A conduction-cooled superconducting magnet

Abstract

The application discloses a conduction cooling superconducting magnet, and relates to the technical field of superconductivity, which comprises a refrigerator cold head, a second-stage cold head for providing superconducting working temperature cold energy, a superconducting coil and a superconducting joint, a first heat transfer connecting piece for connecting the second-stage cold head of the refrigerator cold head with the superconducting coil and the superconducting joint, a switch container, a superconducting switch sealed in the switch container, a gas medium filled in the switch container and wrapping the superconducting switch, and a second heat transfer connecting piece for connecting the switch container with the second-stage cold head of the refrigerator cold head, wherein the second heat transfer connecting piece and the first heat transfer connecting piece converge at the second-stage cold head of the refrigerator cold head, and heat generated by the superconducting switch is sequentially transferred to the second-stage cold head of the refrigerator cold head through the gas medium, the switch container and the second heat transfer connecting piece. The conduction cooling superconducting magnet has the advantages that when the superconducting switch is opened, the thermal interference of the superconducting switch on the superconducting coil and the superconducting joint is obviously weakened, and the operation reliability is improved.

Description

Technical Field

[0001] This invention relates to the field of superconducting technology, and in particular to a conductive cooling superconducting magnet. Background Technology

[0002] Superconducting magnets require extremely low temperatures (around -269°C) to achieve superconductivity. Conductive cooling superconducting magnets directly conduct heat through the cold head of a cryostat (usually a GM cryostat or pulse tube cryostat) to cool components such as superconducting coils, superconducting connectors, and superconducting switches. This method has the advantages of compact structure and no need for liquid refrigerant, and is currently an important development direction for superconducting magnet technology.

[0003] In a conductive cooling superconducting magnet system, the superconducting switch is a key component for achieving closed-loop operation. The working principle of the superconducting switch is as follows: during excitation (i.e., magnetizing the superconducting coil) or demagnetization, the superconducting switch needs to be heated to transition from a superconducting state (a state with zero resistance) to a normal state (a state with resistance). This process is called "opening" the superconducting switch. After excitation or demagnetization is completed, heating stops, and the superconducting switch cools down and re-enters the superconducting state. This process is called "closing" the superconducting switch, thus forming a closed-loop circuit and enabling the superconducting magnet to enter a continuous operating mode.

[0004] However, existing conductive cooling superconducting magnets present a thorny technical problem. In conventional designs, the cooling channels for superconducting switches, superconducting connectors, and superconducting coils are ultimately connected to the connecting block at the lower end of the second stage of the cryogenic cold head. In other words, these superconducting components are directly thermally connected via a high thermal conductivity metal material (such as oxygen-free copper), and their cooling circuits are directly interconnected.

[0005] In this structure, when the superconducting switch needs to be heated to open during excitation, the superconducting switch itself becomes a heat source. Since the superconducting switch is directly connected to the cooling circuits of the superconducting coil and the superconducting connector, the heat generated by the superconducting switch is directly conducted to the superconducting connector and the superconducting coil through the connecting block, causing the temperature of these components to rise. If the excitation time is long, the heater needs to operate continuously, and the generation and accumulation of heat will seriously affect the thermal stability of the superconducting magnet. In severe cases, it can cause the superconducting coil to lose its superconductivity, making normal excitation impossible. Excitation must be stopped and the system must be allowed to cool down before restarting, resulting in intermittent excitation operation, severely impacting actual efficiency and magnet reliability.

[0006] If the heating power is reduced to minimize the heat impact, there is a risk that the superconducting switch may not be able to open completely (i.e., the heating amount is insufficient to bring the superconducting switch back to its normal state). Therefore, how to minimize the thermal impact of the superconducting switch's heat on components such as the superconducting coil and superconducting connector while ensuring that the superconducting switch can be reliably opened, and at the same time not affecting the rapid cooling and closing of the superconducting switch after excitation, has become a long-standing technical problem that needs to be solved by those skilled in the art. Summary of the Invention

[0007] The purpose of this invention is to provide a conductive cooling superconducting magnet that solves the technical problems existing in current conductive cooling superconducting magnets.

[0008] To achieve the above objectives, the present invention provides a conductive cooling superconducting magnet, comprising:

[0009] The refrigerator cold head has a second-stage cold head for providing cooling capacity at the superconducting operating temperature;

[0010] Superconducting coils and superconducting connectors;

[0011] The first heat transfer connector connects the second stage cold head of the refrigerator cold head to the superconducting coil and the superconducting connector.

[0012] Switch container;

[0013] A superconducting switch, sealed inside the switch container;

[0014] A gaseous medium is filled inside the switch container to encapsulate the superconducting switch.

[0015] The second heat transfer connector connects the switching container to the second stage cold head of the refrigerator cold head, and the second heat transfer connector and the first heat transfer connector merge at the second stage cold head of the refrigerator cold head;

[0016] The heat generated by the superconducting switch is sequentially transferred to the second-stage cold head of the refrigerator cold head via the gas medium, the switch container, and the second heat transfer connector.

[0017] In some technical solutions, the second heat transfer connector includes a connecting block and a heat transfer connector; the connecting block is made of a high thermal conductivity material and is fixedly connected to the switching container; one end of the heat transfer connector is connected to the connecting block, and the other end is connected to the second-stage cold head of the refrigerator cold head.

[0018] In some technical solutions, the second heat transfer connector includes a heat transfer connector, one end of which is connected to the switching container, and the other end is connected to the second-stage cold head of the refrigerator cold head.

[0019] In some technical solutions, the switch container is provided with a sealed electrical connection structure, which includes a stainless steel shell welded to the switch container and an insulating sealant filled inside the stainless steel shell, and the current lead of the superconducting switch passes through the insulating sealant.

[0020] In some technical solutions, a first temperature probe, a second temperature probe, and a third temperature probe are also included; the first temperature probe is disposed on the sealed electrical connection structure of the switch container; the second temperature probe is disposed on the bottom of the switch container; and the third temperature probe is disposed on the outer surface of the superconducting switch.

[0021] In some technical solutions, the switch container is provided with a sealing element, the sealing element comprising:

[0022] The housing has an internal cavity, and one end of the housing is connected to the interior of the switch container;

[0023] The sealing core is movably disposed in the cavity inside the housing;

[0024] A sealing flange is located at the end of the housing opposite to the switch container;

[0025] The outer sealing plate is detachably fixed to the sealing flange;

[0026] A sealing ring is disposed between the sealing flange and the outer sealing plate.

[0027] In some technical solutions, a cryogenic container and a cold shield are also included. The cryogenic container is wrapped around the outside of the cold shield, which is wrapped around the outside of the switch container, the superconducting coil, and the superconducting connector, and is thermally connected to the first-stage cold head of the refrigerator cold head to absorb heat radiated from the room temperature environment to the cryogenic region.

[0028] In some technical solutions, the sealing element is located inside the cold shield.

[0029] In some technical solutions, the end of the sealing member away from the switch container extends through the cold shield and the cryogenic container to the outside of the cryogenic container.

[0030] In some technical solutions, the gas medium is helium, and the filling pressure of the gas medium in the switch container at room temperature is 1 standard atmosphere.

[0031] Compared to the aforementioned background technology, the conductive cooling superconducting magnet provided by this invention has a superconducting switch sealed in a switch container filled with a gaseous medium. The cooling method of the superconducting switch is changed from the traditional direct solid-state heat conduction to a heat transfer method that first absorbs and convects through the gaseous medium and then conducts heat through the solid. This significantly reduces the heat transferred to the superconducting coil and the superconducting connector. When the superconducting switch is turned on, the thermal interference to the superconducting coil and the superconducting connector is significantly reduced, avoiding excitation interruption caused by excessively high superconducting coil temperature, and improving the stability and reliability of the superconducting magnet. Attached Figure Description

[0032] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the provided drawings without creative effort.

[0033] Figure 1 This is a schematic diagram of the structure of the conductive cooling superconducting magnet provided in an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of the sealing component provided in an embodiment of the present invention;

[0035] Figure 3 This is a schematic diagram of the structure of the second heat transfer connector provided in some embodiments of the present invention;

[0036] Figure 4 A schematic diagram of the closed-loop operation of the superconducting magnet for conductive cooling;

[0037] Figure 5 This is a schematic diagram of a sealing element provided in some embodiments of the present invention.

[0038] Figures 1 to 5Chinese reference numerals: 1. Cold head of the refrigerator; 101. First-stage cold head; 102. Second-stage cold head; 103. Conductive block; 2. Superconducting coil; 201. Superconducting connector; 3. First heat transfer connection; 4. Switching container; 5. Superconducting switch; 6. Gas medium; 7. Second heat transfer connection; 701. Connecting block; 702. Heat transfer connection; 8. Sealed electrical connection structure; 9. First temperature probe; 10. Second temperature probe; 11. Third temperature probe 12. Head; 12. Sealing component; 1201. Shell; 1202. Sealing core; 1203. Sealing flange; 1204. Outer sealing plate; 1205. Sealing ring; 13. Cryogenic container; 14. Cold shield; 15. First tie rod; 16. Second tie rod; 17. Lead wire one; 18. Lead wire two; 19. Lead wire three; 20. Lead wire four; 21. Lead wire five; 22. Lead wire six; 23. Lead wire seven; 24. Lead wire eight; 25. Lead wire nine; 26. Lead wire ten. Detailed Implementation

[0039] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0040] To enable those skilled in the art to better understand the present invention, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0041] Please refer to this as well. Figures 1 to 5 The present invention provides a conductive cooling superconducting magnet that can significantly reduce the heat transferred to the superconducting coil 2 and the superconducting connector 201. When the superconducting switch 5 is turned on, the thermal interference to the superconducting coil 2 and the superconducting connector 201 is significantly reduced, thereby improving the operational reliability of the superconducting magnet.

[0042] The conductive cooling superconducting magnet provided by this invention includes:

[0043] The refrigerator cold head 1 has a second-stage cold head 102 for providing cooling capacity at the superconducting operating temperature;

[0044] Superconducting coil 2 and superconducting connector 201;

[0045] The first heat transfer connector 3 connects the second stage cold head 102 of the refrigerator cold head 1 with the superconducting coil 2 and the superconducting connector 201.

[0046] Switch container 4;

[0047] The superconducting switch 5 is sealed inside the switch container 4;

[0048] Gas medium 6 is filled inside the switch container 4 and encapsulates the superconducting switch 5;

[0049] The second heat transfer connector 7 connects the switch container 4 to the second stage cold head 102 of the refrigerator cold head 1, and the second heat transfer connector 7 and the first heat transfer connector 3 meet at the second stage cold head 102 of the refrigerator cold head 1.

[0050] The heat generated by the superconducting switch 5 is sequentially transferred to the second-stage cold head 102 of the refrigerator cold head 1 via the gas medium 6, the switch container 4, and the second heat transfer connector 7.

[0051] Specifically, the conductive cooling superconducting magnet includes a refrigerator cold head 1, a superconducting coil 2, a superconducting connector 201, a first heat transfer connector 3, a switching container 4, a superconducting switch 5, a gas medium 6, and a second heat transfer connector 7.

[0052] The cryogenic cold head 1 has a two-stage structure. The second-stage cold head 102 provides the cooling required for the superconducting operating temperature, which is typically in the 4 K temperature range, approximately 4 Kelvin (about -269 degrees Celsius). The first-stage cold head 101 provides cooling in the approximately 50 K temperature range, primarily for cooling the cold shield 14. The superconducting coil 2 and the superconducting connector 201 are the core components of the superconducting magnet and can be made of low-temperature superconducting materials such as niobium-titanium alloy. They require operation in the 4 K temperature range to achieve a superconducting state.

[0053] The first heat transfer connector 3 connects the second-stage cold head 102 of the refrigerator cold head 1 to the superconducting coil 2 and the superconducting connector 201. Specifically, a conductive block 103 is fixed to the end of the second-stage cold head 102. This conductive block 103 is made of a high thermal conductivity material such as oxygen-free copper. The first heat transfer connector 3 can be a copper braided strip or a copper busbar, with one end connected to the conductive block 103 and the other end connected to the superconducting coil 2 and the superconducting connector 201, respectively, to conduct the cooling energy generated by the second-stage cold head 102 to the superconducting coil 2 and the superconducting connector 201.

[0054] The switch container 4 is a sealed container, typically made of stainless steel, which provides excellent low-temperature performance and sealing. The superconducting switch 5 is sealed inside the switch container 4. The switch container 4 is filled with a gaseous medium 6, which encloses the superconducting switch 5. The gaseous medium 6 is preferably helium because helium does not condense at 4K and has extremely high specific heat capacity (cold storage capacity).

[0055] The second heat transfer connector 7 connects the switch container 4 to the second-stage cold head 102 of the refrigerator cold head 1, and the second heat transfer connector 7 and the first heat transfer connector 3 converge at the second-stage cold head 102 of the refrigerator cold head 1. Specifically, one end of the second heat transfer connector 7 is fixedly connected to the switch container 4, and the other end is connected to the conductive block 103 on the second-stage cold head 102.

[0056] During operation, the heat generated by the superconducting switch 5 is sequentially transferred to the second-stage cold head 102 of the refrigerator cold head 1 via the gas medium 6, the switch container 4, and the second heat transfer connector 7. Because the gas medium 6 has an extremely high specific heat capacity in the 4K temperature range, it can effectively absorb the heat generated by the superconducting switch 5 and suppress rapid temperature rise. Therefore, only a small portion of the heat is transferred to the conductive block 103, significantly reducing the thermal impact on the superconducting coil 2 and the superconducting connector 201. Simultaneously, when excitation ends and heating ceases, the cooling energy of the second-stage cold head 102 is rapidly conducted to the superconducting switch 5 via the opposite path, causing it to cool quickly and return to its superconducting state.

[0057] With this configuration, the cooling method of the superconducting switch 5 changes from the traditional direct solid-state heat conduction to an indirect heat transfer method that combines absorption and convection through the gas medium 6 followed by solid-state heat conduction. Utilizing the excellent cold storage performance of the gas medium 6 at a low temperature of 4K, the specific heat capacity of the same mass of gas medium 6 is thousands of times that of the same mass of metallic and non-metallic solids, thus effectively absorbing heat and suppressing rapid temperature rise. After being buffered by the gas medium 6, the remaining heat is then transferred to the second-stage cold head 102 via the switch container 4 and the second heat transfer connector 7. This heat transfer method significantly reduces the heat transferred to the superconducting coil 2 and the superconducting connector 201, thereby improving the thermal stability during the excitation process of the superconducting magnet and effectively solving the thermal interference problem of the superconducting switch 5's heat generation on the superconducting coil 2 and the superconducting connector 201 in conventional structures.

[0058] In some embodiments, the second heat transfer connector 7 includes a connecting block 701 and a heat transfer connector 702; the connecting block 701 is made of a high thermal conductivity material and is fixedly connected to the switch container 4; one end of the heat transfer connector 702 is connected to the connecting block 701, and the other end is connected to the second stage cold head 102 of the refrigerator cold head 1.

[0059] Please refer to this as well. Figures 3 to 5 The second heat transfer connector 7 includes a connecting block 701 and a heat transfer connector 702. The connecting block 701 is made of a high thermal conductivity material, preferably oxygen-free copper. The connecting block 701 is fixedly connected to the switch container 4, specifically by welding, to form a single unit with the switch container 4. One end of the heat transfer connector 702 is connected to the connecting block 701, and the other end is connected to the conductive block 103 on the second-stage cold head 102 of the refrigerator cold head 1. The heat transfer connector 702 can be made of copper braided strip or copper busbar, and its material is also a high thermal conductivity material such as oxygen-free copper.

[0060] With this configuration, the heat from the side wall of the switch container 4 can be effectively collected and conducted outward through the connecting block 701 as an intermediate transition component; the heat transfer connector 702 provides a heat conduction path from the switch container 4 to the second-stage cold head 102, which is convenient to adapt to the spatial layout inside the magnet.

[0061] During operation, the heat generated by the superconducting switch 5 is transferred to the connecting block 701 via the gas medium 6 and the side wall of the switch container 4, and then to the second-stage cold head 102 via the heat transfer connector 702. After heating stops, the cooling energy is transferred along the opposite path, causing the superconducting switch 5 to cool down rapidly.

[0062] In some embodiments, the second heat transfer connector 7 includes a heat transfer connector 702, one end of which is connected to the switch container 4, and the other end is connected to the second stage cold head 102 of the refrigerator cold head 1.

[0063] Please refer to Figure 1 In this embodiment, the second heat transfer connector 7 only includes the heat transfer connector 702, eliminating the connecting block 701. One end of the heat transfer connector 702 is directly connected to the side wall of the switching container 4, and the other end is connected to the conductive block 103 of the second-stage cold head 102 of the refrigerator cold head 1. The heat transfer connector 702 achieves the thermal connection between the second-stage cold head 102 of the refrigerator cold head 1 and the switching container 4.

[0064] This design reduces the complexity of processing and assembly, and improves the reliability and heat transfer efficiency of the structure.

[0065] In some embodiments, the switch container 4 is provided with a sealed electrical connection structure 8, which includes a stainless steel shell welded to the switch container 4 and an insulating sealant filled inside the stainless steel shell, through which the current lead of the superconducting switch 5 passes.

[0066] Please refer to this as well. Figures 1 to 5 The switch container 4 is equipped with a sealed electrical connection structure 8, which includes a stainless steel shell welded to the switch container 4 and an insulating sealant filled inside the stainless steel shell. The stainless steel shell is welded to the switch container 4 to form an integral metal sealed structure. The insulating sealant, typically made of low-temperature insulating materials such as epoxy resin, fills the interior of the stainless steel shell. The current lead of the superconducting switch 5 passes through the insulating sealant, with one end connected to the superconducting switch 5 inside the switch container 4 and the other end connected to an external circuit.

[0067] This design ensures both the reliability of the electrical connection and the airtightness of the switch container 4 in low-temperature environments, preventing leakage of the gas medium 6. The insulating seal exhibits excellent insulation performance and mechanical strength at low temperatures, and can withstand the thermal stress caused by temperature changes.

[0068] In some embodiments, the device further includes a first temperature probe 9, a second temperature probe 10, and a third temperature probe 11; the first temperature probe 9 is disposed on the sealed electrical connection structure 8 of the switch container 4; the second temperature probe 10 is disposed on the bottom of the switch container 4; and the third temperature probe 11 is disposed on the outer surface of the superconducting switch 5.

[0069] Please refer to this as well. Figures 1 to 5 The conductive cooling superconducting magnet also includes a first temperature probe 9, a second temperature probe 10, and a third temperature probe 11. The first temperature probe 9 is mounted on the sealed electrical connection structure 8 of the switch container 4, specifically fixed to the stainless steel casing of the sealed electrical connection structure 8, and is used to monitor the temperature of the sealed electrical connection structure 8 and the vicinity of the current leads. The second temperature probe 10 is located at the bottom of the switch container 4 and is used to monitor the overall temperature of the switch container 4. The third temperature probe 11 is located on the outer surface of the superconducting switch 5 and directly monitors the temperature of the superconducting switch 5 itself.

[0070] During the excitation process, the state of the superconducting switch 5 can be accurately determined by monitoring the temperature changes of the three temperature probes: when the temperature displayed by the third temperature probe 11 rises above the critical temperature of the superconducting switch 5, it indicates that the superconducting switch 5 has been successfully opened; when the temperature of the third temperature probe 11 and the second temperature probe 10 drops below the critical temperature, it indicates that the superconducting switch 5 has cooled and closed. These temperature signals are transmitted to an external control system for automatic control.

[0071] In some embodiments, the switch container 4 is provided with a sealing member 12, the sealing member 12 comprising:

[0072] The housing 1201 has an internal cavity, and one end of the housing 1201 is connected to the interior of the switch container 4;

[0073] The sealing core 1202 is movably disposed in the cavity inside the housing 1201;

[0074] The sealing flange 1203 is located at the end of the housing 1201 away from the switch container 4;

[0075] The outer sealing plate 1204 is detachably fixed to the sealing flange 1203;

[0076] The sealing ring 1205 is located between the sealing flange 1203 and the outer sealing plate 1204.

[0077] Please refer to this as well. Figures 1 to 4 The switch container 4 is provided with a sealing element 12, which is used to fill the switch container 4 with gas medium 6 and achieve sealing after filling.

[0078] The sealing component 12 includes a housing 1201, a sealing core 1202, a sealing flange 1203, an outer sealing plate 1204, and a sealing ring 1205. The housing 1201 has an internal cavity, and one end of the housing 1201 is in sealed communication with the interior of the switch container 4. The sealing core 1202 is movably disposed within the cavity inside the housing 1201 and can move axially along the cavity. The sealing flange 1203 is located at the end of the housing 1201 away from the switch container 4. The outer sealing plate 1204 is detachably fixed to the sealing flange 1203, typically by bolts. The sealing ring 1205 is disposed between the sealing flange 1203 and the outer sealing plate 1204.

[0079] When inflating at room temperature, first remove the outer sealing plate 1204, then use a tool to remove the sealing core 1202, and then connect the external gas medium 6 pipeline to the sealing flange 1203. After sufficient gas medium 6 is introduced, insert the sealing core 1202 and seal it with the outer sealing plate 1204. Fix the outer sealing plate 1204 to the sealing flange 1203 with bolts, and tighten the sealing ring 1205 to achieve a seal. The sealing ring 1205 is preferably a metal sealing ring 1205, which can withstand low temperatures and has good sealing performance at low temperatures.

[0080] In some embodiments, the system further includes a cryogenic container 13 and a cold shield 14. The cryogenic container 13 is wrapped around the outside of the cold shield 14, which is wrapped around the outside of the switch container 4, the superconducting coil 2, and the superconducting connector 201, and is thermally connected to the first-stage cold head 101 of the refrigerator cold head 1, for absorbing heat radiated from the room temperature environment to the cryogenic region.

[0081] Please refer to this as well. Figures 1 to 4 The conductive cooling superconducting magnet also includes a cryogenic container 13 and a cold shield 14. The cryogenic container 13 is a large vacuum container that surrounds the entire magnet and is used to provide a vacuum insulation environment to reduce the conduction and convection of external heat to the cryogenic components.

[0082] A cold shield 14 is disposed inside the cryogenic container 13, enclosing the switch container 4, the superconducting coil 2, and the superconducting connector 201. The cold shield 14 may be made of a thin sheet of highly reflective metal (such as a copper or aluminum plate), and its surface may be polished to reduce thermal radiation absorption. The cold shield 14 is thermally connected to the first-stage cold head 101 of the cryogenic cold head 1 and is cooled to approximately 50K.

[0083] The function of the cooling screen 14 is to absorb the heat radiated from the room temperature environment to the low temperature region (4K). Since the temperature of the cooling screen 14 (50K) is much lower than the room temperature (300K), the amount of heat radiated to the internal 4K components is extremely low, thereby effectively protecting the internal superconducting components and reducing the heat load on the second-stage cooling head 102.

[0084] In some embodiments, the sealing element 12 is located inside the cold shield 14.

[0085] Please refer to this as well. Figure 1 and Figure 3 In this embodiment, the sealing element 12 is located inside the cold shield 14, meaning that the sealing element 12 is entirely disposed within the space enclosed by the cold shield 14, and both the switch container 4 and the sealing element 12 on it are in the 50K temperature range. This arrangement is suitable for scenarios where the sealing element 12 itself can withstand low-temperature operating conditions, and the sealing ring 1205 is made of low-temperature resistant materials such as metal sealing ring 1205. The inflation and sealing operations of the sealing element 12 need to be completed before the magnet cools down (i.e., at room temperature). After cooling down, the sealing element 12 enters the low-temperature environment together with the switch container 4.

[0086] In some embodiments, the end of the sealing member 12 away from the switch container 4 extends through the cold shield 14 and the cryogenic container 13 to the outside of the cryogenic container 13.

[0087] Please refer to Figure 5 In this embodiment, the end of the sealing member 12 away from the switch container 4 extends through the cold shield 14 and the cryogenic container 13 to the outside of the cryogenic container 13. Specifically, the sealing member 12 extends outward from the switch container 4, passing through the walls of the cold shield 14 and the cryogenic container 13 in sequence. The end away from the switch container 4 (i.e., the end where the sealing flange 1203 and the outer sealing plate 1204 are provided) is located outside the cryogenic container 13 and is in a room temperature environment.

[0088] With this configuration, the inflation and sealing operations of the sealing element 12 are always performed at room temperature, eliminating the need for operation in low-temperature environments. Operators can complete the inflation of the gas medium 6 and the installation of the sealing core 1202 at room temperature, making the operation more convenient and safer. The inflation and sealing operations are simple and reliable, and maintenance is easy. Furthermore, since the end of the sealing element 12 furthest from the switch container 4 is at room temperature, the sealing ring 1205 does not need to withstand extremely low temperatures, allowing for the use of a wider range of sealing materials and sealing methods (such as conventional rubber sealing rings), resulting in higher sealing reliability.

[0089] In some embodiments, the gas medium 6 is helium, and the filling pressure of the gas medium 6 in the switch container 4 at room temperature is 1 standard atmosphere.

[0090] Please refer to this as well. Figures 1 to 5 This embodiment provides a detailed description of the specific selection and filling parameters of the gas medium 6. The gas medium 6 is helium because helium does not condense in the 4K temperature range and has extremely high specific heat capacity and good thermal conductivity. When the superconducting magnet operates in a higher temperature range (e.g., using high-temperature superconducting materials), other gases with suitable boiling points, or mixtures of multiple gases, can also be used.

[0091] The filling pressure of the gas medium 6 inside the switch container 4 at room temperature (approximately 300K) can be selected as 1 standard atmosphere (approximately 101.325 kPa). The filling volume can be adjusted according to the volume of the switch container 4 and design requirements, and is not specifically limited. The volume of the switch container 4 is also not specifically limited and can be designed according to the size of the superconducting switch 5 and the required cold storage capacity.

[0092] In some embodiments, please refer to the following: Figures 1 to 5 The conductive cooling superconducting magnet also includes a first pull rod 15 and a second pull rod 16. Both the first pull rod 15 and the second pull rod 16 are made of a high-strength, low-thermal-conductivity material, such as glass fiber reinforced composite material. One end of the first pull rod 15 is fixed to the cryogenic container 13, and the other end is fixed to the superconducting coil 2, for supporting and fixing the superconducting coil 2. One end of the second pull rod 16 is fixed to the cryogenic container 13, and the other end is fixed to the switching container 4, for supporting and fixing the switching container 4. The low thermal conductivity of the first pull rod 15 and the second pull rod 16 effectively reduces heat leakage from the room temperature end to the cryogenic end.

[0093] In addition, the superconducting magnet is equipped with multiple current leads for connecting the external power supply, the superconducting switch 5 and the superconducting coil 2, specifically including lead 17, lead 28, lead 319, lead 420, lead 521, lead 622, lead 723, lead 824, lead 925 and lead 1026.

[0094] The excitation and closed-loop operation process of the conductive cooling superconducting magnet of the present invention during operation is as follows:

[0095] First, the heater on the superconducting switch 5 is activated to heat the switch. The heat generated by the superconducting switch 5 is absorbed by the gas medium 6 inside the switch container 4, and some of the heat is conducted to the switch container 4 through the gas medium 6, and then to the second-stage cold head 102 via the second heat transfer connector 7. When the temperature of the superconducting switch 5 rises above its critical temperature, the superconducting switch 5 changes from the superconducting state to the normal state (open state).

[0096] Then, current is output from the positive terminal of the external power supply, and leads 17, 18, 19, and 20 into one of the superconducting connectors 201, then into the superconducting coil 2, and finally out through the other superconducting connector 201, flowing through leads 26, 24, 23, and 22 into the negative terminal of the external power supply, forming an excitation circuit. During the excitation process, the superconducting switch 5 remains open.

[0097] After excitation is completed, the heater of the superconducting switch 5 is turned off. The gas medium 6 in the switch container 4 conducts the residual heat of the superconducting switch 5 to the switch container 4, and is absorbed by the cold head through the second heat transfer connector 7; at the same time, the gas medium 6 itself is also cooled by the cold head through the wall of the switch container 4, and the temperature drops rapidly.

[0098] By monitoring the temperature probe, when the temperature of superconducting switch 5 drops below the critical temperature, superconducting switch 5 automatically returns to the superconducting state (closed state). At this time, the current in leads 17, 18, 19, 24, 23, and 22 is reduced to 0A by an external power supply. Simultaneously, the current forms a closed loop through lead 20, superconducting coil 2, lead 26, lead 25, superconducting switch 5, and lead 21, and the superconducting magnet enters a continuous operation mode.

[0099] It should be noted that in this specification, relational terms such as first and second are used only to distinguish one entity from several other entities, and do not necessarily require or imply any such actual relationship or order between these entities.

[0100] This article uses specific examples to illustrate the principles and implementation methods of the present invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principles of the present invention, and these improvements and modifications also fall within the protection scope of the present invention.

Claims

1. A conductive cooling superconducting magnet, characterized in that, include: The refrigerator cold head (1) has a second-stage cold head (102) for providing cooling capacity at the superconducting operating temperature; Superconducting coil (2) and superconducting connector (201); The first heat transfer connector (3) connects the second stage cold head (102) of the refrigerator cold head (1) to the superconducting coil (2) and the superconducting connector (201); Switch container (4); A superconducting switch (5) is sealed inside the switch container (4); A gaseous medium (6) is filled inside the switch container (4) and encapsulates the superconducting switch (5); The second heat transfer connector (7) connects the switch container (4) to the second stage cold head (102) of the refrigerator cold head (1), and the second heat transfer connector (7) and the first heat transfer connector (3) meet at the second stage cold head (102) of the refrigerator cold head (1); The heat generated by the superconducting switch (5) is first transferred to the gas medium (6) that encloses the superconducting switch (5) through heat exchange. The gas medium (6) then exchanges heat with the switch container (4). The heat is transferred sequentially through the gas medium (6), the switch container (4), and the second heat transfer connector (7) to the second stage cold head (102) of the refrigerator cold head (1). After the heating of the superconducting switch (5) is stopped, the cooling capacity of the second-stage cold head (102) of the refrigerator cold head (1) is transferred to the superconducting switch (5) via the second heat transfer connector (7), the switch container (4) and the gas medium (6) along a path opposite to the heat transfer direction.

2. The conductive cooling superconducting magnet according to claim 1, characterized in that, The second heat transfer connector (7) includes a connecting block (701) and a heat transfer connector (702); the connecting block (701) is made of a high thermal conductivity material and is fixedly connected to the switch container (4); one end of the heat transfer connector (702) is connected to the connecting block (701), and the other end is connected to the second stage cold head (102) of the refrigerator cold head (1).

3. The conductive cooling superconducting magnet according to claim 1, characterized in that, The second heat transfer connector (7) includes a heat transfer connector (702), one end of which is connected to the switch container (4), and the other end is connected to the second stage cold head (102) of the refrigerator cold head (1).

4. The conductive cooling superconducting magnet according to claim 1, characterized in that, The switch container (4) is provided with a sealed electrical connection structure (8), which includes a stainless steel shell welded to the switch container (4) and an insulating seal filled in the stainless steel shell. The current lead of the superconducting switch (5) passes through the insulating seal.

5. The conductive cooling superconducting magnet according to claim 4, characterized in that, It also includes a first temperature probe (9), a second temperature probe (10) and a third temperature probe (11); the first temperature probe (9) is disposed on the sealed electrical connection structure (8) of the switch container (4); the second temperature probe (10) is disposed on the bottom of the switch container (4); and the third temperature probe (11) is disposed on the outer surface of the superconducting switch (5).

6. The conductive cooling superconducting magnet according to any one of claims 1 to 5, characterized in that, The switch container (4) is provided with a sealing element (12), the sealing element (12) comprising: The housing (1201) has an internal cavity, and one end of the housing (1201) is connected to the interior of the switch container (4); The sealing core (1202) is movably disposed in the cavity inside the housing (1201); A sealing flange (1203) is disposed at the end of the housing (1201) away from the switch container (4); The outer sealing plate (1204) is detachably fixed to the sealing flange (1203); A sealing ring (1205) is disposed between the sealing flange (1203) and the outer sealing plate (1204).

7. The conductive cooling superconducting magnet according to claim 6, characterized in that, It also includes a cryogenic container (13) and a cold shield (14), the cryogenic container (13) being wrapped around the outside of the cold shield (14), the cold shield (14) being wrapped around the outside of the switch container (4), the superconducting coil (2) and the superconducting connector (201), and being thermally connected to the first-stage cold head (101) of the refrigerator cold head (1) for absorbing heat radiated from the room temperature environment to the cryogenic region.

8. The conductive cooling superconducting magnet according to claim 7, characterized in that, The sealing element (12) is located inside the cold screen (14).

9. The conductive cooling superconducting magnet according to claim 7, characterized in that, The end of the sealing element (12) away from the switch container (4) extends through the cold shield (14) and the cryogenic container (13) to the outside of the cryogenic container (13).

10. The conductive cooling superconducting magnet according to claim 1, characterized in that, The gas medium (6) is helium, and the filling pressure of the gas medium (6) in the switch container (4) at room temperature is 1 standard atmosphere.

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