Superconducting magnet and magnetic resonance imaging equipment

Abstract

The utility model provides a superconducting magnet which comprises a superconducting wire (10) and an interlayer heat conduction structure (20). The superconducting wire (10) is wound in a ring shape and is used for forming a main magnetic field of the magnetic resonance imaging device. The superconducting wire (10) has a plurality of conductor layers (11) distributed in the radial direction (R). The interlayer heat conduction structure (20) is arranged between two adjacent lead layers (11) along the radial direction (R). The interlayer heat conduction structure (20) is used for being connected with a cold source in a heat conduction mode. The superconducting magnet is beneficial to reducing the radial temperature difference of the superconducting wire in the cooling process.

Description

Technical Field

[0001] The utility model relates to the field of magnetic resonance imaging, in particular to a superconducting magnet and a magnetic resonance imaging device comprising the same. Background Art

[0002] In existing magnetic resonance imaging equipment, the superconducting wire wound into a ring in the superconducting coil is used to generate the main magnetic field for imaging. The superconducting coil is immersed in low-temperature liquid helium with a small latent heat of vaporization, and the liquid helium is kept in a liquefied form by a refrigerator, so that the superconducting wire can remain in a superconducting state.

[0003] However, liquid helium is expensive and needs to be replenished regularly, so a dry superconducting magnet that does not require the superconducting coil to be immersed in a large amount of low-temperature liquid helium has been proposed. When cooling a dry superconducting magnet, a refrigerator is required to slowly cool the superconducting wire to the superconducting operating temperature through a cooling structure. The cooling structure currently used is to input cold energy from the radial outside of the entire superconducting wire.

[0004] The thermal conductivity of the superconducting wire in the circumferential direction (along the length of the wire) is 2 to 3 orders of magnitude higher than that in the radial direction (along the wire layer), which makes its circumferential cooling rate faster than its radial cooling rate. Using the existing cooling structure, the cooling rate of the superconducting wire will be limited by its radial thermal conductivity, especially when the thickness of the superconducting wire in the radial direction is very thick, which will lead to a large radial temperature difference of the superconducting wire during the cooling process. This may cause relatively large thermal stress inside the coil and ultimately have an adverse effect on product performance. Utility Model Content

[0005] The utility model aims to provide a superconducting magnet, which is beneficial to reducing the radial temperature difference of a superconducting wire during a cooling process.

[0006] Another object of the utility model is to provide a magnetic resonance imaging device, which is beneficial to reducing the radial temperature difference of the superconducting wire during the cooling process.

[0007] The utility model provides a superconducting magnet, which comprises a superconducting wire and an interlayer heat-conducting structure. The superconducting wire is wound into a ring shape and is used to form a main magnetic field of a magnetic resonance imaging device. The superconducting wire has a plurality of wire layers distributed in a radial direction. The interlayer heat-conducting structure is arranged between two wire layers adjacent in a radial direction. The interlayer heat-conducting structure is used to connect a cold source in a heat-conducting manner.

[0008] The conductor layer of the superconducting magnet can obtain cold energy from a cold source through the interlayer heat-conducting structure adjacent thereto, thereby facilitating the reduction of the radial temperature difference of the superconducting wire during the cooling process.

[0009] In another exemplary embodiment of the superconducting magnet, the interlayer heat-conducting structure is a metal mesh or a metal foil, which is relatively soft and convenient to lay.

[0010] In another exemplary embodiment of the superconducting magnet, the interlayer heat-conducting structure is in the shape of a ring extending in the circumferential direction, thereby facilitating the reduction of the circumferential temperature difference of the superconducting wire during the cooling process.

[0011] In another exemplary embodiment of the superconducting magnet, the superconducting wire includes more than three wire layers, and an interlayer heat conduction structure is provided between each wire layer and one or two adjacent wire layers, thereby facilitating uniform cooling of the superconducting wire.

[0012] In another exemplary embodiment of the superconducting magnet, the superconducting magnet includes several superconducting wires distributed in the axial direction. The superconducting magnet also includes a heat transfer unit. The heat transfer unit includes a main heat conductor and a branch heat conductor. The main heat conductor is arranged radially outside the several superconducting wires and at least a portion thereof extends in the axial direction of the superconducting magnet. The main heat conductor is used to be heat-conductively connected to a cold source. One end of each branch heat conductor is heat-conductively connected to the main heat conductor, and the other end extends into the axial interval of two adjacent superconducting wires and is heat-conductively connected to an interlayer heat-conductive structure arranged in one or both of the superconducting wires. This can make the overall structure more compact.

[0013] In another exemplary embodiment of the superconducting magnet, the main heat conductor includes one or a combination of metal plates, metal braids, refrigerant circuits and heat pipes; and / or the branch heat conductor includes one or a combination of metal plates, metal braids, refrigerant circuits and heat pipes, thereby improving the heat conduction efficiency.

[0014] In another exemplary embodiment of the superconducting magnet, each superconducting wire and the interlayer heat-conducting structure disposed between the wire layers are embedded by an embedding body to form a ring-shaped superconducting coil, thereby facilitating the improvement of stability.

[0015] In another exemplary embodiment of the superconducting magnet, the superconducting magnet further includes a spacer. The spacer is in a ring shape extending in the circumferential direction and is fixed between two adjacent superconducting coils. The spacer and the embedding body are formed by one-time injection molding. One end of the branch heat conductor for connecting the interlayer heat conductive structure is embedded in the spacer. This helps to improve the stability of the structure.

[0016] The utility model also provides a magnetic resonance imaging device, which includes the above-mentioned superconducting magnet and a cold source. The interlayer heat-conducting structure can be connected to the cold source in a heat-conducting manner. The conductor layer of the superconducting magnet can obtain cold energy from the cold source through the interlayer heat-conducting structure adjacent to it, thereby facilitating the reduction of the radial temperature difference of the superconducting wire during the cooling process.

[0017] In another exemplary embodiment of the magnetic resonance imaging device, the cold source is a refrigerator. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The following drawings are only used to illustrate and explain the present invention, and do not limit the scope of the present invention.

[0019] Figure 1 A schematic structural diagram of an exemplary embodiment of a superconducting magnet.

[0020] Figure 2 for Figure 1 Schematic diagram of the structure of the superconducting wire of the superconducting magnet shown.

[0021] Figure 3 Used to illustrate the position of the interlayer heat conduction structure in the superconducting wire.

[0022] Figure 4 Used to illustrate the annular interlayer heat conduction structure.

[0023] Figure 5 For illustration Figure 1 The superconducting magnet shown.

[0024] Figure 6 Another exemplary embodiment for illustrating a superconducting magnet.

[0025] Description of symbols

[0026] 10Superconducting wire

[0027] 11 wire layers

[0028] 12 Conductor cross section

[0029] 20-layer heat conduction structure

[0030] 30 heat transfer units

[0031] 31 Main heating element

[0032] 32 branch heat conductor

[0033] 40 Embedded body

[0034] 50 superconducting coils

[0035] 60 spacer

[0036] 70 bracket

[0037] 100 Superconducting Magnets

[0038] 200 cold source

[0039] R Radial

[0040] T Circumferential

[0041] A-axis DETAILED DESCRIPTION

[0042] In order to have a clearer understanding of the technical features, purposes and effects of the utility model, the specific implementation methods of the utility model are now described with reference to the accompanying drawings. The same reference numerals in the drawings represent components with the same structure or similar structures but the same functions.

[0043] In this document, “exemplary” means “serving as an example, instance or illustration”, and any diagram or implementation described in this document as “exemplary” should not be interpreted as a more preferred or more advantageous technical solution.

[0044] In order to make the drawings concise, each figure only schematically shows the parts related to the utility model, which do not represent the actual structure of the product.

[0045] Figure 1 FIG. 1 is a schematic diagram of a superconducting magnet according to an exemplary embodiment. Figure 1 As shown, the superconducting magnet 100 includes a plurality of superconducting coils 50 arranged along the axial direction A (i.e., the main magnetic field direction). In this exemplary embodiment, the superconducting magnet 100 includes three superconducting coils 50 as an example for illustration, but is not limited thereto. In other exemplary embodiments, the number of superconducting coils 50 in the superconducting magnet 100 can be adjusted as needed.

[0046] Each superconducting coil 50 includes a superconducting wire wound into a ring shape. Figure 2 3 shows three superconducting wires 10 distributed along the axial direction A of three superconducting coils 50. The superconducting wires 10 are used to form a main magnetic field of a magnetic resonance imaging apparatus. Figure 3 1 shows an axial cross section of a superconducting wire 10, wherein each small rectangular block in the figure represents a wire cross section 12 of the superconducting wire 10. Figure 3 As shown, the superconducting wire 10 has a plurality of conductor layers 11 distributed along a radial direction R, wherein the radial direction R is perpendicular to the axial direction A. Figure 3 The frame drawn with dot-dash lines in the figure encircles the conductor layer 11 located at the uppermost layer.

[0047] Each superconducting coil 50 also includes an interlayer heat conduction structure. Figure 3 As shown, the interlayer heat-conducting structure 20 is disposed between two adjacent wire layers 11 along the radial direction R. Figure 3 The interlayer heat-conducting structure 20 is indicated by a dotted line. The interlayer heat-conducting structure 20 is used to connect the cold source in a heat-conducting manner. The cold source refers to a device that can output cold energy, such as a refrigerator, and the refrigerator is, for example, a GM refrigerator, but is not limited thereto.

[0048] During the cooling process of the superconducting wire, the interlayer heat-conducting structure 20 first obtains cold energy from the cold source, and then transfers the cold energy to the conductor layers 11 on both sides thereof. The conductor layer 11 can obtain cold energy from the cold source through the interlayer heat-conducting structure 20 adjacent thereto, thereby facilitating the reduction of the radial temperature difference of the superconducting wire during the cooling process.

[0049] In an exemplary embodiment, the interlayer heat-conducting structure 20 is a metal mesh or metal foil, which is relatively soft and convenient to lay. The metal is, for example, copper or aluminum to obtain good thermal conductivity.

[0050] In the exemplary embodiment, the interlayer heat conductive structure 20 is in a ring shape extending along the circumferential direction T. Figure 4 The diagram schematically shows a ring-shaped interlayer heat conducting structure 20 ( Figure 4 The interlayer heat-conducting structure 20 is indicated by a dotted line in the figure). This helps to reduce the circumferential temperature difference of the superconducting wire during the cooling process. However, it is not limited thereto. In other exemplary embodiments, the laying range of the interlayer heat-conducting structure 20 can be adjusted as needed.

[0051] like Figure 3 As shown, in this exemplary embodiment, the number of conductor layers 11 of the superconducting wire 10 exceeds two. An interlayer heat-conducting structure 20 is provided between each conductor layer 11 and an adjacent conductor layer 11. In this way, each conductor layer 11 can obtain cooling from the interlayer heat-conducting structure 20 adjacent thereto. This facilitates uniform cooling of the superconducting wire. However, it is not limited thereto. In other exemplary embodiments, an interlayer heat-conducting structure 20 may be provided between each conductor layer 11 and two adjacent conductor layers 11. Of course, the number and position of the interlayer heat-conducting structure 20 may also be set as required to further reduce the radial temperature difference of the superconducting wire during the cooling process.

[0052] like Figure 1 As shown, in the exemplary embodiment, the superconducting magnet further includes a heat transfer unit 30 . Figure 5 The axial section of the heat transfer unit 30 and the rest of the superconducting magnet is shown. Figure 1 and Figure 5 As shown, the heat transfer unit 30 includes a main heat conductor 31 and three branch heat conductors 32. The main heat conductor 31 is arranged outside the radial direction R of several superconducting wires 10 and its left end extends along the axial direction A of the superconducting magnet. The right end of the main heat conductor 31 is used to be thermally connected to the cold source 200. One end of each branch heat conductor 32 is thermally connected to the main heat conductor 31, and the other end extends into the axial interval of two adjacent superconducting wires 10 and is thermally connected to the interlayer heat conductive structure 20 provided in one of the superconducting wires 10. In order to connect multiple interlayer heat conductive structures 20, one end of the branch heat conductor 32 used for connecting the interlayer heat conductive structure 20 is, for example, branched. This can make the overall structure more compact. In other exemplary embodiments, the other end of each branch heat conductor 32 can also extend into the axial interval of two adjacent superconducting wires 10 and be thermally connected to the interlayer heat conductive structure 20 provided in these two superconducting wires 10.

[0053] In other exemplary embodiments, the superconducting magnet may also be provided with a plurality of heat transfer units 30 , which are, for example, arranged around the superconducting wire 10 along a circumferential direction T perpendicular to the axial direction A. The same interlayer heat conductive structure 20 may be connected to a heat sink via a plurality of heat transfer units 30 .

[0054] In this exemplary embodiment, the main heat conductor 31 is, for example, a metal plate, and the branch heat conductor 32 is, for example, a metal braid, but is not limited thereto. In other exemplary embodiments, the main heat conductor 31 may include, for example, a metal plate, a metal braid, a refrigerant circuit, and a heat pipe, or a combination thereof, and the branch heat conductor 32 may include, for example, a metal plate, a metal braid, a refrigerant circuit, and a heat pipe, or a combination thereof. These structures all have good thermal conductivity. This helps to improve the efficiency of heat conduction. The metal, for example, copper or aluminum is selected to obtain a higher thermal conductivity.

[0055] like Figure 5 As shown, in the exemplary embodiment, each superconducting wire 10 and the interlayer heat conductive structure 20 disposed between the wire layers 11 thereof are embedded by an embedding body 40 to form a superconducting coil 50. The embedding body 40 is, for example, a thermoplastic resin, but is not limited thereto. In this way, the superconducting wire and the interlayer heat conductive structure can be fixed, thereby facilitating improved stability.

[0056] like Figure 1 and Figure 5 As shown, in the exemplary embodiment, the superconducting magnet further includes two spacers 60. The spacer 60 is annular and extends along the circumferential direction T and is fixed between two adjacent superconducting coils 50. The spacer 60 and the embedding body 40 are formed by one-time casting. One end of the branch heat conductor 32 for connecting the interlayer heat conductive structure 20 is embedded in the spacer 60. This helps to improve the stability of the structure, but is not limited to this. Figure 6 Another exemplary embodiment for illustrating a superconducting magnet. Figure 6 In the exemplary embodiment shown, the spacer 60 is not provided, but three superconducting coils 50 are fixed to one bracket 70 .

[0057] The utility model also provides a magnetic resonance imaging device, in one exemplary embodiment of which the magnetic resonance imaging device comprises Figure 1 The superconducting magnet 100 and the cold source are shown. Figure 5 As shown, the interlayer heat conductive structure 20 can be heat conductively connected to the cold source 200 through the heat transfer unit 30. The cold source 200 is, for example, a refrigerator. The refrigerator is, for example, a GM refrigerator, but is not limited thereto. During the cooling process of the superconducting wire, the interlayer heat conductive structure 20 first obtains cold energy from the cold source, and then transfers the cold energy to the wire layers 11 on both sides thereof. The wire layer 11 can obtain cold energy from the cold source through the interlayer heat conductive structure 20 adjacent thereto, thereby facilitating the reduction of the radial temperature difference of the superconducting wire during the cooling process.

[0058] It should be understood that although this specification is described according to various embodiments, not every embodiment contains only one independent technical solution. This narrative method of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation methods that can be understood by those skilled in the art.

[0059] The series of detailed descriptions listed above are only specific descriptions of feasible embodiments of the present utility model. They are not intended to limit the scope of protection of the present utility model. Any equivalent implementation scheme or changes that do not deviate from the technical spirit of the present utility model, such as combination, division or repetition of features, should be included in the scope of protection of the present utility model.

Claims

1. A superconducting magnet, characterized in that include: A superconducting wire (10) which is wound into a ring shape and is used to form a main magnetic field of a magnetic resonance imaging device, wherein the superconducting wire (10) has a plurality of wire layers (11) distributed in a radial direction (R); as well as An interlayer heat-conducting structure (20) is arranged between two adjacent wire layers (11) along a radial direction (R), and the interlayer heat-conducting structure (20) is used to connect a cold source in a heat-conducting manner.

2. The superconducting magnet according to claim 1, characterized in that The interlayer heat-conducting structure (20) is a metal mesh or a metal foil.

3. The superconducting magnet according to claim 1, characterized in that The interlayer heat-conducting structure (20) is in the shape of a ring extending along the circumferential direction (T).

4. The superconducting magnet according to claim 1, characterized in that The superconducting wire (10) comprises more than three conductor layers (11), and the interlayer heat-conducting structure (20) is arranged between each conductor layer (11) and one or two adjacent conductor layers (11).

5. The superconducting magnet according to claim 1, characterized in that The superconducting magnet comprises a plurality of superconducting wires (10) distributed along an axial direction (A), and the superconducting magnet further comprises a heat transfer unit (30), wherein the heat transfer unit (30) comprises: a main heat source (31) disposed radially (R) outside the plurality of superconducting wires (10) and at least a portion of which extends along the axial direction (A) of the superconducting magnet, the main heat source (31) being used for thermally connecting to a cold source; and Branch heat conductors (32), one end of each branch heat conductor (32) being heat-conductively connected to the main heat conductor (31), and the other end extending into the axial interval of two adjacent superconducting wires (10) and heat-conductively connected to the interlayer heat-conductive structure (20) provided in one or both of the superconducting wires (10).

6. The superconducting magnet according to claim 5, characterized in that The main heat conductor (31) comprises one or a combination of metal plates, metal braids, refrigerant circuits and heat pipes; and / or the branch heat conductor (32) comprises one or a combination of metal plates, metal braids, refrigerant circuits and heat pipes.

7. The superconducting magnet according to claim 5, characterized in that Each of the superconducting wires (10) and the interlayer heat-conducting structure (20) disposed between the wire layers (11) thereof are embedded by an embedding body (40) to form a ring-shaped superconducting coil (50).

8. The superconducting magnet according to claim 7, characterized in that The superconducting magnet further comprises a spacer (60), the spacer (60) being in the shape of a ring extending in the circumferential direction (T) and being fixed between two adjacent superconducting coils (50), the spacer (60) and the embedded body (40) being formed by one-time injection molding, and one end of the branch heat conductor (32) for connecting the interlayer heat conductive structure (20) being embedded in the spacer (60).

9. A magnetic resonance imaging device, characterized in that include: The superconducting magnet according to any one of claims 1 to 8; as well as A cold source (200), the interlayer heat-conducting structure (20) can be thermally connected to the cold source (200).

10. The magnetic resonance imaging apparatus according to claim 9, characterized in that The cold source (200) is a refrigerator.

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