JPS5932113A - Superconductive magnet apparatus - Google Patents

Abstract

PURPOSE:To curtail operation cycles by independently providing vacuum exhausting apparatus respectively to the irradiation shield and vacuum container on the occasion of forming a superconductive magnet apparatus by surrounding a helium container accommodating a superconductive magnet with a radiation shield internally provided with multilayer temperature insulating material and further by surrounding the entire part with a vacuum casing. CONSTITUTION:A coil 1 obtained by winding a superconductive material is housed in a helium container 2 filled with liquid helium and it is then surrounded by a radiation shield 3. At this time, the internal wall of shield 3 is provided with multilayer temperature insulating material 3b which has a structure of several tens of layers where polyester net is stacked on a thin layer vacuum- depositing aluminum on miler, while the external circumference is wound by a cooling tube 3a which allows liquid nitrogen or low temperature helium gas to flow, thereby forming an individual container 3c. This container is then surrounded by a vacuum container 4 having the heat insulating function by the vacuum condition, and the vacuum exhaustion apparatuses 7 and 6 are provided respectively to the individual container 3c and vacuum container 4. Thereby, the vacuum exhaustion period can be curtailed.

Description

[Detailed description of the invention] Technical field of invention] The present invention relates to a superconducting magnet device.

[Technical Background of the Invention and Problems Therein] A superconducting magnet device has a coil structure (1) by winding four superconducting bodies made of a superconducting filament and a stabilizing material such as copper or aluminum, and storing the coil in a liquid helium container. , kept at a cryogenic temperature below the critical temperature by immersing it in liquid helium. Since the coil becomes superconducting and the electrical resistance of the superconducting filament becomes zero, a large '#+L current can flow and a strong magnetic field can be obtained. For this reason, superconducting magnet devices have become widely used in nuclear fusion, M}ID power generation, etc.

Because superconducting magnets must be kept at extremely low temperatures, they are designed to minimize heat penetration. Tradition. In order to prevent heat intrusion due to conduction, the amount of heat intrusion is reduced by using a material such as a magnet support device having a low thermal conductivity, such as an epoxy resin cylinder.

For convection, place the magnet in a vacuum container and lσ5
By creating a vacuum on the order of ~1σ"3'orr, heat intrusion due to convection (() is prevented.For radiation 1c, a copper plate fitted with a cooling tube through which liquid nitrogen or low-temperature gas helium, called a radiation shield, is installed. A structure equipped with Gζ multilayer insulation is installed between the inner wall of the vacuum vessel and the magnet to suppress heat intrusion due to radiation.

Incidentally, this multilayer insulation material is usually made up of dozens of layers of polyester net or the like overlaid on Mylar or the like with aluminum vapor deposited on top. Therefore, it contains a large amount of moisture in the atmosphere,
It also includes various solvents (eg, acetone, methyl alcohol) used during the manufacturing stage. These are released as multi-fit outgas during vacuum evacuation, and the time required to reach the specified vacuum range is 1.5 to 2 times longer than when there is no multilayer insulation material. This has the disadvantage that the operating cycle of the superconducting magnet device is delayed for a long time, and the ultimate vacuum level is also greatly affected by the outgas release wind, and a vacuum exhaust device that is larger than necessary must be provided in order to achieve a predetermined vacuum level.

[Purpose of the invention]

An object of the present invention is to obtain a superconducting magnet device which has been made to solve the above-mentioned drawbacks and can shorten the operating cycle.

[Summary of the Invention] To achieve the objects stated in the following, the superconducting magnet device of the present invention includes a superconducting magnet device, a vacuum container for vacuum insulating the superconducting magnet, and a multi-rvj for preventing radiation heat from the vacuum container. It is characterized by consisting of a radiation shield provided with heat insulating paulownia wood, and a single container for storing a large amount of heat insulating material for the radiation shield.

[Embodiments of the invention]

An embodiment of the present invention will be described below with reference to the drawings.

In Figure 1, (fl) is a coil wound with four superconducting bodies, (2) is a helium container containing coil fl) and liquid helium, and (3) is a radiation shield cooled with liquid nitrogen or low-temperature gas helium. , (4) is a vacuum container that vacuum-insulates the helium container (2), and (5) is a support device for the helium container (2). Figure 2 shows a detailed diagram of the radiation shield (3). (3a) is a cooling pipe through which liquid nitrogen or low-temperature gas helium flows, (311) is a multilayer insulation material made of dozens of layers of 6t polyester net made of evaporated aluminum on Mylar, etc., and (3c) is a multilayer insulation material ( 3
b) is a single container made of multilayer heat insulating material made of copper or stainless steel, and is in contact with the cooling pipe (3a) through one connection, such as by brazing. (6) is a vacuum evacuation device that evacuates the inside of the vacuum container (1);

Normal operation of a superconducting magnet device is carried out in a vacuum chamber 11).
The interior is evacuated using a vacuum evacuation device (6), but since the multi-layer insulation layer (31) is located in a separate container, the specified vacuum is achieved in a short time without being affected by Daiken's outgas. range (16! to 10'' Torr range), resulting in an improved ultimate vacuum degree. At the same time, the inside of the single multilayer insulation material container (3C) is also evacuated using the vacuum evacuation device (7), but because the volume is small, even if a large amount of outgas is released, it takes only a short time, and the overall evacuation time is shortened. be converted into Further, even during disassembly and inspection of the magnet, the interior of the multilayer insulation material single container (3C) can be kept evacuated, making it possible to shorten the entire operation cycle.

FIG. 3 shows another embodiment, in which the cooling pipe (3a) is installed by VC brazing or the like on the inner surface of the multilayer heat insulating closed container (3b). With such a structure, even if a leak occurs from a joint of the cooling pipe, it is possible to avoid a situation in which the degree of vacuum in the vacuum container decreases.

〔Effect of the invention〕

As described above, the present invention has the effect of shortening the evacuation time and shortening the overall operation cycle by storing the multilayer insulation material in a single container and providing a separate evacuation device. .

[Brief explanation of drawings]

FIG. 1 is a vertical cross-sectional view showing one embodiment of the superconducting magnet device of the present invention, FIG. 2 is a partial detailed vertical cross-sectional view of FIG. 1, and FIG.
The figure is a partially detailed longitudinal section showing another embodiment of the invention.

Claims (1)

[Scope of Claims] (υ A superconducting magnet, a vacuum container for vacuum insulating the superconducting magnet, a radiation shield provided with a multilayer insulation material to prevent radiation heat from the vacuum container, and a multilayer insulation of the radiation shield) (2) A patented device characterized in that a superconducting magnet device is provided with a separate vacuum evacuation device for evacuating the inside of a single container containing a multilayer insulation material.