Conductive cooling superconducting magnet cold mass assembly and its manufacturing method

Abstract

This invention relates to a conductive cooling superconducting magnet cold mass assembly and its manufacturing method, comprising an inner skeleton, a superconducting coil, and an outer skeleton assembly. End plate assemblies are respectively provided at both ends of the inner skeleton and the outer skeleton assembly, forming a closed cylindrical cavity. The outer skeleton assembly includes an outer skeleton and stainless steel rings located at both ends of the outer skeleton. The outer skeleton is made of a high thermal conductivity material. The outer surface of the outer skeleton has one or more mounting planes for mounting high thermal conductivity flexible connectors. The stainless steel rings have several mounting planes for mounting feet and electrical connection structural components. The manufacturing method is also disclosed. This invention integrates the self-support of the cold mass assembly, the electromagnetic force constraining the superconducting coil radially outward, and the heat transfer function into the outer skeleton assembly, improving the mechanical connection robustness between the feet and the cold mass, increasing heat transfer efficiency, simplifying the structure of the cold mass assembly, and making the manufacturing process easier to standardize.

Description

Technical Field

[0001] This invention relates to a superconducting magnet employing conductive cooling, a vertical single-sowary superconducting magnet for use in the field of superconducting magnetic separation, and a method for manufacturing the superconducting magnet, belonging to the field of superconducting magnet technology. Background Technology

[0002] Superconducting magnetic separation is a new magnetic separation method that applies superconducting technology to the field of magnetic separation. Superconducting magnetic separation uses superconducting materials as coils. When current is passed through the coils, they can generate a super-strong magnetic field in a large separation space. The coils consume almost no electrical energy, and the magnetic field does not decay over a long period of time. It is small in size, light in weight, and has a high single-machine processing capacity, and can be widely used in the separation of micro-magnetic minerals and low-magnetic minerals.

[0003] To ensure the normal operation of superconducting magnets, they must be cooled below their critical temperature. Near this critical temperature, especially in a liquid helium environment of 4.2K (-269℃), superconducting materials exhibit virtually no electrical resistance, demonstrating significant performance advantages. A dual-cylinder superconducting magnetic separator for kaolin, disclosed in Chinese Patent Publication No. CN102600970A, utilizes a liquid helium environment to cool the superconducting magnets.

[0004] With the increasing strategic value of helium, the total amount of helium available on the market is controlled by resource-exporting countries, leading to a significant increase in the testing and maintenance costs of superconducting magnets cooled by liquid helium. This greatly limits the large-scale production of emerging superconducting magnetic separation products. Therefore, liquid helium-free conductive cooling of superconducting magnet cold mass components has become an important development direction for such products.

[0005] Chinese patent publications CN204974166U (a liquid helium-free superconducting vertical pulsed high-gradient magnetic separator) and CN108273659A (a direct-cooling high-temperature superconducting magnetic separator) both disclose the general structural form of superconducting magnets using liquid helium-free conductive cooling. The cold mass assembly, as the core component, is designed with a superconducting coil wound within a U-shaped frame consisting of an inner cylinder and end plates. A binding layer of a certain thickness is wound around the outer surface of the superconducting coil to constrain the outward expansion of the electromagnetic force of the energized coil. The cold mass of a superconducting magnet refers to the sum of all objects at the same temperature as the superconducting coil, a common term in the field of superconducting magnets. The entire cold mass is fixed within a vacuum container by a suspension support structure; the cold mass, along with the suspension support structure, is referred to as the cold mass assembly in this patent. Because the U-shaped frame supports the superconducting coil on its inner side in the diametrical direction, it is also called the inner frame. For the aforementioned cold mass structure, the cold end load of the suspension support mainly acts on the inner frame. Its disadvantage is that tightening the suspension support affects the internal force distribution of the coil, which can easily cause superconducting magnet training and degradation, requiring additional reinforcement structures on the cold mass. Superconducting magnet training and degradation refer to the phenomenon where a superconducting magnet, upon initial excitation after manufacturing, fails to reach the predetermined magnetic field and instead transitions from a superconducting state to a normally conducting state during excitation. Some magnets can stably approach the predetermined magnetic field after several excitations; this is called superconducting magnet training. Other magnets can only stabilize at a magnetic field much lower than the predetermined value; this is called superconducting magnet degradation.

[0006] Besides applying pre-tightening force to the suspended support structure during manufacturing, the load-bearing points on the cold mass where the superconducting coils are located in the superconducting magnetic separator come from two aspects: 1. Forces in various directions during transportation. After the superconducting magnetic separator is manufactured in the factory, it needs to be transported long distances to the site of use. During transportation, it will experience forces in various directions generated during various transportation processes such as starting, stopping, braking, turning, and bumping. That is, the load-bearing points on the cold mass need to withstand acceleration in three dimensions; 2. During the use of the superconducting magnetic separator, the magnetic adsorption and release of magnetic materials are usually achieved by moving the magnetic medium into and out of the magnetic field. The load-bearing points on the cold mass need to withstand periodic axial unbalanced forces.

[0007] Currently, conductive superconducting magnets mainly rely on the cooling capacity of small helium refrigerators to cool the cold mass containing the superconducting coils. Due to the limited cooling power of helium refrigerators, the time for the cold mass to cool from room temperature to operating temperature is relatively long. Furthermore, the total mass of the cold mass itself affects the cooling efficiency. That is, with the same cooling power, the larger the total mass of the cold mass, the slower the overall cooling rate and the longer the total cooling time. This will also affect the preparation time of the entire superconducting magnetic separation equipment from startup to operation, resulting in a poorer user experience. Therefore, it is necessary to strictly control the total mass of the cold mass.

[0008] Therefore, for the cold mass component of the superconducting magnet with conductive cooling, a reasonable structural design is required to minimize the total mass of the cold mass while improving the strength of the fixed structure. This will ensure that the cold mass of the superconducting magnet can be reliably and stably installed in the superconducting magnetic separator, operate reliably and stably, and improve start-up efficiency while reducing preparation time. Summary of the Invention

[0009] The purpose of this invention is to provide a conductive cooling superconducting magnet cold mass assembly and its manufacturing method, in order to change the current installation method of superconducting coils in conductive cooling superconducting magnet cold mass assemblies, thereby improving the manufacturing efficiency of the equipment, enhancing the reliability of the entire superconducting magnet cold mass installation structure, and reducing the total mass of the cold mass.

[0010] To achieve the above-mentioned objectives, in a first aspect, the present invention provides a conductive cooling superconducting magnet cold mass assembly, which is composed of an inner skeleton cylinder, a superconducting coil, and an outer skeleton assembly from the inside out along the diameter direction of the magnetic cavity;

[0011] The inner and outer skeleton components are respectively provided with end plate assemblies at both ends; the inner skeleton, outer skeleton components, and end plate assemblies on both sides form a closed cylindrical cavity, and the superconducting coil is located inside the cylindrical cavity;

[0012] The outer surface of the inner cylinder of the skeleton is provided with a polymer insulating layer, and the superconducting coil is wound around the polymer insulating layer.

[0013] The end plate assembly consists of two layers of plates, with the outer layer being a metal end plate and the inner layer being an insulating end plate.

[0014] The inner ring of the metal end plate is connected and fixed to the inner cylinder of the skeleton, and the outer ring of the metal end plate is connected and fixed to the outer skeleton assembly.

[0015] The insulating end plate is in contact with the polymer insulating layer to insulate and wrap the superconducting coil.

[0016] The exoskeleton assembly includes an exoskeleton and stainless steel rings located at both ends of the exoskeleton;

[0017] The outer frame is made of a highly thermally conductive material;

[0018] The stainless steel rings are respectively provided at the openings at both ends of the outer frame;

[0019] The inner wall of the stainless steel ring is connected to the outer wall of the end of the outer frame; the connection between the two is brazed together.

[0020] The outer frame assembly, consisting of the outer frame and stainless steel rings at both ends, has a straight cylindrical inner side for storing superconducting coils.

[0021] The superconducting coil is provided with an insulating material layer; the two ends of the outer frame assembly have shallow grooves extending outwards, the two ends of the insulating material layer extend beyond the ends of the superconducting coil, and the portion of the insulating material layer extending beyond the ends of the superconducting coil is folded outwards and stored in the shallow grooves; the insulating end plate covers part or all of the outwardly folded portion of the insulating material located in the shallow grooves.

[0022] The outer surface of the exoskeleton assembly is provided with several mounting planes, and the mounting planes are provided with mounting screw holes.

[0023] The outer surface of the outer frame is provided with one or more mounting planes, and a high thermal conductivity flexible connector is mounted on the mounting plane of the outer frame; the high thermal conductivity flexible connector is used to connect the external helium refrigerator and the outer frame;

[0024] The stainless steel ring has several mounting surfaces, on which legs and electrical connection structural components are mounted.

[0025] The support has 8 feet, which are located on the stainless steel rings on both sides respectively; the support feet on the stainless steel rings on both sides are arranged inwards relative to each other along the magnetic cavity axis; each stainless steel ring on each side has 4 feet, which are evenly distributed along the magnetic cavity axis.

[0026] The insulating end plate is provided with a wire passage groove;

[0027] The center tap and / or lead of the superconducting coil passes through the wire groove on the insulating plate to reach the outer surface of the outer frame assembly, and is then connected to the electrical connection component.

[0028] As a further improvement of the present invention, the outer ring of the metal end plate is provided with mounting holes, and the stainless steel ring is provided with end plate mounting screw holes; the screw passes through the mounting holes on the metal end plate and is screwed into the end plate mounting screw holes on the stainless steel ring to fix the metal end plate on the stainless steel ring.

[0029] The inner side of the metal end plate is integrally formed or welded to the inner cylinder of the skeleton.

[0030] As a further improvement of the present invention, the inner cavity of the stainless steel ring consists of two straight cylinders of different sizes along the axial direction.

[0031] The small-diameter straight cylinder is located on the outside, and its inner diameter is equal to the inner diameter of the straight cylinder inside the outer skeleton.

[0032] The large-diameter straight cylinder is located on the inside;

[0033] The outer frame has circular grooves on both ends;

[0034] The inner diameter of the large-diameter straight cylinder inside the stainless steel ring is equal to the outer diameter of the circular grooves at both ends of the outer frame.

[0035] The stainless steel ring is fitted onto the circular grooves at both ends of the outer frame via a large-diameter straight cylindrical sleeve.

[0036] Furthermore, the stainless steel ring is brazed to fix the contact area with the outer frame.

[0037] Furthermore, the wall thickness of the small-diameter straight cylindrical part of the inner cavity of the stainless steel ring is equal to the wall thickness of the middle skeleton part of the outer skeleton.

[0038] Furthermore, the wall thickness of the inner cavity of the stainless steel ring, where the large-diameter straight cylindrical part is located, is half the wall thickness of the middle skeleton part of the outer skeleton.

[0039] As a further improvement of the present invention, the shallow groove provided on the open end of the stainless steel ring has a groove width of 3-5 mm and a groove depth greater than 0.5 mm.

[0040] A transition chamfer is provided between the shallow groove and the inner wall of the stainless steel ring. The transition chamfer is a circular arc transition with a radius greater than 0.5 mm and less than 1 mm.

[0041] As a further improvement of the present invention, each leg includes a leg base and a support rod;

[0042] The support base has a mounting surface, and the mounting surface is provided with a plurality of mounting holes;

[0043] The stainless steel ring has several corresponding mounting screw holes in the support mounting plane.

[0044] Stainless steel screws are screwed through the mounting holes on the support base and into the mounting screw holes on the stainless steel ring to fix the support base to the stainless steel ring;

[0045] The support leg is provided with a support rod seat, and the support rod seat is provided with a support rod hole;

[0046] One end of the support rod is inserted into the support rod hole and fixed by a threaded connection structure;

[0047] The support rod is positioned inward along the axis of the magnetic cavity and outward along the diameter of the magnetic cavity;

[0048] The other end of the support rod is provided with a mounting part for connecting to external equipment.

[0049] A second aspect of the present invention provides a method for manufacturing the above-described conductive cooling superconducting magnet cold mass assembly:

[0050] Step 1: Preparation;

[0051] Prepare the outer frame assembly; install and fix the two stainless steel rings at both ends of the outer frame;

[0052] Prepare the support legs, highly thermally conductive flexible connectors, and electrical connection structure components;

[0053] Prepare the skeleton inner cylinder, superconducting wire for the superconducting coil, and end plate components;

[0054] Step 2, winding;

[0055] A polymer insulation layer is installed on the inner cylinder of the skeleton;

[0056] Place the fixed insulating end plate in place, attach it to the fixed metal end plate, and make contact with the polymer insulating layer;

[0057] The movable metal end plate and the movable insulating end plate are assembled together onto the open end of the inner cylinder of the skeleton to form a winding skeleton.

[0058] The winding frame is installed on the winding machine, and the superconducting wire is wound onto the winding frame to gradually form a superconducting coil.

[0059] During the winding process, the middle tap and / or lead end of the superconducting coil are left on one side of the fixed end plate of the winding frame and inserted into the wire groove on the fixed insulating end plate, leaving the end on the outside.

[0060] After the winding is completed, remove the winding frame with the superconducting coil wound on it; remove the movable metal end plate and the movable insulating end plate;

[0061] Insulating material is wrapped around the outside of the superconducting coil; and a certain length of insulating material is reserved at both ends of the superconducting coil. That is, the insulating material on the side closer to the fixed insulating end plate is turned up outward along the inner plane of the fixed insulating end plate, turning up 3-5mm; while the insulating material on the side closer to the movable insulating end plate is wound around the outer surface of the superconducting coil in a cylindrical shape, and extends beyond the outer surface of the superconducting coil ring, leaving a length of 3-5mm to form an insulating material cylinder.

[0062] The outer diameter of the entire superconducting coil assembly after the insulating material is wound is smaller than the inner diameter of the outer frame assembly;

[0063] Step 3: Assemble the superconducting coil assembly into the outer frame assembly;

[0064] The superconducting coil, which is wound with insulating material, is connected to the inner cylinder of the skeleton, the fixed metal end plate, and the fixed insulating end plate, and installed from one end of the outer skeleton assembly;

[0065] The insulating material near the fixed insulating end plate is flipped up 3-5mm and inserted into the shallow groove of the stainless steel ring on that side during the installation process.

[0066] Leave the center tap and / or the end of the lead of the superconducting coil outside the stainless steel ring of the outer frame assembly.

[0067] During installation, adjust the angle of the fixed metal end plate so that the end plate mounting through hole on the fixed metal end plate is aligned with the end plate mounting hole on the stainless steel ring.

[0068] After the inner skeleton cylinder and superconducting coil are installed in the outer skeleton assembly, fastening screws are inserted into the end plate mounting through holes of the fixed metal end plate and screwed into the end plate mounting holes of the stainless steel ring to fix the inner skeleton cylinder, superconducting coil, fixed metal end plate, and fixed insulating end plate together onto the stainless steel ring of the outer skeleton assembly.

[0069] At the open end of the inner cylinder of the skeleton, the insulating material extending 3-5 mm beyond the length reserved for the superconducting coil is turned outward and placed into the shallow groove of the stainless steel ring on that side.

[0070] At the open end of the inner cylinder of the skeleton, cover the movable metal end plate and movable insulating end plate that were removed in step 2; attach the movable insulating end plate to the superconducting coil cover, and then cover the movable metal end plate;

[0071] Adjust the position of the movable metal end plate so that its end plate mounting through hole is aligned with the end plate mounting hole of the stainless steel ring. Then, insert the fastening screw into the end plate mounting through hole of the movable metal end plate and screw it into the end plate mounting hole of the stainless steel ring to fix the movable metal end plate and the movable insulating end plate on the stainless steel ring of the outer frame assembly.

[0072] Step 4: Welding and fixing of the movable metal end plate;

[0073] The movable metal end plate is connected to the inner cylinder of the skeleton by welding;

[0074] Argon arc welding is used for welding. First, multiple points are selected for intermittent welding around the circumference. Then, two symmetrical welds on the circumference are grouped together and welded sequentially in a manner that ensures uniform welding stress.

[0075] During welding, the depth and width of the weld pool should not exceed 2mm;

[0076] Step 5: Assemble the outer structure of the exoskeleton assembly;

[0077] Install the leg fittings onto the stainless steel ring of the outer frame assembly in sequence;

[0078] Assemble the high thermal conductivity flexible connectors onto the outer wall of the outer frame, that is, fix the frame connecting plate to the outer wall of the outer frame, and arrange the outward connecting plate and flexible connecting plate.

[0079] Install the electrical connection structure onto the stainless steel rings, that is, install the center tap terminal block, and / or coil lead terminal block, and quench protection diode assembly onto the outer wall of the outer frame assembly, and tighten the fasteners onto the stainless steel rings at both ends; connect the center tap and / or lead end of the superconducting coil to the corresponding electrical connection structure.

[0080] This completes the manufacturing of the aforementioned conductive cooling superconducting magnet cold mass assembly.

[0081] As a further improvement of the present invention, in step 3 above, during the installation of the superconducting coil assembly in the outer frame assembly, and after the installation is in place, epoxy resin is filled in the gap between the outermost insulating material wrapped around the superconducting coil and the inner hole of the outer frame assembly.

[0082] The conductive cooling superconducting magnet cold mass assembly of the present invention further standardizes the manufacturing process, making it faster and more convenient. Furthermore, with the use of an outer frame, combined with stainless steel rings and feet at both ends, the entire cold mass can be robustly and reliably installed into the superconducting magnet. The staggered, multi-directionally arranged feet fully withstand forces from all directions.

[0083] The cold mass of a superconducting magnet is a core component of the superconducting magnet and even superconducting magnetic separation equipment. Unlike traditional cold mass structures that use an inner frame to transfer cold energy and support the core component, this invention adopts a unique outer frame assembly structure, making the outer frame assembly the core component of the entire cold mass. This has the following outstanding advantages:

[0084] 1. The outer frame is made of a high thermal conductivity material and is a thick-walled cylinder. It is used to transfer cold energy, which helps to ensure the temperature uniformity along the entire length of the superconducting coil. At the same time, the thermal contraction of the high thermal conductivity material from room temperature to operating temperature (less than 4K, -269.15℃) is greater than the thermal contraction of the superconducting coil itself. This helps to resist the electromagnetic force of the energized superconducting coil expanding outward in the diameter direction, maintain the mutual compression between the superconducting wires, reduce the number of times the superconducting coil is energized, and shorten the equipment manufacturing cycle.

[0085] 2. The electromagnetic force of the superconducting coil expanding outward in the diameter direction is distributed in the axial direction with a high middle and low two ends. Therefore, although stainless steel rings are used at both ends of the outer frame, the amount of cold shrinkage of the stainless steel rings is relatively small, thus reducing the amount of cold shrinkage of the entire outer frame assembly at both ends. However, it is still sufficient to resist the electromagnetic force of the superconducting coil expanding outward and maintain the state of mutual compression between the superconducting wires.

[0086] 3. Except for the high thermal conductivity flexible connectors, all mechanical connections on the end face and outer surface of the outer frame are fixed to the stainless steel rings at both ends, avoiding the use of threaded connections in the relatively soft high thermal conductivity metal outer frame, making the connection structure more robust and reliable.

[0087] 4. The shallow grooves at both ends of the outer frame increase the creepage distance between it and the superconducting coil, ensuring the integrity of the superconducting coil's insulation to ground;

[0088] 5. The exoskeleton can be prefabricated, which can greatly shorten the manufacturing time of superconducting magnets compared with the winding form of structural reinforcement layer;

[0089] 6. The outer skeleton assembly, consisting of the outer skeleton and the stainless steel rings at both ends, integrates all the functions of the cold mass in terms of thermodynamics and structural mechanics; thus simplifying the structure of the cold mass, achieving the final effect of reducing the total mass of the cold mass, and thereby shortening the cooling preparation time of the superconducting equipment. Attached Figure Description

[0090] Figure 1 This is a schematic diagram of the overall structure of the conductive cooling superconducting magnet cold mass assembly of the present invention;

[0091] Figure 2 This is an internal cross-sectional view of the conductive cooling superconducting magnet cold mass assembly of the present invention;

[0092] Figure 3 This is a top view of the conductive cooling superconducting magnet cold mass assembly of the present invention;

[0093] Figure 4 This is a schematic diagram of the overall structure of the exoskeleton component of the present invention;

[0094] Figure 5 This is an internal sectional view of the exoskeleton assembly of the present invention;

[0095] Figure 6 This is a schematic diagram of the mounting of the support legs of the present invention on the outer frame;

[0096] Figure 7 This is a schematic diagram of the mounting of the support base of the present invention on a stainless steel ring. Detailed Implementation

[0097] The specific embodiments of the present invention will be further described in detail below with reference to the accompanying drawings.

[0098] The conductive cooling superconducting magnet cold mass assembly of the present invention, firstly, as... Figure 1 , Figure 2 , Figure 3 As shown, the cold mass as a whole is composed of an inner frame cylinder 1, a superconducting coil 2, and an outer frame assembly (including an outer frame 3 and a stainless steel ring 4) from the inside out along the diameter direction of the magnetic cavity. The inner frame cylinder 1 and the outer frame assembly are respectively provided with end plates 4 for connection and fixation, forming a closed cylindrical cavity to accommodate the superconducting coil 2.

[0099] Two end plates 4 are provided. One end plate 4 is pre-fixed to the inner cylinder 1 of the skeleton and is called the fixed metal end plate 41. The fixed metal end plate 41 can also be directly pre-fabricated on the inner cylinder 1 by machining. The other end plate 4 is connected to the inner cylinder 1 of the skeleton during the winding of the superconducting wire and is fixed by tooling. It is called the movable metal end plate 43. The inner cylinder 1 of the skeleton and the end plates 4 on both sides form the winding skeleton (I-beam) of the superconducting coil 2. According to the design requirements, a polymer film is pasted on the winding skeleton as electrical insulation for the inner ring surface of the superconducting coil. Then, the superconducting wire is wound to finally form the superconducting coil 2. The lead wire of the superconducting coil 2 and the middle tap of the coil are left on one side of the fixed metal end plate of the skeleton. The inner cylinder 1 of the skeleton for winding the skeleton is made of austenitic stainless steel.

[0100] After the superconducting coil 2 is wound, the movable metal end plate 43 on the winding frame is removed; then, insulating material is wrapped around the outer surface of the superconducting coil 2, and the insulating material is tightly wrapped around the outer surface of the superconducting coil 2; at both ends of the superconducting coil 2, a certain length of insulating material is reserved, that is, the insulating material on the side near the fixed metal end plate 41 is turned outward along the inner plane of the fixed metal end plate 41, turning up 3-5mm; while the insulating material on the side near the movable metal end plate 43, since the movable metal end plate 43 has been removed at this time, is wound cylindrically along the outer surface of the superconducting coil 2, and extends beyond the outer surface of the ring of the superconducting coil 2, leaving a length of 3-5mm to form an insulating material cylinder.

[0101] The winding process of the superconducting coil 2 is consistent with the existing winding process of superconducting coils for superconducting magnets. However, in this invention, the winding frame (or I-beam) adopts a special structural design, which is a special frame inner cylinder 1 and end plate 4 (fixed on one side and movable on the other side).

[0102] Furthermore, the end plate 4 is composed of two layers of plates, with the outer side being a metal end plate and the inner side being an insulating end plate. The metal end plate is welded to the inner cylinder 1 of the skeleton and connected and fixed to the outer skeleton 3 to provide structural support.

[0103] The insulating end plates are made of polymer and serve as insulation. Furthermore, before the superconducting coil 2 is wound, the inner cylinder 1 of the skeleton is also first wound or coated with insulating material to form a polymer insulating layer. Before the superconducting coil 2 is wound, the insulating end plate on the side near the fixed metal end plate 41 needs to be placed in advance. This insulating end plate is called the fixed insulating end plate 42. The insulating end plate on the side of the movable metal end plate 43 also needs to be pre-placed when the superconducting coil 2 is wound to limit the end position of the superconducting coil 2. This insulating end plate is called the movable insulating end plate 44. Finally, the fixed insulating end plate 42 and the movable insulating end plate 44 are in contact with the polymer insulating layer on the inner cylinder 1 of the skeleton and the insulating material wound around the superconducting coil 2, forming all-round electrical insulation protection for the superconducting coil 2.

[0104] Furthermore, the fixed insulating end plate 42 is provided with several wire-passing grooves 45, and the leads and intermediate taps of the superconducting coil 2 are inserted into the wire-passing grooves 45, thereby leading to the outside of the outer frame 3 and connecting with the power supply and control equipment.

[0105] The key improvement of the conductive cooling superconducting magnet cold mass assembly of the present invention is that an outer frame assembly is provided outside the superconducting coil 2; in the current conventional cold mass manufacturing, after the superconducting coil 2 is wound, a filamentous high thermal conductivity material is wound around the superconducting coil 2 to strengthen and fix the coil.

[0106] The exoskeleton assembly of the present invention includes an exoskeleton 3, which is a metal cylinder open at both ends, specifically as follows: Figure 4 , Figure 5 As shown; the inner wall of the outer frame 3 is a cylindrical tube, and the inner diameter of the cylindrical tube matches the outer diameter of the superconducting coil 2 (the overall outer diameter after the insulating material is wound around it), which is used to accommodate the superconducting coil 2.

[0107] The outer frame 3 is connected to an external cold source to conduct cold energy to the superconducting coil 2 and cool the superconducting coil 2; therefore, the outer frame 3 is made of a high thermal conductivity material, such as T2 copper, T3 copper, H65~H80 brass, or aluminum-magnesium alloy, etc.

[0108] High thermal conductivity metals are generally relatively soft, resulting in poor structural strength for threaded connections. Therefore, this invention provides stainless steel rings 5 ​​at the openings at both ends of the outer frame 3; for example... Figure 6As shown, the stainless steel ring 5 has an L-shaped semi-vertical cross-section. Circular grooves 31 are provided on the outer sides of both ends of the outer frame 3. The stainless steel ring 5 is fitted into these grooves 31. The narrow ring portion 51 of the stainless steel ring 5 matches the circular groove 31 of the outer frame 3. The thick ring portion of the stainless steel ring 5 is fastened to both ends of the outer frame 3. The stainless steel ring 5 is brazed onto the outer frame 3. Preferably, the wall thickness of the circular groove 31 of the outer frame 3 is half the wall thickness of the inner portion. Correspondingly, the wall thickness of the narrow ring portion 51 of the stainless steel ring 5 is equivalent to the wall thickness of the circular groove 31 of the outer frame 3, both being half the wall thickness of the inner portion of the outer frame 3, or half the wall thickness of the thick ring portion of the stainless steel ring 5. The inner wall 52 of the thick ring portion of the stainless steel ring 5 is equal to and flush with the inner wall 32 of the outer frame 3 (at room temperature), and is used to match the outer diameter of the superconducting coil 2. Furthermore, the open end of the stainless steel ring 5 is provided with a shallow groove 53, the groove width of which is 3-5 mm and the groove depth is greater than 0.5 mm, for accommodating insulating material that extends beyond the outer ring surface of the superconducting coil 2; and a transition chamfer 54 is provided between the shallow groove 53 and the inner wall 52 of the thick ring, the transition chamfer 54 preferably being a circular arc transition with a radius greater than 0.5 mm and less than 1 mm.

[0109] The stainless steel ring 5 has an end plate mounting hole 55 along the axis of the outer frame 3 at its open end for fixing the end plate 4.

[0110] Furthermore, in addition to the cold mass, the present invention also includes structural components, as detailed below.

[0111] After the stainless steel ring 5 is fixed to the outer frame 3, they are machined together to form several mounting planes on the outer surface of the outer frame assembly, and several mounting screw holes are machined in the mounting planes for connecting and fixing external structural components.

[0112] The outer wall of the stainless steel ring 5 is provided with 8 mounting planes; on 4 of the spaced planes, there are a number of foot mounting holes for fixing and mounting feet 6.

[0113] The support leg 6 includes a support base 61, a support rod 62, and a fastener 63 for mounting the frame end; furthermore, as... Figure 7 As shown, the support base 61 is a stainless steel part with a mounting surface 611 and a mounting hole 612. A stainless steel screw is screwed into the support mounting hole on the stainless steel ring 5 through the mounting hole 612 to achieve fixation. The support base 61 has a support rod seat 613 on the outside. The support rod seat 613 has a support rod hole 614. One end of the support rod 62 is inserted into the support rod hole 614. The inserted end of the support rod 62 has an external thread. Then, a fastener 63, i.e. a nut, is screwed into the frame end to fix the support rod 62 on the support base 61.

[0114] Stainless steel rings 5 ​​are provided at both ends of the outer frame 3, and correspondingly, four support legs 6 are provided at each end. The support rods 62 of the support legs 6 at both ends are crossed and outwardly arranged. Each support rod 62 has a device mounting fastener 64 at its end for connection with the device, thus fixing the outer frame 3 inside the device. In particular, each support rod 62 is pulled across the stainless steel ring 5 at one end of the outer frame 3 to the stainless steel ring 5 at the other end, that is, the stainless steel ring 5 at the end of the outer frame 3 is pulled taut towards the inside of the outer frame 3. The cold mass is installed as a whole inside the device through the four support rods 62 at each end of the outer frame 3, which can withstand forces in all directions. The small contact area between the support rods 62 and the cold mass reduces the transfer of cold energy, allowing as much cold energy as possible to be retained within the cold mass.

[0115] An mounting surface is also provided on the outer wall of the outer frame 3, especially near the external helium refrigerator. A high thermal conductivity flexible connector is provided on the mounting surface. The high thermal conductivity flexible connector includes an outward connecting plate 71, a frame connecting plate 72, and a flexible connecting plate 73. The frame connecting plate 72 is installed on the mounting surface of the outer wall of the outer frame 3, and the outward connecting plate 71 is connected to the cold source output of the helium refrigerator. Preferably, there are two high thermal conductivity flexible connectors, which can be connected to two mounting surfaces of the outer frame 3 respectively, so as to efficiently transfer the cold source produced by the external helium refrigerator to the outer frame 3 and cool the entire cold mass.

[0116] An electrical connection structure is installed on the mounting surface of the stainless steel ring 5 without the support legs 6. Specifically, a coil lead connection plate 74 is provided on one of the surfaces for connecting to the leads on the superconducting coil 2; two symmetrical surfaces are provided with intermediate tap connection plates 75 for connecting to the intermediate taps on the superconducting coil 2; and a quench protection diode assembly 76 is provided on the last surface for setting the quench protection diode. The mechanical fixation of the relevant components of the electrical connection mechanism is mainly achieved by fasteners (screws), which are connected to the stainless steel rings 5 ​​at both ends of the outer frame 3, maintaining contact with the outer wall of the outer frame 3 at room temperature, but not fixed. The outer frame 3 is also set as a plane in the corresponding parts to increase the contact area with the electrical connection structure, thereby serving as an integral cold mass assembly to achieve synchronous and efficient cooling.

[0117] The manufacturing method of the conductive cooling superconducting magnet cold mass assembly of the present invention mainly includes:

[0118] 1. Preparation: Prepare the outer frame 3 in advance; install and weld the two stainless steel rings 5 ​​to both ends of the outer frame 3; prepare the accessories for the support legs 6, as well as the accessories for the high thermal conductivity flexible connectors and the accessories for the electrical connection structure.

[0119] Prepare the skeleton inner cylinder 1 (including the fixed metal end plate 41), the superconducting coil 2 with superconducting wire, the movable metal end plate 43, the fixed insulating end plate 42, and the movable insulating end plate 44;

[0120] Prepare the fasteners; prepare the assembly tools and welding equipment.

[0121] 2. Winding;

[0122] A polymer insulation layer is provided on the inner cylinder 1 of the skeleton;

[0123] Place the fixed insulating end plate 42 into position, attach it to the fixed metal end plate 41, and make contact with the polymer insulating layer;

[0124] The movable metal end plate 43 and the movable insulating end plate 44 are assembled together onto the open end of the inner cylinder 1 of the skeleton to form a winding skeleton.

[0125] The winding frame is installed on the winding machine, and superconducting wire is wound onto the winding frame according to the design to gradually form superconducting coil 2;

[0126] During the winding process, the lead ends and intermediate taps of the superconducting coil 2 are left on one side of the fixed metal end plate 4 of the winding frame; and the lead ends and intermediate taps are tidied up in time, and the wire ends are all inserted into the wire groove 45 of the fixed insulating end plate 42, leaving a sufficient length.

[0127] Remove the winding frame and take off the movable metal end plate 43 and the movable insulating end plate 44;

[0128] Insulating material is wrapped around the superconducting coil 2. At both ends of the superconducting coil 2, a certain length of insulating material is reserved. Specifically, the insulating material on the side closer to the fixed metal end plate 41 is turned outward along the inner plane of the fixed insulating end plate 42, turning up 3-5mm. The insulating material on the side closer to the movable metal end plate 43 is wound cylindrically along the outer surface of the superconducting coil 2, and extends beyond the outer surface of the ring of the superconducting coil 2, leaving a length of 3-5mm to form an insulating material cylinder.

[0129] 3. Assemble the inner side of the outer frame 3;

[0130] The superconducting coil 2, which is wound with insulating material, is connected to the inner cylinder of the skeleton 1, the fixed metal end plate 41, and the fixed insulating end plate 42 as a whole and installed into the outer skeleton 3 from one end.

[0131] During installation, several long fastening screws are pre-inserted into the end plate mounting through hole 46 on the outer ring of the fixed metal end plate 41, and the fastening screws are pre-screwed into the end plate mounting hole 55 of the stainless steel ring 5 at one end of the outer frame 3 to position the installation angle of the fixed metal end plate 41.

[0132] The fixed metal end plate 41 is fixed to the stainless steel ring 5 at one end of the outer frame 3 by fastening screws, and the fastening screws are screwed into the end plate mounting hole 55.

[0133] During installation, the insulating material on the side of the fixed insulating end plate 42 is flipped up by 3-5mm and inserted into the shallow groove 53 of the stainless steel ring 5 on that side.

[0134] During installation, carefully observe the lead end and intermediate tap of the superconducting coil 2, keep them in the wire groove 45 of the fixed insulating end plate 42, and finally leave the ends of the lead end and intermediate tap on the outer ring of the stainless steel ring 5.

[0135] During the installation of the inner cylinder 1 and the superconducting coil 2 inside the outer frame 3, and after installation, epoxy resin is filled in the gap between the outermost insulating material of the superconducting coil 2 and the inner hole of the outer frame 3. Epoxy resin with excellent low-temperature performance is preferred.

[0136] After the inner cylinder 1 and superconducting coil 2 are installed in the outer frame 3, a suitable length of fastening screw is inserted into the end plate mounting through hole 46 of the fixed metal end plate 41. With the help of the anti-loosening locking mechanism (spring washer, thread anti-loosening glue, etc.), the screws are screwed into the end plate mounting hole 55 of the stainless steel ring 5. All fastening screws are tightened with a torque wrench in a symmetrical and uniform stress manner.

[0137] Then, at the opening end of the inner cylinder 1 of the skeleton, the insulating material extending 3 to 5 mm beyond the superconducting coil 2 is turned outward and placed into the shallow groove 53 on that side.

[0138] At the open end of the inner cylinder 1 of the skeleton, cover the previously removed movable metal end plate 43 and movable insulating end plate 44; attach the movable insulating end plate 44 to the superconducting coil 2, and then cover the movable metal end plate 43; adjust the position of the movable metal end plate 43 so that the end plate mounting through hole 46 on it is aligned with the end plate mounting hole 55 of the stainless steel ring 5, then insert the fastening screws of appropriate length, and tighten all the fastening screws as required;

[0139] This involves completing the mechanical assembly of the inner frame 1 and the superconducting coil 2 onto the outer frame 3.

[0140] 4. Welding;

[0141] After the epoxy resin has cured, the movable metal end plate 43 is welded to the inner cylinder 1 of the skeleton by welding.

[0142] Argon arc welding is used for welding. First, multiple points (such as 8 points or 12 points) are selected for intermittent welding around the circumference. Then, two symmetrical welds on the circumference are treated as a group and welded sequentially in a manner that ensures uniform welding stress.

[0143] During welding, the depth and width of the weld pool should not exceed 2mm.

[0144] Thus, the fabrication of the cold mass of the conductive cooling superconducting magnet was completed.

[0145] 5. Assemble the outer structure of the outer frame 3;

[0146] Other components and parts are installed and fixed on the outside of the cold mass of the conductive cooling superconducting magnet;

[0147] Install the accessories of the support leg 6 onto the stainless steel ring 5 of the outer frame 3 in sequence;

[0148] Two highly thermally conductive flexible connectors are assembled onto the outer wall of the outer frame 3, that is, the frame connecting plate 72 is fixed to the outer wall of the outer frame 3, and the outward connecting plate 71 and the flexible connecting plate 73 are arranged.

[0149] Install the relevant electrical connection structure components, such as the coil lead terminal block 74, the intermediate tap terminal block 75, and the quench protection diode assembly 76, onto the stainless steel ring 5 and tighten them with fasteners; finally, connect the lead end and intermediate tap of the superconducting coil 2 to the corresponding electrical connection structure.

[0150] This completes the manufacturing of the conductive cooling superconducting magnet cold mass component of the present invention.

[0151] The conductive cooling superconducting magnet cold mass assembly of the present invention simplifies the manufacturing process, avoids the need to rewind the already wound superconducting coil 2 with high thermal conductivity material, and makes the manufacturing process simpler and more convenient; and with the use of the outer frame 3, together with the stainless steel rings 5 ​​at both ends and the support legs 6, the entire cold mass can be reliably installed into the superconducting magnet, and the support legs 6 arranged in multiple directions can fully bear the force in all directions.

[0152] The conductive cooling superconducting magnet cold mass assembly of the present invention also has the following outstanding advantages:

[0153] 1. The outer frame 3 is made of a high thermal conductivity material and is a thick-walled cylinder. It is used to transfer cold energy, which helps to ensure the temperature uniformity along the entire length of the superconducting coil 2. At the same time, the cold contraction of the high thermal conductivity material from room temperature to operating temperature (less than 4K, -269.15℃) is greater than the cold contraction of the superconducting coil 2 itself. This helps to resist the electromagnetic force of the energized superconducting coil 2 expanding outward in the diameter direction, maintain the state of mutual compression between the superconducting wires, and reduce the number of times the superconducting coil 2 is trained.

[0154] The "training" of superconducting coils: Newly manufactured superconducting magnets often lose quench at currents or magnetic fields much lower than expected. Instead, after multiple cycles of cooling, current increase, and quenching, the superconducting magnet gradually approaches the expected value. This process is figuratively called the "training" of the superconducting coil. Under normal circumstances, a superconducting coil that has completed "training" will not lose quench when operating at currents or magnetic fields below the expected value. Because the "training" process is time-consuming, energy-intensive, and even consumes liquid helium, significantly increasing the manufacturing cost of superconducting devices, the structural design and manufacturing process strive to avoid or minimize the number of training cycles for the superconducting coil.

[0155] 2. The electromagnetic force of the superconducting coil 2 expanding outward in the diameter direction is distributed in the axial direction with a high middle and low two ends. Therefore, although stainless steel rings 5 ​​are used at both ends of the outer frame 3, the amount of cold shrinkage of stainless steel rings 5 ​​is relatively small, thus reducing the amount of cold shrinkage of the entire outer frame assembly at both ends. However, it is still sufficient to resist the electromagnetic force of the superconducting coil 2 expanding outward and maintain the state of mutual compression between the superconducting wires.

[0156] 3. Except for the high thermal conductivity flexible connector, all mechanical connections on the end face and outer surface of the outer frame 3 are fixed to the stainless steel rings 5 ​​at both ends, and no threaded connections are provided on the outer frame 3.

[0157] Compared to high thermal conductivity materials, stainless steel has a much smaller shrinkage from room temperature to operating temperature (less than 4K, -269.15℃). Correspondingly, the stainless steel threaded holes on the stainless steel ring 5 can provide much higher mechanical connection strength than the high thermal conductivity material used in the outer frame 3, making the cold mass structure robust and durable, and completely eliminating the phenomenon of disengagement.

[0158] The outer frame 3 and the stainless steel ring 5 are connected by grooves of different sizes and brazing. The stainless steel rings 5 ​​at both ends can fit around the outer frame 3 from the diameter direction and fix the outer frame 3 from both ends inward along the axis. Thus, a reliable mechanical structure is formed between the outer frame 3 and the superconducting coil 2 and the inner cylinder 1 inside the frame.

[0159] 4. The shallow grooves 53 at both ends of the outer frame 3 increase the creepage distance between it and the superconducting coil 2, ensuring the integrity of the insulation of the superconducting coil 2 to ground.

[0160] 5. The outer skeleton 3 can be prefabricated, which can greatly shorten the manufacturing time of superconducting magnets compared with the winding form of structural reinforcement layer.

[0161] 6. The outer frame assembly, consisting of the outer frame 3 and the stainless steel rings 5 ​​at both ends, integrates all the functions of the cold mass in terms of thermodynamics and structural mechanics; thus simplifying the structure of the cold mass, achieving the final effect of reducing the total mass of the cold mass, and thereby shortening the cooling time of the superconducting equipment.

[0162] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited to the embodiments described. Those skilled in the art can make various equivalent modifications or substitutions without departing from the spirit of the present invention, and these equivalent modifications or substitutions are all included within the scope defined by the claims of this application.

Claims

1. A conductive cooling superconducting magnet cold mass assembly, characterized in that, Along the diameter of the magnetic cavity, it consists of an inner skeleton cylinder, a superconducting coil, and an outer skeleton assembly from the inside out; The inner and outer skeleton components are respectively provided with end plate assemblies at both ends; the inner skeleton, outer skeleton components, and end plate assemblies on both sides form a closed cylindrical cavity, and the superconducting coil is located inside the cylindrical cavity; The outer surface of the inner cylinder of the skeleton is provided with a polymer insulating layer, and the superconducting coil is wound around the polymer insulating layer. The end plate assembly consists of two layers of plates, with the outer layer being a metal end plate and the inner layer being an insulating end plate. The inner ring of the metal end plate is connected and fixed to the inner cylinder of the skeleton, and the outer ring of the metal end plate is connected and fixed to the outer skeleton assembly. The insulating end plate is in contact with the polymer insulating layer to insulate and wrap the superconducting coil. The exoskeleton assembly includes an exoskeleton and stainless steel rings located at both ends of the exoskeleton; The outer frame is made of a highly thermally conductive material; The stainless steel rings are respectively provided at the openings at both ends of the outer frame; The inner wall of the stainless steel ring is connected to the outer wall of the end of the outer frame; the connection between the two is brazed together. The outer frame assembly, consisting of the outer frame and stainless steel rings at both ends, has a straight cylindrical inner side for storing superconducting coils. The superconducting coil is provided with an insulating material layer; the two ends of the outer frame assembly have shallow grooves extending outwards, the two ends of the insulating material layer extend beyond the ends of the superconducting coil, and the portion of the insulating material layer extending beyond the ends of the superconducting coil is folded outwards and stored in the shallow grooves; the insulating end plate covers part or all of the outwardly folded portion of the insulating material located in the shallow grooves. The outer surface of the exoskeleton assembly is provided with several mounting planes, and the mounting planes are provided with mounting screw holes. The outer surface of the outer frame is provided with one or more mounting planes, and a high thermal conductivity flexible connector is mounted on the mounting plane of the outer frame; the high thermal conductivity flexible connector is used to connect the external helium refrigerator and the outer frame; The stainless steel ring has several mounting surfaces, on which legs and electrical connection structural components are mounted. The support has 8 feet, which are located on the stainless steel rings on both sides respectively; the support feet on the stainless steel rings on both sides are arranged inwards relative to each other along the magnetic cavity axis; each stainless steel ring on each side has 4 feet, which are evenly distributed along the magnetic cavity axis. The insulating end plate is provided with a wire passage groove; The center tap and / or lead of the superconducting coil passes through the wire groove on the insulating plate to reach the outer surface of the outer frame assembly, and is then connected to the electrical connection component.

2. The conductive cooling superconducting magnet cold mass assembly as described in claim 1, characterized in that, The outer ring of the metal end plate is provided with mounting holes, and the stainless steel ring is provided with end plate mounting screw holes; the screw passes through the mounting holes on the metal end plate and is screwed into the end plate mounting screw holes on the stainless steel ring to fix the metal end plate to the stainless steel ring. The inner side of the metal end plate is integrally formed or welded to the inner cylinder of the skeleton.

3. The conductive cooling superconducting magnet cold mass assembly as described in claim 1, characterized in that, The inner cavity of the stainless steel ring consists of two straight cylinders, one large and one small, along the axial direction. The small-diameter straight cylinder is located on the outside, and its inner diameter is equal to the inner diameter of the straight cylinder inside the outer skeleton. The large-diameter straight cylinder is located on the inside; The outer frame has circular grooves on both ends; The inner diameter of the large-diameter straight cylinder inside the stainless steel ring is equal to the outer diameter of the circular grooves at both ends of the outer frame. The stainless steel ring is fitted onto the circular grooves at both ends of the outer frame via a large-diameter straight cylindrical sleeve.

4. The conductive cooling superconducting magnet cold mass assembly as described in claim 3, characterized in that, The stainless steel ring is brazed to fix the contact area with the outer frame.

5. The conductive cooling superconducting magnet cold mass assembly as described in claim 3, characterized in that, The wall thickness of the inner cavity of the stainless steel ring, where the small-diameter straight cylindrical part is located, is equal to the wall thickness of the middle skeleton part of the outer skeleton.

6. The conductive cooling superconducting magnet cold mass assembly as described in claim 5, characterized in that, The wall thickness of the inner cavity of the stainless steel ring, where the large-diameter straight cylindrical part is located, is half the wall thickness of the middle skeleton part of the outer skeleton.

7. The conductive cooling superconducting magnet cold mass assembly as described in claim 1, characterized in that, The shallow groove provided on the open end of the stainless steel ring has a width of 3-5 mm and a depth greater than 0.5 mm. A transition chamfer is provided between the shallow groove and the inner wall of the stainless steel ring. The transition chamfer is a circular arc transition with a radius greater than 0.5 mm and less than 1 mm.

8. The conductive cooling superconducting magnet cold mass assembly as described in claim 1, characterized in that, Each support leg includes a support base and a support rod; The support base has a mounting surface, and the mounting surface is provided with a plurality of mounting holes; The stainless steel ring has several corresponding mounting screw holes in the support mounting plane. Stainless steel screws are screwed through the mounting holes on the support base and into the mounting screw holes on the stainless steel ring to fix the support base to the stainless steel ring; The support leg is provided with a support rod seat, and the support rod seat is provided with a support rod hole; One end of the support rod is inserted into the support rod hole and fixed by a threaded connection structure; The support rod is positioned inward along the axis of the magnetic cavity and outward along the diameter of the magnetic cavity; The other end of the support rod is provided with a mounting part for connecting to external equipment.

9. A method for manufacturing a cold mass assembly for a conductive-cooled superconducting magnet: characterized in that, Step 1: Preparation; Prepare the outer frame assembly; install and fix the two stainless steel rings at both ends of the outer frame; Prepare the support legs, highly thermally conductive flexible connectors, and electrical connection structure components; Prepare the skeleton inner cylinder, superconducting wire for the superconducting coil, and end plate components; Step 2, winding; A polymer insulation layer is installed on the inner cylinder of the skeleton; Place the fixed insulating end plate in place, attach it to the fixed metal end plate, and make contact with the polymer insulating layer; The movable metal end plate and the movable insulating end plate are assembled together onto the open end of the inner cylinder of the skeleton to form a winding skeleton. The winding frame is installed on the winding machine, and the superconducting wire is wound onto the winding frame to gradually form a superconducting coil. During the winding process, the middle tap and / or lead end of the superconducting coil are left on one side of the fixed end plate of the winding frame and inserted into the wire groove on the fixed insulating end plate, leaving the end on the outside. After the winding is completed, remove the winding frame with the superconducting coil wound on it; remove the movable metal end plate and the movable insulating end plate; Insulating material is wrapped around the outside of the superconducting coil; and a certain length of insulating material is reserved at both ends of the superconducting coil. That is, the insulating material on the side closer to the fixed insulating end plate is turned up outward along the inner plane of the fixed insulating end plate, turning up 3-5mm; while the insulating material on the side closer to the movable insulating end plate is wound around the outer surface of the superconducting coil in a cylindrical shape, and extends beyond the outer surface of the superconducting coil ring, leaving a length of 3-5mm to form an insulating material cylinder. The outer diameter of the entire superconducting coil assembly after the insulating material is wound is smaller than the inner diameter of the outer frame assembly; Step 3: Assemble the superconducting coil assembly into the outer frame assembly; The superconducting coil, which is wound with insulating material, is connected to the inner cylinder of the skeleton, the fixed metal end plate, and the fixed insulating end plate, and installed from one end of the outer skeleton assembly; The insulating material near the fixed insulating end plate is flipped up 3-5mm and inserted into the shallow groove of the stainless steel ring on that side during the installation process. Leave the center tap and / or the end of the lead wire of the superconducting coil outside the stainless steel ring of the outer frame assembly. During installation, adjust the angle of the fixed metal end plate so that the end plate mounting through hole on the fixed metal end plate is aligned with the end plate mounting hole on the stainless steel ring. After the inner skeleton cylinder and superconducting coil are installed in the outer skeleton assembly, fastening screws are inserted into the end plate mounting through holes of the fixed metal end plate and screwed into the end plate mounting holes of the stainless steel ring to fix the inner skeleton cylinder, superconducting coil, fixed metal end plate, and fixed insulating end plate together onto the stainless steel ring of the outer skeleton assembly. At the open end of the inner cylinder of the skeleton, the insulating material extending 3-5 mm beyond the length reserved for the superconducting coil is turned outward and placed into the shallow groove of the stainless steel ring on that side. At the open end of the inner cylinder of the skeleton, cover the movable metal end plate and movable insulating end plate that were removed in step 2; attach the movable insulating end plate to the superconducting coil cover, and then cover the movable metal end plate; Adjust the position of the movable metal end plate so that its end plate mounting through hole is aligned with the end plate mounting hole of the stainless steel ring. Then, insert the fastening screw into the end plate mounting through hole of the movable metal end plate and screw it into the end plate mounting hole of the stainless steel ring to fix the movable metal end plate and the movable insulating end plate on the stainless steel ring of the outer frame assembly. Step 4: Welding and fixing of the movable metal end plate; The movable metal end plate is connected to the inner cylinder of the skeleton by welding; Argon arc welding is used for welding. First, multiple points are selected for intermittent welding around the circumference. Then, two symmetrical welds on the circumference are grouped together and welded sequentially in a manner that ensures uniform welding stress. During welding, the depth and width of the weld pool should not exceed 2mm; Step 5: Assemble the outer structure of the exoskeleton assembly; Install the leg fittings onto the stainless steel ring of the outer frame assembly in sequence; Assemble the high thermal conductivity flexible connectors onto the outer wall of the outer frame, that is, fix the frame connecting plate to the outer wall of the outer frame, and arrange the outward connecting plate and flexible connecting plate. Install the electrical connection structure onto the stainless steel rings, that is, install the center tap terminal block, and / or coil lead terminal block, and quench protection diode assembly onto the outer wall of the outer frame assembly, and tighten the fasteners onto the stainless steel rings at both ends; connect the center tap and / or lead end of the superconducting coil to the corresponding electrical connection structure.

10. The method for manufacturing the conductive cooling superconducting magnet cold mass assembly as described in claim 9, characterized in that, In step 3 above, during the installation of the superconducting coil assembly within the outer frame assembly, and after installation, epoxy resin is filled into the gap between the outermost insulating material of the superconducting coil and the inner hole of the outer frame assembly.

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