JPS5928042B2 - superconducting coil - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention generally relates to a superconducting coil that generates a high magnetic field, and particularly to the structure of a large superconducting coil used in a nuclear fusion device or the like.

Generally, superconducting coils are often used as devices that generate high magnetic fields, but unlike ordinary electromagnets, superconducting coils need to be cooled to extremely low temperatures, mainly liquid helium temperatures, and even more than mega joules, especially nuclear fusion. For the large superconducting coils that are expected to be used in devices that have magnetic field energy of more than kilojoules, it is important to construct a support structure that can withstand the huge electromagnetic force generated by the coils. This has become a problem, and the following methods have been developed in the past.

FIG. 1 is a sectional view showing the structure of a conventional superconducting coil group. In the figure, reference numeral 1 denotes a superconducting coil which is assembled by tightening bolts 2 and nuts 3 to form a superconducting coil group 100.

FIG. 2 is a perspective view showing the structure of the superconducting coil 1 in FIG. 1.

In the figure, reference numeral 4 denotes a plate-shaped holding member made of metal or an insulator, and a plurality of coil grooves 4a are provided on both sides.

A superconducting material 5 is housed in the coil groove 4a, and the space around it is filled with a cooling medium 6 such as liquid helium.

Reference numeral 7 denotes a spacing member having a cooling medium passage Ta that holds the superconducting material 5.

Note that when the holding member 4 is made of metal, this spacing member 7 is an insulating material or a metal whose surface has been subjected to insulation treatment.
If it is an insulator, it may be an insulator or a metal. These 4, 4a, 5, 6, 7, and Ta constitute the superconducting coil 1. In the superconducting coil 1 configured as described above, the superconducting material 5 is formed in the coil groove 4a provided in the holding member 4.
is held by the spacing member 7 so that its periphery is in contact with the cooling medium 6, so that the coil can withstand a huge electromagnetic force, and the stabilizing current can be increased by increasing the cooling surface area, which reduces the coil operating current. can bring about an increase in

In this case, the superconducting material 5 is cooled to a predetermined temperature by the cooling medium 6, but the excitation of the superconducting coil 1,
During demagnetization or when an external alternating magnetic field is applied, the superconducting material 5 may generate some heat and the cooling medium 6 may evaporate and generate bubbles, so a cooling medium passage 7a is provided in the spacing member 7.
is installed to allow the air bubbles to escape. However, the bubbles generated in the first section shown in the figure pass through the cooling medium passage 7a, combine with the bubbles generated in the second section, become larger, and further enter the next section, and the large bubbles enter the superconducting material 5.
It adheres to the coil, impairing the cooling effect and lowering the coil stabilizing current. In addition, if the stabilizing current decreases, the operating current must also decrease, so if the same magnetic field is to be generated in the same space, the coil must be larger, resulting in a larger device. Ta. This invention has been accomplished with the aim of eliminating the drawbacks of the above-mentioned conventional devices.

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of a superconducting coil according to the present invention will be described in detail below with reference to the drawings.

FIG. 3 is a perspective view showing the structure of an embodiment of a superconducting coil according to the present invention.

In the figure, the holding member 4, the coil groove 4a1, the superconducting material 5, and the cooling medium 6 are the same as those of the conventional ones, so their explanation will be omitted.

Reference numeral 8 denotes a spacing member provided in the coil groove 4a, and the superconducting material 5
hold.

Reference numeral 9 denotes a cooling medium passage formed in the holding member 4, which communicates with each section partitioned by the spacing member 8 via a branch passage 9a, and discharges bubbles generated in the cooling medium 6 to the outside.

These 4, 4a, 5, 6, 8, 9, and 9a constitute a superconducting coil 10. As mentioned above, in the superconducting coil 10 configured as shown in FIG. 3, as in the conventional superconducting coil 1, the superconducting material 5 generates a slight amount of heat when the superconducting coil 10 is excited or demagnetized or when an alternating current magnetic field is applied from the outside. This causes the cooling medium 6 to evaporate and generate bubbles.
Since the sections partitioned by the spacing members 8 are each independently connected to the cooling medium passage 9 by the branch passages 9a, air bubbles generated in a single section are removed by the branch passages 9a in that section. There is no possibility that the cooling effect of the superconducting material 5 in other sections will be deteriorated.

FIG. 4 is a perspective view showing the structure of another embodiment of the superconducting coil according to the present invention.

In the figure, the holding member 4, the coil groove 4a1, the superconducting material 5, the cooling medium 6, the spacing member 8, and the cooling medium passage 9 are the same as those of the superconducting coil 10 in FIG. 3, so a description thereof will be omitted.

Reference numeral 9b denotes a branch passage communicating with the section partitioned by the spacing member 8 from the cooling medium passage 9, and is formed obliquely along the rising direction of the bubbles, that is, not perpendicular to the cooling medium passage 9 and the coil groove 4a. ing.

These 4, 4a, 5, 6, 8, 9, and 9b constitute a superconducting coil 20. Now, if the amount of bubbles passing through the cooling medium passage 9 in the superconducting coil 10 in FIG. However,
Branch 9 as in superconducting coil 20 in FIG.
By forming b obliquely, it is possible to eliminate the above-mentioned risk of damage.

In summary, the present invention improves the cooling effect of the cooling medium of the superconducting material and increases the coil stabilizing current by forming a passage to take out the air bubbles in the cooling medium generated by heat generation of the superconducting material of the superconducting coil to the outside. This results in an increase in coil operating current.

When generating the same magnetic field in the same space, this has the effect of making the coil more compact, as well as the cryostat and cooling system, making it easier to create large superconducting coils for nuclear fusion devices, superconducting rotating machines, etc. The practical effect is tremendous in that it can be manufactured compactly.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view showing the configuration of a conventional superconducting coil group;
FIG. 2 is a perspective view showing the configuration of the superconducting coil in FIG. 1, FIG. 3 is a perspective view showing the configuration of one embodiment of the superconducting coil in this invention, and FIG. 4 is another embodiment of the superconducting coil in this invention. FIG. 2 is a perspective view showing an example configuration. In the figure, 1 is a superconducting coil, 2 is a bolt, 3 is a nut, 4 is a holding member, 4a is a coil groove, 5 is a superconducting material, 6 is a cooling medium, 7 is a spacing member, 7a is a cooling medium passage, 8 is a spacing member , 9 is a cooling medium passage, 9a, 9b are branch passages, 10,
20 is a superconducting coil.

Claims (1)

[Scope of Claims] 1 A holding member having a coil groove on at least one side surface, a superconducting material housed in the coil groove, and a spacing member that holds the superconducting member at a distance from the holding member, The holding member includes a groove provided parallel to the coil groove between the coil grooves, and at least one branch groove communicating the coil groove and the groove in a section partitioned by the adjacent spacing member. , for filling the groove and the coil groove with a medium for cooling the superconducting material and discharging air bubbles generated in the medium in the coil groove through the branch groove and groove. Characteristic superconducting coil. 2. The superconducting coil according to claim 1, wherein the branch grooves are formed not to be perpendicular to the grooves.