High-temperature superconducting current lead insulation wrapping process

Abstract

The application discloses a high-temperature superconducting current lead insulation wrapping process, which comprises the steps of wrapping an insulation component, a superconducting component and a helium pipe by using a polyimide tape with adhesive and a wet wrapping glass tape. The application can directly adopt an on-site adhesive wrapping mode during wrapping, and cooperates with a normal-temperature curing process, so that a very high adhesive content, a relatively low insulation void ratio and a curing quality can be ensured, and the occurrence of local adhesive deficiency and uneven profile can be avoided.

Description

Technical Field

[0001] The present invention relates to the technical field of high-temperature superconductivity, and in particular to a high-temperature superconducting current lead insulation wrapping process. Background Art

[0002] High-temperature superconducting current leads are one of the core components of the superconducting magnet feeder system of nuclear fusion devices. Figure 1 As shown, the high-temperature superconducting current lead includes an insulating component 1 and a superconducting component 2. During manufacturing, the insulating component 1 and the superconducting component 2 need to be insulated and wrapped. The current insulation wrapping scheme uses pre-impregnated tape wrapping followed by heating and curing. Its shortcomings are: ① Due to the limited amount of adhesive in the pre-impregnated tape, a large operating space is required, and the wrapping force must be maintained at a high level to ensure a low insulation void ratio; ② Since the shape of the current lead generally contains a large number of copper components, the components have a large thermal inertia during heating and curing, making temperature control difficult, which affects the insulation after curing; ③ During the heating process, the higher temperature greatly increases the fluidity of the insulating adhesive. Affected by external factors such as gravity, local adhesive deficiency and poor contour can occur. Summary of the Invention

[0003] The object of the present invention is to provide a high-temperature superconducting current lead insulation wrapping process which can ensure high glue richness, low insulation void ratio and curing quality, and can also avoid the occurrence of local glue deficiency and uneven contour.

[0004] A high-temperature superconducting current lead insulation wrapping process, the high-temperature superconducting current lead includes an insulating component and a superconducting component, the superconducting component includes a superconducting stack, the superconducting stack and the insulating component are adjacent and arranged in a step-like shape, and the insulating component is provided with a helium tube near the step; the insulation wrapping process includes the following steps:

[0005] (1) Use a semi-stacked method to wrap the polyimide around the superconductor at the step to form two layers;

[0006] (2) A truncated cone-shaped G10 insulating transition block is placed outside the wrapped superconducting stack. The bottom circle of the G10 insulating transition block is filled with wet-wrap glass ribbon. The G10 insulating transition block is clamped at the root of the superconducting component and leads to a potential line.

[0007] (3) Use a semi-lapping method to wrap four layers of adhesive-coated polyimide and four layers of wet-wrap glass ribbons from the inside out around the insulating components, superconducting components and helium tubes;

[0008] (4) Passing the potential wire through the wrapping layer of the superconducting component layer by layer;

[0009] (5) Curing at room temperature.

[0010] The present invention uses adhesive-coated polyimide and wet-wrap glass ribbon to wrap insulating components, superconducting components and helium tubes, so that the on-site adhesive coating and wrapping method can be directly adopted during wrapping. Combined with the room temperature curing process, it can ensure a high adhesive content, low insulation void ratio and curing quality, and also avoid the occurrence of local adhesive deficiency and uneven contour.

[0011] Other features and advantages of the present invention will be described in detail in the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. 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 any creative work.

[0013] Figure 1 This is a schematic diagram of the structure of the high-temperature superconducting current lead in this embodiment (without the G10 insulating transition block installed);

[0014] Figure 2 This is a schematic diagram of the structure of the high-temperature superconducting current lead in this embodiment (with the G10 insulating transition block installed);

[0015] Figure 3 Schematic diagram of the lead-out structure of the potential line in this embodiment;

[0016] Figure 4 Schematic diagram of the wrapping structure of four layers of adhesive-coated polyimide and four layers of wet-wrap glass ribbons in this embodiment. DETAILED DESCRIPTION

[0017] The preferred embodiments of the present invention are described in detail below with reference to 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 precise definition of the protection scope of the present invention.

[0018] See also Figure 1 This embodiment provides a high-temperature superconducting current lead insulation wrapping process, wherein the high-temperature superconducting current lead includes an insulating component 1 and a superconducting component 2. The superconducting component 2 includes a superconducting stack 21 and a superconducting filament 22. The superconducting stack 21 is adjacent to the insulating component 1 and arranged in a stepped manner. The insulating component 1 is provided with a helium tube 3 near the step. The insulation wrapping process includes the following steps:

[0019] (1) Use a semi-lapping method to wrap the polyimide around the superconducting stack 21 at the step in two layers (to protect the exposed superconducting stack and facilitate later disassembly and maintenance);

[0020] (2) Combination Figure 2 A truncated cone-shaped G10 insulating transition block 4 is placed outside the wrapped superconducting stack 21. The bottom circle of the G10 insulating transition block 4 is filled with a wet-wrapped glass ribbon or glass felt impregnated with glue (to fix the G10 transition block). The G10 insulating transition block 4 is clamped to the root a of the superconducting component 2 by a tool (not shown). Figure 1 shown), see Figure 3 , a potential line b is drawn out at its root a, and the potential lead-out point of the potential line b is wrapped with a polytetrafluoroethylene film to prevent the low-temperature curing glue from contaminating the superconducting component 2 and affecting subsequent bonding;

[0021] (3) Use the semi-lapping method to wrap four layers of adhesive polyimide c and four layers of 0.1mm thick wet-wrap glass ribbon d (such as Figure 4 The insulating component 1 is sequentially wrapped from the inside out (wet-wrapped glass ribbon d, i.e., a glass ribbon made by a wet-wrapping process in the prior art, specifically, by applying resin to the glass ribbon for insulation processing); in the sloped portion, the overlap width of each layer of adhesive-coated polyimide c and the wet-wrapped glass ribbon d is 20 mm, and the climbing length of the eight layers is 160 mm;

[0022] (4) Use a semi-lapping method to wrap four layers of adhesive polyimide c and four layers of 0.1mm thick wet-wrap glass ribbon d (such as Figure 4 (as shown) the superconducting component 2 is wrapped sequentially from the inside out except for the steps; in the sloped portion, the overlap width of each layer of adhesive-coated polyimide c and wet-wrap glass ribbon d is 20 mm, and the climbing length of the eight layers is 160 mm;

[0023] (5) Use a semi-lapping method to wrap four layers of adhesive polyimide c and four layers of 0.1mm thick wet-wrap glass ribbon d (such as Figure 4 As shown in the figure, wrap the helium tube 3 from the inside to the outside in sequence, with each layer overlapping by more than half of the layer width. After the axial laying is completed, wrap it radially and press the joints. Each layer is overlapped with the wrapped layer of the insulating component 1.

[0024] (6) If Figure 3 As shown, the potential wire a is passed through the wrapping layer of the superconducting component 2 layer by layer; specifically, the potential wire a is pressed 20 mm below the layer when passing through each layer of wrapping. In this way, after eight layers of wrapping, the potential wire a will pass through the wrapping layer for a distance of about 160 mm. After the second layer of wet-wrapped glass ribbon, a heat shrink tube e is installed to protect the lead-out root of the potential wire a. The length of the heat shrink tube is not less than 100 mm, and when wrapping, it is necessary to prevent the potential wire from sticking to the glue.

[0025] (7) Curing at room temperature.

[0026] Since the insulating components, superconducting components and helium tubes are wrapped with adhesive polyimide c and wet-wrapped glass ribbon d, the on-site adhesive coating and wrapping method can be directly adopted during manufacturing, combined with the room temperature curing process (wet wrapping), which has the following advantages: ① The on-site coating method can ensure a high amount of adhesive, so that too much wrapping force and a large wrapping space are not required, and a low insulation void ratio can also 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 adhesive becomes worse and worse, and the influence of external interference factors will become lower and lower, thereby avoiding the situation of local adhesive deficiency and uneven contour.

[0027] In addition, combined with the structural characteristics of the current lead (large changes in cross-sectional dimensions within a short distance, and a large number of tapered sections and cooling tubes), the above-mentioned process can better solve the problems of insulation density in the variable diameter area (in the background technology, when the prepreg tape is wrapped, the variable diameter area is difficult to wrap tightly, resulting in a high insulation porosity) and the problem of local glue deficiency. At the same time, it can also ensure a smooth transition in the cooling pipe area and obtain higher insulation quality.

[0028] The above description is merely a preferred embodiment of the present invention. The scope of protection of the present invention is not limited to the above embodiment. All technical solutions based on the concept of the present invention are within the scope of protection of the present invention. It should be noted that for those skilled in the art, various improvements and modifications that do not depart from the principles of the present invention should also be considered within the scope of protection of the present invention.

Claims

1. A process for insulating and wrapping a high-temperature superconducting current lead, the high-temperature superconducting current lead comprising an insulating component and a superconducting component, the superconducting component comprising a superconducting stack, the superconducting stack being adjacent to the insulating component and arranged in a stepped manner, the insulating component being provided with a helium tube adjacent to the stepped portion, characterized in that: The insulation wrapping process comprises the following steps: (1) Use a semi-stacked method to wrap the polyimide around the superconductor at the step to form two layers; (2) A truncated cone-shaped G10 insulating transition block is placed outside the wrapped superconducting stack. The bottom circle of the G10 insulating transition block is filled with wet-wrap glass ribbon. The G10 insulating transition block is clamped at the root of the superconducting component and leads to a potential line. (3) Use a semi-lapping method to wrap four layers of adhesive-coated polyimide and four layers of wet-wrap glass ribbons from the inside out around the insulating components, superconducting components and helium tubes; (4) Passing the potential wire through the wrapping layer of the superconducting component layer by layer; (5) Curing at room temperature.

2. The high-temperature superconducting current lead insulation wrapping process according to claim 1, characterized in that: In the step (2), the potential lead-out point of the potential line is wrapped with a polytetrafluoroethylene film.

3. The high-temperature superconducting current lead insulation wrapping process according to claim 1, characterized in that: In the step (4), the potential wire is pressed 20 mm below the layer when each layer is wrapped. After the second layer of wet wrapping of the glass ribbon, a heat shrink tube is installed to protect the root of the potential wire.

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