JPH0135482B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a superconducting magnet, and more particularly to a superconducting magnet device with improved superconducting stability and cooling performance.

Conventionally, many superconducting magnets have been of the forced cooling type consisting of bundled conductors.
Figures a and b show its general configuration. First, Figure 1a is a cross-sectional view of a forced cooling type superconducting magnet including the support container at a temperature of 4.2〓, and Figure 1b is
1A shows the detailed structure of the bundle conductor in the "A" section in FIG. 1a. Note that the 80° liquid nitrogen-cooled radiation shield and the vacuum insulation container are not shown in the figure. In the figure, reference numeral 1 indicates a bundle conductor, and this bundle conductor 1 has a superconducting winding 3 housed in a cable shape inside a metal cylinder 2, and a gas or liquid helium cooling medium is used as the bundle conductor 1, as shown in Figure b. (hereinafter referred to as a refrigerant) by forced cooling. Further, after applying a turn insulator 4 to this bundle conductor 1, it is wound as a magnet, and then a ground insulating part 5 is applied to the entire outer surface of the magnet. Thereafter, a support structure container 6 is attached to the magnet in order to reduce the electromagnetic force acting on the magnet.

Unlike conventional hollow superconducting conductors, a superconducting magnet with such a configuration uses a bundle conductor made of superconducting thin wires, so the contact area with the helium coolant can be easily increased and effective cooling can be achieved. Furthermore, since the magnet has a forced cooling structure, it is mechanically robust.

However, since such a forced cooling type superconducting magnet literally has a forced cooling structure, it is necessary to circulate a helium coolant in an extremely low temperature state. Although the development of helium circulation pumps for this purpose is progressing, the current situation is that their processing capacity is still small and further development is required. In addition, in the forced cooling type superconducting magnet as described above, the power of the pump required for circulating helium is expressed by the following equation. However, the pump efficiency is 70%.

P=ΔP・m〓(watts) Here, ΔP: Pressure loss in helium circulation (atm) m〓: Mass flow rate of helium (g/s) In this case, the value shown in the above equation is This corresponds to a refrigeration load, and when converted into electric power, it requires about 500 times this amount, resulting in a huge power loss, which negates the advantage of superconducting magnets, which is zero module loss.

The present invention was made in view of the above circumstances, and its purpose is to significantly improve cooling performance and superconducting stability without requiring a pump for circulating gaseous or liquid helium refrigerant, and without power loss due to circulation. The object of the present invention is to provide an immersion-cooled superconducting magnet device that can be improved in terms of performance.

Therefore, the present invention provides a bundle conductor in which a large number of superconducting thin wires are housed in a cable shape and wound into a coil shape inside a metal cylinder having a plurality of through holes for cooling medium circulation formed in the peripheral surface thereof, and A structure comprising a turn insulator in which a through hole for cooling medium circulation is formed at a position coinciding with a through hole provided in a metal cylinder, and a container for accommodating the bundle conductor, the turn insulator, and the cooling medium. The aim is to achieve the above objectives.

An embodiment of the present invention will be described below with reference to the drawings.

FIGS. 2a and 2b are sectional views showing an example of the configuration of a superconducting magnet device according to the present invention, and FIG. 2b shows a detailed configuration of the "B" portion in FIG. 2a. In the figure, reference numeral 8 denotes a metal tube made of metal having a rectangular cross-section, in which thin superconducting wires 9 are accommodated in the form of a cable as shown in the figure, forming a bundle conductor 7. Further, reference numeral 10 denotes a turn insulator made of a glass laminated plate or the like applied to the entire outer circumferential surface (only one side in the figure) of the metal tube 8, and this turn insulator 10 and the metal tube 8 are provided with a shape as shown in the figure. A plurality of circular refrigerant flow through holes 11 whose positions coincide with each other are provided. Furthermore, the bundle conductor 7 having a shape similar to the hollow conductor constructed as described above is wound into a pancake shape with a cooling spacer 12 as a layer insulator in between as shown in the figure to form a magnet, and this is used as a refrigerant, for example. It is constructed by being housed in a liquid helium container 13 containing liquid helium (or gaseous helium).

With such a configuration, the bundle conductor 7 having a similar shape to the hollow conductor is connected to the turn insulator 10 as described above.
Since the bundle conductor 7 is wound in a coil shape through the conductor bundle 7, the insulation of the bundle conductor 7 is maintained, and the inside and outside of the bundle conductor 7 are immersed and cooled by liquid helium as a coolant. In other words, liquid helium can freely flow between the inside and outside of the bundle conductor 7 through the entire circumferential surface of the metal cylinder 8 and the through holes 11 provided in the turn insulator 10, and its cooling effect is normally A similar immersion cooling magnet is obtained. However, in this embodiment, a bundle conductor 7 made up of superconducting thin wires 9 housed in a metal cylinder 8 is used as the conductor, so the cooling surface area becomes very large, and the cooling performance is greatly improved, compared to the normal one. Superconducting stability can be significantly improved compared to conductors. In addition, since the metal cylinder 8 and the turn insulator 10 are configured to have the through holes 11 as described above, sufficient cooling effect can be achieved without forced circulation of helium coolant, unlike in conventional forced cooling type superconducting magnets. Since a pump for circulation is not required, it is possible to eliminate the enormous power consumption required for circulation, and it is extremely economical in terms of energy saving. That is, with the established technology of the immersion cooling method, it is possible to obtain a superconducting magnet using bundled conductors, and its reliability can be greatly improved.

Furthermore, since liquid helium flows in each direction through each through hole, even if the metal cylinders housing the bundle conductors are arranged vertically and horizontally, liquid helium flows through these metal cylinders and cooling is similarly achieved. It will be done. Note that the present invention is not limited to the above-mentioned embodiment, and may be modified without departing from the spirit thereof. For example, each through hole is not limited to a circular shape, and may have any shape.

As explained above, according to the present invention, a large number of superconducting thin wires are housed in a cable shape and wound into a coil shape inside a metal cylinder having a plurality of through holes for cooling medium circulation formed in the peripheral surface. a bundle conductor, a turn insulator having a through hole for circulating a cooling medium formed at a position corresponding to a through hole provided in the metal cylinder, and housing the bundle conductor, turn insulator, and cooling medium. The structure includes a container, which eliminates the need for a pump for circulating the cooling medium, eliminates power loss due to circulation, and is highly reliable, greatly improving cooling characteristics, superconducting stability, and economic efficiency. A superconducting magnet device can be provided.

[Brief explanation of drawings]

1A and 1B are sectional views showing the structure of a conventional forced cooling type superconducting magnet, and FIGS. 2A and 2B are sectional views showing an embodiment of the present invention. 7...Bundle conductor, 8...Metal tube, 9...Superconducting thin wire, 10...Turn insulator, 11...Through hole, 1
2... Cooling spacer, 13... Liquid helium container.

Claims (1)

[Claims] 1. A bundle conductor in which a large number of thin superconducting wires are housed in a cable shape and wound into a coil shape inside a metal cylinder having a plurality of through holes for cooling medium circulation formed in the peripheral surface thereof, and the metal cylinder The conductor is characterized by comprising a turn insulator having a through hole for circulating a cooling medium formed at a position that coincides with the through hole provided in the conductor, and a container for accommodating the bundle conductor, the turn insulator, and the cooling medium. Superconducting magnet device.