Leakage detection tool suitable for welding seam of pipeline in vacuum chamber of fusion device

Abstract

The invention relates to the technical field of nuclear fusion vacuum, and particularly discloses a leak detection tool suitable for a pipeline welding seam in a vacuum chamber of a fusion device, which comprises a pair of oppositely arranged sealing seats, cavities are formed in the sealing seats, grooves matched with a pipeline are formed in the two ends of each sealing seat, when the two sealing seats are combined, the two cavities jointly form a detection cavity, and the two corresponding grooves jointly form a limiting groove used for restraining the position of the pipeline; wherein the detection cavity is of a sealed structure, and the sealing seat is provided with an air exhaust interface used for being connected with external vacuum equipment so as to be used for vacuumizing the outside of the weld joint of the pipeline to be detected, which is sealed and restrained. Therefore, under the condition of high reduction degree, the detection steps and the detection time efficiency are optimized, and the accuracy and the reliability of the detection result are ensured.

Description

Technical Field

[0001] This invention relates to the field of nuclear fusion vacuum technology, specifically to a leak detection tool for pipe welds in the vacuum chamber of a fusion device. Background Technology

[0002] In the field of new energy development, nuclear fusion technology has become one of the important directions for future energy development due to its significant advantages such as being clean, efficient, and resource-rich. Whether future fusion devices can achieve long-term safe and stable operation is directly related to the practical application progress of nuclear fusion technology. Among these, plasma generation and maintenance are the core links in the operation of fusion devices, and this link has extremely high requirements for the vacuum chamber environment. To ensure the normal operation of the plasma, the vacuum chamber needs to maintain an ultra-high vacuum state, with a vacuum level of 10⁻⁵. -5 The Pa level is a key prerequisite for ensuring the smooth progress of fusion reactions and avoiding impurities from interfering with plasma operation.

[0003] During the assembly of internal components in the vacuum chamber of a future fusion device, the piping system within the vacuum chamber is extremely complex due to the structural and functional requirements of the device (e.g., Figure 1 As shown in the diagram, the vacuum chamber not only has a dense piping layout but also numerous joints and welds. Furthermore, the relatively small internal space further complicates piping assembly and subsequent leak detection. To ensure the vacuum chamber can stably maintain an ultra-high vacuum environment, it is crucial to guarantee that all pipe joints and welds are leak-free. Any leaks will directly compromise the vacuum level of the chamber, interfering with plasma experiments and potentially affecting the overall safe operation of the fusion device. Therefore, precise leak detection of each joint and weld is essential.

[0004] Currently, the negative pressure method is one of the more common leak detection methods in pipeline operations. However, its application to leak detection in the vacuum chamber pipelines of future fusion devices has significant drawbacks: Firstly, due to the complexity of the vacuum chamber pipelines and space limitations, the vacuum pumping process is time-consuming, making it difficult to meet the high-efficiency leak detection requirements during the research and development and operation of fusion devices. Secondly, the leak detection conditions of the negative pressure method do not match the actual operating conditions of the pipelines, failing to accurately reflect the sealing performance of the pipelines under normal operating conditions, making it difficult to ensure the reliability of the leak detection results, and thus failing to effectively guarantee the ultra-high vacuum environment of the vacuum chamber and the stable operation of the fusion device. In summary, how to efficiently and accurately perform individual leak detection on each joint and butt weld under the complex and confined space conditions of the vacuum chamber pipelines of future fusion devices has become an urgent technical challenge to be solved in the current research and development of fusion devices.

[0005] Based on the current situation, it is necessary to optimize and improve the existing leak detection devices to optimize the detection steps and detection time while maintaining high fidelity, and to ensure the accuracy and reliability of the detection results. Summary of the Invention

[0006] The purpose of this invention is to provide a leak detection fixture for pipe welds in the vacuum chamber of a fusion device, which optimizes the detection steps and detection time while maintaining high fidelity, and ensures the accuracy and reliability of the detection results.

[0007] This invention is achieved through the following technical solution: A leak detection fixture for welded pipes inside a vacuum chamber of a fusion device includes a pair of opposing sealing seats. Each sealing seat has a cavity, and both ends of the sealing seat are provided with grooves adapted to the pipe. When the two sealing seats are assembled, the two cavities together form a detection chamber, and the two corresponding grooves together form a limiting groove for constraining the position of the pipe. The detection chamber is a sealed structure, and the sealing seat is provided with an air extraction interface for connecting to an external vacuum device to evacuate the welded pipe to be sealed and constrained.

[0008] In one possible design, the limiting groove is provided with a first sealing groove for accommodating a first sealing body made of a flexible material so as to fit tightly against the pipe when compressed.

[0009] In one possible design, the longitudinal section of the first sealing groove is square, and the contact surface between the first sealing body and the square groove is an arc surface.

[0010] In one possible design, the outer side of the groove is provided with a second sealing groove for receiving a second sealing body, the second sealing body being made of a flexible material so as to fit tightly against the sealing seat when compressed.

[0011] In one possible design, the longitudinal section of the second sealing groove is square, and the contact surface between the second sealing body and the square groove is an arc surface.

[0012] In one possible design, the limiting groove is provided with a first sealing groove for accommodating a first sealing body, and the outer side of the groove is provided with a second sealing groove for accommodating a second sealing body, the first sealing groove being connected to the second sealing groove; the first sealing body and the second sealing body are integrally formed.

[0013] In one possible design, the first seal and the second seal are made of the same material, namely fluororubber.

[0014] In one possible design, the sealing seat is made of 316L stainless steel.

[0015] In one possible design, the two sealing seats are detachably connected by screws.

[0016] In one possible design, the air extraction port is sealed to the sealing seat via a detachable connection structure.

[0017] The working process of this leak detection fixture for pipe welds in the vacuum chamber of a fusion device is as follows: First, determine the location of the pipe weld to be inspected in the vacuum chamber, and clean the impurities (such as dust, oil, etc.) from the weld and the outer surface of the pipe to avoid impurities affecting the sealing fit between the fixture and the pipe; at the same time, check the sealing performance of the sealing seat (such as whether the seals at the edge of the cavity are intact), and pre-connect the external vacuum equipment (such as vacuum pumps and vacuum gauges) to the evacuation port on the sealing seat to ensure that the vacuum equipment is in normal working condition.

[0018] A pair of sealing seats are inserted into the pipe from both sides of the weld to be inspected, ensuring that the grooves at both ends of each sealing seat fit snugly against the outer wall of the pipe. The position of the sealing seats is adjusted so that the weld to be inspected is precisely located between the cavities of the two sealing seats. Then, the two sealing seats are brought together along the pipe axis. At this point, the grooves of the two sealing seats together form a limiting groove, tightly wrapping the outer wall of the pipe, achieving radial constraint on the pipe and preventing the tooling from shifting during leak detection. Simultaneously, the cavities of the two sealing seats are joined to form a detection chamber, which is sealed by a sealing structure to ensure complete isolation from the external environment, covering only the outer area of ​​the weld to be inspected.

[0019] The external vacuum equipment is activated, and a vacuum is applied to the sealed testing chamber through the evacuation port on the sealing seat. Since the testing chamber is set up around only a single weld, its volume is much smaller than the entire pipeline or large space that can be evacuated by the traditional negative pressure method. The vacuum equipment can quickly reduce the air pressure in the testing chamber to the target vacuum level, and the vacuum level change in the testing chamber can be monitored in real time by a vacuum gauge.

[0020] Because the leak detection fixture has a very small volume, and the external vacuum equipment is a helium mass spectrometer leak detector, the background leak rate of the fixture can be quickly reduced to ≤1x10⁻⁶. -10 pam 3 / s, to meet the leak detection conditions. During the leak detection test, helium gas is used to purge the outside of the fixture. If the helium leak detector reading does not change, it indicates a good seal between the fixture and the tested pipeline. If the background reading of the leak detector increases, it indicates a leak between the fixture and the tested pipeline, requiring resealing. With a good seal between the fixture and the pipeline, helium gas at a certain pressure is injected into the tested pipeline, and the leak detector reading is observed for any changes. If the leak detector reading does not change within 5 minutes, it indicates no leaks in the welds or joints of the tested pipeline, and the welds or joints are qualified. If the leak detector reading increases, it indicates a leak in the welds or joints of the tested pipeline, and the welds or joints are unqualified. When applying this method, those skilled in the art can flexibly configure the fixture's structure according to the site conditions, such as connecting multiple welds or joints at once, which can achieve simultaneous leak detection at multiple points and improve the overall leak detection efficiency. In addition, fixtures with different diameters on both sides can also be made to accommodate pipelines with unequal diameters.

[0021] After completing the leak detection of a single weld, the two sealing seats are separated along the pipe axis and removed from the pipe. After cleaning the tooling, it can be transferred to the next weld to be tested. Repeat the above steps to achieve individual leak detection of all pipe joint welds inside the vacuum chamber.

[0022] The advantages of this invention over the prior art are as follows: Through the above technical solution, based on the structural design of the leak detection fixture, the external area of ​​the weld to be detected can be wrapped by the detection cavity formed by the combination of two sealing seats. Moreover, the detection cavity is an independent sealing structure, which can prevent gas from flowing between complex pipelines during the leak detection process, and can also carry out detection for each weld individually, greatly reducing the complexity of the leak detection operation.

[0023] The grooves at both ends of the sealing seat fit the outer wall of the pipe, and the resulting limiting groove provides radial constraint on the pipe, preventing the tooling from shifting during vacuuming or operation. This ensures the weld remains in the center of the inspection chamber, avoiding missed detections due to positional deviation. Furthermore, the adaptable design of the grooves accommodates vacuum pipes of different diameters, enhancing the tooling's versatility and eliminating the need for separate leak detection tools for different pipe specifications.

[0024] Because the detection chamber adopts a sealed structure and is directly connected to external vacuum equipment through the air extraction interface, the air pressure in the detection chamber can be reduced to the same vacuum level as the operating conditions of the fusion device's vacuum chamber. This makes the leak detection environment highly consistent with the actual working environment of the pipeline, which can more realistically reflect the sealing performance of the weld when the fusion device is running, and avoid false acceptance or misjudgment due to differences in operating conditions.

[0025] Compared to the traditional negative pressure method of evacuating the entire pipeline or large space, this fixture's testing chamber is set around a single weld, making it extremely small. Vacuum equipment can quickly evacuate the testing chamber to the target vacuum level, significantly shortening the evacuation time and solving the problem of long evacuation times associated with the negative pressure method. Furthermore, its small size and modular sealing seat structure are better suited to working environments with confined vacuum chambers and dense piping. Installation and disassembly do not require extensive movement of surrounding pipelines, making operation convenient and reducing the space requirements for assembly within the vacuum chamber. Attached Figure Description

[0026] To more clearly illustrate the technical solutions of the exemplary embodiments of the present invention, the accompanying drawings used in the embodiments will be briefly described below. It should be understood that the following drawings only show some embodiments of the present invention and should not be considered as a limitation of the scope. For those skilled in the art, other related drawings can be obtained based on these drawings without creative effort. In the drawings: Figure 1 The diagram below is a schematic diagram of the vacuum chamber piping system described in the background art. The schematic diagram is a 3D screenshot, and the gray background in the attached diagram does not constitute a constraint or limitation on the solution. Figure 2 This is a three-dimensional structural diagram of the leak detection tool for pipe welds in the vacuum chamber of a fusion device provided by the present invention in one application scenario. Some of the structure has been removed to show the internal structure. Figure 3 This is a three-dimensional structural diagram of the leak detection tool for pipe welds in the vacuum chamber of a fusion device provided by the present invention in another application scenario. Some of the structure has been removed to show the internal structure. Figure 4 A schematic diagram of the structure of the leak detection fixture for pipe welds in the vacuum chamber of a fusion device provided by the present invention in one embodiment; Figure 5 A cross-sectional view of one embodiment of the leak detection fixture for pipe welds in the vacuum chamber of a fusion device provided by the present invention. Figure 6 A schematic diagram of the structure of the first and second sealing bodies in the leak detection fixture for pipe welds in the vacuum chamber of a fusion device provided by the present invention; Figure 7 This is a schematic diagram of the sealing seat in the leak detection fixture for pipe welds in the vacuum chamber of a fusion device provided by the present invention.

[0027] The attached diagram shows the markings and corresponding component names: 1-Sealing seat, 2-Cavity, 3-Groove, 4-Evacuation port, 51-First sealing groove, 52-Second sealing groove, 61-First sealing body, 62-Second sealing body, 7-Pipe. Detailed Implementation

[0028] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. It should be noted that while the description of these embodiments is intended to aid in understanding the invention, it does not constitute a limitation thereof. The specific structural and functional details disclosed herein are only for describing exemplary embodiments of the invention. However, the invention can be embodied in many alternative forms and should not be construed as being limited to the embodiments described herein.

[0029] According to specific embodiments of this disclosure, a leak detection fixture suitable for pipe welds in the vacuum chamber of a fusion device is provided. This fixture has a compact structure and small size, allowing for the testing of the sealing performance of pipe welds without any modification to the pipes. It is convenient for operation and use within a vacuum chamber and is suitable for vacuum leak detection of pipe joints and butt welds, thus having a wide range of applications. Figures 2 to 7 Specific embodiments thereof are shown.

[0030] See Figures 2 to 7 As shown, the leak detection fixture for the weld seam of the pipeline in the vacuum chamber of a fusion device includes a pair of oppositely arranged sealing seats 1; the sealing seat 1 forms a cavity 2, and both ends of the sealing seat 1 are provided with grooves 3 that are adapted to the pipeline 7. When the two sealing seats 1 are combined, the two cavities 2 together form a detection chamber, and the two corresponding grooves 3 together form a limiting groove for constraining the position of the pipeline 7; wherein, the detection chamber is formed as a sealed structure, and the sealing seat 1 is provided with a vacuum port 4 for connecting to an external vacuum device, so as to evacuate the external vacuum of the weld seam of the pipeline 7 to be sealed and constrained.

[0031] The working process of this leak detection fixture for the weld seams of the vacuum chamber pipes in a fusion device is as follows: First, determine the location of the weld seam of the vacuum pipe 7 to be inspected, and clean the impurities (such as dust, oil, etc.) on the weld seam and the outer surface of the pipe 7 to avoid impurities affecting the sealing fit between the fixture and the pipe 7; at the same time, check the sealing performance of the sealing seat 1 (such as whether the seals at the edge of the cavity 2 are intact), and pre-connect the external vacuum equipment (such as a vacuum pump or vacuum gauge) to the evacuation port 4 on the sealing seat 1 to ensure that the vacuum equipment is in normal working condition.

[0032] A pair of sealing seats 1 are inserted into the pipe 7 from both sides of the weld to be inspected, so that the grooves 3 at both ends of each sealing seat 1 fit against the outer wall of the pipe 7. The position of the sealing seats 1 is adjusted so that the weld to be inspected is exactly between the cavities 2 of the two sealing seats 1. Then, the two sealing seats 1 are brought together along the axis of the pipe 7. At this time, the grooves 3 of the two sealing seats 1 together form a limiting groove, which tightly wraps the outer wall of the pipe 7, thereby achieving radial constraint on the pipe 7 and preventing the tooling from shifting during the leak detection process. At the same time, the cavities 2 of the two sealing seats 1 are spliced ​​to form a detection chamber, and the detection chamber is sealed by a sealing structure to ensure that the detection chamber is completely isolated from the external environment and only wraps the outer area of ​​the weld to be inspected.

[0033] The external vacuum equipment is activated, and a vacuum is applied to the sealed detection chamber through the evacuation port 4 on the sealing seat 1. Since the detection chamber is set only around a single weld, its volume is much smaller than the entire pipeline or large space that can be evacuated by the traditional negative pressure method. The vacuum equipment can quickly reduce the air pressure in the detection chamber to the target vacuum level, and the vacuum level change in the detection chamber can be monitored in real time by a vacuum gauge.

[0034] Because the leak detection fixture has a very small volume, and the external vacuum equipment is a helium mass spectrometer leak detector, the background leak rate of the fixture can be quickly reduced to ≤1x10⁻⁶. -10 pam 3 / s, to meet the leak detection conditions. During the leak detection test, helium gas is used to purge the outside of the fixture. If the helium leak detector reading does not change, it indicates a good seal between the fixture and the tested pipeline. If the background reading of the leak detector increases, it indicates a leak between the fixture and the tested pipeline, requiring resealing. With a good seal between the fixture and the pipeline, helium gas at a certain pressure is injected into the tested pipeline, and the leak detector reading is observed for any changes. If the leak detector reading does not change within 5 minutes, it indicates no leaks in the welds or joints of the tested pipeline, and the welds or joints are qualified. If the leak detector reading increases, it indicates a leak in the welds or joints of the tested pipeline, and the welds or joints are unqualified. When applying this method, those skilled in the art can flexibly configure the fixture's structure according to the site conditions, such as connecting multiple welds or joints at once, which can achieve simultaneous leak detection at multiple points and improve the overall leak detection efficiency. In addition, fixtures with different diameters on both sides can also be made to accommodate pipelines with unequal diameters.

[0035] After completing the leak detection of a single weld, the two sealing seats 1 are separated along the axis of pipe 7 and removed from pipe 7. After cleaning the tooling, it can be transferred to the next weld to be tested. Repeat the above steps to achieve individual leak detection of all pipe 7 joint welds inside the vacuum chamber.

[0036] Based on the structural design of this leak detection fixture, the detection chamber formed by the combination of two sealing seats 1 can wrap the external area of ​​the weld to be detected. Moreover, the detection chamber is an independent sealing structure, which can prevent gas from flowing between complex pipelines during the leak detection process, and can also conduct individual detection on each weld, greatly reducing the complexity of the leak detection operation.

[0037] The grooves 3 at both ends of the sealing seat 1 are adapted to the outer wall of the pipe 7. The limiting groove formed after assembly can radially constrain the pipe 7, preventing the tooling from shifting during vacuuming or operation, ensuring that the weld is always in the center of the detection chamber, and avoiding missed detection due to positional deviation. At the same time, the adaptability design of the grooves 3 is compatible with vacuum pipes 7 of different diameters, improving the versatility of the tooling and eliminating the need to design separate leak detection tools for pipes 7 of different specifications.

[0038] Because the detection chamber adopts a sealed structure and is directly connected to external vacuum equipment through the air extraction interface 4, the air pressure in the detection chamber can be reduced to the same vacuum level as the operating conditions of the fusion device vacuum chamber. This makes the leak detection environment highly consistent with the actual working environment of the pipeline 7, which can more realistically reflect the sealing performance of the weld when the fusion device is running, and avoid false acceptance or misjudgment due to differences in operating conditions.

[0039] Compared to the traditional negative pressure method of evacuating the entire pipeline or a large space, the testing chamber of this fixture is set only around a single weld, making it extremely small. Vacuum equipment can quickly evacuate the testing chamber to the target vacuum level, significantly shortening the evacuation time and solving the problem of long evacuation time in the negative pressure method. In addition, the small-volume, split-type sealing seat 1 structure is more suitable for working environments with confined vacuum chambers and dense pipelines. Installation and disassembly do not require large-scale movement of surrounding pipelines, making operation convenient and reducing the requirements for internal assembly space in the vacuum chamber.

[0040] It should be noted that the directional terms used, such as "inner" and "outer," refer to "inner" and "outer" relative to the outline of the component. "Inner" refers to the direction towards the inside of the component, and "outer" refers to the direction away from it. Furthermore, it should be noted that the terms used, such as "first" and "second," are used to distinguish one element from another and do not indicate sequence or importance. Moreover, in the following descriptions with accompanying drawings, the same reference numerals in different drawings represent the same element.

[0041] In one embodiment provided in this disclosure, a first sealing groove 51 is provided in the limiting groove for accommodating a first sealing body 61. The first sealing body 61 is made of a flexible material so that it can fit tightly against the pipe 7 when squeezed.

[0042] The first sealing groove 51, located within the limiting groove, provides installation space and a mechanical fixing structure for the first sealing body 61. On one hand, it prevents the flexible sealing body from shifting during tooling installation / disassembly, ensuring that the sealing body remains in contact with the limiting groove and the outer wall of the pipe 7, thus avoiding localized sealing gaps caused by misalignment. The groove dimensions precisely match the shape of the first sealing body 61, thereby limiting the direction of excessive deformation of the sealing body and concentrating the deformation of the sealing body on the contact surface of the pipe 7.

[0043] Flexible materials (such as silicone and fluororubber) have excellent elastic deformation capabilities. When the tooling is assembled, the sealing body undergoes adaptive deformation due to the compression between the limiting groove and the outer wall of the pipe 7. This allows it to conform to the protruding parts of the outer wall of the pipe 7 and fill the tiny gaps formed by depressions or scratches, achieving a seamless seal and preventing leakage areas between the limiting groove and the pipe 7. In addition, since the flexible first sealing body 61 has soft contact with the outer wall of the pipe 7, it will not cause physical damage to the surface of the pipe 7 during compression. This ensures the structural integrity of the pipe 7 and avoids new leakage risks caused by damage to the outer wall, thus protecting the long-term stable operation of the vacuum pipe 7.

[0044] Specifically, the longitudinal section of the first sealing groove 51 is square, and the contact surface between the first sealing body 61 and the square groove is an arc surface.

[0045] The two side walls of the square first sealing groove 51 can limit the displacement of the first sealing body 61, preventing the first sealing body 61 from spreading to the non-sealing area when the tooling is assembled and squeezed, and ensuring that the deformation of the first sealing body 61 is always concentrated between the outer wall of the pipe 7 and the groove wall. When the two sealing seats 1 are assembled, the first sealing body 61 is subjected to bidirectional compression from the outer wall of the pipe 7 and the square groove wall, and its circular cross section will deform evenly in four directions: up, down, left, and right. In this way, the arc-shaped surface of the first sealing body 61 fits tightly against the outer wall of the pipe 7. Even if there are minor unevennesses in the pipe 7 (such as local protrusions or depressions), the deformation of the arc-shaped surface can adaptively wrap the protrusions and fill the depressions.

[0046] In addition, since the distance from each point of the cross section of the first sealing body 61 to the center is equal, there are no dead angles in the stress distribution during extrusion deformation, and there will be no problems of stress concentration at the edges and corners or insufficient pressure in the middle. This ensures that the reaction force is evenly distributed along the contact surface of the sealing body, further enhancing the consistency of the sealing pressure.

[0047] In one embodiment provided in this disclosure, a second sealing groove 52 for accommodating a second sealing body 62 is provided on the outer side of the groove 3. The second sealing body 62 is made of a flexible material so that it can fit tightly against the sealing seat 1 when compressed.

[0048] The second sealing body 62 on the outside of the groove 3 will be squeezed by the mating surfaces of the two sealing seats 1 when the tooling is assembled. The second sealing body 62, made of flexible material (such as vacuum-resistant fluororubber or silicone), will deform adaptively to fill the tiny gaps between the mating surfaces and even wrap the edge burrs to form a sealing surface, completely blocking the path of leakage of the detection cavity to the outside through the mating surface, and achieving all-round sealing of the detection cavity.

[0049] The second sealing groove 52 is located outside the groove 3, which can restrict the displacement of the second sealing body 62 and ensure that the second sealing body 62 always covers the sealing area of ​​the mating surface of the sealing seat 1, thereby isolating the detection chamber from the external environment and ensuring that the change in vacuum degree in the detection chamber is determined only by the weld to be detected.

[0050] Specifically, the longitudinal section of the second sealing groove 52 is square, and the contact surface between the second sealing body 62 and the square groove is an arc surface.

[0051] The function of the second sealing body 62 is to seal the mating surfaces of the two sealing seats 1 (the outer side of the groove 3 is the mating surface when the sealing seats 1 are assembled), preventing external atmosphere from seeping into the detection chamber from this mating surface. The longitudinal section structure of the square second sealing groove 52 provides a stable mechanical limiting basis for the second sealing body 62, so that the flat bottom of the square groove and the vertical sidewall form a clear boundary limiting, avoiding irregular displacement of the second sealing body 62 during extrusion deformation, and ensuring that the sealing body always fills the gap area of ​​the mating surface of the sealing seats 1.

[0052] The flexible material of the second sealing body 62 deforms under pressure, ensuring the sealing strength of the mating surface and preventing permanent deformation of the sealing body due to excessive local compression. This extends the service life of the second sealing body 62 and reduces the maintenance cost of the fusion device leak detection tool. Consequently, the sealing performance of the detection chamber is improved, enabling accurate determination of whether there is a leak at the weld of pipe 7 during subsequent leak detection, thus enhancing the effectiveness and reliability of the detection results.

[0053] In a preferred embodiment of this disclosure, the limiting groove is provided with a first sealing groove 51 for accommodating the first sealing body 61, and the outer side of the groove 3 is provided with a second sealing groove 52 for accommodating the second sealing body 62. The first sealing groove 51 is connected to the second sealing groove 52. The first sealing body 61 and the second sealing body 62 are integrally formed.

[0054] The interconnected sealing grooves form a continuous accommodating space, which can be completely filled by the integrally molded sealing body, forming a continuous sealing ring without any breaks. When the sealing seat 1 is compressed together, the pipe 7 fitting section (original first sealing body 61) of the integral sealing body and the docking section (original second sealing body 62) of the sealing seat 1 will deform synchronously. There are no gaps at the joint between the two, which completely blocks the gas from seeping in, so that the leakage rate of the detection chamber meets the requirements of the fusion device.

[0055] Furthermore, the one-piece molded sealing body can be embedded into the connected first sealing groove 51 and second sealing groove 52 in one go, eliminating the need to install two separate sealing bodies. The operator only needs to push the one-piece sealing body into the opening of the connecting groove; there is no need to repeatedly adjust the position of the sealing body in the two grooves during insertion. This allows for installation by feel even in confined spaces with obstructed visibility, avoiding sealing failure caused by misalignment of the separate sealing bodies. Consequently, the sealing space on the mating side of the pipe 7 and the mating side of the sealing seat 1 is filled simultaneously, reducing assembly steps and shortening tooling assembly and disassembly time.

[0056] Even during long-term vacuuming, the elastic deformation of the integrated seal can always maintain a tight fit with the sealing groove, pipe 7, and sealing seat 1, avoiding slow leakage caused by aging of the seal, ensuring stable vacuum in the detection chamber during leak detection, and improving the accuracy and repeatability of leak detection results.

[0057] Furthermore, the first sealing body 61 and the second sealing body 62 are made of the same material, namely fluororubber. Using the same material (fluororubber) to manufacture the sealing bodies (including the first and second sealing bodies; when not distinguished by the ordinal numbers "first" and "second," the main body can be determined by the context. Similarly, the first and second sealing grooves are also made of the same material). With consistent material processing parameters, they can be integrally molded in one piece, ensuring no interface gap between the fitting section of the pipe 7 (the original first sealing body 61) and the mating sealing section (the original second sealing body 62), thus guaranteeing the integrity of the sealing structure during the production process.

[0058] When the sealing seat 1 is pressurized, both sections of the integrated sealing body undergo simultaneous elastic deformation. The mating sealing section fills the gap in the sealing seat 1, while the fitting section of the pipe 7 fits against the outer wall of the pipe 7. The recovery speed after deformation is consistent, preventing localized stress concentration due to differences in material properties. This ensures that the sealing pressure is evenly distributed across the entire continuous sealing ring, avoiding sealing failure in a single area. No categorization is required during inventory, and no material identification is needed during replacement. The integrated sealing body can be directly disassembled and reassembled as a whole, simplifying supply chain management, preventing sealing failure due to material mismatch, and reducing human error.

[0059] Fluororubber exhibits excellent resistance to organic solvents (isopropanol, ethanol), inert gases (helium), and weak acidic substances (such as trace amounts of organic acids produced by the oxidation of pipes). After long-term contact, its volume change rate is small, and it can still maintain good tensile strength without swelling, cracking, or aging. This ensures the service life of the seal in complex chemical environments and avoids seal failure caused by corrosion.

[0060] In this disclosure, the sealing seat 1 is made of 316L stainless steel. Compared to ordinary stainless steel (such as 304 stainless steel), 316L stainless steel has a dense passivation film that can withstand most non-oxidizing acids (such as hydrochloric acid and dilute sulfuric acid), organic acids (such as citric acid and acetic acid), alkaline solutions (such as sodium hydroxide), and organic solvents (such as ethanol and acetone). This prevents the sealing seat 1 from deforming due to corrosion and peeling, which could lead to increased gaps in the sealing body and subsequent leakage. No additional anti-corrosion coating (such as galvanizing or spraying) is required to adapt to the application scenario, effectively reducing the risk of seal failure due to corrosion of the sealing seat 1 and extending the maintenance cycle and service life of the entire sealing system.

[0061] Alternatively, the two sealing seats 1 are detachably connected by screws. Screw connection is a non-rigid fixation; before tightening the screws, the two sealing seats 1 can be slightly translated or their angles finely adjusted along the connection surface. This facilitates alignment of key structures such as the sealing grooves (e.g., the first / second sealing grooves 52 mentioned earlier) and limiting grooves, preventing misalignment and seal failure due to machining errors or assembly deviations. This allows for better adaptation to needs requiring disassembly.

[0062] The screws can be tightened using a torque wrench, ensuring a uniform and stable contact pressure between the two sealing seats 1. This compresses the flexible sealing body (such as fluororubber), causing it to tightly fill the sealing groove and adhere to the surface of the sealing seat 1, eliminating gaps. Simultaneously, it prevents deformation of the sealing seat 1 due to excessive pressure or loosening and leakage of the sealing surface due to insufficient pressure. When the sealing body (such as the first / second sealing body 62) needs replacement due to aging or wear, it is not necessary to damage the sealing seat 1 body. Simply unscrewing the screws allows the two sealing seats 1 to be separated, the old sealing body to be removed, and the new part to be replaced, reducing spare parts costs and maintenance time.

[0063] In other embodiments, a connection structure can also be used. That is, one sealing seat 1 has an elastic buckle, and the other sealing seat 1 has a retaining groove. Fixing is achieved by the buckle elastically deforming and engaging with the retaining groove. This allows for quick assembly and disassembly without tools, suitable for frequent maintenance scenarios. Alternatively, the two sealing seats 1 can be connected by pins. After aligning the pin holes on the sealing seats 1, a pin (such as a cylindrical pin or a conical pin) is inserted to restrict the relative displacement of the sealing seats 1.

[0064] In this disclosure, the air extraction port 4 is sealed to the sealing seat 1 via a detachable connection structure. The detachable structure integrates an elastic sealing element (such as an O-ring or gasket). During disassembly and assembly, the sealing element can fill the gap between the port and the sealing seat 1 through compression and deformation. Even after multiple disassembly and assembly, the elastic element can still provide stable sealing pressure, avoiding air leakage caused by wear of the mating surfaces.

[0065] It is worth noting that the air extraction port 4 is a component that is prone to wear and blockage. Therefore, when the port becomes worn, corroded, or blocked, it needs to be repaired to restore its function. Based on the detachable connection method, the entire sealing seat 1 does not need to be disassembled; only the port itself needs to be disassembled for replacement. Compared to welded, one-piece, non-detachable structures, this reduces maintenance time. Furthermore, different air extraction devices (such as small vacuum pumps and large negative pressure units) have different port specifications (diameter, connection method). The detachable structure allows "one sealing seat 1 to adapt to multiple ports," reducing design and spare parts costs.

[0066] In one embodiment, the air extraction port 4 is threadedly connected to the sealing seat 1. The fluororubber O-ring is squeezed as the thread is tightened, which can completely fill the thread gap and end face gap. Even if the port is replaced later, the O-ring can still restore its elastic seal after being tightened again, ensuring that the negative pressure does not leak.

[0067] In another embodiment, the suction port 4 uses a dedicated negative pressure quick connector to connect to the built-in one-way sealing valve core of the sealing seat 1. Upon insertion, the claws automatically lock and secure; upon removal, pressing unlocks the valve core, thereby achieving a negative pressure seal.

[0068] In another embodiment, an annular groove is machined at the mating end of the air extraction port 4 and the sealing seat 1, and an O-ring is placed in the groove; the outside is clamped with a stainless steel clamp (including a quick-release handle), and the contraction force of the clamp makes the port fit with the sealing seat 1, compressing the O-ring for sealing.

[0069] Under the technical concept of this disclosure, those skilled in the art can make flexible configurations.

[0070] The above specific embodiments further illustrate the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above are merely specific embodiments of the present invention and are not intended to limit the scope of protection of the present invention. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

[0071] Finally, it should be noted that this invention is not limited to the optional embodiments described above, and anyone can derive other various forms of products under the guidance of this invention. The specific embodiments described above should not be construed as limiting the scope of protection of this invention, which should be determined by the claims, and the specification can be used to interpret the claims.

Claims

1. A leak detection fixture for welded pipes in the vacuum chamber of a fusion device, characterized in that, It includes a pair of opposing sealing seats; each sealing seat has a cavity, and both ends of the sealing seat are provided with grooves adapted to the pipeline. When the two sealing seats are combined, the two cavities together form a detection chamber, and the two corresponding grooves together form a limiting groove for constraining the position of the pipeline; wherein, the detection chamber is formed as a sealing structure, and the sealing seat is provided with a vacuum port for connecting to an external vacuum device for evacuating the weld of the pipeline to be sealed and constrained.

2. The leak detection fixture for pipe welds in the vacuum chamber of a fusion device according to claim 1, characterized in that, The limiting groove is provided with a first sealing groove for accommodating a first sealing body, which is made of a flexible material so as to fit tightly against the pipe when compressed.

3. The leak detection fixture for pipe welds in the vacuum chamber of a fusion device according to claim 2, characterized in that, The first sealing groove has a square longitudinal section, and the contact surface between the first sealing body and the square groove is an arc surface.

4. The leak detection fixture for pipe welds in the vacuum chamber of a fusion device according to claim 1, characterized in that, The outer side of the groove is provided with a second sealing groove for accommodating a second sealing body, which is made of a flexible material so as to fit tightly against the sealing seat when compressed.

5. The leak detection fixture for pipe welds in the vacuum chamber of a fusion device according to claim 4, characterized in that, The longitudinal section of the second sealing groove is square, and the contact surface between the second sealing body and the square groove is an arc surface.

6. The leak detection fixture for pipe welds in the vacuum chamber of a fusion device according to any one of claims 1-5, characterized in that, The limiting groove is provided with a first sealing groove for accommodating the first sealing body, and the outer side of the groove is provided with a second sealing groove for accommodating the second sealing body. The first sealing groove is connected to the second sealing groove. The first sealing body and the second sealing body are integrally formed.

7. The leak detection fixture for pipe welds in the vacuum chamber of a fusion device according to claim 6, characterized in that, The first sealing body and the second sealing body are made of the same material, namely fluororubber.

8. The leak detection fixture for pipe welds in the vacuum chamber of a fusion device according to claim 1, characterized in that, The sealing seat is made of 316L stainless steel.

9. The leak detection fixture for pipe welds in the vacuum chamber of a fusion device according to claim 1, characterized in that, The two sealing seats are detachably connected by screws.

10. The leak detection fixture for pipe welds in the vacuum chamber of a fusion device according to claim 1, characterized in that, The air extraction port is sealed to the sealing seat via a detachable connection structure.

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