JPH06132566A - Superconducting magnet - Google Patents

Abstract

PURPOSE:To utilize a power lead wire as an absorber of a frictional heat occurring between a coil and a support fitment for a permanent current mode since the power lead wire used in energizing a superconducting coil is not used and thus the space is wasted when the superconducting coil is the permanent current mode. CONSTITUTION:A power lead wire 6 is connected to a start and an end of winding of a superconducting coil 1 and is wound in an alignment close winding by one layer of coil and is integrally molded in the coil 1. The molded body is tightened by a linear 7 and a support member 8 and is held in an inner bath 9 with a cryogenic temperature. Accordingly, a frictional heat occurring between the coil 1 and the support member 8 due to a vibration from the outside is absorbed by the power lead wire 6, and a quenching of the superconducting coil 1 is prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superconducting magnet used for running a vehicle on a magnetic levitation railway or for nuclear magnetic resonance imaging (MRI).

[0002]

2. Description of the Related Art A superconducting magnet used for a magnetic levitation railway, nuclear magnetic resonance imaging (MRI), etc., contains a superconducting coil in which a superconducting wire is wound in a number of closely aligned windings in an inner tank which is a cryogenic container. The magnetic field is generated by passing an electric current through this superconducting coil.

This superconducting coil is used in the permanent current mode because it is necessary to keep a constant current flowing for a long time. The persistent current mode is a state in which the superconducting coil is closed loop to confine the current.

The superconducting coil and its persistent current mode will be described with reference to FIGS.

In order to pass a current through the superconducting coil 1, first, the external power source 3 and the external power lead wire 4 are connected to the superconducting magnet 2. With the permanent current switch 5 turned off, the superconducting coil 1 is fed from the external power source 3 through the external power lead wire 4 and the power lead wire 6 inside the superconducting magnet.
An electric current is applied to (FIG. 7).

When the permanent current switch 5 is turned on after reaching the specified current value, the current becomes a closed loop between the superconducting coil 1 and the permanent current switch 5, and no current flows through the power lead wire 6 ( (Figure 8). After that, the external power source 3 and the external power lead wire 4 are removed, and the superconducting magnet is maintained in the permanent current mode to be in the energized state.

By the way, usually, the power lead wires 4 and 6 are made of a material having excellent conductivity such as a superconducting wire or copper.

Superconducting coil 1 used for magnetic levitation railway
In this case, a permanent current switch 5 and a power lead wire 6 for supplying a current from the outside are connected and arranged in a configuration as shown in the drawings (FIGS. 9 and 10).

Superconducting coil 1 used for magnetic levitation railway
Is a mold in which a superconducting wire whose stabilizing base material is copper is wound in a racetrack shape in an arrayed dense winding in multiple stages. The molded superconducting coil 1 is housed in an inner tank 9 which is a cryogenic container via a plurality of liners 7 and a supporting member 8. The inner tank 9 is filled with liquid helium as a coolant to form the superconducting coil 1. Maintain superconductivity.

The support 8 is usually non-magnetic and made of highly rigid stainless steel. This support 8 is used as a superconducting coil 1.
If it is directly fixed to the superconducting wire 1, a large frictional heat is generated due to the deviation generated at the contact surface between the superconducting coil 1 and the supporting member 8 due to the large friction coefficient of stainless steel, and this heat cannot be absorbed by the liquid helium and is transmitted to the superconducting wire 1. , There is a risk of causing superconducting breakdown.

To alleviate this frictional heat generation, a liner 7 made of a material having a low coefficient of friction is interposed between the support and the superconducting coil.

[0012]

The superconducting coil 1 used in the magnetic levitation railway receives vibrational energy larger than the outside. Due to the influence of this vibration, frictional heat is generated between the liner 7 and the superconducting coil 1. The liner 7 uses a material with a low coefficient of friction to keep its calorific value small. However, if the calorific value exceeds the cooling capacity of liquid helium, it will exceed the critical temperature of the superconducting coil 1 and cause superconducting destruction. There is a risk of waking up.

In the present invention, the frictional heat generated between the liner and the superconducting coil due to the vibration energy is not easily transmitted to the superconducting wire inside the superconducting coil, and the superconducting coil is prevented from reaching the temperature at which the superconducting destruction occurs. The purpose is to improve the stability of the coil.

[0014]

To achieve the above object, in the present invention, the connecting portion of the power lead wire 6 is connected to the superconducting coil 1.
The power lead wire 6 is provided on the inner and outer surfaces of the superconducting coil 1 to form a single layer, and a part of the power lead wire 6 is integrally molded with the superconducting coil 1.

[0015]

[Operation] The superconducting coil confines the current in a closed loop,
Permanent current mode used. Therefore, in this state, no current flows through the power lead wire.

Due to the structure in which a part of the power lead wire is interposed between the inner peripheral surface and the outer peripheral surface of the superconducting coil, friction heat generated between the superconducting coil and the liner is generated. The wire absorbs and reduces heat invasion into the superconducting coil.

[0017]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described based on the embodiments shown in FIGS.

Superconducting coil 1 at the beginning and end of the superconducting coil
The lead wire 10 and the power lead wire 6 are connected to each other, the power lead wire is wound by one layer, and these are molded integrally with the superconducting coil.

As described above, the surface of the inner and outer layers of the molded superconducting coil 1 is formed by aligning the power lead wires 6 using a copper material or a superconducting wire containing copper as a base material, which has good electrical conductivity and thermal conductivity. The power lead wire 6 and the superconducting coil lead wire 10 are connected to the superconducting coil 1 at the connection portion 13 of the power lead wire 6 inside thereof, and further, the superconducting coil 1 is aligned and densely wound a number of times inside thereof. It will be in the state of being.

There are two methods for tightly winding the power lead wire 6 on the inner and outer circumferences. One is a method of simply and closely winding the power lead wires 6 in a coil shape (FIG. 3). However, since it is coiled, a magnetic field is generated when a current flows through the power lead wire 6 during energization.

Although there is no particular problem in use in this structure, in the case of a structure that does not generate a magnetic field, as another method, as shown in FIG. 4, the current directions (arrows) of the adjacent power lead wires 6 are reversed. If it is bent and rolled up so as to become (non-induction winding), the magnetic field will not be generated.

With this structure, the frictional heat generated between the liner 7 and the superconducting coil 1 due to the vibration energy is
The heat is dissipated to the power lead wire 6 having good thermal conductivity, and the temperature of the power lead wire 6 rises. Since the power lead wire 6 and the superconducting coil 1 are always cooled by liquid helium as a coolant, the temperature of the power lead wire 6 decreases with time.

Since the frictional heat generated by the vibration energy from the outside is dissipated in the power lead wire 6, the temperature rise of the superconducting coil 1 is significantly reduced, and the superconducting breakdown is less likely to occur than in the conventional case.

Another embodiment of the present invention will be described (see FIG. 5).

The superconducting coil 1 is arranged in parallel with the power lead wire 6.
A copper wire or a superconducting wire 12 independent of the above is interposed between the power lead wires to form a superconducting coil. Even in this case, the action and effect are the same as above.

Further, as another embodiment (FIG. 6), the permanent current switch 5 is arranged in the center of the superconducting coil 1 to improve the space factor of the whole arrangement.

[0027]

According to the present invention, the frictional heat generated between the liner and the superconducting coil due to the vibration energy from the outside is dissipated to the power lead wire and the frictional heat transmitted to the superconducting coil can be reduced.

As a result, the superconducting coil becomes a superconducting coil that is more resistant to superconducting destruction than before and has improved stability.

[Brief description of drawings]

FIG. 1 is a sectional view of a superconducting coil of the present invention,

2A is a sectional view of a superconducting magnet according to the present invention, FIG. 2B is an electrical configuration diagram of FIG.

FIG. 3 is a perspective view of FIG.

FIG. 4 is a perspective view of a superconducting magnet according to another embodiment of the present invention,

FIG. 5 is a partial sectional view of a coil of a superconducting magnet according to still another embodiment of the present invention,

FIG. 6 is a sectional view showing the configuration of a third embodiment of the present invention;

FIG. 7 is an electrical configuration diagram of a conventional superconducting magnet,

FIG. 8 is an operation explanatory diagram of FIG. 7;

FIG. 9 is a configuration diagram of a conventional superconducting magnet,

FIG. 10 is a partial perspective sectional view of FIG.

[Explanation of symbols]

 1 ... Superconducting coil 2 ... Superconducting magnet 3 ... External power supply 4, 6 ... Power lead wire 5 ... Permanent current switch 9 ... Inner tank 7 ... Liner 8 ... Supporting tool 9 ... Inner tank 12 ... (for heat absorption) Copper wire

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Tatsumi Yamane No. 1 Toshiba-cho, Fuchu-shi, Tokyo Toshiba Corporation Fuchu factory inside

Claims (4)

[Claims] 1. A superconducting magnet having a multi-layered layer of closely packed windings and formed in a racetrack shape, the superconducting coil being housed in a cryogenic inner tank through a support, wherein at least the superconducting coil is wound. A superconducting magnet comprising a superconducting coil connected to a power lead wire wound one layer at the beginning end or the winding end end. 2. The superconducting magnet according to claim 1, wherein a copper wire or a superconducting wire is wound between the windings of the power lead wire connected to the end of the superconducting coil in parallel with one winding. 3. The superconducting magnet according to claim 1, wherein a coil lead wire is connected to a connecting portion between the power lead wire and the superconducting coil and these are integrally molded. 4. The superconducting magnet according to claim 1, wherein the power lead wire wound in connection with the end of the superconducting coil is non-inductively wound.