JP2000091116A - Superconducting cryogenic equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve cooling performance of a heat shielding plate by eliminating residual water content in piping, and cope with dimensional restriction of piping constitution. SOLUTION: This superconducting cryogenic equipment is provided with a superconducting coil 1, a liquid helium vessel 2, a heat shielding plate 2 and an outer tank 7, and has a heat shielding plate cooling structure of a gravity- drop circulating system using liquid nitrogen. In this case, a drain pipe 9 which is interconnected with the outside of the outer tank 7 and drains residual water content in a cooling piping 4 to the outside is connected with a lower nitrogen pool 6 of the cooling piping 4.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superconducting cryogenic device such as a superconducting magnet having a cooling structure of a natural falling circulation system using liquid nitrogen, such as a superconducting magnet. The present invention relates to a superconducting cryogenic device that can improve the cooling performance of a superconducting cryogenic device and can cope with dimensional restrictions on the piping configuration.

[0002]

2. Description of the Related Art Recently, as one of superconducting cryogenic devices such as superconducting magnets, a superconducting cryogenic device having a heat shield plate cooling structure of a natural fall circulation type using liquid nitrogen has been widely used.

FIG. 7 is a perspective view showing a configuration example of a conventional superconducting cryogenic device of this type, and FIG. 8 is a sectional view showing a configuration example of the same superconducting cryogenic device. 7 and 8, a superconducting cryogenic device includes a superconducting coil 1, a helium container 2 for housing the superconducting coil 1, and a heat shield for reducing heat intrusion into the helium container 2 from outside. The helium container 2 and the heat shield plate 3 are housed therein.

On the other hand, a nitrogen tank 10 containing liquid nitrogen therein is installed above the outer tank 7, and liquid nitrogen supplied from the nitrogen tank 10 via a connection pipe 8 is supplied to the heat shield plate 3. To the upper nitrogen reservoir 5 installed above the
Liquid nitrogen is supplied from the upper nitrogen reservoir 5 using gravity as a driving force.
It is branched into a cooling pipe 4 thermally connected to the heat shield plate 3, and is collected in the lower nitrogen reservoir 6 while cooling the heat shield plate 3 in the flowing process. Further, the heat shield plate 3 is cooled in the flow process. The vaporized nitrogen is raised in the cooling pipe 4 in a direction opposite to the flow direction of the liquid nitrogen, collected in the upper nitrogen reservoir 5, and naturally dropped by the liquid nitrogen so as to be collected in the nitrogen tank 10 through the connection pipe 8. It has a cooling configuration for the circulation type heat shield plate 3.

[0005]

However, the superconducting cryogenic device having the cooling structure of the heat shield plate of the natural fall circulation type using liquid nitrogen driven by gravity has the following problems. .

That is, the water remaining in the cooling pipe 4 is condensed and adheres to the inside of the cooling pipe 4, and as a result, the cross-sectional area of the nitrogen circulation passage is reduced, and the cooling performance of the heat shield plate 3 is reduced. It is feared that it will decrease.

In addition, since the system is a natural fall circulation system using liquid nitrogen driven by gravity, natural exchange and recovery of liquid nitrogen and vaporized nitrogen in the piping are required, and the surface tension between the vaporized nitrogen and the piping is reduced. Due to the restriction on the inner diameter of the pipe due to the above-mentioned relationship, the pipe configuration is restricted in terms of dimensions, and must be difficult.

SUMMARY OF THE INVENTION It is an object of the present invention to improve the cooling performance of a heat shield plate by removing residual moisture in a pipe in a cryogenic device such as a superconducting magnet having a heat shield plate cooling structure of a natural fall circulation type using liquid nitrogen. It is another object of the present invention to provide a superconducting cryogenic device capable of coping with dimensional restrictions of a piping configuration.

[0009]

In order to achieve the above object, according to the first aspect of the present invention, a superconducting coil, a helium container accommodating the superconducting coil therein, and heat from the outside to the helium container are provided. Liquid that is provided through a connection pipe from a nitrogen tank installed on the upper part of the outer tank, comprising a heat shield plate for reducing intrusion, and an outer tank for housing the helium container and the heat shield plate inside. Nitrogen is guided to the upper nitrogen reservoir installed above the heat shield plate, and from this upper nitrogen reservoir, liquid nitrogen is branched and flows into the cooling pipe thermally connected to the heat shield plate using gravity as a driving force. While cooling the heat shield plate in the lower nitrogen reservoir, the heat shield plate is further cooled in the flowing process, and the vaporized nitrogen is raised in the cooling pipe in the direction opposite to the liquid nitrogen flow direction and the upper nitrogen In a superconducting cryogenic device having a heat shield plate cooling configuration of a natural fall circulation type with liquid nitrogen that is collected in a nitrogen tank via a connection pipe, the lower nitrogen pool of the cooling pipe and the outside of the outer tank A drain pipe is installed to communicate the residual moisture in the cooling pipe to the outside.

Therefore, in the superconducting cryogenic apparatus according to the first aspect of the present invention, a drain pipe is provided in the lower nitrogen reservoir of the cooling pipe to communicate with the outside of the outer tank and discharge the residual moisture in the cooling pipe to the outside. Therefore, for example, when the temperature rises during periodic inspection,
Dry gas or the like is pumped into the drainage pipe, and water remaining in the cooling pipe and accumulated in the lower nitrogen reservoir can be easily discharged to the outside through the drainage pipe. Accordingly, it is possible to prevent the cooling pipe from being clogged due to freezing of residual moisture in the cooling pipe or the like, and the cooling performance of the heat shield plate accompanying the blocking is reduced.

According to the second aspect of the present invention, in the first aspect,
In the superconducting cryogenic device according to the invention, the connection pipe is composed of two vertically independent pipes so as to promote the supply of liquid nitrogen and the recovery of vaporized nitrogen.

Therefore, in the superconducting cryogenic apparatus according to the second aspect of the present invention, the connecting pipe for connecting the nitrogen tank and the upper nitrogen reservoir is composed of two vertically independent pipes, so that the liquid nitrogen is vaporized. By separating and collecting and circulating the nitrogen, the circulation of the nitrogen is promoted, the supply of the nitrogen to the cooling pipe is secured, and the cooling performance of the heat shield plate can be further improved.

Further, according to a third aspect of the present invention, in the superconducting cryogenic device according to the first or second aspect,
The connection pipe is arranged so that the cross-sectional shape is elliptical and flat in the left-right direction.

Therefore, in the superconducting cryogenic apparatus according to the third aspect of the present invention, the cross-sectional shape of the connection pipe that connects the nitrogen tank and the upper nitrogen reservoir is made elliptical to secure the cross-sectional area of the pipe and to reduce the flatness in the left-right direction. By separating the heat shield plate from the heat shield plate, it is possible to separate the liquid and vaporized nitrogen in the connection pipe by separating them into the upper vaporized nitrogen area and the lower liquid nitrogen area inside the connection pipe. Cooling performance can be ensured. In addition, by making the cross-sectional shape of the connection pipe elliptical, the dimension in the width direction is shortened. Therefore, the size of the connection pipe can be reduced, and the dimensional restriction of the pipe configuration can be handled. .

[0015] On the other hand, in the invention of claim 4, the above-mentioned claim 1 is provided.
In the superconducting cryogenic apparatus according to any one of claims 3 to 3, two bellows are vertically arranged in parallel in the connection pipe so as to promote the supply of liquid nitrogen and the recovery of vaporized nitrogen. are doing.

Therefore, in the superconducting cryogenic apparatus according to the fourth aspect of the present invention, the exchange and circulation of liquid nitrogen and vaporized nitrogen are promoted by installing two bellows vertically in the middle of the connection pipe. Thus, the cooling performance of the heat shield plate can be secured.

According to the fifth aspect of the present invention, in the fourth aspect,
In the superconducting cryogenic device according to the invention, a guide pipe for guiding only axial expansion and contraction is provided inside the bellows in only one of the two bellows installed in parallel.

Therefore, in the superconducting cryogenic apparatus according to the fifth aspect of the present invention, only one of the two bellows installed in parallel is provided with a guide pipe for guiding that allows only expansion and contraction in the axial direction. Since the expansion and contraction of the two bellows are performed without hindrance, the circulation and exchange of liquid nitrogen and vaporized nitrogen are promoted, and the cooling performance of the heat shield plate can be more effectively secured.

Further, according to a sixth aspect of the present invention, in the superconducting cryogenic apparatus according to any one of the first to fifth aspects of the present invention, another superconducting cryogenic device is provided in the middle of a drainage pipe communicating with the outside of the outer tank. A relay reservoir connected to the cooling pipe of the heat shield plate is installed.

Therefore, in the superconducting cryogenic device according to the invention of claim 6, during the drainage pipe communicating with the outside of the outer tank,
By installing a relay reservoir connected to the cooling pipe of the other heat shield plate, the residual moisture in the piping is prevented from entering the cooling piping of the other heat shield plate via the relay reservoir,
In addition, the moisture can be easily discharged to the outside by the pressure of the drying gas or the like from the outside, and the cooling performance of the heat shield plate can be secured.

[0021]

Embodiments of the present invention will be described below in detail with reference to the drawings. (First Embodiment) FIG. 1 is a schematic diagram showing a configuration example of a superconducting cryogenic device according to the present embodiment, and the same elements as those in FIGS. 7 and 8 are denoted by the same reference numerals. .

Referring to FIG. 1, a superconducting cryogenic apparatus comprises a superconducting coil 1, a helium container 2 for accommodating the superconducting coil 1, and a heat shield for reducing external heat intrusion into the helium container 2. Plate 3 and an outer tank 7 for housing the helium container 2 and the heat shield plate 3 therein.
It is composed of

On the other hand, a nitrogen tank 10 containing liquid nitrogen therein is installed above the outer tank 7, and liquid nitrogen supplied from the nitrogen tank 10 via the connection pipe 8 is supplied to the heat shield plate 3. To the upper nitrogen reservoir 5 installed above the
Liquid nitrogen is supplied from the upper nitrogen reservoir 5 using gravity as a driving force.
The branch flows into a cooling pipe 4 thermally connected to the heat shield plate 3 and is collected in the lower nitrogen reservoir 6 while cooling the heat shield plate 3 in the flowing process. The heat shield plate 3 is further cooled in the flow process. The vaporized nitrogen is raised in the cooling pipe 4 in the direction opposite to the flowing direction of the liquid nitrogen, collected in the upper nitrogen reservoir 5, and naturally dropped by the liquid nitrogen so as to be collected in the nitrogen tank 10 through the connection pipe 8. It has a cooling configuration for the circulation type heat shield plate 3.

Further, in the lower nitrogen reservoir 6 of the cooling pipe 4, a drain pipe 9 communicating with the outside of the outer tank 7 and discharging the residual moisture in the cooling pipe 4 to the outside is provided. Next, in the superconducting cryogenic device of the present embodiment configured as described above,
The liquid nitrogen in the upper nitrogen reservoir 5 is distributed to the cooling pipe 4 having a certain angle or more with respect to the horizontal and flows down.
By cooling the heat shield plate 3 which is thermally connected to the helium container 2, heat intrusion from the outside into the helium container 2 can be reduced.

The liquid nitrogen in the cooling pipe 4 is supplied to the lower nitrogen reservoir 6
And gradually evaporates in the middle of the flow, and at the same time, overcomes the gravity difference between the liquid and the vaporized nitrogen, and the surface tension and adhesive force of the vaporized nitrogen and the piping, and rises in the cooling piping 4 to exchange with the liquid portion. And is accumulated on the upper part of the upper nitrogen reservoir 5.

As described above, during the process in which the vaporized nitrogen cools the heat shield plate 3 in the cooling pipe 4 and is recovered in the upper nitrogen reservoir 5, when the residual moisture in the cooling pipe 4 is present, it freezes. By adhering to the inside of the pipe, the actual cross-sectional area of the pipe is reduced, which hinders the circulation and exchange of liquid nitrogen and vaporized nitrogen, and leads to a reduction in the cooling performance of the heat shield plate 3.

In this respect, in the present embodiment, the drainage pipe 9 communicating with the outside of the outer tub 7 is provided in the lower nitrogen reservoir 6 of the cooling pipe 4 so that, for example, when the temperature is raised at the time of periodic inspection, the water is drained. Dry gas or the like is pumped into the drain pipe 9, and water remaining in the cooling pipe 4 and stored in the lower nitrogen reservoir 6 can be easily discharged to the outside through the drain pipe 9.

This makes it possible to easily discharge the residual moisture in the cooling pipe 4 to the outside, to block the cooling pipe 4 due to freezing of the residual moisture in the cooling pipe 4 and to cause the heat shield plate 3 Since the cooling performance of the helium container 2 can be prevented from lowering, heat intrusion into the helium container 2 from the outside can be suppressed.

As described above, in the superconducting cryogenic apparatus according to the present embodiment, the water remaining in the cooling pipe 4 can be easily removed by exhausting dry gas or the like from the outside. It is possible to prevent the cooling performance of the heat shield plate 3 from lowering.

(Second Embodiment) FIG. 2 is a partial schematic diagram showing a configuration example of a superconducting cryogenic device according to the present embodiment. The same parts as those in FIG. Are omitted, and only different portions will be described here.

That is, as shown in FIG. 2, the superconducting cryogenic device according to the present embodiment has a nitrogen tank 10 shown in FIG.
The connection pipe 8 for communicating the gas and the upper nitrogen reservoir 5 is composed of two vertically independent pipes 8a and 8b so as to promote the supply of liquid nitrogen and the recovery of vaporized nitrogen.

Next, in the superconducting cryogenic apparatus of the present embodiment configured as described above, the connection pipe 8 communicating the nitrogen tank 10 and the upper nitrogen reservoir 5 is connected to the supply of liquid nitrogen and the recovery of vaporized nitrogen. Is constituted by two vertically independent pipes 8a and 8b so that liquid nitrogen and vaporized nitrogen are separated and collected and circulated, thereby promoting the circulation of nitrogen and cooling pipe 4 Nitrogen supply to the heat shield plate 3 and the cooling performance of the heat shield plate 3 can be improved.

As described above, in the superconducting cryogenic device of the present embodiment, the cooling performance of the heat shield plate 3 by the cooling pipe 4 can be further improved. (Third Embodiment) FIG. 3 is a partial schematic diagram showing a configuration example of a superconducting cryogenic device according to the present embodiment. The same parts as those in FIG. Here, only the different parts will be described.

That is, as shown in FIG. 3, the superconducting cryogenic device according to the present embodiment has the nitrogen tank 10 shown in FIG.
The connection pipe 8 that communicates with the upper nitrogen reservoir 5 is configured to be an elliptical pipe 8c having an elliptical cross section and to be flattened in the left-right direction.

Next, in the superconducting cryogenic apparatus of the present embodiment configured as described above, the connection pipe connecting the nitrogen tank 10 and the upper nitrogen reservoir 5 is made elliptical pipe 8c to secure a pipe cross-sectional area. In addition, by being disposed so as to be flat in the left-right direction, the gas is separated into an upper vaporized nitrogen region and a lower liquid nitrogen region inside the elliptical pipe 8c, and the liquid and the vaporized nitrogen in the elliptical pipe 8c are separated. Separation and replacement can be facilitated, and the cooling performance of the heat shield plate 3 can be ensured.

Further, since the connecting pipe is formed as the elliptical pipe 8c, the dimension in the width direction is shortened. Therefore, the size of the elliptical pipe 8c is reduced to meet the dimensional restrictions of the pipe configuration. Can be.

As described above, in the superconducting cryogenic device of the present embodiment, it is possible to ensure the cooling performance of the heat shield plate 3 and to cope with the dimensional restrictions of the piping configuration.

(Fourth Embodiment) FIG. 4 is a partial schematic view showing a configuration example of a superconducting cryogenic device according to the present embodiment. The same parts as those in FIG. Are omitted, and only different portions will be described here.

That is, as shown in FIG. 4, the superconducting cryogenic device of the present embodiment has a nitrogen tank 10 shown in FIG.
Two bellows joints 11a and 11b are vertically arranged in parallel in the middle of a connection pipe 8 that communicates with the upper nitrogen reservoir 5 so as to promote the supply of liquid nitrogen and the recovery of vaporized nitrogen.

Next, in the superconducting cryogenic apparatus according to the present embodiment configured as described above, two bellows joints 11a are provided in the middle of the connection pipe 8 that connects the nitrogen tank 10 and the upper nitrogen reservoir 5. , 11b, the upper bellows joint 11b mainly circulates vaporized nitrogen, and the lower bellows joint 11a circulates liquid nitrogen, thereby increasing the diameter of the bellows joints 11a, 11b. Without exchanging and circulating liquid nitrogen and vaporized nitrogen, the cooling performance of the heat shield plate 3 can be ensured.

As described above, in the superconducting cryogenic device of the present embodiment, the cooling performance of the heat shield plate 3 can be ensured. (Fifth Embodiment) FIG. 5 is a partial schematic diagram showing a configuration example of a superconducting cryogenic device according to the present embodiment, and the same parts as those in FIG. Here, only the different parts will be described.

That is, as shown in FIG. 5, the superconducting cryogenic device according to the present embodiment has only one of the two bellows joints 11a and 11b installed in parallel in FIG. The bellows joint 11a) is provided with a guide pipe 12 for guiding that allows only expansion and contraction in the axial direction.
a, a bellows joint 11c with a guide tube is provided.

Next, in the superconducting cryogenic device according to the present embodiment configured as described above, only one of the two bellows joints 11a and 11b installed in parallel has only the axial expansion and contraction. The two guide bellows joints 11b, 11c
Since the expansion and contraction of the heat shield plate 3 are performed without any trouble, the circulation and exchange of the liquid nitrogen and the vaporized nitrogen are promoted, and the cooling performance of the heat shield plate 3 can be more effectively secured.

As described above, in the superconducting cryogenic device of the present embodiment, the cooling performance of the heat shield plate 3 can be more effectively secured. (Sixth Embodiment) FIG. 6 is a schematic diagram showing a configuration example of a superconducting cryogenic device according to the present embodiment. The same parts as those in FIG. Here, only different parts will be described.

That is, as shown in FIG. 6, the superconducting cryogenic apparatus according to the present embodiment has a cooling pipe for the other heat shield plate 3 in the middle of a drain pipe 9 communicating with the outside of the outer tank 7 in FIG. The relay reservoir 13 connected to the relay 4 is installed.

Next, in the superconducting cryogenic apparatus of the present embodiment configured as described above, the cooling pipe 4 of the other heat shield plate 3 is provided in the middle of the drain pipe 9 communicating with the outside of the outer tank 7.
Is installed to prevent the residual moisture in the pipe from entering the cooling pipe 4 of the other heat shield plate 3 through the relay tank 13 and to provide the dry gas from the outside. The water can be easily discharged to the outside by such pressure feeding, and the cooling performance of the heat shield plate 3 can be secured.

As described above, in the superconducting cryogenic device according to the present embodiment, the residual moisture in the piping is
The cooling performance of the heat shield plate 3 can be ensured while preventing the heat shield plate 3 from entering the cooling pipe 4.

[0048]

As described above, according to the superconducting cryogenic apparatus of the present invention, the cooling performance of the heat shield plate is improved by removing the residual moisture inside the pipe, and the dimensional restriction of the pipe structure is eliminated. It is possible to respond.

[Brief description of the drawings]

FIG. 1 is a schematic diagram showing a first embodiment of a superconducting cryogenic device according to the present invention.

FIG. 2 is a partial schematic diagram showing a second embodiment of the superconducting cryogenic device according to the present invention.

FIG. 3 is a partial schematic view showing a third embodiment of a superconducting cryogenic device according to the present invention.

FIG. 4 is a partial schematic diagram showing a fourth embodiment of the superconducting cryogenic device according to the present invention.

FIG. 5 is a partial schematic diagram showing a fifth embodiment of the superconducting cryogenic device according to the present invention.

FIG. 6 is a schematic diagram showing a sixth embodiment of the superconducting cryogenic device according to the present invention.

FIG. 7 is a perspective view showing a configuration example of a conventional superconducting cryogenic device.

FIG. 8 is a sectional view showing a configuration example of a conventional superconducting cryogenic device.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 ... Superconducting coil, 2 ... Helium container, 3 ... Heat shield plate, 4 ... Cooling piping, 5 ... Upper nitrogen reservoir, 6 ... Lower nitrogen reservoir, 7 ... Outer tank, 8a, 8b ... Connection piping, 8c ... Elliptical piping, 9: drainage pipe, 10: nitrogen tank, 11a, 11b: bellows joint, 11c: bellows joint with guide pipe, 12: guide pipe.

Claims (6)

[Claims] 1. A superconducting coil, a helium container accommodating the superconducting coil therein, a heat shield plate for reducing heat intrusion from the outside into the helium container, and the helium container and the heat shield plate inside the helium container. An outer tank that is stored in the outer tank, and guides liquid nitrogen supplied via a connection pipe from a nitrogen tank installed at an upper part of the outer tank to an upper nitrogen reservoir installed at an upper part of the heat shield plate, From the upper nitrogen reservoir, liquid nitrogen is branched into a cooling pipe thermally connected to the heat shield plate using gravity as a driving force, and is collected in the lower nitrogen reservoir while cooling the heat shield plate in the process of flowing down. Nitrogen vaporized by cooling the heat shield plate in the flow-down process is raised in the cooling pipe in a direction opposite to the flow-down direction of liquid nitrogen and collected in the upper nitrogen reservoir, via the connection pipe. In a superconducting cryogenic device having a heat-shield plate cooling structure of a natural fall circulation type using liquid nitrogen to be collected in a nitrogen tank, the cooling is performed by communicating with a lower nitrogen reservoir of the cooling pipe to the outside of the outer tank. A superconducting cryogenic device comprising a drain tube for discharging residual moisture in a pipe to the outside. 2. The superconducting cryogenic apparatus according to claim 1, wherein the connection pipe is composed of two vertically independent pipes so as to promote supply of liquid nitrogen and recovery of vaporized nitrogen. A superconducting cryogenic device characterized by the following. 3. The superconducting cryogenic device according to claim 1, wherein the connection pipe is arranged so as to have an elliptical cross-sectional shape and to be flat in the left-right direction. Superconducting cryogenic device. 4. The method according to claim 1, wherein
In the superconducting cryogenic device according to the above paragraph, two bellows are vertically arranged in parallel in the middle of the connection pipe so as to promote supply of liquid nitrogen and recovery of vaporized nitrogen. Cryogenic equipment. 5. The superconducting cryogenic device according to claim 4, wherein only one of the two bellows installed in parallel is provided with a guide pipe for guiding allowing only expansion and contraction in the axial direction. A superconducting cryogenic device provided inside a bellows. 6. The method according to claim 1, wherein
The superconducting cryogenic device according to claim 1, wherein a relay reservoir connected to a cooling pipe of another heat shield plate is provided in the middle of a drainage pipe communicating with the outside of the outer tank. .