Cryostatic device and method for superconducting maglev train

Abstract

Provided are a cryostatic device and method for a superconducting maglev train. The cryostatic device comprises: a conduction device, comprising a conduction outer housing (11), a copper box (12) and low-temperature support rods (13), the copper box (12) being arranged in the conduction outer housing (11), the tops of the low-temperature support rods (13) being fixedly connected to the bottom of the copper box (12), the bottoms of the low-temperature support rods (13) being fixedly connected to the bottom wall of the conduction outer housing (11), a superconducting bulk accommodating cavity being provided at the top of the copper box (12), and a cold energy connecting end (121) being provided at the bottom of the copper box (12); a support device (2), the top of the support device (2) being used for supporting the conduction device, and the bottom of the support device (2) being used for being connected to a train body bogie bottom plate; and a refrigeration device (3), the refrigeration device (3) being provided with a cold energy input end (30), and the cold energy input end (30) being connected to the cold energy connecting end (121).

Description

A low-temperature constant temperature device and method for superconducting magnetic levitation train

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims priority to Chinese patent application number 202311319605.2, filed with the Patent Office of China on October 12, 2023, entitled "A Low-Temperature Constant Temperature Device and Method for Superconducting Magnetoresistive Trains," the entire contents of which are incorporated herein by reference. Technical Field

[0003] The present invention relates to the field of superconducting magnetic levitation, and in particular to a low-temperature constant temperature device and method for a superconducting magnetic levitation train. Background Art

[0004] In the prior art, common maglev train types are mainly divided into three categories: electromagnetic levitation (EMS), electric levitation (EDS), and superconducting maglev (HTS). Superconducting maglev has become a hot topic of extensive research by scholars at home and abroad due to its excellent zero-magnetic resistance characteristics and pinning properties that can provide levitation and guiding force. In existing superconducting maglev devices, the on-board superconducting bulk materials are all installed in an on-board cryostat. The on-board superconducting bulk materials are directly bath-cooled with liquid nitrogen. However, this cooling method requires regular rehydration of the cryostat. After long-term and repeated rehydration operations, the operating efficiency of the train is reduced, and the levitation performance of the superconducting bulk materials is limited. Therefore, there is an urgent need for a cryostat for superconducting maglev trains. On the one hand, it needs to be easy to maintain to ensure the long-term operation of the superconducting maglev train, and on the other hand, it needs to improve the levitation performance of the superconducting bulk materials.

[0005] Summary of the Invention

[0006] The purpose of the present invention is to provide a cryogenic constant temperature device and method for superconducting maglev trains to improve the above-mentioned problems. To achieve the above-mentioned purpose, the technical solutions adopted by the present invention are as follows:

[0007] A cryogenic constant temperature device for a superconducting magnetic levitation train, comprising:

[0008] A conduction device, comprising a conductive outer shell, a copper box, and a low-temperature support rod, wherein the copper box is disposed within the conductive outer shell, the top of the low-temperature support rod is fixedly connected to the bottom of the copper box, the bottom of the low-temperature support rod is fixedly connected to the bottom wall of the conductive outer shell, the top of the copper box is provided with a superconducting block accommodating cavity, and the bottom of the copper box is provided with a cold connection end;

[0009] a supporting device, wherein the top of the supporting device is used to support the conducting device, and the bottom of the supporting device is used to connect to the car body bogie bottom plate; and

[0010] A refrigeration device is provided with a cold input end, and the cold input end is connected to the cold connection end.

[0011] In another aspect, the present invention provides a cryogenic constant temperature method for a superconducting magnetic levitation train, comprising:

[0012] When the refrigeration device is working, the preset cooling capacity is input into the cooling capacity input terminal and conducted through the cooling capacity connection terminal;

[0013] The preset cooling capacity is transferred to the superconducting bulk material accommodating cavity in the copper box, so that the superconducting bulk material in the superconducting bulk material accommodating cavity is cooled;

[0014] According to the temperature feedback of the temperature sensor group, the power of the resistance wire is adjusted to make the superconducting block material reach a preset low temperature value.

[0015] The beneficial effects of the present invention are:

[0016] This device utilizes a refrigeration unit to provide cooling for the superconducting bulk material. The cooling input terminal is connected to the cooling connection terminal to maintain a low temperature environment. The indirect heat conduction between the components reduces heat leakage from the cryostat while maintaining structural strength. Furthermore, this device allows the controlled temperature to be below liquid nitrogen, thereby improving the levitation performance of the superconducting bulk material. The device offers a wide temperature range and controllable temperature regulation, ensuring the long-term operation of superconducting maglev trains. Compared to existing liquid nitrogen cooling systems, this device significantly reduces maintenance costs.

[0017] Other features and advantages of the present invention will be described in the following description, and some will become apparent from the description or be understood by practicing the embodiments of the present invention. The objectives and other advantages of the present invention can be achieved and obtained by the structures particularly pointed out in the written description, claims, and drawings. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the following briefly introduces the drawings required for use in the embodiments. It should be understood that the following drawings only illustrate certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other relevant drawings can be obtained based on these drawings without paying any creative work.

[0019] FIG1 is a schematic diagram of the overall structure of the low-temperature constant temperature device;

[0020] FIG2 is a schematic diagram of the overall structure after the top wall and side walls of the conductive outer shell are removed;

[0021] FIG3 is a schematic diagram of the overall structure when no superconducting block is installed based on FIG2 ;

[0022] FIG4 is a top view of the overall structure after the top wall and side walls of the conductive outer shell are removed and the supporting device is not connected;

[0023] FIG5 is a cross-sectional view taken along line AA of FIG4 ;

[0024] FIG6 is a schematic diagram of an enlarged structure of area B based on FIG5 ;

[0025] FIG7 is a schematic diagram of the arrangement structure of the resistance wire in this embodiment;

[0026] FIG8 is a schematic diagram of the overall structure of the low-temperature constant temperature device after being connected to the vehicle body;

[0027] FIG9 is a schematic diagram of the arrangement structure of the conductive outer shell and the compression rod;

[0028] Markings in the figure: 11. Conductive outer shell; 12. Copper box; 13. Low-temperature support rod; 15. Thermal bridge; 121. Cold connection end; 122. Superconducting block mounting cavity; 2. Support device; 3. Refrigeration device; 30. Cold input end; 31. Cold head mounting base; 32. Adjustment spring; 33. Resistance wire; 41. Transverse fin; 42. Longitudinal fin; 5. Superconducting block; 50. Aviation plug; 51. First vacuum nozzle; 52. Second vacuum nozzle; 71. Car body; 72. Connecting rod; 8. Compression rod. DETAILED DESCRIPTION

[0029] In order to make the purpose, technical solutions and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the drawings in the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. The components of the embodiments of the present invention generally described and shown in the drawings herein can be arranged and designed in various different configurations. Therefore, the following detailed description of the embodiments of the present invention provided in the drawings is not intended to limit the scope of the claimed invention, but merely represents selected embodiments of the present invention. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0030] It should be noted that similar reference numerals and letters represent similar items in the following drawings. Therefore, once an item is defined in one drawing, it does not need to be further defined or explained in subsequent drawings. At the same time, in the description of the present invention, the terms "first", "second", etc. are used only to distinguish the description and should not be understood as indicating or implying relative importance.

[0031] Example 1:

[0032] In this cryogenic constant-temperature device, the principle of the suspension guiding force of the superconducting block is based on the law of electromagnetic induction. The magnetic field source is provided by a Halbach permanent magnet array. The magnetization directions of each permanent magnet are combined in a specific direction to generate a larger magnetic field strength.

[0033] According to the Lorentz force calculation formula, the suspension force on a superconducting block at any position in an external magnetic field is:

[0034] In the above formula, F lev It represents the suspension force on the superconducting bulk at any position in the external magnetic field, J c is the critical current density, B x (δ0) is the tangential magnetic induction intensity of the external magnetic field at the penetration depth δ0 in the superconducting bulk, B x (0) is the tangential magnetic induction intensity of the external magnetic field at the surface of the superconducting bulk material, δ0 is the penetration depth value of the superconducting bulk material, and dv represents the speed of the superconducting bulk material in the external magnetic field.

[0035] It can be seen that the main factors affecting the magnitude of the levitation force are current density and magnetic field strength. The present invention starts from increasing the critical current density. Since the relationship between the internal temperature of the block and the critical current density is:

[0036] In the above formula, J c (T) represents the critical current density when the temperature inside the superconducting bulk is T, J c0 is the critical current density of the superconducting bulk material at the preset initial temperature; T0 is the preset initial temperature of the superconducting bulk material; T c is the preset critical temperature of the superconducting bulk material; T represents the current internal temperature of the superconducting bulk material.

[0037] In the present invention, the preset initial temperature of the superconducting bulk material can be lowered, so that the critical current density is increased, thereby improving the suspension force of the superconducting bulk material.

[0038] In calculating the cooling capacity of the refrigeration device, the present invention mainly considers the radiation heat leakage and the conduction heat leakage, specifically:

[0039] The calculation model of radiation heat leakage is:

[0040] In the above formula, Q red represents the radiation heat leakage between objects; N is the number of layers of multi-layer insulation material; σ represents the Stefan-Boltzmann constant; ε1 and ε2 represent the emissivity of the two objects respectively; A1 represents the surface area of ​​the radiated object; A2 represents the surface area of ​​the radiating object; T1 and T2 represent the temperatures of the radiated object and the radiating object respectively.

[0041] The calculation model of conduction heat leakage is:

[0042] In the above formula, Q cond represents the amount of heat leakage due to conduction; A represents the cross-sectional area of ​​the material; λ represents the thermal conductivity of the low-temperature support rod material; δ represents the length of the low-temperature support rod; Δt is the temperature difference between the hot and cold walls.

[0043] In terms of the cooling capacity setting of the refrigeration device, the cooling capacity setting value is greater than the radiation heat leakage and conduction heat leakage generated by the low-temperature constant temperature device.

[0044] As shown in Figures 1 to 6, a cryogenic constant temperature device for a superconducting maglev train includes:

[0045] A conduction device, comprising a conductive outer shell 11, a copper box 12, and a cryogenic support rod 13. The copper box 12 is disposed within the conductive outer shell 11, and the top of the cryogenic support rod 13 is fixedly connected to the bottom of the copper box 12. The bottom of the cryogenic support rod 13 is fixedly connected to the bottom wall of the conductive outer shell 11. The top of the copper box 12 is provided with a superconducting bulk material accommodating cavity, and the bottom of the copper box 12 is provided with a cold connection terminal 121.

[0046] The inner wall of the conductive outer shell 11 is provided with a silver coating, which is made by a silver deposition method to reduce radiation heat leakage and contact thermal resistance. The conductive outer shell 11 can be made of 304 stainless steel to withstand atmospheric pressure.

[0047] A transverse low-temperature support rod is also provided in the conduction device, which is used to prevent the copper box 12 from contacting the inner wall of the conductive outer shell 11 due to the guiding force of the superconducting block 5, thereby avoiding a large amount of heat leakage.

[0048] The support device 2 has a top portion for supporting the conduction device and a bottom portion for connecting to the vehicle body bogie bottom plate; the support device 2 may be composed of four 7 series aluminum alloys to withstand the suspension guide force transmitted from the low-temperature constant temperature device.

[0049] The refrigeration device 3 is provided with a cold input end 30 , and the cold input end 30 is connected to the cold connection end 121 .

[0050] The refrigeration device 3 can be a Stirling pulse tube refrigerator, with fans provided on both sides of the refrigerator and a heat sink provided on the top of the refrigerator. The refrigerator is provided with a control panel for controlling the cooling output value and output power of the refrigerator.

[0051] In the present low-temperature constant-temperature device, the low-temperature support rod 13 in the conducting device can be made of glass fiber reinforced plastic G-10, which is a mixture of glass fiber and epoxy resin.

[0052] In order to increase the thermal uniformity of the later superconducting block 5 and improve the heat transfer efficiency, a fin device is introduced, which includes a transverse fin 41 and a plurality of longitudinal fins 42. When the transverse fin 41 is arranged along the length direction of the copper box 12, and the plurality of longitudinal fins 42 are vertically connected to the transverse fin 41 in sequence, a plurality of superconducting block installation cavities 122 are formed in the superconducting block accommodating cavity, and the volume of each superconducting block installation cavity 122 is a preset value.

[0053] In order to clarify the installation structure of the superconducting block installation cavity 122, multiple superconducting blocks 5 are introduced, each of the superconducting blocks 5 is connected to each of the superconducting block installation cavities 122 one by one, and the installation height of each superconducting block 5 is flush with the top of the copper box 12.

[0054] In this low-temperature constant temperature device, the introduction of transverse fins 41 and multiple longitudinal fins 42 allows the outer periphery of each superconducting block 5 to be in direct contact with the fins, thereby increasing the thermal uniformity of the superconducting block 5 and improving the heat transfer efficiency. Furthermore, all surfaces of each of the superconducting blocks 5 can be provided with a silver coating. The silver coating is made by a silver deposition method to reduce radiation heat leakage and contact thermal resistance. In addition, each of the superconducting blocks 5 is connected to the superconducting block installation cavity 122 by low-temperature adhesive adhesion. The specifications of the superconducting block can be set to 64×32×13mm.

[0055] To reduce conductive heat leakage, the conductive device further includes a thermal bridge 15, which is disposed between the copper box 12 and the bottom wall of the conductive outer shell 11. The low-temperature support rods 13 include a first support rod group and a second support rod group. The top of the first support rod group is fixedly connected to the bottom of the copper box 12, the bottom of the first support rod group is fixedly connected to the top of the thermal bridge 15, the top of the second support rod group is fixedly connected to the bottom of the thermal bridge 15, and the bottom of the second support rod group is fixedly connected to the bottom wall of the conductive outer shell 11. The thermal bridge can be made of fiberglass G-10.

[0056] In this low-temperature constant temperature device, in order to clarify the specific structure of the cold input end 30 and the cold connection end 121, the cold input end 30 is a cold head cold conduction column, and the refrigeration device 3 is provided with a cold head mounting base 31. The cold head cold conduction column is arranged on the cold head mounting base 31. The bottom of the cold head mounting base 31 is a reference plane. The vertical distance from the top of the cold head cold conduction column to the reference plane is a first vertical distance. The vertical distance from the top of the cold head mounting base 31 to the reference plane is a second vertical distance. The first vertical distance is greater than the second vertical distance.

[0057] The cold connection end 121 is a mounting tube. When the outer wall of the cold head mounting base 31 is engaged with the mounting tube, a cold conduction cavity is formed in the mounting tube. In the cold conduction cavity, the top of the cold head cold conduction column contacts the bottom of the copper box 12.

[0058] As shown in FIG7 , in order to ensure the stability of the contact between the top of the cold head cooling column and the bottom of the copper box 12 in the cold conduction cavity, an adjustment spring 32 is introduced. On the other hand, in order to maintain the preset temperature of the cold head cooling column, a resistance wire 33 is introduced. Specifically,

[0059] A spring mounting groove is provided on the top of the cold head mounting base 31, and the adjustment spring 32 is arranged in the spring mounting groove, and the top of the adjustment spring 32 is fixedly connected to the cold head cooling column, and the bottom of the adjustment spring 32 is fixedly connected to the bottom of the spring mounting groove;

[0060] The resistance wire 33 is sleeved and disposed on the outer periphery of the cold head cooling column, and the bottom of the resistance wire 33 is in contact with the top of the cold head mounting base 31 .

[0061] In this low-temperature constant temperature device, in order to achieve precise temperature control, a temperature sensor group is introduced, which includes a first temperature sensor, a second temperature sensor, a third temperature sensor and a fourth temperature sensor. The first temperature sensor and the second temperature sensor are respectively arranged on different sides of the copper box 12, the third temperature sensor is used to be arranged on the seed crystal surface of the superconducting block 5, and the fourth temperature sensor is arranged on the cold head cooling column.

[0062] The linkage of the fourth temperature sensor and the resistance wire can further accurately ensure that the preset temperature of the cold head cooling column is maintained.

[0063] In order to facilitate real-time feedback of temperature sensing data, an aviation plug 50 is introduced. The aviation plug 50 is arranged on the conductive outer shell 11. One end of the aviation plug 50 is electrically connected to the temperature sensor group, and the other end of the aviation plug 50 is used to electrically connect to the temperature controller, and the temperature controller is used to electrically connect to the display.

[0064] In order to facilitate the inspection of the vacuum degree inside the conductive outer shell 11, a first vacuum nozzle 51 and a second vacuum nozzle 52 are introduced. The first vacuum nozzle 51 and the second vacuum nozzle 52 are both arranged on the conductive outer shell 11, and the first vacuum nozzle 51 is used to connect a vacuum gauge to check the vacuum degree inside the conductive outer shell 11, and the second vacuum nozzle 52 is used to connect a vacuum pump to achieve a preset vacuum degree.

[0065] As shown in FIG8 , the cryostat is connected to a vehicle body 71 via a connecting rod 72 , and the connecting rod 72 provides a connecting force between the vehicle body 71 and the cryostat.

[0066] Since the conductive outer shell 11 will be subjected to atmospheric pressure during operation, as shown in Figure 9, a pressure-resistant rod 8 is introduced to form a connection area at the connection position of the transverse fins 41 and the longitudinal fins 42, and a 2.5mm installation seam is set in the connection area. The pressure-resistant rod 8 is clamped in the installation seam. The outer diameter of the pressure-resistant rod 8 is 2mm, and the top of the pressure-resistant rod 8 is used to contact the inner wall surface of the top of the conductive outer shell 11. The bottom of the pressure-resistant rod 8 is fixedly connected to the top of the thermal bridge 15. The wall thickness of the top of the conductive outer shell 11 is 1.5-2mm. At this time, in this structure, on the one hand, the installation distance between the superconducting block 5 and the track set later can be reduced, thereby ensuring the flatness of the track. On the other hand, it can ensure that the conductive outer shell is subjected to stable atmospheric pressure.

[0067] Example 2:

[0068] A cryogenic constant temperature method for a superconducting magnetic levitation train, comprising:

[0069] When the refrigeration device 3 is working, the preset cooling capacity is inputted into the cooling capacity input terminal 30 and conducted through the cooling capacity connection terminal 121;

[0070] The preset cooling capacity is transferred to the superconducting bulk material accommodating cavity in the copper box 12, so that the superconducting bulk material 5 in the superconducting bulk material accommodating cavity is cooled;

[0071] According to the temperature feedback from the temperature sensor group, the power of the resistance wire is adjusted so that the superconducting block material 5 reaches a preset low temperature value.

[0072] In this method, there are two operating modes: (1) the superconducting bulk material 5 is brought to a minimum temperature of 53K to 55K and is kept at a constant temperature; (2) the superconducting bulk material 5 is set to reach a target temperature: the superconducting bulk material 5 is brought to the target temperature by adjusting the power of the resistance wire through feedback from the first temperature sensor, the second temperature sensor, the third temperature sensor and the fourth temperature sensor.

[0073] The foregoing description is merely a preferred embodiment of the present invention and is not intended to limit the present invention. Those skilled in the art will readily appreciate that various modifications and variations of the present invention are possible. Any modifications, equivalent substitutions, or improvements made within the spirit and principles of the present invention are intended to be within the scope of protection of the present invention.

[0074] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any modifications or substitutions that can be easily conceived by a person skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be based on the scope of protection of the claims.

Claims

1. A cryostat for a superconducting maglev train, characterized in that: include: A conduction device, the conduction device comprising a conduction outer shell (11), a copper box (12) and a low-temperature support rod (13), the copper box (12) being arranged in the conduction outer shell (11), the top of the low-temperature support rod (13) being fixedly connected to the bottom of the copper box (12), the bottom of the low-temperature support rod (13) being fixedly connected to the bottom wall of the conduction outer shell (11), the top of the copper box (12) being provided with a superconducting block material accommodating cavity, and the bottom of the copper box (12) being provided with a cold connection end (121); A supporting device (2), the top of the supporting device (2) is used to support the conducting device, and the bottom of the supporting device (2) is used to connect to the car body bogie bottom plate; and A refrigeration device (3), wherein the refrigeration device (3) is provided with a cold input end (30), wherein the cold input end (30) is connected to the cold connection end (121); the cold input end (30) is a cold head cold conduction column, and the refrigeration device (3) is provided with a cold head mounting base (31), wherein the cold head cold conduction column is arranged on the cold head mounting base (31), wherein the bottom of the cold head mounting base (31) is a reference plane, wherein the vertical distance from the top of the cold head cold conduction column to the reference plane is a first vertical distance, and the vertical distance from the top of the cold head mounting base (31) to the reference plane is a second vertical distance, wherein the first vertical distance is greater than the second vertical distance; The cold connection end (121) is a mounting tube. When the outer wall surface of the cold head mounting base (31) is engaged with the mounting tube, a cold conduction cavity is formed in the mounting tube. In the cold conduction cavity, the top of the cold head cold conduction column contacts the bottom of the copper box (12).

2. A cryostat for a superconducting maglev train according to claim 1, characterized in that: The invention comprises a fin device, wherein the fin device comprises a transverse fin (41) and a plurality of longitudinal fins (42). When the transverse fin (41) is arranged along the length direction of the copper box (12), and the plurality of longitudinal fins (42) are sequentially vertically connected to the transverse fin (41), a plurality of superconducting block material installation cavities (122) are formed in the superconducting block material accommodating cavity, and the volume of each superconducting block material installation cavity (122) is a preset value.

3. A cryostat for a superconducting maglev train according to claim 2, characterized in that: It comprises a plurality of superconducting blocks (5), each of the superconducting blocks (5) being connected to each of the superconducting block installation cavities (122) in a one-to-one correspondence, and the installation height of each of the superconducting blocks (5) being flush with the top of the copper box (12).

4. A cryostat for a superconducting maglev train according to claim 1, characterized in that: The conduction device also includes a thermal bridge (15), and the thermal bridge (15) is arranged between the copper box (12) and the bottom wall of the conductive outer shell (11). The low-temperature support rods (13) include a first support rod group and a second support rod group. The top of the first support rod group is fixedly connected to the bottom of the copper box (12), the bottom of the first support rod group is fixedly connected to the top of the thermal bridge (15), the top of the second support rod group is fixedly connected to the bottom of the thermal bridge (15), and the bottom of the second support rod group is fixedly connected to the bottom wall of the conductive outer shell (11).

5. A cryostat for a superconducting maglev train according to claim 1, characterized in that: It comprises an adjusting spring (32) and a resistance wire (33), the top of the cold head mounting base (31) is provided with a spring mounting groove, the adjusting spring (32) is arranged in the spring mounting groove, and the top of the adjusting spring (32) is fixedly connected to the cold head cooling column, and the bottom of the adjusting spring (32) is fixedly connected to the bottom of the spring mounting groove; The resistance wire (33) is sleeved and arranged on the outer periphery of the cold head cooling column, and the bottom of the resistance wire (33) is in contact with the top of the cold head mounting base (31).

6. A cryostat for a superconducting maglev train according to claim 5, characterized in that: The invention comprises a temperature sensor group, wherein the temperature sensor group comprises a first temperature sensor, a second temperature sensor, a third temperature sensor and a fourth temperature sensor, wherein the first temperature sensor and the second temperature sensor are respectively arranged on different sides of a copper box (12), the third temperature sensor is used to be arranged on a seed crystal surface of a superconducting block material (5), and the fourth temperature sensor is arranged on the cold head cooling column.

7. A cryostat for a superconducting maglev train according to claim 6, characterized in that: It comprises an aviation plug (50), wherein the aviation plug (50) is arranged on the conductive outer shell (11), one end of the aviation plug (50) is electrically connected to the temperature sensor group, and the other end of the aviation plug (50) is used to electrically connect to a temperature controller, and the temperature controller is used to electrically connect to a display.

8. A cryostat for a superconducting maglev train according to claim 1, characterized in that: The invention comprises a first vacuum nozzle (51) and a second vacuum nozzle (52), wherein the first vacuum nozzle (51) and the second vacuum nozzle (52) are both arranged on the conductive outer shell (11), and the first vacuum nozzle (51) is used to connect a vacuum gauge to check the vacuum degree in the conductive outer shell (11), and the second vacuum nozzle (52) is used to connect a vacuum pump.

9. A cryogenic constant temperature method for a superconducting maglev train, characterized in that: A cryostat for a superconducting maglev train according to any one of claims 1 to 8 is used, comprising: The refrigeration device (3) is in operation, a preset amount of cold is input into the cold input end (30) and is conducted through the cold connection end (121); The preset cold amount is conducted to the superconducting block material accommodating cavity in the copper box (12), so that the superconducting block material (5) in the superconducting block material accommodating cavity is cooled; According to the temperature feedback of the temperature sensor group, the power of the resistance wire is adjusted so that the superconducting block material (5) reaches a preset low temperature value.

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