Quick replacement structure of low-temperature refrigerator

Abstract

The invention relates to the technical field of low temperature, and provides a quick replacement structure of a low-temperature refrigerator, which is used for realizing heat conduction of a device and the low-temperature refrigerator, and the device is arranged in a Dewar and comprises a first heat conduction piece connected with a cold head of the low-temperature refrigerator; the second heat conduction piece is detachably connected with the first heat conduction piece; the second heat conduction piece is used for being connected with a device; the top end of the cylinder body is connected with the second heat conduction piece in an embedded manner; the first heat conduction piece is located on the inner side of the barrel; the low-temperature refrigerator cold head penetrates through the bottom end of the cylinder; a low-temperature refrigerator cavity is formed in the inner side of the barrel, and a Dewar cavity is formed in the outer side of the barrel. The corrugated pipe is arranged on the periphery of the cylinder in a sealed mode. According to the quick replacement structure of the low-temperature refrigerator, efficient heat transfer can be achieved through the arrangement of the first heat conduction piece and the second heat conduction piece, appropriate mechanical coupling of the low-temperature refrigerator and a Dewar where a device is located can be achieved through telescopic movement of the middle section of the corrugated pipe, meanwhile, the heat conduction path is prolonged, and solid conduction heat leakage is reduced.

Description

Technical Field

[0001] The invention relates to the field of cryogenic technology, and in particular to a rapid replacement structure for a cryogenic refrigerator. Background Art

[0002] The microwave surface resistance of high-temperature superconducting films is nearly three orders of magnitude smaller than that of conventional metals. The microwave devices made from them have the advantages of low insertion loss, high frequency selectivity, and steep passband edges. If they are applied to the receiving front end, the receiver will have an extremely low noise factor, while the sensitivity and selectivity will be greatly improved. At present, the receiving front-end subsystem composed of high-temperature superconducting filters, low-temperature low-noise amplifiers, and refrigerators has been used in the fields of civil communications (mobile communication base stations, radio astronomy, etc.) and military communications (radar, measurement and control, etc.), with good economic and social benefits.

[0003] Given the high reliance of the high-temperature superconducting microwave receiving front end on the low-temperature environment, the life and reliability of its cooling source are particularly important. The commonly used cooling sources are gas bearing Stirling refrigerators or Stirling pulse tube refrigerators, both of which have large cooling capacity, small size and light weight. In order to reduce heat leakage loss, the refrigerator is often welded and integrated with the dewar. The defect of this structure is that once the refrigerator fails, the entire system will be scrapped because the cooling source cannot be replaced for repair. At the same time, the vacuum of the dewar must be destroyed to remove the internal components, which greatly affects the working efficiency of the receiving front end.

[0004] In order to achieve the connection between the refrigerator and the Dewar, a direct coupling structure or an indirect coupling structure is usually adopted in the prior art. The direct coupling structure can directly contact the cold head of the refrigerator with the Dewar cooling structure, and with the assistance of thermal interface materials, efficient heat transfer can be achieved. However, precise structural design and processing are required to ensure the appropriate coupling compression amount. If it is too large, the cold head of the refrigerator will be deformed and damaged under long-term extrusion. If it is too small, the interface contact thermal resistance will increase, affecting the cooling effect. The indirect coupling structure realizes mechanical coupling by setting a flexible transition piece between the cold head of the refrigerator and the Dewar cooling structure. Although the fault tolerance margin of the structure is increased, the increase in heat transfer links will affect the cooling effect and increase the complexity of the system.

[0005] Therefore, how to provide a low-temperature refrigerator quick replacement structure that takes into account both efficient heat transfer and flexible coupling is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0006] The present invention provides a low-temperature refrigerator quick replacement structure, which is used to solve the defect that efficient heat transfer and flexible coupling cannot be taken into account in the prior art, and realize the quick replacement of the refrigerator.

[0007] The present invention provides a low-temperature refrigerator quick replacement structure, which is used to achieve heat conduction between a device and a low-temperature refrigerator, wherein the device is placed inside a dewar, and the quick replacement structure comprises: A first heat conducting member connected to a cold head of the cryogenic refrigerator; A second heat-conducting member, detachably connected to the first heat-conducting member; and the second heat-conducting member is used to be connected to the device; The cylinder is opened at the top and bottom, and the second heat-conducting member is embedded in the top; the first heat-conducting member is located on the inner side of the cylinder; the cold head of the cryogenic refrigerator passes through the bottom end of the cylinder; the inner side of the cylinder forms a cryogenic refrigerator cavity, and the outer side of the cylinder is a Dewar cavity; The bellows is sealed and arranged on the outer periphery of the cylinder.

[0008] According to a low-temperature refrigerator quick replacement structure provided by the present invention, it also includes a first transition piece, and the cylinder includes: An inner cylinder, the first heat-conducting member and the second heat-conducting member are arranged inside the inner cylinder, and the inner cylinder is connected to the second heat-conducting member; and an outer ring is integrally extended outward from the bottom end of the inner cylinder; The inner side of the bottom end of the outer cylinder is sealed and connected to the outer ring, the top end of the outer cylinder is connected to the first transition piece, and the bottom end of the outer cylinder is suspended.

[0009] A low-temperature refrigerator quick replacement structure provided by the present invention also includes: The second transition piece and the connection blind plate are both located at the bottom end of the outer side of the outer cylinder, and the second transition piece is used for sealing connection between the bellows and the connection blind plate.

[0010] According to a rapid replacement structure of a low-temperature refrigerator provided by the present invention, the first transition piece and the second transition piece are sealed with the bellows by silver welding.

[0011] A low-temperature refrigerator quick-replacement structure provided according to the present invention further comprises a KF joint, the bottom side of the connecting blind plate is connected to the KF joint, and the KF joint is connected to the low-temperature refrigerator.

[0012] According to a low-temperature refrigerator quick-change structure provided by the present invention, an exhaust pipe is connected to the KF joint.

[0013] According to a low-temperature refrigerator quick replacement structure provided by the present invention, the annular gap between the cold head of the low-temperature refrigerator and the inner cylinder is filled with insulating material.

[0014] A low-temperature refrigerator quick replacement structure provided according to the present invention also includes a restraining member, and the restraining member is provided in multiple groups. The multiple groups of restraining members are distributed on the outer periphery of the bellows, and the two ends of each group of restraining members are respectively connected to the first transition member and the connecting blind plate.

[0015] According to a low-temperature refrigerator quick replacement structure provided by the present invention, each group of restraints comprises: A pair of fixing nuts, respectively fixedly disposed on the first transition piece and the connecting blind plate; A screw rod is inserted into the inner side of the pair of fixing nuts; A pair of movable nuts are respectively adapted to be connected with the top end and the bottom end of the screw rod.

[0016] According to a low-temperature refrigerator quick-change structure provided by the present invention, the fixed nut is larger in size than the screw rod and the movable nut.

[0017] The low-temperature refrigerator quick replacement structure provided by the present invention is detachably connected to the first heat-conducting part through the second heat-conducting part, and the second heat-conducting part is used to connect with the device in the dewar. The cylinder is open at the top and bottom, and the second heat-conducting part is embedded in the top and the cylinder is connected to the second heat-conducting part; the first heat-conducting part is located on the inner side of the cylinder; the cold head of the low-temperature refrigerator passes through the bottom end of the cylinder and is connected to the first heat-conducting part; efficient heat transfer is achieved through the first heat-conducting part and the second heat-conducting part. The inner side of the cylinder forms the low-temperature refrigerator cavity, and the outer side of the cylinder is the dewar cavity; the bellows seal is arranged on the outer periphery of the cylinder, and the middle section of the bellows is retractable and movable, which can realize the appropriate mechanical coupling between the low-temperature refrigerator and the dewar where the device is located, and at the same time extend the heat conduction path and reduce the solid conduction heat leakage.

[0018] The two ends of the restraining member are respectively connected to the first transition member and the connecting blind plate to prevent deformation due to excessive pressure difference between the inside and outside of the two cavities during replacement.

[0019] The long path arrangement of the inner tube and the outer tube can reduce the heat leakage of solid heat conduction at the cold head.

[0020] The vacuum degree of the cavity where the cryogenic refrigerator is located can be adjusted individually to minimize heat leakage from residual gas in the annular gap.

[0021] The combination of the fixed nut, the lead screw and the movable nut can adjust the telescopic degree of the flexible bellows and constrain the support, while ensuring that the structure will not be deformed due to excessive internal and external pressure difference during replacement. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0023] Figure 1 It is a schematic diagram of the installation of the quick replacement structure of the low-temperature refrigerator provided by the present invention.

[0024] Figure 2 It is a cross-sectional view of the low-temperature refrigerator quick replacement structure provided by the present invention.

[0025] Figure 3 It is a schematic diagram of the appearance of the low-temperature refrigerator quick replacement structure provided by the present invention.

[0026] Reference numerals: 1. First heat-conducting member; 2. Second heat-conducting member; 3. Cylinder body; 4. Bellows; 5. Constraint; 6. First transition member; 7. Second transition member; 8. Connecting blind plate; 9. KF joint; 10. Exhaust pipe; 31. Inner cylinder; 32. Outer ring; 33. Outer cylinder; 51. Fixing nut; 52. Screw rod; 53. Movable nut; 100. Cryogenic refrigerator; 200. Dewar; 61. First vertical portion; 62. Horizontal portion; 63. Second vertical portion. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] In the description of the embodiments of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the embodiments of the present invention and simplifying the description, and do not indicate or imply that the devices or elements referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as limitations on the embodiments of the present invention. In addition, the terms "first", "second", and "third" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0029] Combine the following Figure 1-Figure 3The invention describes a quick replacement structure of a low-temperature refrigerator.

[0030] like Figure 1 As shown, an embodiment of the present invention provides a low-temperature refrigerator quick replacement structure to solve the problem in the prior art that a high-temperature superconducting microwave receiving front-end cold source failure cannot be repaired or replaced, while taking into account efficient heat transfer and flexible coupling, and realizing the replacement of the low-temperature refrigerator without destroying the Dewar vacuum.

[0031] The low-temperature refrigerator quick replacement structure provided in the embodiment of the present invention realizes efficient heat transfer and flexible coupling between the dewar where the device is located and the low-temperature refrigerator, and at the same time spatially isolates the dewar where the device is located and the low-temperature refrigerator into two cavities, so that the vacuum does not interfere with each other.

[0032] like Figure 2 and Figure 3 As shown, an embodiment of the present invention provides a low-temperature refrigerator quick replacement structure, including a first heat-conducting member 1, a second heat-conducting member 2, a cylinder 3, a bellows 4 and a restraining member 5.

[0033] Among them, the first heat-conducting member 1 is installed on the cold head of the cryogenic refrigerator, and the second heat-conducting member 2 is detachably connected to the first heat-conducting member 1, and is usually tightly matched through a threaded connection to achieve efficient heat transfer. The second heat-conducting member 2 is used to connect with the device in the Dewar. The specific installation method can be to leave a threaded hole on the second heat-conducting member 2, and the threaded hole is connected to the device. When the area of ​​the device is larger than the area of ​​the second heat-conducting member 2 or there is a special installation position requirement, a cooling structure can also be set between the device and the second heat-conducting member 2 to improve the cooling efficiency.

[0034] The cylinder 3 is open at the top and bottom, and the second heat-conducting member 2 is embedded at the top, and the cylinder 3 is connected to the second heat-conducting member 2; the first heat-conducting member 1 is located inside the cylinder 3; the cold head of the cryogenic refrigerator passes through the bottom of the cylinder 3 and is connected to the first heat-conducting member 1; the inside of the cylinder 3 forms a cryogenic refrigerator cavity, and the outside of the cylinder 3 is a Dewar cavity. The arrangement of the cylinder 3 realizes the isolation and sealing of the Dewar cavity where the device is located and the cryogenic refrigerator cavity, while extending the heat conduction path and reducing the solid conduction heat leakage of the first heat-conducting member 1 and the second heat-conducting member 2.

[0035] Both ends of the bellows 4 are sealed on the outer periphery of the cylinder 3, and the middle section of the bellows 4 is retractable to ensure the coupling margin, while extending the heat conduction path and reducing solid conduction heat leakage.

[0036] The low-temperature refrigerator quick replacement structure provided in the embodiment of the present invention can complete the replacement of the low-temperature refrigerator within a few minutes without destroying the vacuum of the dewar where the device is located; the threaded cooperation of the first heat conducting member 1 and the second heat conducting member 2 can achieve close contact and efficient heat transfer between the low-temperature refrigerator 100 and the device; the telescopic characteristics of the bellows 4 can achieve appropriate mechanical coupling between the low-temperature refrigerator 100 and the dewar where the device is located.

[0037] It should be noted that the first heat conducting member 1 and the second heat conducting member 2 are usually made of copper, which has a good heat conducting effect.

[0038] When a flexible bellows is used, in order to better achieve a sealed connection between the bellows 4 and the cylinder 3, in a feasible embodiment of the present invention, a first transition piece 6 is further included. The cylinder 3 includes an inner cylinder 31 and an outer cylinder 33. The inner side of the inner cylinder 31 is provided with a first heat-conducting member 1 and a second heat-conducting member 2, and the inner cylinder 31 is connected to the second heat-conducting member 2, while the inner cylinder 31 is not connected to the first heat-conducting member 1. An outer ring 32 is integrally extended outward from the bottom end of the inner cylinder 31. The inner side of the bottom end of the outer cylinder 33 is sealed and connected to the outer ring 32. The top end of the outer cylinder 33 is sealed and connected to the first transition piece 6, and the bottom end of the outer cylinder 33 is suspended. The long path setting of the gap between the inner cylinder 31 and the outer cylinder 33 can also reduce the heat leakage of solid heat conduction at the cold head.

[0039] Furthermore, the inner cylinder 31 and the second heat conducting member 2 are silver-welded, the outer cylinder 33 and the outer ring 32 are argon arc welded, and the outer cylinder 33 and the first transition member 6 are also argon arc welded.

[0040] The bellows 4 may be a flexible bellows or a customized disc bellows. When a customized disc bellows is used, the disc bellows may be directly connected to the outer cylinder 33 and the connecting blind plate 8 by welding.

[0041] In a feasible embodiment of the present invention, it also includes a second transition piece 7 and a connecting blind plate 8, both of which are located at the bottom end of the outer side of the outer cylinder 33, the second transition piece 7 is located on the top side of the connecting blind plate 8, and the second transition piece 7 is used for the sealing connection between the bellows 4 and the connecting blind plate 8.

[0042] More specifically, the first transition piece 6 and the second transition piece 7 are sealed with the bellows 4 by silver welding, and the middle section of the bellows 4 is retractable and movable to ensure the coupling margin, while extending the heat conduction path and reducing solid conduction heat leakage.

[0043] Furthermore, the first transition piece 6 is annular, and includes a first vertical portion 61, a horizontal portion 62, and a second vertical portion 63. The inner periphery of the first vertical portion 61 is welded to the outer side of the outer cylinder 33; the horizontal portion 62 is vertically connected to the first vertical portion 61; the second vertical portion 63 is vertically connected to one end of the horizontal portion 62 facing away from the first vertical portion 61, and the second vertical portion 63 and the first vertical portion 61 are distributed on both sides of the horizontal portion 62. The horizontal portion 62 and the second vertical portion 63 are both welded and fixed to the bellows 4. Through the above structural arrangement, the isolation and sealing of the Dewar cavity where the device is located and the cavity of the cryogenic refrigerator can be better achieved.

[0044] In addition, the shape of the second transition piece 7 is the same as that of the first transition piece 6 , except that the first vertical portion of the second transition piece 7 is not connected to the outer cylinder 33 , and the outer side thereof is welded to the inner periphery of the connecting blind plate 8 .

[0045] In a feasible embodiment of the present invention, a KF joint 9 is further included. The bottom side of the connecting blind plate 8 is welded to the KF joint 9, and the KF joint 9 is sealedly connected to the low-temperature refrigerator through a clamp.

[0046] In a feasible embodiment of the present invention, the KF connector 9 is connected with an exhaust pipe 10, which is welded to the reserved hole of the KF connector 9, and the vacuum degree of the low-temperature refrigerator cavity can be adjusted by an external exhaust pump.

[0047] The first transition piece 6, the second transition piece 7 and the exhaust pipe 10 are preferably made of stainless steel.

[0048] In another feasible embodiment of the present invention, in situations where the cooling time or residual gas heat leakage control requirements are not high, there is no need to set up an exhaust pipe, and the annular gap between the cold head of the low-temperature refrigerator and the inner cylinder 31 can be filled with insulating material, thereby improving the operating convenience.

[0049] Through the above two embodiments, the heat leakage of residual gas in the annular gap can be reduced as much as possible.

[0050] In a feasible embodiment of the present invention, it also includes a restraint member 5, the two ends of which are respectively connected to the first transition member 6 and the connecting blind plate 8. The restraint member 5 can ensure appropriate heat transfer and mechanical coupling effects to prevent deformation due to excessive pressure difference between the inside and outside of the two cavities during replacement.

[0051] There are multiple groups of restraint members 5 , and the multiple groups of restraint members 5 are distributed on the outer circumference of the bellows 4 . By providing the multiple groups of restraint members 5 , uniform restraint of the bellows 4 can be achieved.

[0052] In a feasible embodiment of the present invention, each set of constraint members 5 includes a pair of fixed nuts 51, a screw rod 52 and a pair of movable nuts 53. The pair of fixed nuts 51 are respectively fixedly arranged on the first transition member 6 and the connection blind plate 8; the screw rod 52 is inserted into the inner side of the pair of fixed nuts 51; and the pair of movable nuts 53 are respectively adapted to be connected with the top and bottom ends of the screw rod 52. The movable nut 53 at the upper end realizes the distance adjustment function, and the movable nut 53 at the lower end is stacked with the corresponding fixed nut 51 to ensure that the screw rod 52 has a certain insertion depth constraint.

[0053] To facilitate operation, in a feasible embodiment of the present invention, the model of the fixed nut 51 is slightly larger than the screw rod 52 and the movable nut 53 (for example, the screw rod 52 and the movable nut 53 are M3, and the fixed nut 51 is M4). By adjusting the movable nut 53, the compression amount of the flexible bellows can be controlled to ensure appropriate heat transfer and mechanical coupling effects; and by constraining the fixed nut 51, deformation due to excessive pressure difference between the inside and outside of the two cavities during replacement can be prevented.

[0054] The method for using the low-temperature refrigerator quick replacement structure provided by the present invention is as follows: (1) Use a molecular pump unit to pump the vacuum of the dewar 200 where the device is located and the low-temperature refrigerator 100 cavity to 10 -3 Pa, the exhaust pipeline is immediately cut off and sealed; (2) Start the cryogenic refrigerator 100 to reduce the temperature of the device side to below the superconducting transition temperature and keep it stable, and the device enters the working state; (3) If the cryogenic refrigerator 100 fails and stops, cut off all communications, loosen the KF clamp between the cryogenic refrigerator and the quick-change structure, and unscrew the dewar where the device is located from the faulty refrigerator by rotating it; (4) Prepare a new refrigerator, and tighten the Dewar where the device is located to the low-temperature refrigerator by screwing the first heat-conducting member and the second heat-conducting member together; (5) Connect the communication and refrigerator exhaust pipelines to evacuate the air, and start the new refrigerator at the same time; (6) Cut off the exhaust pipe and seal it, wait until the device side recovers to below the superconducting transition temperature, and then re-enter the working state.

[0055] The low-temperature refrigerator quick replacement structure provided by the present invention can be used in any occasion where a refrigerator needs to be quickly replaced, and is not limited to the application of a high-temperature superconducting microwave receiving front end.

[0056] The low temperature refrigerator may be a Stirling pulse tube refrigerator or a gas bearing Stirling refrigerator.

[0057] In the description of the embodiments of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "connected" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium. For ordinary technicians in this field, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific circumstances.

[0058] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "mode", "specific mode", or "some modes" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or mode are included in at least one embodiment or mode of the embodiment of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or mode. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or modes in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or modes described in this specification and the features of the different embodiments or modes, without contradiction.

[0059] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that they can still modify the technical solutions described in the aforementioned embodiments, or make equivalent replacements for some of the technical features therein. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A low temperature refrigerator quick replacement structure, used for achieving heat conduction between a device and a low temperature refrigerator (100), wherein the device is placed inside a dewar (200), characterized in that: The quick replacement structure comprises: A first heat conducting member (1) connected to a cold head of the low-temperature refrigerator (100); A second heat conducting member (2) is detachably connected to the first heat conducting member (1); and the second heat conducting member (2) is used to be connected to the device; The cylinder (3) is open at the top and bottom, and the second heat-conducting member (2) is embedded at the top; the first heat-conducting member (1) is located on the inner side of the cylinder (3); the cold head of the low-temperature refrigerator passes through the bottom end of the cylinder (3); the inner side of the cylinder (3) forms a low-temperature refrigerator cavity, and the outer side of the cylinder (3) is a Dewar cavity; The bellows (4) is sealingly arranged on the outer periphery of the cylinder (3).

2. The low-temperature refrigerator quick replacement structure according to claim 1, characterized in that: It also includes a first transition piece (6), and the cylinder (3) includes: An inner cylinder (31), the first heat-conducting member (1) and the second heat-conducting member (2) being arranged on the inner side thereof, and the inner cylinder (31) being connected to the second heat-conducting member (2); and an outer ring (32) extending outwardly from the bottom end of the inner cylinder (31); The inner side of the bottom end of the outer cylinder (33) is sealedly connected to the outer ring (32), the top end of the outer cylinder (33) is connected to the first transition piece (6), and the bottom end of the outer cylinder (33) is suspended in the air.

3. The low temperature refrigerator quick replacement structure according to claim 2, characterized in that: Also includes: The second transition piece (7) and the connecting blind plate (8) are both located at the bottom end of the outer side of the outer cylinder (33), and the second transition piece (7) is used for sealing connection between the bellows (4) and the connecting blind plate (8).

4. The low-temperature refrigerator quick replacement structure according to claim 3, characterized in that: The first transition piece (6) and the second transition piece (7) are sealed with the bellows (4) by silver welding.

5. The low temperature refrigerator quick replacement structure according to claim 3, characterized in that: It also comprises a KF joint (9), the bottom side of the connecting blind plate (8) is connected to the KF joint (9), and the KF joint (9) is connected to the low-temperature refrigerator.

6. The low-temperature refrigerator quick replacement structure according to claim 5, characterized in that: The KF joint (9) is connected to an exhaust pipe (10).

7. The low-temperature refrigerator quick replacement structure according to claim 5, characterized in that: The annular gap between the cold head of the low-temperature refrigerator (100) and the inner cylinder (31) is filled with a heat insulating material.

8. The low-temperature refrigerator quick replacement structure according to claim 5, characterized in that: It also includes a restraining member (5), wherein the restraining member (5) is provided in a plurality of groups, the plurality of groups of restraining members (5) are distributed on the outer circumference of the bellows (4), and the two ends of each group of restraining members (5) are respectively connected to the first transition member (6) and the connecting blind plate (8).

9. The low temperature refrigerator quick replacement structure according to claim 8, characterized in that: Each set of the restraining members (5) comprises: a pair of fixing nuts (51) respectively fixedly disposed on the first transition piece (6) and the connecting blind plate (8); A screw rod (52) is inserted into the inner side of the pair of fixing nuts (51); A pair of movable nuts (53) are respectively adapted to be connected to the top end and the bottom end of the screw rod (52).

10. The low temperature refrigerator quick replacement structure according to claim 9, characterized in that: The fixed nut (51) is larger in size than the screw rod (52) and the movable nut (53).

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