A polymer-reinforced composite pipe butt welding fixture and welding method

Abstract

This invention belongs to the field of oil and gas gathering and transportation pipeline technology, and proposes a butt welding fixture and welding method for polymer-reinforced composite pipes. The butt welding fixture includes a sliding support and a pull rod. The outer wall of the sliding support has a positioning ring groove. A first component, a second component, and a third component, each including a slider component, are sleeved on both sides of the positioning ring groove. The slider component includes a support rod, one end of which is hinged to the outer wall of the sliding support, and the other end of which is hinged to the side wall of a movable rod. The side wall of the movable rod is connected to a baffle. Several movable rods have one end hinged to the outer ring side wall of a sliding ring block. The other end of the movable rod of the second component is connected to a heat conduction barrier ring. The other end of the movable rod of the third component is connected to a temperature sensor. The pull rod is axially connected to the sliding ring blocks of the first, second, and third components. The polymer-reinforced composite pipe butt welding fixture proposed in this invention achieves a gradual reduction of welding heat radiation and heat conduction, reduces the length of the blank area in the polymer reinforcement layer, and improves the bonding performance.

Description

Technical Field

[0001] This invention belongs to the field of oil and gas gathering and transportation pipeline technology, and specifically relates to a polymer-reinforced composite pipe butt welding fixture and welding method. Background Technology

[0002] Mechanical composite pipes are widely used in highly corrosive oil and gas gathering and transportation pipeline projects. However, since this type of pipe relies solely on the interference fit between the base lining pipes to maintain interlayer bonding, the risk of lining collapse is relatively high during use.

[0003] To address this issue, polymer-reinforced composite pipes have been introduced to the market. By adding a polymer reinforcement layer between the base lining layers, the interlayer bonding strength is significantly improved, thereby reducing the risk of lining collapse failure. Although this new type of composite pipe has obvious performance advantages, the presence of the interlayer polymer reinforcement layer also increases the difficulty of on-site welding. The high-temperature conduction and heat radiation during the welding process can cause the local temperature of the pipe to rise. Once the temperature exceeds the glass transition temperature of the polymer reinforcement layer material, it will affect its bonding performance and may even lead to carbonization and decomposition, resulting in complete failure.

[0004] Specifically, traditional welding methods involve high heat input (such as submerged arc welding), resulting in high weld center temperatures. Given the high thermal conductivity of metal pipes, it is difficult to ensure that the temperature of the polymer reinforcement layer material in areas close to the weld meets the standards. To address this, manufacturers currently mainly protect the polymer material from heat damage by extending the blank areas between the polymer reinforcement layers (extending them to over 230mm). However, this method not only sacrifices the bonding performance of a longer area at the pipe end, but also creates significant inconvenience for processing and removing the polymer layer due to the long blank areas.

[0005] In addition, Chinese patent CN114310020A discloses a butt welding method and apparatus for large-diameter bimetallic composite pipes. Specifically, the welding method includes steps such as cutting, alignment, positioning, installing a high-temperature resistant ceramic ring, adjusting the position, welding, air filling, stopping air blowing and quickly tightening, cooling and finishing. The butt welding apparatus includes an outer base pipe and an inner liner pipe. The cooling step is to ensure that the molten material is well cooled so that the cooled molten material can connect the two sets of outer base pipes and inner liner pipes.

[0006] However, the cooling methods described above suffer from response delays due to the thick wall of the base tube, making it impossible to quickly absorb sudden heat flows, and temperature fluctuations between layers are difficult to control accurately. Therefore, overcoming the shortcomings of these existing technologies is a pressing problem to be solved in this technical field. Summary of the Invention

[0007] To address the above problems, this invention proposes a polymer-reinforced composite pipe welding fixture, comprising: a sliding bracket and a pull rod, wherein a positioning ring groove is provided on the outer wall of the sliding bracket, and a first component, a second component, and a third component are sequentially sleeved on both sides of the positioning ring groove on the outer wall of the sliding bracket;

[0008] The first, second, and third components all include a slider component, which includes several support rods arranged in a circumferential array. One end of each support rod is hinged to the outer wall of the sliding bracket, and the other end of each support rod is respectively hinged to the side wall of a number of movable rods. The adjacent side walls of adjacent movable rods are connected to baffles. One end of each movable rod is hinged to the outer ring side wall of the sliding ring block, and the sliding ring block is slidably sleeved on the outer wall of the sliding bracket. The other end of each movable rod of the second component is connected to a heat conduction barrier ring, and the other end of each movable rod of the third component is connected to a temperature sensor.

[0009] The traction rod is axially connected to the sliding ring blocks of the first, second, and third components.

[0010] Furthermore, the sliding bracket includes a main support rod, a sliding wheel, and a positioning rod;

[0011] The outer wall of the main support rod is provided with a positioning ring groove, and both ends of the main support rod are provided with sliding wheels. One end of the main support rod is coaxially connected to one end of the positioning rod, and the other end of the positioning rod extends out of the inner cavity of the polymer-reinforced composite tube in the same direction as one end of the traction rod.

[0012] Furthermore, the slider component also includes a first positioning stop and a second positioning stop, both of which are located on the outer wall of the sliding bracket, and are located on both sides of the sliding ring block respectively.

[0013] Furthermore, the cross-section of the baffle adopts a triangular plate structure, with one inclined side of the baffle hinged to the circumferential sidewall of the movable rod, and the other inclined side of the baffle hinged to the inclined side of the adjacent baffle.

[0014] Furthermore, the heat conduction barrier ring has a circular fan-shaped cross-section, and the heat conduction barrier ring faces the sidewalls of the adjacent heat conduction barrier rings on both sides, with an outer groove and an inner groove respectively.

[0015] When the first positioning stop abuts against the sliding ring block, the outer wall of the outer groove of the heat conduction barrier ring engages with the inner wall of the inner groove of the adjacent heat conduction barrier ring.

[0016] Furthermore, the first component also includes a first elastic ring and a first connecting block;

[0017] The first component has a first connecting block between adjacent baffles. The outer ring sidewalls of several first connecting blocks and several movable rods are together sleeved on the first elastic ring. The inner ring sidewall of the first connecting block is hinged to the outer ring sidewalls of two adjacent baffles, and the connection point between the first connecting block and the first elastic ring is located between the two hinged baffles.

[0018] Furthermore, the third component also includes a second elastic ring and a second connecting block;

[0019] The third component has a second connecting block between each adjacent baffle. Several second connecting blocks and the outer ring sidewalls of the second ends of several movable rods are together sleeved on the second elastic ring. The inner ring sidewall of the second connecting block is hinged to the outer ring sidewalls of two adjacent baffles, and the connection point between the second connecting block and the second elastic ring is located between the two hinged baffles.

[0020] Furthermore, the baffle is made of composite ceramic material, and the outer wall of the baffle is coated with a reflective coating.

[0021] Furthermore, the heat conduction barrier ring is made of aluminum alloy and has a built-in heat-absorbing filler.

[0022] Furthermore, the distance between the first component and the positioning ring groove is 30 to 50 mm;

[0023] The distance between the second component and the positioning ring groove is 50 to 150 mm;

[0024] The distance between the third component and the positioning ring groove is 165 to 175 mm.

[0025] The present invention also proposes a method for welding polymer-reinforced composite pipes, including a polymer-reinforced composite pipe butt welding fixture as described above, and a control host. The welding method includes the following steps:

[0026] Slide the welding fixture into the inner cavity of the two polymer-reinforced composite tubes until the positioning ring groove coincides with the position to be welded;

[0027] The heat conduction barrier rings of the second component and the temperature sensor of the third component on both sides of the drive positioning ring groove are respectively bonded to the inner walls of the polymer-reinforced composite tubes on both sides;

[0028] A pulse welding machine is used to weld the butt joints of the polymer-reinforced composite pipes on both sides, and a temperature sensor is used to obtain the real-time temperature.

[0029] The control host adjusts the welding current and pulse frequency of the pulse welding host based on the real-time temperature to maintain the real-time temperature below or equal to the set threshold until the welding operation is completed.

[0030] Compared with the prior art, the embodiments of the present invention have at least the following advantages:

[0031] 1. The polymer-reinforced composite pipe welding fixture proposed in this invention combines baffles, heat conduction barrier rings, and temperature sensors in an orderly manner to gradually reduce welding heat radiation and heat conduction. While ensuring the quality of pipe butt welding, it achieves bidirectional isolation of welding heat conduction and heat radiation, avoiding thermal damage to the polymer reinforcement layer caused by high welding temperatures, reducing the length of the blank area of ​​the polymer reinforcement layer, effectively solving the welding problem of polymer-reinforced composite pipes, reducing the difficulty of removing the polymer layer at the pipe ends in the later stage, and indirectly improving the bonding performance of polymer-reinforced composite pipes. In addition, the folded slider component avoids the problem of wear caused by contact with the pipe material, and the outward expansion slider component plays a gradient heat insulation role, effectively supporting the smooth implementation of the heat insulation effect of the welding fixture.

[0032] 2. The polymer-reinforced composite pipe welding method proposed in this invention actively reduces heat source input from the source, thereby reducing the possibility of thermal damage to the polymer reinforcement layer material. At the same time, the pulse frequency and peak current density are appropriately adjusted by the control host according to the monitored temperature to further reduce the welding temperature and weaken the influence of welding heat source.

[0033] Other features and advantages of the invention will be set forth in the following description, and will be apparent in part from the description, or may be learned by practicing the invention. The objects and other advantages of the invention may be realized and obtained by means of the structures pointed out in the description and the drawings. Attached Figure Description

[0034] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0035] Figure 1 A schematic diagram of the polymer-reinforced composite pipe butt welding fixture in an embodiment of the present invention is shown;

[0036] Figure 2 A side view schematic diagram of the polymer-reinforced composite pipe welding fixture in an embodiment of the present invention is shown;

[0037] Figure 3 A schematic diagram of the first component in an embodiment of the present invention is shown;

[0038] Figure 4 A schematic diagram of the second component in an embodiment of the present invention is shown;

[0039] Figure 5 A schematic diagram of the third component in an embodiment of the present invention is shown;

[0040] Figure 6 A schematic diagram of the first component from the front view in an embodiment of the present invention is shown;

[0041] Figure 7 This diagram illustrates the usage state of the polymer-reinforced composite pipe welding fixture in an embodiment of the present invention. Figure 1 ;

[0042] Figure 8 This diagram illustrates the usage state of the polymer-reinforced composite pipe welding fixture in an embodiment of the present invention. Figure 2 .

[0043] In the diagram, 1. Sliding bracket; 101. Main support rod; 102. Sliding wheel; 103. Positioning rod; 2. Pull rod; 3. Positioning ring groove; 4. First component; 5. Second component; 6. Third component; 7. Sliding block; 701. Sliding ring block; 702. Movable rod; 703. Baffle; 704. Support rod; 705. First positioning stop; 706. Second positioning stop; 8. Heat conduction barrier ring; 801. External groove; 802. Internal groove; 9. Temperature sensor; 10. Control host; 11. First elastic ring; 12. First connecting block; 13. Second elastic ring; 14. Second connecting block;

[0044] 100, Polymer-reinforced composite pipe; 200, Butt welding fixture; 300, Overlay layer; 400, Polymer reinforcement layer; 500, Reinforcement layer blank area. Detailed Implementation

[0045] The following description provides many different embodiments or examples for implementing various features of the invention. The elements and arrangements described in the specific examples below are only for concise expression of the invention and are merely examples, not intended to limit the invention.

[0046] To make the objectives, technical solutions, and advantages of the embodiments of the present invention clearer, the technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0047] This invention provides a butt welding fixture for polymer-reinforced composite pipes, for use inside the cavity of a polymer-reinforced composite pipe 100. Figure 1 A schematic diagram of the polymer-reinforced composite pipe welding fixture in an embodiment of the present invention is shown. Figure 1 In the process, the polymer-reinforced composite pipe butt welding fixture includes: a sliding support 1, a pull rod 2, a first component 4, a second component 5, and a third component 6;

[0048] The sliding bracket 1 has a positioning ring groove 3 on its outer wall. The positioning ring groove 3 is located at the middle position in the axial direction of the sliding bracket 1. In actual use, it is used to determine the position of the tooling inside the polymer-reinforced composite tube 100.

[0049] exist Figure 2 In the example shown, the outer wall of the sliding bracket 1 is sequentially fitted with the first component 4, the second component 5, and the third component 6 on both sides of the positioning ring groove 3, that is, the distance between the first component 4, the second component 5, the third component 6 and the positioning ring groove 3 increases sequentially; for example, the distance between the first component 4 and the positioning ring groove 3 is 30 to 50 mm, the distance between the second component 5 and the positioning ring groove 3 is 50 to 150 mm, and the distance between the third component 6 and the positioning ring groove 3 is 165 to 175 mm.

[0050] The first component 4, the second component 5, and the third component 6 all include a slider component 7. Figure 3 In the example shown, the slider component 7 includes a sliding ring block 701, a movable rod 702, a baffle 703, and a support rod 704; a plurality of support rods 704 are arranged in a circumferential array about the sliding bracket 1, one end of the plurality of support rods 704 is hinged to the outer wall of the sliding bracket 1, and the other end of the plurality of support rods 704 is respectively hinged to the side wall of a plurality of movable rods 702, the adjacent side walls of adjacent movable rods 702 are connected to the baffle 703, one end of the plurality of movable rods 702 is hinged to the outer ring side wall of the sliding ring block 701, and the sliding ring block 701 is slidably sleeved on the outer wall of the sliding bracket 1;

[0051] refer to Figure 4 The other end of the movable rod 702 of several second components 5 is connected to the heat conduction barrier ring 8;

[0052] refer to Figure 5 The other end of the movable rod 702 of several third components 6 is connected to a temperature sensor 9;

[0053] Among them, the baffle 703 is a composite ceramic material with a composition of 82~88 mol% Al2O3 and 12~18 mol% ZrO2, and the outer wall of the baffle 703 is coated with a reflective coating. For example, the reflective coating is a yttrium-stabilized zirconium oxide coating with a coating thickness of 0.05~0.2 mm and an infrared reflectivity of ≥90%.

[0054] The traction rod 2 is axially connected to the sliding ring block 701 of the first component 4, the second component 5, and the third component 6.

[0055] The heat conduction barrier ring 8 is made of aluminum alloy with good thermal conductivity and has an axial length of 50 mm. It has a built-in heat-absorbing filler, which includes hydrated sodium thiosulfate (Na2S2O3·5H2O) and sheet graphene; wherein the graphene content is 0.5~2.5wt%.

[0056] In the actual use of the tooling in this application, the two polymer-reinforced composite tubes 100 to be welded are arranged coaxially, and the ends of the two polymer-reinforced composite tubes 100 maintain a certain gap for butt welding.

[0057] The tooling of this application is placed inside the polymer-reinforced composite tube 100. The sliding bracket 1 is adjusted to change its position until the gap between the positioning ring groove 3 and the two polymer-reinforced composite tubes 100 forms a coplanar state, ensuring that the first component 4, the second component 5, and the third component 6 on both sides of the positioning ring groove 3 are located inside the two polymer-reinforced composite tubes 100 respectively; thus keeping the position of the sliding bracket 1 fixed, the pull rod 2 is pulled to drive the sliding ring blocks 701 of the two sets of first components 4, two sets of second components 5, and two sets of third components 6 to change their positions synchronously along the axial direction of the sliding bracket 1. Figure 7 In the example shown, in the same slider component 7, one end of the support rod 704 is hinged to the outer wall of the sliding bracket 1 and is located on the right side of the sliding ring block 701. When the sliding ring block 701 is pulled to the right along the axial direction of the sliding bracket 1, the distance between the end of the support rod 704 hinged to the outer wall of the sliding bracket 1 and the sliding ring block 701 decreases, and the second end of the movable rod 702 moves outward away from the sliding bracket 1 until the outer wall of the heat conduction barrier ring 8 and the outer wall of the temperature sensor 9 are in contact with the inner wall of the polymer-reinforced composite tube 100. At this time, the baffle 703 connected to the side wall of the movable rod 702 also unfolds, and several baffles 703 form a division of the inner cavity of the polymer-reinforced composite tube 100, forming the outward expansion operation state of the tooling.

[0058] It should be further explained that when welding two polymer-reinforced composite tubes 100, the heat at the welding point is mainly transferred through heat radiation from the air inside the polymer-reinforced composite tube 100, and secondly through heat conduction through the polymer-reinforced composite tube 100 body.

[0059] In this application, a plurality of baffles 703 of the first component 4, the second component 5, and the third component 6 form a three-fold division of the inner cavity space of the polymer-reinforced composite tube 100, preventing the heat at the working point from being transferred to both sides of the polymer-reinforced composite tube 100.

[0060] The heat is absorbed from the inner wall of the polymer-reinforced composite tube 100 by the heat conduction barrier ring 8 of the second component 5, further blocking the heat transfer; and combined with the temperature sensor 9 of the third component 6, the temperature of the inner cavity of the polymer-reinforced composite tube 100 is monitored in real time.

[0061] After the welding operation is completed, when the sliding ring block 701 is pushed to move to the left along the axial direction of the sliding bracket 1, the distance between the end of the support rod 704 hinged to the outer wall of the sliding bracket 1 and the sliding ring block 701 increases, and the second end of the movable rod 702 moves inward toward the sliding bracket 1 until the outer wall of the heat conduction barrier ring 8 and the outer wall of the temperature sensor 9 are separated from the inner wall of the polymer reinforced composite tube 100 and reset. Then, the baffle 703 connected to the side wall of the movable rod 702 is also reset, canceling the division of the inner cavity of the polymer reinforced composite tube 100, forming the inward state of the tooling, and pulling the sliding bracket 1 out of the polymer reinforced composite tube 100.

[0062] The polymer-reinforced composite pipe butt welding fixture proposed in this invention, while ensuring the quality of pipe butt welding, achieves bidirectional isolation of welding heat conduction and heat radiation, avoids heat damage to the polymer reinforcement layer 400 caused by high welding temperature, reduces the length of the blank area 500 of the polymer reinforcement layer, effectively solves the welding problem of polymer-reinforced composite pipe 100, reduces the difficulty of removing the polymer layer at the pipe end in the later stage, and indirectly improves the bonding performance of polymer-reinforced composite pipe 100.

[0063] Correspondingly, an annular groove is formed on the outer ring sidewall of the sliding ring block 701. The cross-section of the annular groove adopts a right-angled triangular structure, and the hypotenuse of the cross-section of the annular groove forms a 30° angle with the axis of the sliding ring block 701. The first end of the movable rod 702 is hinged to the bottom of the annular groove, and the rotation angle range of the movable rod 702 is limited by the sidewall of the annular groove. By pushing and pulling the pull rod 2, the movable rod 702 can rotate within the range of 30° to 90° about the axis of the sliding ring block 701, thereby causing the outer diameter of the second end of the movable rod 702 to change with the movement of the movable rod 702.

[0064] exist Figure 2 In the example shown, the sliding bracket 1 includes a main support rod 101, a sliding wheel 102, and a positioning rod 103;

[0065] A positioning ring groove 3 is provided at the axial middle position of the outer wall of the main support rod 101. The first component 4, the second component 5, and the third component 6 are slidably connected to the outer wall of the main support rod 101. Both ends of the main support rod 101 are provided with sliding wheels 102 to facilitate positional movement within the inner wall of the polymer-reinforced composite tube 100. One end of the main support rod 101 is coaxially connected to one end of the positioning rod 103, and the other end of the positioning rod 103 extends out of the inner cavity of the polymer-reinforced composite tube 100 in the same direction as one end of the traction rod 2.

[0066] In this invention, the free ends of both the positioning rod 103 and the pull rod 2 extend out of the inner cavity of the polymer-reinforced composite tube 100, so as to facilitate manual adjustment of the position of the sliding bracket 1 and the state of the slider component 7. In addition, in actual use, the positioning rod 103 and the pull rod 2 can be relatively fixed by external clamping components, which further improves the ease of use of the tooling of this application.

[0067] Correspondingly, the slider component 7 also includes a first positioning stop 705 and a second positioning stop 706. The first positioning stop 705 and the second positioning stop 706 are both provided on the outer wall of the sliding bracket 1, and the first positioning stop 705 and the second positioning stop 706 are respectively provided on both sides of the sliding ring block 701, thereby limiting the axial sliding range of the sliding ring block 701.

[0068] refer to Figure 1 The first positioning stop 705 and the second positioning stop 706 are both located on the lower outer wall of the sliding bracket 1, and the pull rod 2 is located above the sliding bracket 1, so as to realize the staggered arrangement of the pull rod 2 with the first positioning stop 705 and the second positioning stop 706.

[0069] When the first positioning stop 705 abuts against the sliding bracket 1, the movable rod 702 and the axis of the sliding ring block 701 form a 30° angle, the tooling is in the retracted state, and the first component 4, the second component 5, and the third component 6 all maintain a certain gap with the inner wall of the polymer reinforced composite tube 100 to ensure the normal movement of the sliding bracket 1.

[0070] When the second positioning stop 706 abuts against the sliding bracket 1, the moving rod 702 and the axis of the sliding ring block 701 form a 90° angle, the tooling is in the outward expansion operation state, and the heat conduction barrier ring 8 of the second component 5 and the temperature sensor 9 of the third component 6 are in contact with the inner wall of the polymer reinforced composite tube 100.

[0071] refer to Figure 6 The cross-section of the baffle 703 adopts a triangular plate structure. One inclined side of the baffle 703 is hinged to the circumferential sidewall of the movable rod 702, and the other inclined side of the baffle 703 is hinged to the inclined side of the adjacent baffle 703 through a hinge member.

[0072] This allows the tooling to be in an outward expansion state, with several baffles 703 on the same slider component 7 forming a coplanar state and a circular dividing surface; when the tooling is in an inward retraction state, adjacent baffles 703 are folded together by hinges to allow several movable rods 702 to retract.

[0073] It should be further noted that the tooling provided in this application also includes several intermediate working states between the outward expansion working state and the inward retraction working state. The outer diameter of the dividing surface formed by the second end of the movable rod 702 in different intermediate working states is different, thereby meeting the needs of the tooling of this application for use in polymer reinforced composite pipes 100 with different inner diameters.

[0074] refer to Figure 4 The heat conduction barrier ring 8 has a circular fan-shaped cross-section. On the same second component 5, several heat conduction barrier rings 8 are arranged in a circumferential array about the sliding bracket 1. When the second component 5 is in the outward expansion operation state, several heat conduction barrier rings 8 form a sleeve structure, and the outer wall of several heat conduction barrier rings 8 is in contact with the inner wall of the polymer reinforced composite tube 100.

[0075] Correspondingly, the heat conduction barrier ring 8 has an outer groove 801 extending along the axial direction of the sliding bracket 1 on one side wall facing the adjacent heat conduction barrier ring 8, and an inner groove 802 extending along the axial direction of the sliding bracket 1 on the other side wall of the heat conduction barrier ring 8.

[0076] The outer groove 801 and the inner groove 802 are designed to fit together. When the first positioning stop 705 abuts against the sliding ring block 701, that is, when the tooling is in the retracted state, the outer wall of the outer groove 801 of the heat conduction barrier ring 8 engages with the inner wall of the inner groove 802 of the adjacent heat conduction barrier ring 8, so as to satisfy the conversion of several heat conduction barrier rings 8 from the retracted state to the outward expansion state. During the conversion of the tooling from the retracted state to the outward expansion state, the contact area between the outer wall of the outer groove 801 and the inner wall of the inner groove 802 gradually decreases; during the conversion of the tooling from the outward expansion state to the retracted state, the contact area between the outer wall of the outer groove 801 and the inner wall of the inner groove 802 gradually increases.

[0077] refer to Figure 3 The first component 4 also includes a first elastic ring 11 and a first connecting block 12;

[0078] In the same first component 4, a first connecting block 12 is provided between adjacent baffles 703. The outer ring sidewalls of several first connecting blocks 12 and several movable rods 702 are together sleeved on the first elastic ring 11. The inner ring sidewall of the first connecting block 12 is hinged to the outer ring sidewalls of two adjacent baffles 703, and the connection point between the first connecting block 12 and the first elastic ring 11 is located between the two baffles 703.

[0079] refer to Figure 5 The third component 6 also includes a second elastic ring 13 and a second connecting block 14;

[0080] In the same third component 6, a second connecting block 14 is provided between adjacent baffles 703. The outer ring sidewalls of several second connecting blocks 14 and several movable rods 702 are together sleeved on the second elastic ring 13. The inner ring sidewall of the second connecting block 14 is hinged to the outer ring sidewalls of two adjacent baffles 703, and the connection point between the second connecting block 14 and the second elastic ring 13 is located between the two hinged baffles 703.

[0081] By adding the first elastic ring 11 and the second elastic ring 13, the segmentation effect of the first component 4 and the third component 6 on the inner cavity space of the polymer-reinforced composite tube 100 is improved, thereby enhancing the sealing performance of adjacent spaces after segmentation.

[0082] refer to Figure 8 The present invention also discloses a polymer-reinforced composite pipe welding method, including a polymer-reinforced composite pipe butt welding fixture 200 as described above, and a control host 10. The method includes the following steps:

[0083] Slide the welding fixture 200 into the inner cavity of the two polymer-reinforced composite tubes 100 until the positioning ring groove 3 coincides with the position to be welded;

[0084] The heat conduction barrier ring 8 of the second component 5 and the temperature sensor 9 of the third component 6 on both sides of the drive positioning ring groove 3 are respectively bonded to the inner wall of the polymer reinforced composite tube 100 on both sides.

[0085] A pulse welding host is used to perform welding operations on the butt joints of the polymer-reinforced composite pipes 100 on both sides, and a temperature sensor 9 is used to obtain the real-time temperature. For example, the pulse welding host is used to perform TIG (Tungsten Inert Gas) welding, also known as tungsten inert gas welding, which is a welding method that uses a non-fusible tungsten electrode under the protection of an inert gas (such as argon). The control parameters of the pulse welding host are: peak current 40~80A, base current 15~25A, and pulse frequency 100~200Hz.

[0086] The control host 10 adjusts the welding current and pulse frequency of the pulse welding host based on the real-time temperature to maintain the real-time temperature less than or equal to a set threshold until the welding operation is completed; for example, the set threshold is 65°C.

[0087] In practical use, it was found that the welding method of the present invention reduces the welding current by 3-8A and increases the pulse frequency by 10-30Hz compared with conventional pulse welding.

[0088] It should be further noted that the base pipe of the polymer-reinforced composite pipe 100 mentioned in this invention is made of carbon steel low alloy steel, the lining is made of stainless steel, nickel-based iron and nickel-based alloy materials, and a weld overlay layer 300 with a length of 30mm to 50mm and a thickness of about 3mm is prefabricated at the pipe end. The polymer reinforcement layer 400 of the polymer-reinforced composite pipe 100 has a distance of 180mm to 200mm between it and the pipe end, and a reinforcement layer blank area 500 is reserved between the weld overlay layer and the polymer reinforcement layer.

[0089] The glass transition temperature (Tg) of the polymer reinforcement layer material is ≥110℃.

[0090] This invention, by adjusting parameters such as pulse frequency and peak current density based on real-time temperature, not only ensures the welding quality of the pipe, but also actively adjusts the welding current and heat input compared to traditional welding methods. This reduces the possibility of thermal damage to the polymer reinforcement layer 400 material from the source, further lowering the welding temperature and reducing the impact of the welding heat source.

[0091] To further illustrate the polymer-reinforced composite pipe welding method proposed in this invention, a polymer-reinforced composite pipe 100 with an outer diameter of 219.3 mm and a wall thickness of 10 mm made of pressure-bearing carbon steel L360 and 3 mm thick corrosion-resistant alloy 825 will be used as an example:

[0092] Among them, the polymer reinforcement layer 400 is made of epoxy resin adhesive, and the pipe end is prefabricated with a 30mm long and 3mm thick overlay layer 300.

[0093] In conventional welding methods, the distance between the polymer reinforcement layer at the pipe end and the pipe end is greater than 240mm, and the length of the blank area of ​​the polymer reinforcement layer is greater than 200mm. The commonly used welding method for butt welding is manual tungsten inert gas welding. The current is 80A~100A during the root pass welding, and the welding current is 100A~130A in other stages. Occasionally, polymer layer burn-off occurs during the welding process.

[0094] The welding method disclosed in this invention has a polymer reinforcement layer 400 distance of 190mm from the pipe end, a reinforcement layer blank area 500 length of 150mm, and uses ENiCrMo-3 welding material. Referring to Table 1, the specific welding method parameters are as follows:

[0095] Table 1 Welding method parameters

[0096]

[0097] Furthermore, the mechanical properties and corrosion resistance of the pipe after welding meet the requirements, and the polymer reinforcement layer 400 material is also undamaged.

[0098] The welding method of the present invention actively reduces the heat source input from the source, and the use of welding fixtures reduces the space of the reinforcement layer blank area 500 by more than 50mm, which greatly reduces the difficulty of cleaning the polymer at the pipe end in the later stage, and indirectly improves the overall bonding performance of the polymer reinforced composite pipe 100.

[0099] The polymer-reinforced composite pipe welding fixture proposed in this invention combines baffle 703, heat conduction barrier ring 8 and temperature sensor 9 in an orderly manner to gradually weaken the welding heat radiation and heat conduction, thereby avoiding heat damage to the polymer reinforcement layer caused by welding.

[0100] Among them, the design of Al2O3-ZrO2 composite ceramic baffle 703 combined with yttrium-stabilized zirconia coating improves the blocking of temperature rise caused by thermal radiation; the design of phase change heat absorption characteristics is realized by using sodium thiosulfate hydrate (Na2S2O3·5H2O) and graphene composite material, and the thermal conductivity of the heat conduction barrier ring 8 made of soft aluminum alloy is used to improve the efficiency of absorbing the heat conduction of welding, and further improve the blocking of temperature rise transmission.

[0101] By combining temperature sensor 9, pulse welding method and control host 10, a set threshold is set. Through real-time temperature monitoring of key locations, the welding method can achieve a rapid dynamic response to real-time temperature exceedance, so as to meet the final temperature control requirements.

[0102] In addition, the welding fixture 200 of the present invention has an outward expansion state and an inward retraction state, which ensures the convenience of using the welding fixture 200. The folding slider component 7 avoids the problem of wear caused by contact with the pipe. During welding, the outward expansion slider component 7 plays a gradient heat insulation role, which effectively supports the smooth implementation of the heat insulation effect of the welding fixture 200.

[0103] It should be further explained that, in this application, a baffle, a heat conduction barrier ring, and a temperature sensor are arranged in an orderly manner to gradually reduce the welding heat radiation and heat conduction within the inner cavity of the polymer-reinforced composite tube 100. Similarly, by sequentially installing a baffle, a heat conduction barrier ring, and a temperature sensor on both sides of the welding position of the polymer-reinforced composite tube 100, the gradual reduction of heat radiation from the outer environment of the polymer-reinforced composite tube 100 and the gradual reduction of heat conduction from the outer wall environment of the polymer-reinforced composite tube 100 can also be achieved. Those skilled in the art can consider the connection principle of this invention and practical applications, and any solution that achieves the principle of this invention is acceptable.

[0104] In the description of this invention, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include one or more of the stated features. In the description of this invention, "a plurality of" means two or more, unless otherwise explicitly specified. Furthermore, the terms "installed," "connected," and "linked" should be interpreted broadly; for example, they may refer to a fixed connection, a detachable connection, or an integral connection; they may refer to a mechanical connection, an electrical connection, or a connection that allows for communication; they may refer to a direct connection or an indirect connection through an intermediate medium. Those skilled in the art can understand the specific meaning of these terms in this invention according to the specific circumstances.

[0105] Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features; and these modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A polymer-reinforced composite pipe butt welding fixture, for use inside the cavity of a polymer-reinforced composite pipe (100), characterized in that, include: The sliding bracket (1) and the pull rod (2) are provided. The outer wall of the sliding bracket (1) is provided with a positioning ring groove (3). The first component (4), the second component (5) and the third component (6) are sequentially sleeved on both sides of the outer wall of the sliding bracket (1) in the positioning ring groove (3). The first component (4), the second component (5), and the third component (6) all include a slider component (7). The slider component (7) includes a plurality of support rods (704) arranged in a circular array. One end of the plurality of support rods (704) is hinged to the outer wall of the sliding bracket (1). The other end of the plurality of support rods (704) is respectively hinged to the side wall of a plurality of movable rods (702). The adjacent side walls of adjacent movable rods (702) are connected to baffles (703). One end of the plurality of movable rods (702) is hinged to the outer ring side wall of the sliding ring block (701). The sliding ring block (701) is slidably sleeved on the outer wall of the sliding bracket (1). The other end of the movable rods (702) of the plurality of second components (5) is connected to a heat conduction barrier ring (8). The other end of the movable rods (702) of the plurality of third components (6) is connected to a temperature sensor (9). The pull rod (2) is axially connected to the sliding ring block (701) of the first component (4), the second component (5), and the third component (6); The slider component (7) further includes a first positioning stop (705) and a second positioning stop (706); The cross-section of the baffle (703) adopts a triangular plate structure. One inclined side of the baffle (703) is hinged to the circumferential sidewall of the movable rod (702), and the other inclined side of the baffle (703) is hinged to the inclined side of the adjacent baffle (703). The heat conduction barrier ring (8) has a circular fan-shaped cross-section. The heat conduction barrier ring (8) has an outer groove (801) and an inner groove (802) respectively on the side walls of the adjacent heat conduction barrier rings (8) on both sides. When the first positioning stop (705) and the sliding ring block (701) abut against each other, the outer wall of the outer groove (801) of the heat conduction barrier ring (8) and the inner wall of the inner groove (802) of the adjacent heat conduction barrier ring (8) are engaged. The baffle (703) is made of composite ceramic material, and the outer wall of the baffle (703) is coated with a reflective coating. The heat conduction barrier ring (8) is made of aluminum alloy and has a built-in heat-absorbing filler.

2. The polymer-reinforced composite pipe butt welding fixture according to claim 1, characterized in that, The sliding bracket (1) includes a main support rod (101), a sliding wheel (102), and a positioning rod (103). The outer wall of the main support rod (101) is provided with a positioning ring groove (3). Both ends of the main support rod (101) are provided with sliding wheels (102). One end of the main support rod (101) is coaxially connected to one end of the positioning rod (103). The other end of the positioning rod (103) extends out of the inner cavity of the polymer-reinforced composite tube (100) in the same direction as one end of the traction rod (2).

3. The polymer-reinforced composite pipe welding fixture according to claim 2, characterized in that, The first positioning stop (705) and the second positioning stop (706) are both located on the outer wall of the sliding bracket (1), and the first positioning stop (705) and the second positioning stop (706) are respectively located on both sides of the sliding ring block (701).

4. The polymer-reinforced composite pipe welding fixture according to claim 3, characterized in that, The first component (4) further includes a first elastic ring (11) and a first connecting block (12); The first component (4) is provided with a first connecting block (12) between adjacent baffles (703). The outer ring sidewalls of several first connecting blocks (12) and several movable rods (702) are connected together to the first elastic ring (11). The inner ring sidewall of the first connecting block (12) is hinged to the outer ring sidewall of two adjacent baffles (703), and the connection point between the first connecting block (12) and the first elastic ring (11) is located between the two hinged baffles (703).

5. The polymer-reinforced composite pipe welding fixture according to claim 4, characterized in that, The third component (6) also includes a second elastic ring (13) and a second connecting block (14); The third component (6) is provided with a second connecting block (14) between adjacent baffles (703). The outer ring sidewalls of several second connecting blocks (14) and several movable rods (702) are connected together to the second elastic ring (13). The inner ring sidewall of the second connecting block (14) is hinged to the outer ring sidewalls of two adjacent baffles (703), and the connection point between the second connecting block (14) and the second elastic ring (13) is located between the two hinged baffles (703).

6. The polymer-reinforced composite pipe butt welding fixture according to claim 1, characterized in that, The distance between the first component (4) and the positioning ring groove (3) is 30 to 50 mm; The distance between the second component (5) and the positioning ring groove (3) is 50 to 150 mm; The distance between the third component (6) and the positioning ring groove (3) is 165 to 175 mm.

7. A method for welding polymer-reinforced composite pipes, characterized in that, The welding method includes a polymer-reinforced composite pipe butt welding fixture as described in any one of claims 1-6, and a control host (10). The welding method includes the following steps: Slide the welding fixture (200) into the inner cavity of the two polymer-reinforced composite tubes (100) until the positioning annular groove (3) coincides with the position to be welded; The heat conduction barrier ring (8) of the second component (5) on both sides of the drive positioning ring groove (3) and the temperature sensor (9) of the third component (6) respectively form a bond with the inner wall of the polymer reinforced composite tube (100) on both sides; A pulse welding machine was used to weld the butt joints of the polymer-reinforced composite tubes (100) on both sides, and a temperature sensor (9) was used to obtain the real-time temperature. The control host (10) adjusts the welding current and pulse frequency of the pulse welding host based on the real-time temperature, and maintains the real-time temperature less than or equal to the set threshold until the welding operation is completed.

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