JPS6366043B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a cryostat for a superconducting magnet that generates a magnetic field in a hollow room temperature space and has low heat loss.

[Prior Art] Conventionally, this type of cryostat has often been of a vertical cylindrical type that is used in a suspended manner with the upper lid as a fulcrum.

[Problem to be solved by the invention]

However, in recent years, it has become desirable to provide a room-temperature space horizontally, and in this case a horizontal cylindrical type cryostat is used, but such equipment has the drawbacks of a complex structure and large heat loss. .

SUMMARY OF THE INVENTION An object of the present invention is to provide a horizontal cylindrical cryostat that has a simple structure, is easy to assemble, and has low heat loss.

[Means to solve the problem]

The features of the present invention include a liquid helium container 3 containing a superconducting coil 1 and liquid helium 2, heat shield plates 4 and 7 surrounding the outside of the superconducting coil 1, a liquid nitrogen container 5 surrounding the outside of the container, and a liquid nitrogen container 5 wrapped around the outside of the container. In a cryostat whose main components are a multilayer insulation material 8 and a vacuum container 9 surrounding the outside and forming a hollow normal temperature space 17, a plurality of protrusions 13 are provided on the side wall of the liquid helium container 3. established,
Between each projection 13 and a support member 14 provided on the side wall of the liquid nitrogen container 5 corresponding to the projection, multiple thin cylinders with low thermal conductivity are connected alternately at their ends and center. A heat-resistant plate 43 is placed in the middle between them.
The liquid nitrogen container is supported within the vacuum container by a rod-shaped member having low thermal conductivity. Note that the numbers in parentheses in the above text indicate the corresponding symbols in FIG. 1 of the representative illustrative drawing, but the shapes etc. shown in the drawings are merely illustrative.

[Effect]

With the above configuration, the liquid helium container and the like are supported only on the side surfaces of the cylindrical body, so the structure is simple and assembly is easy. The support structure can transmit sufficient load while keeping the amount of heat transferred low due to the thin multi-layered cylinders with low thermal conductivity and the intermediate cooling ability of the heat shielding plate 43.

〔Example〕

Hereinafter, the content of the present invention will be explained according to Examples.

FIG. 1 is a partial cross-sectional view of a cryostat having a horizontal normal temperature space according to an embodiment of the present invention, and FIGS. 2 and 3 are respectively partial cross-sectional perspective views of this embodiment. In Figure 2, one end of the vacuum container 9 is cut at the multilayer insulation material 8 side (near the end surface of the liquid nitrogen container 5), the other end is also cut halfway, and a part of the side surface of the vacuum container 9 is removed to explain the internal structure. This is a diagram.
Moreover, FIG. 3 is a diagram in which the end surface 91 of FIG. 1 is removed and the end portion of the multilayer heat insulating material 8 is removed.

The superconducting magnet 1 is housed in a liquid helium container 3, and liquid helium 2, which is a coolant, is placed in the liquid helium container 3 so as to immerse the superconducting magnet 1. This liquid helium container 3
is formed in a cylindrical shape concentrically with the cylinder 10,
The superconducting magnet 1 is arranged in a ring shape along the inner surface of the liquid helium container 3.

The periphery of the liquid helium container 3 is the first one with a gap.
A heating shield plate 4 covers the heating shield, and a second heating shield plate 7 covers the surrounding area. A liquid nitrogen container 5 is formed on the outside of the second heat shielding plate 7 and is thermally connected thereto, and stores liquid nitrogen 6 therein. Further, the outside thereof is wrapped with a multilayer insulation material 8. This multilayer insulation material is made by alternately stacking aluminum or a polymer film on which aluminum is deposited and a poor thermal conductor. 9 is a vacuum container at room temperature, and 10 is a cylinder forming a hollow room temperature space 10'. 11 is a port for introducing/inputting current to liquid helium or superconducting magnet; 12
is the liquid nitrogen inlet/outlet port. 13 is a cylindrical projection provided on the liquid helium container 3; 14
is a support member made of a hollow cylinder provided on the side wall of the liquid nitrogen container 5. Two to three protrusions 13 are provided on each end surface of the liquid helium container 3, and a hollow cylinder 14 covers each protrusion 13.

The hollow cylinder 14 is thermally connected to the heat shield plate 7, and the hollow cylinder 14 is further covered with a multilayer heat insulating material 8. Reference numeral 15 denotes a support structure in which multiple thin-walled cylinders are alternately connected at both ends and the center, and a heat shield plate 43 that is thermally connected to the first heat shield plate 4 is inserted in the middle part. Carbon fiber reinforced resin or glass fiber reinforced resin is suitable for this thin cylinder. At the end of the heat shield plate 43, the heat shield plate 41 serves as a lid, and at the end of the heat shield plate 7, the heat shield plate 71 serves as a lid. In this way, the heat shielding plates are arranged so as to double cover each cylindrical projection 13, and for this reason, the ends of each heat shield plate 4, 7 are cut along each projection 13. ing. Further, both ends of the vacuum container 9 are closed with lids 91. Incidentally, the vacuum container 9 is naturally also a circular tube 10.
It is located like a donut around the . The hollow cylinder 14 and the vacuum container 9 are connected by a rod 16 having low thermal conductivity or the like. The inside 17 of the vacuum container 9 is
The pressure is below 10 ^-5 Torr.

The relationship between the rod 16 and the hollow cylinder 14 is shown in cross-sectional views in FIGS. 4 and 5. 5 is a liquid nitrogen container containing a liquid helium container and a first heating shield, 9 is a vacuum container, 14 is a hollow cylinder provided on the side wall of the liquid nitrogen container, and 16 is a rod that supports this in the vacuum container. . FIG. 4 shows two hollow cylinders 14 on one side wall,
In the case where there are four pieces on the entire surface (both ends), FIG. 5 shows the case where there are three pieces on one side wall and six pieces on the whole (both ends). stick 1
The arrangement of 6 may be changed as appropriate. Moreover, the rod 23 may be any rod-shaped member, such as a hollow cylinder.

Next, the assembly procedure will be explained. First, the superconducting magnet 1 is assembled into a cylindrical liquid helium container 3. Double heat shielding plates 4 and 7 (both cylindrical) are arranged so that a gap is formed around this (both inside and outside), and the ends of each and the container 3 are connected to the support structure 15. Fix it. Next, the heating plate 41,
After covering with a lid 71, the multi-layer insulation material 8 covers the surroundings thereof. Note that the ports 11 and 12 are not attached at this stage. The internal structure thus assembled is housed and positioned in the cylinder of the vacuum container 9, and then the relationship between the hollow cylinder 14 and the vacuum container 9 is fixed using the rods 16. Next, the ports 11 and 12 are inserted through the two holes above the vacuum container 9 and welded. Finally, both ends of the vacuum container 9 are closed with lids 91, and the cylinder 10 is also inserted to complete the assembly.

In such a configuration, the liquid helium container 3 and the first heat shielding plate 4 are supported only on the side surfaces of the cylindrical body, so the structure is simple and assembly is easy. Also,
Although the implementation of multilayer insulation material 8 is time-consuming,
The liquid nitrogen container has already been assembled, so
Just wrap it around it. This is inserted into a cylindrical vacuum container 9, the rods 16 are stretched with both end faces open, and the relative positions of the two are determined. Finally, by placing the lid 91 on the end face and inserting the cylinder 10, assembly is easily completed. The thermal conductivity of the fiber-reinforced resin forming the thin-walled multi-cylinder is considerably lower than that of metal, and the support structure 15 consisting of the thin-walled multi-cylinder is folded back to ensure a long conduction distance.
Since the 50K heating plate 4 performs intermediate cooling and absorbs the radiant heat from the high temperature cylinder on the outside, the amount of heat transferred can be suppressed to several milliwatts while transmitting sufficient load. If something penetrates the multilayer heat insulating material 8, the heat insulating performance will deteriorate, but if the rod-shaped member has a small cross-sectional area, the effect can be kept to a minimum.

FIG. 6 shows another embodiment of the present invention.
Only the periphery of the support structure 15 in the figure is shown. It becomes necessary to transport the cryostat before installation. In order to ensure heat insulation performance, the cross-sectional area of the support structure 15 and the rods 16 is suppressed as much as possible, so sufficient safety is not necessarily expected in terms of strength. Therefore, during transportation, the end flange of the vacuum container 9 is removed to expose the cylindrical protrusion 13. For example, a screw hole or the like is opened in the cylindrical projection 13, and the cylindrical projection 13 is firmly fixed directly from the end face of the vacuum container 9 with a strength member 30 such as a thick screw. After transportation, when installing, open the end face of the vacuum container 9 and insert the heat shield plate 41.
and 42 and the multilayer insulation material 8 are restored to their normal state.

In this way, it is possible to create a support method that can withstand transportation with just a few changes to the insulation part.

〔Effect of the invention〕

As described above, according to the present invention, a cryostat with a simple structure, easy assembly, and low heat loss can be obtained. Another great advantage is that it can be easily supported for transportation using a support structure.

[Brief explanation of drawings]

FIG. 1 is a side sectional view showing one embodiment of the present invention, FIGS. 2 and 3 are partial sectional perspective views of the embodiment device of FIG. 1, and FIGS. 4 and 5 are respectively FIG. 6 is a schematic front cross-sectional view showing one embodiment, and FIG. 6 is a partial side sectional view showing another embodiment of the present invention. 3... Liquid helium container, 4... First heating plate, 5, 20... Liquid nitrogen container, 8... Multilayer insulation material, 9, 21... Vacuum container, 13... Cylindrical protrusion, 14, 22... Hollow cylinder, 15... Support structure, 16, 23... Rod, 30... Strength member.

Claims (1)

[Claims] 1. A liquid helium container containing a superconducting coil and liquid helium, a heat shielding plate surrounding the outside, a liquid nitrogen container surrounding the outside, a multilayer insulation material wrapped around the outside of the container, and a hollow space surrounding the outside. In a cryostat whose main component is a vacuum container forming a normal temperature space, a plurality of protrusions are provided on the side wall of the liquid helium container,
A support structure is provided between each of the protrusions and a support member provided on the side wall of the liquid nitrogen container corresponding to the protrusion, and each of the support structures has multiple support structures between the protrusion and the support member. Thin cylinders with low thermal conductivity are alternately connected at their ends and central portions, and a heat shield plate is attached to the middle portion, and the liquid nitrogen container is supported within the vacuum container by a rod-shaped member with low thermal conductivity. A cryostat featuring: