Insulation Wrapping Technology for Double Joint Box of High Temperature Superconducting Current Leads

Abstract

The invention discloses an insulation wrapping process for a high-temperature superconducting current lead double joint box, including the steps of wrapping the double joint box with a G10 insulation board and a glass felt impregnated with insulation glue. The invention can directly adopt an on-site glue coating wrapping method during wrapping, and cooperate with a room temperature curing process to ensure a high glue richness, a low insulation void ratio and a curing quality, and also avoid the occurrence of local glue shortage and uneven contour.

Description

Technical Field

[0001] The invention relates to the technical field of high-temperature superconductivity, and in particular to an insulation winding process for a double-joint box of a high-temperature superconducting current lead. Background Art

[0002] High-temperature superconducting current lead is one of the core components of the superconducting magnet feeder system of nuclear fusion device. During manufacturing, its double joint box needs to be insulated and wrapped. The current insulation wrapping scheme is to fill the inside of the double joint box with silicon micropowder, wrap the outside with prepreg tape, and then heat and cure. Its shortcomings are: ① The requirements for the contour after the double joint is overlapped are too high, and all corners are blunt angles and smooth transitions. Therefore, it is necessary to process the corresponding assembly parts according to the structure of the joint box to make the contour of the wrapping area smooth and uniform; ② Due to the high curing temperature of the glue, when wrapping at room temperature, a larger wrapping force is required to have a lower insulation porosity; ③ The double joint box is large in size, the material distribution is uneven, the overall contour is relatively complex, the thermal inertia is large, the overall heating temperature uniformity is difficult to grasp, and the temperature control is difficult, which will affect the insulation quality after curing; ③ At the curing temperature, the fluidity of the glue is greatly enhanced, and the glue will flow downward under the influence of gravity, resulting in a lack of glue in the upper area and poor contour. Summary of the invention

[0003] The object of the present invention is to provide an insulation wrapping process for a high-temperature superconducting current lead double joint box which can ensure lower insulation void ratio and curing quality and avoid the occurrence of local glue shortage and uneven contour.

[0004] A high-temperature superconducting current lead double joint box insulation wrapping process, the high-temperature superconducting current lead double joint box comprises a box body located at the end of the current lead, a U-shaped elbow is connected between the box bodies of two adjacent current leads, the box body comprises two plates arranged with a relative gap, screw holes are evenly distributed on both sides of the plate body along the height direction, the screws pass through the screw holes on the plate body correspondingly to achieve the connection between the plate bodies; a nut is sleeved on the end of the screw outside the screw hole, and a cavity for superconducting wires to pass through is formed between the two plate bodies and the screws on both sides;

[0005] The insulation wrapping process comprises the following steps:

[0006] (1) Place a G10 insulation board on the surface of the box body facing the U-bend pipe, and use glass felt impregnated with insulating glue to pile up a climbing section towards the U-bend pipe on the G10 insulation board;

[0007] (2) Place a G10 insulation board on the inner side of the cavity and fill the other gaps in the cavity with glass felt impregnated with insulating glue;

[0008] (3) Fill the gaps between the screws and the screw holes with glass felt impregnated with insulating glue;

[0009] (4) Place G10 insulation plates on the left, right, front and back of the box;

[0010] (5) Fill the cavity with glass felt impregnated with insulating glue on the surface of the box body facing the current lead, and then place the G10 insulating board on this surface, so that the G10 insulating boards on the six surfaces of the box body form a sealed state;

[0011] (6) On the G10 insulating board of the box body facing the current lead, use glass felt impregnated with insulating glue to pile up a climbing section towards the current lead;

[0012] (7) Curing at room temperature.

[0013] Since the present invention wraps the double joint box by using G10 insulation board and glass felt impregnated with insulation glue, the on-site glue coating and wrapping method can be directly adopted during the wrapping. Combined with the room temperature curing process, a high glue richness, a low insulation void ratio and a curing quality can be ensured, and the occurrence of local glue shortage and uneven contour can be avoided.

[0014] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0016] Figure 1 Schematic diagram of the structure of the high-temperature superconducting current lead (including double joint box) in this embodiment;

[0017] Figure 2 Schematic diagram of the structure of the box body (interior) in this embodiment;

[0018] Figure 3 Schematic diagram of the structure of the box body (exterior) in this embodiment. DETAILED DESCRIPTION

[0019] The preferred embodiments of the present invention are described in detail below in conjunction with the accompanying drawings so that the advantages and features of the present invention can be more easily understood by those skilled in the art, thereby making a clearer and more definite definition of the protection scope of the present invention.

[0020] See also Figure 1The present embodiment provides a high-temperature superconducting current lead double joint box insulation wrapping process, the high-temperature superconducting current lead double joint box comprises a box body 2 located at the end of the current lead 1, a U-shaped bend 3 is connected between the box bodies 2 of two adjacent current leads 1, and a Figure 2 The box body 2 includes two plates 21 with a relative gap, and screw holes 22 are evenly distributed on both sides of the plate body 21 along the height direction. The screws 23 pass through the screw holes 22 on the plate body 21 to achieve the connection between the plate bodies 21. The ends of the screws 23 outside the screw holes 22 are sleeved with nuts 24. The two plates 21 and the screws 23 on both sides form a cavity 25 for the superconducting wire 4 to pass through.

[0021] The insulation wrapping process comprises the following steps:

[0022] Combination Figures 1 to 3 ,

[0023] (1) Place a G10 insulating board 5 on the surface of the box body 2 facing the U-shaped bend 3, and use a glass felt soaked in insulating glue (the insulating glue is composed of epoxy resin and curing agent, and the solidification method is to stand and solidify at room temperature) on the G10 insulating board 5 to form a climbing section 6 facing the U-shaped bend 3;

[0024] (2) Place a G10 insulating plate 5 inside the cavity 25, and fill other gaps in the cavity 25 with glass felt soaked in insulating glue until all gaps are filled;

[0025] (3) Fill the gaps between the screws 23 and the screw holes 22 with glass felt impregnated with insulating adhesive;

[0026] (4) Place G10 insulating plates 5 on the left, right, front and back of the box body 2;

[0027] (5) On the surface of the box body 2 facing the current lead 1, fill the cavity 25 with glass felt soaked in insulating glue (fill it flat) and then place the G10 insulating board 5 on this surface, so that the G10 insulating boards 5 on the six surfaces of the box body 2 form a sealed state (polyimide tape can be used to assist in fixing during assembly);

[0028] (6) On the G10 insulating board 5 of the box body 2 facing the current lead 1, use glass felt impregnated with insulating glue to pile up a climbing section 6 in the direction of the current lead 1 to facilitate the later insulation wrapping;

[0029] (7) Curing at room temperature.

[0030] Since G10 insulation board is used in combination with wrapping materials such as glass felt impregnated with insulating glue, on-site glue coating and wrapping can be directly adopted during manufacturing, combined with room temperature curing process (wet wrapping), which has the following advantages: ① The on-site coating method can ensure a high amount of glue, so that too much wrapping force and a large wrapping space are not required, and a low insulation void ratio can be ensured; ② Since it is cured at room temperature, there is no problem of uneven heat, and the curing quality can be guaranteed; ③ As time goes by, the fluidity of the glue becomes worse and worse, and the influence of external interference factors will become lower and lower, thus avoiding the situation of local glue shortage and poor contour; ④ The requirements for the wrapping section are not high, and heterogeneous sections can be filled with glass felt with glue to create a smooth transition.

[0031] Specifically, the structure of the double joint box has a square overlap area. The area connecting the superconducting cable changes from square to round (extremely small diameter), with a large diameter change. It is wrapped with pre-impregnated tape, which is easy to produce a high void ratio and local glue shortage. Although the outer diameter of the current lead area is similar, it is still impossible to use a larger wrapping force (easy to slip) when changing from square to round, resulting in insulation defects. Using the above-mentioned wrapping process, increasing the excess glue can reduce the wrapping force and reduce the insulation void ratio. In addition, local repair filling wrapping can be performed according to the wrapping situation, which increases the flexibility of the wrapping. It is cured at room temperature, the method is simple, and various risks during the heating process are avoided. At the same time, better insulation quality can be obtained.

[0032] The above is only a preferred embodiment of the present invention, and the protection scope of the present invention is not limited to the above embodiments. All technical solutions under the concept of the present invention belong to the protection scope of the present invention. It should be pointed out that for ordinary technicians in this technical field, some improvements and modifications without departing from the principle of the present invention should also be regarded as the protection scope of the present invention.

Claims

1. A high-temperature superconducting current lead double joint box insulation wrapping process, the high-temperature superconducting current lead double joint box comprises a box body located at the end of the current lead, a U-shaped elbow is connected between the box bodies of two adjacent current leads, the box body comprises two plates arranged with a relative gap, screw holes are evenly distributed on both sides of the plate body along the height direction, the screws pass through the screw holes on the plate body to achieve the connection between the plate bodies; the ends of the screws outside the screw holes are sleeved with nuts, and a cavity for superconducting wires to pass through is formed between the two plates and the screws on both sides, characterized in that: The insulation wrapping process comprises the following steps: (1) Place a G10 insulation board on the surface of the box body facing the U-bend pipe, and use glass felt impregnated with insulating glue to pile up a climbing section towards the U-bend pipe on the G10 insulation board; (2) Place a G10 insulation board on the inner side of the cavity and fill the other gaps in the cavity with glass felt impregnated with insulating glue; (3) Fill the gaps between the screws and the screw holes with glass felt impregnated with insulating glue; (4) Place G10 insulation plates on the left, right, front and back of the box; (5) Fill the cavity with glass felt impregnated with insulating glue on the surface of the box body facing the current lead, and then place the G10 insulating board on this surface, so that the G10 insulating boards on the six surfaces of the box body form a sealed state; (6) On the G10 insulating board of the box body facing the current lead, use glass felt impregnated with insulating glue to pile up a climbing section towards the current lead; (7) Curing at room temperature.

2. The high-temperature superconducting current lead double joint box insulation winding process according to claim 1, characterized in that: In step (5), the six surfaces of the box body are fixed with the aid of polyimide tape.

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