A direct-cooling high-temperature superconducting magnet test platform and assembly method

Abstract

The invention discloses a direct-cooling high-temperature superconducting magnet test platform and an assembly method, comprising a refrigerator and an external dewar, wherein the refrigerator comprises a main refrigerator and a secondary refrigerator, wherein the main refrigerator and the secondary refrigerator are respectively connected to a radiation-proof cold shield and a high-temperature superconducting magnet winding through a cooling structure, wherein the high-temperature superconducting magnet winding is composed of a plurality of high-temperature superconducting coils, and the high-temperature superconducting magnet winding is connected to a power-on terminal through a high-temperature superconducting current lead. The direct-cooling high-temperature superconducting magnet test platform and the assembly method can test a plurality of large-size high-temperature superconducting coils at a time without multiple disassembly and assembly, and can also perform directional testing on the power-on coil through an active structure such as a current lead sheath quick-plug terminal, which greatly saves the time required for the magnet to reach the excitation condition to evacuate and cool down, and realizes efficient testing, and the test platform is simple in structure, reliable, easy to operate, and maneuverable to use, providing a platform for multi-coil high-temperature superconducting magnet testing.

Description

Technical Field

[0001] The invention relates to the technical field of superconducting magnet low-temperature heat transfer, in particular to a direct-cooling high-temperature superconducting magnet test platform and an assembly method. Background Art

[0002] The stable operation of superconducting magnets is determined by multiple factors, one of the key factors being the low-temperature environment. From the perspective of how the low-temperature environment is obtained, it can be divided into two methods: liquid helium immersion cooling and direct cooling by refrigerators. However, due to the shortage and high cost of helium resources, direct cooling of magnets by refrigerators is becoming more and more popular in the market.

[0003] For high-temperature superconducting magnets, the superconducting state can be achieved only in the liquid nitrogen temperature zone. A single-stage GM refrigerator with a large cooling capacity can be used for cooling to provide a superconducting environment. However, the general high-temperature superconducting magnet coil test platform cannot realize multiple coil sequencing tests or simultaneous tests. Only after a single coil test is completed, another coil can be tested. Each test process requires evacuation, cooling, and reheating. The test process is cumbersome, the test time cycle is long, and the test efficiency is low.

[0004] A superconducting magnet and a composite magnetic refrigerator are disclosed in the Chinese invention patent application publication specification CN 202010692707.9U. Although combining a regenerative refrigerator with a magnetic refrigerator is an effective means to obtain a lower temperature, a method of adding a remaining cold head to the end regenerator of the regenerative refrigerator is adopted, so that one or more cold heads are added to the end, and different cold heads provide different cooling capacity, and other components except the refrigerant salt are cooled to a suitable temperature, so that the coldest end cold head serves as the ambient temperature of the magnetic refrigerator, and other required cooling capacity is provided by the remaining cold heads with higher temperatures. However, it is impossible to implement multiple coil sequencing tests or simultaneous tests. Only after a single coil test is completed, another coil can be tested. At the same time, it is not perfect in terms of its directional testing.

[0005] To this end, the present invention has developed a direct-cooling high-temperature superconducting magnet testing platform and an assembly method. Summary of the invention

[0006] 1. Technical issues to be resolved

[0007] In view of the shortcomings of the prior art that it is impossible to implement sequencing testing or simultaneous testing of multiple coils, and the testing process requires the processes of evacuation, cooling, and reheating, the testing process is cumbersome, the testing time period is long, and the testing efficiency is low, the present invention provides a direct-cooling high-temperature superconducting magnet testing platform and an assembly method, which have the advantages of being able to test multiple high-temperature superconducting coils at a time without multiple disassembly and assembly, and being able to perform directional testing on energized coils, thereby solving the problems raised in the prior art.

[0008] (II) Technical solution

[0009] To achieve the above-mentioned purpose, the present invention provides the following technical solutions: a direct-cooling high-temperature superconducting magnet test platform, comprising a refrigerator and an external dewar, the refrigerator comprising a main refrigerator and a secondary refrigerator, the main refrigerator and the secondary refrigerator are respectively connected to a radiation-proof cold shield and a high-temperature superconducting magnet winding through a cooling structure, and the high-temperature superconducting magnet winding is composed of a plurality of high-temperature superconducting coils.

[0010] Preferably, a motor magnetic shielding assembly is provided on the outer surface of the refrigerator.

[0011] Preferably, a support frame is provided outside the high-temperature superconducting magnet winding, and the support frame and the outer dewar are made of insulating materials.

[0012] Preferably, an evacuation valve, a vacuum gauge and a signal terminal are respectively provided at the bottom of the outer Dewar.

[0013] Preferably, the high-temperature superconducting magnet winding is connected to a power-on terminal through a high-temperature superconducting current lead, and the power-on terminal includes a quick-plug terminal, which is composed of a retaining spring structure, a bellows movable base, a limiter and a power-on terminal, and the power-on terminal is connected to a wiring row.

[0014] Preferably, the outer surface of the outer dewar is fixedly connected with a lifting structure.

[0015] Preferably, the secondary refrigerator is a 70K-class single-stage GM refrigerator, and the primary refrigerator is a 20K-class single-stage GM refrigerator, and the number of the primary refrigerator is two.

[0016] Preferably, a movable bracket is fixedly connected to the bottom of the outer dewar.

[0017] The present invention also proposes a direct-cooling high-temperature superconducting magnet assembly method, comprising the following steps:

[0018] a. External Dewar support base plate installation:

[0019] First, the outer Dewar bottom plate is supported by a mobile bracket to form a certain bottom working space, and three GM refrigerator cold heads, power terminals, signal terminals, evacuation valves and vacuum gauges are installed on the outer Dewar bottom plate;

[0020] b. Support frame installation:

[0021] First, a support frame structure is installed on the bottom plate of the outer dewar. A ring is provided in the middle of the support frame as a reinforcement structure, and the radiation-proof cold shield bottom plate is hung on the support frame through a connecting structure.

[0022] Then, the radiation-proof cold shield bottom plate is connected to the 70K-class single-stage GM refrigerator through a cooling structure to achieve heat conduction;

[0023] c. Hoisting and installation of high temperature superconducting magnet windings:

[0024] Use the hoisting structure to hoist the assembled high-temperature superconducting magnet winding onto the support frame as a whole;

[0025] Then, the refrigerator is connected to the high-temperature superconducting magnet winding by using the high-temperature superconducting magnet cooling structure, and then the high-temperature superconducting magnet winding is connected to the power-on interface of the room-temperature end part by using the high-temperature superconducting current lead;

[0026] d. Anti-radiation cold screen installation:

[0027] Fix the cold shield cylinder and the upper top plate to the installed and fixed cold shield bottom plate through the lifting holes, and fix them with screws, and then arrange multiple layers of thermal radiation shielding layers around the cold shield cylinder;

[0028] e. Dewar cylinder installation:

[0029] The outer Dewar cylinder and top plate are hoisted and placed on the outer Dewar bottom plate, and then the sealing ring at the sealing position is compressed by the vacuum sealing quick-release caliper.

[0030] f. Direct cooling high temperature superconducting magnet test platform evacuation:

[0031] Use the vacuum valve to connect to the external vacuum pump group, and use the vacuum pump group to evacuate the inside of the magnet to below 10-3Pa;

[0032] g. High temperature superconducting magnet cooling:

[0033] Turn on the 70K single-stage GM refrigerator and the 20K single-stage GM refrigerator to cool down the machine. Use the signal from the signal terminal to detect the overall temperature of the high-temperature superconducting magnet until the temperature drops to the target value.

[0034] h. After the preparations are completed, the high temperature superconducting magnet is powered on and excited;

[0035] According to the test plan, the coil inside the test platform is tested in a maneuverable manner.

[0036] Preferably, during testing, the high temperature superconducting magnet winding is connected to an external excitation power supply via an energized terminal.

[0037] (III) Beneficial effects

[0038] Compared with the prior art, the present invention provides a direct-cooling high-temperature superconducting magnet test platform and assembly method, which has the following beneficial effects:

[0039] 1. The direct-cooling high-temperature superconducting magnet test platform and assembly method can test multiple large-size high-temperature superconducting coils at one time without multiple disassembly and assembly. In addition, the test platform has a simple and reliable structure, is easy to operate, and is mobile in use, providing a platform for multi-coil high-temperature superconducting magnet testing.

[0040] 2. The direct-cooling high-temperature superconducting magnet test platform and assembly method couple the high-temperature superconducting magnet windings through a single-stage Stirling refrigerator with large cooling capacity. Since the direct system has sufficient cooling capacity, it can balance the heat generated by the large current flowing through the terminal of multiple coil windings, and at the same time, it can achieve rapid cooling of large-size, heavy-weight, and high-heat-capacity high-temperature superconducting magnet windings.

[0041] 3. The direct-cooling high-temperature superconducting magnet test platform and assembly method can realize the rapid power-on and power-off of the internal coil of the high-temperature superconducting magnet winding through the power-on terminal, and can selectively conduct power-on testing on the target coil. At the same time, the test process is flexible and efficient, thereby making the maximum reasonable use of the cooling capacity of the entire direct cooling system.

[0042] 4. The direct-cooling high-temperature superconducting magnet test platform and assembly method are convenient for installing and disassembling the direct cooling system of the refrigerator and the high-temperature superconducting magnet winding, and are easy to replace, thereby improving the test efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] Figure 1 A three-dimensional structural schematic diagram of a direct-cooling high-temperature superconducting magnet test platform and an assembly method proposed by the present invention;

[0044] Figure 2 A schematic diagram of the internal structure of the outer and inner Dewar in a direct-cooling high-temperature superconducting magnet test platform and assembly method proposed by the present invention;

[0045] Figure 3 A schematic diagram of the three-dimensional structure of the power-on terminals in a direct-cooling high-temperature superconducting magnet test platform and assembly method proposed by the present invention;

[0046] Figure 4 The present invention provides a schematic diagram of the side view structure of the power-on terminals in a direct-cooling high-temperature superconducting magnet test platform and assembly method.

[0047] In the figure: 1. Refrigerator; 101. Main refrigerator; 102. Secondary refrigerator; 2. Mobile bracket; 3. Motor magnetic shielding assembly; 4. Evacuation valve; 5. Vacuum gauge; 6. Wiring row; 7. Power terminal; 8. Signal terminal; 9. Vacuum sealing quick release caliper; 10. External dewar; 11. Lifting structure; 12. Radiation-proof cold shield; 13. High-temperature superconducting current lead; 14. Cooling structure; 15. High-temperature superconducting magnet winding; 16. Support frame; 17. Quick-plug terminal; 18. Bellows movable base; 19. Limiter; 20. Power terminal. DETAILED DESCRIPTION

[0048] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0049] See also Figure 1-4 A direct-cooling high-temperature superconducting magnet test platform includes a refrigerator 1 and an external dewar 10. The refrigerator 1 includes a main refrigerator 101 and a secondary refrigerator 102. The main refrigerator 101 and the secondary refrigerator 102 are respectively connected to a radiation-proof cold shield 12 and a high-temperature superconducting magnet winding 15 through a cooling structure 14. The high-temperature superconducting magnet winding 15 is composed of a plurality of high-temperature superconducting coils.

[0050] Preferably, a motor magnetic shielding assembly 3 is provided on the outer surface of the refrigerator 1 .

[0051] Preferably, a support frame 16 is provided on the outside of the high-temperature superconducting magnet winding 15. The support frame 16 and the outer dewar 10 are made of insulating materials and serve as the main load-bearing structure for suspending and hoisting the high-temperature superconducting magnet winding 15. While ensuring the supporting strength, it can effectively reduce the heat leakage between the low-temperature component and the room temperature, thereby reducing the heat load of the refrigerator, and further ensuring the cooling of the high-temperature superconducting magnet winding 15.

[0052] Preferably, the bottom of the outer dewar 10 is respectively provided with an evacuation valve 4, a vacuum gauge 5 and a signal terminal 8, and the signal terminal 8 is used to detect the power-on signal.

[0053] Preferably, the high-temperature superconducting magnet winding 15 is connected to a power terminal 7 through a high-temperature superconducting current lead 13, and the power terminal 7 includes a quick-plug terminal 17, and the quick-plug terminal 17 is composed of a spring structure, a bellows movable base 18, a limiter 19 and a power terminal 20, and the power terminal 7 is connected to the wiring row 6;

[0054] The power-on terminal 7 uses the quick-plug terminal 17 to realize the rapid power-on and power-off of the internal coil of the high-temperature superconducting magnet winding, connects and powers the target power-on coil, and disconnects the power-on part of the coil that is not temporarily powered on and excites the test, thereby reducing the heat conduction leakage from the room temperature end to the magnet coil;

[0055] This flexible on-off mode can reasonably and fully utilize the cooling capacity of the GM refrigerator, thereby greatly reducing the cooling time of the high-temperature superconducting magnet and improving the test efficiency.

[0056] The high temperature superconducting current lead 13 serves as a current passage for the high temperature superconducting magnet winding 15. With its good high temperature superconducting property, the Joule heat after power-on is greatly reduced, thereby greatly reducing the heat load of the GM refrigerator.

[0057] Preferably, a lifting structure 11 is fixedly connected to the outer surface of the outer dewar 10 .

[0058] Preferably, the secondary refrigerator 102 is preferably a 70K-class single-stage GM refrigerator, and the main refrigerator 101 is preferably a 20K-class single-stage GM refrigerator, and the number is two.

[0059] Preferably, the bottom of the outer dewar 10 is fixedly connected with a movable bracket 2.

[0060] The present invention also proposes a direct-cooling high-temperature superconducting magnet assembly method, comprising the following steps:

[0061] a. Installation of the outer Dewar 10 support base plate:

[0062] First, the bottom plate of the outer Dewar 10 is supported by the mobile bracket 2 to form a certain bottom working space, and three GM refrigerator cold heads, power terminals 7, signal terminals 8, evacuation valves 4 and vacuum gauges 5 are installed on the bottom plate of the outer Dewar 10;

[0063] b. Installation of support frame 16:

[0064] First, a support frame 16 structure is installed on the bottom plate of the outer dewar 10. A ring is provided in the middle of the support frame 16 as a reinforcement structure, and the bottom plate of the radiation-proof cold shield 12 is suspended on the support frame 16 through a connecting structure;

[0065] Then, the bottom plate of the radiation-proof cold shield 12 is connected to the 70K-class single-stage GM refrigerator by heat conduction through the cooling structure 14, so that the cold energy of the 70K-class single-stage GM refrigerator is transported to the cold shield cylinder and the cold shield top plate;

[0066] The support frame 16 is the main load-bearing structure, serving as the load-bearing support for all structures including the interior of the outer dewar 10, the radiation-proof cold shield 12, the high-temperature superconducting magnet assembly 15, and the hoisting structure.

[0067] c. Hoisting and installation of high temperature superconducting magnet winding 15:

[0068] Use the hoisting structure 11 to hoist the assembled high-temperature superconducting magnet winding 15 onto the support frame 16 as a whole;

[0069] Then, the refrigerator 1 is connected to the high-temperature superconducting magnet winding 15 by using the cooling structure 14, and then the high-temperature superconducting magnet winding 15 is connected to the power-on interface of the room-temperature end part by using the high-temperature superconducting current lead 13;

[0070] d. Installation of radiation-proof cold shield 12:

[0071] Fix the radiation-proof cold shield 12 cylinder and the upper top plate to the installed and fixed radiation-proof cold shield 12 bottom plate through the lifting holes, and fix them with screws at the same time, so that the cold energy of the refrigerator conducted to the radiation-proof cold shield 12 bottom plate is further transferred to the radiation-proof cold shield 12 cylinder and the bottom plate, and then arrange multiple layers of thermal radiation shielding layers around the cold shield cylinder to isolate the radiation heat of the external Dewar 10;

[0072] e. Installation of outer Dewar 10 cylinder:

[0073] By hoisting, the outer Dewar 10 cylinder and its top plate are hoisted and placed on the bottom plate of the outer Dewar 10, and then the sealing ring at the sealing position is compressed by the vacuum sealing quick-release caliper 9 to achieve overall vacuum sealing.

[0074] f. Direct cooling high temperature superconducting magnet test platform evacuation:

[0075] Use the vacuum valve 4 to connect to the external vacuum pump group, and use the vacuum pump group to evacuate the inside of the magnet to below 10-3Pa;

[0076] g. Cooling of high temperature superconducting magnet winding 15:

[0077] The main refrigerator 101 and the secondary refrigerator 102 are turned on to perform cooling and the overall temperature of the high-temperature superconducting magnet winding 15 is detected through the signal derived from the signal terminal 8 until the temperature drops to the target value.

[0078] h. After the preparations are completed, the high temperature superconducting magnet is powered on and excited;

[0079] According to the test plan, the coil inside the test platform is tested in a maneuverable manner.

[0080] Preferably, during testing, the high temperature superconducting magnet winding 15 is connected to an external excitation power source via the power-on terminal 20 .

[0081] The top plate of the outer Dewar 10 is provided with an evacuation interface, temperature, voltage and other signal interfaces for detecting signals.

[0082] The refrigerator 1 can provide a large amount of cooling capacity in the liquid nitrogen temperature zone to realize the excitation test of the high-temperature superconducting magnet winding 15 with large current, large size and multi-coil direct cooling. The size and weight of the entire high-temperature superconducting coil winding 15 are large, and the external dimensions of the test platform are large. At the same time, the three single-stage refrigerators have sufficient cooling capacity and can perform large current tests on the high-temperature superconducting coils. The large Joule heat at the joint position can be balanced by the large cooling capacity of the single-stage refrigerator.

[0083] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the terms "include", "comprise" or any other variants thereof are intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the statement "comprise one" do not exclude the existence of other identical elements in the process, method, article or device including the elements.

Claims

1. A direct-cooling high-temperature superconducting magnet test platform, comprising a refrigerator and an external dewar, Features: The refrigerator comprises a main refrigerator and a secondary refrigerator, wherein the main refrigerator and the secondary refrigerator are respectively connected to a radiation-proof cold shield and a high-temperature superconducting magnet winding through a cooling structure, wherein the high-temperature superconducting magnet winding is composed of a plurality of high-temperature superconducting coils; The high-temperature superconducting magnet winding is connected to a power-on terminal through a high-temperature superconducting current lead. The power-on terminal includes a quick-plug terminal. The quick-plug terminal is composed of a spring structure, a bellows movable base, a limiter and a power-on terminal. The power-on terminal is connected to a wiring row. The power-on terminal uses the quick-plug terminal to realize rapid power-on and power-off of the internal coil of the high-temperature superconducting magnet winding. The target power-on coil is connected and powered on. For the coil that is not temporarily powered on and off for excitation testing, the power-on part is disconnected to reduce heat conduction leakage from the room temperature end to the magnet coil.

2. A direct-cooling high-temperature superconducting magnet testing platform according to claim 1, Features: The outer surface of the refrigerator is provided with a motor magnetic shielding component.

3. A direct-cooling high-temperature superconducting magnet testing platform according to claim 1, Features: A support frame is arranged outside the high-temperature superconducting magnet winding, and the support frame and the outer dewar are made of insulating materials.

4. A direct-cooling high-temperature superconducting magnet testing platform according to claim 1, Features: The bottom of the outer Dewar is respectively provided with an evacuation valve, a vacuum gauge and a signal terminal.

5. A direct-cooling high-temperature superconducting magnet testing platform according to claim 1, Features: The outer surface of the outer dewar is fixedly connected with a hoisting structure.

6. A direct-cooling high-temperature superconducting magnet testing platform according to claim 1, Features: The secondary refrigerator is preferably a 70K-class single-stage GM refrigerator, and the primary refrigerator is preferably a 20K-class single-stage GM refrigerator, and the number of the primary refrigerator is two.

7. A direct-cooling high-temperature superconducting magnet testing platform according to claim 1, Features: The bottom of the outer dewar is fixedly connected with a movable bracket.

8. A method for assembling a direct-cooled high-temperature superconducting magnet, the method being applied to the direct-cooled high-temperature superconducting magnet test platform according to any one of claims 1 to 7, It is characterized in that The following steps are involved: a. External Dewar support base plate installation: First, the outer Dewar bottom plate is supported by a mobile bracket to form a certain bottom working space, and three GM refrigerator cold heads, power terminals, signal terminals, evacuation valves and vacuum gauges are installed on the outer Dewar bottom plate; b. Support frame installation: First, a support frame structure is installed on the bottom plate of the outer dewar. A ring is provided in the middle of the support frame as a reinforcement structure, and the radiation-proof cold shield bottom plate is hung on the support frame through a connecting structure. Then, the radiation-proof cold shield bottom plate is connected to the 70K-class single-stage GM refrigerator through a cooling structure to achieve heat conduction; c. Hoisting and installation of high temperature superconducting magnet windings: Use the hoisting structure to hoist the assembled high-temperature superconducting magnet winding onto the support frame as a whole; Then, the refrigerator is connected to the high-temperature superconducting magnet winding by using the high-temperature superconducting magnet cooling structure, and then the high-temperature superconducting magnet winding is connected to the power-on interface of the room-temperature end part by using the high-temperature superconducting current lead; d. Anti-radiation cold screen installation: Fix the cold shield cylinder and the upper top plate to the installed and fixed cold shield bottom plate through the lifting holes, and fix them with screws, and then arrange multiple layers of thermal radiation shielding layers around the cold shield cylinder; e. External Dewar Cylinder Installation: By hoisting, the outer Dewar cylinder and top plate are hoisted and placed on the outer Dewar bottom plate, and then the sealing ring at the sealing position is compressed by the vacuum sealing quick release caliper; f. Direct cooling high temperature superconducting magnet test platform evacuation: Use the vacuum valve to connect to the external vacuum pump set, and use the vacuum pump set to evacuate the inside of the magnet to 10 -3 Below Pa; g. High temperature superconducting magnet cooling: Turn on the 70K single-stage GM refrigerator and the 20K single-stage GM refrigerator to cool down the temperature. Use the signal from the signal terminal to detect the overall temperature of the high-temperature superconducting magnet until the temperature drops to the target value. h. After the preparations are completed, the high temperature superconducting magnet is powered on and excited; According to the test plan, the coil inside the test platform is tested in a maneuverable manner.

9. A method for assembling a direct-cooled high-temperature superconducting magnet according to claim 8, Features: During testing, the high-temperature superconducting magnet windings are connected to an external excitation power supply through energized terminals.

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