Multi-stage heat exchanger, mixing chamber and dilution refrigerator

Abstract

The utility model relates to the field of extremely low temperature refrigeration technology provides a multistage heat exchanger, including intermediate axle, the intermediate axle is sleeved with a plurality of heat exchange components, heat exchange component includes the base plate of screwing on the intermediate axle, the both surfaces of base plate all are formed with the heat exchange layer, the outside of intermediate axle is provided with the same number of thread section as heat exchange component along the axial direction in proper order, every thread section is screwed the base plate of corresponding heat exchange component. Therefore, the utility model passes through the interposing of multiple heat exchange components on the intermediate axle, the thickness of every heat exchange layer is controllable, has higher heat exchange efficiency, the thickness sum of each heat exchange layer is bigger, makes the heat exchanger have enough heat exchange capacity. Balanced the relationship of the heat exchange efficiency of single heat exchange layer and the total heat exchange, broke through the restriction of the upper limit of heat exchange layer thickness to heat exchange capacity. The multistage heat exchange components adopt the screwing mode and are sleeved on the intermediate axle, and the utility model discloses convenient dismounting and replacement. The utility model further provides a mixing chamber and dilution refrigerator.

Description

Technical Field

[0001] This utility model belongs to the field of cryogenic refrigeration technology, and particularly relates to a multi-stage heat exchanger, a mixing chamber, and a dilution refrigeration machine. Background Technology

[0002] Heat exchangers in dilution refrigerators typically utilize the large specific surface area of ​​nano-silver powder to achieve efficient heat exchange. To reduce the impact of piezoresistive thermal resistance on heat exchange efficiency at extremely low temperatures, it is usually necessary to increase the thickness of the silver powder layer. However, an excessively thick silver powder layer can negatively affect heat exchange performance, creating a bottleneck.

[0003] As disclosed in Chinese Patent CN118757932A, the silver powder layer of existing heat exchangers is usually columnar or disc-shaped, which is inconvenient to replace after installation.

[0004] In conclusion, the existing technology obviously has inconveniences and defects in practical use, so it is necessary to improve it. Utility Model Content

[0005] To address the aforementioned shortcomings, this utility model mainly provides a multi-stage heat exchanger, solving the technical problems of the upper limit of the silver powder layer thickness in existing heat exchangers and the inconvenience of replacement.

[0006] To address the aforementioned problems, this utility model provides a multi-stage heat exchanger, comprising an intermediate shaft on which multiple heat exchange components are sleeved; each heat exchange component includes a substrate threaded onto the intermediate shaft; heat exchange layers are formed on both surfaces of the substrate; the heat exchange layers are sintered layers of nano-metal powder. The outer surface of the intermediate shaft is provided with threaded segments in sequence along the axial direction, the same number as the number of heat exchange components, and each threaded segment is screwed onto the base plate of the corresponding heat exchange component.

[0007] According to the multi-stage heat exchanger of this utility model, a clearance hole is provided at the center of the substrate, and a sleeve is fixedly fitted in the clearance hole, with the sleeve screwed with the corresponding threaded section.

[0008] According to the multi-stage heat exchanger of this utility model, the diameter of each threaded segment on the intermediate shaft increases sequentially along the axial direction, and a stop surface is formed at the junction of two adjacent threaded segments.

[0009] According to the multi-stage heat exchanger of this utility model, a plurality of protrusions are distributed on the surface of the substrate.

[0010] According to the multi-stage heat exchanger of this utility model, the surface of the substrate is plated with a metal plating layer of the same metal element as the heat exchange layer.

[0011] According to the multi-stage heat exchanger of this utility model, the intermediate shaft is made of oxygen-free copper and the surface of the intermediate shaft is gold-plated.

[0012] According to the multi-stage heat exchanger of this utility model, from top to bottom, the thickness of the heat exchange layer of each heat exchange component on the intermediate shaft increases sequentially; the thickness difference of the heat exchange layer of two adjacent heat exchange components does not exceed 3mm.

[0013] A mixing chamber includes a base, on which an inner cover and an outer cover are fixedly mounted; at least one of the multi-stage heat exchangers is fixedly connected within the base area enclosed by the inner cover; a through hole is provided on the side wall of the inner cover near the base, and a flow channel is formed between the inner cover and the outer cover.

[0014] According to the mixing chamber of this utility model, the intermediate shaft is provided with 3-5 stages of heat exchange components.

[0015] A dilution refrigeration unit having the aforementioned mixing chamber.

[0016] In summary, the multi-stage heat exchanger of this invention, by connecting multiple heat exchange components through an intermediate shaft, with each heat exchange component having two heat exchange layers on its base plate; the thickness of each heat exchange layer is controllable, resulting in high heat exchange efficiency; and the large sum of the thicknesses of all heat exchange layers provides sufficient heat exchange capacity. It balances the relationship between the heat exchange efficiency of a single heat exchange layer and the overall heat exchange volume, overcoming the limitation of heat exchange capacity imposed by the upper limit of heat exchange layer thickness. Each stage of the heat exchange components is screwed onto the intermediate shaft for easy disassembly and replacement. This invention also provides a mixing chamber, including a base, on which at least one multi-stage heat exchanger is fixedly mounted. This invention further provides a dilution refrigerator with the aforementioned mixing chamber. Attached Figure Description

[0017] Figure 1 This is a schematic diagram of the structure of the multi-stage heat exchanger of this utility model; Figure 2 This is a schematic diagram of the heat exchange component of this utility model; Figure 3 This is a schematic diagram of the structure of one embodiment of the substrate of this utility model; Figure 4 This is a schematic diagram of the structure of the intermediate shaft of this utility model; Figure 5 yes Figure 1 A cross-sectional structural diagram of a multi-stage heat exchanger in a medium; Figure 6 This is a schematic diagram of the structure of an embodiment of the mixing chamber of this utility model; Figure 7 This is a schematic diagram of the structure of an embodiment of the mixing chamber of this utility model; Figure 8 yes Figure 7 A cross-sectional view of the mixing chamber. In the figure: 1-intermediate shaft, 11-threaded section, 12-stop surface; 2-base plate, 21-sleeve, 22-heat exchange layer, 23-protrusion, 24-displacement hole; 3-base, 4-outer cover, 41-inner cover, 411-through hole; 42-flow channel. Detailed Implementation

[0018] See Figure 1 This utility model provides a multi-stage heat exchanger, including an intermediate shaft 1, on which multiple heat exchange components are sleeved; see also Figure 2 The heat exchange assembly includes a base plate 2 threaded onto the intermediate shaft 1; a heat exchange layer 22 is formed on both surfaces of the base plate 2. Optionally, the heat exchange layer 22 is a sintered layer of nano-metal powder, which has a large specific surface area and good heat exchange effect. Preferably, the heat exchange layer 32 is formed by sintering silver powder.

[0019] See Figure 4 The outer surface of the intermediate shaft 1 is provided with threaded segments 11 in sequence along the axial direction, the same number as the number of heat exchange components. Each threaded segment 11 corresponds to the base plate 2 of a heat exchange component being screwed on. In this invention, the threaded segments 11 are not connected to each other, so that there is a gap between the heat exchange layers 22 of two adjacent heat exchange components; thus, each heat exchange component can exchange heat independently.

[0020] This invention connects multiple heat exchange components to an intermediate shaft 1. Each heat exchange component has two heat exchange layers 22 on its base plate 2. The thickness of each heat exchange layer 22 is controllable, resulting in high heat exchange efficiency. The total thickness of all heat exchange layers 22 is relatively large, giving the heat exchanger sufficient heat exchange capacity. This design balances the relationship between the heat exchange efficiency of a single heat exchange layer 22 and the overall heat exchange volume, overcoming the limitation of the upper limit of the heat exchange layer 22 thickness on heat exchange capacity. Each heat exchange component is screwed onto the intermediate shaft 1 for easy disassembly and replacement.

[0021] Optionally, a clearance hole 24 is provided at the center of the substrate 2, and the clearance hole 24 is threadedly fitted with the threaded segment 11; As one embodiment, a sleeve 21 is fixedly connected in the clearance hole 24, and the sleeve 21 is screwed with the corresponding threaded section 11; the base plate 2 is relatively thin, and by screwing the sleeve 21 with the threaded section 11, the screwing area with the intermediate shaft 1 is increased, thereby improving stability and heat exchange efficiency.

[0022] Optionally, the sleeve 21 is fixed to the substrate 2 by brazing.

[0023] Combination Figure 5In one embodiment, the diameter of each threaded segment 11 on the intermediate shaft 1 increases sequentially along the axial direction, and a stop surface 12 is formed at the junction of two adjacent threaded segments 11. After the base plate 2 or sleeve 21 of each heat exchange component is screwed into place, it can form a surface contact fit with the stop surface 12 of the corresponding layer, defining the position of the heat exchange component on the intermediate shaft 1, which facilitates the assembly operation of the multi-stage heat exchanger. The position of each stop surface 12 on the intermediate shaft 1 matches the overall thickness of the heat exchange component, and there is a definite gap between two adjacent heat exchange components after assembly, resulting in high assembly accuracy.

[0024] Preferably, the intermediate shaft 1 of this invention is made of oxygen-free copper, which has good thermal conductivity. Furthermore, the surface of the intermediate shaft 1 is gold-plated to improve thermal conductivity.

[0025] See Figure 3 As one embodiment, a plurality of bumps 23 are distributed on the surface of the substrate 2 to increase the contact area with the heat exchange layer 22, improve the adhesion between the two, and improve the thermal conductivity.

[0026] As one embodiment, the surface of the substrate 2 is plated with a metal layer of the same element as the heat exchange layer 22; this improves the bonding strength between the substrate 2 and the heat exchange layer 22.

[0027] As one embodiment, multiple reinforcing ribs are raised on the surface of the substrate 2, and the multiple reinforcing ribs divide the surface of the substrate 2 into multiple grid areas; thereby increasing the bonding strength with the heat exchange layer 22.

[0028] As one embodiment, the thickness of the heat exchange layer 22 of each heat exchange component on the intermediate shaft 1 increases sequentially from top to bottom; this better overcomes the influence of the Carpitza thermal resistance at different locations. Furthermore, the thickness difference of the heat exchange layer 22 between adjacent heat exchange components does not exceed 3 mm.

[0029] See Figure 6-8 The present invention also provides a mixing chamber, including a base 3, on which an inner cover 41 and an outer cover 4 sleeved outside the inner cover 41 are fixedly mounted; at least one of the multi-stage heat exchangers is fixedly connected in the area of ​​the base 3 surrounded by the inner cover 41; a through hole 411 is opened on the side wall of the inner cover 41 near the base 3, and a flow channel 42 is formed between the inner cover 41 and the outer cover 4. Optionally, the intermediate shaft 1 of the multi-stage heat exchanger is inserted and fixed on the base 3, and the two are fixed together by brazing; it has high stability and good thermal conductivity.

[0030] In one implementation, a mixture of helium-3 and helium-4 is filled into the internal space of the inner casing 41, forming a concentrated phase and a dilute phase. Liquid helium-3 is added from the top of the inner casing 41 and enters the flow channel 42 through the through hole 411, and is then extracted in gaseous form.

[0031] In one embodiment, a multi-stage heat exchanger is fixed on the base 3, and 3-5 stages of heat exchange components are provided on the intermediate shaft 1; thus, a multi-stage heat exchange is formed from top to bottom. Those skilled in the art can adapt the diameter relationship between the base plate 2, the inner cover 41, and the outer cover 4 to achieve efficient heat exchange.

[0032] As one embodiment, multiple multi-stage heat exchangers are uniformly fixed on the base 3. Optionally, 1-3 layers of heat exchange components can be installed on each intermediate shaft 1. This is suitable for scenarios with large-area, low-height heat exchange spaces.

[0033] The multi-stage heat exchanger of this invention can occupy a larger space in the mixing chamber, reduce the amount of helium-3 used, and reduce the cost of refrigeration operation.

[0034] This utility model also provides a dilution refrigeration machine having the aforementioned mixing chamber.

[0035] In summary, this invention provides a multi-stage heat exchanger by connecting multiple heat exchange components along an intermediate shaft. Each heat exchange component has two heat exchange layers on its base plate. The thickness of each heat exchange layer is controllable, resulting in high heat exchange efficiency. The total thickness of all heat exchange layers is relatively large, giving the heat exchanger sufficient heat exchange capacity. It balances the relationship between the heat exchange efficiency of a single heat exchange layer and the overall heat exchange volume, overcoming the limitation of heat exchange capacity imposed by the upper limit of heat exchange layer thickness. Each stage of the heat exchange components is screwed onto the intermediate shaft for easy disassembly and replacement. This invention also provides a mixing chamber, including a base on which at least one multi-stage heat exchanger is fixedly mounted. This invention further provides a dilution refrigerator with the aforementioned mixing chamber.

[0036] Of course, there may be other embodiments of this utility model. Without departing from the spirit and essence of this utility model, those skilled in the art can make various corresponding changes and modifications based on this utility model, but these corresponding changes and modifications should all fall within the protection scope of the appended claims of this utility model.

Claims

1. A multi-stage heat exchanger, characterized in that, The device includes an intermediate shaft on which multiple heat exchange components are sleeved; each heat exchange component includes a substrate threaded onto the intermediate shaft; a heat exchange layer is formed on both surfaces of the substrate; the heat exchange layer is a sintered layer of nano-metal powder. The outer surface of the intermediate shaft is provided with threaded segments in sequence along the axial direction, the same number as the number of heat exchange components, and each threaded segment is screwed onto the base plate of the corresponding heat exchange component.

2. The multi-stage heat exchanger as described in claim 1, characterized in that, A clearance hole is provided at the center of the substrate, and a sleeve is fixedly fitted into the clearance hole. The sleeve is screwed with the corresponding threaded section.

3. The multi-stage heat exchanger as described in claim 1, characterized in that, The diameter of each threaded segment on the intermediate shaft increases sequentially along the axial direction, and a stop surface is formed at the junction of two adjacent threaded segments.

4. The multi-stage heat exchanger as described in claim 1, characterized in that, Multiple bumps are distributed on the surface of the substrate.

5. The multi-stage heat exchanger as described in claim 1, characterized in that, The surface of the substrate is plated with a metal plating layer of the same metal element as the heat exchange layer.

6. The multi-stage heat exchanger as described in claim 1, characterized in that, The intermediate shaft is made of oxygen-free copper and its surface is plated with gold.

7. The multi-stage heat exchanger as described in claim 1, characterized in that, From top to bottom, the thickness of the heat exchange layer of each heat exchange component on the intermediate shaft increases sequentially; the thickness difference of the heat exchange layer between two adjacent heat exchange components does not exceed 3mm.

8. A mixing chamber, characterized in that, The device includes a base, on which an inner cover and an outer cover are fixedly mounted; within the base area enclosed by the inner cover, at least one multi-stage heat exchanger as described in any one of claims 1 to 7 is fixedly connected; a through hole is provided on the side wall of the inner cover near the base, and a flow channel is formed between the inner cover and the outer cover.

9. The mixing chamber as claimed in claim 8, characterized in that, The intermediate shaft is equipped with 3-5 stages of heat exchange components.

10. A dilution refrigeration machine, characterized in that, It has a mixing chamber as described in claim 8 or 9.

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