Pipe gripping and sealing tool

Abstract

The utility model relates to nuclear power equipment leak detection technical field, concretely relates to a kind of pipe holding sealing tool, tool includes first sealing cover body and second sealing cover body;The inner side of first sealing cover body and second sealing cover body is equipped with sealing groove and pouring hole;One end of first sealing cover body and second sealing cover is hinged, and the other end is connected by bolt, after the buckling of first sealing cover body and second sealing cover, annular hollow cavity that will be formed in its inside is wrapped pipeline weld, and weld area is completely covered;Ensure the high adhesion and sealing reliability between tool and pipeline, effectively reduce the leakage risk caused by size deviation of traditional prefabricated sealing element.

Description

Technical Field

[0001] This utility model relates to the field of leak detection technology for nuclear power equipment, specifically to a pipe-clamping sealing tool. Background Technology

[0002] Nuclear power plants are characterized by a dense network of long, fixed pipes that extend vertically to the ceiling or horizontally through walls, connecting two or more buildings. This involves extensive pipe welding, resulting in multiple butt welds. Each weld requires sealing tests during manufacturing, installation, in-service inspection, and maintenance. According to the technical management requirements for nuclear power plant piping, these butt welds must undergo various non-destructive testing methods. The sealing requirements are extremely high, with acceptance standards generally on the order of <10⁻⁷ Pa·m³ / s, or even <10⁻¹⁰ Pa·m³ / s. Therefore, only vacuum helium leak detection technology can achieve this.

[0003] Vacuum helium leak detection of pipeline welds requires on-site sealing, local or individual sealing of the inspected point, and provides the prerequisite for subsequent vacuum extraction for weld helium leak detection. This often faces challenges such as tightly packed internal structures, complex facilities, limited space, high operational flexibility, and very limited time windows. However, in complex systems, after weld formation, there are no openings, making it impossible to seal individual points using conventional methods such as sleeves. Therefore, only a two-piece hinged tube-hugging method can be used, which presents a significant sealing challenge, as leaks are very likely to occur at the sealing interface or dead corners. For example, Chinese Patent Publication No. CN222913020U discloses a helium leak detection device for welds of irregularly shaped tube sheets in heat exchangers, which uses a combination of a sealing cap, a pressure plate, and a connecting plate. The sealing cap has a groove structure, with the groove covering the weld area and adapting to the irregularly shaped tube sheet, and an O-ring at the lower end. The pressure plate is connected to the connecting plate via fasteners (studs, nuts), pressing the sealing cap tightly onto the tube sheet to form a sealed cavity. This method relies on the elastic deformation of O-rings to fill the gap between the sealing cap and the tube sheet, achieving a seal through external pressure. While simple and reusable, this approach has significant limitations, such as… Figure 5 As shown, O-ring seals rely on planar fit. When the object being inspected is a circumferential curved weld of a cylindrical pipe, it is difficult to achieve a three-dimensional precise fit between the sealing cap and the pipe surface. This can easily create a gap (i.e., a "dead angle") at the edge of the curved surface, causing helium to seep in from the non-weld area and resulting in misjudgment of the test. Utility Model Content

[0004] To address the aforementioned issues, a pipe-hugging sealing fixture is provided. The annular hollow cavity formed by the engagement of the first and second sealing covers directly serves as the detection space for vacuum helium leak detection, completely covering the weld area. Simultaneously, the sealing grooves and casting holes on the inner sides of the first and second sealing covers constitute an in-situ forming mold for the sealing gasket. No additional molds or prefabricated seals are required; a customized sealing gasket can be formed between the outer surface of the pipe and the cover simply through an adhesive injection process. This ensures a high degree of fit and reliable sealing between the fixture and the pipe, effectively reducing the leakage risk caused by dimensional deviations in traditional prefabricated seals.

[0005] To address the problems of existing technologies, this utility model provides a pipe-clamping sealing fixture for vacuum helium leak detection of pipe butt welds. It includes a first sealing cover and a second sealing cover with a semi-circular arc structure. The inner arc surfaces of the first and second sealing covers match the arc of the outer surface of the pipe being inspected, and both the first and second sealing covers have sealing grooves on their inner sides for forming sealing gaskets. The outer surfaces of both the first and second sealing covers have casting holes communicating with the sealing grooves. One end of each sealing cover is hinged, and the other end is bolted together, allowing the first and second sealing covers to clamp onto the pipe. After the first and second sealing covers are engaged, an annular hollow cavity enclosing the pipe weld is formed inside.

[0006] Preferably, the sealing groove includes a semi-circular arc-shaped connecting part, and both sides of the connecting part are provided with mounting parts that communicate with the two ends of its axis.

[0007] Preferably, the first sealing cover and the second sealing cover have multiple casting holes, which are evenly distributed along the contour of the mounting portion.

[0008] The advantages of this utility model compared to the prior art are:

[0009] 1. This utility model utilizes the inner arc surfaces of the first and second sealing covers to tightly fit the outer surface of the pipe. The two covers are rotated to a locked position via a hinged structure and then tightened with bolts. Sealing colloid is injected into the sealing groove through the casting holes of the first and second sealing covers to achieve a seal on the hollow cavity. The detection equipment is connected to the hollow cavity, and a negative pressure environment is created by evacuation. The high permeability of helium is then used to detect leaks in the weld. If a defect exists in the weld, helium will enter the hollow cavity through the leak point, and the detection equipment will capture the signal, thus determining the weld's sealing performance. This ensures a high degree of fit and reliable sealing between the tooling and the pipe, effectively reducing the risk of leakage caused by dimensional deviations in traditional prefabricated seals.

[0010] 2. The annular hollow cavity formed by the first and second sealing covers of this invention, after being fastened together, directly serves as the detection space for vacuum helium leak detection, completely covering the weld area. Simultaneously, the sealing grooves and casting holes on the inner sides of the first and second sealing covers constitute an in-situ forming mold for the sealing gasket. No additional molds or prefabricated seals are required; a customized sealing gasket can be formed between the outer surface of the pipe and the cover simply through an adhesive injection process. This ensures a high degree of fit and reliable sealing between the tooling and the pipe, effectively reducing the leakage risk caused by dimensional deviations in traditional prefabricated seals. Attached Figure Description

[0011] Figure 1 This is a three-dimensional structural diagram of a pipe-holding sealing tool.

[0012] Figure 2 This is a three-dimensional structural diagram of the first and second sealing covers in a pipe-holding sealing fixture when they are open.

[0013] Figure 3 This is an exploded view of a pipe-holding sealing fixture.

[0014] Figure 4 A schematic diagram of the cross-sectional structure of the first and second sealing covers clamping a tubular mold in a pipe-clamping sealing fixture. Figure 1 .

[0015] Figure 5 This is a cross-sectional structural diagram of the tooling clamping the tubular mold using an O-ring in the existing technology.

[0016] Figure 6 This is a three-dimensional structural diagram of the first sealing cover in a pipe sealing fixture when the sealing gasket is formed by a sealing mold.

[0017] Figure 7 This is an exploded view of the first sealing cover, sealing gasket, and sealing mold in a pipe-holding sealing fixture.

[0018] Figure 8 A schematic diagram of the cross-sectional structure of the first and second sealing covers clamping a tubular mold in a pipe-clamping sealing fixture. Figure 2 .

[0019] Figure 9 This is a schematic diagram of the three-dimensional cross-sectional structure of the first and second sealing covers clamping the tubular mold in a pipe-clamping sealing fixture.

[0020] The numbers on the map are:

[0021] 1. First sealing cover; 11. Sealing gasket; 12. Sealing groove; 121. Connecting part; 122. Mounting part; 13. Pouring hole; 14. Bolt; 15. Hollow cavity; 16. Inspection port; 2. Second sealing cover; 3. Tubular mold; 4. Sealing mold; 5. Pipeline. Detailed Implementation

[0022] To further understand the features, technical means, and specific objectives and functions achieved by this utility model, the following detailed description of this utility model is provided in conjunction with the accompanying drawings and specific embodiments.

[0023] like Figures 1 to 5 , Figure 8 and Figure 9 As shown: A pipe-clamping sealing fixture for vacuum helium leak detection of the butt weld of a pipe 5 includes a first sealing cover 1 and a second sealing cover 2 with a semi-circular arc structure; the inner arc surfaces of the first sealing cover 1 and the second sealing cover 2 match the arc of the outer surface of the pipe 5 being tested, and the inner sides of the first sealing cover 1 and the second sealing cover 2 are provided with sealing grooves 12 for forming sealing gaskets 11; the outer surfaces of the first sealing cover 1 and the second sealing cover 2 are provided with casting holes 13 communicating with the sealing grooves 12; one end of the first sealing cover 1 and the second sealing cover is hinged, and the other end of the first sealing cover 1 and the second sealing cover is connected by bolts 14, so that the first sealing cover 1 and the second sealing cover 2 clamp onto the pipe 5, and after the first sealing cover 1 and the second sealing cover are fastened together, an annular hollow cavity 15 is formed inside to wrap around the weld of the pipe 5.

[0024] When using this pipe-clamping sealing fixture to perform vacuum helium leak testing on the butt weld of pipe 5, the first sealing cover 1 and the second sealing cover 2, which have a semi-circular arc structure, are first set on both sides of pipe 5. Utilizing the matching between the inner arc surfaces of the first sealing cover 1 and the second sealing cover 2 and the arc of the outer surface of the pipe 5 being tested, the inner arc surfaces of the first sealing cover 1 and the second sealing cover 2 are tightly fitted to the outer surface of pipe 5. The two covers are rotated to the snap-fit ​​state through the hinge structure, and then tightened by the bolt 14 at the other end of the connection structure, so that the first sealing cover 1 and the second sealing cover 2 are stably clamped on pipe 5. At this time, after the first sealing cover 1 and the second sealing cover 2 are snapped together, an annular hollow cavity 15 is formed inside, which completely covers the weld and its surrounding area. Subsequently, sealing colloid is injected into the sealing groove 12 through the pouring holes 13, which connect the outer surfaces of the first sealing cover 1 and the second sealing cover 2 to the sealing groove 12. The colloid cures within the sealing groove 12 to form a sealing gasket 11 that conforms to the contour of the outer surface of the pipe 5, thereby filling the gap between the first sealing cover 1 and the second sealing cover 2 and the pipe 5, thus sealing the hollow cavity 15. After sealing is completed, the detection equipment is connected to the hollow cavity 15. A negative pressure environment is created by evacuating the vacuum, and the high permeability of helium is used to detect leaks in the weld. If there is a defect in the weld, helium will enter the hollow cavity 15 through the leak point and be detected by the detection equipment, thereby determining the sealing performance of the weld.

[0025] The core advantage of this pipe-clamping sealing fixture lies in its dual function. Firstly, the annular hollow cavity 15 formed by the engagement of the first sealing cover 1 and the second sealing cover 2 directly serves as the detection space for vacuum helium leak detection, completely covering the weld area. Secondly, the sealing grooves 12 on the inner sides of the first and second sealing covers 1 and 2, together with the casting hole 13, constitute an in-situ forming mold for the sealing gasket 11. No additional molds or prefabricated seals are required; a customized sealing gasket 11 can be formed between the outer surface of the pipe 5 and the cover simply through an adhesive injection process. This ensures a high degree of fit and sealing reliability between the fixture and the pipe 5, effectively reducing the leakage risk caused by dimensional deviations in traditional prefabricated seals. The independent sealing space of the annular hollow cavity 15 provides a stable detection environment for helium leak detection, significantly improving the detection sensitivity for minute leaks. The device is simple to manufacture and features high sealing performance and low sealing cost. In application, it is highly operable and shortens the sealing detection cycle, facilitating helium leak detection of the butt weld of the pipe 5.

[0026] like Figures 1 to 3 and Figures 7 to 9 As shown: The sealing groove 12 includes a semi-circular arc-shaped connecting part 121, and mounting parts 122 that communicate with the two ends of its axis are provided on both sides of the connecting part 121.

[0027] When using this pipe-holding sealing fixture, the semi-circular connecting part 121 of the sealing groove 12 is adapted to the circumferential contour of the outer surface of the pipe 5, forming a basic sealing area surrounding the pipe 5. The two mounting plates are symmetrical to each other, and the two mounting parts 122 are C-shaped structures. The two ends of the C-shape of the mounting parts 122 are respectively connected to the two ends of the axis of the connecting part 121, forming a composite sealing groove 12 structure. When the sealing adhesive is injected into the sealing groove 12, after the adhesive enters from the pouring hole 13, it first fills the semi-circular connecting part 121, which is tightly fitted to the circumferential surface of the pipe 5. Then, it flows into the C-shaped mounting part 122 along the two ends of the axis of the connecting part 121, and expands to fill both sides of the circumference of the pipe 5, so that the cured adhesive can form a sealing gasket 11 that matches the sealing groove 12.

[0028] The semi-circular connecting part 121 ensures a basic seal in the circumferential direction of the pipe 5, while the C-shaped mounting parts 122 on both sides enhance the sealing coverage of the weld area through circumferential expansion and filling, effectively preventing helium leakage from the circumferential gap of the weld. The C-shaped opening structure ensures smooth flow of the colloid and provides circumferential restraint for the sealing gasket 11, preventing it from shifting during tooling engagement, thereby improving the fitting accuracy between the sealing gasket 11 and the outer surface of the pipe 5. This composite sealing groove 12 design enhances the circumferential sealing capability of the tooling, achieving uniform molding of the sealing gasket 11 across the entire area, providing a more reliable circumferential sealing guarantee for vacuum helium leak detection, and reducing the risk of missed detection due to weak local sealing during the testing process.

[0029] like Figures 1 to 3 and Figures 7 to 9 As shown: the first sealing cover 1 and the second sealing cover 2 have multiple casting holes 13, and the multiple casting holes 13 are evenly distributed along the contour of the mounting part 122.

[0030] During the injection of sealing colloid into the sealing groove 12, multiple evenly distributed injection holes 13 allow the colloid to enter the sealing groove 12 simultaneously from different positions, ensuring uniform flow and filling of the colloid within the sealing groove 12. Since the mounting part 122 is connected to the semi-circular connecting part 121, the colloid can smoothly fill the entire sealing groove 12 under pressure, including all corners of the connecting part 121 and the mounting part 122, avoiding local voids or insufficient filling. This uniform filling method results in a uniform density and complete structure for the cured sealing gasket 11, enabling better adhesion to the outer surface of the pipe 5, thereby effectively improving sealing performance.

[0031] The evenly distributed pouring holes 13 along the contour of the mounting portion 122 not only ensure uniform filling of the sealing adhesive but also improve injection efficiency and shorten the molding time of the sealing gasket 11. Simultaneously, the evenly distributed pouring holes 13 optimize the flow path of the adhesive within the sealing groove 12, reducing flow resistance and lowering pressure requirements during injection, further enhancing the ease of use and efficiency of the tooling. Furthermore, it strengthens the bond between the sealing gasket 11 and the sealing groove 12, improving the stability and durability of the sealing gasket 11 and extending the service life of the tooling.

[0032] like Figures 1 to 7 As shown: A method for forming a pipe-clamping sealing fixture, applied to the aforementioned pipe-clamping sealing fixture, includes the following steps:

[0033] S1. Prepare a tubular mold 3 that matches the outer surface of the pipe 5.

[0034] S2. Prepare the first sealing cover 1 and the second sealing cover 2. Process the inner arc surfaces of the first sealing cover 1 and the second sealing cover 2 according to the tubular mold 3 so that the inner arc surfaces of the first sealing cover 1 and the second sealing cover 2 are adapted to the tubular mold 3.

[0035] S3. The first sealing cover 1 and the second sealing cover 2 are respectively fastened onto the pipe 5 to be tested, and silicone is poured through the pouring hole 13 to form a sealing gasket 11 that matches the outer surface contour of the pipe 5.

[0036] S4. The first sealing cover 1 and the second sealing cover 2 are connected by a hinge structure, and the first sealing cover 1 and the second sealing cover 2 are fixed.

[0037] S5. Perform a sealing test on the sealing fixture.

[0038] like Figures 1 to 9 As shown: In step S1, the pipe 5 to be inspected first needs to be 3D scanned to generate a 3D model of a semi-circular arc surface that matches the outer surface contour of the pipe 5, obtain the curvature data of the pipe 5 to be inspected, and prepare a tubular mold 3 that matches the arc shape of the pipe 5 to be inspected based on the data.

[0039] like Figures 1 to 9 As shown: In step S3, the first sealing cover 1 is fastened to the pipe 5, and a sealing mold 4 is set at the sealing groove 12 position on its inner arc surface. Glue is poured into the sealing groove 12 through the pouring hole 13. After curing, a sealing gasket 11 that matches the sealing groove 12 is formed. The first sealing cover 1 is then removed.

[0040] like Figures 1 to 3 , Figures 6 to 9As shown: In step S3, the second sealing cover 2 is fastened to the pipe 5, and a sealing mold 4 is set at the sealing groove 12 position on its inner arc surface. Glue is poured into the sealing groove 12 through the pouring hole 13. After curing, a sealing gasket 11 that matches the sealing groove 12 is formed. The second sealing cover 2 is then removed.

[0041] like Figures 1 to 3 , Figures 6 to 9 As shown: In step S4, the other ends of the first sealing cover 1 and the second sealing cover 2 are fixed by bolts 14, so that the interior of the first sealing cover 1 and the second sealing cover 2 will form an annular hollow cavity 15 that wraps around the weld of the pipe 5.

[0042] like Figure 9 As shown: In step S5, a detection port 16 communicating with the internal hollow cavity 15 is opened on the outer surface of the first sealing cover 1 or the second sealing cover 2.

[0043] Overall working principle: When using this pipe-clamping sealing tool to perform vacuum helium leak detection on the butt weld of pipe 5, firstly, a three-dimensional scan of the pipe 5 to be tested is performed to generate a three-dimensional model of a semi-circular arc surface that matches the outer surface contour of pipe 5, obtain the curvature data of pipe 5, and prepare a tubular mold 3 that is consistent with the curvature of pipe 5 accordingly.

[0044] Then, a first sealing cover 1 and a second sealing cover 2 for clamping the pipe 5 are prepared, and the inner arc surfaces of the first sealing cover 1 and the second sealing cover 2 are processed according to the obtained data and the tubular mold 3 so that the inner arc surfaces can match the curvature of the outer surface of the pipe 5 being inspected.

[0045] Then, the first sealing cover 1 is fastened onto the pipe 5 to be tested, and a sealing mold 4 is set at the sealing groove 12 position on the inner arc surface of the first sealing cover 1. Glue is poured into the sealing groove 12 through the pouring hole 13. After curing, a sealing gasket 11 that matches the sealing groove 12 is formed. At this time, the first sealing cover 1 is removed.

[0046] Then, the second sealing cover 2 is fastened onto the pipe 5 to be tested, and a sealing mold 4 is set at the sealing groove 12 position on the inner arc surface of the second sealing cover 2. Glue is poured into the sealing groove 12 through the pouring hole 13. After curing, a sealing gasket 11 that matches the sealing groove 12 is formed. At this time, the second sealing cover 2 is removed.

[0047] After the sealing gasket 11 is formed, one end of the first sealing cover 1 and the second sealing cover 2 are connected by a hinge structure, and the other end is fixed by bolts 14, so that the first sealing cover 1 and the second sealing cover 2 are clamped onto the pipe 5, and the interior of the two forms an annular hollow cavity 15 that encloses the weld. At the same time, since the sealing gasket 11 is located inside the first sealing cover 1 and the second sealing cover 2, the sealing gasket 11 can seal the hollow cavity 15.

[0048] Finally, the hollow cavity 15 is tested for sealing performance through the detection port 16 on the first sealing cover 1 or the second sealing cover 2. The detection port 16 is connected to the vacuum system, and the vacuum pump is started to evacuate the hollow cavity 15, reducing the pressure inside the cavity to a predetermined vacuum level. The evacuation valve is then closed and maintained for a period of time, and the pressure change inside the cavity is monitored. If the pressure rise rate meets the requirements, it indicates that the tooling has good sealing performance and subsequent helium mass spectrometry leak detection can be performed. If the pressure rises too quickly, the forming quality of the sealing gasket 11 or the tightness of the bolt 14 connection needs to be checked, and adjustments made accordingly before retesting until the requirements for vacuum helium leak detection are met. During helium mass spectrometry leak detection, the weld area of ​​the pipe 5 to be tested is covered with a helium hood, and helium is filled into the hood. If there is a leak in the weld, the helium will enter the hollow cavity 15 through the leak point. The helium inside the hollow cavity 15 will be detected by the helium mass spectrometer leak detector, thereby determining the leak location and leakage rate of the weld and achieving high-precision detection of the butt weld of the pipe 5.

[0049] The above embodiments only illustrate one or more implementations of this utility model, and their descriptions are relatively specific and detailed, but they should not be construed as limiting the scope of protection of this utility model. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this utility model, and these all fall within the scope of protection of this utility model. Therefore, the scope of protection of this utility model should be determined by the appended claims.

Claims

1. A pipe-clamping sealing fixture for vacuum helium leak detection of pipe butt welds, characterized in that, It includes a first sealing cover and a second sealing cover with a semi-circular arc structure; The inner arc surfaces of the first and second sealing covers match the arc of the outer surface of the pipe being inspected, and both the first and second sealing covers have sealing grooves for forming sealing gaskets on their inner sides. Both the outer surfaces of the first and second sealing covers are provided with casting holes that communicate with the sealing groove. One end of the first sealing cover and the second sealing cover are hinged together, and the other end of the first sealing cover and the second sealing cover are connected by bolts, so that the first sealing cover and the second sealing cover are clamped on the pipe. After the first sealing cover and the second sealing cover are fastened together, an annular hollow cavity that wraps around the weld seam of the pipe will be formed inside.

2. The pipe-clamping sealing fixture according to claim 1, characterized in that, The sealing groove includes a semi-circular arc-shaped connecting part, and mounting parts that communicate with both ends of its axis are provided on both sides of the connecting part.

3. A pipe gripping and sealing tool as claimed in claim 2, wherein, The first and second sealing covers have multiple casting holes, which are evenly distributed along the contour of the mounting portion.

Images