Superconducting joint hot pressing device and hot press

Abstract

The application discloses a superconducting joint hot-pressing device, relates to the technical field of high-temperature superconducting joint preparation, and mainly comprises an upper pressing block, a lower pressing block and a heating piece, the upper pressing block is used for connecting the upper end of a hot-pressing machine body, the lower pressing block is used for connecting the lower end of the hot-pressing machine body, the upper pressing block and the lower pressing block are arranged in alignment in the up-down direction and are used for pressing superconducting tapes, and the heating piece is covered on the outer side of the upper pressing block and the lower pressing block along the circumferential direction of the upper pressing block and the lower pressing block. The application further discloses a hot-pressing machine which comprises a hot-pressing machine body and the superconducting joint hot-pressing device, the upper end of the hot-pressing machine body is a pressing mechanism which can exert pressure on the upper pressing block, and the lower end of the hot-pressing machine body is a fixing mechanism which can fix the lower pressing block. The application can realize uniform heating and improve the connecting effect of the superconducting tapes.

Description

Technical Field

[0001] This invention relates to the field of high-temperature superconducting joint preparation technology, and in particular to a superconducting joint hot pressing device and hot press. Background Technology

[0002] Ultra-high performance superconducting tapes based on rare-earth barium copper oxide (REBCO) hold promise for applications in high-field magnetic resonance imaging magnets. However, due to the finite length of a single tape, achieving low-resistance connections between superconducting tapes is crucial. Superconducting joint thermocompression devices are widely used because they can directly connect superconducting layers in a zero-resistance state. However, REBCO is a ceramic material, requiring the formation of a superconducting phase structure between the two REBCO layers during the connection process. The heating effect significantly affects whether a superconducting phase structure can be formed between the two superconducting tapes.

[0003] Currently, there is a cell hot pressing device that places the cell in a sealed space and uses the cell to heat the sealed space. Because the cell is located in a specific position in the sealed space, the temperature distribution in the sealed space is uneven. The temperature of the part near the cell will be higher than the temperature of the part far away from the cell, which affects the connection effect of the superconducting tape.

[0004] Therefore, there is an urgent need for a superconducting joint hot pressing device and hot pressing machine to solve the above-mentioned technical problems. Summary of the Invention

[0005] The purpose of this invention is to provide a superconducting joint hot pressing device and hot press to solve the problems existing in the prior art, which can heat evenly and improve the connection effect of superconducting tape.

[0006] To achieve the above objectives, the present invention provides the following solution:

[0007] This invention provides a superconducting joint hot pressing device, including an upper pressing block, a lower pressing block, and a heating element. The upper pressing block is used to connect to the upper end of the hot pressing machine body, and the lower pressing block is used to connect to the lower end of the hot pressing machine body. The upper pressing block and the lower pressing block are aligned vertically for pressing superconducting tape. The heating element covers the outer side of the upper pressing block and the lower pressing block along the circumference of the upper pressing block and the lower pressing block.

[0008] In some embodiments, the heating element is a spiral heating wire, which is sleeved on the upper pressure block and the lower pressure block.

[0009] In some embodiments, both the upper pressure block and the lower pressure block are provided with multiple heat-through holes, which are capable of allowing heat to pass through.

[0010] In some embodiments, the upper pressure block is provided with a pressure-applying protrusion, which is elongated and located at one end of the upper pressure block near the lower pressure block. The lower pressure block is provided with a pressure-receiving groove corresponding to the pressure-applying protrusion, which is also elongated and located at one end of the lower pressure block near the upper pressure block. The pressure-applying protrusion can be inserted into the corresponding pressure-receiving groove.

[0011] In some embodiments, the opening direction of the heat-venting hole is consistent with the length direction of the pressure-applying boss and the pressure-receiving groove, and the heat-venting hole on the upper pressure block is not located directly above the pressure-applying boss, and the heat-venting hole on the lower pressure block is not located directly below the pressure-receiving groove.

[0012] In some embodiments, the top of the upper pressure block is provided with an upper groove for engaging the upper end of the hot press body, and the bottom of the lower pressure block is provided with a lower groove for engaging the lower end of the hot press body.

[0013] In some embodiments, the width of the pressure groove is 0.04-0.06 mm greater than the width of the pressure-applying boss.

[0014] In some embodiments, both the upper and lower pressure blocks are made of high-temperature resistant materials.

[0015] In some embodiments, a temperature measuring hole is also included, which is disposed on the upper pressure block and has a thermocouple disposed inside.

[0016] The present invention also provides a hot press, including a hot press body and a superconducting joint hot press device as described above. The upper end of the hot press body is a pressure applying mechanism that can apply pressure to the upper pressure block, and the lower end of the hot press body is a fixing mechanism that can fix the lower pressure block.

[0017] The present invention achieves the following technical effects compared to the prior art:

[0018] The superconducting joint hot pressing device provided by this invention has an upper pressing block connected to the upper end of the hot press body, and a lower pressing block connected to the lower end of the hot press body. The upper and lower pressing blocks are aligned vertically for pressing superconducting tape. Heating elements cover the outer sides of the upper and lower pressing blocks circumferentially, ensuring uniform circumferential heating of the superconducting tape during pressing. All parts of the superconducting tape can simultaneously reach the required hot pressing temperature, avoiding localized overheating or undercooling, thus improving the hot pressing quality and performance of the superconducting tape. Furthermore, the entire superconducting joint hot pressing device can be placed inside the sealed chamber of the hot press body and oxygen can be introduced, preventing oxygen loss from the superconducting tape and ensuring the critical current of the superconducting joint, thereby enabling the production of high-current joints. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the superconducting joint hot pressing device provided in some embodiments of the present invention;

[0021] Figure 2 This is a split schematic diagram of the superconducting joint hot pressing device provided in some embodiments of the present invention;

[0022] Figure 3 This is a schematic diagram of the structure of the upper pressure block and the lower pressure block provided in some embodiments of the present invention;

[0023] Figure 4 This illustrates the arrangement of two strips during the preparation of a silver diffusion connector in some embodiments of the present invention.

[0024] Figure 5 This is an example of the arrangement of two strips during the preparation of a superconducting connector, provided in some embodiments of the present invention.

[0025] In the figure: 1-Upper end of the hot press body; 2-Upper pressure block; 201-Upper groove; 202-Heating hole; 203-Pressure protrusion; 204-Temperature measuring hole; 3-Lower pressure block; 303-Pressure groove; 4-Lower end of the hot press body; 5-Spiral heating wire; 6-Silver layer; 7-Superconducting layer. Detailed Implementation

[0026] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0027] The purpose of this invention is to provide a superconducting joint hot pressing device and hot press to solve the problems existing in the prior art, which can heat evenly and improve the connection effect of superconducting tape.

[0028] To make the above-mentioned objects, features and advantages of the present invention more apparent and understandable, the present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments.

[0029] Example 1

[0030] like Figures 1-5 As shown, this invention provides a superconducting joint hot pressing device, including an upper pressing block 2, a lower pressing block 3, and a heating element. The upper pressing block 2 is used to connect to the upper end 1 of the hot pressing machine body, and the lower pressing block 3 is used to connect to the lower end 4 of the hot pressing machine body. The upper pressing block 2 and the lower pressing block 3 are vertically aligned and used to press superconducting tape. The heating element covers the outer side of the upper pressing block 2 and the lower pressing block 3 along their circumference. All parts of the superconducting tape can simultaneously reach the required hot pressing temperature, avoiding local overheating or undercooling, which helps to improve the hot pressing quality of the superconducting tape and enhance its performance. Moreover, the entire superconducting joint hot pressing device can be placed inside the sealed chamber of the hot pressing machine body and oxygen can be introduced, which can prevent the loss of oxygen from the superconducting tape, ensuring the critical current of the superconducting joint, and thus producing high-current joints.

[0031] In some embodiments, the heating element is a spiral heating wire 5, which is sleeved on the upper pressure block 2 and the lower pressure block 3. The spiral-shaped heating wire, sleeved on the upper pressure block 2 and the lower pressure block 3, can cover a large area of ​​the pressure block surface. During the heating process, heat can be distributed relatively evenly to various parts of the pressure block, and thus more evenly transferred to the superconducting tape, reducing uneven heating of the superconducting tape, ensuring temperature consistency during the pressing process, and helping to improve the pressing quality and performance stability of the superconducting tape. The two ends of the spiral heating wire 5 are connected to AC electrodes. The resistance distribution of the spiral heating wire 5 is relatively uniform. By adjusting the current, the heating temperature can be controlled relatively flexibly, enabling the hot press to adapt to the hot pressing requirements of different types of superconducting tapes. For superconducting tapes of different materials and specifications, the appropriate hot pressing temperature can be precisely adjusted, improving the versatility and adaptability of the equipment.

[0032] It should be noted that the heating element can also be a heating device with other structures, such as multiple rings arranged from top to bottom, circumferentially assembled strip heating wires, or heating films.

[0033] In some embodiments, both the upper pressure block 2 and the lower pressure block 3 are provided with multiple heat-permeable holes 202, which allow heat to pass through. The presence of the heat-permeable holes 202 increases the heat transfer channels, allowing the heat generated by the heating element (such as the spiral heating wire 5) to be transferred more quickly to the interior of the pressure block through the heat-permeable holes 202, and then more rapidly conducted to the superconducting tape, effectively shortening the heating time during the hot pressing process and improving the hot pressing efficiency. Furthermore, the multiple heat-permeable holes 202 distributed on the upper pressure block 2 and the lower pressure block 3 can form a more uniform heat flow distribution inside the pressure block, helping to avoid localized excessively high or low temperatures, ensuring that all parts of the superconducting tape are heated evenly during the pressing process, thereby guaranteeing the pressing quality of the superconducting tape and improving its performance consistency and stability. Another potential advantage of the heat-permeable holes 202 is that, during the hot pressing process, the temperature of the pressure block can be more precisely adjusted by controlling the power of the heating element. Because heat can be transferred and dissipated in a timely manner through the heat vent 202, it can respond to temperature regulation commands more quickly, achieve precise control of hot pressing temperature, and meet the strict requirements of different superconducting tapes for hot pressing temperature.

[0034] It should be noted that the heating temperature and pressure for preparing silver diffusion joints are generally selected as 450℃ and 20 MPa, with a hot-pressing time of 20 minutes; the heating temperature and pressure for preparing superconducting joints are generally selected as 810℃ and 20 MPa, with a hot-pressing time of 20 minutes. The joints that can be prepared are mainly of two types: silver diffusion joints and superconducting joints. The silver diffusion joint is prepared by aligning the uppermost silver layers 6 of the two superconducting layers 7 of the strips face to face, i.e., the silver layers 6 are tightly attached. The silver layers 6 are melted and welded together under high temperature and pressure, thus preparing a silver diffusion welded joint. See [link to documentation]. Figure 4 The superconducting connector requires first etching the silver layer 6 on the surface of the strip to expose the superconducting layer 7, and then welding the superconducting layers 7 face to face. See [link to documentation]. Figure 5 .

[0035] In some embodiments, the upper pressure block 2 is provided with a pressure-applying boss 203, which is strip-shaped and located in the middle of the end of the upper pressure block 2 away from the upper end of the hot press body. The lower pressure block 3 is provided with a pressure-receiving groove 303 corresponding to the pressure-applying boss 203, which is strip-shaped and located in the middle of the end of the lower pressure block 3 away from the lower end of the hot press body. The pressure-applying boss 203 is elongated, and the pressure-receiving groove 303 is also elongated. The pressure-applying boss 203 and the pressure-receiving groove 303 are correspondingly arranged, and the pressure-applying boss 203 can be inserted into the corresponding pressure-receiving groove 303. The corresponding arrangement of the pressure-applying boss 203 and the pressure-receiving groove 303 provides precise positioning guidance for the upper pressure block 2 and the lower pressure block 3 during the pressing process. When the hot press is working, the pressure boss 203 can accurately fall into the pressure groove 303, ensuring that the upper pressure block 2 and the lower pressure block 3 are precisely aligned when pressing the superconducting strip, avoiding offset or misalignment, thereby ensuring that the superconducting strip is subjected to uniform force during the pressing process and improving the pressing quality.

[0036] In some embodiments, the width of the pressure groove 303 is 0.04-0.06 mm wider than the width of the pressure boss 203, preferably 0.05 mm. The 0.05 mm width difference provides a certain margin of error. During the operation of the hot press, even if there is a slight positional deviation between the upper pressure block 2 and the lower pressure block 3 when they are docked, the pressure boss 203 can fall into the pressure groove 303 relatively easily, reducing the risk of pressing failure due to positioning deviation.

[0037] It should be noted that the width of the pressure boss 203 is available in various sizes, such as 4mm, 6mm, 8mm, and 12mm, and needs to be determined according to the width of the superconducting tape.

[0038] In some embodiments, the opening direction of the heat-conducting hole 202 is consistent with the length direction of the pressure-applying boss 203 and the pressure-receiving groove 303, and the heat-conducting hole 202 on the upper pressure block 2 is not located directly above the pressure-applying boss 203, and the heat-conducting hole 202 on the lower pressure block 3 is not located directly below the pressure-receiving groove 303. The heat-conducting hole 202 is positioned along the length direction of the pressure-applying boss 203 and the pressure-receiving groove 303, avoiding both locations, to ensure the mechanical strength of the heat-conducting hole 202 and prevent damage. If it were positioned perpendicular to the pressure-applying boss 203 and the pressure-receiving groove 303 during the pressing process, the heat-conducting hole 202 might be deformed by pressure directly above the pressure-applying boss 203. Similarly, if it were not positioned to avoid the pressure-applying boss 203 and the pressure-receiving groove 303, the heat-conducting hole 202 might also be deformed by pressure. Simultaneously, the opening direction of the heat-conducting hole 202 is consistent with the length direction of the pressure-applying boss 203 and the pressure-receiving groove 303, allowing heat to be directionally transferred along the critical parts of the pressing process. During hot pressing, heat can be better concentrated in the area where the superconducting wire needs to be pressed, improving the heating efficiency and temperature uniformity of the area. This helps the superconducting wire to fuse and form better during pressing, thus improving the pressing quality.

[0039] In a preferred embodiment, both the upper pressure block 2 and the lower pressure block 3 are provided with four heat-conducting holes 202, and two are provided on each side of the pressure-applying boss 203. The two heat-conducting holes 202 located on the same side are arranged vertically to provide good thermal conductivity.

[0040] In some embodiments, the upper pressure block 2 has an upper groove 201 at its top, which is used to engage with the upper end 1 of the hot press body. The lower pressure block 3 has a lower groove at its bottom, which is used to engage with the lower end 4 of the hot press body. The upper and lower grooves provide precise positioning for the connection between the upper pressure block 2, the lower pressure block 3, and the hot press body. During installation, the upper pressure block 2 and the lower pressure block 3 can accurately align with the corresponding parts of the hot press body through the grooves, ensuring the accurate position of the pressure blocks in the equipment and avoiding inaccurate pressing due to installation deviations. The engaging method makes the connection between the upper pressure block 2, the lower pressure block 3, and the hot press body tighter. The cooperation between the grooves and the hot press body can effectively transmit pressure and power. During the hot pressing process, even under large pressure and vibration, the pressure blocks are not easy to loosen, fall off, or shift, ensuring the stability of the hot press during long-term operation.

[0041] In some embodiments, both the upper pressure block 2 and the lower pressure block 3 are made of high-temperature resistant materials, such as stainless steel and graphite, which ensures stable operation even in high-temperature environments. High-temperature resistant materials have excellent anti-aging properties, effectively delaying the aging process caused by high temperatures, extending the service life of the upper pressure block 2 and the lower pressure block 3, and reducing equipment maintenance and replacement costs.

[0042] In some embodiments, the superconducting joint hot pressing device further includes a temperature measuring hole 204, which is disposed on the upper pressure block 2. A thermocouple is disposed inside the temperature measuring hole 204, capable of measuring the heating temperature and feeding it back to the computer control terminal. The thermocouple, directly disposed within the temperature measuring hole 204 of the upper pressure block 2, can measure the heating temperature during the hot pressing process in real time and accurately, and feed the measured temperature back to the computer control terminal. The computer control terminal can compare and analyze the actual measured temperature with preset hot pressing temperature parameters, and then automatically adjust the heating power or other relevant parameters to ensure that the temperature during the hot pressing process remains stable near the set value.

[0043] Example 2

[0044] This invention also provides a hot press, including a hot press body and a superconducting joint hot pressing device as described in Embodiment 1. This device can heat uniformly, improve the connection effect of superconducting strips, and can prepare silver diffusion welded joints, superconducting joints, etc. The upper end 1 of the hot press body is a pressure applying mechanism that can apply pressure to the upper pressure block 2, and the lower end 4 of the hot press body is a fixing mechanism that can fix the lower pressure block 3. The fixing mechanism at the lower end can firmly fix the lower pressure block 3, cooperating with the pressure applying mechanism at the upper end to form a stable pressing structure. During the hot pressing process, no matter how much pressure is applied by the pressure applying mechanism, the lower pressure block 3 remains fixed, ensuring the accurate relative position between the upper pressure block 2 and the lower pressure block 3.

[0045] Specific examples have been used to illustrate the principles and implementation methods of this invention. The descriptions of the above embodiments are only for the purpose of helping to understand the method and core ideas of this invention. Furthermore, those skilled in the art will recognize that, based on the ideas of this invention, there will be changes in the specific implementation methods and application scope. Therefore, the content of this specification should not be construed as a limitation of this invention.

Claims

1. A hot-pressing apparatus for superconducting joints, characterized by: The upper pressing block is used for connecting the upper end of the hot press body, the lower pressing block is used for connecting the lower end of the hot press body, the upper pressing block and the lower pressing block are arranged in alignment, and the heating element is arranged on the outer side of the upper pressing block and the lower pressing block along the circumferential direction of the upper pressing block and the lower pressing block.

2. The hot-press apparatus for superconducting joints according to claim 1, characterized by: The heating element is a spiral heating wire, and the spiral heating wire is sleeved on the upper pressing block and the lower pressing block.

3. The hot-press apparatus for superconducting joints according to claim 1, characterized by: The pressing convex is arranged on one end of the upper pressing block close to the lower pressing block, the pressing groove is arranged on one end of the lower pressing block close to the upper pressing block, and the pressing convex can be inserted into the corresponding pressing groove.

4. The hot-press apparatus for superconducting joints according to claim 3, characterized by: The width of the pressing groove is 0.04-0.06mm larger than the width of the pressing convex.

5. The hot-press apparatus for superconducting joints according to claim 3, characterized by: The through-heat holes on the upper pressing block are not located directly above the pressing convex, and the through-heat holes on the lower pressing block are not located directly below the pressing groove.

6. The superconducting joint hot press apparatus of claim 1, wherein: The top of the upper pressing block is provided with an upper groove for clamping the upper end of the hot press body, and the bottom of the lower pressing block is provided with a lower groove for clamping the lower end of the hot press body.

7. The superconducting joint hot press apparatus of claim 1, wherein: The upper pressing block and the lower pressing block are made of high-temperature-resistant materials.

8. The superconducting joint hot press apparatus of claim 1, wherein: A temperature measuring hole is arranged on the upper pressing block, and a thermocouple is arranged in the temperature measuring hole.

9. A hot press characterized by: The upper pressing block is used for connecting the upper end of the hot press body, the lower pressing block is used for connecting the lower end of the hot press body, the upper pressing block and the lower pressing block are arranged in alignment, and the heating element is arranged on the outer side of the upper pressing block and the lower pressing block along the circumferential direction of the upper pressing block and the lower pressing block.

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