Throttle valve provided with purification device and used for dilution refrigerator and manufacturing method

Abstract

The invention relates to a throttling valve provided with a purification device and used for a dilution refrigerator and a manufacturing method, and relates to the technical field of refrigeration and low-temperature engineering, the throttling valve comprises a throttling valve high-pressure end structure, a throttling valve middle-end structure is installed on the throttling valve high-pressure end structure, a throttling valve low-pressure end structure is installed on the throttling valve middle-end structure, and a throttling valve low-pressure end structure is installed on the throttling valve low-pressure end structure. A presser structure is installed in the throttling valve high-pressure end structure in a threaded mode, a copper net filter element is arranged in the throttling valve middle-end structure, and a throttling micropore seat structure is jointly installed in the throttling valve middle-end structure and the throttling valve low-pressure end structure. According to the throttling valve provided with the purification device and used for the dilution refrigerator and the manufacturing method, through integrated design, the structure of the throttling valve is compact, a copper net filter element is arranged in the middle end of the throttling valve seat, pressing and fixing are conducted through a pressing device structure, the integrated design of the purification device and the throttling valve is achieved, and the throttling valve is convenient to use. The size of the device is effectively reduced, and the device can be conveniently used in a dilution coolant with limited space.

Description

Technical Field

[0001] The present invention relates to the technical field of refrigeration and cryogenic engineering, and particularly relates to a throttle valve with a self-purification device for a dilution refrigerator and a manufacturing method thereof. Background Art

[0002] A dilution refrigerator is a key device that can provide an ultra-low temperature environment in the millikelvin (mK) temperature range, and plays an important role in frontier scientific research such as quantum computing, condensed matter physics, materials science, and astronomical detection. As one of the key components of a dilution refrigerator, the performance of the throttle valve directly affects the lowest temperature, cooling capacity, and operating stability of the refrigerator.

[0003] During the operation of a dilution refrigerator, the refrigeration working fluid (usually a helium-3 / helium-4 mixture) may carry tiny solid particles or impurities during the circulation process. If these impurities enter the throttle channel, it is extremely easy to cause blockage of the throttle holes. The diameter of the throttle holes is usually in the micron range. Once blockage occurs, the refrigerator cannot work properly, seriously affecting the experimental process and the service life of the equipment.

[0004] Currently, although some dilution refrigerator systems also consider the purification problem, their purification devices and throttle valves are often designed separately, or the purification structure is simple and the filtering effect is limited. Moreover, in an extremely low temperature environment, the structural design, material selection of the purification device, and the integration method with the throttle valve all have an important impact on the overall performance of the refrigerator. In addition, the processing accuracy, sealing performance of the throttle valve itself, and its reliability at low temperatures are also technical problems that need to be solved urgently. Summary of the Invention

[0005] In view of this, the purpose of the present invention is to provide a throttle valve with a self-purification device for a dilution refrigerator and a manufacturing method thereof, so as to solve the problems of the processing accuracy and sealing performance of the throttle valve, and the structural design and material selection of the purification device in the prior art in an extremely low temperature environment.

[0006] The present invention is achieved through the following technical solutions:

[0007] A throttle valve with a self-purification device for a dilution refrigerator includes a throttle valve high-pressure end structure, on which a throttle valve middle-end structure is installed, on which a throttle valve low-pressure end structure is installed. A compressor structure is installed with internal threads in the throttle valve high-pressure end structure. A copper mesh filter element is arranged in the throttle valve middle-end structure. A throttle micro-hole seat structure is jointly installed in the throttle valve middle-end structure and the throttle valve low-pressure end structure;

[0008] The middle structure of the throttle valve includes the middle part of the throttle valve seat. A circular filter element base is arranged inside the middle part of the throttle valve seat. The high-pressure end structure of the throttle valve includes the high-pressure end of the throttle valve seat installed on the middle part of the throttle valve seat. The low-pressure end structure of the throttle valve includes the low-pressure end of the throttle valve seat installed on the middle part of the throttle valve seat. Both ends of the middle part of the throttle valve seat are respectively provided with middle assembly ports for tightly installing with the high-pressure end and the low-pressure end of the throttle valve seat. The high-pressure end of the throttle valve seat and the low-pressure end of the throttle valve seat are respectively provided with high-pressure end assembly ports or low-pressure end assembly ports corresponding to the middle assembly ports;

[0009] The throttle micropore seat structure includes a throttle micropore base installed on the inner contours of the middle part of the throttle valve seat and the low-pressure end of the throttle valve seat. A flow-blocking baffle is arranged inside the throttle micropore base. A throttle micro-through hole is opened at the center position of the flow-blocking baffle.

[0010] Preferably, a high-pressure seal cover is installed at one end of the high-pressure end of the throttle valve seat away from the middle part of the throttle valve seat. Internal threads are provided on the inner contour of the high-pressure end of the throttle valve seat.

[0011] Preferably, a low-pressure seal cover is installed at one end of the middle part of the throttle valve seat away from the middle part of the throttle valve seat. A chamfer with a depth of half of the thickness of the low-pressure end of the throttle valve seat is opened on the surface of the low-pressure end of the throttle valve seat in contact with the low-pressure seal cover. Connection through holes are provided on both the connection through holes and the low-pressure seal cover.

[0012] Preferably, the inner diameter of the circular filter element base is half of the inner diameter of the middle part of the throttle valve seat. One end of the throttle micropore base is fitted with the circular filter element base. The other end of the throttle micropore base is fitted with the chamfer position of the low-pressure end of the throttle valve seat. The inner diameter of the throttle micropore base is larger than the through-hole diameter of the circular filter element base.

[0013] Preferably, a copper mesh filter element is assembled at one end of the circular filter element base away from the throttle micropore base. The high-pressure end of the throttle valve seat is internally threaded with a presser structure.

[0014] Preferably, the presser structure includes a presser threaded section threadedly connected to the high-pressure end of the throttle valve seat. A presser extrusion section is fixedly connected to the presser threaded section. A hexagonal groove and a flow through hole are jointly opened inside the presser threaded section and the presser extrusion section. The hexagonal groove and the flow through hole are connected and penetrate through the presser threaded section and the presser extrusion section.

[0015] Preferably, external threads matching the internal threads of the high-pressure end of the throttle valve seat are provided on the outer contour of the presser threaded section. The presser extrusion section presses against the copper mesh filter element.

[0016] The present invention also provides a manufacturing method for a throttle valve with a self-purifying device for a dilution refrigerator, comprising the following steps:

[0017] S1. The inner contour of the high-pressure end of the throttle valve seat is machined into an internal thread. The middle part of the throttle valve seat is made of a material with high thermal conductivity. The circular filter element base is arranged at a position 9 - 11 mm away from the contact surface between the high-pressure end and the middle part of the throttle valve seat. The inner diameter of the circular filter element base is half of the inner diameter of the middle part of the throttle valve seat. The high-pressure end assembly port and the low-pressure end assembly port are respectively machined at one end of the high-pressure end and the low-pressure end of the throttle valve seat close to the middle part of the throttle valve seat. The middle assembly ports are respectively machined at both ends of the middle part of the throttle valve seat. The length of the low-pressure end of the throttle valve seat is controlled such that the chamfer position of the low-pressure end of the throttle valve seat is exactly located at the end face of the throttle micropore base;

[0018] S2. The copper mesh filter element is formed by pressing multiple layers of copper mesh cut into a circular shape. The diameter of the copper mesh filter element is smaller than the diameter where the top of the internal thread of the high-pressure end of the throttle valve seat is located. The outer contour of the threaded section of the compressor is machined into an external thread matching the internal thread of the high-pressure end of the throttle valve seat. The width of the threaded section of the compressor is half of the extrusion section of the compressor. The diameter of the extrusion section of the compressor is smaller than the diameter where the bottom of the external thread of the threaded section of the compressor is located. The width of the hexagonal groove is four times the diameter of the flow through hole. The diameter of the flow through hole is the same as the inner diameter of the circular filter element base. The width of the threaded section of the compressor is half of the high-pressure end of the throttle valve seat;

[0019] S3. The cross-section of the throttle micropore seat structure is an I-shaped structure. One end of the throttle micropore base is closely attached to the circular filter element base, and the other end is located at the chamfer position of the low-pressure end of the throttle valve seat. The throttle micro through holes are formed by precision drilling technology. The diameter of the throttle micro through holes is controlled between 40 - 50 μm, and the cylindricity is ensured to be ±2 μm. Connecting through holes are respectively opened at the central positions of the high-pressure sealing cover and the low-pressure sealing cover for subsequent connection of high-pressure or low-pressure pipelines.

[0020] The beneficial effects of the present invention are as follows:

[0021] The throttle valve with a built-in purification device for a dilution refrigerator and its manufacturing method. Through integrated design, the structure of the throttle valve is compact. By placing the copper mesh filter element in the middle of the throttle valve seat and fixing it tightly through a compressor structure, the integrated design of the purification device and the throttle valve is achieved, effectively reducing the size of the device and facilitating its use in a dilution coolant with limited space. By using a copper mesh filter element supported by multiple layers of copper mesh, small particle impurities in the fluid can be effectively filtered, preventing the throttling micro-through holes from being blocked and ensuring the long-term stable operation of the dilution refrigerator. Between the high-pressure end of the throttle valve seat, the middle end of the throttle valve seat, and the low-pressure end of the throttle valve seat, they are connected by welding through the high-pressure end assembly port, the low-pressure end assembly port, and the middle-end assembly port, making the high-pressure end of the throttle valve seat, the middle end of the throttle valve seat, and the low-pressure end of the throttle valve seat form an integral body, ensuring the sealing reliability in an extremely low-temperature and high-pressure environment and effectively preventing leakage.

[0022] Other advantages, objectives, and features of the present invention will be described to some extent in the subsequent specification, and to some extent, will be obvious to those skilled in the art based on the study of the following text, or can be taught from the practice of the present invention. The objectives and other advantages of the present invention can be achieved and obtained through the following specification. Brief Description of the Drawings

[0023] Figure 1 It is a schematic diagram of the overall structure of the throttle valve with a built-in purification device for a dilution refrigerator according to the present invention;

[0024] Figure 2 It is a cross-sectional view of the internal structure according to the present invention;

[0025] Figure 3 It is a schematic diagram of the connection structure of the throttle valve seat according to the present invention;

[0026] Figure 4 It is a schematic diagram of the structure of the copper mesh filter element according to the present invention;

[0027] Figure 5 It is a schematic diagram of the throttling micro-hole seat structure according to the present invention;

[0028] Figure 6 It is a schematic diagram of the compressor structure according to the present invention.

[0029] In the figure: 1. Throttle valve high-pressure end structure; 11. High-pressure sealing cover; 12. Throttle valve seat high-pressure end; 13. Connection through-hole; 14. High-pressure end assembly port;

[0030] 2. Throttle valve middle-end structure; 21. Throttle valve seat middle-end; 22. Ring-shaped filter element base; 23. Middle-end assembly port;

[0031] 3. Throttle valve low-pressure end structure; 31. Throttle valve seat low-pressure end; 32. Low-pressure sealing cover; 33. Low-pressure end assembly port;

[0032] 4. Copper mesh filter element;

[0033] 5. Throttle micro-hole seat structure; 51. Throttle micro-hole base; 52. Flow-blocking baffle; 53. Throttle micro through-hole;

[0034] 6. Compressor structure; 61. Compressor threaded section; 62. Compressor extrusion section; 63. Hexagonal groove; 64. Flow through-hole. Detailed implementation manners

[0035] To make the objectives, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. Apparently, the described embodiments are some but not all of the embodiments of the present invention. Usually, the components of the embodiments of the present invention described and illustrated herein can be arranged and designed in various different configurations.

[0036] Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed present invention, but merely represents selected embodiments of the present invention. All other embodiments obtained by those of ordinary skill in the art based on the embodiments of the present invention without creative efforts shall fall within the protection scope of the present invention.

[0037] It should be noted that: Similar reference numerals and letters denote similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined and explained in subsequent drawings.

[0038] In the above description of the present invention, it should be noted that the orientation or positional relationship indicated by terms such as "one side", "the other side", etc. is based on the orientation or positional relationship shown in the drawings, or the orientation or positional relationship in which the product of the present invention is usually placed during use. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be construed as a limitation of the present invention. In addition, terms such as "first", "second", etc. are only used for distinguishing descriptions and cannot be construed as indicating or implying relative importance.

[0039] In addition, terms such as "the same" do not mean that the components must be absolutely the same, but there may be slight differences. The term "vertical" only means that the positional relationship between components is more vertical relative to "parallel", and does not mean that the structure must be completely vertical, but may be slightly inclined.

[0040] Please refer to Figure 1-6, the present invention provides a technical solution: a throttle valve with a self-purifying device for a dilution refrigerator. It includes a throttle valve high-pressure end structure 1, on which a throttle valve middle-end structure 2 is installed, and on the throttle valve middle-end structure 2, a throttle valve low-pressure end structure 3 is installed. A compressor structure 6 is installed in the throttle valve high-pressure end structure 1 by internal threading. A copper mesh filter element 4 is arranged inside the throttle valve middle-end structure 2, and a throttle micro-hole seat structure 5 is jointly installed inside the throttle valve middle-end structure 2 and the throttle valve low-pressure end structure 3.

[0041] The throttle valve middle-end structure 2 includes a throttle valve seat middle-end 21, inside which a circular filter element base 22 is arranged. The throttle valve high-pressure end structure 1 includes a throttle valve seat high-pressure end 12 installed on the throttle valve seat middle-end 21. The throttle valve low-pressure end structure 3 includes a throttle valve seat low-pressure end 31 installed on the throttle valve seat middle-end 21. At both ends of the throttle valve seat middle-end 21, there are middle-end assembly ports 23 for tightly installing with the throttle valve seat high-pressure end 12 and the throttle valve seat low-pressure end 31 respectively. On the throttle valve seat high-pressure end 12 and the throttle valve seat low-pressure end 31, there are respectively a high-pressure end assembly port 14 or a low-pressure end assembly port 33 corresponding to the middle-end assembly port 23.

[0042] The throttle micro-hole seat structure 5 includes a throttle micro-hole base 51 installed on the inner contours of the throttle valve seat middle-end 21 and the throttle valve seat low-pressure end 31. Inside the throttle micro-hole base 51, there is a flow-blocking baffle 52, and a throttle micro-hole 53 is opened at the center position of the flow-blocking baffle 52.

[0043] In the above way: the throttle valve seat high-pressure end 12, the throttle valve seat middle-end 21, and the throttle valve seat low-pressure end 31 are assembled into a whole through the cooperation between the high-pressure end assembly port 14, the middle-end assembly port 23, and the low-pressure end assembly port 33. The three are firmly combined into a complete valve body by welding technology, and there is a space inside the valve body to accommodate the copper mesh filter element 4, the throttle micro-hole seat structure 5, and the compressor structure 6. By installing the copper mesh filter element 4, the throttle micro-hole seat structure 5, and the compressor structure 6 on the valve body, a complete throttle valve is formed. And the purification function of the throttle valve is realized through the copper mesh filter element 4, the flow resistance is reduced through the throttle micro-hole seat structure 5, the sudden change of flow velocity is avoided, and the smoothness of the throttling process is ensured to achieve precise throttling.

[0044] Please refer to Figure 2 and 3 , at one end of the throttle valve seat high-pressure end 12 away from the throttle valve seat middle-end 21, a high-pressure sealing cover 11 is installed, and an internal thread is provided on the inner contour of the throttle valve seat high-pressure end 12.

[0045] A low-pressure sealing cover 32 is installed at one end of the throttle valve seat middle end 21 away from the throttle valve seat middle end 21, and a chamfer of half the thickness of the throttle valve seat low-pressure end 31 is provided on the side where the throttle valve seat low-pressure end 31 contacts the low-pressure sealing cover 32, and a connecting through hole 13 and the low-pressure sealing cover 32 are both provided with a connecting through hole 13.

[0046] The above method is adopted: the processing depth of the high-pressure end assembly port 14 and the low-pressure end assembly port 33 is 2mm of the middle-end structure of the throttle valve, the processing thickness is half of the thickness of the middle-end 21 of the throttle valve seat, and the angle is chamfered R0.5. The processing specifications of the middle-end assembly port 23 are consistent with the low-pressure end assembly port 33. The low-pressure end structure 3 of the throttle valve is made of a material with a high thermal rate to facilitate rapid thermal equilibrium at low temperatures. The right end face of the low-pressure end 31 of the throttle valve seat is chamfered, and the chamfering depth is half of the thickness of the low-pressure end 31 of the throttle valve seat.

[0047] See also Figure 2 , 4 and 5, the inner diameter of the annular filter element base 22 is half of the inner diameter of the middle end 21 of the throttle valve seat, one end of the throttling microporous base 51 is fitted with the annular filter element base 22, and the other end of the throttling microporous base 51 is fitted with the chamfered position of the low-pressure end 31 of the throttle valve seat, and the inner diameter of the throttling microporous base 51 is larger than the through hole diameter of the annular filter element base 22.

[0048] The above method is adopted: an I-shaped structure is formed by a throttling microporous base 51 and a baffle 52, and a throttling micro-through hole 53 is opened at the center of the baffle 52. The diameter of the throttling micro-through hole 53 is controlled to be 50μm. Since the I-shaped structure is designed to be longer on the left and shorter on the right, it is helpful to improve the fluid dynamic characteristics, reduce the flow resistance or stabilize the flow state. The cylindricity of the throttling micro-through hole 53 is required to be controlled within ±2μm to avoid sudden changes in the flow velocity of the fluid when passing through the micropores, ensuring the smoothness of the throttling process. After the high-pressure airflow is purified by the copper mesh filter element 4, it can only flow through the throttling micro-through hole 53 to achieve precise throttling.

[0049] See also Figure 2 and 6 The end of the annular filter element base 22 away from the throttling microporous base 51 is equipped with a copper mesh filter element 4, and the high-pressure end 12 of the throttling valve seat is internally threadedly connected with a tightening device structure 6.

[0050] The clamp structure 6 includes a clamp threaded section 61 threadedly connected to the high-pressure end 12 of the throttle valve seat, and a clamp extrusion section 62 is fixedly connected to the clamp threaded section 61. The clamp threaded section 61 and the clamp extrusion section 62 are jointly provided with a hexagonal groove 63 and a flow through hole 64. The hexagonal groove 63 and the flow through hole 64 are connected to each other and penetrate the clamp threaded section 61 and the clamp extrusion section 62.

[0051] An external thread matching the internal thread of the high-pressure end 12 of the throttle valve seat is provided on the outer contour of the threaded section 61 of the presser, and the pressing section 62 of the presser is pressed against the copper mesh filter element 4.

[0052] In the above manner: after the copper mesh filter element 4 is cut into a circular shape from multiple layers of 200-mesh copper mesh and then formed by pressing, since the diameter of the structure 6 of the presser is slightly smaller than the top diameter of the internal thread of the high-pressure end 12 of the throttle valve seat, it is ensured that it can smoothly pass through the threaded section and be pressed by the pressing section 62 of the presser against the annular filter element base 22.

[0053] Since the hexagonal groove 63 is designed in an internal hexagonal shape, which is convenient for using an internal hexagonal wrench for tightening operations, after the pressing section 62 of the presser is rotated and installed in the high-pressure end 12 of the throttle valve seat along with the threaded section 61 of the presser, it always presses the copper mesh filter element 4 to ensure its close fit with the annular filter element base 22. Since the diameter of the flow through hole 64 is the same as that of the annular filter element base 22, it is ensured that the fluid can flow smoothly.

[0054] During the entire manufacturing process, attention should be paid to cleanliness to avoid introducing new impurities. After all welding processes are completed, leak detection is carried out to ensure the sealing performance of the throttle valve.

[0055] The present invention also provides a manufacturing method for a throttle valve of a self-purifying device for a dilution refrigerator, comprising the following steps:

[0056] S1. The internal contour of the high-pressure end 12 of the throttle valve seat is machined into an internal thread. The middle end 21 of the throttle valve seat is made of a material with high thermal conductivity. The annular filter element base 22 is arranged at a position 9 - 11 mm away from the contact surface between the high-pressure end 12 of the throttle valve seat and the middle end 21 of the throttle valve seat. The inner diameter of the annular filter element base 22 is half of the inner diameter of the middle end 21 of the throttle valve seat. The high-pressure end assembly port 14 and the low-pressure end assembly port 33 are respectively machined at one end of the high-pressure end 12 and the low-pressure end 31 of the throttle valve seat close to the middle end 21 of the throttle valve seat. The middle end assembly ports 23 are respectively machined at both ends of the middle end 21 of the throttle valve seat. The length of the low-pressure end 31 of the throttle valve seat is controlled such that the chamfer position of the low-pressure end 31 of the throttle valve seat is exactly located at the end face of the throttle micro-hole base 51.

[0057] S2. The copper mesh filter element 4 is formed by pressing multiple layers of circularly cut copper meshes. The diameter of the copper mesh filter element 4 is smaller than the diameter where the inner thread top of the high-pressure end 12 of the throttle valve seat is located. The outer contour of the threaded section 61 of the compressor is machined into an external thread that matches the inner thread of the high-pressure end 12 of the throttle valve seat. The width of the threaded section 61 of the compressor is half of the width of the extrusion section 62 of the compressor. The diameter of the extrusion section 62 of the compressor is smaller than the diameter where the bottom of the external thread of the threaded section 61 of the compressor is located. The width of the hexagonal groove 63 is four times the diameter of the flow through hole 64. The diameter of the flow through hole 64 is the same as the inner diameter of the annular filter element base 22. The width of the threaded section 61 of the compressor is half of the high-pressure end 12 of the throttle valve seat.

[0058] S3. The cross-section of the throttle micropore seat structure 5 is an I-shaped structure. One end of the throttle micropore base 51 is closely attached to the annular filter element base 22, and the other end is located at the chamfer position of the low-pressure end 31 of the throttle valve seat. The throttle micro through hole 53 adopts precision drilling technology to control the diameter of the throttle micro through hole 53 between 40 and 60 μm and ensure its cylindricity is ±2 μm. Connecting through holes 13 are respectively opened at the central positions of the high-pressure seal cover 11 and the low-pressure seal cover 32 for subsequent connection to high-pressure or low-pressure pipelines.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention and are not intended to limit them. Although the present invention has been described in detail with reference to the preferred embodiments, those of ordinary skill in the art should understand that the technical solutions of the present invention can be modified or equivalently replaced without departing from the purpose and scope of the technical solutions of the present invention, and they should all be covered within the scope of the claims of the present invention.

Claims

1. A throttle valve with a built-in purification device for a dilution refrigerator, comprising a throttle valve high-pressure end structure (1), a throttle valve middle-end structure (2) is installed on the throttle valve high-pressure end structure (1), a throttle valve low-pressure end structure (3) is installed on the throttle valve middle-end structure (2), a compressor structure (6) is installed in the internal thread of the throttle valve high-pressure end structure (1), a copper mesh filter element (4) is arranged in the throttle valve middle-end structure (2), and a throttle micro-hole seat structure (5) is jointly installed in the throttle valve middle-end structure (2) and the throttle valve low-pressure end structure (3), characterized in that: The throttle valve middle-end structure (2) includes a throttle valve seat middle-end (21), a circular filter element base (22) is arranged in the throttle valve seat middle-end (21), the throttle valve high-pressure end structure (1) includes a throttle valve seat high-pressure end (12) installed on the throttle valve seat middle-end (21), the throttle valve low-pressure end structure (3) includes a throttle valve seat low-pressure end (31) installed on the throttle valve seat middle-end (21), both ends of the throttle valve seat middle-end (21) are respectively provided with a middle-end assembly port (23) for tightly installing with the throttle valve seat high-pressure end (12) and the throttle valve seat low-pressure end (31), and the throttle valve seat high-pressure end (12) and the throttle valve seat low-pressure end (31) are respectively provided with a high-pressure end assembly port (14) or a low-pressure end assembly port (33) corresponding to the middle-end assembly port (23); The throttle micro-hole seat structure (5) includes a throttle micro-hole base (51) installed on the inner contours of the throttle valve seat middle-end (21) and the throttle valve seat low-pressure end (31), a flow-blocking baffle (52) is arranged in the throttle micro-hole base (51), and a throttle micro-through hole (53) is opened at the center position of the flow-blocking baffle (52).

2. The throttle valve with a self-purification device for a dilution refrigerator according to claim 1, characterized in that: A high-pressure sealing cover (11) is installed at one end of the throttle valve seat high-pressure end (12) far from the throttle valve seat middle-end (21), and an internal thread is provided on the inner contour of the throttle valve seat high-pressure end (12).

3. The throttle valve with a self-purification device for a dilution refrigerator according to claim 2, characterized in that: A low-pressure sealing cover (32) is installed at one end of the throttle valve seat middle-end (21) far from the throttle valve seat middle-end (21), a chamfer with half the thickness of the throttle valve seat low-pressure end (31) is opened on the surface of the throttle valve seat low-pressure end (31) in contact with the low-pressure sealing cover (32), and a connection through hole (13) is opened on both the connection through hole (13) and the low-pressure sealing cover (32).

4. The throttle valve with a self-purification device for a dilution refrigerator according to claim 3, characterized in that: The inner diameter of the circular filter element base (22) is half of the inner diameter of the throttle valve seat middle-end (21), one end of the throttle micro-hole base (51) is attached to the circular filter element base (22), the other end of the throttle micro-hole base (51) is attached to the chamfer position of the throttle valve seat low-pressure end (31), and the inner diameter of the throttle micro-hole base (51) is larger than the through-hole diameter of the circular filter element base (22).

5. The throttle valve with a self-purification device for a dilution refrigerator according to claim 4, characterized in that: A copper mesh filter element (4) is assembled at one end of the circular filter element base (22) far from the throttle micro-hole base (51), and a compressor structure (6) is connected to the internal thread of the throttle valve seat high-pressure end (12).

6. The throttle valve with a self-purification device for a dilution refrigerator according to claim 5, characterized in that: The pressing device structure (6) includes a pressing device threaded section (61) threadedly connected to the high-pressure end (12) of the throttle valve seat. A pressing device extrusion section (62) is fixedly connected to the pressing device threaded section (61). A hexagonal groove (63) and a flow through hole (64) are jointly formed in the pressing device threaded section (61) and the pressing device extrusion section (62). The hexagonal groove (63) and the flow through hole (64) are communicated with each other and penetrate through the pressing device threaded section (61) and the pressing device extrusion section (62).

7. The throttle valve with a self-purification device for a dilution refrigerator according to claim 6, characterized in that: An external thread matching the internal thread of the high-pressure end (12) of the throttle valve seat is provided on the outer contour of the pressing device threaded section (61). The pressing device extrusion section (62) is pressed against the copper mesh filter element (4).

8. A manufacturing method of a throttle valve with a self-purification device for a dilution refrigerator, applied to a throttle valve with a self-purification device for a dilution refrigerator as described in any one of claims 1-7, characterized in that: It includes the following steps: S1. The inner contour of the high-pressure end (12) of the throttle valve seat is machined into an internal thread. The middle end (21) of the throttle valve seat is made of a material with high thermal conductivity. The annular filter element base (22) is arranged at a position 9 - 11 mm away from the contact surface between the high-pressure end (12) of the throttle valve seat and the middle end (21) of the throttle valve seat. The inner diameter of the annular filter element base (22) is half of the inner diameter of the middle end (21) of the throttle valve seat. The high-pressure end assembly port (14) and the low-pressure end assembly port (33) are respectively machined at one end of the high-pressure end (12) of the throttle valve seat and the low-pressure end (31) of the throttle valve seat close to the middle end (21) of the throttle valve seat. The middle end assembly ports (23) are respectively machined at both ends of the middle end (21) of the throttle valve seat. The length of the low-pressure end (31) of the throttle valve seat is controlled such that the chamfer position of the low-pressure end (31) of the throttle valve seat is exactly located at the end face of the throttle micro-hole base (51). S2. The copper mesh filter element (4) is formed by pressing multiple layers of copper mesh cut into a circular shape. The diameter of the copper mesh filter element (4) is smaller than the diameter where the top of the internal thread of the high-pressure end (12) of the throttle valve seat is located. The outer contour of the pressing device threaded section (61) is machined into an external thread matching the internal thread of the high-pressure end (12) of the throttle valve seat. The width of the pressing device threaded section (61) is half of that of the pressing device extrusion section (62). The diameter of the pressing device extrusion section (62) is smaller than the diameter where the bottom of the external thread of the pressing device threaded section (61) is located. The width of the hexagonal groove (63) is four times that of the flow through hole (64). The diameter of the flow through hole (64) is the same as the inner diameter of the annular filter element base (22). The width of the pressing device threaded section (61) is half of that of the high-pressure end (12) of the throttle valve seat. S3. The cross-section of the throttle micro-hole seat structure (5) is an I-shaped structure. One end of the throttle micro-hole base (51) is closely attached to the annular filter element base (22), and the other end is located at the chamfer position of the low-pressure end (31) of the throttle valve seat. The throttle micro-hole (53) adopts precision drilling technology. The diameter of the throttle micro-hole (53) is controlled between 40 - 60 μm, and its cylindricity is ensured to be ±2 μm. Connecting through holes (13) are respectively opened at the central positions of the high-pressure sealing cover (11) and the low-pressure sealing cover (32) for subsequent connection of high-pressure or low-pressure pipelines.

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