Inner Dewar suitable for frameless superconducting coil

Abstract

The invention relates to the technical field of ultrahigh-speed magnetic suspension, and discloses an inner Dewar suitable for a frameless superconducting coil, which comprises a straight edge section inner Dewar, a circular arc section inner Dewar, a straight edge section pre-tightening fixing piece, a circular arc section pre-tightening fixing piece, a first reinforcing piece, a second reinforcing piece and a connecting sealing welding seam, the straight section inner Dewar wraps the straight section of the runway type superconducting coil and stores a refrigerating medium, the arc section inner Dewar wraps the arc section of the runway type superconducting coil and stores a refrigerating medium, and straight section pre-tightening fixing pieces are arranged on the straight section inner Dewar and at the joint of the straight section inner Dewar and the arc section inner Dewar. An arc section pre-tightening fixing piece is arranged on the arc section inner Dewar, the first reinforcing piece is arranged between the upper straight edge section and the lower straight edge section of the runway type superconducting coil, and the second reinforcing piece is arranged on the first reinforcing piece. And the connecting sealing welding seam is used for connecting the runway type superconducting coil, the straight-edge-section inner Dewar, the arc-section inner Dewar, the straight-edge-section pre-tightening fixing piece and the arc-section pre-tightening fixing piece into an integral structure.

Description

Technical Field

[0001] This invention relates to the field of ultra-high-speed magnetic levitation technology, and in particular to an inner Dewar suitable for frameless superconducting coils. Background Technology

[0002] The cryogenic superconducting magnet for ultra-high-speed magnetic levitation is a core component of the levitation and propulsion systems of electric maglev trains and ultra-high-speed vacuum tube maglev trains. The cryogenic superconducting magnet enters and maintains a superconducting state at an extremely low temperature of 4.2K. A large current is supplied to the cryogenic superconducting coil through an external excitation device. The cryogenic superconducting coil provides a high-strength and stable magnetic field for the motor system and levitation system in a closed-loop constant current state.

[0003] Frameless superconducting coils represent a crucial technological approach for lightweight superconducting magnet design. Correspondingly, the inner Dewar for frameless superconducting coils must enclose the coil and store liquid nitrogen and liquid helium used during coil pre-cooling and refrigeration. On one hand, the inner Dewar of the frameless superconducting coil needs to maintain an extremely low temperature environment during coil operation. On the other hand, the electromagnetic load generated by the superconducting coil is transferred to the frameless inner Dewar via clamps, and further transferred to the outside through the inner Dewar to generate levitation, guidance, and propulsion forces.

[0004] Conventional superconducting magnets are mostly based on a coil with a frame, such as a ring-shaped frame or a D-shaped frame. The inner Dewar structure matches the shape of the frame and is designed to be ring-shaped or D-shaped. The frame is equipped with a connecting weld interface, which is sealed and welded to the inner Dewar to form a whole, enclosing the superconducting coil and storing liquid helium.

[0005] The cryogenic superconducting magnet coils used in ultra-high-speed magnetic levitation are racetrack-shaped, which differs significantly from the structure of conventional superconducting magnet coils. Therefore, the superconducting coil skeleton for magnetic levitation is designed in a racetrack shape, with welded interfaces for connection to the inner Dewar. The skeleton and inner Dewar are sealed and welded together to form a single unit for cryogenic dielectric storage and load transfer of the superconducting coil. However, on the one hand, the inner Dewar of conventional superconducting magnet coils differs greatly from that of superconducting coils for magnetic levitation in terms of structure, load environment, and electromagnetic force transmission; on the other hand, the presence of the skeleton in the racetrack-shaped superconducting coil increases the mass and volume of the superconducting coil unit, thereby increasing the overall volume and weight of the superconducting magnet, which is detrimental to the requirements of compact and lightweight structure of magnetic levitation superconducting magnets. Therefore, developing a skeletonless superconducting coil and its matching inner Dewar design is an important way to solve the problem of lightweighting of superconducting magnets for magnetic levitation. Summary of the Invention

[0006] This invention provides an inner Dewar suitable for frameless superconducting coils, which can solve the technical problems in the prior art.

[0007] This invention provides an inner Dewar suitable for frameless superconducting coils. The inner Dewar includes a straight-edge section inner Dewar, an arc-shaped section inner Dewar, a straight-edge section pre-tightening fastener, an arc-shaped section pre-tightening fastener, a first reinforcing member, a second reinforcing member, and a connecting sealing weld. The straight-edge section inner Dewar is used to wrap the straight-edge section of the racetrack-shaped superconducting coil and store the cooling medium. The arc-shaped section inner Dewar is used to wrap the arc-shaped section of the racetrack-shaped superconducting coil and store the cooling medium. The straight-edge section inner Dewar and the inner Dewar connecting to the arc-shaped superconducting coil are also designed to store the cooling medium. The straight-edge pre-tightening fastener is provided at the Dewar connection of the arc segment, and the arc segment pre-tightening fastener is provided on the Dewar of the arc segment. The first reinforcing member is provided between the upper and lower straight-edge segments of the racetrack-shaped superconducting coil, and the second reinforcing member is provided on the first reinforcing member. The connecting sealing weld is used to connect the racetrack-shaped superconducting coil, the straight-edge segment Dewar, the arc segment Dewar, the straight-edge segment pre-tightening fastener, and the arc segment pre-tightening fastener into an integral structure.

[0008] Preferably, the straight-edge pre-tightening fastener and the arc-shaped pre-tightening fastener are clamps.

[0009] Preferably, the straight-edge pre-tightening fastener and the arc-shaped pre-tightening fastener are installed using assembly tools or bolts.

[0010] Preferably, the first reinforcing member is disposed between the upper and lower straight sides of the racetrack-shaped superconducting coil by welding, and the second reinforcing member is disposed on the first reinforcing member by welding.

[0011] Preferably, the first reinforcing member is a reinforcing plate.

[0012] Preferably, the second reinforcing member is a reinforcing ring, and the reinforcing plate is provided with a through hole, and the reinforcing ring is welded into the through hole.

[0013] Preferably, the reinforcing ring is provided with a threaded interface as an interface for transmitting normal loads.

[0014] Preferably, an oxygen-free copper gasket is provided between the straight-edge pre-tightening fastener and the inner Dewar of the straight-edge section and the inner Dewar of the arc section.

[0015] Preferably, the materials of the inner Dewar in the straight-edge section, the inner Dewar in the arc section, the pre-tightening fastener in the straight-edge section, and the pre-tightening fastener in the arc section are non-magnetic stainless steel.

[0016] Preferably, the racetrack-shaped superconducting coil is wound using either dry or wet winding methods.

[0017] The above technical solutions can solve problems such as liquid helium storage, immersion cooling and lightweight coil design for low-temperature superconducting coils used in magnetic levitation, ensuring the temperature stability of the low-temperature superconducting coil while achieving a lightweight design of the frameless superconducting coil, thereby improving the load-bearing capacity of the levitation system and the propulsion efficiency of the motor. Attached Figure Description

[0018] The accompanying drawings, which form part of this specification, are provided to further illustrate embodiments of the invention and, together with the textual description, explain the principles of the invention. It is obvious that the drawings described below are merely some embodiments of the invention, and those skilled in the art can obtain other drawings based on these drawings without any creative effort.

[0019] Figure 1 A three-dimensional schematic diagram of an inner Dewar suitable for a frameless superconducting coil according to an embodiment of the present invention is shown;

[0020] Figure 2 A front view of an inner Dewar suitable for a frameless superconducting coil according to an embodiment of the present invention is shown. Detailed Implementation

[0021] It should be noted that, unless otherwise specified, the embodiments and features described in this application can be combined with each other. 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 a part of the embodiments of the present invention, and not all of them. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. 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.

[0022] It should be noted that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to limit the exemplary embodiments according to this application. As used herein, the singular form is intended to include the plural form as well, unless the context clearly indicates otherwise. Furthermore, it should be understood that when the terms "comprising" and / or "including" are used in this specification, they indicate the presence of features, steps, operations, devices, components, and / or combinations thereof.

[0023] Unless otherwise specifically stated, the relative arrangement, numerical expressions, and values ​​of the components and steps set forth in these embodiments do not limit the scope of the invention. It should also be understood that, for ease of description, the dimensions of the various parts shown in the drawings are not drawn to actual scale. Techniques, methods, and devices known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques, methods, and devices should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values. It should be noted that similar reference numerals and letters in the following figures denote similar items; therefore, once an item is defined in one figure, it need not be further discussed in subsequent figures.

[0024] like Figure 1 and 2 As shown, this embodiment of the invention provides an inner Dewar suitable for frameless superconducting coils. The inner Dewar includes a straight-edge section inner Dewar 3, an arc-shaped section inner Dewar 4, a straight-edge section pre-tightening fastener 2, an arc-shaped section pre-tightening fastener 5, a first reinforcing member 6, a second reinforcing member 7, and a connecting sealing weld (racetrack type) 8. The straight-edge section inner Dewar 3 is used to wrap the straight-edge section of the racetrack-shaped superconducting coil 1 and store the cooling medium. The arc-shaped section inner Dewar 4 is used to wrap the arc-shaped section of the racetrack-shaped superconducting coil 1 and store the cooling medium. The straight-edge section inner Dewar 3 and the straight-edge section... The straight-edge pre-tightening fastener 2 is provided at the connection between the inner Dewar 3 and the arc-shaped inner Dewar 4. The arc-shaped inner Dewar 4 is provided with the arc-shaped pre-tightening fastener 5. The first reinforcing member 6 is provided between the upper and lower straight-edge sections of the runway-shaped superconducting coil 1. The second reinforcing member 7 is provided on the first reinforcing member 6. The connecting sealing weld 8 is used to connect the runway-shaped superconducting coil 1, the straight-edge inner Dewar 3, the arc-shaped inner Dewar 4, the straight-edge pre-tightening fastener 2, and the arc-shaped pre-tightening fastener 5 into an integral structure.

[0025] The first reinforcing member supports the upper and lower straight edges of the superconducting coil and resists its deformation under stress; the second reinforcing member 7 is integrally formed on the first reinforcing member 6. By welding and sealing the weld seam 8, the inner Dewar wraps around the superconducting coil and is firmly connected to the pre-tightening fixing member, forming a frameless superconducting coil unit.

[0026] The above technical solutions can solve problems such as liquid helium storage, immersion cooling and lightweight coil design for low-temperature superconducting coils used in magnetic levitation, ensuring the temperature stability of the low-temperature superconducting coil while achieving a lightweight design of the frameless superconducting coil, thereby improving the load-bearing capacity of the levitation system and the propulsion efficiency of the motor.

[0027] According to one embodiment of the present invention, the straight-edge pre-tightening fastener 2 and the arc-shaped pre-tightening fastener 5 are clamps.

[0028] The straight-edge section inner Dewar 3 and the arc section inner Dewar 4 are installed on the outer periphery of the superconducting coil 1. The clamps of the straight-edge section and the arc section can be integrated with the straight-edge section inner Dewar 3 and the arc section inner Dewar 4 by means of assembly tooling and clamping.

[0029] Therefore, the straight edge section of the superconducting coil can be preloaded by the clamps on the straight edge section in a circumferential manner to fix the straight edge section of the superconducting coil; the arc section of the superconducting coil can be preloaded by the clamps on the arc section to fix the arc section of the superconducting coil.

[0030] According to one embodiment of the present invention, the straight edge pre-tightening fastener 2 and the arc segment pre-tightening fastener 5 are installed by assembly fixtures or bolts.

[0031] That is, by means of assembly tooling or bolt tightening, the straight edge pre-tightening fastener 2 and the arc segment pre-tightening fastener 5 are installed on the straight edge and arc segment of the superconducting coil, so as to provide pre-tightening force for the entire runway-shaped perimeter of the superconducting coil 1 and fix it firmly.

[0032] According to one embodiment of the present invention, the first reinforcing member 6 is disposed between the upper straight side section and the lower straight side section of the runway-shaped superconducting coil 1 by welding, and the second reinforcing member 7 is disposed on the first reinforcing member 6 by welding.

[0033] According to one embodiment of the present invention, the first reinforcing member 6 is a reinforcing plate.

[0034] Reinforcing plates are installed on the upper and lower sides of the straight edge section of the superconducting coil to support the upper and lower parts of the coil, which can improve the deformation resistance of the straight edge section. Furthermore, support plates (reinforcing plates) can also be added to the arc section of the superconducting coil to improve the deformation resistance of the arc section. The support plates are connected to the inner Dewar or clamp by welding.

[0035] According to one embodiment of the present invention, the second reinforcing member 7 is a reinforcing ring, and the reinforcing plate is provided with a through hole, and the reinforcing ring is welded into the through hole.

[0036] According to one embodiment of the present invention, the reinforcing ring is provided with a threaded interface as an interface for transmitting normal loads.

[0037] In other words, the frameless superconducting coil and its integrated inner Dewar support points can adopt a 4-point, 6-point, or 8-point support method with four corner lugs. The support ring is firmly connected to the support plate by welding. Threaded connection holes can be set on the support ring as an interface for normal load transmission.

[0038] For example, a reinforcing plate can be welded to the inner Dewar, connecting the upper and lower straight edges of the superconducting coil to support it. A reinforcing ring is welded to the reinforcing plate, transmitting the electromagnetic load generated by the superconducting coil through round holes and threaded holes.

[0039] According to one embodiment of the present invention, an oxygen-free copper gasket is provided between the straight edge pre-tightening fastener 2 and the straight edge inner Dewar 3 and the arc-shaped inner Dewar 4.

[0040] According to one embodiment of the present invention, the materials of the straight-edge section inner Dewar 3, the arc section inner Dewar 4, the straight-edge section pre-tightening fastener 2, and the arc section pre-tightening fastener 5 are non-magnetic stainless steel.

[0041] Specifically, the clamps on the straight-edge section and the clamps on the arc section can be made of non-magnetic stainless steel, such as stainless steel 304, 304L, 304LN / 316 / 316L / 316LN, etc., in a split-half structure, with a preferred top-to-bottom split configuration. The clamps on the straight-edge section can apply a tightening force to the superconducting coil through external assembly fixtures or bolt connections on the clamps. Furthermore, oxygen-free copper gaskets can be added between the clamps on the straight-edge section and the superconducting coil (corresponding to the inner Dewar 3 on the straight-edge section and the inner Dewar 4 on the arc section) to improve thermal conductivity and reduce frictional heat. The inner Dewars on the straight-edge section and the inner Dewars on the arc section can be made of non-magnetic stainless steel, such as stainless steel 304, 304L, 304LN / 316 / 316L / 316LN, etc., in a split-half structure, and can be formed by bending sheet metal or integral machining. A locking bottom structure can be provided on the inner edge of the inner Dewar to improve the assembly accuracy between the inner Dewar and the clamp.

[0042] According to one embodiment of the present invention, the racetrack-shaped superconducting coil 1 is wound using dry winding or wet winding methods.

[0043] Furthermore, the surface of the formed coil can be further wrapped with kapton, glass fiber cloth tape, etc. for insulation, vibration reduction, and wear resistance treatment.

[0044] In this invention, the split straight edge and arc segment inner Dewar, and the split straight edge and arc segment clamp can be connected into a whole by sealing welding. The welding method can be vacuum electron beam welding or argon arc welding.

[0045] The present invention also provides a superconducting magnet, including the inner Dewar described in the above embodiments for use with frameless superconducting coils. This superconducting magnet can be applied in the field of ultra-high-speed magnetic levitation.

[0046] As can be seen from the above embodiments, the inner Dewar of the present invention, suitable for frameless superconducting coils, has at least the following advantages:

[0047] 1) Frameless superconducting coils can be dry-wound or wet-wound, with low requirements for winding processability, good winding processability, and strong operability;

[0048] 2) The frameless superconducting coil and its integrated inner Dewar eliminate the frame, improve the structural compactness of the superconducting coil unit, reduce the mass and volume of the superconducting coil unit, and thus help to reduce the lightweight design of superconducting magnets;

[0049] 3) Frameless superconducting coils and their integrated inner Dewars can achieve refined design of superconducting coils by optimizing the number and arrangement of clamps to constrain and control the local deformation of the superconducting coils;

[0050] 4) The frameless superconducting coil and its integrated inner Dewar increase the contact area between the superconducting coil and the cooling medium, making the superconducting coil cool more uniformly, with higher heat exchange efficiency and better thermal stability.

[0051] 5) The integrated internal Dewar structure can be sealed and connected by vacuum electron beam or argon arc welding, with high weld strength, low leakage rate and good manufacturability.

[0052] In general, the frameless superconducting coil and its integrated inner Dewar have the functions of liquid helium storage, pressure bearing, load bearing and support of the superconducting coil, while the frameless superconducting coil and its inner Dewar have reduced the outer dimensions of the superconducting coil by omitting the frame structure, making the superconducting coil unit structure more compact and lighter.

[0053] In the description of this invention, it should be understood that the orientation or positional relationship indicated by directional terms such as "front, back, up, down, left, right", "horizontal, vertical, horizontal" and "top, bottom" is generally based on the orientation or positional relationship shown in the accompanying drawings, and is only for the convenience of describing this invention and simplifying the description. Unless otherwise stated, these directional terms do not indicate or imply that the device or element referred to must have a specific orientation or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on the scope of protection of this invention; the directional terms "inner" and "outer" refer to the inner and outer contours relative to the outline of each component itself.

[0054] For ease of description, spatial relative terms such as "above," "on top of," "on the upper surface of," "above," etc., are used herein to describe the spatial positional relationship of a device or feature as shown in the figures to other devices or features. It should be understood that spatial relative terms are intended to encompass different orientations in use or operation beyond the orientation of the device as described in the figures. For example, if the device in the figures were inverted, a device described as "above" or "on top of" other devices or structures would subsequently be positioned as "below" or "under" other devices or structures. Thus, the exemplary term "above" can include both "above" and "below." The device may also be positioned in other different ways (rotated 90 degrees or in other orientations), and the spatial relative descriptions used herein will be interpreted accordingly.

[0055] Furthermore, it should be noted that the use of terms such as "first" and "second" to define components is merely for the purpose of distinguishing the corresponding components. Unless otherwise stated, the above terms have no special meaning and therefore should not be construed as limiting the scope of protection of this invention.

[0056] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. An inner Dewar suitable for frameless superconducting coils, characterized in that, The inner Dewar includes a straight-edge section inner Dewar (3), an arc-shaped section inner Dewar (4), a straight-edge section pre-tightening fastener (2), an arc-shaped section pre-tightening fastener (5), a first reinforcing member (6), a second reinforcing member (7), and a connecting sealing weld (8). The straight-edge section inner Dewar (3) is used to wrap the straight-edge section of the runway-shaped superconducting coil (1) and store the cooling medium. The arc-shaped section inner Dewar (4) is used to wrap the arc-shaped superconducting coil (1) and store the cooling medium. The straight-edge section inner Dewar (3) and the connection between the straight-edge section inner Dewar (3) and the arc-shaped section inner Dewar (4) are also included. The straight-side pre-tightening fastener (2) is provided, and the arc-shaped segment pre-tightening fastener (5) is provided on the arc-shaped segment inner Dewar (4). The first reinforcing member (6) is provided between the upper and lower straight-side segments of the runway-shaped superconducting coil (1). The second reinforcing member (7) is provided on the first reinforcing member (6). The connecting sealing weld (8) is used to connect the runway-shaped superconducting coil (1), the straight-side segment inner Dewar (3), the arc-shaped segment inner Dewar (4), the straight-side pre-tightening fastener (2), and the arc-shaped segment pre-tightening fastener (5) into an integral structure.

2. The inner Dewar for frameless superconducting coils according to claim 1, characterized in that, The straight-edge pre-tightening fastener (2) and the arc-shaped pre-tightening fastener (5) are clamps.

3. The inner Dewar for frameless superconducting coils according to claim 2, characterized in that, The straight-edge pre-tightening fastener (2) and the arc-shaped pre-tightening fastener (5) are installed by assembly tools or bolts.

4. The inner Dewar for frameless superconducting coils according to claim 2, characterized in that, The first reinforcing member (6) is disposed between the upper straight side and the lower straight side of the runway-shaped superconducting coil (1) by welding, and the second reinforcing member (7) is disposed on the first reinforcing member (6) by welding.

5. The inner Dewar for frameless superconducting coils according to claim 4, characterized in that, The first reinforcing member (6) is a reinforcing plate.

6. The inner Dewar for frameless superconducting coils according to claim 5, characterized in that, The second reinforcing member (7) is a reinforcing ring. The reinforcing plate is provided with a through hole, and the reinforcing ring is welded into the through hole.

7. The inner Dewar for frameless superconducting coils according to claim 6, characterized in that, The reinforcing ring is provided with a threaded interface, which serves as the interface for transmitting normal loads.

8. The inner Dewar for frameless superconducting coils according to claim 7, characterized in that, An oxygen-free copper gasket is provided between the straight-edge pre-tightening fastener (2) and the straight-edge inner Dewar (3) and the arc-shaped inner Dewar (4).

9. The inner Dewar for frameless superconducting coils according to any one of claims 1-8, characterized in that, The materials of the straight-edge section inner Dewar (3), the arc section inner Dewar (4), the straight-edge section pre-tightening fastener (2), and the arc section pre-tightening fastener (5) are non-magnetic stainless steel.

10. The inner Dewar for frameless superconducting coils according to any one of claims 1-8, characterized in that, The racetrack-shaped superconducting coil (1) is wound using dry or wet winding methods.

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