Welding device for low-resistance high-temperature superconducting current lead

Abstract

The utility model provides a welding device for a low-resistance high-temperature superconducting current lead. Comprising a vacuum chamber which is configured to be of a detachable assembly structure; the clamping unit comprises a bottom plate and a pressurizing plate; two rows of pressure sensors are fixed on the bottom plate; pressing blocks matched with the pressure sensors are fixed on two sides of the pressurizing plate; a temperature sensor is fixed on the pressurizing plate; and the heating unit is used for heating the vacuum cabin. And a protective layer is arranged between the pressure applying surface and the superconducting tape. According to the utility model, the to-be-welded piece is clamped by the clamping unit and is heated in a vacuum environment, so that the temperature and the pressure are controlled and maintained, and the performance of the superconducting current lead after welding is improved. Wherein the pressing plate is matched with the pressure sensor, so that the superconducting tape and the welding flux are uniformly stressed in the welding process, and the pressure meets the welding requirement. The pressure sensor can adjust the pressure to ensure that the pressure required by welding is reached, and the temperature sensor ensures the temperature of the welding environment.

Description

Technical Field

[0001] The utility model relates to the technical field of superconducting electrical engineering, in particular to a welding device for low-resistance and high-temperature superconducting current leads. Background Art

[0002] With the continuous progress of superconducting theory and superconducting technology, superconducting materials are constantly being discovered and used. Some low-temperature superconducting materials have been commercialized and have been widely used. In the superconducting magnet system, the high-temperature superconducting current lead is an important component. It is an important channel connecting the inside and outside of the magnet and an indispensable part of the superconducting magnet. It can significantly reduce the cost of the low-temperature refrigeration system and the operating cost of the magnet, and significantly improve the overall performance. In the high-temperature superconducting current lead, the first generation of Bi-based high-temperature superconducting tape has entered the industrialization stage and has played a considerable role in promoting the development of superconducting application technology. At present, people are working hard to explore the application of YBCO tape and push it towards low cost, high performance and large-scale application. The welding of high-temperature superconducting tape and copper segment in the high-temperature superconducting current lead is the key part of manufacturing high-temperature superconducting current lead, which can directly affect the performance and operation stability of the entire current lead. When welding the superconducting tape and the copper segment, many factors such as pressure, heating time, and insulation time will affect their performance. Therefore, a stable welding device can achieve twice the result with half the effort in welding work. At present, there are no mature large-scale application devices for connecting high-temperature superconducting tapes at home and abroad. When conducting relevant experiments, they need to be designed by ourselves. Utility Model Content

[0003] The technical problem to be solved by the utility model is that there is no welding device which is highly universal, easy to popularize, low in cost and has good welding effect.

[0004] The utility model solves the above technical problems through the following technical means:

[0005] A welding device for a low-resistance high-temperature superconducting current lead, comprising:

[0006] A vacuum chamber, wherein the vacuum chamber is configured as a detachable assembly structure;

[0007] A clamping unit, the clamping unit comprises a bottom plate and a pressure plate; two rows of pressure sensors are fixed on the bottom plate, and pressure blocks matching the pressure sensors are fixed on both sides of the pressure plate; the pressure surface of the pressure plate 4 faces the bottom plate 1, the superconducting tape and the solder are located between the pressure surface and the current lead copper bottom plate 2, and a protective layer is also placed between the pressure surface and the superconducting tape; the temperature sensor and the pressure sensor are connected to the external device through the vacuum chamber;

[0008] The heating unit heats the vacuum chamber.

[0009] Furthermore, a bolt is fixed on the pressure sensor, and a through hole for the bolt to pass through is opened on the pressure block.

[0010] Furthermore, the bottom plate is provided with an area for placing the current lead copper bottom plate; the current lead copper bottom plate is provided with grooves for placing solder and superconducting tape; and the pressure plate is provided with a pressure surface adapted to the groove.

[0011] Furthermore, there are at least four pressure sensors, which are symmetrically arranged on the bottom plate.

[0012] Furthermore, the heating unit is a resistance wire; the resistance wire is wound outside the vacuum chamber.

[0013] Furthermore, the temperature sensor is located close to the pressure surface.

[0014] Furthermore, a protective layer is placed between the pressure surface and the superconducting tape.

[0015] The utility model also provides a welding method for a low-resistance high-temperature superconducting current lead wire, which is applied to the above-mentioned welding device and comprises the following steps:

[0016] Place the current lead copper base plate on the base plate, and place the solder and superconducting tape in the groove of the current lead copper base plate as required; then, align the pressure surface of the pressing plate with the superconducting tape, pass the bolt through the through hole on the pressing block, and screw the nut on the bolt until the pressure displayed by the pressure sensor meets the requirements, and the clamping work is completed;

[0017] Place the clamped clamping unit into the vacuum chamber, then pass the signal lines of the temperature sensor and pressure sensor through the aviation plug on the vacuum chamber and connect them to external equipment, then seal the vacuum chamber; start the vacuum pump to evacuate the vacuum chamber; after reaching the set vacuum degree, start the heating unit to heat until the welding is completed. After welding is completed, inert gas is introduced into the vacuum chamber to quickly cool it down.

[0018] The advantages of the utility model are: the utility model controls and maintains the temperature and pressure by clamping the workpiece to be welded in the clamping unit and placing it in a vacuum environment for heating, thereby improving the performance of the superconducting current lead after welding. Among them, multiple pressure plates and pressure sensors are used in combination and evenly distributed to ensure that the superconducting tape and solder are evenly stressed during welding. The pressure sensor can adjust the pressure at any time to ensure that the pressure required for welding is reached, and the temperature sensor ensures the welding environment temperature.

[0019] The heating wire is used as a heating element, which is simple to prepare and easy to operate. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1This is a schematic diagram of the overall structure of the device of Example 1 of the utility model. DETAILED DESCRIPTION

[0021] In order to make the purpose, technical solution and advantages of the embodiments of the utility model clearer, the technical solution in the embodiments of the utility model will be clearly and completely described below in combination with the embodiments of the utility model. Obviously, the described embodiments are part of the embodiments of the utility model, not all of the embodiments. Based on the embodiments of the utility model, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the utility model.

[0022] Example 1

[0023] A welding device for low-resistance high-temperature superconducting current leads comprises a vacuum chamber, a clamping unit and a heating unit.

[0024] The vacuum chamber adopts a quartz glass tube, and both ends are sealed with sealing flanges. An aviation plug is installed on the sealing flange at one end for the signal lines of the pressure sensor and the temperature sensor to pass through; and an exhaust valve is fixed on the sealing flange for connecting with a vacuum pump to evacuate the vacuum chamber.

[0025] The clamping unit includes a base plate 1 and a pressure plate 4; two rows of pressure sensors 7 are fixed on the base plate 1, and pressure blocks 5 that cooperate with the pressure sensors 7 are fixed on both sides of the pressure plate 4; a temperature sensor 6 is fixed on the pressure plate 4; the temperature sensor 6 and the pressure sensor are connected to external devices through the aviation plug 10 of the vacuum chamber; the external device is generally a measuring instrument that can display temperature and pressure, which is convenient for monitoring the environmental data of welding. In this embodiment, the number of pressure sensors 7 is at least 4, and they are symmetrically arranged in pairs to meet the requirement of uniform pressure on the welding position. In this embodiment, a hole can be opened on the pressure plate 4, and the pressure block 5 passes through the hole and extends on both sides of the pressure plate 4 to cooperate with the pressure sensor 7. Figure 1 Eight pressure sensors and four pressure blocks 5 are shown in the figure to ensure uniform force during welding of the superconducting tape and solder and to ensure that the pressure meets the welding requirements.

[0026] In this embodiment, the base plate 1, the pressure plate 4, and the pressure block 5 can be made of stainless steel, which is convenient for welding or bolt fixing. In this embodiment, a bolt 3 is fixed on the pressure sensor 7, and a through hole for the bolt 3 to pass through is opened on the pressure block 5. The pressure block 5 and the pressure sensor 7 are fixed by the cooperation of the nut and the bolt 3. An area for placing the current lead copper base plate 2 is provided on the base plate 1; a groove for placing solder and superconducting tape is opened on the current lead copper base plate 2 (not shown in the figure); and the pressure plate 4 is provided with a pressure surface adapted to the groove. When in use, the bolt 3 passes through the through hole on the pressure block 5, and then the nut and the bolt 3 are tightened, so that the pressure surface can be pressed down to complete the pressurization of the welded part. In order to protect the strip, a soft protective layer 8, such as an insulating tape or a rubber layer, is also placed between the pressure surface and the strip to prevent it from being mechanically damaged during pressurization.

[0027] In this embodiment, the temperature sensor 6 is located near the pressure surface, which is convenient for testing the real temperature of the welding area. Specifically, the pressure plate 4 is made of a rectangular high-temperature resistant plate, such as a stainless steel plate. The thickness of the pressure plate 4 is adapted to the width of the groove on the current lead copper bottom plate 2. The temperature sensor 6 can be a patch type, fixed at the lower side wall of the pressure plate 4. There can be multiple temperature sensors 6, distributed at the lower edge of the side wall of the pressure plate 4, for detecting the temperature at different positions.

[0028] Since the dimensions of the strips used for high-temperature superconducting current leads are different, when the strips are pressurized, a pressurizing plate 4 of a suitable dimension may be selected according to the parameters of the strips.

[0029] In this embodiment, the heating unit adopts a resistance wire; the resistance wire is wound around the outside of the vacuum chamber, and heats the entire heating chamber after being powered on.

[0030] Example 2

[0031] Based on the welding device of Example 1, the welding method of the low-resistance high-temperature superconducting current lead is specifically as follows:

[0032] Place the current lead copper bottom plate 2 on the bottom plate 1, and place the solder and superconducting tape in the groove of the current lead copper bottom plate 2 as required; then, align the pressure surface of the pressing plate with the superconducting tape, pass the bolt 3 through the through hole on the pressing block 5, and screw the nut on the bolt 3 until the pressure displayed by the pressure sensor meets the requirements, and the clamping work is completed;

[0033] Put the clamped clamping unit into the vacuum chamber, then pass the signal lines of the temperature sensor 6 and the pressure sensor 7 through the aviation plug 10 on the vacuum chamber and connect them to the external equipment, and then seal the vacuum chamber; start the vacuum pump 13 to evacuate the vacuum chamber; after reaching the set vacuum degree, start the heating unit to heat, set the temperature and insulation time, and then start the welding of the high-temperature superconducting current lead until the welding is completed. After the welding work is completed, inert gas (helium, nitrogen and other gases) is introduced through the vent valve 9 on the sealing flange to achieve rapid cooling, and then the vacuum chamber can be opened, the clamping unit can be disassembled, and the welded parts can be removed.

[0034] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit it. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A welding device for low-resistance high-temperature superconducting current leads, characterized in that: include: A vacuum chamber, wherein the vacuum chamber is configured as a detachable assembly structure; A clamping unit, the clamping unit comprising a base plate (1) and a pressure plate (4); a pressure sensor (7) is fixed on the base plate (1), and pressure blocks (5) cooperating with the pressure sensor (7) are provided on both sides of the pressure plate (4); the pressure surface of the pressure plate (4) faces the base plate (1), the superconducting tape and solder are located between the pressure surface and the current lead copper base plate (2), and a protective layer is also placed between the pressure surface and the superconducting tape; a temperature sensor (6) is fixed on the pressure plate (4); the temperature sensor (6) and the pressure sensor (7) pass through the vacuum chamber to communicate with external equipment; The heating unit heats the vacuum chamber.

2. A welding device for low-resistance high-temperature superconducting current leads according to claim 1, characterized in that: A bolt (3) is fixed on the pressure sensor (7), and a through hole for the bolt (3) to pass through is opened on the pressure block (5).

3. The welding device for low-resistance high-temperature superconducting current lead according to claim 1, characterized in that: The bottom plate (1) is provided with an area for placing a current lead copper bottom plate (2); the current lead copper bottom plate (2) is provided with a groove for placing solder and superconducting tape; and the pressure surface of the pressure plate (4) is adapted to the groove.

4. A welding device for low-resistance high-temperature superconducting current leads according to any one of claims 1 to 3, characterized in that: There are at least four pressure sensors (7) which are symmetrically arranged on the bottom plate (1).

5. A welding device for low-resistance high-temperature superconducting current leads according to any one of claims 1 to 3, characterized in that: The heating unit is a resistance wire; the resistance wire is wound outside the vacuum chamber.

6. The welding device for low-resistance high-temperature superconducting current lead according to claim 3, characterized in that: The temperature sensor (6) is located close to the pressure surface.

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