Dry-type ultralow-vibration closed-cycle low-temperature liquefaction system

Abstract

The utility model belongs to the technical field of ultralow-vibration low-temperature refrigeration, and particularly relates to a dry-type ultralow-vibration closed-cycle low-temperature liquefaction system which comprises a liquefier part, the liquefier part is connected with a low-temperature thermostat part through a low-loss liquid conveying pipe part, and the low-temperature thermostat part is connected with the liquefier part through a circulation gas circuit part. According to the dry-type ultralow-vibration closed-cycle low-temperature liquefaction system, a first-stage cold head and a second-stage cold head in a refrigerating machine are arranged to reach 40K and 4K respectively, due to the air pressure difference, high-purity helium entering the first-stage cold head for heat exchange can be subjected to heat exchange to reach 40K, then enters a second-stage cold head heat exchanger to be subjected to heat exchange to reach 3K, and then passes through a low-temperature needle valve, so that the temperature of a low-temperature thermostat is reduced to be between 2 and 3k, and therefore the heat exchange efficiency is improved. Helium subjected to heat exchange is pumped away through the circulating pump for circulation, the low-loss liquid conveying pipe is fixed, and vibration transmitted by the liquefier part can be filtered.

Description

Technical Field

[0001] The utility model relates to the technical field of ultra-low vibration low-temperature system, in particular to a dry type ultra-low vibration closed-cycle low-temperature liquefaction system. Background Art

[0002] (1) With the advancement of science and technology, low temperature and low vibration have become indispensable auxiliary technologies for scientific experiments such as physics, chemistry, materials, quantum, and superconductivity. There are two main types of low temperature cooling devices: the first type uses refrigerant refrigeration, that is, storing liquid helium in a container, or continuously transporting liquid helium through a pipeline to the part that needs to be cooled; the second type uses closed-cycle refrigeration. The refrigerators mainly include GM refrigerators and pulse tube refrigerators;

[0003] (2) Since liquid helium is a non-renewable resource, expensive, and dependent on imports, cooling has always been done by transferring liquid helium, which is very costly and cannot be used for long-term experimental testing;

[0004] (3) Using GM refrigerator / pulse tube refrigerator to directly cool the sample causes too much vibration and cannot meet the use conditions of scientific researchers;

[0005] (4) Throttling expansion technology is also called Joule-Thomson (JT) expansion, which is the process of adiabatic expansion of a fluid under higher pressure through a throttle valve toward a lower pressure. According to the principles of thermodynamics, pressure will cause temperature changes, also known as the JT effect. When the ambient temperature of helium is higher than the Joule-Thomson transition temperature, it exhibits a positive JT effect, that is, the gas temperature increases as the pressure decreases; when the ambient temperature of helium is lower than the Joule-Thomson transition temperature, it exhibits a negative JT effect, that is, the gas temperature decreases as the pressure decreases. The use of throttling expansion technology can obtain ultra-low temperature conditions of about 2K using a 4K refrigerator commonly used in the prior art without consuming a large amount of liquid helium. However, there is no method or device for achieving ultra-low temperature using throttling expansion technology in the prior art. Utility Model Content

[0006] Based on the technical problems of the existing cryogenic liquefaction system, the utility model proposes a dry ultra-low vibration closed-cycle cryogenic liquefaction system.

[0007] The utility model proposes a dry type ultra-low vibration closed-cycle low-temperature liquefaction system, comprising a liquefier part, a low-loss liquid infusion pipe part, a low-temperature thermostat part and a circulating gas circuit part, wherein the liquefier part is connected to the low-temperature thermostat part through the low-loss liquid infusion pipe part, and the low-temperature thermostat part is connected to the liquefier part through the circulating gas circuit part;

[0008] The liquefier includes a refrigerator, and the refrigerator is installed through the inside of the vacuum chamber via a shock-absorbing bellows;

[0009] The refrigerator includes a vacuum extraction port, the lower end of the vacuum extraction port is fixedly connected to the upper end of the vacuum chamber through a standard clamp, the refrigerator also includes a vacuum explosion-proof valve, the vacuum explosion-proof valve is fixedly installed on the upper end of the vacuum chamber through epoxy resin glue, a low-temperature needle valve is arranged inside the vacuum chamber, the low-temperature needle valve includes a needle valve handle, the needle valve handle is fixedly installed on the upper end of the vacuum chamber, the low-temperature needle valve is fixedly connected to the lower surface of the secondary cold plate, the upper surface of the secondary cold plate is fixedly connected to the lower end of the secondary cold head heat exchanger through a hexagon socket screw, the upper end of the secondary cold head heat exchanger is brazed with the lower end of the primary cold head heat exchanger through a 3.2mm stainless steel capillary, the upper end of the primary cold head heat exchanger is fixedly connected to the upper end of the cold screen through a hexagon socket screw, the upper end of the cold screen is fixedly connected to the lower end of the primary cold head through a hexagon socket screw, and the primary cold head is fixedly connected to the secondary cold head through a pipeline;

[0010] The secondary cold plate, the secondary cold head heat exchanger, the primary cold head heat exchanger, the cold shield, the primary cold head and the secondary cold head are all arranged inside the vacuum chamber;

[0011] The low-loss infusion tube part comprises a low-loss infusion tube and a low-loss infusion tube fixing frame, and the low-loss infusion tube is fixedly installed on the low-loss infusion tube fixing frame;

[0012] The cryostat portion includes a cryostat and a first metal bellows;

[0013] The circulating gas circuit comprises a circulating pump, a second metal bellows, a third metal bellows, a cut-off valve, a fourth metal bellows and a helium tank, and the circulating pump circulates the high-purity helium after heat treatment.

[0014] Preferably, the cryogenic needle valve is fixedly connected to the inside of the vacuum chamber by argon arc welding, and the cryogenic needle valve is regulated by the needle valve handle.

[0015] Through the above technical solution, the needle valve handle is used to realize the adiabatic expansion process, so that the 3k low-temperature helium gas passing through the cryogenic needle valve after liquefaction will be cooled to 2k.

[0016] Preferably, the low-loss infusion tube is fixedly connected to the vacuum chamber and the low-temperature thermostat respectively through a standard clamp, and the low-loss infusion tube fixing frame is fixedly installed on the ground.

[0017] Through the above technical solution, the 2k low-temperature helium cooled by the low-temperature needle valve reaches the low-temperature thermostat through the low-loss infusion tube for heat exchange, so that the temperature of the low-temperature thermostat slowly drops to between 2-3k, and the low-loss infusion tube is fixed by the low-loss infusion tube fixing frame. At this time, the vibration transmitted from the liquefier part will be filtered, thus achieving ultra-low vibration.

[0018] Preferably, the air inlet of the circulation pump is fixedly connected to the low-temperature thermostat through the first metal bellows, and the refrigerator includes a refrigeration air inlet, which is fixedly connected to the air outlet of the circulation pump through the second metal bellows.

[0019] Through the above technical solution, the helium after heat exchange inside the cryostat is pumped away by the circulation pump, and then enters the second metal bellows from the outlet of the circulation pump, and then enters the primary cold head heat exchanger and the secondary cold head heat exchanger inside the vacuum chamber through the refrigeration air inlet again. In this way, a complete closed-loop cooling system is realized.

[0020] Preferably, the middle part of the second metal bellows is fixedly connected to one end of the third metal bellows, the other end of the third metal bellows is fixedly connected to one end of the isolation valve, the other end of the isolation valve is fixedly connected to one end of the fourth metal bellows, the other end of the fourth metal bellows is welded to the upper surface of the helium tank by argon arc, the upper surface of the helium tank is welded with a 1 / 4 joint stainless steel pipe by argon arc, and one end of the 1 / 4 joint stainless steel pipe is fixedly connected to a positive and negative pressure gauge by epoxy resin glue.

[0021] Through the above technical solution, the isolating valve is controlled to control whether helium enters the third metal bellows, and the positive and negative pressure gauges can measure the pressure in the helium tank in real time, provide an alarm for abnormal pressure or leakage, and help prevent potential safety risks, such as container rupture or leakage caused by excessive pressure.

[0022] The beneficial effects of the present invention are:

[0023] 1. The vacuum extraction port on the refrigerator is fixedly installed on the upper part of the vacuum chamber through a KF25 standard clamp to evacuate the inner vacuum of the vacuum chamber. The GM refrigerator is fixedly installed on the upper part of the vacuum chamber through a shock-absorbing bellows. The shock-absorbing bellows can reduce the vibration generated when the refrigerator is working. The vacuum explosion-proof valve is glued to the upper end of the vacuum chamber with epoxy resin glue. In order to prevent safety accidents caused by helium leakage, one end of the needle valve handle is fixedly installed on the vacuum chamber to realize the adiabatic expansion process so that the temperature of the liquefied helium reaches less than 2K.

[0024] 2. By setting up the GM refrigerator, wait until the primary cold head and the secondary cold head reach 40K and 4K respectively, open the isolation valve, low-temperature needle valve, and circulation pump. After turning on the circulation pump, due to the pressure difference, the high-purity helium in the helium tank enters the primary cold head heat exchanger through the refrigeration air inlet. The high-purity helium entering the primary cold head heat exchanger will be heat exchanged to 40k, and then the 40k high-purity helium enters the secondary cold head heat exchanger. The high-purity helium entering the secondary cold head heat exchanger will be heat exchanged to 3k. The 3K low-temperature helium passing through the low-temperature needle valve will be cooled to 2k. The 2k low-temperature helium reaches the low-temperature thermostat through a low-loss infusion tube for heat exchange, so that the temperature of the low-temperature thermostat slowly drops until it drops to between 2-3k. The heat exchanged helium is pumped away by the circulation pump, and then enters the KF16 metal bellows from the outlet of the circulation pump, and then enters the primary cold head heat exchanger and the secondary cold head heat exchanger through the refrigeration air inlet again, thereby realizing a complete set of closed-loop cooling system.

[0025] 3. A low-loss infusion tube fixing frame is fixedly installed on the ground to clamp the low-loss infusion tube between the vacuum chamber and the low-temperature thermostat. At this time, the vibration transmitted from the liquefier part will be filtered, thereby achieving ultra-low vibration. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a schematic diagram of a dry type ultra-low vibration closed cycle cryogenic liquefaction system proposed by the utility model;

[0027] Figure 2 This is a top view of the refrigerator structure of a dry ultra-low vibration closed-cycle cryogenic liquefaction system proposed by the utility model.

[0028] In the figure: 1. vacuum extraction port; 2. refrigerator; 3. vacuum explosion-proof valve; 4. needle valve handle; 5. shock-absorbing bellows; 6. vacuum chamber; 7. primary cold head; 8. cold screen; 9. secondary cold head; 10. secondary cold plate; 11. low-temperature needle valve; 12. primary cold head heat exchanger; 13. secondary cold head heat exchanger; 14. low-loss infusion tube; 15. low-loss infusion tube fixing bracket; 16. low-temperature thermostat; 17. first metal bellows; 18. circulation pump; 19. second metal bellows; 20. third metal bellows; 21. isolation valve; 22. fourth metal bellows; 23. helium tank; 24. 1 / 4 joint stainless steel pipe; 25. positive and negative pressure gauges; 26. refrigeration air inlet. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention will be described clearly and completely below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all of the embodiments.

[0030] Reference Figure 1-Figure 2 A dry type ultra-low vibration closed-cycle low-temperature liquefaction system comprises a liquefier part, a low-loss liquid infusion pipe part, a low-temperature thermostat part and a circulating gas circuit part, wherein the liquefier part is connected to the low-temperature thermostat part through the low-loss liquid infusion pipe part, and the low-temperature thermostat part is connected to the liquefier part through the circulating gas circuit part; the liquefier comprises a GM refrigerator 2, and the GM refrigerator 2 is installed through the inside of a vacuum chamber 6 through a shock-absorbing bellows 5;

[0031] The GM refrigerator 2 includes a vacuum extraction port 1, the lower end of which is fixedly connected to the upper end of the vacuum chamber 6 through a standard clamp, and the GM refrigerator 2 also includes a vacuum explosion-proof valve 3, which is fixedly installed on the upper end of the vacuum chamber 6 through epoxy resin glue, and a low-temperature needle valve 11 is arranged inside the vacuum chamber 6, and the low-temperature needle valve 11 includes a needle valve handle 4, and the needle valve handle 4 is fixedly installed on the upper end of the vacuum chamber 6, and the low-temperature needle valve 11 is fixedly connected to the lower surface of the secondary cold plate 10, and the upper surface of the secondary cold plate 10 is fixedly connected to the lower end of the secondary cold head heat exchanger 13 through a hexagon socket screw, and the upper end of the secondary cold head heat exchanger 13 is brazed with the lower end of the primary cold head heat exchanger 12 through a 3.2mm stainless steel capillary, and the upper end of the primary cold head heat exchanger 12 is fixedly connected to the upper end of the cold screen 8 through a hexagon socket screw, and the upper end of the cold screen 8 is fixedly connected to the lower end of the primary cold head 7 through a hexagon socket screw, and the primary cold head 7 is fixedly connected to the secondary cold head 9 through a pipeline;

[0032] The secondary cold plate 10, the secondary cold head heat exchanger 13, the primary cold head heat exchanger 12, the cold shield 8, the primary cold head 7 and the secondary cold head 9 are all arranged inside the vacuum chamber 6;

[0033] The low-loss infusion tube part includes a low-loss infusion tube 14 and a low-loss infusion tube fixing frame 15, and the low-loss infusion tube 14 is fixedly installed on the low-loss infusion tube fixing frame 15;

[0034] The cryostat part includes a cryostat 16 and a first metal bellows 17, and the first metal bellows 17 is 90 degrees to the low-loss liquid infusion tube 14;

[0035] The circulating gas circuit includes a circulating pump 18, a second metal bellows 19, a third metal bellows 20, a cut-off valve 21, a fourth metal bellows 22 and a helium tank 23. The circulating pump 18 circulates the high-purity helium after heat treatment.

[0036] In this embodiment, in order to cool the helium and provide a low-temperature environment, it is also possible to prevent helium leakage and safety accidents;

[0037] Specifically, the vacuum extraction port 1 on the GM refrigerator 2 is fixedly installed on the upper part of the vacuum chamber 6 through a KF25 standard clamp to evacuate the inner vacuum of the vacuum chamber 6. The GM refrigerator 2 is fixedly installed on the upper part of the vacuum chamber 6 through a shock-absorbing bellows 5. The shock-absorbing bellows 5 can reduce the vibration generated when the GM refrigerator 2 is working. The vacuum explosion-proof valve 3 is glued to the upper end of the vacuum chamber 6 through epoxy resin glue. In order to prevent safety accidents caused by helium leakage, one end of the needle valve handle 4 is fixedly installed on the vacuum chamber 6 to realize the adiabatic expansion process so that the temperature of the liquefied helium reaches less than 2K.

[0038] In this embodiment, in order to allow the helium to exchange heat in the liquefier, the helium can be cooled;

[0039] Specifically, a cryogenic needle valve 11 is provided inside the vacuum chamber 6. The cryogenic needle valve 11 includes a needle valve handle 4. The needle valve handle 4 is fixedly mounted on the upper end of the vacuum chamber 6. The needle valve handle 4 is used to realize the process of adiabatic expansion so that the temperature of the liquefied helium reaches less than 2K, and the needle valve handle 4 is used to regulate the cryogenic needle valve 11. The cryogenic needle valve 11 is fixedly mounted inside the vacuum chamber 6 by argon arc welding. The cryogenic needle valve 11 is fixedly connected to the lower surface of the secondary cold plate 10. The upper surface of the secondary cold plate 10 is connected to the lower end of the secondary cold head heat exchanger 13 by a hexagon socket screw. Fixed connection, the upper end of the secondary cold head heat exchanger 13 is brazed and connected to the lower end of the primary cold head heat exchanger 12 through a 3.2 mm stainless steel capillary, the upper end of the primary cold head heat exchanger 12 is fixedly connected to the upper end of the cold screen 8 through a hexagon socket screw, the upper end of the cold screen 8 is fixedly connected to the lower end of the primary cold head 7 through a hexagon socket screw, the primary cold head 7 is fixedly connected to the secondary cold head 9 through a pipeline, the secondary cold plate 10, the secondary cold head heat exchanger 13, the primary cold head heat exchanger 12, the cold screen 8, the primary cold head 7 and the secondary cold head 9 are all arranged inside the vacuum chamber 6.

[0040] In this embodiment, in order to achieve a complete set of closed-loop cooling for the entire system;

[0041] Specifically, by setting up the GM refrigerator 2, wait until the primary cold head 7 and the secondary cold head 9 reach 40K and 4K respectively, open the isolation valve 21, the low-temperature needle valve 11, and the circulation pump 18. After the circulation pump 18 is turned on, due to the pressure difference, the high-purity helium in the helium tank 23 enters the primary cold head heat exchanger 12 through the refrigeration air inlet 26. The high-purity helium entering the primary cold head heat exchanger 12 will be heat exchanged to 40K, and then the 40K high-purity helium enters the secondary cold head heat exchanger 13. The high-purity helium entering the secondary cold head heat exchanger 13 will be heat exchanged to 3K. The 3K low-temperature helium of the low-temperature needle valve 11 will be cooled to 2K, and the 2K low-temperature helium reaches the low-temperature thermostat 16 through the low-loss infusion tube 14 to exchange heat with it, so that the temperature of the low-temperature thermostat 16 slowly drops until it drops to between 2-3K. The helium after heat exchange is pumped away by the circulating pump 18, and then enters the second metal bellows 19 of KF16 from the outlet of the circulating pump 18, and then enters the first-stage cold head heat exchanger 12 and the second-stage cold head heat exchanger 13 through the refrigeration air inlet 26 again, thereby realizing a complete closed-loop cooling system.

[0042] In this embodiment, in order to make the low temperature experimental environment vibration less than 15nm;

[0043] Specifically, a low-loss infusion tube 14 is fixed to the lower end of the vacuum chamber 6 through a KF50 standard clamp, and a low-loss infusion tube fixing frame 15 is fixedly installed on the ground to clamp the low-loss infusion tube 14 between the vacuum chamber 6 and the low-temperature thermostat 16. At this time, the vibration transmitted from the liquefier part will be filtered.

[0044] Working principle: In order to lower the experimental temperature, turn on the GM refrigerator 2, wait until the temperatures of the first-stage cold head 7 and the second-stage cold head 9 in the GM refrigerator 2 reach 40K and 4K respectively, and then open the isolation valve 21, the low-temperature needle valve 11 and the circulation pump 18;

[0045] After the circulation pump 18 is turned on, due to the pressure difference, the high-purity helium in the helium tank 23 enters the primary cold head heat exchanger 12 inside the vacuum chamber 6 through the refrigeration air inlet 26 on one side of the liquefier. One side of the upper end of the primary cold head heat exchanger 12 is fixedly installed with the upper end of the cold screen 8, and the other side of the upper end of the cold screen 8 is fixedly installed with the lower end of the primary cold head 7. Therefore, the high-purity helium entering the primary cold head heat exchanger 12 will be heat-exchanged to the temperature of 40k of the primary cold head 7. The upper end of the secondary cold head heat exchanger 13 is brazed and connected to the lower end of the primary cold head heat exchanger 12 through a 3.2mm stainless steel capillary. The 40k high-purity helium enters the secondary cold head heat exchanger 13 again. The high-purity helium entering the secondary cold head heat exchanger 13 will be heat-exchanged to 3k. At this time, the 3K low-temperature helium passes through the low-temperature needle valve 11. Due to the throttling expansion technology, it is also called Joule-Thomson (JT, Joule-Thomson) omson) expansion, the 3K low-temperature helium passing through the low-temperature needle valve 11 will be cooled to 2k, and the 2k low-temperature helium after heat exchange reaches the low-temperature thermostat 16 through the low-loss infusion tube 14 to exchange heat with it. The low-temperature thermostat 16 is fixedly connected to one end of the circulation pump 18 through the KF25 first metal bellows 17, and the KF16 second metal bellows 19 at the other end of the circulation pump 18 is fixedly connected to the refrigeration air inlet 26 on the liquefier through the KF16 standard clamp. The helium in the low-temperature thermostat 16 that has undergone heat exchange is then pumped away through the circulation pump 18, and then enters the KF16 second metal bellows 19 from the outlet of the circulation pump 18, and then enters the first-stage cold head heat exchanger 12 and the second-stage cold head heat exchanger 13 inside the liquefier through the refrigeration air inlet 26 on one side of the liquefier for circulation, thereby realizing a complete set of closed-loop cooling system;

[0046] The low-loss infusion tube fixing frame 15 is fixedly installed on the ground and is used to clamp the low-loss infusion tube 14 between the liquefier and the cryostat 16. At this time, the vibration transmitted from the liquefier part will be filtered, thus achieving ultra-low vibration;

[0047] This patent adopts an external GM refrigerator 2 and utilizes the special structure of helium circulation to achieve ultra-low temperature and ultra-low vibration experimental conditions.

[0048] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes within the technical scope disclosed by the present invention according to the technical scheme and the utility model concept of the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A dry type ultra-low vibration closed cycle low temperature liquefaction system, comprising a liquefier part, a low loss liquid delivery pipe part, a low temperature thermostat part and a circulating gas circuit part, characterized in that: The liquefier portion is connected to the cryostat portion via the low-loss liquid delivery pipe portion, and the cryostat portion is connected to the liquefier portion via the circulating gas path portion; The liquefier comprises a refrigerator (2), and the refrigerator (2) is installed through the inside of the vacuum chamber (6) via a shock-absorbing bellows (5); The refrigerator (2) comprises a vacuum extraction port (1), the lower end of the vacuum extraction port (1) being fixedly connected to the upper end of the vacuum chamber (6) via a standard clamp, the refrigerator (2) further comprising a vacuum explosion-proof valve (3), the vacuum explosion-proof valve (3) being fixedly mounted on the upper end of the vacuum chamber (6) via epoxy resin glue, a low-temperature needle valve (11) being arranged inside the vacuum chamber (6), the low-temperature needle valve (11) comprising a needle valve handle (4), the needle valve handle (4) being fixedly mounted on the upper end of the vacuum chamber (6), the low-temperature needle valve (11) being fixedly connected to the secondary cooling chamber (6) and the low-temperature needle valve (11) being fixedly mounted on the secondary cooling chamber (6). The lower surface of the plate (10), the upper surface of the secondary cold plate (10) is fixedly connected to the lower end of the secondary cold head heat exchanger (13) through a hexagon socket screw, the upper end of the secondary cold head heat exchanger (13) is brazed to the lower end of the primary cold head heat exchanger (12) through a 3.2 mm stainless steel capillary, the upper end of the primary cold head heat exchanger (12) is fixedly connected to the upper end of the cold screen (8) through a hexagon socket screw, the upper end of the cold screen (8) is fixedly connected to the lower end of the primary cold head (7) through a hexagon socket screw, and the primary cold head (7) is fixedly connected to the secondary cold head (9) through a pipeline; The secondary cold plate (10), the secondary cold head heat exchanger (13), the primary cold head heat exchanger (12), the cold shield (8), the primary cold head (7) and the secondary cold head (9) are all arranged inside the vacuum chamber (6); The low-loss infusion tube part comprises a low-loss infusion tube (14) and a low-loss infusion tube fixing frame (15), wherein the low-loss infusion tube (14) is fixedly mounted on the low-loss infusion tube fixing frame (15); The cryostat part comprises a cryostat (16) and a first metal bellows (17), and the first metal bellows (17) is at a 90-degree angle with the low-loss liquid infusion tube (14); The circulating gas circuit comprises a circulating pump (18), a second metal bellows (19), a third metal bellows (20), a blocking valve (21), a fourth metal bellows (22) and a helium tank (23). The circulating pump (18) circulates the high-purity helium that has undergone heat treatment.

2. A dry type ultra-low vibration closed cycle cryogenic liquefaction system according to claim 1, characterized in that: The low-temperature needle valve (11) is fixedly connected to the inside of the vacuum chamber (6) by argon arc welding, and the low-temperature needle valve (11) is regulated by the needle valve handle (4).

3. A dry type ultra-low vibration closed cycle cryogenic liquefaction system according to claim 1, characterized in that: The low-loss infusion tube (14) is fixedly connected to the vacuum chamber (6) and one end of the low-temperature thermostat (16) respectively through a standard clamp, and the low-loss infusion tube fixing frame (15) is fixedly installed on the ground.

4. A dry type ultra-low vibration closed cycle cryogenic liquefaction system according to claim 1, characterized in that: The air inlet of the circulation pump (18) is fixedly connected to one end of the low-temperature thermostat (16) through the first metal bellows (17), and the refrigerator (2) includes a refrigeration air inlet (26), which is fixedly connected to the air outlet of the circulation pump (18) through the second metal bellows (19).

5. The dry type ultra-low vibration closed cycle cryogenic liquefaction system according to claim 1, characterized in that: The middle portion of the second metal bellows (19) is fixedly connected to one end of the third metal bellows (20), the other end of the third metal bellows (20) is fixedly connected to one end of the isolation valve (21), the other end of the isolation valve (21) is fixedly connected to one end of the fourth metal bellows (22), the other end of the fourth metal bellows (22) is welded to the upper surface of the helium tank (23) by argon arc welding, the upper surface of the helium tank (23) is welded with a 1 / 4 joint stainless steel pipe (24) by argon arc welding, and one end of the 1 / 4 joint stainless steel pipe (24) is fixedly connected to a positive and negative pressure gauge (25) by epoxy resin glue.

Images