JPS5915086Y2 - Load support device for cryogenic equipment - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a support device for a cryogenic container of a superconducting device 1 cooled by a cryogenic device, such as liquid helium.

Typically, cryogenic equipment includes a vacuum insulation tank and a cryogenic container that houses a cryogenic agent.

Among these, the vacuum insulation tank is placed at room temperature on the atmosphere side, and the cryogenic container is cooled and maintained at a cryogenic temperature within the vacuum insulation tank with a high degree of thermal insulation.

Particularly in superconducting equipment, since liquid helium (4,2'K) is used as a cryogenic agent, thermal insulation between the vacuum insulation layer and the vacuum insulation layer is a major factor that influences the performance of the superconducting equipment.

For this reason, in superconducting equipment, it is common to provide a radiation shield or provide thermal insulation such as multilayer insulation between the vacuum insulation tank and the cryogenic container.

- The support device that supports the weight or electromagnetic force of the front cryogenic container should minimize heat intrusion into the cryogenic container.
It is also necessary to use a structure, material, etc. that is mechanically strong against the weight or load.

In addition, as cryogenic equipment becomes larger, the weight of the cryogenic container becomes extremely large, the amount of thermal contraction of the cryogenic container increases in proportion to the size of the equipment, and there are problems with superconducting equipment. In other words, the load due to electromagnetic force increases, etc.
Problems arise when designing a support device.

The present invention takes these problems into consideration and provides a support device that has a simple structure, little heat intrusion into the cryogenic container, and sufficient mechanical strength.

By using the support device of the present invention, it is possible to support a cryogenic container of a large cryogenic device with a simple structure, a small amount of heat penetration, and sufficient mechanical strength.

An embodiment in which the present invention is applied to a superconducting magnet device will be described below.

In FIG. 1, 1 is a vacuum insulation tank, 2 is a cryogenic container stored in the vacuum insulation tank 1, 3 and 4 are superconducting magnets and liquid helium, respectively, stored in the cryogenic container 2, and 5 is a superconducting magnet. Ports 6 for the current inlet and outlet to 3, the inlet for liquid helium 4 and the outlet for evaporated helium gas are provided between the vacuum insulation chamber 1 and the cryogenic container 2 to shield radiation heat between them. It is a radiation shield.

7a and 7b are support devices that support the cryogenic container 2 from the vacuum insulation tank 1, and 7a mainly supports the weight of the cryogenic container 2 (including the weight of the superconducting magnet 3 and liquid helium 4).
and a support device for supporting vertical loads, and 7b is a support device for supporting horizontal loads mainly acting on the cryogenic container 2.

FIG. 2 shows the detailed structure of 7a and 7b.

In FIG. 2, numerals 1, 2, and 5 are a vacuum insulation tank, a cryogenic container, and a radiation shield, respectively, as in FIG. 1.

71 is a material that exhibits a low coefficient of friction even in vacuum, such as a combination of Teflon with glass fiber or copper powder, a polyamide resin with a certain proportion of copper or other metals added,
Alternatively, a bearing material made of a metal material such as nickel added with tin, aluminum, etc. is brought into surface contact with the cryogenic container 2.

Reference numeral 72 denotes a support rod made of a material with low thermal conductivity and relatively mechanical strength even at extremely low temperatures, such as a glass epoxy laminated frame. One side is fixed to the bearing material 71 by adhesive or the like, and the other end is a tapered flange. 73 and mounting bolt 7
4, it is firmly fixed to the vacuum insulation layer 1.

FIG. 3 shows a support device designed to maintain the horizontal position of the cryogenic container 2, and is particularly effective when used as the support device 76.

In FIG. 3, 1, 2, 5.71 and 72 are similar to those in FIG. 2, so detailed explanations will be omitted.

Reference numeral 75 is a heat shrinkage absorbing spring that can follow the heat shrinkage of the cryogenic container 2 and the support rod 72 and has sufficient strength against horizontal loads, and is composed of a regular spring.

Reference numeral 76 is a flange fitting for applying preload to the heat-shrinkable spring 75, supporting the support rod 72, and providing a vacuum seal, and is fixed to the vacuum insulation tank 1 with a mounting bolt 78 via a gasket 77.

Usually, a cryogenic device assembled at room temperature (approximately 300'K) is operated by injecting liquid helium 4 into a cryogenic container 2.

At this time, the cryogenic container 2 changes from room temperature to liquid helium temperature (
Since the temperature changes to about 4.2 y), thermal contraction occurs accordingly.

The amount of heat shrinkage is approximately 3 mm per meter in stainless steel, for example.

However, since the vacuum insulation tank 1 remains at room temperature, the cryogenic container 2 moves horizontally with respect to the support device 7a.
7b, it moves in the vertical direction.

Arrows 8 in FIGS. 2 and 3 indicate the direction of movement.

On the other hand, since the load is in the direction of the arrow 9, the support rod 72 receives a lateral load proportional to the product of the friction coefficient in the contact diagram between the cryogenic container 2 and the bearing material 71 and the load on the contact surface. .

This lateral load causes a bending moment to act on the support rod 72.
The maximum bending stress occurs at the joint surface with the flange 73.

In a vacuum, the coefficient of friction is about 10 times larger than in the atmosphere.

However, according to the configuration of the present invention, since a low friction coefficient material is used for the bearing material 71, the applied lateral load can be reduced to a small value, and therefore the maximum bending stress is also reduced, so the bending strength is reduced. Even a support rod 72 made of a relatively weak material with low thermal conductivity can be used satisfactorily.

On the other hand, the amount of heat Q conducted from the vacuum insulation tank 1 to the cryogenic container 2
are the thermal conductivity, cross-sectional area and length of the support rod 72, respectively.
, A, and l, vacuum insulation tank 1 and cryogenic container 2
The temperature difference 7t is expressed as Q-λ·4·, dt.

For example, since the thermal conductivity λ of a glass epoxy laminate frame is about -00 lower than that of stainless steel, the amount of heat Q conducted can be made very small.

This means that the evaporation of liquid helium 4 can be reduced, making it possible to improve the performance of the cryogenic device.

Furthermore, even when the plate cryogenic container weight and electromagnetic force load are large, the bearing material 71 is in surface contact and can receive a large load, while the support rod 72 is resistant to compressive loads. Since it is a strong material, it can be used with high loads.

Next, a case will be described in which a support device having the structure shown in FIG. 3 is used in place of the support device 7b in FIG. 1.

As mentioned above, when the cryogenic container 2 is cooled to liquid helium temperature, it contracts at a rate of about 3 mm/1 m.

This contraction will occur horizontally and vertically.

On the other hand, since one end of the support device 7b reaches the temperature of liquid helium, thermal contraction occurs.

The support device shown in FIG. 3 is capable of supporting the position of the cryogenic container 2 even if there is thermal contraction of both.

In FIG. 3, a preload is applied to the heat shrinkage absorbing spring 75 by a flange fitting 76 during assembly.

As the cryogenic container 27 is cooled, it thermally contracts and moves in the directions of arrows 8 and 9.

The movement in the direction of the arrow 8 is absorbed by sliding between the bearing material 71 as described above.

For movement in the direction of arrow 9, the heat storage absorption spring 75
Deforms elastically.

Therefore, there is no gap between the cryogenic container 2 and the support device, and the center of the cryogenic container 2 is always constant and does not move.

This is very effective because it allows the magnetic field generated by the superconducting magnet 3 to be placed at a fixed position with high precision, as in a superconducting device.

Further, horizontal loads from the direction of arrow 9 can be supported if the heat-shrinkable absorbing spring 75 is designed to withstand the loads.

The effects of the amount of heat intrusion and the load resistance are the same as described above.

The present invention is intended to reduce the lateral load of the support device due to heat shrinkage by incorporating a bearing material made of a material with a low coefficient of friction, and to provide a support device that can withstand high loads and has low heat conduction. There are no restrictions regarding the location of materials.

That is, it is also effective when the bearing material 2 is brought into contact with the vacuum insulation tank 1 side shown in FIG. 2 and the flange 73 and mounting bolts 74 are placed on the cryogenic container 2 side.

Furthermore, there are no restrictions on the shape or attachment method of the bearing material 71.

As explained above, the present invention has the following effects.

(a) Since the bearing material made of a material with a low coefficient of friction is inserted even in a vacuum, it is possible to use a material with relatively low bending strength and low thermal conductivity for the support rod, so there is little heat intrusion into the cryogenic part. can.

(b) By inserting the bearing material, movement of the cryogenic container due to thermal contraction in a direction perpendicular to the support device can be easily absorbed, and a support device with a simple structure, easy to manufacture, and low cost can be provided.

(C) Since the bearing material receives the load through surface contact, it can withstand high loads.

(d) Since a heat-shrinkable absorbing spring is inserted, the center of the cryogenic container can be supported without moving, and it can also be supported against loads.

(e) Since the bearing material is made of a material with a low coefficient of friction, lubricants such as grease and oil are not required.

Therefore, evaporative gas from the lubricant is not generated and the degree of vacuum is not reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing an embodiment of the cryogenic apparatus of the present invention;
2 and 3 are detailed sectional views of the main parts of the support device in FIG. 1. 1...Vacuum insulation tank, 2...Cryogenic container, 3...Superconducting magnet, 4...Liquid helium, 5...Port , 6... Radiation shield, 7 a, 7 b... Support device, 71... Bearing material, 72... Support rod,
73.76...Flange, 74.78...
...Mounting bolt, 77...Gasket.

Claims (1)

[Scope of utility model registration request] In a cryogenic apparatus equipped with a cryogenic container in a vacuum insulation tank, the cryogenic container is supported in surface contact with a bearing material made of a material that exhibits a low coefficient of friction in vacuum against vertical loads, and this bearing The other side of the material is fixed to the vacuum insulation tank via a support rod with low thermal conductivity, while for horizontal loads, the cryogenic container is brought into surface contact with a bearing material made of a material that exhibits a low coefficient of friction in vacuum. A load support device for a cryogenic device, characterized in that the other surface of the bearing material is fixed to the vacuum insulation tank via a support rod having low thermal conductivity and a heat shrinkage absorbing spring.