JPH11340028A - Super-conducting coil device and method for adjusting its temperature - Google Patents

Abstract

PROBLEM TO BE SOLVED: To efficiently cool from room temperature to a specified temperature in a short time, by allowing a cooling piping to comprise a first shield through part penetrating a radiation shield in thermally non-contact state, and a second shield through part penetrating the radiation shield in thermally contacted state. SOLUTION: A cooling piping 11 wherein, with both end parts drawn out of a vacuum vessel 1, an intermediate part thermally contacts to a super- conducting coil comprises a first shield through part 11a penetrating a radiation shield 3 in thermally non-contact state and a second shield through part 11b penetrating the radiation shield 3 while thermally contacted through a conduction member 12 of good heat-conduction material. A heat-exchanger is provided in the second shield through part 11b of the cooling piping 11. The heat- exchanger comprises a good heat-conduction material such as copper and porous structure for raised heat-exchange efficiency with a larger contact area to a coolant flowing in the cooling pipe 11 and a fluid for raising heat.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a superconducting coil device provided with a refrigerator for cooling a superconducting coil and a radiation shield by conduction, and a method for adjusting the temperature thereof.

[0002]

2. Description of the Related Art FIG. 6 is a block diagram showing a conventional superconducting coil device disclosed in, for example, Japanese Patent Application Laid-Open No. 8-69911. In the figure, 1 is a vacuum vessel, 2 is a superconducting coil housed in the vacuum vessel 1, 3 is a radiation shield provided around the superconducting coil 2 in the vacuum vessel 1, 4 is a superconducting coil 2 and a radiation shield. A refrigerator that cools 3 by conduction, 5 is a compressor connected to the refrigerator 4, 6 has both ends drawn out of the vacuum vessel 1, and an intermediate portion is in thermal contact with the superconducting coil 2. The cooling pipe 7 is a helium gas container connected to one end of the cooling pipe 6 via a pressure flow controller 8.

In the above-described superconducting coil device (superconducting magnet), the superconducting coil 2 and the refrigerator 4 are in thermal contact, and the superconducting coil 2 is cooled by operating the refrigerator 4. Further, a radiation shield 3 is arranged between the vacuum container 1 at room temperature and the superconducting coil 2 at extremely low temperature in order to reduce radiant heat applied to the superconducting coil 2.
Further, the radiation shield 3 is connected to the superconducting coil 2 of the refrigerator 4.
It is cooled by a cooling end that is hotter than the cooling end for use.

On the other hand, liquid helium is always stored in cooling pipe 6 which is in thermal contact with superconducting coil 2.
This liquid helium is cooled by the refrigerator 4 to prevent the temperature of the superconducting coil 2 from rising. Further, at the time of the power failure of the refrigerator 4, the quench of the superconducting coil 2 is prevented by the liquid helium in the cooling pipe 6.

[0005]

In the conventional superconducting coil device configured as described above, since the superconducting coil 2 is cooled only by the refrigerator 4, the superconducting coil 2 is particularly large when the superconducting coil 2 is large. There is a problem that it takes a considerably long time to cool the coil 2 from room temperature to a predetermined temperature.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and a superconducting coil device and a superconducting coil device capable of efficiently cooling a superconducting coil from room temperature to a predetermined temperature in a short time. The purpose is to obtain a temperature control method.

[0007]

According to a first aspect of the present invention, a superconducting coil device is provided around a vacuum container, a superconducting coil housed in the vacuum container, and a superconducting coil in the vacuum container. A cooling device that cools the superconducting coil and the radiation shield by conduction, and a cooling pipe whose both ends are drawn out of the vacuum vessel and whose middle part is in thermal contact with the superconducting coil. The pipe is the first that penetrates the radiation shield in a thermally non-contact state.
And a second shield penetration portion that penetrates the radiation shield in a state of thermal contact.

[0008] A superconducting coil device according to a second aspect of the present invention is one in which a heat exchanger is provided in the cooling pipe in the second penetrating portion.

According to a third aspect of the present invention, there is provided a superconducting coil device comprising: a vacuum container; a superconducting coil housed in the vacuum container; a radiation shield provided around the superconducting coil in the vacuum container; The refrigerator includes a refrigerator that cools the coil and the radiation shield by conduction, and a cold storage member that is in thermal contact with the radiation shield.

According to a fourth aspect of the present invention, there is provided a method for adjusting a temperature of a superconducting coil device, comprising: a vacuum vessel, a superconducting coil housed in the vacuum vessel, and radiation provided around the superconducting coil in the vacuum vessel. A shield, a refrigerator that cools the superconducting coil and the radiation shield by conduction, and a cooling pipe that has both ends drawn out of the vacuum vessel and an intermediate part in thermal contact with the superconducting coil. First through the radiation shield in a thermally non-contact state
For a superconducting coil device having a shield penetration portion and a second shield penetration portion that penetrates the radiation shield in a state of thermal contact, by flowing a refrigerant from the first shield penetration portion side to the cooling pipe, The superconducting coil is cooled from around room temperature.

According to a fifth aspect of the present invention, there is provided a method for adjusting a temperature of a superconducting coil device, comprising: a vacuum vessel, a superconducting coil housed in the vacuum vessel, and radiation provided around the superconducting coil in the vacuum vessel. A shield, a refrigerator that cools the superconducting coil and the radiation shield by conduction, and a cooling pipe that has both ends drawn out of the vacuum vessel and an intermediate part in thermal contact with the superconducting coil. First through the radiation shield in a thermally non-contact state
Flow of a high-temperature fluid from the side of the second shield penetration portion to the cooling pipe in a superconducting coil device having a shield penetration portion and a second shield penetration portion penetrating the radiation shield in a state of thermal contact Thus, the temperature of the superconducting coil is raised.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiments of the present invention will be described below with reference to the drawings. Embodiment 1 FIG. FIG. 1 is a configuration diagram showing a superconducting coil device according to Embodiment 1 of the present invention, and FIG. 2 is a cross-sectional view of a main part of FIG.

In the figure, 1 is a vacuum vessel, 2 is a superconducting coil housed in the vacuum vessel 1, 3 is a radiation shield provided around the superconducting coil 2 in the vacuum vessel 1, 4 is a superconducting coil 2 A refrigerator 10 for cooling the radiation shield 3 by conduction is a load supporting member for supporting the superconducting coil 2 and the radiation shield 3 from the vacuum vessel 1.

Numeral 11 denotes a cooling pipe whose both ends are drawn out of the vacuum vessel 1 and whose intermediate part is in thermal contact with the superconducting coil 2. As shown in FIG. A first shield penetration portion 11a penetrating the radiation shield 3 in a non-contact state, and a second shield penetration penetrating the radiation shield 3 in a thermal contact state via a conductive member 12 made of a good heat conductive material. Part 11b.

Next, the operation will be described. When performing initial cooling for cooling the superconducting coil 2 from room temperature to a predetermined temperature, the refrigerator 4 is operated and a refrigerant such as liquid nitrogen or liquid helium is injected into the cooling pipe 11. At this time, as shown in FIG. 2, a container containing a refrigerant is connected to a port on the side of the first shield penetrating portion 11a which is not in thermal contact with the radiation shield 3, and the refrigerant is injected into the cooling pipe 11. I do. The injected refrigerant is discharged out of the vacuum vessel 1 from the port on the second shield penetration portion 11b side.

Here, as the refrigerator 4, for example, a Gifford McMahon type (GM) refrigerator is used, and its refrigerating capacity is about 30W up to 50K and 0.5W at 4K. Further, assuming that the weight of the superconducting coil 2 is 100 kg, the time required to cool the superconducting coil 2 from room temperature to 5 K, which can be operated by only this GM refrigerator, is about 100 hours. That is, the refrigerator 4 can maintain the temperature of the superconducting coil 2 with low power consumption during the normal operation, but the initial cooling requires a long time.

On the other hand, the first shield penetration portion 11a
When the refrigerant is injected into the cooling pipe 11 from the side, even if the temperature of the radiation shield 3 is higher than the temperature of the refrigerant, the radiation shield 3
The superconducting coil 2 is directly cooled by the refrigerant because the refrigerant is not affected by the temperature of the superconducting coil. Therefore, the time required for the initial cooling of the superconducting coil 2 can be reduced to about 10 hours.

As described above, after the initial cooling of the superconducting coil 2 is completed, it is not necessary to inject the refrigerant into the cooling pipe 11, and the cooling pipe 11 is closed while being evacuated during normal operation. The temperature of superconducting coil 2 during normal operation is maintained by refrigerator 4.

According to the initial cooling method as described above, since the superconducting coil 2 is cooled by the refrigerant in the cooling pipe 11, the superconducting coil 2 can be efficiently cooled in a short time.

As the refrigerant to be injected into the cooling pipe 11, liquid nitrogen, liquid helium, or the like can be used. For example, after cooling to 100K with liquid nitrogen, the inside of the cooling pipe 11 is replaced with helium gas. Thereafter, it can be cooled to 10K or less with liquid helium.

Next, a method of raising the temperature of the superconducting coil 2 shown in FIG. 1 from the operating temperature to room temperature, for example, for a long-term shutdown or maintenance will be described. When the temperature of the superconducting coil 2 is increased, contrary to the initial cooling, a high-temperature fluid, for example, helium gas at room temperature is supplied from a port on the side of the second shield penetration portion 11b in thermal contact with the radiation shield 3 to the cooling pipe 11. Pour in The helium gas is cooled by the radiation shield 3, raises the temperature of the superconducting coil 2, and is discharged out of the vacuum vessel 1 through a port on the first shield penetration portion 11 b side.

As described above, the fluid at room temperature is applied to the radiation shield 3.
As a result, the temperature of the superconducting coil 2 does not rise rapidly, and no sharp temperature gradient occurs in the superconducting coil 2. Therefore, thermal distortion is prevented from remaining in the superconducting coil 2, and quenching during recooling is prevented. Further, since the temperature of the radiation shield 3 is raised first, the radiation heat enters the superconducting coil 2 almost uniformly, the temperature of the superconducting coil 2 is evenly increased, and the occurrence of thermal distortion is prevented.

Embodiment 2 FIG. Next, FIG. 3 is a sectional view of a main part of a superconducting coil device according to a second embodiment of the present invention. In this example, the heat exchanger 13 is provided in the second shield penetration portion 11b of the cooling pipe 11. The heat exchanger 13 is made of a good heat conductive material such as copper, for example, and has a porous structure in order to increase the contact area with the refrigerant flowing through the cooling pipe 11 and the fluid for raising the temperature to increase the heat exchange efficiency. have. Thus, by providing the heat exchanger 13 in the second shield penetration portion 11b, heat can be efficiently transferred between the radiation shield 3 and the refrigerant or the fluid for raising the temperature.

In the second embodiment, the heat exchanger 13 is provided in the second shield penetration portion 11b.
A similar heat exchanger may be provided inside the thermal contact portion with the superconducting coil 2 to shorten the initial cooling time and the heating time, and reduce the amount of the refrigerant and the fluid used for heating. Can be reduced.

Embodiment 3 Next, FIG. 4 is a configuration diagram showing a superconducting coil device according to Embodiment 3 of the present invention. In the figure, reference numeral 21 denotes a cold storage member provided in the radiation shield 21 and in thermal contact with the radiation shield 21. The cold storage member 21 is made of a material having a large specific heat, such as lead. Other configurations are the same as those of the first embodiment.

FIG. 5 is a relationship diagram showing a calculation example of the temperature rise of the superconducting coil 2 and the radiation shield 3 when the refrigerator 4 of FIG. 4 is stopped. As shown by the solid line in FIG. 5, when the cool storage member 21 is provided, the temperature rise is gradual even when the refrigerator 4 is stopped, so that the amount of heat entering the superconducting coil 2 may also increase rapidly. Instead, the time until the superconducting coil 2 reaches the critical temperature can be greatly increased.

Therefore, when the refrigerator 4 is stopped due to a power failure or the like, the current of the superconducting coil 2 is reduced by an external power supply until the superconducting coil 2 reaches the critical temperature, and the magnetic field energy of the superconducting coil 2 is extracted. Can be. That is, demagnetization can be performed safely without quenching the superconducting coil 2. Further, in the conventional apparatus shown in FIG. 6, the liquid helium in the cooling pipe 6 must be maintained in a liquid state, and a complicated pressure flow rate adjusting device 8 is required. The time required to reach the critical temperature when the refrigerator 4 is stopped can be increased without using a complicated control unit.

[0028]

As described above, in the superconducting coil device according to the first aspect of the present invention, of the first and second shield penetration portions of the cooling pipe, the first shield penetration portion has heat with respect to the radiation shield. Since the second shield penetration part is in thermal contact with the radiation shield, the refrigerant is injected from the first shield penetration part side, so that the initial cooling of the superconducting coil can be efficiently performed in a short time. Can be. Also, the second
By flowing a high-temperature fluid from the shield penetration side of
The temperature of the superconducting coil can be evenly increased while preventing thermal distortion from remaining in the superconducting coil.

In the superconducting coil device according to the second aspect of the present invention, since the heat exchanger is provided in the cooling pipe in the second penetrating portion, heat is efficiently transferred between the refrigerant or the fluid for raising the temperature and the radiation shield. Can give and receive.

Since the superconducting coil device according to the third aspect of the present invention includes the cold storage member that is in thermal contact with the radiation shield, the superconducting coil is not quenched when the refrigerator is stopped without providing a complicated control unit. , Can be safely degaussed.

According to a fourth aspect of the present invention, there is provided a method for adjusting a temperature of a superconducting coil device, comprising the steps of:
Since the superconducting coil is cooled from around room temperature by flowing the refrigerant from the side of the shield through the cooling pipe to the cooling pipe, even if the temperature of the radiation shield is higher than the temperature of the refrigerant,
The superconducting coil can be efficiently cooled in a short time.

According to a fifth aspect of the present invention, there is provided a method for adjusting a temperature of a superconducting coil device, comprising the steps of:
The superconducting coil was heated by flowing a high-temperature fluid from the side of the shield penetration to the cooling pipe.
The temperature of the superconducting coil can be evenly increased while preventing thermal distortion from remaining in the superconducting coil.

[Brief description of the drawings]

FIG. 1 is a configuration diagram showing a superconducting coil device according to Embodiment 1 of the present invention.

FIG. 2 is a sectional view of a main part of FIG.

FIG. 3 is a fragmentary cross-sectional view of a superconducting coil device according to a second embodiment of the present invention.

FIG. 4 is a configuration diagram showing a superconducting coil device according to Embodiment 3 of the present invention.

FIG. 5 is a relationship diagram showing a calculation example of a temperature rise of a superconducting coil and a radiation shield when the refrigerator of FIG. 4 is stopped.

FIG. 6 is a configuration diagram illustrating an example of a conventional superconducting coil device.

[Explanation of symbols]

1 vacuum vessel, 2 superconducting coil, 3 radiation shield,
Reference Signs List 4 refrigerator, 11 cooling pipe, 11a first shield penetration part, 11b second shield penetration part, 13 heat exchanger, 21 cold storage member.

Claims (5)

[Claims] 1. A vacuum container, a superconducting coil housed in the vacuum container, a radiation shield provided around the superconducting coil in the vacuum container, and a conductive member for conducting the superconducting coil and the radiation shield. And a cooling pipe whose both ends are drawn out of the vacuum vessel and whose middle part is in thermal contact with the superconducting coil, wherein the cooling pipe is not thermally contacted. A superconducting coil device comprising: a first shield penetration portion penetrating the radiation shield in a state; and a second shield penetration portion penetrating the radiation shield in a thermal contact state. 2. The cooling pipe in the second penetration portion includes:
The superconducting coil device according to claim 1, further comprising a heat exchanger. 3. A vacuum vessel, a superconducting coil housed in the vacuum vessel, a radiation shield provided around the superconducting coil in the vacuum vessel, and conducting through the superconducting coil and the radiation shield. 1. A superconducting coil device comprising: a refrigerator cooled by a cooling device; and a cold storage member that is in thermal contact with the radiation shield. 4. A vacuum vessel, a superconducting coil housed in the vacuum vessel, a radiation shield provided around the superconducting coil in the vacuum vessel, and a conductor for conducting the superconducting coil and the radiation shield. And a cooling pipe whose both ends are drawn out of the vacuum vessel and whose middle part is in thermal contact with the superconducting coil, wherein the cooling pipe is not thermally contacted. The method for adjusting the temperature of a superconducting coil device, comprising: a first shield penetration portion penetrating the radiation shield in a state; and a second shield penetration portion penetrating the radiation shield in a thermal contact state. 1. A method for adjusting the temperature of a superconducting coil device, wherein the superconducting coil is cooled from around room temperature by flowing a coolant from the side of the shield penetration portion to the cooling pipe. 5. A vacuum vessel, a superconducting coil housed in the vacuum vessel, a radiation shield provided around the superconducting coil in the vacuum vessel, and a conductor for conducting the superconducting coil and the radiation shield. And a cooling pipe whose both ends are drawn out of the vacuum vessel and whose middle part is in thermal contact with the superconducting coil, wherein the cooling pipe is not thermally contacted. The method for adjusting the temperature of a superconducting coil device, comprising: a first shield penetration portion penetrating the radiation shield in a state; and a second shield penetration portion penetrating the radiation shield in a thermal contact state. 2. A method for adjusting the temperature of a superconducting coil device, wherein the temperature of the superconducting coil is raised by flowing a high-temperature fluid from the side of the shield penetration portion to the cooling pipe.