JPH07105615B2 - Magnetic shield method using superconducting single crystal powder - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a magnetic shield method for shielding an external magnetic field or for preventing an internally generated magnetic field from being emitted to the outside. The present invention relates to a magnetic shield method using a superconducting single crystal powder in the magnetic shield part of an apparatus.

[0002]

2. Description of the Related Art Conventionally, for example, a room-like structure for accommodating a living body and diagnosing the living body by detecting a weak biomagnetic signal such as a magnetocardiographic wave, a brain magnetic wave, and a pulmonary magnetic wave generated by the living body In the case of the bio-diagnosis device, it is difficult to perform accurate bio-diagnosis unless the external magnetism is almost completely cut off. Therefore, a magnetic shield method has been considered in which a metal having a high magnetic permeability such as iron is used to completely surround the biopsy device. Further, for example, in the case of a magnetic levitation type linear train, a strong magnetic field is generated from the coil on the ground side and the magnet on the vehicle body side. Therefore, the influence of magnetism on the human body must be reduced. At least the floor portion must be magnetically shielded with a metal having high magnetic permeability.

In the above conventional magnetic shield method,
In place of the high magnetic permeability metal, a bulk of a superconductor or a metal substrate having an oxide superconductor coated on the surface may be used. Further, the oxide superconductor powder may be kneaded with an organic solvent and formed into a film plate by the doctor blade method.

[0004]

According to the above-mentioned conventional magnetic shield method, the magnetic shield method using a metal having a high magnetic permeability such as iron generally has a large weight of metal. There is a problem that the weight of the device itself becomes large and the cost becomes high. In particular, it is fatal in the case of a magnetic levitation type linear train in which the weight of the vehicle must be reduced as much as possible. The method of magnetic shielding using a bulk of a superconductor or an oxide superconductor coated on the surface of a metal substrate is to prepare a magnetic shield body having a complicated or large size. However, there is a problem that it is not versatile and that a sufficient shield effect cannot be expected. Therefore, in the present invention,
Or even if it is a large-sized magnetic shield body, it is a technical problem to be solved to make it lightweight and easily form a sufficient shield effect at low cost. To do.

[0005]

[Means for Solving the Problems] The technical means for solving the above-mentioned problems is to provide a heat insulating layer composed of a vacuum space and the heat insulating layer.
Adjacent to the cooling layer filled with liquid nitrogen, and the cooling layer
Laminated magnetic shield layer that is cooled further to the required shape
In the magnetic shield layer of the magnetic shield part integrated into
The bismuth-based mixture was melted in the empty space.
And quenching the melt to a solid state,
The bismuth-based mixture that has become
Crystals were deposited and the single crystals were converted into powders to obtain supercurrent.
By uniformly compacting the conductive single crystal powder,
-The outer peripheral part of the device requiring the magnetic field is magnetized by the magnetic shield part.
It is to shield the air.

[0006]

According to the magnetic shield method using the above-mentioned superconducting single crystal powder, the magnetic shield is applied to the outer peripheral portion of the device requiring the magnetic shield.
The magnetic shield part is formed and the magnetic shield part of the magnetic shield part is formed.
When the superconducting single crystal powder is compactly packed in the hollow part of the shield layer,
In fact, the superconducting single crystal powder is cooled to below the critical temperature in the cooling layer.
Meisuna possessed by the superconducting single crystal powder for cooling
-The effect shields magnetism from outside the device.

[0007]

Embodiments of the present invention will now be described with reference to the drawings. FIG. 1 is a vertical cross-sectional view of the biopsy device 1.
When a person 3 lying on the bed 2 is to be precisely diagnosed in the biopsy device 1, a cardiac magnetic wave, a brain magnetic wave, a pulmonary magnetic wave, a myomagnetic field,
The person 3 is diagnosed by detecting a weak biomagnetic signal such as an eyeball magnetic field or a retinal magnetic field with the magnetic sensor 4 and inputting the biomagnetic signal to the measuring device 5 for analysis.

Therefore, even if a weak magnetism that affects the biomagnetic signal from the outside of the biodiagnosis apparatus 1 intrudes from the outside, accurate biodiagnosis cannot be performed. Is provided with a magnetic shield portion 6 of a thick compacted and packed layer so as to cover the biopsy device 1. The magnetic shield part 6 is composed of a main body magnetic shield part 6A provided on the main body side of the biometric diagnosis device 1 and a door magnetic shield part 6B provided on the door side of the biopsy device 1. The diagnostic device 1 is completely covered.

As shown in FIG. 1, the main body magnetic shield portion 6 is provided.
A and the door magnetic shield part 6B both have vacuum spaces 7A and 7B as heat insulating means at the outermost parts, and cooling parts 8A and 8B filled with liquid nitrogen N are provided inside thereof. . Further, shield layers 9A and 9B having a thickness satisfying a required magnetic shield effect, which is compactly filled with bismuth (Bi) -based high temperature superconducting single crystal powder SP, are formed inside thereof.

The bismuth high temperature superconducting single crystal powder SP is
By heating the bismuth-based mixture at, for example, 1150 ° C. for a required time to make it in a molten state, quenching the melt to a solid state, and then heat-treating the solid-state bismuth-based mixture at, for example, 850 ° C. for a required time. It is obtained by precipitating short fibrous crystals and powdering the short fibrous crystals with a fine powder mill. The bismuth-based high-temperature superconducting single crystal powder SP thus obtained can be compacted and packed into a shield layer space having a considerably complicated or large shape.

Bismuth-based high temperature superconducting single crystal powder SP
Of the shield layer 9A with the shield layer space filled with
In 9B, the bismuth-based high-temperature superconducting single crystal powder SP is cooled below the critical temperature by the cooling action of the cooling parts 8A and 8B filled with liquid nitrogen N, so the Meissner effect of the bismuth-based high-temperature superconducting single crystal powder SP is obtained. According to the above-mentioned biological diagnosis device 1
It shields the magnetism from the outside. Moreover, since the bismuth-based high-temperature superconducting single crystal powder SP has a small thermal conductivity, it has a heat insulating effect, and the power of the cooling device for cooling the cooling units 8A and 8B of the biological diagnostic device 1 can be reduced.

Next, the bismuth type high temperature superconducting single crystal powder SP is applied to a magnetic levitation linear train 1 as shown in FIG.
1 is used for the magnetic shield portion 13 formed on the lower floor and left and right side portions of the vehicle body 12 of each vehicle, and the ground coils 14, 1
5. An embodiment will be described in which the strong magnetism generated from the superconducting coil 16 and the like is shielded to prevent the strong magnetism from adversely affecting the passengers and passengers in the vehicle compartment.

As shown in FIGS. 2 and 3, the magnetic shield portion 1 provided on the lower portion of the vehicle compartment floor and the left and right side portions of the vehicle body 12.
3, a vacuum space 13A as a heat insulating means is formed at the outermost part, and a cooling part 13 filled with liquid nitrogen N is provided inside thereof.
B is provided, and a shield layer 13C compactively filled with the bismuth-based high-temperature superconducting single crystal powder SP is provided in the central portion. Therefore, the bismuth-based high temperature superconducting single crystal powder SP filled in the shield layer 13C is cooled by the cooling unit 13B.
Since it is cooled to the critical temperature or lower by the liquid nitrogen N, the strong magnetism generated from the ground coils 14, 15, the superconducting coil 16 and the like due to the Meissner effect can be prevented from entering the vehicle interior.

[0014]

As described above, according to the present invention, bismuth
After melting the system mixture, quench the melt
A solid state bismuth-based mixture in the solid state
Heat treatment to precipitate a single crystal,
The superconducting single crystal powder obtained by making crystals into powder is used as the heat insulation layer.
A magnetic layer adjacent to the cooling layer filled with liquid nitrogen
-By magnetically filling the hollow part of the shield layer,
A magnetic field with a complicated or large shape can be created because
Even a shielded body can be made lightweight and easy
It becomes possible to realize a sufficient shield effect at low cost.
The effect is that it can be revealed. Further, since the superconducting single crystal powder has extremely low thermal conductivity, a heat insulating effect can be expected.

[Brief description of drawings]

FIG. 1 is a cross-sectional view showing that a magnetic shield method using a superconducting single crystal powder of the present invention is applied to a biological diagnostic apparatus.

FIG. 2 is a sectional view showing that the magnetic shield method using the superconducting single crystal powder of the present invention is applied to a magnetic levitation linear train.

3 is a partial detailed view of FIG. 2. FIG.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Biomedical diagnostic apparatus 6 Magnetic shield part 6A Main body magnetic shield part 6B Door magnetic shield part 7A Vacuum space part 7B Vacuum space part 8A Cooling part 8B Cooling part 9A Shield layer 9B Shield layer SP Bismuth System high temperature superconducting single crystal powder 11 Magnetic levitation type linear train 12 Car body 13 Magnetic shield part 13A Vacuum space part 13B Cooling part 13C Shield layer 14 Ground coil 15 Ground coil 16 Superconducting coil

Claims (1)

[Claims] 1. A heat insulating layer comprising a vacuum space and the heat insulating layer
A cooling layer filled with liquid nitrogen adjacent to the
Laminated with magnetic shield layer cooled by the required shape
Of the magnetic shield layer of the magnetic shield part integrated like a circle
The bismuth-based mixture was melted in the hollow part.
And quenching the melt to a solid state,
The bismuth-based mixture that has become
Crystals were deposited and the single crystals were converted into powders to obtain supercurrent.
By uniformly compacting the conductive single crystal powder,
-The outer peripheral part of the device requiring the magnetic field is magnetized by the magnetic shield part.
Using a superconducting single crystal powder characterized by air shielding
Magnetic shield method.