HDPE pipeline joint welding method and pipe joint assembly
By using electric weld joints and chain tightening methods in the HDPE pipeline joint area, the problems of insolid welding and stress concentration of large HDPE pipelines are solved, and higher welding quality and construction efficiency are achieved.
Patent Information
- Application Number
- CN202510103528.X
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-01-22
- Publication Date
- 2025-05-27
AI Technical Summary
The existing HDPE pipeline welding method cannot be applied to large HDPE pipelines, resulting in poor welding or concentrated stress leading to pipeline rupture.
The joint area is covered with an electric weld joint and tightened by a chain. The chain and the electric weld joint are in multi-point contact to ensure uniform stress distribution. At the same time, the replenishment welding area is reserved for extrusion welding during the welding process.
It effectively solves the problem of stress concentration during welding of large HDPE pipelines, improves welding quality and strength, reduces the risk of insolid welding, and improves construction efficiency.
Smart Images
Figure CN120038948A_ABST
Abstract
Description
Technical Field
[0001] The invention relates to the technical field of HDPE pipe welding, and in particular to a HDPE pipe joint welding method and a pipe joint assembly. Background Art
[0002] HDPE pipe (High Density Polyethylene) has been widely used in water supply and diversion systems, drainage systems and other fields because of its excellent properties, such as reliable connection, strong material impact resistance, outstanding crack resistance, aging resistance and corrosion resistance.
[0003] Whether a complete pipeline system is durable and safe enough often depends on the weakest part of the pipeline system. In the HDPE pipeline system, the weakest part is often the welding joint area of the HDPE pipeline. There are two commonly used HDPE pipeline welding methods: one is electric hot-melt socket welding, in which the electric-melt pipe fitting is first put on the pipe, and then a special welding machine is used to energize the electric-melt pipe fitting according to the set parameters (time, voltage, etc.), so that the inner surface of the electric-melt pipe fitting with the embedded heating wire and the outer surface of the pipe insertion end are melted, and the pipe and the pipe fitting are fused together after cooling; the other is hot-melt butt welding, in which the corresponding end faces of the two pipes or pipe fittings perpendicular to the pipe axis are contacted with the heating plate to heat and melt them, and after removing the heating plate, the molten end is quickly pressed and the pressure is maintained for a certain time until the joint cools down, so that a joint with a strength higher than the strength of the pipe body can be formed, thereby connecting the pipeline. However, when HDPE pipes are used in large-scale drainage systems, the diameter of large HDPE pipes (inner diameter ≥3000mm, single-section HDPE pipe deadweight ≥1t) is huge, and the above two traditional welding methods cannot firmly weld large HDPE pipes. If ordinary clamps are used to fix the HDPE pipes, stress concentration is likely to occur at the fixing point of the clamps, causing the HDPE pipes to rupture and damage. Therefore, a welding method suitable for large HDPE pipes is urgently needed. Summary of the invention
[0004] The purpose of the present invention is to overcome the shortcomings that conventional HDPE pipe welding methods are not suitable for large HDPE pipe welding, which easily causes large HDPE pipe joints to be welded loosely or causes stress concentration to damage the HDPE pipe, and to provide a HDPE pipe joint welding method and a pipe joint assembly.
[0005] In a first aspect, the present invention provides a method for welding a HDPE pipe joint, comprising the following steps: S1. Align the joint of the HDPE pipe, cover the joint area of the HDPE pipe with the electric fusion joint and reserve a repair welding area, the repair welding area is located between the head end and the tail end of the electric fusion joint; S2. Wrap the chain around the outer wall of the electric fusion joint and adjust the tightness of the chain so that the inner wall of the electric fusion joint is in close contact with the outer wall of the HDPE pipe; S3. Connect the electric fusion joint to the welding machine, weld the joint of the HDPE pipe, and remove the chain after the electric fusion joint is welded; S4. Perform extrusion welding on the repair welding area to complete the welding of the HDPE pipe.
[0006] The HDPE pipe joint welding method provided by the present invention overcomes the shortcomings of the traditional welding method that the welding is not firm enough due to the inability to provide sufficient contact pressure, or that the stress concentration is easily caused near the fastening point of the ordinary clamp.
[0007] This method uses an electric fusion joint to cover the joint area and uses a chain to tighten it. The chain and the electric fusion joint are in multi-point contact, which makes the stress distribution more uniform, and effectively solves the problem that stress concentration is easy to occur during the welding of large HDPE pipes and even causes the HDPE pipe to rupture; the chain is wrapped around the electric fusion joint so that the inner wall of the electric fusion joint and the outer wall of the HDPE pipe fit closely, thereby achieving more uniform heat transfer and contact pressure, effectively improving the welding quality, ensuring the welding strength, and reducing the risk of loose welding.
[0008] This method reserves a welding repair area when installing the electric fusion joint, which can effectively make up for the dimensional tolerance problem that may exist in the production process of the electric fusion joint, so that the produced electric fusion joint can adapt to HDPE pipes of different sizes, and significantly improve the adaptability and reliability of welding; using extrusion welding to perform supplementary welding in the area between the head and the tail of the electric fusion joint eliminates possible welding weak points in these areas, avoids potential risks caused by welding defects, and enables the weld to withstand higher internal pressure and external loads in long-term use; compared with the traditional method of fastening the electric fusion joint with ordinary clamps, the chain is easy to transport and install, which significantly reduces the difficulty of installation and transportation when welding large HDPE pipes and improves construction efficiency.
[0009] Preferably, before aligning the joint of the HDPE pipe in S1, the joint area of the HDPE pipe is first polished and cleaned.
[0010] Grinding and cleaning the HDPE pipe joint area before welding not only improves the surface quality of the welding area and enhances the adhesion of the electric fusion joint, but also reduces the occurrence of welding defects, optimizes the welding heat conduction effect, significantly improves the welding efficiency and reliability, and effectively extends the service life of the welding area.
[0011] Preferably, the head end and the tail end of the chain in S2 are connected to the clamping component, and the tightness of the chain is adjusted by the clamping component; The clamping component includes two fixing claws, one fixing claw is connected to the head end of the chain, and the other fixing claw is connected to the tail end of the chain; the two fixing claws are arranged in a mirror image, and the fixing claws include a base plate and a vertical plate connected to the base plate, the base plates of the two fixing claws are arranged opposite to each other and connected by bolts, the vertical plate abuts against the electric fusion joint, and at least two protrusions are arranged on the side of the vertical plate away from the electric fusion joint, and the protrusions can be inserted into the gap of the chain; the fixing claw also includes a fixing bolt, and the vertical plate is provided with at least one bolt hole, the position of the bolt hole corresponds to the gap of the chain, and the fixing bolt can be inserted into the bolt hole; the vertical plate is an arc-shaped structural member, and the curvature of the vertical plate matches the curvature of the HDPE pipe.
[0012] With this structural setting, the two fixing claws are set in a mirror image. The relative distance between the two fixing claws can be easily adjusted by connecting the bolts of the two base plates, thereby adjusting the tightness of the chain, flexibly adapting to HDPE pipes of different diameters, and ensuring that the chain evenly applies force on the outer wall of the electric fusion joint, so that the inner wall of the electric fusion joint fits tightly with the outer wall of the HDPE pipe, ensuring the stability of the joint and the welding quality during the welding process; the vertical plate is designed as an arc structure that matches the curvature of the HDPE pipe, which can fit the surface of the electric fusion joint more closely, reduce the gap and force concentration caused by the mismatch of the curvature, and further improve the stability and uniformity of the welding area; the raised part can be inserted into the gap of the chain, effectively preventing the chain from sliding or loosening when adjusting the tightness, and fixing the vertical plate and the chain by fixing bolts to prevent the chain from loosening or shifting during welding. The raised part and the fixing bolt form a double fixation, effectively ensuring the stability of the welding process.
[0013] Preferably, the position of the clamping component and the position of the repair welding area are staggered, and the position of the clamping component and the position of the repair welding area are staggered by at least 45°.
[0014] The position of the clamping component is staggered at least 45° from the repair welding area, so that the operating space of the repair welding area is not interfered by the clamping component, which is convenient for subsequent construction personnel to perform repair welding operations such as extrusion welding; on the other hand, since the hot fuse of the electric fusion joint is extended from the head and tail ends of the electric fusion joint and connected to the electric fusion welding machine through wires, arranging the clamping component to be staggered from the repair welding area can avoid the clamping component interfering with the electric fusion welding process, prevent the occurrence of dangerous situations such as short circuit, and improve the safety of the construction process.
[0015] Preferably, before adjusting the tightness of the chain in S2, a support ring is first installed in the joint of the HDPE pipe, the support ring comprising a ring body and a support rod located in the ring body, and the outer diameter of the ring body matches the inner diameter of the HDPE pipe joint; after tightening the chain, if it is found that there is still a gap between the chain and the electric fusion joint, a wedge is driven into the gap between the chain and the electric fusion joint until the gap between the chain and the electric fusion joint is eliminated.
[0016] When the diameter of the HDPE pipe is large, for example, more than 3000mm, the support ring can effectively support the inner wall of the pipe to prevent the HDPE pipe joint from elliptical deformation or collapse due to the looseness adjustment of the chain or other external forces during welding, thereby ensuring the roundness and stability of the welding area and the welding quality. In addition, since the support ring ensures the stability of the shape of the HDPE pipe joint, the operator can more conveniently adjust the contact between the electric fusion joint and the HDPE pipe, reduce the difficulty of alignment and fixation during welding, and improve operating efficiency. Inserting a wedge into the gap between the chain and the electric fusion joint can effectively eliminate the gap caused by the incomplete fit between the chain and the electric fusion joint. The wedge-shaped structure of the wedge can gradually fill the gap, so that the chain and the electric fusion joint form a closer contact, thereby ensuring that the surface of the electric fusion joint is evenly stressed and avoiding the decline in welding quality caused by insufficient local pressure.
[0017] Preferably, when welding the joint of the HDPE pipe in S3, the chain is further tensioned when the last one-third of the welding time point remains.
[0018] During the welding process, as the fusion joint is powered on and heated, the fusion joint and HDPE pipe materials will be slightly deformed or expanded due to heat softening. This deformation may reduce the tightness of the fit between the fusion joint and the HDPE pipe. In the last third of the welding time, further tensioning the chain can compensate for the looseness caused by material deformation, so that the fusion joint fits tightly to the HDPE pipe again, ensuring good contact in the welding area and avoiding uneven welding or insufficient welding strength.
[0019] Preferably, before removing the chain in S3, the electric fusion joint is cooled first, and the cooling time is not less than 45 minutes.
[0020] After the electrofusion joint is welded, the HDPE material in the welding area needs a certain amount of time to cool and solidify to restore its rigidity and strength. The cooling time is set to no less than 45 minutes to ensure that the material in the welding area is completely solidified, avoiding deformation or loose connection caused by the welding area not being completely cooled due to premature removal of the chain, thereby ensuring the welding quality.
[0021] Preferably, it also includes: S5. After the HDPE pipe is welded, a spark test is performed: Move the probe of the spark tester along the weld. The moving speed of the spark tester probe shall not exceed 40 cm / s and shall not be less than 5 cm / s. If sparks appear, repair the area where the sparks appear until all welds pass the spark test.
[0022] Spark testing is a reliable non-destructive testing method that can effectively detect defects in welds (such as holes, cracks, or incomplete welds). By performing spark testing on welds, it is possible to quickly determine whether there are leaks or defects in the weld, ensuring the tightness and integrity of the weld area; the probe movement speed of the spark tester is set between 5 cm / s and 40 cm / s to ensure the accuracy of the detection. If the probe moves too fast, smaller defects may be missed; if the speed is too slow, the detection efficiency may be affected. By limiting the range of movement speed, the test efficiency is improved and the reliability of the test results is guaranteed.
[0023] Preferably, the height of the repair welding area is 10CM~15CM.
[0024] The height of the repair welding area is set to 10cm~15cm, providing a reasonable and sufficient repair welding operation space. Such a height can effectively accommodate the welding materials and hot melt area required during the repair welding process, avoiding uneven or incomplete welding due to insufficient space, thereby ensuring welding quality.
[0025] In a second aspect, the present invention provides a pipe joint assembly, which is welded using the above-mentioned HDPE pipe joint welding method, comprising two HDPE pipes, wherein the joint of the two HDPE pipes is wrapped with an electric fusion joint, and at least two hot fuses are arranged on a side of the electric fusion joint in contact with the HDPE pipe, and the hot fuses are wound in a multi-row overlapping manner along the length direction of the electric fusion joint, and the electric fusion joint is connected to the HDPE pipe at the joint by electric hot fusion.
[0026] In the pipe joint assembly provided by the present invention, the hot fuse is wound in a multi-row overlapping manner along the length direction of the electric fusion joint, which effectively increases the area of the hot fuse in the welding area, thereby improving the uniformity of heat energy supply during welding, and making the welding connection more firm and reliable; wrapping the electric fusion joint at the joint of the HDPE pipe makes the welding connection coverage of the joint area more comprehensive, reduces the risk of fracture due to stress concentration during welding at the joint, and thus enhances the reliability of the joint connection.
[0027] 1. The HDPE pipe joint welding method provided by the present invention adopts an electric fusion joint to cover the joint area and uses a chain to fasten it. The chain and the electric fusion joint are in multi-point contact, so that the stress distribution is more uniform, which effectively solves the problem that stress concentration is easily generated during the welding process of large HDPE pipes and even causes the HDPE pipe to rupture; the chain is wrapped around the electric fusion joint so that the inner wall of the electric fusion joint and the outer wall of the HDPE pipe fit closely, thereby achieving more uniform heat transfer and contact pressure, effectively improving the welding quality, ensuring the welding strength, and reducing the risk of loose welding; 2. The HDPE pipe joint welding method provided by the present invention reserves a supplementary welding area when installing the electric fusion joint, which can effectively compensate for the dimensional tolerance problem that may exist in the production process of the electric fusion joint, so that the produced electric fusion joint can adapt to HDPE pipes of different sizes, and significantly improve the adaptability and reliability of welding; use extrusion welding to perform supplementary welding in the area between the head and the tail of the electric fusion joint, eliminate the possible welding weak points in these areas, avoid the potential risks caused by welding defects, and enable the weld to withstand higher internal pressure and external loads in long-term use; compared with the traditional method of fastening the electric fusion joint with ordinary clamps, the chain is easy to transport and install, which significantly reduces the difficulty of installation and transportation when welding large HDPE pipes, and improves construction efficiency.
[0028] 3. In the pipe joint assembly provided by the present invention, the hot fuse is wound in a multi-row overlapping manner along the length direction of the electric fusion joint, which effectively increases the area of the hot fuse in the welding area, thereby improving the uniformity of heat energy supply during welding, and making the welding connection more firm and reliable; wrapping the electric fusion joint at the joint of the HDPE pipe makes the welding connection coverage of the joint area more comprehensive, reducing the risk of fracture due to stress concentration during welding at the joint, thereby enhancing the reliability of the joint connection. BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Figure 1 A flow chart of the HDPE pipe joint welding method provided in Example 1; Figure 2 This is the welding state diagram of the electric fusion joint; Figure 3 This is the front view of the chain-wrapped electrofusion joint; Figure 4 This is a schematic diagram of the support ring located inside the HDPE pipe; Figure 5 It is a schematic diagram of the structure of the clamping component; Figure 6 It is a partial schematic diagram of the connection between the chain head end and tail end and the clamping component; Figure 7 This is a schematic diagram of an electric fusion joint; Figure 8 This is a schematic diagram of the spark test.
[0030] Markings in the figure: 1-Electric fusion joint, 11-Hot fuse, 2-Chain, 3-Clamping component, 31-Fixing claw, 311-Base plate, 312-Vertical plate, 313-Boss, 314-Bolt hole, 315-Fixing bolt, 4-Support ring, 41-Ring body, 42-Support rod, 5-Wedge, 10-Repair welding area, 100-HDPE pipe, 200-Welding machine, 300-Spark tester. DETAILED DESCRIPTION
[0031] The present invention is further described in detail below in conjunction with specific embodiments. However, this should not be understood as the scope of the above subject matter of the present invention being limited to the following embodiments, and all technologies realized based on the content of the present invention belong to the scope of the present invention.
[0032] Unless otherwise specified, in the description of the specific embodiments of the present invention, the terms indicating the orientation or position relationship such as "up", "down", "left", "right", "center", "inside", "outside", etc. are all based on the expression of the orientation or position relationship shown in the drawings, or are the orientation or position relationship when the invented product / equipment / device is usually used. These terms of orientation or position relationship are only for the convenience of describing the scheme of the present invention or simplifying the description in the specific embodiments, so as to facilitate the technicians to quickly understand the scheme, and do not indicate or imply that a specific device / component / element must have a specific orientation, or be constructed and operated in a specific position relationship, and therefore cannot be understood as a limitation on the present invention.
[0033] In addition, if the terms "horizontal", "vertical", "overhanging", "parallel" and the like appear, it does not mean that the corresponding devices / components / elements are required to be absolutely horizontal or vertical or overhanging or parallel, but may be slightly tilted or have deviations. For example, "horizontal" only means that its direction is more horizontal than "vertical", and does not mean that the structure must be completely horizontal, but may be slightly tilted. Alternatively, it can be simplified to mean that the corresponding devices / components / elements are set in directions such as "horizontal", "vertical", "overhanging", "parallel", etc., and can have an error / deviation of ±10% relative to the corresponding direction setting, more preferably an error / deviation within ±8%, more preferably an error / deviation within ±6%, more preferably an error / deviation within ±5%, and more preferably an error / deviation within ±4%. As long as the corresponding device / component / element is within the error / deviation range, it can still achieve its role in the scheme of the present invention.
[0034] In addition, the expressions “first”, “second”, “third”, etc., which appear in the terms, are merely used to distinguish the description of the same or similar components and should not be understood as emphasizing or implying the relative importance of specific components.
[0035] In addition, in the description of the embodiments of the present invention, "several", "plurality" and "a number" represent at least 2. It can be any number such as 2, 3, 4, 5, 6, 7, 8, 9, and even more than 9.
[0036] In addition, in the description of the technical solution of the present invention, unless otherwise clearly specified / defined / restricted, the terms "set", "install", "connect", "connected", "provided with", "laid", and "arranged" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection, and can be welding, riveting, bolting, threading, and other commonly used connection means in the field. This connection can be a mechanical connection, an electrical connection, or a communication connection; it can be a direct connection, or an indirect connection through an intermediate medium, and it can be the internal connection of two elements.
[0037] Example 1 This embodiment provides a HDPE pipe joint welding method, which is used to perform electric hot-melt welding on the outer wall of a joint of a large HDPE pipe (inner diameter ≥3000 mm, single-section HDPE pipe dead weight ≥1 t).
[0038] like Figure 1 As shown, the HDPE pipe joint welding method provided in this embodiment includes the following steps: S1. Grind and clean the joint area of the two sections of HDPE pipes 100 to be welded. Specifically, a grinder can be used to grind the joint of the two sections of HDPE pipes 100 to be welded. When cleaning, more volatile alcohol can be used to wipe the joint of the HDPE pipes 100 to be welded. Further, the electric fusion joint 1 can also be wiped and cleaned.
[0039] Use a crane to adjust the two sections of HDPE pipe 100 to be welded, align the joints of the HDPE pipe 100, and align the axes of the joints of the two sections of HDPE pipe 100 to be welded. Cover the joint area of the HDPE pipe 100 with the electric fusion joint 1 and reserve a repair welding area 10, such as Figure 2 , Figure 3 As shown, the repair welding area 10 is located between the head end and the tail end of the electric fusion joint 1. Figure 7 As shown, the electric fusion joint 1 can be a rectangular long strip of welding tape, and the length of the electric fusion joint 1 is slightly smaller than the circumference of the HDPE pipe 100. Further, the circumference of the HDPE pipe 100 minus the length of the electric fusion joint 1 is equal to 10CM~15CM, that is, Figure 3As shown, the height H of the repair welding area 10 is 10CM~15CM (in other embodiments, the number of repair welding areas 10 can be increased according to the diameter of the HDPE pipe 100. If the diameter of the HDPE pipe 100 is too large, the length of the electric fusion joint 1 can be appropriately reduced, and the number of repair welding areas 10 can be increased, for example, two repair welding areas 10 are set). The height of the repair welding area 10 is set to 10cm~15cm, which provides a reasonable and sufficient repair welding operation space. Such a height can effectively accommodate the welding materials and hot melt areas required in the repair welding process, avoid uneven or incomplete welding due to insufficient space, and thus ensure the quality of subsequent repair welding construction.
[0040] S2. First install the support ring 4 in the joint of the HDPE pipe 100. Figure 4 As shown, the support ring 4 includes a ring body 41 and a support rod 42 located in the ring body 41. The outer diameter of the ring body 41 matches the inner diameter of the HDPE pipe 100 joint, and the support rod 42 can form a cross support or other support methods in the ring body 41. When the diameter of the HDPE pipe 100 is large, for example, more than 3000mm, the support ring 4 can effectively support the inner wall of the pipe to prevent the HDPE pipe 100 joint from elliptical deformation or collapse due to the tightness adjustment of the chain 2 or other external forces during the welding process, thereby ensuring the roundness and stability of the welding area and the welding quality. In addition, since the support ring 4 ensures the stability of the shape of the HDPE pipe 100 joint, the operator can more conveniently adjust the contact between the electric fusion joint 1 and the HDPE pipe 100, reduce the difficulty of alignment and fixation during welding, and improve the operating efficiency.
[0041] Winding the chain 2 around the outer wall of the electrofusion joint 1, adjusting the tightness of the chain 2 so that the inner wall of the electrofusion joint 1 is in close contact with the outer wall of the HDPE pipe 100; Further, such as Figure 2 , Figure 3 , Figure 5 , Figure 6 As shown, in this embodiment, the head end and the tail end of the chain 2 are connected to the clamping component 3, and the tightness of the chain 2 is adjusted by the clamping component 3; Specifically, Figure 5 , Figure 6 As shown, the clamping member 3 includes two fixing claws 31, one fixing claw 31 is connected to the head end of the chain 2, and the other fixing claw 31 is connected to the tail end of the chain 2 (for example Figure 6 The fixing claw 31 in the middle and upper part can be connected to the head end of the chain 2. Figure 6The fixing claw 31 in the middle and lower part is connected to the tail end of the chain 2); the two fixing claws 31 are arranged in an upper and lower mirror image. The fixing claw 31 includes a bottom plate 311 and a vertical plate 312 connected to the bottom plate 311. In this embodiment, the vertical plate 312 is an arc-shaped structural member, and the curvature of the vertical plate 312 matches the curvature of the HDPE pipe 100.
[0042] The bottom plates 311 of the two fixing claws 31 are arranged opposite to each other and connected by bolts. The distance between the two bottom plates 311 can be quickly adjusted by adjusting the bolts connecting the two bottom plates 311, thereby adjusting the tightness of the chain 2.
[0043] The vertical plate 312 abuts against the electric fusion joint 1 , and at least two protrusions 313 are provided on a side of the vertical plate 312 facing away from the electric fusion joint 1 . The protrusions 313 can be inserted into the gaps of the chain 2 .
[0044] The fixing claw 31 also includes a fixing bolt 315, and the vertical plate 312 has at least one bolt hole 314, which can be Figure 5 The bolt hole 314 shown can be opened between the protrusion 313 and the bottom plate 311 . The position of the bolt hole 314 corresponds to the gap of the chain 2 . The fixing bolt 315 can pass through the gap of the chain 2 and be inserted into the bolt hole 314 .
[0045] With this structural setting, the two fixing claws 31 are arranged in a mirror image, and the relative distance between the two fixing claws 31 can be easily adjusted by connecting the bolts of the two bottom plates 311, thereby adjusting the tightness of the chain 2, flexibly adapting to HDPE pipes 100 of different pipe diameters, ensuring that the chain 2 evenly applies force on the outer wall of the electric fusion joint 1, so that the inner wall of the electric fusion joint 1 and the outer wall of the HDPE pipe 100 fit closely, ensuring the stability of the joint and the welding quality during the welding process; the vertical plate 312 is designed to match the curvature of the HDPE pipe 100 The matching arc structure can fit the surface of the electric fusion joint 1 more closely, reduce the gap and force concentration caused by the mismatch of the arc, and further improve the stability and uniformity of the welding area; the raised portion 313 can be inserted into the gap of the chain 2, effectively preventing the chain 2 from sliding or loosening when adjusting the tightness, and the vertical plate 312 is fixed to the chain 2 by the fixing bolt 315 to prevent the chain 2 from loosening or shifting during the welding process. The raised portion 313 and the fixing bolt 315 form a double fixation, which effectively ensures the stability of the welding process.
[0046] Further, such as Figure 4 As shown (the chain 2 wrapped around the outer wall of the electric fusion joint 1 is hidden for ease of observation), the position of the clamping component 3 is staggered with the position of the repair welding area 10, and the position of the clamping component 3 (the axis of symmetry of the two fixing claws 31) and the position of the repair welding area 10 (the central axis of the repair welding area 10) are staggered by an angle α, then ∠α≥45°.
[0047] The position of the clamping component 3 is offset from the repair welding area 10 by at least 45°, so that the operating space of the repair welding area 10 is not interfered by the clamping component 3, which is convenient for subsequent construction personnel to perform repair welding operations such as extrusion welding; on the other hand, since the hot fuse 11 of the electric fusion joint 1 is extended from the head and tail ends of the electric fusion joint 1 and is connected to the electric fusion welding machine 200 through electric wires, the clamping component 3 is set to be offset from the repair welding area 10, which can avoid the clamping component 3 interfering with the electric fusion welding process, prevent the occurrence of dangerous situations such as short circuits, and improve the safety of the construction process.
[0048] If a gap is found between the chain 2 and the electric fusion joint 1 after tightening the chain 2, a wedge 5 is driven into the gap between the chain 2 and the electric fusion joint 1 until the gap between the chain 2 and the electric fusion joint 1 is eliminated. Driving the wedge 5 into the gap between the chain 2 and the electric fusion joint 1 can effectively eliminate the gap caused by the incomplete fit between the chain 2 and the electric fusion joint 1. The wedge-shaped structure of the wedge 5 (one end is thicker and the other end is thinner) can gradually fill the gap, so that the chain 2 and the electric fusion joint 1 form a closer contact, thereby ensuring that the surface of the electric fusion joint 1 is evenly stressed and avoiding the degradation of welding quality caused by insufficient local pressure.
[0049] S3. Figure 2 As shown, the hot fuse 11 of the electric fusion joint 1 is connected to the welding machine 200 through an electric wire, and the joint of the HDPE pipe 100 is welded. After the welding of the electric fusion joint 1 is completed, the chain 2 is removed.
[0050] like Figure 7 As shown, two groups of thermal fuses 11 are arranged on one side of the electric fusion joint 1 close to the HDPE pipe 100 of the present embodiment. One group of thermal fuses 11 includes two thermal fuses 11 wound in a serpentine-like multi-row overlapping manner along the length direction of the electric fusion joint 1. The positions of the two groups of thermal fuses 11 can be as close to the edge of the electric fusion joint 1 as possible, and the thermal fuses 11 can extend from the side of the electric fusion joint 1. In the present embodiment, the thermal fuses 11 can be copper wires with good conductive effect.
[0051] like Figure 1 As shown, the left half of the electrofusion joint 1 can be welded first, and then the right half of the electrofusion joint 1 can be welded.
[0052] Furthermore, in this embodiment, when welding the joint of the HDPE pipe 100, the chain 2 is further tensioned when the last one-third of the welding time is left. For example, if the total welding time of the joint of the HDPE pipe 100 is 60 minutes, the chain 2 is further tensioned when the welding is performed for 40 minutes. During the welding process, as the electric fusion joint 1 is powered on and heated, the electric fusion joint 1 and the HDPE pipe 100 materials will be slightly deformed or expanded due to softening by heat. This deformation may cause the fit between the electric fusion joint 1 and the HDPE pipe 100 to decrease. When the chain 2 is further tensioned at the last one-third stage of the welding time, the looseness caused by the deformation of the material can be compensated, so that the electric fusion joint 1 can fit the HDPE pipe 100 tightly again, ensuring good contact in the welding area, and avoiding uneven welding or insufficient welding strength.
[0053] Furthermore, before removing the chain 2, the electrofusion joint 1 is cooled for a cooling time of not less than 45 minutes. After the electrofusion joint 1 is welded, the HDPE material in the welding area needs a certain amount of time to cool and solidify to restore its rigidity and strength. The cooling time is set to not less than 45 minutes, which can ensure that the material in the welding area is completely solidified, avoid deformation or loose connection caused by incomplete cooling of the welding area due to premature removal of the chain 2, thereby ensuring welding quality.
[0054] S4. Extrusion welding is performed on the repair welding area 10 to complete the welding of the HDPE pipe 100. Specifically, in S4, the repair welding area 10 can be welded by manually operating the extrusion welding machine, and the repair welding area 10 can be completely filled. After the extrusion welding is cooled, manual grinding is performed.
[0055] The HDPE pipe joint welding method provided in this embodiment overcomes the shortcomings of traditional welding methods that cannot provide sufficient contact pressure, resulting in loose welding, or easily cause stress concentration near the fastening point of ordinary clamps to damage the HDPE pipe.
[0056] This method uses an electric fusion joint 1 to cover the joint area and uses a chain 2 to tighten it. The chain 2 and the electric fusion joint 1 are in multi-point contact, which makes the stress distribution more uniform, and effectively solves the problem that stress concentration is easily generated during the welding of the large HDPE pipe 100 and even causes the HDPE pipe 100 to rupture; the chain 2 is wrapped around the electric fusion joint 1 so that the inner wall of the electric fusion joint 1 and the outer wall of the HDPE pipe 100 fit closely, thereby achieving more uniform heat transfer and contact pressure, effectively improving the welding quality, ensuring the welding strength, and reducing the risk of loose welding.
[0057] In this method, a repair welding area 10 is reserved when installing the electric fusion joint 1, which can effectively make up for the dimensional tolerance problem that may exist in the production process of the electric fusion joint 1, so that the produced electric fusion joint 1 can adapt to HDPE pipes 100 of different sizes, and significantly improve the adaptability and reliability of welding; using extrusion welding to perform supplementary welding in the area between the head and the tail of the electric fusion joint 1 (repair welding area 10), eliminates the welding weak points that may exist in these areas, avoids the potential risks caused by welding defects, and enables the weld to withstand higher internal pressure and external loads in long-term use; Compared with the traditional method of fastening the electric fusion joint 1 with ordinary clamps, the chain 2 is easy to transport and install, which significantly reduces the difficulty of installation and transportation when welding large HDPE pipes 100 and improves construction efficiency.
[0058] Further, such as Figure 1 The embodiment shown also includes: S5. Spark test is performed after the HDPE pipe 100 is welded: Figure 8 As shown, the probe of the spark tester 300 is moved along the weld, and the moving speed of the probe of the spark tester 300 does not exceed 40 cm / s and is not less than 5 cm / s. If sparks appear, the extrusion welding machine is operated to perform repair welding on the spark area until all welds pass the spark test.
[0059] Spark testing is a reliable non-destructive testing method that can effectively detect defects in welds (such as holes, cracks, or incomplete welds). By performing spark testing on welds, it is possible to quickly determine whether there are leaks or defects in the weld, ensuring the tightness and integrity of the weld area; the probe movement speed of the spark tester 300 is set between 5 cm / s and 40 cm / s to ensure the accuracy of the detection. If the probe moves too fast, smaller defects may be missed; if the speed is too slow, the detection efficiency may be affected. By limiting the range of movement speed, the test efficiency is improved and the reliability of the test results is guaranteed.
[0060] Example 2 The present embodiment provides a pipe joint assembly for connecting two adjacent large HDPE pipes 100. The pipe joint assembly provided in the present embodiment is welded using the HDPE pipe joint welding method provided in Example 1, and includes two HDPE pipes 100. The joint of the two HDPE pipes 100 is wrapped with an electric fusion joint 1. At least two hot fuses 11 are arranged on a side of the electric fusion joint 1 that contacts the HDPE pipe 100. The hot fuses 11 are wound in a multi-row overlapping manner along the length direction of the electric fusion joint 1. The electric fusion joint 1 and the HDPE pipe 100 are connected by electric hot fusion at the joint.
[0061] The pipe joint assembly provided in this embodiment is as follows: Figure 7As shown, the hot fuse 11 is wound in a multi-row overlapping manner along the length direction of the electric fusion joint 1, which effectively increases the area of the hot fuse 11 in the welding area, thereby improving the uniformity of heat energy supply during welding, and making the welding connection more firm and reliable; wrapping the electric fusion joint 1 at the joint of the HDPE pipe 100 makes the welding connection coverage of the joint area more comprehensive, reduces the risk of fracture due to stress concentration during welding at the joint, and thus enhances the reliability of the joint connection.
[0062] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principle of the present invention should be included in the protection scope of the present invention.
Claims
1. A method for welding a HDPE pipe joint, characterized in that: The following steps are involved: S1. Align the joint of the HDPE pipe (100), cover the joint area of the HDPE pipe (100) with the electrofusion joint (1) and reserve a repair welding area (10), the repair welding area (10) is located between the head end and the tail end of the electrofusion joint (1); S2. Wrap the chain (2) around the outer wall of the electrofusion joint (1), and adjust the tightness of the chain (2) so that the inner wall of the electrofusion joint (1) is in close contact with the outer wall of the HDPE pipe (100); S3. Connect the electric fusion joint (1) to the welding machine (200), weld the joint of the HDPE pipe (100), and remove the chain (2) after the electric fusion joint (1) is welded; S4. Extrusion welding is performed on the repair welding area (10) to complete the welding of the HDPE pipe (100).
2. A HDPE pipe joint welding method according to claim 1, characterized in that: Before aligning the joint of the HDPE pipe (100) in S1, the joint area of the HDPE pipe (100) is polished and cleaned.
3. A HDPE pipe joint welding method according to claim 1, characterized in that: The head end and tail end of the chain (2) in S2 are connected to the clamping component (3), and the tightness of the chain (2) is adjusted by the clamping component (3); The clamping component (3) comprises two fixing claws (31), one fixing claw (31) is connected to the head end of the chain (2), and the other fixing claw (31) is connected to the tail end of the chain (2); the two fixing claws (31) are arranged in a mirror image, the fixing claws (31) comprise a bottom plate (311) and a vertical plate (312) connected to the bottom plate (311), the bottom plates (311) of the two fixing claws (31) are arranged opposite to each other and connected by bolts, the vertical plate (312) abuts against the electric fusion joint (1), and at least two protrusions (313) are arranged on a side of the vertical plate (312) facing away from the electric fusion joint (1), and the protrusions (313) can be inserted into the gap of the chain (2); The fixing claw (31) further comprises a fixing bolt (315); the vertical plate (312) is provided with at least one bolt hole (314); the position of the bolt hole (314) corresponds to the gap of the chain (2); and the fixing bolt (315) can be inserted into the bolt hole (314); The vertical plate (312) is an arc-shaped structural member, and the curvature of the vertical plate (312) matches the curvature of the HDPE pipe (100).
4. A HDPE pipe joint welding method according to claim 3, characterized in that: The position of the clamping component (3) and the position of the repair welding area (10) are staggered, and the position of the clamping component (3) and the position of the repair welding area (10) are staggered by at least 45 degrees.
5. A method for welding a HDPE pipe joint according to claim 1, characterized in that: Before adjusting the tightness of the chain (2) in S2, a support ring (4) is first installed in the joint of the HDPE pipe (100), wherein the support ring (4) comprises a ring body (41) and a support rod (42) located in the ring body (41), and the outer diameter of the ring body (41) matches the inner diameter of the joint of the HDPE pipe (100); after tightening the chain (2), if it is found that there is still a gap between the chain (2) and the electric fusion joint (1), a wedge-shaped piece (5) is driven into the gap between the chain (2) and the electric fusion joint (1) until the gap between the chain (2) and the electric fusion joint (1) is eliminated.
6. A method for welding a HDPE pipe joint according to claim 1, characterized in that: When welding the joint of the HDPE pipe (100) in S3, the chain (2) is further tightened when the last one-third of the welding time is left.
7. A method for welding a HDPE pipe joint according to claim 1, characterized in that: Before removing the chain (2) in S3, the electric fusion joint (1) is cooled, and the cooling time is not less than 45 minutes.
8. A method for welding a HDPE pipe joint according to claim 1, characterized in that: Also includes: S5. After the HDPE pipe (100) is welded, a spark test is performed: the probe of the spark tester (300) is moved along the weld, and the moving speed of the probe of the spark tester (300) does not exceed 40 cm / s and is not less than 5 cm / s. If sparks appear, the spark area is repaired until all welds pass the spark test.
9. A method for welding a HDPE pipe joint according to any one of claims 1 to 8, characterized in that: The height of the repair welding area (10) is 10CM to 15CM.
10. A pipe joint assembly, characterized in that: Welding is performed using the HDPE pipe joint welding method described in any one of claims 1 to 9, comprising two HDPE pipes (100), wherein an electric fusion joint (1) is wrapped around the joint of the two HDPE pipes (100), at least two hot fuses (11) are arranged on a side of the electric fusion joint (1) in contact with the HDPE pipe (100), and the hot fuses (11) are wound in a multi-row overlapping manner along the length direction of the electric fusion joint (1), and the electric fusion joint (1) and the HDPE pipe (100) are connected by electric hot fusion at the joint.