JPS6231807B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to an inner tank support structure in a liquid helium reservoir of a superconducting magnet used in a superconducting magnetically levitated vehicle or the like.

In a superconducting magnet, in order to maintain a superconducting coil in a superconducting state, it is necessary to cool the superconducting coil to an extremely low temperature by filling a sealed container containing the coil with liquid helium as a coolant. In this case, liquid helium evaporates due to self-heating of the coil and heat intrusion from the outside, so in order to maintain the extremely low temperature state, a liquid helium reservoir must be provided and liquid helium must be replenished into the coil portion as needed. Moreover, since liquid helium is a scarce resource, expensive, and has a small latent heat of vaporization, it is desired to use it effectively by minimizing the amount of heat that enters the liquid helium reservoir.

Therefore, in general, this type of liquid helium reservoir has a double-walled structure in which an inner tank for storing helium is thermally insulated and supported within an outer tank with a vacuum inside, similar to the coil part of a superconducting magnet. Liquid helium is stored in the inner tank.

FIG. 1 shows an example of the above-mentioned superconducting magnet device, in which a superconducting coil 1 is installed in a coil part inner tank 2 which is a sealed container in the shape of a track ring, and the inner tank 2 is a coil part whose inside is evacuated. It is thermally insulated and fixed within the outer tank 3. On the other hand, a liquid helium reservoir 4 is provided above the coil outer tank 3. This liquid helium reservoir 4 includes an outer tank 5 which is a vacuum container that communicates internally with the coil outer tank 3, and an inner tank for storing liquid helium that is mounted and supported within the outer tank 5 via a thermally insulating support 6. 7, and the liquid helium in the inner tank 7 can be replenished into the coil inner tank 2 through the connecting pipe 8. Note that 9 and 10 are ports for inlet and outlet of coolant and the like.

Here, the support structure using the heat insulating support 6 that is interposed between the outer tank 5 and the inner tank 7 of the liquid helium reservoir 4 and supports the inner tank minimizes heat intrusion from the outside. It must not only have good thermal insulation properties, but also have sufficient strength and rigidity to withstand the vibrations and shocks that occur during driving when used in a vehicle. Note that the same applies to the inner tank support of the coil portion of the superconducting magnet, but since it is not related to the gist of the present invention, the explanation will be omitted.

The conventional inner tank support structure of the liquid helium reservoir 4 will be described with reference to FIGS. 2 and 3. FIG. 2 is an enlarged sectional view taken along the line - in FIG. 1, and FIG. In the enlarged cross-sectional view, the thermal insulation support 6 supporting both ends of the inner tank 7 for storing liquid helium is of an arrow spring type, and includes an intermediate support member 11 made of metal such as stainless steel in the shape of a quadrilateral frame; This intermediate support member 1
1, hold the proximal end on each side of
A, 12B, and two inner and outer support plates 14A and 14B, each of which is tightened and fixed with bolts and nuts 13 and protruded radially.The inner and outer support plates 14A and 14B on each side are made of high strength material such as FRP. In addition, it is in the form of a strip made of a material with good thermal insulation properties,
They are arranged in a V-shape at appropriate angles so that the inside and outside are approximately symmetrical, that is, they form a kind of arrow spring. Such arrow spring type heat insulating supports 6 are arranged at both ends of the inner tank 7, and each inner support plate 14A thereof is provided.
The tips of the outer support plates 14B are tightened and fixed to the support seats 15 provided at four locations on the outer peripheral edge of the inner tank 7 using the presser fittings 16A, 16B and the bolts 17, and the tips of the outer support plates 14B are removed. Four support seats 19 of an aluminum support ring 18 fixed to the inner circumference of the tank 5
The inside of the outer tank 5 supports the inner tank 7 by tightening and fixing the retaining metal fittings 20 and bolts 21. That is, since the outer tank 5 and the inner tank 7 are connected by the band-shaped inner and outer support plates 14A and 14B arranged so as to be folded back in a V-shape at the intermediate support member 11, the inner tank 7 This configuration allows for a long distance from the outside to minimize heat intrusion from the outside. In addition, as shown in FIG. 3, the intermediate support member 11 is
As shown by A and 11B, the heat insulation effect can be further enhanced by dividing the inner and outer parts and providing an intermediate heat shielding plate 22 between the inner and outer parts.

By the way, in the inner tank support structure of the liquid helium reservoir 4 described above, there is a support seat, that is, an outer support plate 14B that receives the outer end of the arrow spring type thermal insulation support 6.
Outer tank side support seat 19 that receives and fixes each tip of...
is formed on a support ring 18, and the support ring 18 is welded and fixed to the airtight welded part of the outer tank 5, which is a vacuum container, in order to maintain the airtightness of the outer tank 5 and to reinforce the vacuum resistance. In other words, the outer tank 5 includes a cylindrical body portion 5A, and closing lid portions 5B, 5B (first
(see figure), but first, the body part 5
The support ring 18 is fixed to the open edge of A by continuous airtight welding over the entire circumference, and then the lid body part 5B is similarly airtightly welded continuously over the entire circumference to the support ring 18. and fix the support ring 18.
was fixed and the outer tank 5 was sealed. For this purpose, the support ring 18 made of aluminum is airtightly welded.
When performing B, a large heat contraction occurs, and as a result, the support plate 14B, which has a spring structure, may become loose, and the support plate 14B may be susceptible to high heat.
Since it is made of FRP, etc., there is a problem of strength deterioration due to the heat effect from welding, and it is necessary to devise a cooling method during welding and retightening of the support plate, etc., and to obtain a reliable support structure. The manufacturing and assembly work was extremely difficult.

This invention was made in view of the above circumstances, and its purpose is to prevent the outer tank side support ring and support plate of the arrow spring type thermal insulating support from thermal shrinkage, loosening, or strength deterioration due to airtight welding of the outer tank. The object of the present invention is to provide a high-performance inner tank support structure that is not affected by the heat mentioned above and can be easily manufactured and assembled.

That is, in this invention, a support ring having an outer tank-side support seat for receiving the end of the arrow spring type heat insulating support is attached to the inner periphery of the body of the outer tank from the airtight welding points of the lid body for closing both ends to the body. It is characterized by a support structure in which the parts are fitted and fixed in a spaced-apart manner, and are not affected by heat due to the airtight welding as much as possible.

An embodiment of the present invention will be described below with reference to FIG. Note that this Figure 4 is a cross-sectional view of a portion corresponding to Figure 3 above, and the same parts in the figure that have the same configuration as those in Figure 3 are given the same reference numerals to simplify the explanation. do.

Here, the outer end of the arrow spring type heat insulating support 6, that is, each tip of the outer support plate 14B...
The support ring 18C is integrally formed with the outer tank support seat 19 which is tightened and fixed with the bolts 21.
Unlike the support ring 18 shown in FIG.
The support ring 18C is fitted deeply into the inner periphery of the body 5A at a position far inward from its open end, and is inserted into the inner periphery of the body 5A in the circumferential direction. They are fixed by spot welding at appropriate intervals.
The outer tank 5 is constructed by directly butting the closing lid part 5B against the open end of the body part 5A and performing airtight welding continuously over the entire circumference.

In the above structure, by fitting and fixing the support ring 18C into the inner periphery of the body part 5A of the outer tank 5, the fixing position of the support ring 18C can be adjusted to the airtight welding area between the body part 5A of the outer tank 5 and the lid part 5B. This makes it possible to reduce the thermal influence on the support ring 18C due to the airtight welding of the outer tank, and also to reduce the heat effect on the support ring 18C.
Thermal influence on the support plate 14B can also be eliminated. In addition, since the support ring 18C is fixed to the body portion 5A of the outer tank 5 by spot welding, it is much less affected by heat than continuous airtight welding around the entire circumference, and is less likely to be affected by heat shrinkage. There are almost no inconveniences. Furthermore, since the work of fixing the support ring 18C can be carried out before attaching the support plates 14B..., there is no need to have a thermal effect on the support plates 14B due to welding, and after fixing the support ring 18C, the support plate 14B...
By installing..., there is no need to make adjustments to remove slack, and accurate assembly is possible.

In addition, according to the above structure, the number of airtight welds around the entire circumference of the outer tank 5 can be reduced from 4 to 2, which reduces the number of assembly steps and eliminates the possibility of airtight leakage. This will help reduce the amount of waste.

FIG. 5 shows another embodiment of this invention,
The support ring 18D having a tapered outer circumferential surface is fitted and fixed to the inner circumferential surface of the body portion 5A of the outer tank 5 via a wedge 23, which eliminates the need for spot welding and improves the structure of the above embodiment. This can further improve the effect. In addition, the above wedge 23
Since this embodiment is the same as the embodiment shown in FIG. 4 except that , the same reference numerals are given to the same parts in the drawings and the explanation thereof will be omitted.

Since this invention is made as detailed above, the outer tank side support ring and support plate of the arrow spring type heat insulating support for supporting the inner tank of the liquid helium reservoir can be prevented from shrinking or loosening due to airtight welding of the outer tank. It is not subject to heat effects such as strength deterioration, and can be easily manufactured and assembled, resulting in a high-performance support structure.

[Brief explanation of the drawing]

Figure 1 is a schematic diagram of a superconducting magnet equipped with a conventional liquid helium reservoir, Figure 2 is an enlarged sectional view of the liquid helium reservoir taken along the line - in Figure 1, and Figure 3 is the line - in Figure 2. FIG. 4 is a sectional view of a portion corresponding to FIG. 3 showing one embodiment of the present invention, and FIG. 5 is a sectional view of the same portion showing another embodiment of the present invention. 4...Liquid helium reservoir, 5...Outer tank, 5A...Outer tank body, 5B...Outer tank closing lid part, 6...Arrow spring type thermal insulation support, 7...Inner tank, 11...Intermediate support member, 1
4A, 14B...Support plate, 15...Inner tank side support seat, 1
8, 18C, 18D...Support ring, 19...Outer tank side support seat, A, B, C...Airtight welding location.

Claims (1)

[Claims] 1 The liquid helium tank in the superconducting magnet is
In a support structure that is supported in an outer tank, which is a vacuum container, by spring-type heat insulating supports attached to both ends, the support ring has an outer tank-side support seat that receives the outer end of the above-mentioned spring-type insulating supports. A liquid helium reservoir inner tank support structure in a superconducting magnet, characterized in that the liquid helium reservoir inner tank support structure in a superconducting magnet is constructed by being fitted and fixed to the inner periphery of the body part of the outer tank at a distance from the airtight welded parts of the lid parts for closing both ends to the body part.