JP2013069664A - Superconductive current lead and superconducting magnet device using superconductive current lead - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a superconductive current lead capable of increasing reliability by preventing a superconductor from being damaged and being efficiently manufactured at low cost, and to provide a superconducting magnet device using the superconductive current lead.SOLUTION: A superconductive current lead has a load support body, and electrodes at both ends of the load support body, respectively, and has a superconductor provided thereon so as to connect between the electrodes. The load support body is made of metal, and the electrodes and the load support body are joined to each other, and the superconductor is supported by the electrodes.

Description

  The present invention relates to a superconducting current lead and a superconducting magnet device using the superconducting current lead.

  For example, Patent Document 1 discloses a superconducting current composed of a current lead support and a plurality of tape-shaped oxide superconductor wires connected to the current terminals at both ends and connected between the current terminals. Lead is disclosed.

JP 2009-230913 A

  In Patent Document 1, a plurality of superconductor wires are brought into contact with the surface of the current lead support to support and fix it. For this reason, it is necessary to smooth the surface of the current lead support in order to prevent damage to the superconductor wire and to improve the adhesion to the current lead support, which causes an increase in manufacturing processes and high costs. It was.

  The present invention has been made in view of the above-described problems of the prior art, and an object of the present invention is to provide a superconducting current lead that can be manufactured efficiently and at low cost while preventing damage to the superconductor and improving reliability.

  In order to solve the above problems, the present invention is a superconducting current lead having a load support, and electrodes at both ends of the load support, each having a superconductor so as to connect the electrodes, The load support body is made of metal, the electrode and the load support body are joined, and the superconductor is supported by the electrode.

  According to the present invention, since the superconductor is supported by the electrode portion, it is not necessary to perform a process such as smoothing on the surface of the load support or to provide a member such as an insulating film or an adhesive, thereby reducing costs. it can. Furthermore, since metal is used as the load support, the difference in thermal shrinkage between the superconductor and the load support is small. For this reason, it becomes possible to prevent damage to the superconductor during cooling without requiring special members or processing.

  Further, since the load support and the electrode are fixed by bonding, it is not necessary to use a separate fixing tool or the like, and the cost can be reduced.

Example of refrigerator-cooled superconducting magnet A perspective view of a superconducting current lead according to the present invention. Side view of superconducting current lead according to the present invention Side view of superconducting current lead according to the present invention Sectional view of a superconducting current lead according to the present invention. Explanatory drawing of the structural example of the connection part of the electrode of a superconducting electric current lead and superconductor which concerns on this invention

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. However, the present invention is not limited to the following embodiments, and the following embodiments are not departed from the scope of the present invention. Various modifications and substitutions can be made.

  FIG. 1 is a cross-sectional view showing a configuration example of the superconducting magnet device 1. The superconducting magnet device 1 according to the present embodiment shows an example in which a superconducting current lead 8 described later with reference to FIG. 2 is applied to a refrigerator-cooled superconducting magnet device. As the refrigerator, for example, a one-stage or two-stage Gifford-McMahon (GM) refrigerator can be used.

  The superconducting magnet device 1 includes a vacuum vessel 2, a superconducting coil 3, a heat transfer member 4, a GM refrigerator 5, a heat shield plate 6, a first stage current line 7, a superconducting current lead 8, and a two stage current line 9. The vacuum vessel 2 has a substantially cylindrical shape. A GM refrigerator 5 is fixed on the upper surface of the vacuum vessel 2. Superconducting coil 3 is formed of a superconducting wire. The superconducting coil 3 is provided in a space surrounded by the heat shield plate 6. The superconducting coil 3 is connected to a low-temperature side cooling stage 5d, which will be described later, via a heat transfer member 4, and is cooled by the GM refrigerator 5 to be in a superconducting state. The superconducting coil 3 is connected to a low temperature side of a superconducting current lead 8 described later. The superconducting coil 3 is supplied with electric power from a power source (not shown) provided outside the vacuum vessel 2 through a first-stage current line 7, a superconducting current lead 8, and a second-stage current line 9 described later.

  The vacuum vessel 2 supports the load of the heat transfer member 4 and the superconducting coil 3 attached to the heat transfer member 4 via a load support.

  The heat shield plate 6 is provided inside the vacuum vessel 2. The heat shield plate 6 is for suppressing radiant heat entering the superconducting coil 3. The heat shield plate 6 is made of a material having a high electric conductivity such as copper or aluminum, and has, for example, a substantially cylindrical shape.

  The GM refrigerator 5 has a multistage cooling cylinder structure including a first stage cooling cylinder 5a and a second stage cooling cylinder 5b. The first-stage cooling cylinder 5 a is inserted into the vacuum vessel 2, and the second-stage cooling cylinder 5 b is inserted into a space surrounded by the heat shield plate 6.

  A high temperature side cooling stage 5c is fixed to the top of the top plate of the heat shield plate 6, and a first stage cooling cylinder 5a is connected to the high temperature side cooling stage 5c. The high temperature side cooling stage 5c is cooled by the first stage cooling cylinder 5a. A second stage cooling cylinder 5b is provided below the top plate of the heat shield plate 6 so as to be connected to the high temperature side cooling stage 5c. A low temperature side cooling stage 5d is connected to the lower end of the second stage cooling cylinder 5b. The low temperature side cooling stage 5d is cooled by the second stage cooling cylinder 5b. The high temperature side cooling stage 5c and the low temperature side cooling stage 5d are formed of a high thermal conductivity member such as copper or aluminum.

  The first-stage current line 7, the superconducting current lead 8, and the second-stage current line 9 are for flowing current from a power source (not shown) to the superconducting coil 3. The power supply passes through the first-stage current line 7, is brought into contact with the heat shield plate 6, is cooled, and is then connected to the high temperature side of the superconducting current lead 8. The low temperature side of the superconducting current lead 8 is connected to a coil electrode (not shown) of the superconducting coil 3 via the heat transfer member 4.

As the first stage current line 7, a material having a high electrical conductivity such as copper or aluminum can be used. As the two-stage current line 9, a material having a high electrical conductivity such as copper or aluminum can be used, or a high-temperature superconducting material such as Bi2223, Bi2212, Y123, or MgB _{2 in} combination with a material having a high electrical conductivity. Can be used.

  In the present embodiment, the refrigerator cooled superconducting magnet device has been described. However, instead of the refrigerator-cooled superconducting magnet device, for example, a liquid-cooled superconducting magnet device using liquid helium as a refrigerant may be used, or a gas-cooled superconducting magnet device using evaporating gas of liquid helium as a refrigerant, for example.

  Next, the superconducting current lead according to the present invention will be described with reference to FIGS.

  2 is a perspective view of a superconducting current lead according to the present invention, FIG. 3 is a side view of the superconducting current lead viewed from the direction A (superconductor installation surface side) in FIG. 2, and FIG. It is the side view seen from the direction. Furthermore, FIG. 5 shows a cross-sectional view taken along line CC ′ in FIG. FIG. 6 shows a configuration example of a connection portion between the electrode and the superconductor.

  As shown in FIG. 2 to FIG. 4, the superconducting current lead 8 of the present invention is provided with electrodes 21 (21 a, 21 b) at both ends of the load support 20, respectively, and the superconductor so as to connect the electrodes 21. 22 is provided.

  The high temperature side electrode 21 a is an electrode terminal provided at one end of the superconducting current lead 8. The high temperature side end 22a of the superconductor 22 is connected to the low temperature side of the high temperature side electrode 21a, and the high temperature side external load absorbing portion 23a is connected to the high temperature side of the high temperature side electrode 21a as shown in the figure. be able to.

  In this case, the high temperature side external load absorption part 23a supports the high temperature side end part 22a of the superconductor 22 via the high temperature side electrode 21a.

  The high temperature side external load absorbing portion 23a prevents the superconducting current lead from being damaged due to the influence of displacement caused by contraction of each member when the superconducting magnet is cooled or the influence of Lorentz force derived from the superconducting magnet during the operation of the superconducting magnet. It is. An elastic member is preferably used for the high temperature side external load absorbing portion 23a. Specifically, a coil spring, a leaf spring, and the like can be exemplified. In the embodiment, a conductor such as a metal is used as the elastic member and functions as a wiring member. However, an elastic member of an insulator separate from the wiring may be used.

  The high temperature side electrode 21a is made of a metal such as copper, aluminum or brass which is a good electrical conductor. Further, the high temperature side electrode 21a and the high temperature side end portion 22a of the superconductor 22 are joined by a conductive material such as solder, indium, conductive resin or the like.

  The low temperature side electrode 21 b is an electrode terminal provided at the other end of the superconducting current lead 8. The high temperature side of the low temperature side electrode 21b is connected to the low temperature side end 22b of the superconductor 22, and the low temperature side of the low temperature side electrode 21b can also be connected to the low temperature side external load absorbing portion 23b. That is, in this case, the low temperature side external load absorbing portion 23b supports the low temperature side end portion 22b of the superconductor 22 through the low temperature side electrode 21b.

  Similarly to the high temperature side external load absorbing portion 23a, the low temperature side external load absorbing portion 23b is superconductive due to the influence of displacement caused by contraction of each member when the superconducting magnet is cooled, and the influence of Lorentz force derived from the superconducting magnet during superconducting magnet operation. The current lead is prevented from being damaged. An elastic member is preferably used for the low temperature side external load absorbing portion 23b. Specifically, a coil spring, a leaf spring, and the like can be exemplified. In the embodiment, a conductor such as a metal is used as the elastic member and functions as a wiring member. However, an elastic member of an insulator separate from the wiring may be used. Thus, although an external load absorption part can be independently provided in each of the high temperature side electrode and the low temperature side electrode, it is more preferable that both have an external load absorption part. That is, it is preferable to provide elastic members at both ends of the superconducting current lead.

  The low temperature side electrode 21b is comprised with metals, such as copper, aluminum, and brass, which are good electrical conductors. Further, the low temperature side electrode 21b and the low temperature side end portion 22b of the superconductor 22 are joined by a conductive material such as solder, indium, or conductive resin.

  The superconductor 22 is provided so as to connect the high temperature side electrode 21a and the low temperature side electrode 21b. The superconductor 22 is provided so as to extend from the high temperature side electrode 21a toward the low temperature side electrode 21b.

As the superconductor 22 may be, for example, Bi-2223-based, Bi2212, Y123, high-temperature superconducting material MgB _2, or the like. Further, when the superconductor 12 is a superconducting tape wire, for example, on a high temperature superconducting wire covered with a multi-core wire such as Bi2223 or Bi2212 using a metal such as silver as a base material or a metal tape base material such as Hastelloy Various superconducting tape wires such as a high-temperature superconducting wire obtained by depositing a thin film such as Y123 on the surface can be used.
The load support 20 is a member connected to the high temperature side electrode 21a and the low temperature side electrode 21b. The load support 20 is made of metal, and the shape is not particularly limited. For example, the load support 20 can have various shapes such as a columnar (cylindrical) shape and a quadrangular prism shape. And from a viewpoint of preventing the heat | fever penetration | invasion via a load support body, it is preferable to have a space (internal space 25) in the inside, and it is more preferable that it is a hollow cylindrical member.

  The metal here is not limited to a single metal, but also includes an alloy, and any metal can be used as long as it is a metal. Specifically, for example, stainless steel, brass, copper, aluminum and the like can be preferably used. Among them, stainless steel having a low thermal conductivity can be preferably used, and austenitic stainless steel can be particularly preferably used. As described above, when a metal is used as the load support, the difference in thermal shrinkage from the superconductor is small, so that the strain applied to the superconductor provided substantially in parallel with the load support during cooling is reduced, resulting in damage. It becomes difficult.

  Here, in the case where the load support body has a space therein, if gas is accumulated in the internal space 25, heat penetration from the high temperature side electrode 21a to the low temperature side electrode 21b may occur through the accumulated gas. There is sex. In addition, during operation of the superconducting magnet device, the gas in the internal space 25 may flow into the vacuum vessel 2, which may deteriorate the degree of vacuum of the vacuum vessel 2.

  Therefore, it is preferable to provide a communication hole 24 that communicates the space in the vacuum vessel 2 and the internal space 25 of the load support 20. For example, as shown in FIG. 2, the communication hole 24 is provided in the electrode (high temperature side electrode 21 a). Can be provided. As a result, the gas in the internal space is easily discharged into the vacuum vessel through the communication hole 24, so that the internal space 25 can be maintained at a degree of vacuum comparable to that of the vacuum vessel 2.

  In the embodiment, the example in which the communication hole 24 is provided in the high temperature side electrode 21a has been described. However, the position of the communication hole 24 is not particularly limited, and may be provided in the load support 20 or the low temperature side electrode, for example. 21b may be provided. A plurality of communication holes 24 may be provided.

  In the superconducting current lead 8 according to the present invention, first, the load support 20 is connected to the high temperature side electrode 21a and the low temperature side electrode 21b, and an integrated body comprising the load support 20, the high temperature side electrode 21a, and the low temperature side electrode 21b is formed. Next, the low temperature side of the high temperature side electrode 21a and the high temperature side end portion 22a of the superconductor 22, and the high temperature side of the low temperature side electrode 21b and the low temperature side end portion 22b of the superconductor 22 are respectively electrically conductive materials such as solder. It is preferable that the superconducting leads 8 are manufactured by connecting them. By manufacturing in this way, it is possible to easily connect the superconductor 22 and the electrode.

  For connection (joining) between the load support 20 and the electrodes (the high temperature side electrode 21a and the low temperature side electrode 21b), welding (fusion welding, pressure welding), brazing, and soldering from the viewpoints of connection strength, ease of connection, and the like. It is preferable to use a connection method using a connection material such as. Specifically, it is possible to connect by inserting the load support 20 into a hole provided in advance in the high temperature side electrode 21a and the low temperature side electrode 21b, and pouring the dissolved connection material between the load support and the hole. it can. Here, if the connection material flows in a large amount and adheres to the surface of the load support, there is a possibility that heat entering the low temperature side through the attached connection material may increase. Therefore, when pouring the connection material, a tape for preventing adhesion of the connection material or a weir for preventing excessive flow of the connection material is installed on the surface of the load support 20, and after connection, these weirs and tape Is preferably removed.

  In addition, when a material having a higher melting point than the conductive material used for connecting the superconductor 22 and the electrode is used as the connection material used for connecting the load support 20 to the high temperature side electrode 21a and the low temperature side electrode 21b, This is preferable because the influence of heat upon connection of the conductive material can be reduced.

  Furthermore, when a gap is provided between the load support 20 and the high temperature side electrode 21a and the low temperature side electrode 21b to increase the thermal resistance of the connection portion, heat penetration from the high temperature side electrode 23a to the low temperature side electrode 23b is prevented. This is preferable because it can be reduced.

  Further, the connection between the high temperature side electrode 21a and the low temperature side electrode 21b and the superconductor 22 is performed by solder plating on the grooves formed in the high temperature side electrode 21a and the low temperature side electrode 21b as shown in FIG. The surface of the groove is thinly covered with solder, the superconductor 22 is loaded into the groove in this state, the melted solder is filled into the groove in the state where the superconductor 8 is loaded, and the solder is solidified. 8 can be securely soldered.

  As another configuration for connecting the electrode and the superconductor 22, the electrode has an electrode block and a superconductor fixing member, and the superconducting fixing member is moved between the superconducting fixing member and the electrode block. The superconductor can be fixed by sandwiching the superconductor.

  The above configuration will be described with reference to FIG. FIG. 6A shows a side view of the high temperature side electrode 21a of the superconducting current lead 8 viewed from the direction A in FIG. FIG. 6B shows a cross-sectional view taken along the line DD ′ in FIG.

  In FIG. 6, the high temperature side electrode 21 a has an electrode block 61 and a superconductor fixing member 62. The superconductor fixing member 62 is configured to be movable on the electrode block 61 in the left and right directions in the drawing, that is, in the direction of the arrow E. Therefore, by moving the superconducting fixing member, the superconductor 22 is fixed by being sandwiched between the electrode block 61 and the superconductor fixing member 62, and the high temperature side electrode 21a and the superconductor 22 are electrically connected. be able to.

  By configuring the connection portion between the electrode and the superconductor as described above, the superconductor 22 can be easily attached to and detached from the electrode, and workability during maintenance can be improved. It is also possible to replace the superconductor 22.

  In FIG. 6, the high temperature side electrode 21 a is described as an example. However, the configuration is not limited to the high temperature side electrode 21 a, and either the high temperature side electrode 21 a or the low temperature side electrode 21 is configured. It can also be set as the structure which concerns about both. For this reason, in the following, they are also simply referred to as electrodes.

  The material of the electrode block 61 is preferably made of a metal such as copper, aluminum, or brass, which is a good electrical conductor, like the high temperature side electrode 21a and the low temperature side electrode 21b described above.

  The superconductor fixing member 62 is not particularly limited as long as the superconductor is sandwiched between the electrode block 61 and the material is not limited, but is preferably made of a conductive material.

  This is because when the superconductor fixing member 62 is made of a conductive material, the superconductor fixing member 62 can be electrically connected to the superconductor 22 and the electrode block 61, and the superconductor fixing member 62 can be electrically connected to the electrodes. This is because the electrical connection area can be increased. For this reason, electrical connection reliability between the electrode and the superconductor 22 can be improved, which is preferable.

  In particular, since it is preferable that the electric conductivity of the entire electrode is equal, the superconductor fixing member 62 is more preferably made of the same material as the electrode block 61.

  The superconducting fixing member 62 preferably has a configuration that can be fixed after the positioning is completed so that the superconductor 22 can be reliably fixed. FIG. 6 shows a configuration in which a fixing screw 63 is provided and the screw 63 is fixed to the electrode block 61 by tightening. However, the configuration is not limited thereto, and the superconductor is fixed by an elastic body or the like, for example. Various fixing means, such as pressing the member 62 against the electrode block 61 and fixing it, can be used.

  When the superconductor 22 is sandwiched and fixed between the electrode block 61 and the superconductor fixing member 62, between the superconductor 22 and the electrode block 61 and / or between the superconductor 22 and the superconductor fixing member 62. In addition, a conductive material such as solder, indium, or conductive resin can be filled and solidified.

  In this case, since these conductive materials are disposed in at least a part of the portion where the superconductor 22 and the electrode are in contact with each other, it is possible to further improve the electrical connection reliability between them.

  However, since the above-described conductive material has a lower electrical conductivity than the electrodes constituting the superconducting current lead and the superconductor, when the conductive material is disposed around the superconductor 22 as described above, It is preferable to adjust the thickness.

  In the case where the electrode has the electrode block 61 and the superconductor fixing member 62 described so far, the conductive material is moved into the gap while the superconductor fixing member 62 is moved and pressed against the electrode block 61 and the superconductor 22. Therefore, the thickness of the conductive material can be adjusted. Thereby, for example, since the thickness of the conductive material can be reduced, it is possible to improve the electrical connection reliability between the electrode and the superconductor 22 and to suppress the decrease in electrical conductivity. Furthermore, since the thickness of the conductive material can be adjusted, it is possible to suppress variation in electrical conductivity between products when a superconducting current lead is used.

  In addition, if bubbles are mixed in the conductive material, the reliability of the connection is lowered. However, the conductive material can be filled while pressing the superconductor fixing portion 62 against the superconductor 22 and the electrode block 61 as described above. In addition, bubbles can be prevented from being mixed when the conductive material is filled.

  As will be described later, when a superconductor is divided into a plurality of superconductor current leads, a plurality of superconductor fixing members are provided on one electrode corresponding to each superconductor, and You can also

  The preferred embodiments of the present invention have been described above, but the present invention is not limited to such specific embodiments, and various modifications can be made within the scope of the gist of the present invention described in the claims. Can be modified or changed.

  For example, in the embodiment, the superconductor current lead is composed of one superconductor, but the number and thickness thereof can be selected according to the required amount of current. When a plurality of superconductors are provided, they can be provided separately at a plurality of locations on the electrode.

  In addition, no insulating film or adhesive is provided between the load support 20 and the superconductor 22, and the superconductor 22 is not supported by the load support 20. However, the installation interval between the load support 20 and the superconductor 22 is not particularly limited, and a part thereof may be in contact. However, when the load support 20 and the superconductor 22 are in contact with each other, the load on the superconductor may be damaged due to the displacement of the load support during cooling or operation stop. As shown in FIG. 2, it is more preferable that the load support 20 and the superconductor 22 are provided apart from each other.

  According to the superconducting current lead of the present invention described above, it is possible to prevent the superconductor from being damaged and improve the reliability, and to manufacture it efficiently and at low cost.

  Therefore, for example, when a superconducting magnet apparatus having the superconducting current lead of the present invention and a superconducting coil connected to the low temperature side of the superconducting current lead is used as shown in FIG. 1, the reliability is high and the cost is low. It becomes possible to provide a superconducting magnet device.

3 Superconducting coil 8 Superconducting current lead 20 Load support 21a, 21b Electrode 22 Superconductor 23a, 23b External load absorbing part (elastic member)
24 Communication hole 61 Electrode block 62 Superconductor fixing member

Claims (11)

A load support, and a superconducting current lead having electrodes at both ends of the load support, and a superconductor provided so as to connect the electrodes,
The load support is made of metal,
The electrode and the load support are joined,
A superconducting current lead, wherein the superconductor is supported by the electrode.   The superconducting current lead according to claim 1, wherein the load support and the superconductor are provided apart from each other.   3. The superconducting current lead according to claim 1, wherein the load support and the electrode are joined by any one of welding, brazing, and soldering.   The superconducting current lead according to any one of claims 1 to 3, wherein the load support is made of stainless steel.   The superconducting current lead according to any one of claims 1 to 3, wherein the load support has a space inside.   The superconducting current lead according to claim 5, further comprising a communication hole communicating with the internal space of the load support.   The superconducting current lead according to claim 6, wherein the communication hole is provided in the electrode. The electrode has an electrode block and a superconductor fixing member,
The superconductor is fixed by moving the superconductor fixing member and sandwiching the superconductor between the superconducting fixing member and the electrode block. Superconducting current lead.   9. The superconducting current lead according to claim 8, wherein the superconductor fixing member is made of a conductive material.   The superconducting current lead according to any one of claims 1 to 9, wherein the superconducting current lead is provided with an elastic member at both ends thereof. Superconducting current lead according to any one of claims 1 to 10,
A superconducting magnet device having a superconducting coil connected to a low temperature side of the superconducting current lead.

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