A method for repairing bamboo-wrapped composite pipe

Abstract

The present invention discloses a method for repairing a bamboo-wrapped composite pipe, including a local repair method and a pipe section replacement repair method. The local repair method. The present invention provides a local repair method and a pipe section replacement repair method so as to perform repairs under different conditions of pipe damage. The local repair method can be adopted when the damaged area of ​​the bamboo-wrapped composite pipe does not exceed 25% of the pipe circumference, which can reduce the loss of materials, reduce the time for repair construction and pipe deactivation, and minimize the impact on pipe transportation. When the pipe section replacement repair method is adopted, the repair can be completed without other large auxiliary devices, eliminating the time for transportation and deployment of large equipment, reducing the repair time and repair cost, and allowing the repair work to be carried out flexibly. The bamboo-wrapped composite pipe repair method provided by the present invention requires a small number of repair personnel, can complete the repair in 2-4 hours while ensuring the quality of the repair, and has a short repair time and little impact on the normal operation of the pipeline.

Description

Technical Field

[0001] The invention belongs to the technical field of pipeline repair, and in particular relates to a repair method for a bamboo-wrapped composite pipeline. Background Art

[0002] Bamboo-wrapped composite pipe is a new type of bio-based pipe that uses bamboo as the base material, adopts a mechanical winding method, uses resin as an adhesive, and is processed and formed using a winding process. It can replace traditional pipes such as spiral welded pipes and prestressed steel cylinder concrete pipes, and can be widely used in agricultural water, petrochemical, urban construction, housing, storage and transportation, and other fields.

[0003] When bamboo wrapped composite pipes are used as high-pressure water supply pipes, if small cracks, gaps or large-scale pipe bursts occur in the pipes, it will cause pressure relief and water leakage, affecting the normal water supply. Therefore, the pipes need to be repaired quickly to ensure normal water supply.

[0004] Patent application number 2019102112254 discloses a trenchless pipeline point repair method based on a two-component repair resin. The invention provides a trenchless pipeline point repair method based on a two-component repair resin, which only performs local reinforcement repair on the damaged position, which is more targeted and has a fast construction speed. However, its repair method is different from that of the present invention, and the repair object is not suitable for bamboo-wrapped composite pipes. Summary of the invention

[0005] In order to solve the above technical problems, the present invention provides a method for repairing a bamboo-wrapped composite pipe, and provides a method for repairing a bamboo-wrapped composite pipe when the pipe is damaged to different degrees.

[0006] The present invention is achieved through the following technical solutions.

[0007] A method for repairing a bamboo-wrapped composite pipe includes a local repair method and a pipe section replacement repair method; the local repair method includes the following steps:

[0008] A1: Drain the medium in the pipeline and dry the inside of the pipeline. Then mark the damaged part of the pipeline and draw a line on the outside of the edge of the damaged part. Cut obliquely along the drawn line to the inner lining of the pipeline and avoid cutting the inner lining of the pipeline.

[0009] A2: After cutting, remove the structural layer of the pipe, and then remove the remaining bamboo strips at the corners of the cut. If there are extended cracks in the lining, expand the groove to expose all the damaged parts of the lining. After removing the structural layer, grind and clean the surface of the lining.

[0010] A3: Apply adhesive A evenly on the surface of the inner lining, cut the bamboo fiber felt and knitted felt to the same shape as the groove formed by cutting, lay the bamboo fiber felt flat on the inner lining after applying adhesive A, apply adhesive A on the upper surface of the bamboo fiber felt after adhesive A is cured, and then use knitted felt for continuous laying. Each time a layer of knitted felt is laid, a layer of adhesive A needs to be applied on the surface of the knitted felt, and then the next layer of knitted felt is laid. The knitted felt laying process needs to be continuous and uninterrupted until the outermost layer of knitted felt laid on the pipe is flush with the original pipe body; after adhesive A is cured and stable, grind the surface of the repaired part and the circumference of the nearby pipe body; wrap the knitted felt along the circumference of the damaged part and the nearby pipe body and wrap it tightly with a mesh cloth. The winding process needs to be continuous and uninterrupted, and finally wrap it tightly with a mesh cloth. The repair can be completed when the temperature of the repaired part drops to the ambient temperature; for bamboo-wrapped composite pipes with high internal pressure, add a clamp or half joint to the repaired part after repair to improve the pressure resistance;

[0011] The pipe joint replacement and repair method comprises the following steps:

[0012] B1: Drain the medium in the pipeline until the inside of the pipeline is dry, find the location of large-scale damage in the pipeline, draw a line 40-50cm outside the edge of the damaged part on both sides as the cutting line, measure the length of the pipe body between the cutting lines on both sides, cut the pipe body along the drawn position, draw a line mark 10-20cm back from the cut end face of the original pipe section, and cut obliquely along the drawn position to the end face to expose the lining and avoid cutting the lining of the pipeline. Remove all the structural layers on the surface of the lining, remove the residual structural layers and bamboo strips at the corners, and only keep the lining to obtain the inclined surface B on the original pipe section.

[0013] B2: Take a bamboo-wrapped composite pipe of the same specification as the damaged pipe, cut a pipe section of the same length as the pipe section cut off in step B1 to obtain a replacement section, draw a line mark 10-20 cm back from the cut end face of the replacement section, bevel cut along the marked position to the end face to the lining and expose the lining, remove all the structural layers on the surface of the lining, obtain a bevel C on the replacement section, align and dock the end faces of the replacement section with the corresponding end faces of the original pipe section, polish the lining at the connection between the replacement section and the original pipe section, evenly apply adhesive B to the lining joint between the replacement section and the original pipe section, wrap the joint with bamboo fiber felt for 2-3 layers, and then use knitted felt for continuous wrapping, with each wrapping A layer of knitted felt, the surface of the knitted felt needs to be coated with a layer of adhesive B, and then the next layer of knitted felt is wrapped. The winding process of the knitted felt needs to be continuous and cannot be interrupted. The outermost layer needs to be wrapped with another layer of knitted felt, and the wrapping range of the knitted felt needs to reach at least 30cm on both sides of the joint. Finally, wrap it with 2-3 layers of mesh cloth and wrap it tightly. The thickness of the knitted felt wrapped at the joint needs to be greater than the thickness of the original bamboo pipe body, and the thickness should be the same as the wall thickness of the pipe. After the adhesive B is cured, it is polished and smoothed. The repair can be completed when the temperature of the repaired area drops to room temperature. For bamboo-wrapped composite pipes with high internal pressure, add a clamp or half joint at the repaired area to improve the pressure resistance after repair.

[0014] Preferably, in the step A1, a line is drawn at a position extending 5-10 cm from the outer side of both sides of the edge of the damaged part; and the bevel cutting angle is controlled at 30-45°.

[0015] Preferably, in step A3, the knitted felt is wound along the circumferential direction of the damaged part and the nearby tube body and tightly wrapped with mesh cloth, the number of knitted felt winding layers is 16 layers, and the wrapping range of the knitted felt needs to at least reach a range extending 30 cm outward from the damaged part of the tube body.

[0016] Preferably, the preparation method of the adhesive A comprises the following steps: preparing a resin raw material of corresponding mass, adding a promoter to the resin raw material and stirring, and adding an initiator after 2-6 minutes and stirring evenly.

[0017] Preferably, in the adhesive A, the mass proportion of the initiator is 0.75-1.5%, the mass proportion of the accelerator is 0.3-0.6%, the resin raw material is 7501 type unsaturated resin, and the accelerator is cobalt salt.

[0018] Preferably, the preparation method of the adhesive B comprises the following steps: preparing a resin raw material of corresponding mass, adding a promoter to the resin raw material and stirring, and adding an initiator after 2-6 minutes and stirring evenly; the mass of the initiator is 0.75-1.5% of the mass of the resin raw material, and the mass of the promoter is 0.3-0.6% of the mass of the resin raw material; the resin raw material is 7501 type unsaturated resin, and the promoter is a cobalt salt.

[0019] Preferably, in step B1, the bevel cutting angle is 30-45°, and the exposed lining length is 10-15 cm.

[0020] Preferably, in step B2, the number of continuous winding layers of the knitted felt is 16 layers, and the overlapping width between the knitted felts is 2-3 cm.

[0021] Preferably, the local repair method is adopted when the damaged area of ​​the bamboo wrapped composite pipe does not exceed 25% of the circumference of the pipe; the pipe segment replacement repair method is adopted when the damaged area of ​​the bamboo wrapped composite pipe exceeds 25% of the circumference of the pipe and cannot be solved by the local repair method.

[0022] The beneficial effects of the present invention are:

[0023] The present invention provides a local repair method and a pipe segment replacement repair method, so as to perform repairs under different circumstances of pipeline damage. The local repair method can be used when the damaged area of ​​the bamboo-wrapped composite pipeline does not exceed 25% of the circumference of the pipeline, which can reduce material loss, reduce the time for repair construction and pipeline downtime, and minimize the impact on pipeline transportation. When the pipe segment replacement repair method is used, the repair can be completed without other large auxiliary devices, eliminating the transportation and deployment time of large equipment, reducing the repair time and repair cost, and allowing the repair work to be carried out flexibly. The bamboo-wrapped composite pipeline repair method provided by the present invention requires a small number of repair personnel, can complete the repair in 2-4 hours while ensuring the quality of the repair, and the repair time is short, with little impact on the normal operation of the pipeline. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Figure 1 is a flow chart of the local repair method of the present invention;

[0025] Figure 2 It is a flow chart of the pipe joint replacement and repair method of the present invention;

[0026] Figure 3 is a repair schematic diagram of the local repair method of the present invention;

[0027] Figure 4 is a schematic diagram of the local repair method of the present invention after repair;

[0028] Figure 5 It is a cutting schematic diagram of the pipe segment replacement and repair method of the present invention;

[0029] Figure 6 It is a schematic diagram of pipe segment replacement in the pipe segment replacement and repair method of the present invention;

[0030] Figure 7 It is a schematic diagram of the pipe segment after repair by the pipe segment replacement and repair method of the present invention;

[0031] In the figure: 1- damaged point, 2- processed groove, 3- inclined plane A, 4- cutting line, 5- original pipe section, 51- inclined plane B, 6- replaced section, 61- inclined plane C, 7- inner layer of pipe, 8- outer layer of pipe DETAILED DESCRIPTION

[0032] The technical solution of the present invention is further described below, but the scope of protection claimed is not limited to the description.

[0033] Embodiment 1:

[0034] like Figures 1 to 7 As shown, a method for repairing a bamboo-wrapped composite pipe includes a local repair method and a pipe segment replacement repair method. The local repair method includes the following steps:

[0035] A1: Drain the medium in the pipeline until the inside of the pipeline is dry, mark the damaged part of the pipeline (damage point 1, the same below), draw a line on the outside of the edge of the damaged part, and use a cutting machine to cut obliquely along the drawn position to the pipeline lining (pipeline inner layer 7, the same below) to obtain the inclined surface A3, and avoid cutting the pipeline lining.

[0036] A2: After the cutting is completed, use a woodworking push knife and a hammer to remove the structural layer of the pipe (the outer layer of the pipe 8, the same below), and then use a utility knife to remove the remaining bamboo strips at the corners of the cut. If there are extended cracks in the lining, expand the groove to expose all the damaged parts of the lining. After the structural layer is removed, grind and clean the surface of the lining to obtain the processed groove 2.

[0037] A3: Use a brush to evenly apply adhesive A on the surface of the lining, use scissors to cut the bamboo fiber felt and knitted felt into the same shape as the processing groove 2 formed by cutting, and lay the bamboo fiber felt flat on the lining after applying adhesive A. After adhesive A solidifies, apply adhesive A on the upper surface of the bamboo fiber felt, and then use knitted felt to lay it continuously. For each layer of knitted felt, a layer of adhesive A needs to be applied on the surface of the knitted felt with a brush, and then the next layer of knitted felt is laid. The laying speed of the subsequent knitted felt can be accelerated accordingly. The laying process of the knitted felt needs to be continuous and cannot be interrupted. , until the outermost layer of knitted felt laid on the pipe is flush with the original pipe body (the outer layer 8 of the original pipe section 5, the same below). After the adhesive A is cured and stabilized, the surface of the repaired part and the circumference of the nearby pipe body are polished and smoothed. The knitted felt is wound along the circumference of the damaged part and the nearby pipe body and wrapped tightly with a mesh cloth. The winding process must be continuous and cannot be interrupted. Finally, it is wrapped tightly with a mesh cloth. The repair can be completed when the temperature of the repaired part drops to the ambient temperature. For bamboo-wrapped composite pipes with high internal pressure, a clamp or half joint can be added to the repaired part after repair to improve the pressure resistance.

[0038] In the step A1, a line is drawn at a position extending 5-10 cm outside the edge of both sides of the damaged part, and the bevel cutting angle is controlled at 30°.

[0039] In step A3, the knitted felt is wound along the circumferential direction of the damaged part and the nearby tube body and tightly wrapped with mesh cloth. The number of knitted felt winding layers is 16, and the wrapping range of the knitted felt needs to reach at least 30 cm extending outward from the damaged part of the tube body.

[0040] The preparation method of the adhesive A comprises the following steps: preparing a resin raw material of corresponding mass, adding a promoter to the resin raw material and stirring, and adding an initiator after 4 minutes and stirring evenly.

[0041] In the adhesive A, the mass proportion of the initiator is 1%, the mass proportion of the accelerator is 45%, the resin raw material is 7501 type unsaturated resin, the accelerator is cobalt cyclohexaneate (calculated as cobalt, %) ≥ 6.0, and the initiator is methyl ethyl ketone peroxide (active oxygen ≥ 9%).

[0042] The pipe joint replacement and repair method comprises the following steps:

[0043] B1: Drain the medium in the pipeline until the inside of the pipeline is dry, find the location of large-scale damage in the pipeline, draw a line 30 cm outside the edge of the damaged area on both sides as the cutting line 4, and use bricks or earth piles to support the pipeline on the outside of the cutting line 4. Measure the length of the pipe body between the cutting lines 4 on both sides, use a cutter to cut the pipe body along the drawn position, draw a line mark 15 cm back from the cut end face of the original pipe section 5, use a cutter to bevel along the drawn position to the end face to the lining and expose the lining, avoid cutting the lining of the pipeline, use a hammer and a carpenter's push knife to completely remove the structural layer on the surface of the lining, use a utility knife to remove the residual structural layer (the structural layer is the main part of the pipe wall, in the bamboo-wrapped composite pipe, from the inside to the outside are the inner lining layer, the structural layer, and the outer protective layer, where the inner lining layer and the outer protective layer are very thin, so the thickness of the outer protective layer can be ignored) and bamboo strips at the corner (beveled area), and only keep the inner lining to obtain the inclined surface B51 on the original pipe section 5.

[0044] B2: Take a bamboo-wrapped composite pipe of the same specification as the damaged pipe, cut a pipe section of the same length as the pipe section cut off in step B1 to obtain a replacement section 6, draw a line mark 15 cm back from the cut end face of the replacement section 6, and perform the same operation as in step B1. Use a cutting machine to bevel along the marked position to the end face to the lining and expose the lining, remove all the structural layers on the surface of the lining, and obtain a bevel C61 on the replacement section 6. Align the end faces of the replacement section 6 on both sides with the corresponding end faces of the original pipe section 5 and connect them. Use an angle grinder to grind the lining at the connection between the replacement section 6 and the original pipe section 5 to make it smooth. Use a brush to evenly apply adhesive B to the joint between the replacement section 6 and the original pipe section 5. Use 3 layers of bamboo fiber felt to wrap the joint, and then use knitted felt for continuous polishing. Winding: Each time a layer of knitted felt is wound, a layer of adhesive B needs to be brushed on the surface of the knitted felt with a brush, and then the next layer of knitted felt is wound. The winding process of the knitted felt needs to be continuous and cannot be interrupted. The outermost layer needs to be wrapped with another layer of knitted felt, and the wrapping range of the knitted felt needs to reach at least 30cm on both sides of the joint. Finally, wrap it with 3 layers of mesh cloth and wrap it tightly. The thickness of the knitted felt wrapped at the joint needs to be greater than the thickness of the original pipe body, and the thickness should be the same as the wall thickness of the pipe (the thickness of the inner lining layer, structural layer, and outer protective layer added together). After the adhesive B is cured, it should be polished and smoothed. The repair can be completed when the temperature of the repaired area drops to room temperature. For bamboo-wrapped composite pipes with high internal pressure, clamps or half joints can be added to the repaired area after repair to improve the pressure resistance.

[0045] The preparation method of the adhesive B comprises the following steps: preparing a resin raw material of corresponding mass, adding an accelerator to the resin raw material and stirring, adding an initiator after 4 minutes and stirring evenly, the mass of the initiator is 1% of the mass of the resin raw material, the mass of the accelerator is 0.5% of the mass of the resin raw material, the resin raw material is 7501 type unsaturated resin, the accelerator is cobalt cyclohexaneate (calculated as cobalt, %) ≥ 6.0, and the initiator is methyl ethyl ketone peroxide (active oxygen ≥ 9%).

[0046] In the step B1, the bevel cutting angle is 30°, and the exposed lining length is 15 cm.

[0047] In step B2, the number of layers of knitted felt continuously wound is 16, and the knitted felt wound along the cutting lines 4 on both sides overlap and overlap each other, and the width of the overlap is 3 cm.

[0048] The local repair method is adopted when the damaged area of ​​the bamboo wrapped composite pipe does not exceed 25% of the pipe circumference, and the pipe segment replacement repair method is adopted when the damaged area of ​​the bamboo wrapped composite pipe exceeds 25% of the pipe circumference and cannot be solved by the local repair method.

[0049] Example 2

[0050] like Figures 1 to 7 As shown, a method for repairing a bamboo-wrapped composite pipe includes a local repair method and a pipe segment replacement repair method. The local repair method includes the following steps:

[0051] A1: Drain the medium in the pipeline until the inside of the pipeline is dry, mark the damaged part of the pipeline (damage point 1, the same below), draw a line on the outside of the edge of the damaged part, and use a cutting machine to cut obliquely along the drawn position to the pipeline lining (pipeline inner layer 7, the same below) to obtain the inclined surface A3, and avoid cutting the pipeline lining.

[0052] A2: After the cutting is completed, use a woodworking push knife and a hammer to remove the structural layer of the pipe (the outer layer of the pipe 8, the same below), and then use a utility knife to remove the remaining bamboo strips at the corners of the cut. If there are extended cracks in the lining, expand the groove to expose all the damaged parts of the lining. After the structural layer is removed, grind and clean the surface of the lining to obtain the processed groove 2.

[0053] A3: Use a brush to evenly apply adhesive A on the surface of the lining, use scissors to cut the bamboo fiber felt and knitted felt into the same shape as the processing groove 2 formed by cutting, and lay the bamboo fiber felt flat on the lining after applying adhesive A. After adhesive A solidifies, apply adhesive A on the upper surface of the bamboo fiber felt, and then use knitted felt to lay it continuously. For each layer of knitted felt, a layer of adhesive A needs to be applied on the surface of the knitted felt with a brush, and then the next layer of knitted felt is laid. The laying speed of the subsequent knitted felt can be accelerated accordingly. The laying process of the knitted felt needs to be continuous and cannot be interrupted. , until the outermost layer of knitted felt laid on the pipe is flush with the original pipe body (the outer layer 8 of the original pipe section 5, the same below). After the adhesive A is cured and stabilized, the surface of the repaired part and the circumference of the nearby pipe body are polished and smoothed. The knitted felt is wound along the circumference of the damaged part and the nearby pipe body and wrapped tightly with a mesh cloth. The winding process must be continuous and cannot be interrupted. Finally, it is wrapped tightly with a mesh cloth. The repair can be completed when the temperature of the repaired part drops to the ambient temperature. For bamboo-wrapped composite pipes with high internal pressure, a clamp or half joint can be added to the repaired part after repair to improve the pressure resistance.

[0054] In the step A1, a line is drawn at 8 cm on both sides of the outer side of the edge of the damaged part, and the bevel cutting angle is controlled at 45°.

[0055] In step A3, the knitted felt is wound along the circumferential direction of the damaged part and the nearby tube body and tightly wrapped with mesh cloth. The number of knitted felt winding layers is 16, and the wrapping range of the knitted felt needs to reach at least 30 cm extending outward from the damaged part of the tube body.

[0056] The preparation method of the adhesive A comprises the following steps: preparing a resin raw material of corresponding mass, adding a promoter to the resin raw material and stirring, and adding an initiator after 2 minutes and stirring evenly.

[0057] In the adhesive A, the mass proportion of the initiator is 0.75%, the mass proportion of the accelerator is 0.3%, the resin raw material is 7501 type unsaturated resin, the accelerator is cobalt cyclohexaneate (calculated as cobalt, %) ≥ 6.0, and the initiator is methyl ethyl ketone peroxide (active oxygen ≥ 9%).

[0058] The pipe joint replacement and repair method comprises the following steps:

[0059] B1: Drain the medium in the pipeline until the inside of the pipeline is dry, find the location where the pipeline is damaged on a large area, draw a line 40 cm outside the edge of the damaged area on both sides as the cutting line 4, and use bricks or earth piles to support the pipeline on the outside of the cutting line 4. Measure the length of the pipe body between the cutting lines 4 on both sides, use a cutter to cut the pipe body along the drawn position, draw a line mark 10 cm back from the cut end face of the original pipe section 5, use a cutter to bevel along the drawn position to the end face to the lining and expose the lining, avoid cutting the lining of the pipeline, use a hammer and a carpenter's push knife to completely remove the structural layer on the surface of the lining, use a utility knife to remove the residual structural layer (the structural layer is the main part of the pipeline wall, in the bamboo-wrapped composite pipeline, from the inside to the outside are the inner lining layer, the structural layer, and the outer protective layer, where the inner lining layer and the outer protective layer are very thin, so the thickness of the outer protective layer can be ignored) and bamboo strips at the corner (beveled area), and only keep the inner lining to obtain the inclined surface B51 on the original pipe section 5.

[0060] B2: Take a bamboo-wrapped composite pipe of the same specification as the damaged pipe, cut a pipe section of the same length as the pipe section cut off in step B1 to obtain a replacement section 6, draw a line mark 10 cm back from the cut end face of the replacement section 6, and perform the same operation as in step B1. Use a cutting machine to bevel along the marked position to the end face to the lining and expose the lining, remove all the structural layers on the surface of the lining, and obtain a bevel C61 on the replacement section 6. Align the end faces of the replacement section 6 on both sides with the corresponding end faces of the original pipe section 5 and connect them. Use an angle grinder to grind the lining at the connection between the replacement section 6 and the original pipe section 5 to make it smooth. Use a brush to evenly apply adhesive B to the seam between the replacement section 6 and the lining of the original pipe section 5. Use 2 layers of bamboo fiber felt to wrap the seam, and then use knitted felt to continuously polish it. Winding: Each time a layer of knitted felt is wound, a layer of adhesive B needs to be brushed on the surface of the knitted felt with a brush, and then the next layer of knitted felt is wound. The winding process of the knitted felt needs to be continuous and cannot be interrupted. The outermost layer needs to be wrapped with another layer of knitted felt, and the wrapping range of the knitted felt needs to reach at least 30cm on both sides of the joint. Finally, wrap it with 2 layers of mesh cloth and wrap it tightly. The thickness of the knitted felt wrapped at the joint needs to be greater than the thickness of the original pipe body, and the thickness should be the same as the wall thickness of the pipe (the thickness of the inner lining layer, structural layer, and outer protective layer added together). After the adhesive B is cured, it should be polished and smoothed. The repair can be completed when the temperature of the repaired area drops to room temperature. For bamboo-wrapped composite pipes with high internal pressure, clamps or half joints can be added to the repaired area after repair to improve the pressure resistance.

[0061] The preparation method of the adhesive B comprises the following steps: preparing a resin raw material of corresponding mass, adding an accelerator to the resin raw material and stirring, adding an initiator after 2 minutes and stirring evenly, the mass of the initiator is 1.5% of the mass of the resin raw material, the mass of the accelerator is 0.3% of the mass of the resin raw material, the resin raw material is 7501 type unsaturated resin, the accelerator is cobalt cyclohexaneate (calculated as cobalt, %) ≥ 6.0, and the initiator is methyl ethyl ketone peroxide (active oxygen ≥ 9%).

[0062] In the step B1, the bevel cutting angle is 30°, and the exposed lining length is 10 cm.

[0063] In step B2, the number of layers of knitted felt continuously wound is 16, and the knitted felt wound along the cutting lines 4 on both sides overlap and overlap each other, and the width of the overlap is 3 cm.

[0064] The local repair method is adopted when the damaged area of ​​the bamboo wrapped composite pipe does not exceed 25% of the pipe circumference, and the pipe segment replacement repair method is adopted when the damaged area of ​​the bamboo wrapped composite pipe exceeds 25% of the pipe circumference and cannot be solved by the local repair method.

[0065] The repair method of the present invention can be used to repair the bamboo-wrapped composite pipe used as a high-pressure water supply or other liquid medium pipe when it is damaged. The repair can be completed within 2-4 hours, and the pipe can continue to supply water after the repair is completed. Among them, adhesive A and adhesive B can be adjusted according to the temperature conditions on site. Before preparing adhesive A and adhesive B, they should be subjected to gel tests according to GB / T7193.6 according to the temperature conditions at the time, and then used; among them, the lower the temperature, the higher the amount of promoter added; it is strictly forbidden to directly mix the initiator and promoter during preparation; the gel time is preferably 25-45 minutes, and it must be used within 30-60 minutes after preparation; in order to prevent adhesive A and adhesive B from being cured in advance due to incomplete operation, they can be prepared and used in multiple times.

[0066] The performance indicators of the repaired part are shown in Table 1. The compressive strength of the repaired part must be at least 60MPa. According to GB / T37805-2019, the repaired pipeline is subjected to a water pressure leakage test. The pressure in the pipeline is increased to 1.5 times the normal pressure and maintained for 2 minutes. If there is no leakage at the repaired part, it is qualified.

[0067] Table 1 Performance index table of pipeline repair

[0068] performance index Ring stiffness <![CDATA[3700-4500N / m 2 ]]> Hoop tensile strength 75MPa Minimum deformation rate at yield 47％ Hoop bending modulus 7500MPa Compressive strength 60MPa Linear expansion coefficient / ℃(axial direction) <![CDATA[1.7×10 -5 ]]>

Claims

1. A method for repairing a bamboo-wrapped composite pipe. Features: It includes a local repair method and a pipe segment replacement repair method; the local repair method includes the following steps: A1: Drain the medium in the pipeline and dry the inside of the pipeline. Then mark the damaged part of the pipeline and draw a line on the outside of the edge of the damaged part. Cut obliquely along the drawn line to the inner lining of the pipeline and avoid cutting the inner lining of the pipeline. A2: After cutting, remove the structural layer of the pipe, and then remove the remaining bamboo strips at the corners of the cut. If there are extended cracks in the lining, expand the groove to expose all the damaged parts of the lining. After removing the structural layer, grind and clean the surface of the lining. A3: Apply adhesive A evenly on the surface of the inner lining, cut the bamboo fiber felt and knitted felt to the same shape as the groove formed by cutting, lay the bamboo fiber felt flat on the inner lining after applying adhesive A, apply adhesive A on the upper surface of the bamboo fiber felt after adhesive A is cured, and then use knitted felt for continuous laying. Each time a layer of knitted felt is laid, a layer of adhesive A needs to be applied on the surface of the knitted felt, and then the next layer of knitted felt is laid. The knitted felt laying process needs to be continuous and uninterrupted until the outermost layer of knitted felt laid on the pipe is flush with the original pipe body; after adhesive A is cured and stable, grind the surface of the repaired part and the circumference of the nearby pipe body; wrap the knitted felt along the circumference of the damaged part and the nearby pipe body and wrap it tightly with a mesh cloth. The winding process needs to be continuous and uninterrupted, and finally wrap it tightly with a mesh cloth. The repair can be completed when the temperature of the repaired part drops to the ambient temperature; for bamboo-wrapped composite pipes with high internal pressure, add a clamp or half joint to the repaired part after repair to improve the pressure resistance; The pipe joint replacement and repair method comprises the following steps: B1: Drain the medium in the pipeline until the inside of the pipeline is dry, find the location of the large area of ​​damage in the pipeline, draw a line 40-50 cm outside the edge of the damaged area on both sides as the cutting line (4), measure the length of the pipe body between the cutting lines (4) on both sides, cut the pipe body along the drawn line position, draw a line mark 10-20 cm back from the cut end face of the original pipe section (5), cut obliquely along the drawn line position to the end face to expose the lining, avoid cutting the lining of the pipeline, remove all the structural layers on the surface of the lining, remove the remaining structural layers and bamboo strips at the corners, and only keep the lining, and obtain the inclined surface B (51) on the original pipe section (5). B2: Take a bamboo-wrapped composite pipe of the same specification as the damaged pipe, cut a pipe section of the same length as the pipe section cut off in step B1, and obtain a replacement section (6). Draw a line 10-20 cm backward from the cut end face of the replacement section (6), cut obliquely along the marked position to the end face to the lining and expose the lining, remove all the structural layers on the surface of the lining, and obtain an inclined surface C (61) on the replacement section (6). Align the end faces of the replacement section (6) with the corresponding end faces of the original pipe section (5) in pairs and connect them. Grind the lining at the connection between the replacement section (6) and the original pipe section (5) to make it smooth. Apply adhesive B evenly to the lining joint between the replacement section (6) and the original pipe section (5), wrap 2-3 layers of bamboo fiber felt around the joint, and then Use knitted felt for continuous winding. Each time a layer of knitted felt is wound, a layer of adhesive B needs to be applied to the surface of the knitted felt before the next layer of knitted felt is wound. The winding process of the knitted felt needs to be continuous and cannot be interrupted. The outermost layer needs to be wrapped with another layer of knitted felt, and the wrapping range of the knitted felt needs to at least reach 30cm on both sides of the joint. Finally, wrap it with 2-3 layers of mesh cloth and wrap it tightly. The thickness of the knitted felt at the joint needs to be greater than the thickness of the original bamboo pipe body, and the thickness should be the same as the wall thickness of the pipe. After the adhesive B is cured, it should be polished and smoothed. The repair can be completed when the temperature of the repaired area drops to room temperature. For bamboo-wrapped composite pipes with high internal pressure, add a clamp or half joint to the repaired area after repair to improve the pressure resistance.

2. A method for repairing a bamboo-wrapped composite pipe as claimed in claim 1, Features: In the step A1, a line is drawn at a position extending 5-10 cm outside the edge of the damaged part on both sides; and the bevel cutting angle is controlled at 30-45°.

3. A method for repairing a bamboo-wrapped composite pipe as claimed in claim 1, Features: In step A3, the knitted felt is wound along the circumferential direction of the damaged part and the nearby tube body and tightly wrapped with mesh cloth. The number of knitted felt winding layers is 16, and the wrapping range of the knitted felt needs to reach at least 30 cm extending outward from the damaged part of the tube body.

4. A method for repairing a bamboo-wrapped composite pipe as claimed in claim 1, Features: The preparation method of the adhesive A comprises the following steps: preparing a resin raw material of corresponding mass, adding a promoter to the resin raw material and stirring, and adding an initiator after 2-6 minutes and stirring evenly.

5. A method for repairing a bamboo-wrapped composite pipe as claimed in claim 4, Features: In the adhesive A, the mass proportion of the initiator is 0.75-1.5%, the mass proportion of the accelerator is 0.3-0.6%, the resin raw material is 7501 type unsaturated resin, and the accelerator is cobalt salt.

6. A method for repairing a bamboo-wrapped composite pipe as claimed in claim 1, Features: The preparation method of the adhesive B comprises the following steps: preparing a resin raw material of corresponding mass, adding a promoter to the resin raw material and stirring, and adding an initiator after 2-6 minutes and stirring evenly; the mass of the initiator is 0.75-1.5% of the mass of the resin raw material, and the mass of the promoter is 0.3-0.6% of the mass of the resin raw material. The resin raw material is 7501 type unsaturated resin, and the promoter is a cobalt salt.

7. A method for repairing a bamboo-wrapped composite pipe as claimed in claim 1, Features: In the step B1, the bevel cutting angle is 30-45°, and the exposed lining length is 10-15 cm.

8. A method for repairing a bamboo-wrapped composite pipe as claimed in claim 1, Features: In the step B2, the number of continuous winding layers of the knitted felt is 16 layers, and the overlapping width between the knitted felts is 2-3 cm.

9. A method for repairing a bamboo-wrapped composite pipe as claimed in claim 1, Features: The local repair method is adopted when the damaged area of ​​the bamboo wrapped composite pipe does not exceed 25% of the pipe circumference; the pipe segment replacement repair method is adopted when the damaged area of ​​the bamboo wrapped composite pipe exceeds 25% of the pipe circumference and cannot be solved by the local repair method.

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