JP3139925B2 - Superconducting magnet device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superconducting magnet device in which a fluctuating magnetic field acts in an operating environment, such as a superconducting magnet device for a floating railway (linear motor car). The present invention relates to a superconducting magnet device capable of further reducing the eddy current loss of an inner vessel container due to a fluctuating magnetic field and the AC loss in a superconducting coil while minimizing the increase.

[0002]

2. Description of the Related Art FIG. 9 is a sectional view showing an example of the structure of a superconducting magnet device for a floating railway of this kind which is currently under development. In FIG. 9, the superconducting coil 1 is housed in an inner tank 3 together with a refrigerant (for example, liquid helium) 2 and is supported in the inner tank 3 by a fixture 4. The inner vessel 3 is housed in the vacuum insulation space of the vacuum insulation vessel 5 which is the outer vessel, a radiation heat shield plate 6 is provided therebetween, and the support 7 supports the inner vessel 3. I have.

A superconducting magnet device having such a structure must withstand a large load during traveling of a vehicle and maintain an extremely low temperature state for a long time under a limited cooling capacity. Must.

By the way, as shown in the schematic diagram of FIG. 10, a floating railway obtains a propulsive force by a propulsion coil 9 installed on a track 8, and when the vehicle body 10 starts moving in the direction of the arrow 11 shown in FIG. A levitation current is induced in the levitation coil 12 by electromagnetic induction, and a levitation force is obtained to allow the vehicle to travel.

However, the propulsion coil 9 and the levitation coil 12 must be physically arranged in a discrete manner. Therefore, the magnetic field generated by the external ground coil is an ideal magnetic field due to the coil gap. Undulations are produced. Since the unevenness is determined by the arrangement of the ground coil, it is fixed on the ground. When the vehicle crosses the ground when traveling, the superconducting magnet device receives a fluctuating magnetic field accompanying the unevenness. Then, the fluctuating magnetic field is generated by a metal plate (usually an aluminum plate) constituting the vacuum insulation container 5 which is an outer tank container.
To some extent, but still at a non-negligible level.

Generally, when a metal plate receives a fluctuating magnetic field,
It is known that an eddy current is induced in a metal plate by electromagnetic induction. Since this eddy current generates Joule heat, if such a phenomenon occurs on the surface of the inner vessel container 3, it leads to an increase in heat penetration into the superconducting magnet device. Many of the conventional inner tanks 3 are made of stainless steel having a high electric resistance, and the heat penetration due to the eddy current loss is large, which is a problem. Further, it is also known that when an AC magnetic field acts on the superconducting coil 1, heat is generated inside the superconducting coil 1 (AC loss), and the superconducting coil 1 is easily quenched.

Therefore, in order to solve such a problem, a technique of forming a metal film having good conductivity on the surface of the inner tank 3 has recently been adopted, and a good result has been obtained.

More specifically, as shown in FIG. 11, a copper plating 14 is applied to the inner tank container surface 13 as shown in a schematic view of FIG. Since the electric resistance of copper is low, the eddy current loss is greatly reduced, and the fluctuating magnetic field acting on the superconducting coil 1 is also reduced since the fluctuating magnetic field can be more effectively interrupted with a metal having higher conductivity.

However, at present, since the copper plating 14 is a very thin film, the effect of shielding the magnetic field is insufficient, especially in the low frequency range (up to 100 Hz).
Is considered to be inadequate shielding effect.

Of course, by increasing the thickness of the copper plating 14 or adding another metal plate, the shielding effect can be enhanced, but the weight and volume of the entire apparatus are greatly restricted.
Since a dramatic effect cannot be expected with a method of simply adding a good conductor, a solution other than these is strongly demanded.

[0011]

As described above, in a superconducting magnet device in which a fluctuating magnetic field acts in a use environment, such as a conventional floating superconducting magnet device for a railway, a low electric resistance material such as copper plating is added. By doing so, the electric resistance of the surface of the inner vessel is reduced, and the eddy current loss of the inner vessel and the AC loss of the superconducting coil are reduced. However, in this case, the amount of the low electric resistance material that can be added is limited. Therefore, there is a problem that the effect of reducing them is insufficient.

An object of the present invention is to further reduce the eddy current loss of the inner vessel due to the fluctuating magnetic field and the AC loss in the superconducting coil while minimizing the increase in the weight and volume of the entire apparatus. It is to provide a stable superconducting magnet device.

[0013]

In order to achieve the above object, the present invention provides a superconducting coil, an inner vessel container for accommodating the superconducting coil together with its refrigerant, and an inner vessel vessel in a vacuum insulation space. In a superconducting magnet device comprising a vacuum heat insulating container which is an outer vessel container housed in an inner vessel, a plurality of closed loop circuits made of a superconductor are arranged on the surface of the inner vessel vessel.

Here, it is particularly desirable to use a superconductor having a matrix material of a high-resistance metal material such as a copper-nickel alloy or stainless steel as the superconductor constituting each of the closed loop circuits.

It is desirable that the length of the opening of each of the closed loop circuits is shorter than the pole pitch of an external coil which is a source of a fluctuating magnetic field acting from the outside. Further, it is desirable that the length of the opening of each of the above-mentioned closed loop circuits be equal to or less than the pole pitch of the external coil, which is the source of the fluctuating magnetic field acting from the outside, and a length that is a fraction of the integer.

On the other hand, it is desirable that each closed loop circuit is electrically insulated from a base to which the closed loop circuit is attached or a surrounding metal. It is desirable that each of the closed loop circuits is formed by winding a wire coated with an insulating coating.

Further, as each of the closed loop circuits, it is desirable that a plurality of closed loop circuits insulated from each other are arranged at the same position and in the same shape. On the other hand, it is desirable to arrange the closed loop circuits so as to overlap each other without any space.

It is preferable that the contacts of the overlapping closed loop circuits are electrically connected and arranged so as to form a mesh-like electric circuit as a whole. Further, the superconductors constituting each of the closed loop circuits are electrically connected via a stabilizing base material constituting a wire or via a conductor which does not become superconducting so that the time constant of current decay is 1
It is desirable to form a closed loop circuit that takes less than 00 seconds.

On the other hand, the superconductors constituting the closed loop circuits are welded, solid-phase diffusion bonded, ultrasonic bonded, soldered with indium, indium alloy, soldered with tin / lead alloy, or It is desirable to form a closed loop circuit by silver brazing to make an electrical connection.

The material surface of each of the above closed loop circuits is
Gold, silver, copper, aluminum, nickel, chromium, indium,
It is desirable that the surface be coated with tin or an alloy containing them as a base material so that the surface has good electrical conductivity.

Further, each of the above closed loop circuits is formed by welding, solid phase diffusion bonding, ultrasonic bonding, soldering with indium or indium alloy, soldering with tin / lead alloy, or silver brazing. It is desirable to adhere to the surface of the inner tank container.

On the other hand, it is desirable that each of the above-mentioned closed loop circuits is embedded in a plating metal layer or a sprayed metal layer on the surface of the inner vessel container and fixed to the surface of the inner vessel vessel. Further, it is desirable that each of the above-mentioned closed loop circuits is fixed to the surface of the inner vessel container with an epoxy resin or another adhesive.

Further, it is desirable that each of the closed loop circuits is covered with a fiber reinforced resin such as glass fiber, carbon fiber, or aramid fiber, and is fixed to the surface of the inner tank.

Further, it is desirable that a groove-shaped recess having the same planar shape as that of the closed loop circuit is provided on the surface of the inner tank, and each closed loop circuit is arranged along the recess or embedded in the recess.

[0025]

Therefore, in the superconducting magnet device of the present invention,
By arranging a plurality of closed loop circuits composed of superconductors on the surface of the inner vessel container containing the superconducting coils, when a fluctuating magnetic field acts on the inner vessel vessel, the lines of magnetic force that enter the closed loop circuit according to the fluctuations in the magnetic field. In order to eliminate, the shielding current is induced in each closed loop circuit and the magnetic field is shielded, so that the shielding current flowing on the surface of the inner vessel decreases by that much, and the heat generation in the inner vessel is suppressed. .

That is, such an action always occurs in the case of a substance having conductivity. However, if the electric resistance is large, the current is attenuated, so that not only the shielding effect is small, but also a source of Joule heat is generated. In the superconducting magnet device described above, by using a superconductor as the conductive material, the shielding current flows most efficiently without loss due to Joule heat.

Furthermore, in the case of a normal conductive metal, the shielding effect is reduced in a low-frequency magnetic field due to the skin effect. However, the shielding by the superconductor as in the present invention basically has no frequency dependence. Therefore, a good shielding effect can be expected.

The fluctuating magnetic field received by the superconducting magnet device is an AC / moving magnetic field determined by the pole pitch of the ground coil, and is smaller than 1/2 of the pole pitch of the ground coil in the direction of travel of the opening of the closed loop circuit. If the length is large, the change in the magnetic flux in the closed loop circuit is canceled out, and the change in the total magnetic flux becomes small.If the length of the opening is equal to the pole pitch of the ground coil, the fluctuating magnetic field partially increases. Despite the action, the total amount of magnetic flux in the closed loop circuit does not change, and no shielding current flows.

Therefore, in the superconducting magnet device of the present invention, by setting the length of the opening of the closed loop circuit to be equal to or less than the pole pitch of the ground coil, it is possible to always generate a shielding current against a fluctuating magnetic field.

Furthermore, by setting the length of the opening of the closed loop circuit to be an integral fraction of the pole pitch of the ground coil, the shielding effect on each superconducting coil can be made constant. On the other hand, in the superconducting magnet device of the present invention, the closed loop circuit composed of the superconductor is electrically insulated from the surrounding conductors, thereby defining a current path to shield the fluctuating magnetic field with the most efficient arrangement. can do. at the same time,
By insulating the closed loop circuits from each other, a circumferential current loop of the superconducting coil is eliminated, and a circumferential loop current accompanying excitation and demagnetization can be prevented.

Insulation of the superconductor can be easily achieved by winding a superconducting wire provided with an insulating coating. Furthermore, when the current capacity is insufficient with only one wire and the superconducting wire may be quenched, a plurality of closed-loop circuits are superposed at the same position and the shielding induced per wire is provided. Since the current is reduced, the same effect as increasing the current capacity can be obtained.

On the other hand, by eliminating the gap between the closed loop circuits and arranging the closed loop circuits so as to partially overlap each other, it is possible to prevent the magnetic field lines removed from the closed loop circuit from being concentrated by the shielding current in the gaps between the circuits. Can be.

Further, by electrically connecting the contacts of the overlapped closed loop circuit to form a network-like circuit as a whole, a shielding current flows according to the shape of various fluctuating magnetic fields. It can be more flexible than things.

Further, by connecting a superconductor through a stabilizing base material made of a high electric resistance material or through a conductor that does not become superconductive, it is possible to prevent a permanent current from flowing in a closed loop circuit. .

On the other hand, since the surface of the closed loop circuit made of the superconductor with the insulating coating is subjected to metal coating, joining means such as soldering and silver brazing can be used. The closed loop circuit can be easily attached to a metal surface such as a container surface. Alternatively, the closed loop circuit can be easily attached to a metal surface such as an inner tank container surface by embedding the closed loop circuit in a plating metal layer, a sprayed metal layer, or the like.

Even if the surface of the closed loop circuit made of the superconductor is still insulated, the use of an epoxy resin or other adhesive suitable for extremely low temperatures can be used.
A closed loop circuit can be fixed to the surface of the inner tank container. Alternatively, the closed loop circuit can be easily attached to the surface of the inner vessel container by wrapping the surface of the inner vessel vessel together with the closed loop circuit with the fiber reinforced resin.

Further, a groove-shaped concave portion is provided on the surface of the inner vessel container in accordance with the shape of the closed loop circuit composed of the superconductor.
By embedding a closed loop circuit therein or disposing it along a recess, the closed loop circuit can be easily attached to the inner tank vessel surface.

[0038]

Embodiments of the present invention will be described below in detail with reference to the drawings. (First Embodiment) FIG. 1 is a schematic diagram showing a configuration example of a superconducting magnet device for a floating railway according to a first embodiment of the present invention. The same elements as those in FIGS. The description is omitted here, and only different parts will be described here.

That is, in the floating superconducting magnet device of this embodiment, as shown in FIG. 1, a plurality of closed loop circuits 15 made of a superconductor are arranged on the surface 13 of the inner tank 3 containing the superconducting coil 1. However, each closed loop circuit 15 is configured to be electrically insulated.

Further, a closed loop circuit 15 comprising a superconductor
The length of the opening in the traveling direction 11 (the direction of the arrow in the figure) is
As shown in FIG. 2, the pole pitch of the external coil (ground coil) is 18 or less, preferably a fraction of an integer, and more preferably a half or less. It has been given appropriate resistance.

Next, in the superconducting magnet device for a levitation type railway of the present embodiment configured as described above, the superconducting coil 1
When a fluctuating magnetic field acts on the inner vessel 3 by arranging a plurality of closed loop circuits 15 made of a superconductor on the surface 13 of the inner vessel 3 in which the liquid is stored, the closed loop circuit 15 enters the closed loop circuit 15 in accordance with the fluctuation of the magnetic field. Since the shielding current 16 is induced in each closed loop circuit 15 and the magnetic field is shielded so as to eliminate the lines of magnetic force, the shielding current 16 flowing to the surface 13 of the inner tank 3 is reduced by that much, and the inner tank is reduced. Heat generation in the container 3 is suppressed.

That is, such an action always occurs in the case of a substance having conductivity. However, if the electric resistance is large, the current is attenuated, so that not only the shielding effect is small but also a source of Joule heat.

Therefore, in the superconducting magnet device of the present embodiment, by using a superconductor as a conductive material, the shielding current flows most efficiently without loss due to Joule heat.

Further, in the case of a normal conducting metal, the shielding effect is reduced in a low-frequency magnetic field due to the skin effect. However, in the case of shielding by a superconductor as in this embodiment, there is basically no frequency dependence. A good shielding effect can be expected from the frequency.

As shown in FIG. 2, the fluctuating magnetic field 17 received by the superconducting magnet device is an AC / moving magnetic field determined by the pole pitch 18 of the ground coil. If the length of the opening of the closed loop circuit in the traveling direction is larger than (19) than (20), the change in the magnetic flux in the closed loop circuit 15 is canceled out, and the change in the total magnetic flux becomes small. Is equal to the pole pitch 18 of the ground coil (21), the total magnetic flux in the closed loop circuit 15 does not change and the shielding current does not flow even though the fluctuating magnetic field is partially applied.

Therefore, in the superconducting magnet device of the present embodiment, by setting the length of the opening of the closed loop circuit 15 to be equal to or less than the pole pitch 18 of the ground coil, the shielding current 16 against the fluctuating magnetic field can always be generated. .

Further, the length of the opening of the closed loop circuit 15 is set to be an integral number (a half) of the pole pitch 18 of the ground coil.
By doing so, the shielding effect on each superconducting coil 1 can be made constant.

On the other hand, in the superconducting magnet device of the present embodiment, the closed loop circuit 15 composed of the superconductor is electrically insulated from the surrounding conductors, thereby defining a current path and providing the most efficient arrangement. It can shield the fluctuating magnetic field. At the same time, by insulating the closed loop circuits 15 from each other, the circumferential current loop of the superconducting coil 1 is eliminated, and a circumferential loop current accompanying excitation and demagnetization can be prevented.

The insulation of the superconductor can be easily achieved by winding a superconducting wire provided with an insulating coating. Furthermore, when the current capacity is insufficient with only one wire and the superconducting wire may be quenched, a plurality of closed loop circuits 15 are induced per wire by arranging them in the same position. Since the shielding current 16 is reduced, the same effect as increasing the current capacity can be obtained.

As described above, the levitation type superconducting magnet device of this embodiment has a plurality of closed loop circuits 15 made of a superconductor arranged on the surface 13 of the inner tank 3 containing the superconducting coil 1. The closed loop circuit 15 is electrically insulated, and the length of the opening of the closed loop circuit 15 made of a superconductor is set to be equal to or less than the pole pitch 18 of the external coil (ground coil), and desirably an integral number (half). It has the following length, is further appropriately insulated, and has an appropriate resistance for each closed loop circuit 15.

Therefore, the closed loop circuit 1 comprising the superconductor
5, the fluctuating magnetic field acting on the inner vessel 3 can be reduced, and the heat generation of the inner vessel 3 can be suppressed. As a result, a metal film having good conductivity such as copper plating is formed on the surface of the inner vessel container 3 as described above,
Also, it is not necessary to add a good conductor such as increasing the thickness or adding another metal plate. The eddy current loss of the inner vessel 3 due to the magnetic field 17 and the AC loss in the superconducting coil 1 are further reduced, and a stable superconducting magnet device that consumes less refrigerant (liquid helium) 2 can be obtained.

(Second Embodiment) FIG. 3 is a schematic diagram showing a configuration example of a superconducting magnet device for a floating railway according to a second embodiment of the present invention. The same reference numerals are given and the description is omitted, and only different portions will be described here.

That is, as shown in FIG. 3, the floating superconducting magnet device for a levitation type railway according to the present
5 are arranged so as to overlap each other without an interval.

Also in this case, as in the case of the first embodiment, the length of the traveling direction 11 of the opening of each closed loop circuit 15 is less than half the pole pitch 11 of the ground coil. It is desirable to do.

Next, in the superconducting magnet device for a levitation type railway according to the present embodiment configured as described above, the superconducting coil 1 is used.
Are arranged on the surface 13 of the inner vessel 3 in which superconductors are stored, and furthermore, gaps between the closed loop circuits 15 are eliminated, and the closed loop circuits 15 are partially overlapped. Since the magnetic field lines removed from the closed loop circuit 15 by the shielding current 16 can be prevented from concentrating (entering) in the gap between the closed loop circuits 15, the magnetic field lines can be prevented from being compared with the first embodiment. In addition, the effect of suppressing heat generation is further enhanced.

Also in this case, each closed loop circuit 15
By setting the length of the opening in the traveling direction 11 to be not more than half of the pole pitch 11 of the ground coil, the above-mentioned shielding effect is further enhanced.

Further, a closed loop circuit 1 comprising a superconductor
If the electrical resistance between the five is sufficiently high, a circuit without insulation can be arranged. Alternatively, if the electrical resistance is not high enough and the current path along the circumferential direction of the race track occurs to a considerable extent, an insulated circuit and a non-insulated circuit may be alternately or mixedly arranged. , The current path along the circumferential direction can be cut off.

(Third Embodiment) FIG. 4 is a schematic diagram showing a configuration example of a superconducting magnet device for a floating railway according to a third embodiment of the present invention. The same elements as those in FIGS. The same reference numerals are given and the description is omitted, and only different portions will be described here. FIG. 4 shows only a part of the circuit.

That is, as shown in FIG. 4, the floating superconducting magnet device of the present embodiment electrically connects the electrical contacts 22 of the closed loop circuit 15 composed of the superconductors arranged so as to overlap each other. They are connected and arranged so as to form a mesh-like electric circuit as a whole.

Next, in the levitation type superconducting magnet device of the present embodiment configured as described above, the electrical contacts 22 of the overlapped closed loop circuit 15 are electrically connected to each other to form a net-like network. By forming an electric circuit, the shielding current 16 corresponding to the shape of various fluctuating magnetic fields 17
Flows, the flexibility can be increased as compared with the case of a fixed circuit pattern.

When a current path along the circumferential direction of the race track occurs, for example, as shown in a schematic diagram of FIG. 5, a closed loop circuit 15a electrically insulated from the surroundings
Can partially cut off the current path.

The present invention is not limited to the above embodiments, but can be implemented in the following manner. (A) In each of the above embodiments, the case where the closed loop circuit 15 is arranged in a plane has been described, but the present invention is not limited to this.
In either case, by connecting the superconductor through a stabilizing base material made of a high electric resistance material or through a conductor that does not become superconductive, a permanent current is prevented from flowing through the closed loop circuit. It becomes possible.

(B) In each of the above embodiments, the surface of the closed-loop circuit 15 made of a superconductor coated with an insulating coating is subjected to a metal coating treatment so that joining means such as soldering and silver brazing can be used. A closed loop circuit 15 is formed on a metal surface such as the inner tank container surface 13 by the means described above.
Can be easily fixed.

(C) In each of the above embodiments, for example, FIG.
As shown in (1), the closed loop circuit 15 is embedded in the plating metal layer, the sprayed metal layer 23 and the like, so that the closed loop circuit 15 can be easily fixed to the metal surface such as the inner tank surface 13.

(D) In each of the above embodiments, even if the surface of the closed loop circuit 15 made of a superconductor is still insulated, the epoxy resin or other adhesive suitable for cryogenic temperatures can be used. The closed loop circuit 15 can be easily fixed to the inner tank surface 13.

(E) In each of the above embodiments, for example, FIG.
As shown in (2), the closed loop circuit 15 can be easily fixed to the inner tank container surface 13 by wrapping the inner tank container surface 13 together with the closed loop circuit 15 by the fiber reinforced resin 24.

(F) In each of the above embodiments, for example, FIG.
As shown in the figure, a groove-like concave portion 25 is provided on the inner tank container surface 13 in accordance with the shape of the closed loop circuit 15 made of a superconductor, and the closed loop circuit 15 is embedded in the concave portion 25 or along the concave portion 25. By arranging, the closed loop circuit 15 can be easily fixed to the inner tank surface 13.

(G) In each of the above embodiments, the method shown in FIG. 6 and the method shown in FIG. 8 or the method shown in FIG. 7 and the method shown in FIG. 8 are appropriately combined. You may do so.

(H) In each of the above embodiments, by providing a good conductor such as copper plating on the inner tank vessel surface 13, it becomes an auxiliary magnetic field shielding means, and further contributes to the reduction of heat generation. Becomes possible.

(I) In each of the above embodiments, if the electric resistance between the closed loop circuits 15 made of a superconductor is sufficiently high and is about 100 times or more the electric resistance via copper, each closed loop circuit 15 There is no need to provide insulation.

[0071]

As described above, according to the present invention, a superconducting coil, an inner vessel container for accommodating the superconducting coil together with its refrigerant, and an outer vessel for accommodating the inner vessel vessel in a vacuum insulating space. In a superconducting magnet device consisting of a vacuum insulated container, which is a container, a plurality of closed loop circuits made of superconductors are arranged on the surface of the inner container, minimizing the weight and volume of the entire device. While holding down
A stable superconducting magnet device capable of further reducing the eddy current loss of the inner vessel container due to the fluctuating magnetic field and the AC loss in the superconducting coil can be provided.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a first embodiment of a floating superconducting magnet device for a railway according to the present invention.

FIG. 2 is a conceptual diagram for explaining an effective length of a closed loop circuit composed of a superconductor in a levitation type superconducting magnet device for a railway according to the present invention.

FIG. 3 is a schematic view showing a second embodiment of a floating superconducting magnet device for a railway according to the present invention.

FIG. 4 is a schematic diagram showing a third embodiment of a floating superconducting magnet device for a railway according to the present invention.

FIG. 5 is a schematic diagram showing a modification of the third embodiment of the levitation type superconducting magnet device for a railway according to the present invention.

FIG. 6 is a schematic view showing another embodiment of the superconducting magnet device for a floating railway according to the present invention.

FIG. 7 is a schematic view showing another embodiment of a superconducting magnet device for a floating railway according to the present invention.

FIG. 8 is a schematic view showing another embodiment of a superconducting magnet device for a floating railway according to the present invention.

FIG. 9 is a sectional view showing a configuration example of a superconducting magnet device for a floating railway.

FIG. 10 is a schematic diagram schematically showing a track plane of a floating railway.

FIG. 11 is a schematic view showing a configuration example of an inner tank container in a conventional floating superconducting magnet device for a railway.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Superconducting coil, 2 ... Refrigerant (liquid helium), 3 ... Inner vessel container, 4 ... Fixing fitting, 5 ... Vacuum insulation container, 6 ... Radiant heat shield plate, 7 ... Supporting material, 8 ... Track, 9 ... Propulsion coil, Reference Signs List 10: car body, 11: traveling direction, 12: floating coil, 13: inner tank vessel surface, 14: copper plating, 15: closed loop circuit, 15a: closed loop circuit insulated from surroundings, 16: shielding current, 17: fluctuating magnetic field, 18: Pole pitch of the ground coil 19: Loop cross section equivalent to 1/2 of the pole pitch of the ground coil 20: Loop cross section of 1/2 or more of the pole pitch of the ground coil 21: Loop equal to the pole pitch of the ground coil Cross section, 22: electrical contact, 23: plated or sprayed metal layer, 24: fiber reinforced resin, 25: groove-shaped recess.

────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tomohisa Yamashita 1 Toshiba-cho, Fuchu-shi, Tokyo Inside the Toshiba Fuchu factory (58) Fields investigated (Int. Cl. ⁷ , DB name) H01F 6/00

Claims (17)

(57) [Claims] 1. A superconducting coil, an inner vessel container for accommodating the superconducting coil together with a refrigerant therein, and a vacuum heat insulating vessel which is an outer vessel vessel for accommodating the inner vessel vessel in a vacuum heat insulating space. In the superconducting magnet device, a plurality of closed loop circuits made of a superconductor are arranged on a surface of the inner vessel container. 2. The superconductor according to claim 1, wherein a superconductor using a high-resistance metal material such as a copper-nickel alloy or stainless steel as a matrix material is used as a superconductor constituting each of the closed-loop circuits. Superconducting magnet device. 3. The length of the opening of each closed loop circuit is
The superconducting magnet device according to claim 1 or 2, wherein the length of the superconducting magnet is less than a pole pitch of an external coil that is a source of a fluctuating magnetic field acting from the outside. 4. The length of the opening of each closed loop circuit is
The superconducting magnet according to claim 1 or 2, wherein the length of the external coil, which is a source of a fluctuating magnetic field acting from the outside, is equal to or less than the pole pitch and is a length that is a fraction of the integer. apparatus. 5. The apparatus according to claim 1, wherein each of the closed loop circuits is electrically insulated from a base on which the closed loop circuit is mounted or a surrounding metal. Superconducting magnet device. 6. The superconducting magnet device according to claim 1, wherein each of the closed loop circuits is formed by winding a wire coated with an insulating coating. 7. The closed loop circuit according to claim 1, wherein a plurality of closed loop circuits insulated from each other are arranged at the same position and in the same shape. The superconducting magnet device according to claim 1. 8. The superconducting magnet device according to claim 1, wherein the closed-loop circuits are arranged so as to overlap each other without an interval. 9. The superconducting magnet according to claim 8, wherein the contacts of each of the overlapping closed loop circuits are electrically connected and arranged so as to form a net-like electric circuit as a whole. apparatus. 10. A superconductor constituting each of the closed loop circuits is electrically connected via a stabilizing base material constituting a wire or via a conductor which does not become superconductive, and a time constant of current decay is 100. The superconducting magnet device according to any one of claims 1 to 9, wherein a closed loop circuit having a duration of seconds or less is formed. 11. The superconductor constituting each of the closed loop circuits is welded, solid phase diffusion bonded, ultrasonic bonded, soldered with indium, indium alloy, soldered with tin / lead alloy, or The superconducting magnet device according to any one of claims 1 to 10, wherein a closed loop circuit is formed by being electrically connected by silver brazing. 12. The material surface of each said closed loop circuit,
Gold, silver, copper, aluminum, nickel, chromium, indium,
The superconducting magnet device according to any one of claims 1 to 11, wherein the superconducting magnet device is coated with tin and an alloy containing the same as a base material, and has a surface having good electric conductivity. . 13. Each of the closed loop circuits is formed by welding, solid phase diffusion bonding, ultrasonic bonding, solder bonding with indium, indium alloy, solder bonding with tin-lead alloy, or silver brazing. The superconducting magnet device according to any one of claims 1 to 11, wherein the superconducting magnet device is fixed to a surface of the inner vessel container. 14. The method according to claim 1, wherein each of the closed loop circuits is embedded in a plated metal layer or a sprayed metal layer on the surface of the inner vessel and fixed to the surface of the inner vessel. The superconducting magnet device according to any one of the above. 15. The method according to claim 1, wherein each of the closed loop circuits is fixed to a surface of the inner vessel container with an epoxy resin or another adhesive. Superconducting magnet device. 16. The method according to claim 16, wherein each of the closed loop circuits comprises
The superconducting magnet device according to any one of claims 1 to 11, wherein the superconducting magnet device is covered with a fiber reinforced resin such as carbon fiber or aramid fiber and is fixed to a surface of the inner vessel container. 17. A groove-shaped recess having the same planar shape as that of the closed loop circuit is provided on the surface of the inner tank, and each closed loop circuit is arranged along the recess or embedded in the recess. The superconducting magnet device according to any one of claims 1 to 11, wherein: