JPS6112720Y2 - - Google Patents

Description

[Detailed explanation of the idea] The present invention relates to a magnetic shielding device.

Conventional magnetic shielding devices are used to shield experimental equipment and instrumentation equipment from weak magnetic fields such as the earth's magnetism, and are made of high permeability materials such as permalloy. In recent years, with the development of nuclear fusion devices that use strong magnetic fields, large magnetic shielding devices that can withstand strong magnetic fields of 200 to 1000 Oe have become necessary to protect peripheral equipment and measurement equipment. For this reason, in order to prevent the saturation of the magnetic material and obtain a high shielding effect, the outer cylinder has a high saturation magnetic flux density, e.g.
Electromagnetic soft iron such as JISC2503 electromagnetic soft iron rod or JISC2504 electromagnetic soft iron plate must be used, and a magnetic material with high magnetic flux must be used for the inner cylinder. However, the thickness of the electromagnetic soft iron of the outer cylinder reaches 20 to 50 mm. Although it is technically possible to construct an outer cylinder using such a thick plate, (1) it is difficult to heat the thick plate evenly, so the effect of magnetic annealing, which is performed to improve magnetic properties, is limited; few. (2) Depending on the size, new magnetic annealing equipment may need to be manufactured, resulting in high costs. (3) The material had to be specially ordered and was expensive.

This invention was developed in view of the above drawbacks, and instead of using thick plates, the outer cylinder is manufactured by laminating and attaching thin plates of electromagnetic soft iron to a support frame as a strength member, so that the strength is equivalent. , the magnetic properties are improved,
An object of the present invention is to provide a magnetic shielding device that is easy to manufacture.

An embodiment of the present invention shown in the drawings will be described below. In the figure, 1 is a support frame composed of square bars;
2 is a connecting member made of electromagnetic soft iron which is fixed to the corner of the support frame 1 and provided with a step 2a, and 3 is a connecting member made of electromagnetic soft iron having a thickness of, for example, 5 to 15 mm and stacked in different steps between the steps 2a of the connecting member 2. The outer cylinder 3 is a cylindrical outer cylinder and is fixed to the support frame 1 with bolts. Reference numeral 4 denotes an inner cylinder made of a high magnetic permeability material such as permalloy, which is disposed at intervals inside the outer cylinder 3, and 5 is a support member made of a non-magnetic material that supports the inner cylinder 4 from the support frame 1.

Next, the action will be explained. The outer cylinder 3 is made of thin electromagnetic soft iron plates 3a laminated to the required thickness, so manufacturing costs are low because commercially available thin electromagnetic iron plates can be used, and magnetic annealing can be performed on each material. Since each material is thin, it can be heated evenly and the improvements in magnetic annealing can be fully utilized, resulting in high magnetic resistance. Since the connecting member 2 is used at each corner, it can be processed with high precision without the need for plate bending, and since it is stepped, the contact area of each electromagnetic soft iron plate 3a is wide and the magnetic resistance is small. Therefore, the magnetic resistance effect is large. In addition, since the electromagnetic soft iron plate 3a and the connection part 2 are fixed to the support frame 1 with bolts, the stress generated in the structure is small, so it is only necessary to anneal each piece individually, and the annealing after assembly is not necessary. No need for a large annealing furnace.

As described above, according to the present invention, the outer cylinder of the magnetic shielding device is formed by laminating electromagnetic soft iron plates on the outside of the support frame.
The edges are connected and fixed using stepped electromagnetic soft iron connecting members, and the inner cylinder is placed with a space inside the outer cylinder, so the strength is the same as the conventional one, and it is less susceptible to magnetism. It is highly effective, has good manufacturing precision, and because the electromagnetic soft iron plate is thin, it is easy to manufacture and is therefore inexpensive.
This has effects such as being able to reduce the cost of the device.

[Brief explanation of the drawing]

The figure is a longitudinal sectional view showing an embodiment of the magnetic shielding device of the present invention. 1...Support frame, 2...Connection member, 3...Outer cylinder,
3a...Electromagnetic soft iron plate, 4...Inner cylinder, 5...Supporting member.

Claims (1)

[Scope of utility model registration request] A support frame, an outer cylinder whose corners are connected and fixed by laminated electromagnetic soft iron plates on the outside of the support frame with stepped electromagnetic soft iron connecting members, and a space provided inside the outer cylinder. A magnetic shielding device consisting of an inner cylinder made of high magnetic permeability material.