JT throttling refrigeration system driven by superconducting direct-current linear compressor

Abstract

The invention relates to the technical field of mechanical refrigeration, and provides a JT throttling refrigeration system driven by a superconducting direct-current linear compressor, which comprises a precooling refrigerator, a cold head and a compressor shell in contact with the cold head, the superconducting linear motor and the compression unit are both arranged in the compressor shell; the heat exchanger is used for pre-cooling the high-pressure incoming flow gas by utilizing the backflow cold gas; the throttling valve penetrates through the heat exchanger and communicates with the high-pressure end of the compression unit; one end of the evaporator is connected with the throttle valve, and the other end of the evaporator penetrates through the heat exchanger and is connected with the low-pressure end of the compression unit; the vacuum cover is used for vacuum heat insulation and heat radiation shielding; the superconducting linear motor, the compression unit, the cold head, the heat exchanger, the throttling valve and the evaporator are all located in the vacuum cover. The superconducting linear motor is adopted for driving, high current capacity is achieved, Joule heat loss is eliminated, higher compression efficiency is obtained, the compression unit is miniaturized, low in power consumption and high in reliability, and the output performance of the compression unit is improved.

Description

Technical Field

[0001] The present invention relates to the technical field of mechanical refrigeration, and in particular to a JT throttling refrigeration system driven by a superconducting DC linear compressor. Background Art

[0002] A precooling refrigerating machine is a refrigeration device that adds a precooling link in the refrigeration cycle. Usually, a fluid or refrigeration system with a lower temperature is used to first pre-cool the object to be cooled or the refrigerant, and then the temperature is further reduced by the main refrigeration system to achieve a lower refrigeration temperature or improve the refrigeration efficiency.

[0003] As Figure 1 shown, it is a pre-cooling refrigerating machine in the prior art. The pre-cooling is provided by a two-stage precooler A01. The helium refrigerant is compressed by a compressor to form a high-pressure gas. The high-pressure side gas is cooled by the refluxing low-pressure side gas when flowing through the three-stage countercurrent partition heat exchangers A09, A10, and A11, and is cooled to the corresponding pre-cooling temperature by the cold heads A14 and A15 of the precooler when flowing through the two-stage precooling heat exchangers A12 and A13. Subsequently, it is cooled by a throttle valve A17 to generate a refrigeration effect and reduced to a low pressure. The low-pressure gas absorbs the heat load through the cold head heat exchanger A18 to provide refrigeration capacity, and finally flows through the low-pressure sides of the three-stage countercurrent partition heat exchangers A11, A10, and A09 in sequence and returns to the compressor.

[0004] The compressor is generally a linear compressor, which includes a linear drive mechanism A02, a cylinder A04, and a piston A05. The linear drive mechanism A02 drives the connecting rod A03 and the piston A05 to reciprocate in the cylinder A04, and forms a one-way flow of gas by alternately opening and closing the intake valve plate A06 and the exhaust valve plate A07.

[0005] However, since the compressor is in a normal temperature environment, the cold heads of the precooler and the heat exchangers of the JT throttling refrigerating machine are in a vacuum low-temperature environment and are installed inside the vacuum cover A08. The compressor and the JT throttling components are connected by pipelines, and the efficiency of the compressor is low. Summary of the Invention

[0006] The present invention provides a JT throttling refrigeration system driven by a superconducting DC linear compressor to solve the defect of low compressor efficiency in the prior art, achieve high current capacity, and at the same time eliminate Joule heat loss, thereby obtaining a higher compression efficiency.

[0007] The present invention provides a JT throttling refrigeration system driven by a superconducting DC linear compressor, including: A precooling refrigerating machine with a cold head; A compressor housing in contact with the cold head; A superconducting linear motor and a compression unit are both disposed inside the compressor housing, and the compression unit outputs high-pressure gas working medium under the drive of the superconducting linear motor; wherein, the coil of the superconducting linear motor is made of superconducting material; A heat exchanger for precooling the high-pressure incoming gas by using the reflux cold gas; A throttle valve that penetrates through the heat exchanger and is connected to the high-pressure end of the compression unit; An evaporator, one end of which is connected to the throttle valve, and the other end of the evaporator penetrates through the heat exchanger and is connected to the low-pressure end of the compression unit; A vacuum cover for vacuum insulation and shielding thermal radiation; and the superconducting linear motor, the compression unit, the cold head, the heat exchanger, the throttle valve and the evaporator are all located inside the vacuum cover.

[0008] A JT throttling refrigeration system driven by a superconducting DC linear compressor according to the present invention, wherein the superconducting linear motor includes: A superconducting coil made of superconducting material, which can perform linear reciprocating motion after applying an alternating voltage; A permanent magnet for providing a continuous and stable magnetic field; A yoke iron connected to the permanent magnet for guiding the magnetic force lines to form a closed loop; A coil bracket for connecting the superconducting coil and the compression unit, so that the compression unit moves linearly and reciprocally along with the superconducting coil.

[0009] A JT throttling refrigeration system driven by a superconducting DC linear compressor according to the present invention, wherein the superconducting linear motor further includes: A leaf spring group, the outer ring of which is connected to the fixed end, and the center of which is connected to the piston of the compression unit, and the leaf spring group is used to provide support for the compression unit to perform oscillating linear motion in the axial direction.

[0010] A JT throttling refrigeration system driven by a superconducting DC linear compressor according to the present invention, wherein the compression unit includes: A piston connected to both the coil bracket and the leaf spring group; A cylinder for providing a space for compressing and throttling the working medium during the reciprocating motion of the piston; An intake valve and an exhaust valve are disposed on the cylinder, and both the intake valve and the exhaust valve are alternately opened and closed based on the gas pressure difference between the inside of the cylinder and the inlet and outlet pipelines; the high-pressure gas discharged by the exhaust valve penetrates through the heat exchanger and is connected to one end of the throttle valve, and the gas refluxed by the intake valve penetrates through the heat exchanger and is connected to one end of the evaporator.

[0011] A JT throttling refrigeration system driven by a superconducting DC linear compressor according to the present invention further includes: An elastic cold chain is arranged between the cold head and the compressor housing.

[0012] In a JT throttling refrigeration system driven by a superconducting DC linear compressor according to the present invention, the precooling refrigerator adopts a refrigeration method with two-stage or multi-stage cold heads, and the refrigeration temperature of the last-stage cold head is lower than the temperature required for the normal operation of the superconducting coil.

[0013] In a JT throttling refrigeration system driven by a superconducting DC linear compressor according to the present invention, the superconducting linear motors are used in pairs and arranged back-to-back linearly, and the two superconducting linear motors are driven by the same voltage and move in opposite directions.

[0014] In a JT throttling refrigeration system driven by a superconducting DC linear compressor according to the present invention, the heat exchanger adopts a coaxial spiral tube structure.

[0015] In a JT throttling refrigeration system driven by a superconducting DC linear compressor according to the present invention, the evaporator adopts a slit-type, spiral tube-type, pin fin-type or porous filling-type evaporator.

[0016] In a JT throttling refrigeration system driven by a superconducting DC linear compressor according to the present invention, the vacuum cover adopts a vacuum multi-layer shell structure.

[0017] In the JT throttling refrigeration system driven by a superconducting DC linear compressor provided by the present invention, the compression unit is arranged at a low temperature, which increases the density of the working fluid, reduces the compression work, and thus improves the system efficiency of the refrigerator; the use of a superconducting linear motor drive realizes a high current capacity and eliminates Joule heat loss at the same time, thereby obtaining a higher compression efficiency. At the same time, the whole machine has the advantages of miniaturization, low power consumption and high reliability, improving the system efficiency of the refrigerator. Description of the Drawings

[0018] In order to more clearly illustrate the technical solutions in the present invention or the prior art, the following will briefly introduce the drawings required for use in the description of the embodiments or the prior art. Obviously, the drawings in the following description are some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0019] Figure 1 is a schematic structural diagram of a JT throttling refrigeration system in the prior art.

[0020] Figure 2 is a schematic structural diagram of a JT throttling refrigeration system driven by a superconducting DC linear compressor provided by the present invention.

[0021] Reference Numerals: 1. Pre-cooling refrigerator; 2. Cold head; 3. Compressor housing; 4. Superconducting linear motor; 41. Superconducting coil; 42. Permanent magnet; 43. Yoke iron; 44. Coil bracket; 45. Leaf spring group; 5. Compression unit; 51. Piston; 52. Cylinder; 53. Intake valve; 54. Exhaust valve; 6. Heat exchanger; 7. Throttle valve; 8. Evaporator; 9. Vacuum cover; 10. Elastic cold chain. Detailed implementation mode

[0022] To make the objectives, technical solutions and advantages of the present invention clearer, the technical solutions in the present invention will be clearly and completely described below with reference to the accompanying drawings in the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art based on the embodiments in the present invention without creative efforts shall fall within the protection scope of the present invention.

[0023] In the description of the embodiments of the present invention, it should be noted that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the drawings, and is only for the convenience of describing the embodiments of 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 understood as a limitation to the embodiments of the present invention. In addition, the terms "first", "second", "third" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance.

[0024] The following combines Figure 2 to describe the JT throttling refrigeration system driven by a superconducting DC linear compressor of the present invention.

[0025] The embodiment of the present invention provides a JT throttling refrigeration system driven by a superconducting DC linear compressor, including a pre-cooling refrigerator 1, a cold head 2, a compressor housing 3, a superconducting linear motor 4, a compression unit 5, a heat exchanger 6, a throttle valve 7, an evaporator 8 and a vacuum cover 9.

[0026] Among them, the pre-cooling refrigerator 1 can adopt small cryogenic refrigerators such as GM refrigerators, Stirling refrigerators or pulse tube refrigerators. The pre-cooling refrigerator 1 has a cold head 2, and the compressor housing 3 is in contact with the cold head 2 to pre-cool the compressor housing 3 through the cold head 2.

[0027] The superconducting linear motor 4 and the compression unit 5 form a superconducting DC linear compressor. The superconducting linear motor 4 and the compression unit 5 are both sealed inside the compressor housing 3. The compressor housing 3 is filled with a refrigerating gas working medium at a certain pressure, and the external environment is a vacuum. The coil of the superconducting linear motor 4 is made of superconducting material, which has excellent superconducting characteristics and can drive the compression unit 5 to stably output high-pressure gas working medium.

[0028] The heat exchanger 6 applies the principle of heat exchange and uses the reflux cold gas to pre-cool the high-pressure incoming gas. The high-pressure gas pipeline of the heat exchanger 6 is connected to the intake end of the throttle valve 4. The throttle valve 7 passes through the heat exchanger 6 and is connected to the high-pressure end of the compression unit 5; small holes are opened on the metal plate of the throttle valve 7. When the high-pressure gas working medium passes through the small holes, it will expand and generate a refrigeration effect.

[0029] One end of the evaporator 8 is connected to the throttle valve 7, and the other end of the evaporator 8 passes through the heat exchanger 6 and is connected to the low-pressure end of the compression unit 5. The evaporator 8 is a heat exchanger used to absorb the heat of the target load. The evaporator 8 can absorb the external heat to achieve the refrigeration purpose.

[0030] The vacuum cover 9 is used for vacuum insulation and shielding thermal radiation; and the superconducting linear motor 4, the compression unit 5, the cold head 2, the heat exchanger 6, the throttle valve 7 and the evaporator 8 are all located inside the vacuum cover 9 to minimize the interference of the external environment on the system operation.

[0031] During the actual operation process, for the JT throttle refrigeration system driven by the superconducting DC linear compressor provided by the embodiment of the present invention, first start the precooling refrigerator 1 to precool the superconducting linear motor 4. When the temperature drops to the optimal working temperature of the superconducting linear motor 4, start the superconducting linear motor 4. At this time, the gas is compressed by the compression unit 5 to form high-pressure gas, and then discharged to the throttle valve 7. The throttle valve 7 throttles and cools the high-pressure gas to generate a refrigeration effect, and the gas pressure drops to low pressure accordingly. The low-pressure gas passes through the evaporator 8 and provides cooling capacity by absorbing the heat load. After that, the low-pressure gas flows through the low-pressure side of the heat exchanger 6 and finally returns to the compression unit 5. During this process, the high-pressure gas is further cooled by the reflux low-pressure side gas when flowing through the heat exchanger 6.

[0032] Compared with the traditional refrigeration system, in the embodiment of the present invention, the superconducting linear motor 4 and the compression unit 5 are arranged at low temperature, effectively improving the density of the working fluid, reducing the energy loss during the compression process, reducing the compression work, and thus improving the system efficiency of the refrigeration.

[0033] Driven by the superconducting linear motor 4, it realizes high current capacity, and at the same time eliminates the Joule heat loss, thereby obtaining higher compression efficiency. At the same time, the whole machine has the advantages of miniaturization, low power consumption and high reliability, improving the system efficiency of the refrigerator.

[0034] In some feasible embodiments of the present invention, the superconducting linear motor 4 includes a superconducting coil 41, a permanent magnet 42, a yoke 43, and a coil bracket 44. The superconducting coil 41 is a moving component of the superconducting linear motor 4. Made of superconducting materials, it can perform linear reciprocating motion after applying an alternating voltage. The superconducting coil is wound with other superconducting wires such as MgB2, Bi2223, or YBCO, and the operating temperature is below 30K. These superconducting wires have zero resistance characteristics at the above operating temperatures. Compared with traditional coils, it not only improves the motor efficiency, but also reduces the additional heat dissipation requirements, helps to maintain the low-temperature environment inside the system, and further reduces the overall energy consumption of the system. At the same time, as a linear reciprocating motion component, the superconducting coil 41 can generate a strong magnetic field under the drive of an alternating voltage, interact with the magnetic field of the permanent magnet 42, and provide a stable and strong driving force for the compression unit 5 to ensure the efficient operation of the system.

[0035] The permanent magnet 42 is used to provide a continuous and stable magnetic field and is an exciting component of the superconducting linear motor 4. It is usually made of permanent magnetic materials such as praseodymium iron boron, neodymium iron boron, or samarium cobalt. These materials have the characteristics of high remanence and high coercivity and can generate a stable and strong magnetic field. The stable exciting magnetic field makes the operation of the superconducting linear motor 4 more stable, reduces the vibration and noise during the operation of the motor, and improves the reliability and stability of the motor. In addition, the permanent magnet 42 does not require an additional exciting power supply, reducing the complexity and energy consumption of the system.

[0036] The yoke 43 is connected to the permanent magnet 42 and is used to guide the magnetic force lines to form a closed loop. By reasonably designing the shape and material of the yoke 43, the magnetic circuit distribution can be optimized, magnetic leakage can be reduced, and the efficiency of the magnetic circuit can be improved. The efficient magnetic circuit can make full use of the magnetic field of the superconducting linear motor 4, enhance the interaction force between the superconducting coil 41 and the permanent magnet 42, and further improve the performance of the motor.

[0037] The coil bracket 44 is used to connect the superconducting coil 41 and the compression unit 5, so that the compression unit 5 moves linearly back and forth with the superconducting coil 41, enabling the compression unit 5 to respond more precisely to the movement of the superconducting coil 41 and improving the compression performance and stability of the compression unit 5.

[0038] In some feasible embodiments of the present invention, the superconducting linear motor 4 further includes a leaf spring group 45. The outer ring is connected to the fixed end, and the center is connected to the compression unit 5. The leaf spring group 45 is used to provide support for the compression unit 5 to perform oscillating linear motion in the axial direction. The leaf spring group 45 has good elastic recovery characteristics and can provide a stable axial support force when the compression unit 5 performs oscillating linear motion. When the superconducting coil 41 drives the compression unit 5 to move, the leaf spring group 45 buffers and cancels part of the impact force and vibration during the movement through its own elastic deformation, ensuring that the compression unit 5 always moves in a straight line along the predetermined axial trajectory. This not only effectively improves the stability of the movement of the compression unit 5, but also enables it to respond more precisely to the movement instructions of the superconducting coil 41, thereby enhancing the stability and reliability of the operation of the entire superconducting linear motor 4 and reducing energy loss and mechanical failures caused by movement deviation.

[0039] In some feasible embodiments of the present invention, the compression unit 5 includes a piston 51, a cylinder 52, an intake valve 53, and an exhaust valve 54.

[0040] The piston 51 is connected to the coil bracket 44 and the center of the leaf spring group 45 to achieve precise and stable reciprocating motion. The cylinder 52 provides a space for compressing and throttling the working medium during the reciprocating motion of the piston 51. The piston 51 is slidably disposed inside the cylinder 52; when the piston 51 compresses the gas in the cylinder 52, the compression ratio of the working stroke is maximized, reducing the efficiency loss caused by the clearance volume.

[0041] The intake valve 53 and the exhaust valve 54 are disposed on the cylinder 52, and both the intake valve 53 and the exhaust valve 54 are alternately opened and closed based on the gas pressure difference between the inside of the cylinder 52 and the inlet and outlet pipelines to achieve the one-way flow of the gas working medium. This not only effectively avoids the backflow and leakage of the gas, ensures the orderly flow of the gas in the system, but also optimizes the gas heat exchange process in the heat exchanger 6. The high-pressure gas discharged by the exhaust valve 54 passes through the heat exchanger 6 and is connected to one end of the throttle valve 7, and the gas flowing back through the intake valve 53 passes through the heat exchanger 6 and is connected to one end of the evaporator 8.

[0042] In some feasible embodiments of the present invention, an elastic cold chain 10 is further included. The elastic cold chain 10 is disposed between the cold head 2 and the compressor housing 3, and heat transfer and vibration damping are provided for the compressor housing 3 through the elastic cold chain 10. The elastic cold chain 10 provides elastic coupling for the cold head 2. Compared with the traditional heat transfer method, the elastic cold chain 10 can effectively reduce the energy loss during the heat transfer process, ensure that the cold generated by the cold head 2 can be utilized to the maximum extent, and quickly reduce the temperature of the compressor housing 3. This not only helps to maintain the low-temperature working environment of the superconducting linear motor 4 and improve the operating efficiency of the motor, but also indirectly improves the refrigeration performance of the entire refrigeration system, enabling the system to reach the required refrigeration temperature in a shorter time and providing more efficient refrigeration services for users.

[0043] In some feasible embodiments of the present invention, the precooling refrigerator 1 adopts a refrigeration method with a two-stage cold head or a multi-stage cold head, and the refrigeration temperature of the last-stage cold head 2 is lower than the temperature required for the normal operation of the superconducting coil 41. As Figure 1 shown, the precooling refrigerator 1 includes a first-stage cold head and a second-stage cold head. Both the first-stage cold head and the second-stage cold head are installed inside the vacuum chamber 9, and the refrigeration temperature of the second-stage cold head is lower than 30K.

[0044] In some feasible embodiments of the present invention, the superconducting linear motors 4 are used in pairs and arranged linearly back-to-back, and the two superconducting linear motors are driven by the same voltage and move in opposite directions, which can reduce the vibration caused by the movement. On the one hand, it ensures that the components inside the system can work in a stable environment, avoiding problems such as component displacement and connection loosening caused by vibration, thereby ensuring the stability and reliability of the system operation. On the other hand, reducing vibration also helps to reduce noise generation, enabling the refrigeration system to operate in a quieter environment and meeting the application scenarios with high noise control requirements.

[0045] In some feasible embodiments of the present invention, the heat exchanger 6 adopts a coaxial spiral tube structure. By using the countercurrent flow of hot and cold gases, the temperature drop can be accelerated, and the low-temperature cold energy flowing back after throttling can be fully utilized. The heat exchanger 6 can also adopt other types of heat exchangers as long as good heat exchange effects can be achieved.

[0046] In some feasible embodiments of the present invention, the evaporator 8 adopts a slit-type, spiral tube-type, pin fin-type or porous filling-type evaporator, or other types of evaporators can also be used.

[0047] In some feasible embodiments of the present invention, the vacuum chamber 9 adopts a vacuum multi-layer shell structure, which can play the role of vacuum heat insulation and shielding thermal radiation.

[0048] Therefore, for the JT throttling refrigeration system driven by the superconducting DC linear compressor provided by the present invention, the driving unit for driving the working medium circulation of the throttling system is arranged at a low temperature, which increases the density of the working fluid, reduces the compression work, and thus improves the system efficiency of the refrigerator. Driven by the superconducting linear motor 4, it realizes high current capacity and eliminates Joule heat loss at the same time, thereby obtaining higher compression efficiency. At the same time, the whole machine has the advantages of miniaturization, low power consumption and high reliability.

[0049] In summary, the JT throttling refrigeration system driven by the superconducting DC linear compressor provided by the present invention has the characteristics of fast cooling speed, high refrigeration capacity, simple system structure, good reliability and high system efficiency.

[0050] 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 "connected" 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 directly connected or indirectly connected through an intermediate medium. For those of ordinary skill in the art, the specific meanings of the above terms in the embodiments of the present invention can be understood according to specific situations.

[0051] In the description of this specification, the descriptions with reference to terms such as "one embodiment", "some embodiments", "mode", "specific mode", or "some modes" mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or mode are included in at least one embodiment or mode of the embodiments 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 can be combined in a suitable manner in any one or more embodiments or modes. In addition, without conflict, those skilled in the art can combine and combine the different embodiments or modes described in this specification and the features of different embodiments or modes.

[0052] 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 foregoing embodiments, those of ordinary skill in the art should understand that they can still modify the technical solutions recorded in the foregoing embodiments, or perform equivalent replacements for some of the technical features. And these modifications or replacements do not make the essence of the corresponding technical solutions deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A JT throttling refrigeration system driven by a superconducting DC linear compressor, characterized in that: include: A pre-cooling refrigerator (1) having a cold head (2); A compressor housing (3) in contact with the cold head (2); The superconducting linear motor (4) and the compression unit (5) are both arranged inside the compressor housing (3), and the compression unit (5) outputs high-pressure gas working fluid under the drive of the superconducting linear motor (4); wherein the coil of the superconducting linear motor (4) is made of superconducting material; A heat exchanger (6) for precooling the high-pressure incoming gas using the reflux cold gas; a throttle valve (7) passing through the heat exchanger (6) and communicating with the high-pressure end of the compression unit (5); an evaporator (8) for providing and transferring cold energy to a target heat source, one end of which is connected to the throttle valve (7), and the other end of which passes through the heat exchanger (6) and is connected to the low-pressure end of the compression unit (5); The vacuum cover (9) is used for vacuum insulation and shielding thermal radiation; and the superconducting linear motor (4), the compression unit (5), the cold head (2), the heat exchanger (6), the throttle valve (7) and the evaporator (8) are all located in the vacuum cover (9).

2. The JT throttling refrigeration system driven by a superconducting DC linear compressor according to claim 1 is characterized in that: The superconducting linear motor (4) comprises: The superconducting coil (41) is made of superconducting material and can move linearly after an alternating voltage is applied; A permanent magnet (42) for providing a continuous stable magnetic field; A yoke (43) connected to the permanent magnet (42) and used to guide magnetic lines of force to form a closed loop; The coil support (44) is used to connect the superconducting coil (41) and the compression unit (5) so that the compression unit (5) can move linearly back and forth with the superconducting coil (41).

3. The JT throttling refrigeration system driven by a superconducting DC linear compressor according to claim 2, characterized in that: The superconducting linear motor (4) further comprises: The leaf spring group (45) has an outer ring connected to a fixed end and a center connected to the compression unit (5), and the leaf spring group (45) is used to provide support for the compression unit (5) to perform oscillating linear motion in an axial direction.

4. The JT throttling refrigeration system driven by a superconducting DC linear compressor according to claim 3 is characterized in that: The compression unit (5) comprises: A piston (51) connected to the center of the coil support (44) and the leaf spring assembly (45); The cylinder (52) provides a space for compressing and throttling the working medium during the reciprocating motion of the piston (51); An intake valve (53) and an exhaust valve (54) are arranged on the cylinder (52), and both the intake valve (53) and the exhaust valve (54) are alternately opened and closed based on the gas pressure difference between the cylinder (52) and the inlet and outlet pipelines; the high-pressure gas discharged from the exhaust valve (54) passes through the heat exchanger (6) and is connected to one end of the throttle valve (7), and the gas refluxed from the intake valve (53) passes through the heat exchanger (6) and is connected to one end of the evaporator (8).

5. The JT throttling refrigeration system driven by a superconducting DC linear compressor according to any one of claims 1 to 4, characterized in that: Also includes: An elastic cold chain (10) is arranged between the cold head (2) and the compressor casing (3).

6. The JT throttling refrigeration system driven by a superconducting DC linear compressor according to claim 2, characterized in that: The pre-cooling refrigerator (1) adopts a two-stage cold head or a multi-stage cold head cooling method, and the cooling temperature of the last-stage cold head (2) is lower than the temperature required for the normal operation of the superconducting coil (41).

7. The JT throttling refrigeration system driven by a superconducting DC linear compressor according to claim 5, characterized in that: The superconducting linear motors (4) are used in pairs and arranged back to back in a straight line, and the two superconducting linear motors are driven by the same voltage and move in opposite directions.

8. The JT throttling refrigeration system driven by a superconducting DC linear compressor according to claim 5, characterized in that: The heat exchanger (6) adopts a coaxial spiral casing structure.

9. The JT throttling refrigeration system driven by a superconducting DC linear compressor according to claim 5, characterized in that: The evaporator (8) is a slit type, spiral tube type, pin-fin type or porous filling type evaporator.

10. The JT throttling refrigeration system driven by a superconducting DC linear compressor according to claim 5, characterized in that: The vacuum cover (9) adopts a vacuum multi-layer shell structure.

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