JPH0335810B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a cooling method for electrical equipment, and in particular,
The present invention relates to a method for cooling electrical equipment such as a superconducting coil housed in a container using a cooling liquid.

[Prior Art] FIG. 2 is a diagram showing an example of a conventional method for cooling a superconducting coil. In FIG. 2, superconducting coil 1 is immersed in liquid helium 4 in helium container 2. In FIG. The helium container 2 is housed in a vacuum container 3 to prevent heat from entering from the outside. Then, liquid helium 4 is injected from the inlet pipe 5 to cool the superconducting coil 1. On the other hand, helium vapor generated within the helium container 2 is discharged to the outside from the outlet pipe 6.

[Problems to be Solved by the Invention] In the method for cooling the superconducting coil 1 as shown in FIG. 2 described above, slipping occurs between the coils of the superconducting coil 1 due to the electromagnetic force acting on the superconducting coil 1. When such slipping occurs, a large amount of liquid helium 4 evaporates in a short time due to heat generation due to friction, and as a result, the liquid level rises. As the liquid level rises, the pressure inside the helium container 2 increases, and the liquid helium 4 flows out from the outlet pipe 6 and the inlet pipe 5 as a two-phase flow in which liquid and gas are mixed. That is, as the pressure inside the helium container 2 increases, liquid helium 4 is no longer injected from the inlet pipe 5, and the inside of the helium container 2 is almost in an evaporative state, and the superconducting coil 1 is no longer cooled. For this purpose, superconducting coil 1
The temperature of the superconductor increases, exceeding the critical temperature, and the superconductor transforms into a normal conductor, potentially generating a large amount of Joule heat generation. In this way, when the superconducting coil 1 is immersed in the liquid helium 4, the pressure rise when the above-mentioned disturbance occurs is large, making it difficult to control the flow rate.

Therefore, the main purpose of this invention is to create a liquid film on the surface of electrical equipment such as a superconducting coil, prevent pressure rise in the container, and effectively cool the electrical equipment. The goal is to provide the following.

[Means for Solving the Problems] The present invention is a cooling method for cooling an electrical device housed in a container having an inlet pipe and an outlet pipe.
The cooling liquid injected from the inlet pipe forms a liquid film on the surface of the electrical equipment, creating a vapor space between the container and the electrical equipment.

[Function] In the method for cooling electrical equipment according to the present invention, a liquid film is formed on the surface of the electrical equipment and the surrounding area is a vapor space, so that the amount of evaporation caused by thermal impact is absorbed in the vapor space. Therefore, pressure rise can be kept low. Accordingly, since the cooling liquid can be injected from the inlet pipe, the surface of the electrical equipment is cooled with a liquid film, and the temperature of the electrical equipment can be prevented from rising.

[Embodiment] FIG. 1 is a diagram showing an embodiment of the present invention.
In FIG. 1, a superconducting coil 1, a helium container 2, and a vacuum container 3 are constructed in the same manner as in FIG. 2 described above. The inlet pipe 5 is provided at the top of the helium container 2, and the outlet pipe 6 is provided at the bottom of the helium container 2. An appropriate amount of liquid helium 4 is injected from the inlet pipe 5, and the dropped liquid helium 4 forms a liquid film J on the surface of the superconducting coil 1. The superconducting coil 1 is cooled by the liquid film J of liquid helium 4, and a vapor space 7 is formed around it. When liquid helium 4 is injected from the inlet pipe 5, it flows from the upper surface of the superconducting coil 1 along the side surfaces, spreads to the lower surface, flows down, and flows out from the outlet pipe 6 as a two-phase flow with steam. The steam generated when a thermal impact acts on the superconducting coil 1 is absorbed into the surrounding steam space 7, so that the pressure rise can be suppressed to a low level.

Therefore, since liquid helium 4 can be constantly injected from the inlet pipe 5, the surface of the superconducting coil 1 is cooled by the liquid film J, and the temperature of the superconducting coil 1 is prevented from rising. Thereby, the risk of transition from a superconductor to a normal conductor when a disturbance occurs is greatly reduced.

In addition, in the above-mentioned embodiment, it was explained that the amount of liquid helium 4 injected was an appropriate amount, but this does not apply to the superconducting coil 1.
It is sufficient that the amount of liquid is such that a liquid film J is always formed on the surface of the liquid.

Further, although liquid helium 4 is used as an example for forming the liquid film, liquid nitrogen may be used depending on the composition of the superconducting coil 1.

Further, in the above-described embodiment, the method for cooling the superconducting coil 1 has been described, but the present invention is not limited to this, and can also be applied to the case of cooling a transformer around which a normal conductor coil is wound. In this case, oil may be used as the cooling liquid.

[Effects of the Invention] As described above, according to the present invention, the electrical equipment is cooled by forming a liquid film of cooling liquid around the electrical equipment, so that the pressure inside the container does not become abnormally high. Cooling can be performed reliably without any problems, and the cooling state can be accurately grasped, improving reliability. In addition, the amount of coolant required is reduced,
The scale of electrical equipment is also reduced, and costs can be reduced.

[Brief explanation of drawings]

FIG. 1 is a diagram for explaining one embodiment of the present invention. FIG. 2 is a diagram for explaining a conventional method of cooling a superconductor coil. In the figure, 1 is a superconducting coil, 2 is a helium container, 3 is a vacuum container, 4 is liquid helium, 5 is an inlet pipe, 6 is an outlet pipe, 7 is a vapor space, and J is a liquid film.

Claims (1)

[Claims] 1. A cooling method for cooling an electrical device housed in a container having an inlet pipe and an outlet pipe, the method comprising: forming a liquid film on the surface of the electrical device by a cooling liquid injected from the inlet pipe; A method for cooling electrical equipment, characterized by forming a vapor space between the container and the electrical equipment. 2. The method for cooling an electrical device according to claim 1, wherein the electrical device is a superconducting coil.