does not mean that the measures in each embodiment cannot be used advantageously in combination. The scope of the present utility model is defined by the appended claims and their equivalents. Without departing from the scope of the present utility model, those skilled in the art can make various substitutions and modifications, and these substitutions and modifications should all fall within the scope of the present utility model.

Claims

1. A heat exchange monomer, characterized in that, Comprising: A heat conducting member (11) having a first surface and a second surface facing away from each other, and receiving grooves are provided in both the first surface and the second surface; Two cover bodies (12) respectively disposed on the first surface and the second surface to seal the receiving grooves; A sealing member (13) disposed between the cover body (12) and the first surface and the second surface, adapted to deform under the extrusion of the cover body (12) to seal the gap between the cover body (12) and the first surface or the second surface; Wherein, a first cavity is defined between the lid body (12) and the receiving groove formed on the first surface, and a second cavity is defined between the lid body (12) and the receiving groove formed on the second surface. A flowing 3 He solution is provided in the first cavity, and a flowing 3 He solution and 4 a mixed solution of He solution are provided in the second cavity, so that the 3 He solution and the mixed solution exchange heat through the heat conducting member (11).

2. The monomer according to claim 1, characterized in that, The heat conducting member (11) is configured in a disc shape, and the receiving grooves formed by the first surface and the second surface are both configured in a ring shape.

3. The monomer according to claim 2, wherein The heat conducting member (11) includes a cylindrical portion (111) disposed in the middle of the heat conducting member (11) and a ring portion (112) coaxially disposed outside the cylindrical portion (111), and a partition portion (113) extending in the radial direction of the receiving groove is provided between the cylindrical portion (111) and the ring portion (112) to form a C-shaped flow channel in the receiving groove.

4. The monomer according to claim 3, characterized in that, A tube body (121) is provided on the cover body (12) and serves as the liquid inlet end of the receiving groove, and a liquid outlet (114) is provided on the bottom surface of the heat conducting member (11) facing the cover body (12) and serves as the liquid outlet end of the receiving groove; Wherein, in the orthographic projection in the axial direction of the heat conducting member (11), the liquid inlet end and the liquid outlet end are located at two ends of the flow channel away from each other.

5. The monomer according to claim 1, characterized in that, It further includes a filler (14) disposed in the accommodation groove to increase the 3 heat exchange area of the He solution or the mixture.

6. The monomer according to claim 5, wherein, The filling body (14) includes a sintered body made of nano silver powder.

7. A heat exchanger, characterized in that, Comprising at least one heat exchange monomer (1) as described in any one of claims 1 to 6.

8. The heat exchanger according to claim 7, characterized in that, Comprising a plurality of the heat exchange monomers (1), and the plurality of heat exchange monomers (1) are stacked.

9. The heat exchanger according to claim 8, wherein, The first cavities of adjacent heat exchange monomers (1) are communicated with each other, and the second cavities of adjacent heat exchange monomers (1) are communicated with each other; Wherein, the communicated first cavities serve as the hot side of the heat exchanger, and the communicated second cavities serve as the cold side of the heat exchanger.

10. A dilution refrigerator, characterized in that, Comprising a heat exchanger as described in any one of claims 7 to 9.

11. The dilution refrigerator according to claim 10, characterized in that, Further comprising: Mixing chamber (2), in which there is stored an 3 He enriched phase in the upper layer and an 3 He diluted phase in the lower layer, the 3 He enriched phase is configured to respond to the 3 decrease in the concentration of 3 He in the 3 He diluted phase by compensating 3 He into the He diluted phase while absorbing surrounding heat for refrigeration; An evaporation section, which is connected to the mixing chamber (2) through the heat exchanger, stores at least a part of the 3 He dilution phase. The evaporation section is configured to 3 evaporate and extract He in the 3 He dilution phase, and after condensation, form 3 a He solution that flows back to the 3 He enrichment phase to form a cycle dilution refrigeration with the mixing chamber (2); wherein, The heat exchanger includes a hot side and a cold side, and the hot side is adapted to 3 the He solution flows back to the 3 He enriched phase, and the cold side is adapted to communicate the mixing chamber (2) and the 3 He dilute phase in the evaporation section to perform heat exchange with the hot side.

12. The dilution refrigerator according to claim 11, wherein, The evaporation part includes: Evaporation chamber (3), which is connected to the mixing chamber (2) through the cold side to store at least a part of 3 He dilution phase; A vacuum pump (4), in response to the evaporation chamber (3) being within a preset temperature range, evacuates the 3 He in the diluted phase of 3 He in the form of vapor from the evaporation chamber (3); A throttling circuit (5), which is communicated with the mixing chamber (2) through the hot side and is configured to 3 throttle and cool down the He vapor to form 3 a He solution.

13. The dilution refrigerator according to claim 12, characterized in that, Further comprising a cold plate (6) fixedly connected to the outside of the mixing chamber (2) and adapted to place a cooling object.

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