A vacuum pressure impregnation mold assembly process and mold using the same

Abstract

The invention discloses a vacuum pressure impregnation mold assembly process and mold, the process includes: positioning the superconducting coil after installing the bottom hard mold on multiple independent support platforms; lowering the platform in sections to lay the bottom soft mold and guide components to ensure uniform gaps; installing the side soft mold and hard mold, the top guide net and the soft and hard molds in sequence, and finally welding the soft mold in sections and reinstalling the hard mold. The mold is assembled using the above method, and modular assembly is achieved by raising and lowering the independent support platform in stages. This process reduces the load on a single platform through segmented assembly, avoids precision deviation and equipment damage, and reduces the use of slings to protect the dimensional stability of the coil; the layered assembly mode of soft and hard molds is adopted to simplify the processing difficulty of large-size molds, reduce manufacturing costs and improve dimensional control accuracy; the step-by-step assembly process effectively reduces the risk of misassembly, avoids the problem of glue injection port blockage, and ensures the success rate of the vacuum pressure impregnation process.

Description

Technical Field

[0001] The invention relates to the technical field of vacuum pressure impregnation of superconducting coils, and in particular to a vacuum pressure impregnation mold assembly process and a mold using the process. Background Art

[0002] In the manufacturing process of the tokamak poloidal field coil, VPI (vacuum pressure impregnation) is an indispensable and important step. During the VPI impregnation process, the mold is required to provide an internal environment with good sealing performance and sufficient glue injection and bubbling channels, and meet the technical requirements of dimensional limitation, internal and external heating, and use under vacuum and high pressure.

[0003] However, due to the heavy weight (tens or even hundreds of tons) of the poloidal field coil, or superconducting coil, it is impossible to complete the mold assembly through multiple lifting like ordinary metal parts. If the coil is lifted multiple times to install the VPI mold, not only may the insulation of the superconducting coil be damaged, but the coil may also cause dimensional deviations during the multiple lifting processes, affecting the performance of the superconducting coil. Summary of the Invention

[0004] The purpose of the present invention is to solve the above problems and provide a vacuum pressure impregnation mold assembly process and a mold using the process.

[0005] In order to achieve the above-mentioned purpose, the present invention specifically adopts the following technical solutions:

[0006] Design a vacuum pressure impregnation mold assembly process, including:

[0007] Bottom hard mold installation: install the bottom hard molds on multiple independent support platforms;

[0008] Positioning the superconducting coil: placing the superconducting coil on the support platform, and removing the fixture after positioning is completed;

[0009] The bottom soft mold and the guide component are installed by lowering each support platform in turn, and the bottom soft mold and the guide component are laid in the center of each bottom hard mold surface. After the inner and outer gaps are kept consistent, the support platform is reset and raised to make the guide component fit the bottom of the superconducting coil;

[0010] Side soft mold installation, installing the side soft molds in sequence along the distribution order of the support platform;

[0011] After the side soft mold is installed, the side hard mold is installed on the outside of the side soft mold;

[0012] Installing the top soft mold: after installing the guide net on the upper surface of the superconducting coil, install the top soft mold and align the upper edge of the top soft mold with the upper edge of the side soft mold;

[0013] Installing the top hard mold: installing the top hard mold on the upper surface of the top soft mold, aligning the top hard mold with the bottom hard mold, and connecting the top hard mold with the side hard mold;

[0014] Soft mold welding, preliminary welding is performed on the soft mold connection parts not covered by the hard mold, and then part of the side hard mold is removed, and the soft mold is welded for the second time. After welding is completed, the hard mold is installed again.

[0015] As a further description of the above technical solution, mold detection is also included between the installation of the top hard mold and the welding of the soft mold, including:

[0016] measuring the flatness of the mold, the parallelism between the top hard mold and the bottom hard mold, and the contour between the inner mold and the outer mold; and measuring the resistance between the mold and the superconducting coil;

[0017] The flatness of the mold is less than 1 mm, the parallelism between the top hard mold and the bottom hard mold is less than 1.2 mm, the contour deviation between the inner mold and the outer mold is less than 3 mm, and the resistance value between the mold and the superconducting coil is infinite.

[0018] As a further description of the above technical solution, the steps of installing the bottom soft mold and the guide component include:

[0019] Adjust the support platform to lower it to the lowest height, and lay the bottom soft mold in the center of the bottom hard mold in sequence, with a gap between the bottom soft mold and the edge of the bottom hard mold;

[0020] Laying insulation blocks at the edges between adjacent bottom soft molds;

[0021] Laying guide plates in sequence and in the center of the bottom soft mold, and the guide plates have the same size as the bottom soft mold;

[0022] A guide net is laid on the guide plate, and after the support platform is lifted until the guide net contacts the lower surface of the superconducting coil, the edge of the guide net is trimmed.

[0023] As a further description of the above technical solution, after the bottom soft mold is installed, a filling block is inserted into a specific position of the superconducting coil, and the specific position at least includes a double joint, an outlet head and a helium tube.

[0024] As a further description of the above technical solution, the steps of installing the side hard mold include:

[0025] A plurality of limiting columns are fixed on the support platform according to the edge shape thereof;

[0026] A side hard mold is installed on the outside of the side soft mold, and the side hard mold is fixed to the limiting column through pre-tightening bolts.

[0027] As a further description of the above technical solution, the steps of installing the top soft mold include:

[0028] Laying guide nets on the upper surface of the superconducting coil in sequence, and trimming the outline of the guide nets to make them consistent with the shape and size of the surface of the superconducting coil;

[0029] Installing the top soft mold on the upper surface of the guide net in sequence;

[0030] Laying heat insulation blocks at the flange welds between the top soft molds;

[0031] The position of the top soft mold is adjusted so that the flanges of the flange soft mold are aligned, and the side edge of the top soft mold is aligned with the upper edge of the side soft mold.

[0032] As a further description of the above technical solution, the steps of installing the top die include:

[0033] Install the top hard molds on the upper surfaces of the corresponding top soft molds in sequence;

[0034] Aligning the position of the top hard mold with the position of the bottom hard mold, and aligning the side edge of the top hard mold with the upper edge of the side hard mold;

[0035] The top hard mold and the limit column are connected by bolts.

[0036] As a further description of the above technical solution, after the superconducting coil is in place, each supporting platform is lowered in turn, and then the clamp disposed outside the superconducting coil is removed, with the number of supporting platforms lowered each time not exceeding one.

[0037] As a further description of the above technical solution, a side pressure assembly is provided on the flange of the side soft mold, and the side pressure assembly is connected to the limiting column by bolts. By tightening the bolts, the side soft mold is fixed at a specified position.

[0038] Design a vacuum pressure impregnation mold and assemble it using any of the above assembly processes.

[0039] The beneficial effects of the present invention are as follows:

[0040] 1. This invention optimizes the mold assembly process. Hoists are used only during the initial hoisting phase to transfer the superconducting coil to the support platform. Subsequent assembly is completed using platform positioning. This reduces the frequency of hoisting operations to just one, effectively preventing coil structural deformation caused by repeated hoisting and ensuring the dimensional stability of the superconducting coil.

[0041] 2. The support system of this invention utilizes a multi-unit, independently elevating platform system, implementing a step-by-step operation during the base mold assembly phase. While the current mold section is being assembled, the subsequent platform sections are lowered according to a pre-set sequence to create an operating space. This dynamic adjustment mechanism ensures that the load capacity of each platform unit remains within a safe threshold, maintaining system operational stability while preventing equipment accuracy degradation caused by overload.

[0042] 3. The present invention decomposes the overall mold into multiple unit modules, and the split processing significantly reduces the difficulty of mold manufacturing. The dimensional accuracy after overall assembly is achieved through modular precision control, while reducing material loss and process deformation during the processing of large molds.

[0043] 4. The segmented assembly of the present invention also greatly reduces the difficulty of mold assembly, reduces the risk of wrong installation or missing installation, and makes the installation position of each component easier to control, thus avoiding the situation where the injection port or glue outlet is blocked due to mold assembly errors, resulting in the failure of vacuum pressure impregnation of the coil.

[0044] 5. The multi-unit segmented assembly design of the present invention facilitates independent small-scale load experiments on each platform to verify the accuracy of the platform without the need to use an oversized load equivalent to the weight of the actual coil for experiments.

[0045] In order to more clearly illustrate the structural features and functions of the present invention, the present invention is described in detail below with reference to the accompanying drawings and specific embodiments. BRIEF DESCRIPTION OF THE DRAWINGS

[0046] Figure 1 The present invention provides a flow chart of the vacuum pressure impregnation mold assembly process. DETAILED DESCRIPTION

[0047] To make the objectives, technical solutions and advantages of the embodiments of the present invention more clear, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0048] An embodiment of the present invention provides a vacuum pressure impregnation mold assembly process, which solves the problem in the prior art that, due to the heavy weight of the superconducting coil and the high requirements for assembly accuracy of the superconducting coil, the coil must be lifted by a hoist and then assembled during the mold assembly process, which may not only cause the size of the superconducting coil to deviate during the lifting process, but may also cause the body insulation on the surface of the superconducting coil that has been completed with insulation wrapping to be damaged, requiring rework, which greatly affects the normal progress of the process.

[0049] The technical concept of the present invention is that, on the one hand, there is no need to use a hoist throughout the mold assembly process. It is only necessary to use the hoist to lift the superconducting coil to the support platform in the initial stage, thereby reducing the dimensional deviation of the superconducting coil itself. On the other hand, the support platform for placing the superconducting coil is a number of independent liftable platforms. During the mold assembly, especially during the assembly of the bottom mold, the lifting platforms can be lowered in sections and the superconducting coil is assembled in sections, so that the load of a single support platform is always within a reasonable range, avoiding the deviation or even damage of the platform lifting accuracy caused by the excessive load of a single support platform. At the same time, the segmented assembly eliminates the need to process a large-sized mold at one time, reducing the difficulty of mold processing, reducing costs, and making the mold accuracy easier to control, thereby improving the accuracy of the superconducting coil size limit. In addition, the segmented assembly also greatly reduces the difficulty of mold assembly, reduces the risk of wrong installation or missing installation, and makes the installation position of each component easier to control, avoiding the situation where the injection port or glue outlet is blocked due to mold assembly errors, resulting in the failure of the coil vacuum pressure impregnation.

[0050] The VPI mold assembly process includes: installing and verifying the bottom hard mold dimensions, transferring and positioning the superconducting coil, installing the bottom soft mold, installing the side soft molds, installing the side hard molds, installing the top soft mold, installing the top hard mold, installing the sealing flange at the outlet, assembling and verifying the mold dimensions, and finally welding the soft mold. This process is described in detail with reference to the following examples.

[0051] like Figure 1 As shown, in one embodiment, a vacuum pressure impregnation mold assembly process includes the following steps:

[0052] The bottom die is installed on multiple independent support platforms. Specifically, after adjusting the support platforms to a specified height, the bottom die is mounted on the upper surface of the support platforms. The multiple bottom die forms a mold positioned at the bottom of the superconducting coil, and the structure of the multiple bottom die forms the same annular structure as the superconducting coil. After installation, the flatness and profile of the bottom die are measured using a laser tracker. The flatness of the entire bottom die is less than 1 mm, and the profile deviation is less than 3 mm, ensuring die accuracy.

[0053] The superconducting coil is placed on the support platform, and the fixture is removed after positioning is completed. Specifically, a gantry crane is used to transfer the superconducting coil from the previous process, i.e. the stacking platform, to the support platform in the VPI process, and a positioning mechanism is used to position the coil and align the characteristic line. The positioning mechanism can limit the superconducting coil to ensure that its contour is within the error range. In the process of disassembling and assembling the fixture, the height of each support platform is lowered in turn, and at most one support platform is raised or lowered at a time to ensure that the load of a single support platform is always within a reasonable range, avoiding deviations in the lifting accuracy of the platform or even damage due to excessive load on a single support platform. After the superconducting coil is placed on the support platform, a laser tracker is used to re-measure the external dimensions, contour, and position of the superconducting coil relative to the entire bottom hard mold of the superconducting coil. If the deviation is large, the superconducting coil is lifted again and the above operation is repeated until the error meets the requirements.

[0054] The vacuum seal during the VPI process is created by welding a 2mm-thick stainless steel soft mold. After the bottom hard mold is installed, the bottom soft mold and the flow guide components are installed first. Each support platform is lowered in sequence, and the bottom soft mold and flow guide components are placed in the center of each bottom hard mold surface. After maintaining the same gap between the inside and outside, the support platform is reset and raised to fit the flow guide components to the bottom of the superconducting coil. Specifically, the support platform is adjusted to the lowest height, and then the bottom soft mold is placed on the bottom hard mold. The bottom soft mold is installed in the center, with the two edges of the stainless steel having the same gap with the inner and outer step edges of the bottom hard mold to facilitate the subsequent installation of the side soft molds.

[0055] After all the bottom soft molds are laid out in sequence, insulation blocks are laid out at the flange welds between adjacent bottom soft molds to prevent damage to the body insulation during welding. In some embodiments, the insulation blocks may be G10 blocks.

[0056] After completing the above steps, install the guide plates on the bottom soft mold in sequence. The guide plates are installed in the center, and the gaps between the two side edges of the guide plates and the inner and outer edges of the bottom soft mold are the same. At the same time, it is important to note that during the installation of the guide plates, the glue injection port should not be blocked by the guide plates.

[0057] After completing the installation of the guide plate, place the guide net along the guide plate and first cut it according to a size larger than the theoretical outline. It can be understood that the theoretical outline size here is not less than the upper surface area of ​​the guide plate. After all the guide nets have been laid, reset and lift the support platform so that the guide net fits the lower surface of the superconducting coil, and then trim the outline of the guide net to make it conform to the theoretical outline. This is not only more convenient, but also can ensure the dimensional accuracy of the guide net, which is convenient for subsequent glue injection and diversion.

[0058] It should be noted that the height to which the support platform is lifted needs to be reduced by the thickness of the bottom soft mold, guide plate and guide net. After the support platform is lifted, use tools such as a steel ruler to check the position of the bottom soft mold and guide plate to see if they are centered.

[0059] After the installation of the bottom soft mold, guide plate and guide net is completed, dense blocks are filled at the double joints, outlet heads and helium tube positions of the superconducting coil to eliminate cavities and avoid the emergence of pure glue areas after the glue injection is completed, which will affect the mechanical properties of the superconducting coil after VPI.

[0060] The side soft molds are installed sequentially along the distribution of the support platforms. Specifically, the inner and outer soft molds are installed sequentially. After the inner and outer soft molds on the same support platform are installed, the side hard molds are installed immediately. The side hard molds support and limit the side soft molds, effectively reducing deviation of the side soft molds. The inner and outer soft molds are installed gradually on all support platforms, while the outer soft mold in the superconducting coil feeder connector area is installed separately.

[0061] After installing the side hard mold, install the side hard mold on the outside of the side soft mold. Specifically, tighten the limit columns on the inner and outer edges of the support platform with connecting bolts, place the side hard mold on the outside of the side soft mold, and adjust the position to fix the inner and outer hard molds to the limit columns with pre-tightening bolts.

[0062] In addition, a side pressure assembly is installed on the flange weld of the side soft mold, and the side pressure assembly is also fixed to the limit column through bolts.

[0063] After installing the guide mesh on the upper surface of the superconducting coil, install the top soft mold and align the top edge of the top soft mold with the upper edge of the side soft mold. Specifically, the guide mesh is laid on the upper surface of the superconducting coil and cut to a size larger than the theoretical outline. After all the guide mesh is laid, the outline of the guide mesh is trimmed. This is not only more convenient, but also ensures the dimensional accuracy of the guide mesh, facilitating subsequent glue injection and guide flow.

[0064] After all the guide mesh is laid, the top soft molds are sequentially installed on the upper surface of the guide mesh. Heat insulation blocks (G10 blocks) are also placed at the flange welds between adjacent top soft molds to prevent heat damage to the insulation layer during welding. The position of the top soft molds is adjusted, and the flanges of adjacent top soft molds are aligned. The inner and outer contour edges of the top soft molds are aligned with the upper edges of the side soft molds to facilitate subsequent welding and ensure accurate welding positions.

[0065] After the top soft mold is installed, the top hard mold is installed. The top hard mold is mounted on the upper surface of the top soft mold, and the top hard mold is aligned with the bottom hard mold, so that the top hard mold is connected to the side hard mold. Specifically, the top hard mold is first installed on the corresponding top soft mold, and the top hard mold is aligned with the corresponding bottom hard mold and side hard mold for installation. The bolts used to fix the limit columns are tightened, and the bolts connecting the top hard mold and the limit columns are pre-tightened. At the same time, the bolts on the pre-tightened limit columns push the inner and outer hard molds to fix the side hard molds and provide effective support for the internal soft mold.

[0066] At the same time, sealing flanges are installed at designated positions of the top soft mold and the bottom soft mold so that the wire ends of the superconducting coils can extend from the soft mold, and sealing flanges are set at the extending positions to ensure overall sealing.

[0067] After completing the initial installation of the above mold, measure the various parameters of the mold. Before measurement, tighten the bolts between the limit column and the top hard mold axially in sequence to ensure uniform load distribution. At the same time, tighten all the bolts on the limit column radially and install the side hard mold to the top position. Similarly, it also needs to be tightened in sequence to ensure uniform load distribution. After all the installation is completed, install the upper and lower connecting blocks and use a feeler gauge to check all limit surfaces.

[0068] When measuring the mold, a laser tracker is used to measure the mold as a whole. The overall flatness of the bottom hard mold is less than 1mm, and with the bottom hard mold as the reference, the parallelism between the bottom hard mold and the top hard mold is less than 1.2mm, and the contour deviation between the soft mold and the hard mold is less than 3mm.

[0069] At the same time, use an ohmmeter to check the resistance between the mold and the superconducting coil. The resistance must be infinite to ensure that the mold and the superconducting coil are electrically isolated.

[0070] After passing the measurement, weld the soft mold. Perform the welding in a sequential, step-by-step process. Spot weld the uncovered areas of the hard mold first. After spot welding, remove any limiting posts or side hard molds that may affect the welding process before welding. After welding, reinstall the hard mold and use an ohmmeter to check the resistance between the mold and the conductor again to ensure electrical isolation between the mold and the coil.

[0071] The above description of the disclosed embodiments is intended to enable one skilled in the art to implement or use the present invention. Various modifications to these embodiments will be readily apparent to one skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention is not limited to the embodiments shown herein but is intended to conform to the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A vacuum pressure impregnation mold assembly process, characterized in that: include: Bottom hard mold installation: install the bottom hard molds on multiple independent support platforms; Positioning the superconducting coil: placing the superconducting coil on the support platform, and removing the fixture after positioning is completed; The bottom soft mold and the guide component are installed by lowering each support platform in turn, laying the bottom soft mold and the guide component in the center of each bottom hard mold surface, keeping the inner and outer gaps consistent, and then resetting and lifting the support platform to make the guide component fit the bottom of the superconducting coil. The installation steps of the bottom soft mold and the guide component include: Adjust the support platform to lower it to the lowest height, and lay the bottom soft mold in the center of the bottom hard mold in sequence, with a gap between the bottom soft mold and the edge of the bottom hard mold; Laying insulation blocks at the edges between adjacent bottom soft molds; Laying guide plates in sequence and in the center of the bottom soft mold, and the guide plates have the same size as the bottom soft mold; laying a guide net on the guide plate, and trimming the edges of the guide net after the support platform is lifted until the guide net contacts the lower surface of the superconducting coil; Side soft mold installation, installing the side soft molds in sequence along the distribution order of the support platform; After the side soft mold is installed, the side hard mold is installed on the outside of the side soft mold; Installing the top soft mold: after installing the guide net on the upper surface of the superconducting coil, install the top soft mold and align the upper edge of the top soft mold with the upper edge of the side soft mold; Installing the top hard mold: installing the top hard mold on the upper surface of the top soft mold, aligning the top hard mold with the bottom hard mold, and connecting the top hard mold with the side hard mold; Soft mold welding, preliminary welding is performed on the soft mold connection parts not covered by the hard mold, and then part of the side hard mold is removed, and the soft mold is welded for the second time. After welding is completed, the hard mold is installed again.

2. The vacuum pressure impregnation mold assembly process according to claim 1, characterized in that: After the bottom soft mold is installed, a filling block is inserted into a specific position of the superconducting coil, and the specific position at least includes a double joint, an outlet head and a helium tube.

3. The vacuum pressure impregnation mold assembly process according to claim 1, characterized in that: The steps for installing the side die include: A plurality of limiting columns are fixed on the support platform according to the edge shape thereof; A side hard mold is installed on the outside of the side soft mold, and the side hard mold is fixed to the limiting column through pre-tightening bolts.

4. The vacuum pressure impregnation mold assembly process according to claim 1, characterized in that: The steps for installing the top soft mold include: Laying guide nets on the upper surface of the superconducting coil in sequence, and trimming the outline of the guide nets to make them consistent with the shape and size of the surface of the superconducting coil; Installing the top soft mold on the upper surface of the guide net in sequence; Laying heat insulation blocks at the flange welds between the top soft molds; The position of the top soft mold is adjusted so that the flanges of the flange soft mold are aligned, and the side edge of the top soft mold is aligned with the upper edge of the side soft mold.

5. The vacuum pressure impregnation mold assembly process according to claim 3, characterized in that: The steps for installing the top die include: Install the top hard molds on the upper surfaces of the corresponding top soft molds in sequence; Aligning the position of the top hard mold with the position of the bottom hard mold, and aligning the side edge of the top hard mold with the upper edge of the side hard mold; The top hard mold and the limit column are connected by bolts.

6. The vacuum pressure impregnation mold assembly process according to claim 1, characterized in that: After the superconducting coil is in place, each supporting platform is lowered in sequence, and then the clamps arranged outside the superconducting coil are disassembled, with one supporting platform being lowered each time.

7. The vacuum pressure impregnation mold assembly process according to claim 5, characterized in that: A side pressure assembly is provided on the flange of the side soft mold, and the side pressure assembly is connected to the limiting column through bolts. The side soft mold is fixed at a specified position by tightening the bolts.

8. A vacuum pressure impregnation mold, characterized in that: The assembly is performed using the assembly process described in any one of claims 1 to 7.

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