JPH03240206A - Quench prevention of superconductive coil and applicable bobbin to the prevention - Google Patents

Abstract

PURPOSE:To efficiently prevent the quenching of superconductive coil from occurring by a method wherein the cooling down process feeding a cooling down refrigerant of coil winding and impregnating process of the winding are simultaneously applied to a passageway made in a bobbin near the contact surface between the bobbin and a coil winding. CONSTITUTION:A superconductive coil is provided with a bobbin 11 and a coil winding 12 comprising a superconductive material wound up around the outer periphery of the bobbin 11. A passageway 13 is made near the contact surface between the bobbin 11 and the coil winding 12 in the bobbin 11. The passageway 13 is composed of multiple hollow pipes 13 formed along the axial direction of the bobbin 11. The part wound up with the coil winding 12 is covered with an impregnating case 14 which is vacuumized and after impregnating the winding 12 with an impregnant filled in the case 14, the impregnating case 14 is removed. The coil winding 12 is cooled down by feeding the hollow pipes 13 with a cooling down refrigerant such as liquid He, etc. Through these procedures, the quenching of the superconductive coil can be prevented from occurring by simultaneously applying both of the impregnating process and the cooling down process to the passageway 13.

Description

[Detailed description of the invention] [Industrial application field] The present invention relates to a method for preventing quenching of a superconducting coil.

[Conventional technology]

As is well known, a superconducting coil includes a winding frame and a coil winding made of a superconducting material wound around the outer periphery of the winding frame.

Superconducting coils require several important considerations in order to maintain a stable superconducting state.

One of them is the need to prevent the occurrence of quench.

This quench occurs when the coil winding moves due to the electromagnetic force that occurs when a large current is passed through the superconducting coil, causing the coil winding to heat up due to frictional heat generated at the contact surface between the winding frame and the coil winding. This occurs when the critical current value decreases or the temperature of the coil winding rises above the critical temperature. As is well known in this field, the location where this quench occurs is where the winding frame and the coil winding touch, that is, the innermost number of the coil winding layers.

Conventionally, two methods have been adopted to prevent the occurrence of quenching: (1) cooling method and (2) impregnation method, which will be described in detail below.

■Cooling method As mentioned above, quenching occurs in the innermost shell of the coil winding layer, so in order to prevent quenching from occurring, the innermost shell should be sufficiently cooled with a cooling refrigerant. Conventionally, as shown in FIGS. 5 and 6, a groove member 1 has cooling grooves 15a formed on the outer periphery of a winding frame 11 around which a coil winding 12 is wound.
Install 5.

As shown in FIG. 7, the superconducting coils are efficiently cooled by flowing a cooling refrigerant such as liquid helium along the cooling grooves 15a.

■Impregnation method In this method, the coil winding is wound around the outer circumference of the winding frame to prevent the coil winding from moving, and then the coil winding is impregnated with an impregnating material such as resin to increase the coil rigidity. It is.

[Problem to be solved by the invention]

Consider the combination of the above-mentioned impregnation method and the conventional cooling method. In this case, if the coil winding is impregnated with an impregnating material,
Since the cooling grooves are filled with impregnating material, cooling cannot be performed effectively. Therefore, conventionally, only one of the impregnation method and the cooling method can be employed. However, it is clear that if both the impregnation method and the cooling method can be performed simultaneously, the occurrence of quenching can be more effectively prevented.

Therefore, an object of the present invention is to provide a method for preventing quenching of a superconducting coil, which allows both the impregnation method and the cooling method to be carried out simultaneously.

[Means to solve the problem]

A method for preventing quenching of a superconducting coil according to the present invention is a method for preventing quench occurring in a superconducting coil having a winding frame and a coil winding made of a superconducting material wound around the outer periphery of the winding frame, the method comprising: A step of flowing a cooling refrigerant for cooling the coil winding through a passage provided in the winding frame near a contact surface where the frame and the coil winding contact, and impregnating the coil winding with an impregnating material. and a step of doing so.

The superconducting coil winding frame used to realize the above-mentioned quench prevention method has a passage for flowing a cooling refrigerant inside near the contact surface with the coil winding where the coil winding is to be wound. has been done.

〔Example〕

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

Referring to FIG. 1, a superconducting coil to which the quench prevention method of the present invention is applied has a winding frame 11 and a coil winding 12 made of a superconducting material wound around the outer periphery of this winding frame 11. Inside the winding frame 11, there are the winding frame 11 and the coil winding 12.
A passage 13 is formed near the contact surface where the two contact each other.

The passage 13 in this embodiment is composed of a plurality of hollow pipes formed along the axial direction of the winding frame 11. The part where the coil winding 12 is applied is covered with the impregnating case 14, and the impregnating case 1
4 is in a vacuum state, an impregnating material made of, for example, epoxy resin is injected into the impregnation case 14, and the coil winding 12 is injected into the impregnation case 14.
After impregnating, the impregnation case 14 is removed.

A cooling refrigerant such as liquid helium is passed through the hollow pipe 13 to cool the coil winding 12 .

In this way, in the present invention, both the impregnation method and the cooling method are implemented simultaneously to prevent the occurrence of quenching of the superconducting coil.

Next, a method for manufacturing the winding frame 11 shown in FIG. 1 will be described with reference to FIGS. 2 to 4.

In order to form the passage 13 in the winding frame 11, it is necessary to perform machining to form a hole in the winding frame 11.

However, when the diameter of this hole becomes larger than 0.5 to 1.0 mm, the mechanical strength of the winding frame 11 decreases.

On the other hand, the diameter is 0.5 to 1. When machining to form Omm holes, it is very difficult to form deep holes. That is, the limit is to provide a through hole in a thick plate of approximately 5 to 10 mm. Therefore, it is not possible to machine through holes in the axial direction in the winding frame 11 of a normal superconducting coil having a length longer than 5 to 10 mm at once.

Therefore, as shown in FIG. 2, the winding frame 11 has a wall thickness of 5.0 to 10.0 mm, which allows for through-hole processing. Round cutting is performed on a plurality of round cutting plates 11a of CI+m. A predetermined number of holes 13a having a diameter of 0.5 to 1.0 m+e are formed in each of the plurality of round plates 11a by machining.

Referring to FIG. 3, the circular cut plate 11a after the hole forming process has been completed.
Stack the required number of sheets so that they overlap each other's holes 13a,
Assemble to a thickness that matches the required coil length.

Referring to FIG. 4, a hollow pipe 13 is passed through the axial hole 13a of the assembled winding frame 11, and hot isostatic pressure treatment (HIP) is performed to produce an integrated winding frame 11.

〔Effect of the invention〕

As explained above, according to the present invention, a cooling method in which a cooling refrigerant for cooling the coil winding is caused to flow through a passage provided in the winding frame near the contact surface where the winding frame and the coil winding come in contact with each other. By simultaneously implementing both the method of impregnating the coil winding with an impregnating material, it is possible to efficiently prevent the occurrence of quenching of the superconducting coil.

Margin below

[Brief explanation of drawings]

FIG. 1 is a sectional view showing the structure of a superconducting coil for realizing a quench prevention method according to an embodiment of the present invention, and FIGS. 2 to 4 are winding frames constituting the superconducting coil shown in FIG. 1. FIGS. 5 to 7 are diagrams for explaining a method for preventing quenching using a conventional cooling method. 11... Winding frame, lla... Ring cutting plate, 12... Coil winding, 13... Passage (hollow pipe), 13a...
Hole, 14... Case for impregnation. Figure 5 Figure 6

Claims (1)

[Claims] 1. A method for preventing quench occurring in a superconducting coil having a winding frame and a coil winding made of a superconducting material wound around the outer periphery of the winding frame, the method comprising: a step of flowing a cooling refrigerant for cooling the coil winding through a passage provided in the winding frame near a contact surface that contacts the coil winding; and a step of impregnating the coil winding with an impregnating material. A method for preventing quenching of superconducting coils. 2. A winding frame for a superconducting coil, in which a passage for flowing a cooling refrigerant is formed inside near the contact surface with the coil winding around which the coil winding is to be wound.