JPH07122877A - Ventilation structure of magnetic shield room - Google Patents

Abstract

PURPOSE:To perform a sufficient ventilation and to reduce a magnetic leakage by a method wherein through holes are made individually in mutually deviated positions in face parts which constitute individual layers for a multilayer structure made of a high-permeability alloy plate and a ventilation duct composed of a magnetic insulating material is inserted into the through holes. CONSTITUTION:A ventilation duct 22 which permits ventilation between a space 18 and the outside is arranged and installed so as to be tilted up and down passing a wall face at the sidewall face part of a magnetic shield room 10. That is to say, a first through hole 24 is made in a required position at the sidewall face part of an outside chamber 12, a second through hole 26 is made in the sidewall face part in an intermediate chamber 13 in a position deviated to the upper part with reference to the first through hole 24, and, in addition, a third through hole 28 is made on the sidewall face part in an inside chamber 16 in a position which is deviated to the upper part with reference to the second through hole 26. Then, the ventilation duct 22 is fitted to, and inserted into, the three through holes 24, 26, 28 in common in such a way that the outside communicates with the space 18.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a ventilation structure for a magnetically shielded room, and more particularly to a structure for arranging a ventilation duct used in a magnetically shielded room for blocking the intrusion of geomagnetism.

[0002]

2. Description of the Related Art For example, when measuring and detecting a magnetic field weaker than the earth's magnetism such as an electroencephalogram or a CT scanner, it is necessary to block the magnetic influence from the outside, and a magnetic shield room is suitable as a means for this purpose. Is used for. This magnetically shielded room is known to have multiple layers of alloy plates made of high-permeability materials such as permalloy and silicon steel plates, and is designed to prevent external magnetic fields from entering the room where various measuring devices are housed. It is designed to be blocked by multiple layers.

In the magnetically shielded room, it is indispensable to dispose a ventilation duct for ventilation inside the room. In this case, if the opening of the ventilation duct is set large in order to provide sufficient ventilation in the room, the magnetic shielding effect is reduced, and if the opening is made small, sufficient ventilation cannot be achieved. Therefore, conventionally, a honeycomb structure formed by bending and assembling a high-permeability alloy plate having a magnetic absorption function has been used as a ventilation duct to provide sufficient ventilation and a magnetic shielding effect.

[0004]

Since the above-mentioned ventilation duct is made of a high-permeability alloy plate, when the magnetism transmitted from the outside cannot be absorbed, the magnetism leaks into the room through the duct. However, there is a drawback that the desired magnetic shielding effect cannot be expected. Further, it is pointed out that the processing and assembling of the honeycomb structure is complicated and the number of steps is large, resulting in a high manufacturing cost. Further, there is a drawback that maintenance is troublesome.

[0005]

SUMMARY OF THE INVENTION In view of the problems inherent in the above-mentioned prior art, the present invention has been proposed to suitably solve the problems, and a magnetic shield room having a simple structure with less magnetic leakage. It is intended to provide a ventilation structure for.

[0006]

In order to overcome the above-mentioned problems and achieve the intended object, the present invention provides a ventilation structure for ventilating the inside and the outside of a magnetically shielded room of a multi-layer structure made of a high-permeability alloy plate. Further, it is characterized in that through holes are formed in the surface portions forming the respective layers at positions deviated from each other, and ventilation ducts made of a magnetic insulating material are inserted into these through holes.

[0007]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Next, a ventilation structure for a magnetically shielded room according to the present invention will be described below with reference to the accompanying drawings with reference to preferred embodiments.

FIG. 1 is a schematic vertical sectional front view of a magnetic shield room according to an embodiment, in which the room 10 has a floor FL.
An external chamber 12 installed in the intermediate chamber 13 and an intermediate chamber 13 housed in the external chamber 12 with a plurality of insulating materials 14 made of wood or the like separated by a required distance. A three-layer structure is formed from the internal chamber 16 that is housed with the material 14 separated by a required distance. The external chamber 12, the intermediate chamber 13, and the internal chamber 16 each have a similar shape formed in a cubic (hexahedral) shape consisting of front, rear, left, and right wall surfaces, a ceiling surface portion, and a floor surface portion. measuring equipment
(Not shown) is accommodated. Each of the outer chamber 12, the intermediate chamber 13, and the inner chamber 16 is a cube formed by combining rectangular plate members 20 made of a high magnetic permeability alloy. As the high magnetic permeability alloy, a soft magnetic material such as Fe-45Ni (PB permalloy),
80Ni-Mo-Fe, 78Ni-Mo-Cu-Fe
(PC permalloy) or 70Ni-10Cu-12Mn
-Fe (Daido symbol PC-X) is preferably used. Further, the thickness dimension of the plate member 20 is set to 2 mm or more,
The space between the chambers 12, 13 and 16 is set to 250 mm or more. As a result, the space 1 in the inner chamber 16
The central magnetic field of 8 is 1 / of the earth's magnetism (0.46 oersted)
It can be set to 1000 (60 dB), and an extremely high magnetic shielding effect is achieved. The insulating material 14 is not limited to wood, but a non-magnetic material can be preferably used.

As shown in FIG. 1, a ventilation duct 22 that allows ventilation between the space 18 and the outside penetrates the side wall surface of the magnetically shielded room 10 vertically with respect to the wall surface. It is arranged. That is, as clearly shown in FIG. 2, a first through hole 24 is formed at a required position in the side wall surface portion of the outer chamber 12, and the first through hole 2 is formed.
4, a second through hole 26 is formed in the side wall surface portion of the intermediate chamber 13 at a position deviated upward from the second through hole 2
A third through hole 28 is formed in a side wall surface portion of the inner chamber 16 at a position deviated upward with respect to 6. The ventilation duct 22 is commonly inserted into the three through holes 24, 26, 28 to connect the outside and the space 18. The inclination angle of the ventilation duct 22 with respect to the wall surface portion is set in the range of 20 ° to 70 °.

The ventilation duct 22 is made of a magnetic insulating material such as wood, synthetic wood or resin.
It is configured so that the external magnetism does not enter the inside along the line 2. In the ventilation duct 22 made of a magnetic insulating material, since the material itself does not have a function of absorbing magnetism, external magnetism may enter the inside through the through holes 24, 26 and 28. However, in the embodiment, as described above,
Since the positions of the through holes 24, 26, 28 are deviated from each other, the magnetism leaking inside from the first through hole 24 is
The side wall surface of the intermediate chamber 13 facing the position facing the through hole 24 is prevented from being absorbed and shielded from entering the inside through the second through hole 26. Further, even if the magnetism that cannot be completely absorbed in the intermediate chamber 13 leaks to the inside from the second through hole 26,
The magnet 1 is located in the inner chamber 1 facing the second through hole 26.
The side wall surface portion 6 is prevented from being absorbed and shielded from entering the space 18 through the third through hole 28. That is, the magnetism from the outside is absorbed and shielded by the side wall surface portion around the ventilation duct 22, and the central magnetic field of the space 18 can be maintained at the level described above. Further, since the outside opening of the ventilation duct 22 is directed downward, it is possible to prevent dust and the like from entering from the outside.

[0011]

[Regarding another embodiment] FIG. 3 shows another embodiment of the ventilation structure in which a ventilation duct 22 is provided at a corner portion of the magnetic shield room 10. In this embodiment, the first through hole 24, the second through hole 26, and the third through hole 28 are formed at positions that are offset from each other in the horizontal direction with respect to the wall surface portion. It is configured so that external magnetism does not leak inside via 24, 26 and 28. In another embodiment shown in FIG. 4, the ventilation duct 22 is formed in a V shape, and the three through holes 24, 26, 2 are formed in accordance with the shape.
8 are provided at positions offset from each other in the horizontal direction. Further, in another embodiment shown in FIG. 5, the ventilation duct 22 is formed in a substantially stepped shape, and the three through holes 24, 26, 28 are arranged at positions displaced from each other in the horizontal direction according to the shape. Has been drilled. In addition, in another embodiment shown in FIGS. 3, 4, and 5, the three through holes 24, 26, and 28 may be formed so as to be displaced vertically from each other.

FIG. 6 is a cross-sectional plan view of a magnetic shield room showing still another embodiment, in which a first through hole 24 is formed in the right wall surface portion of the outer chamber 12, and the front wall surface of the intermediate chamber 13 is formed. A second through hole 26 is formed in the portion (the lower side in the drawing), and a third through hole 28 is further formed in the left wall surface portion of the internal chamber 16 so that the space between the through holes 24, 26, 28 is large. A ventilation duct 22 is provided in the. In this embodiment, each through hole 24, 26,
Since the position of 28 is greatly deviated, each through hole 24, 2
Magnetic leakage between 6 and 28 can be completely prevented, and an extremely high magnetic shielding effect can be maintained. Since the ventilation passage is long in this example, it is recommended to perform forced ventilation from outside with a fan motor or the like.

Further, as shown in FIG. 7, in the outer chamber 12,
The external chamber 1 is continuous with the end of the ventilation duct 22.
By forming the protrusion 23 in which the second plate member is protruded outward by a required length, it is possible to suppress the intrusion of magnetism from the opening. Further, as shown in FIG. 8, a shielding plate 30 having a plurality of through holes 30a made of a magnetic insulating material or a high-permeability alloy is inserted in the ventilation duct 22 or the shielding plate 30 is inserted. Through holes 24, 26,
It may be inserted into 28 and communicated by a duct between them. The shield plate 30 can prevent dust from entering, and the shield plate 30 made of a high-permeability alloy plate improves the magnetic shield effect.

Although the magnetic shield room having a triple structure has been illustrated in the embodiment, the ventilation structure of the present invention can be preferably applied to a magnetic shield room having a double structure or a quadruple structure or more. Further, the shape of each room of the shield room is not limited to a cube, but may be a rectangular parallelepiped or other polygonal shape. Further, the position of the ventilation duct provided in the magnetic shield room is not limited to the wall surface portion but may be the ceiling surface portion or the floor surface portion. When the ventilation duct is installed on the floor surface, it is necessary to provide a required gap between the external chamber and the installation floor surface.

[0015]

As described above, according to the ventilation structure of the magnetic shield room according to the present invention, sufficient ventilation can be performed and magnetic leakage can be reduced with an extremely simple structure. In addition, the number of man-hours for designing, molding, assembling, and constructing is small, and the assembly can be accurately performed in a short time and the cost can be reduced. Furthermore, maintenance of the ventilation duct is easy.

[Brief description of drawings]

FIG. 1 is a schematic vertical sectional front view of a magnetic shield room adopting a ventilation structure according to a preferred embodiment of the present invention.

FIG. 2 is a schematic vertical cross-sectional front view of essential parts showing an enlarged view of the ventilation structure shown in FIG.

FIG. 3 shows another embodiment of the ventilation structure according to the present invention, and is a schematic cross-sectional plan view of essential parts showing a ventilation duct provided at a corner portion.

FIG. 4 shows another embodiment of the ventilation structure according to the present invention, and is a schematic cross-sectional plan view of essential parts showing a V-shaped ventilation duct.

FIG. 5 shows another embodiment of the ventilation structure according to the present invention, and is a schematic cross-sectional plan view of essential parts showing a ventilation duct formed in a substantially stepped shape.

FIG. 6 is a schematic cross-sectional plan view of a magnetic shield room adopting a ventilation structure according to another embodiment of the present invention.

FIG. 7 is a schematic sectional view showing a ventilation structure according to still another embodiment of the present invention, in which an end portion of a ventilation duct is projected outward from an external chamber.

FIG. 8 is a schematic perspective view of a main part showing a cross section of a state in which a shielding plate is inserted in the ventilation duct according to the embodiment.

[Explanation of symbols]

 10 Magnetic Shield Room 12 External Room 13 Intermediate Room 16 Internal Room 22 Ventilation Duct 24 First Through Hole 26 Second Through Hole 28 Third Through Hole

Claims (2)

[Claims] 1. A ventilation structure for ventilating the interior and exterior of a magnetically shielded room having a multi-layered structure made of a high-permeability alloy plate, wherein through holes are provided at positions deviated from each other in a surface portion forming each layer. A ventilation structure for a magnetically shielded room, which is provided with a ventilation duct made of a magnetic insulating material inserted through these holes. 2. The ventilation duct is 20 ° with respect to a surface portion.
The ventilation structure for a magnetically shielded room according to claim 1, wherein the ventilation structure is arranged so as to be inclined in the range of 70 °.