Vacuum pressure impregnation mold assembly process and mold applying process

Abstract

The invention discloses a vacuum pressure impregnation mold assembly process and a mold. The process comprises the following steps: mounting bottom hard molds on a plurality of independent supporting platforms, and then positioning superconducting coils; descending the platform in sections to lay a bottom soft mold and a flow guide component to ensure uniform gaps; the side edge soft mold, the side edge hard mold, the top flow guide net and the soft and hard mold are sequentially installed, and finally the soft mold is subjected to segmented welding and the hard mold is reinstalled. The mold is assembled through the method, and modular assembly is achieved by lifting the independent supporting platform in stages. According to the process, the load of a single platform is reduced through sectional assembly, precision deviation and equipment damage are avoided, and meanwhile, the use of a lifting appliance is reduced to protect the dimensional stability of the coil; a soft and hard mold layered assembly mode is adopted, the machining difficulty of a large-size mold is simplified, the manufacturing cost is reduced, and the size control precision is improved; the step-by-step assembly process effectively reduces the wrong assembly risk, avoids the problem of glue injection port blockage, and ensures the success rate of the vacuum pressure impregnation process.

Description

Technical Field

[0001] The present invention relates to the technical field of superconducting coil vacuum pressure impregnation, and particularly relates to a vacuum pressure impregnation mold assembly process and a mold applying this process. Background Art

[0002] In the manufacturing and forming process of the toroidal field coils of a tokamak, VPI (Vacuum Pressure Impregnation) is an essential and important step. During the VPI impregnation process, a mold is required to provide an internal environment with good sealing performance and sufficient glue injection and overflow 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 large weight (tens of tons or even hundreds of tons) of the toroidal field coils, i.e., superconducting coils, they cannot be assembled with the mold like ordinary metal parts by multiple hoists. If the coil is hoisted multiple times to install the VPI mold, it may not only cause damage to the insulation of the superconducting coil, but also lead to dimensional deviation of the coil during multiple hoists, affecting the performance of the superconducting coil. Summary of the Invention

[0004] The purpose of the present invention is: to solve the above problems, the present invention provides a vacuum pressure impregnation mold assembly process and a mold applying this process.

[0005] The present invention specifically adopts the following technical solutions to achieve the above purpose: Design a vacuum pressure impregnation mold assembly process, including: Installation of the bottom hard mold: install the bottom hard mold on multiple independent support platforms respectively; Placement of the superconducting coil: place the superconducting coil on the support platform, and remove the fixture after positioning; Installation of the bottom soft mold and the flow guiding component: lower each support platform in sequence, lay the bottom soft mold and the flow guiding component in the center of the surface of each bottom hard mold, and after keeping the inner and outer side clearances consistent, the support platform is reset and lifted to make the flow guiding component fit against the bottom of the superconducting coil; Installation of the side soft mold: install the side soft mold in sequence along the distribution order of the support platforms; Installation of the side hard mold: after installing the side soft mold, install the side hard mold corresponding to the outside of the side soft mold; Installation of the top soft mold: after installing a flow guiding 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 side soft mold; Installation of the top hard mold: install the top hard mold on the upper surface of the top soft mold, align the position of the top hard mold with the bottom hard mold, and connect the top hard mold with the side hard mold; Soft mold welding: initially weld the soft mold connection parts not covered by the hard mold, then remove part of the side hard mold, perform secondary welding on the soft mold, and reinstall the hard mold after welding is completed.

[0006] As a further description of the above technical solution, mold inspection is also included between the installation of the top hard mold and the soft mold welding, including: Measure the flatness of the mold, the parallelism between the top hard mold and the bottom hard mold, and the profile between the inner mold and the outer mold; and measure the resistance between the mold and the superconducting coil. Among them, 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, and the profile deviation between the inner mold and the outer mold is less than 3 mm; the resistance value between the mold and the superconducting coil is infinite.

[0007] As a further description of the above technical solution, the steps for installing the bottom soft mold and the flow guiding components include: Adjust the support platform to lower it to the lowest height, lay the bottom soft mold in the center of the bottom hard mold in sequence, and there is a gap at the edge between the bottom soft mold and the side of the bottom hard mold. Lay heat insulation blocks at the edges between adjacent bottom soft molds. Lay the flow guiding plates in the center of the bottom soft mold in sequence, and the size of the flow guiding plate is the same as that of the bottom soft mold. Lay the flow guiding net on the flow guiding plate. After the support platform is lifted until the flow guiding net contacts the lower surface of the superconducting coil, trim the edge of the flow guiding net.

[0008] As a further description of the above technical solution, after the installation of the bottom soft mold is completed, stuffing blocks are inserted into specific positions of the superconducting coil, and the specific positions at least include double joints, outgoing wire heads, and helium pipes.

[0009] As a further description of the above technical solution, the steps for installing the side hard mold include: A plurality of limit posts are fixed on the support platform according to its edge shape. Install the side hard mold outside the side soft mold and fix the side hard mold to the limit posts through pre-tightening bolts.

[0010] As a further description of the above technical solution, the steps for installing the top soft mold include: Lay the flow guiding net on the upper surface of the superconducting coil in sequence, and trim the contour of the flow guiding net to be consistent with the surface shape and size of the superconducting coil. Install the top soft mold on the upper surface of the flow guiding net in sequence. Lay heat insulation blocks at the flanging welds between the top soft molds. Adjust the position of the top soft die to align the flanging of the flanging soft die, and align the side edge of the top soft die with the upper edge of the side soft die.

[0011] As a further description of the above technical solution, the steps of installing the top hard die include: Install the top hard die on the upper surface of the corresponding top soft die in sequence; Align the position of the top hard die with the position of the bottom hard die, and align the side edge of the top hard die with the upper edge position of the side hard die; Connect the top hard die and the limit post by bolts.

[0012] As a further description of the above technical solution, after the superconducting coil is in place, after sequentially lowering each support platform, remove the fixture arranged outside the superconducting coil, and the number of the support platforms lowered each time does not exceed one.

[0013] As a further description of the above technical solution, install a side pressing component on the flanging of the side soft die, connect the side pressing component and the limit post by bolts, and tighten the bolts to fix the side soft die at a specified position.

[0014] Design a vacuum pressure impregnation mold and assemble it using the assembly process of any one of the above.

[0015] The beneficial effects of the present invention are as follows: 1. The present invention optimizes the mold assembly process. The hoisting tool is only used to transfer the superconducting coil to the support platform in the initial hoisting stage, and the subsequent assembly is completed through platform positioning throughout the process. The hoisting operation frequency is reduced to once, effectively avoiding the deformation of the coil structure caused by repeated hoisting and ensuring the dimensional stability of the superconducting coil.

[0016] 2. The support system of the present invention adopts a multi-unit independent lifting platform group and implements step-by-step operations in the bottom die assembly stage. When assembling the current section of the mold, the subsequent section of the platform descends according to a preset program to form an operation space. This dynamic adjustment mechanism ensures that the load borne by each platform unit is always within the safety threshold, maintaining both the operation stability of the system and avoiding the decline of equipment accuracy caused by overload.

[0017] 3. The present invention decomposes the overall mold into multiple unit modules. The split processing significantly reduces the mold manufacturing difficulty. 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.

[0018] 4. The segmented assembly of the present invention also greatly reduces the difficulty of mold assembly, reduces risks such as misassembly and missing assembly, makes it easier to control the installation positions of various components, and avoids the blockage of the injection port or the bleeding port caused by incorrect mold assembly, resulting in the failure of the coil vacuum pressure impregnation.

[0019] 5. The segmented assembly design of multiple units of the present invention facilitates independent small-load experiments on each platform to verify the accuracy of the platform, without the need to conduct experiments using ultra-large loads equivalent to the actual weight of the coil.

[0020] To more clearly elaborate the structural features and functions of the present invention, the present invention will be described in detail below in conjunction with the accompanying drawings and specific embodiments. Description of the Drawings

[0021] Figure 1 It is a flowchart of the vacuum pressure impregnation mold assembly process provided by the present invention. Detailed Embodiments To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions in the embodiments of the present invention will be clearly and completely described below in conjunction with the accompanying drawings in the embodiments of the present invention.

[0022] The embodiments of the present invention provide a vacuum pressure impregnation mold assembly process, which solves the problems in the prior art that due to the large weight of the superconducting coil and the high requirement for assembly accuracy of the superconducting coil, during the mold assembly process, lifting the coil with a lifting tool and then assembling it becomes a limitation. This may not only cause deviations in the size of the superconducting coil during lifting, but also may cause damage to the body insulation on the surface of the superconducting coil that has already completed insulation wrapping, resulting in the need for rework, which greatly affects the normal progress of the process.

[0023] The technical concept of the present invention lies in that, on the one hand, there is no need to use a lifting tool throughout the process of mold assembly. Only in the initial stage, the superconducting coil needs to be lifted to the support platform by the lifting tool, thereby reducing the dimensional deviation of the superconducting coil itself. On the other hand, the support platform for placing the superconducting coil is composed of several independent liftable platforms. During the mold assembly, especially during the assembly of the bottom mold, the liftable platforms can be lowered successively in sections, and then the superconducting coil can be assembled with the segmented molds. In this way, the load of a single support platform is always within a reasonable range, avoiding the situation where the lifting accuracy of the platform is deviated or even damaged due to the excessive load of a single support platform. At the same time, the segmented assembly enables the processing of large-size molds without the need for one-time processing, reducing the difficulty of mold processing, lowering costs, and making it easier to control the accuracy of the mold, thereby improving the accuracy of the dimensional limit of the superconducting coil. Moreover, the segmented assembly also greatly reduces the difficulty of mold assembly, reduces the risks of misassembly and missing assembly, makes it easier to control the installation positions of various components, and avoids the situation where the injection port or the overflow port is blocked due to incorrect mold assembly, resulting in the failure of the coil vacuum pressure impregnation.

[0024] The process flow of the VPI mold assembly is as follows: install and check the dimensions of the bottom hard mold, transfer and position the superconducting coil, install the bottom soft mold, install the side soft mold, install the side hard mold, install the top soft mold, install the top hard mold, install the sealing flange at the wire outlet, assemble and check the mold dimensions, and finally weld the soft mold. The specific description will be carried out in combination with the following embodiments.

[0025] As Figure 1 shown, in one embodiment, a vacuum pressure impregnation mold assembly process specifically includes the following steps: Installation of the bottom hard mold: Install the bottom hard mold on multiple independent support platforms respectively. Specifically, after adjusting the support platform to a specified height, install the bottom hard mold on the upper surface of the support platform. Multiple bottom hard molds form a mold arranged at the bottom of the superconducting coil, and the structure formed by multiple bottom hard molds is an annular structure identical to that of the superconducting coil. After the installation of the bottom hard mold, use a laser tracker to measure the flatness and contour of the bottom hard mold. The flatness of the overall bottom hard mold after installation is less than 1 mm, and the contour deviation of the overall bottom hard mold is less than 3 mm to control the accuracy of the mold.

[0026] 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 outer dimensions, contour, and position of the superconducting coil relative to the entire bottom hard mold. If the deviation is large, the superconducting coil is lifted again and the above operation is repeated until the error meets the requirements.

[0027] The vacuum sealing environment in the VPI process is made by welding 2mm thick stainless steel soft molds. After the bottom hard mold is installed, the bottom soft mold and the guide components are installed first, and the supporting platforms are lowered in turn. The bottom soft mold and the guide components are laid in the center of each bottom hard mold surface. After the inner and outer gaps are kept consistent, the supporting platform is reset and raised to make the guide components fit the bottom of the superconducting coil. Specifically, the supporting platform is adjusted to lower the supporting platform to the lowest height, and then the bottom soft mold is laid on the bottom hard mold. The bottom soft mold is installed in the center, and the two edges of the stainless steel have the same gap with the inner and outer step edges of the bottom hard mold, so as to facilitate the subsequent installation of the side soft mold.

[0028] After all the bottom soft molds are laid out in sequence, heat insulation blocks are laid out at the flanged welds between adjacent bottom soft molds to prevent damage to the body insulation during welding. In some embodiments, the heat insulation blocks may be G10 blocks.

[0029] 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 should be noted that during the installation of the guide plates, the glue injection port should not be blocked by the guide plates.

[0030] 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 the lifting 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.

[0031] It should be noted that the height of the support platform to be lifted needs to subtract the thicknesses of the bottom soft mold, the flow guide plate, and the flow guide net. After the lifting of the support platform is completed, use tools such as a steel ruler to recheck the positions of the bottom soft mold and the flow guide plate to see if they are centered.

[0032] After the installation of the bottom soft mold, the flow guide plate, and the flow guide net is completed, fill dense blocks at the positions of the double joints, the outgoing wire heads, and the helium pipes of the superconducting coil to eliminate cavities and avoid the appearance of a pure glue area after the glue injection, which may affect the mechanical properties of the superconducting coil after VPI.

[0033] Install the side soft molds. Install the side soft molds in sequence along the distribution order of the support platform. Specifically, install the inner and outer side soft molds in sequence. Immediately after the installation of the inner and outer side soft molds on the same support platform, install the side hard molds. By using the side hard molds to support and limit the side soft molds, the deviation of the side soft molds can be effectively reduced. Gradually complete the installation of the inner and outer side soft molds above all the support platforms, and handle the installation of the outer side soft molds in the area of the superconducting coil's feed joint separately.

[0034] Install the side hard molds. After the installation of the side soft molds, install the side hard molds corresponding to the outside of the side soft molds. Specifically, tighten and fix the limit posts at the inner and outer edges of the support platform through connecting bolts. Place the side hard molds outside the side soft molds and adjust the positions to fix the inner and outer side hard molds on the limit posts through pre-tightening bolts.

[0035] Moreover, install the side pressure components on the flanging welds of the side soft molds. The side pressure components are also fixed to the limit posts through bolts.

[0036] Install the top soft mold. After installing the flow 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 molds. Specifically, lay the flow guide net on the upper surface of the superconducting coil, and also cut it according to a size larger than the theoretical contour. After all the flow guide nets are laid, trim the contour of the flow guide net, which is not only more convenient but also can ensure the dimensional accuracy of the flow guide net, facilitating subsequent glue injection and guiding.

[0037] After all the flow guide nets are laid, install the top soft molds on the upper surface of the flow guide nets in sequence. And heat insulation blocks, namely G10 blocks, are also laid at the flanging welds between adjacent top soft molds to prevent heat damage to the insulation layer of the heat damaged body during welding. Adjust the positions of the top soft molds, align the flanges of adjacent top soft molds, and align the inner and outer contour edges of the top soft molds with the upper edge of the side soft molds to facilitate subsequent welding and the accuracy of the welding positions.

[0038] After the installation of the top soft mold is completed, install the top hard mold. Mount the top hard mold on the upper surface of the top soft mold, align the position of the top hard mold with the bottom hard mold, and connect the top hard mold with the side hard molds. Specifically, first install the top hard mold on the corresponding top soft mold, align the top hard mold with the corresponding bottom hard mold and side hard molds for installation, and tighten the bolts for fixing the limit posts. Pre-tighten the bolts connecting the top hard mold and the limit posts, and at the same time pre-tighten the bolts on the limit posts to push the inner and outer hard molds to fix the side hard molds and effectively support the inner soft mold.

[0039] Meanwhile, at the designated positions of the top soft mold and the bottom soft mold, install the sealing flanges at the wire outlet, so that the wire outlet of the superconducting coil can extend out of the soft mold, and set the sealing flanges at the extending positions to ensure the overall sealing performance.

[0040] After the preliminary installation of the above molds, measure the various parameters of the molds. Before measurement, axially tighten the bolts between the limit posts and the top hard mold in sequence to ensure uniform load distribution. At the same time, radially tighten all the bolts on the limit posts, install the side hard molds to the top position, and also tighten them in sequence to ensure uniform load distribution. After all installations are completed, install the upper and lower connection blocks, and use a feeler gauge to check all the limiting surfaces.

[0041] When measuring the molds, use a laser tracker to measure the whole molds. The overall flatness of the bottom hard mold is less than 1 mm, and based on the bottom hard mold, the parallelism between the bottom hard mold and the top hard mold is less than 1.2 mm, and the profile deviation between the soft mold and the hard mold is less than 3 mm.

[0042] Meanwhile, use an ohmmeter to check the resistance between the molds and the superconducting coil, which needs to meet infinite resistance to ensure electrical isolation between the molds and the superconducting coil.

[0043] After the measurement is qualified, weld the soft mold. Weld step by step in sequence. During the welding process, first spot-weld the parts not blocked by the hard mold. After spot-welding is completed, remove some limit posts or side hard molds that affect the welding process for welding. After welding is completed, reinstall the hard mold, and use an ohmmeter to check the resistance between the molds and the conductor again to ensure electrical isolation between the molds and the coil.

[0044] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be apparent to those skilled in the art. The general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but rather to the broadest scope consistent with the principles and novel features disclosed herein.

Claims

1. A vacuum pressure impregnation mold assembly process, characterized in that, Including: Install the bottom hard mold on multiple independent support platforms respectively; Position the superconducting coil on the support platform, and remove the fixture after positioning; Install the bottom soft mold and the flow guiding component. Lower each support platform in sequence, lay the bottom soft mold and the flow guiding component in the center of the surface of each bottom hard mold. After keeping the inner and outer side clearances consistent, the support platform is reset and lifted to make the flow guiding component fit the bottom of the superconducting coil; Install the side soft mold in sequence along the distribution order of the support platforms; Install the side hard mold. After installing the side soft mold, install the side hard mold externally corresponding to the side soft mold; Install the top soft mold. After installing the flow guiding 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 side soft mold; Install the top hard mold on the upper surface of the top soft mold, align the position of the top hard mold with the bottom hard mold, and connect the top hard mold with the side hard mold; Weld the soft mold. Initially weld the connection parts of the soft mold not covered by the hard mold, then remove part of the side hard mold, perform secondary welding on the soft mold, and reinstall the hard mold after welding is completed.

2. The vacuum pressure impregnation die assembly process according to claim 1, wherein Between the installation of the top hard mold and the welding of the soft mold, there is also mold detection, including: Measure the flatness of the mold, the parallelism between the top hard mold and the bottom hard mold, and the contour deviation between the inner mold and the outer mold; and measure the resistance between the mold and the superconducting coil; Wherein, 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; the resistance value between the mold and the superconducting coil is infinite.

3. The vacuum pressure impregnation mold assembly process according to claim 1, characterized in that, The steps of installing the bottom soft mold and the flow guiding component include: Adjust the support platform to lower the support platform to the lowest height, lay the bottom soft mold in the center of the bottom hard mold in sequence, and there is a clearance at the edge between the bottom soft mold and the side of the bottom hard mold; Lay heat insulation blocks at the edges between adjacent bottom soft molds; Lay the flow guiding plates in the center of the bottom soft mold in sequence, and the size of the flow guiding plate is the same as that of the bottom soft mold; Lay the flow guiding net on the flow guiding plate. After the support platform is lifted until the flow guiding net contacts the lower surface of the superconducting coil, trim the edge of the flow guiding net.

4. The vacuum pressure impregnation mold assembly process according to claim 1, characterized in that, After the installation of the bottom soft mold is completed, insert filling blocks at specific positions inside the superconducting coil, and the specific positions at least include double joints, lead-out heads, and helium pipes.

5. The vacuum pressure impregnation die assembly process according to claim 1, characterized in that, The steps of installing the side hard mold include: Fix multiple limit posts on the support platform according to its edge shape; Install the side hard mold outside the side soft mold, and fix the side hard mold to the limit posts through pre-tightening bolts.

6. The vacuum pressure impregnation mold assembly process according to claim 1, characterized in that, The steps of installing the top soft mold include: Lay the flow guiding net on the upper surface of the superconducting coil in sequence, and trim the contour of the flow guiding net to be consistent with the surface shape and size of the superconducting coil; Install the top soft mold on the upper surface of the flow guiding net in sequence; Lay heat insulation blocks at the flanging welds between the top soft molds; Adjust the position of the top soft die to align the flanging of the flanging soft die, and align the side edge of the top soft die with the upper edge of the side soft die.

7. The vacuum pressure impregnation die assembly process according to claim 5, characterized in that, The steps of installing the top hard die include: Install the top hard die on the upper surface of the corresponding top soft die in sequence; Align the position of the top hard die with the position of the bottom hard die, and align the side edge position of the top hard die with the upper edge position of the side hard die; Connect the top hard die and the limit post by bolts.

8. The vacuum pressure impregnation die assembly process according to claim 1, characterized in that, After the superconducting coil is in place, lower each support platform in sequence, and then remove the fixture arranged outside the superconducting coil. The number of the support platforms lowered each time does not exceed one.

9. The vacuum pressure impregnation die assembly process according to claim 7, characterized in that, Set a side pressing component on the flanging of the side soft die. The side pressing component is connected to the limit post by bolts. By tightening the bolts, the side soft die is fixed at a specified position.

10. A vacuum pressure impregnation mold, characterized in that, Assemble using the assembly process according to any one of claims 1-9.

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