JPS6351524B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Technical Field of the Invention] The present invention relates to a superconducting magnet, and more particularly to a superconducting magnet with improved fixing means for superconducting coils.

[Technical background of the invention]

Generally, in order to ensure stable operation of a superconducting magnet, it is necessary to keep the superconducting coil, which is the main part of the superconducting magnet, in a superconducting state at all times. In other words, a coolant such as liquid helium is passed around the superconducting coil in order to cool the superconducting wire that forms the superconducting coil to below the normal conduction transition temperature and to prevent distortion of the superconducting wire due to the electromagnetic force generated when electricity is applied. In addition to cooling the superconducting coil by increasing the rigidity of the support that supports the superconducting coil, consideration is given to preventing distortion from occurring in the superconducting wire that forms the superconducting coil.

FIG. 1 is a cross-sectional view showing a main part of an example of a superconducting magnet in which the above-mentioned measures have been taken. That is, a molded superconducting coil 2 manufactured by soaking it in an impregnating material such as resin to improve rigidity is housed in a cryocase 1 containing a refrigerant, and this superconducting coil 2 is spacers 4a, 4b, 4c, 4d inserted between the inner surface 3 of the cryo case 1 and the recesses 5 formed on the inner surfaces 3 of both side walls of the cryo case 1;
The superconducting coil 2 is fixed by a support member 6 fitted into and fixed to the superconducting coil 2, and another spacer 7 inserted between the support member 6 and the superconducting coil 2.

As a means for improving the rigidity of the superconducting coil, in addition to the above-described configuration, a method in which the outer circumferential surface of the superconducting coil is wrapped and fixed with stainless steel wire is also being considered.

[Problems with background technology]

However, the superconducting magnet constructed as described above has the following problems.

In other words, even if it is a molded superconducting coil or a superconducting coil reinforced with stainless steel wire, when the superconducting coil is cooled with a refrigerant, the superconducting wire that makes up the superconducting coil will undergo thermal contraction, and the superconducting coil will become superconducting. A gap is created between the coil and the spacer. When a gap is created in this way, the superconducting coil is in a state where it is relatively easy to move within the cryocase, and when a current is passed through the superconducting coil in this state, a large strain is generated in the superconducting wire due to electromagnetic force. As a result, a quench phenomenon occurs in which the superconducting state shifts to the normal conducting state, and there is a risk that stable operation may not be possible.
In particular, in a superconducting magnet in which two superconducting coils are disposed facing each other, a large electromagnetic force acts between the two superconducting coils, resulting in the problem that the above-mentioned distortion becomes even larger.

Therefore, in order to eliminate such problems,
When using a molded superconducting coil as shown in Figure 1, it is conceivable to increase the amount of impregnating material and cover the superconducting coil with a thick coating layer in order to improve the rigidity of the coil. , the distance between the superconducting wire and the refrigerant increases,
Since the cooling effect is reduced, there is a problem in that the amount of liquid helium used for cooling must be increased.

[Purpose of the invention]

The present invention has been made in view of these circumstances, and its purpose is to have a simple configuration,
The cryocase and the superconducting coil can be more firmly integrated, and as a result, the rigidity of the superconducting coil can be increased.
The object of the present invention is to provide a superconducting magnet that has excellent resistance to electromagnetic force and is stable in operation, thereby improving operating efficiency.

[Summary of the invention]

In the superconducting magnet of the present invention, both end faces of a molded superconducting coil are supported between two opposing wall faces of a cryo case, and the above-mentioned wall part is supported between the two wall parts and both end faces of the superconducting coil. It is characterized in that spacers for forming refrigerant passages fixed with adhesive are interposed on the inner surface and both end faces of the coil, and the two walls are further tightened and fixed by a fastening mechanism.

〔Effect of the invention〕

With such a configuration, when a refrigerant such as liquid helium is passed around the superconducting coil to cool the superconducting coil, thermal shrinkage stress is applied to the superconducting wire constituting the superconducting coil, and the superconducting coil trying to shrink. However, both end faces of the superconducting coil are integrally fixed to the cryo case via an adhesive, a spacer, or an adhesive, and the two walls of the cryo case that sandwich the superconducting coil are fastened together using bolts, etc. Since the superconducting coil is tightened and fixed by the mechanism, even if the above-mentioned heat shrinkage stress is applied to the superconducting coil, there is no possibility that a gap will be created between the end face of the superconducting coil and the wall portion.
Therefore, since the superconducting coil does not move significantly due to electromagnetic force, no large strain occurs in the superconducting wire. Therefore, the occurrence of the quench phenomenon can be prevented.

In addition, since the superconducting coil and cryo case can be more firmly integrated, the rigidity of the superconducting coil and the cryo case can be improved, which allows the resin coating layer covering the coil to be made thinner. Not only can the amount of liquid helium required to cool the superconducting coil be reduced, but also the thickness of the cryocase can be made thinner, thereby making it possible to effectively utilize the generated magnetic field.

[Embodiments of the invention]

FIG. 2 is a perspective view showing a schematic configuration of a superconducting magnet according to an embodiment of the present invention, and FIG. 3 is a cross-sectional view taken along line A-A in FIG. 2 and viewed in the direction of the arrow. , FIG. 4 is a cutaway view taken along the line B-B and viewed in the direction of the arrow.

In the figure, reference numeral 11 denotes a cryocase formed of, for example, a stainless steel plate or the like in a substantially rectangular parallelepiped shape. A venting cavity 12 having an inverted T-shaped cross section is provided in the center of the cryocase 11. Due to the existence of this cavity 12, two air vents are formed inside the cryocase 11 as shown in FIG. Two flat coil housing portions 13a and 13b are formed in parallel. And in each coil storage part 13a, 13b,
Molded superconducting coils 14a and 14, respectively.
b are housed in such a manner that both end surfaces thereof are supported by side walls 15a, 16a and 15b, 16b constituting the coil housing portions 13a, 13b, respectively.

The superconducting coil 14a and the coil storage section 13a
As shown in FIG. 4, a spacer 18 having a spiral groove 17 on one side is provided between the side walls 15a and 16a constituting the superconducting coil 1.
Both end faces of the superconducting coil 14a and the side wall 15 are bonded to the end faces of the superconducting coil 14a with a cryogenic adhesive 19 toward the end face of the superconducting coil 14a.
a, 16a and are inserted in a bonded state. Note that the other superconducting coil 14b is similarly stored in the coil storage portion 13b.

Therefore, between the side walls 15a and 16a constituting the coil storage parts 13a and 13b, and
A plurality of bolts 20 are installed between the superconducting coils 14a and 16b at positions inside the superconducting coils 14a and 16b, respectively, to tighten the opposing side walls, and a spacer 28 is installed at the outside position. A plurality of bolts 29 are attached through the bolts. Furthermore, a connecting rod 21 for connecting the side walls described above is installed in the space above the coil storage portions 13a and 13b in the drawing. Further, a lid 22 is attached to the upper open end of the coil storage parts 13a, 13b to cover them in common, and a liquid helium 22 is placed in the center of the lid 22 to cover the coil storage parts 13a, 13b. An injection port 24 is provided for injecting.

In addition, 25 and 26 in the figure are the above-mentioned coil storage part 1.
These are bolts and spacers for reinforcing the side walls 15a, 15b of 3a, 13b.

In the superconducting magnet constructed as described above, when liquid helium 23 is injected into the coil storage parts 13a, 13b from the injection port 24, the liquid helium 23 flows through the grooves 17 of the spacer 18 and flows into the superconducting coils 14a, 14b. It also flows inside. When the coil storage parts 13a and 13b are filled with liquid helium 23, the outer surfaces, inner surfaces and both end surfaces of the superconducting coils 14a and 14b completely contact the liquid helium 23, so that the superconducting coils 14a and 14b are completely in contact with the liquid helium 23. , 14b are cooled to a superconducting state. In this state, the superconducting coil 14
By passing an energizing current through a and 14b and switching it to persistent current mode, each superconducting coil 1
A continuous high magnetic field can be generated at 4a and 14b.

In this case, as described above, the side wall 15
A, 16a and 15b, 16b are tightened using a fastening mechanism such as a bolt, and the superconducting coil 14
Adhesive 19 to spacer 18 on both end surfaces of a and 14b
- Since the superconducting coils 14a and 14b are fixed to the corresponding side walls via the adhesive 19, the superconducting coils 14a and 14b and the corresponding side walls 15a, 16a, 15b and 16b can be completely mechanically integrated. Therefore, even if the superconducting coils 14a, 14b are cooled to near zero absolute temperature as described above, the superconducting coils 14a, 14b and the side walls 15a, 16a, 1
5b and 16b will not form a gap. Therefore, the superconducting coils 14a, 1
Force F due to the magnetic field shown by arrow 27 in FIG. 3 between 4b
Even when the superconducting coil 1
Since 4a and 14b do not move significantly, there is no possibility that a large strain will occur in the superelectric wire, and therefore, the occurrence of the quench phenomenon can be prevented and stable operation can be performed.

In addition, as described above, superconducting coils 14a, 14
b and each side wall can be firmly integrated, and as a result, the rigidity of the superconducting coils 14a, 14b can be increased. Therefore, since the thickness of the resin coating layer of the superconducting coils 14a and 14b can be reduced, liquid helium 2 for cooling can be reduced.
It is possible to reduce the usage amount of 3. Therefore, operating costs can be reduced and stable operation can be achieved.

Furthermore, the coil storage section 1 of the cryo case 11
Since the overall structure of 3a and 13b is a sandwich structure in which the superconducting coil is sandwiched between side walls, the strength will not be significantly reduced compared to conventional devices even if the side walls etc. are made thin like a honeycomb structure. .
Therefore, since the superconducting coil can be brought closer to other equipment, the generated magnetic field can be used more efficiently, and the above-mentioned effects can be obtained after all.

[Brief explanation of the drawing]

FIG. 1 is a sectional view showing the main parts of a conventional superconducting magnet, FIG. 2 is a partially cutaway schematic perspective view of a superconducting magnet according to an embodiment of the present invention, and FIG. 2 is a cross-sectional view taken along the line A--A and viewed in the direction of the arrow, and FIG. 4 is a cross-sectional view similarly taken along the line B--B and viewed in the direction of the arrow. 11...Cryocase, 12...Cavity, 13
a, 13b...Coil storage section, 14a, 14b...
...Superconducting coils, 15a, 15b, 16a, 16
b... Side wall, 17... Groove, 18, 26, 28...
Spacer, 19... Adhesive, 20, 25, 29...
...Bolt, 22...Lid, 23...Liquid helium, 24...Inlet.

Claims (1)

[Claims] 1 A cryocase in which a refrigerant is stored,
A resin-molded superconducting coil is housed in the cryocase in such a manner that both end faces thereof are supported by the two opposing walls of the cryocase, and both end faces of the superconducting coil and the two walls are supported by the two opposing walls of the cryocase. A pair of refrigerant passage forming spacers interposed between the two walls and fixed with adhesive to the inner surfaces of the two walls and both end surfaces of the superconducting coil, and applying a tightening force between the two walls. A superconducting magnet characterized by comprising a fastening mechanism.