Composite pipe and process for its production

Abstract

The application discloses a kind of composite pipe and its preparation process, belong to composite pipe technical field, including: composite pipe body, the one end of the composite pipe body is equipped with for being connected with connecting assembly, the composite pipe body includes by inside to outside setting inner lining, structural layer, outer protective layer and anti-leakage layer, the connecting assembly includes the first connecting ring being set to the one side of composite pipe body, the outer surface of the first connecting ring is fixed with first mounting ring, the surface of first mounting ring both sides is equidistant and installed with multiple connecting springs, the outer side of both sides connecting spring one end is fixedly connected with first sealing ring, the surface of first mounting ring is annular and provided with multiple limit sliding blocks.The application can reduce the waste of raw materials during the forming of composite pipe, and can improve the mechanical properties of composite pipe on the basis of realizing the preparation and processing of composite pipe.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of composite pipes, more particularly, to a composite pipe and a preparation process thereof. BACKGROUND

[0002] Composite pipes are pipes that combine the properties of multiple materials, often to achieve better physical properties, chemical stability, or cost-effectiveness. They can be used to transport fluids such as water, oil, and gas, and are widely used in industries such as chemical, petroleum, and construction. The preparation process of composite pipes is diverse.

[0003] The existing composite pipes may have uneven resin infiltration during the preparation process, resulting in local performance degradation. During the resin injection and curing process, air bubbles and voids are easily generated, affecting the mechanical properties and sealing performance of the pipe. In addition, the interface between the resin and the fiber is not well combined, which may cause stress concentration and crack propagation. SUMMARY

[0004] 1. Technical problem to be solved

[0005] To solve the problems in the prior art, the purpose of the present application is to provide a composite pipe and a preparation process thereof. The present application can reduce the waste of raw materials during the molding of the composite pipe and improve the mechanical properties of the composite pipe.

[0006] 2. Technical solution

[0007] To solve the above problems, the present application adopts the following technical solution:

[0008] A preparation process of a composite pipe, comprising the steps of:

[0009] S1, mold preparation: clean and prepare the mold, then apply release agent on the surface of the mold;

[0010] S2, laying the inner lining layer: lay the inner lining material epoxy resin on the inner surface of the mold;

[0011] S3, laying the structure layer: lay the structure layer carbon fiber on the inner lining layer;

[0012] S4, installation of vacuum bag system: install the vacuum bag system;

[0013] S5, connecting the vacuum system: connect the vacuum pipe and install the pressure gauge;

[0014] S6, resin injection and curing: inject resin into the mold, then cure the composite pipe to ensure complete hardening of the resin;

[0015] S7, demolding and post-processing: the composite pipe mold is taken out, and then the composite pipe is post-processed to ensure that the size and appearance of the pipe meet the requirements;

[0016] S8, laying an outer protective layer and an anti-leakage layer: coating the outer protective layer and the anti-leakage layer on the outer side of the composite pipe in sequence;

[0017] S9, quality inspection: the composite pipe is tested in multiple ways and recorded;

[0018] The step S4 of installing the vacuum bag system comprises:

[0019] S401, detecting whether the vacuum bag film, the sealing tape, the flow guide net and the air-permeable felt are intact without scratches, holes or pollution;

[0020] S402, laying the flow guide net in the mold to ensure that the flow guide net covers the entire composite material layer, and laying the air-permeable felt on the flow guide net;

[0021] S403, installing the resin injection pipe on the surface of the mold and installing the vacuum extraction pipe at the other end of the mold;

[0022] S404, cutting the vacuum bag film according to the shape and size of the mold, and then laying the cut vacuum bag film on the mold to ensure that the edges of the film exceed the edges of the mold;

[0023] S405, sealing the edges of the vacuum bag film on the mold with the sealing tape, gently pressing the sealing tape with a roller, and then adding another layer of sealing tape on the sealing tape;

[0024] The step S5 of connecting the vacuum extraction system comprises:

[0025] S501, connecting one end of the cut vacuum pipe to the vacuum extraction point on the mold to ensure that the connection is sealed and has no leakage, and connecting the other end of the vacuum pipe to the air inlet of the vacuum pump to ensure that the connection is sealed and has no leakage;

[0026] S502, installing a pressure gauge on the vacuum pipe;

[0027] S503, opening the vacuum pump to start vacuum extraction, observing the pressure gauge at the same time to ensure that the vacuum degree reaches 0.08 MPa, and then detecting and checking the vacuum pipe and each connection point to check whether there is leakage, and repairing in time if there is leakage;

[0028] S504, adjusting the working parameters of the vacuum pump in real time to ensure that the vacuum degree is stable within the required range, and checking the resin injection point.

[0029] As a preferred scheme of the present application, the step S2 of laying the inner lining layer comprises:

[0030] S201, according to the inner diameter and length of the pipe, cutting the size of the inner lining material, ensuring that the material is enough to cover the entire inner surface and leave enough margin for fixing and sealing;

[0031] S202, lay the cut inner lining material on the inner surface of the mold, use the roller to help the material closely adhere to the mold surface, avoid the generation of bubbles and wrinkles;

[0032] S203, use the roller tool to gradually exclude the air under the inner lining material from one end to the other end, ensure that the inner lining layer is completely adhered to the mold surface without bubbles;

[0033] S204, use the adhesive tape to fix the edge of the inner lining material on the mold, prevent it from shifting in subsequent operations, ensure that the edge of the inner lining material is flat and free of warping, then check the flatness and adhesion of the inner lining material again, ensure that there are no bubbles and wrinkles.

[0034] As a preferred scheme of the present application, the step S3 of laying the structural layer comprises:

[0035] S301, according to the inner diameter and length of the pipe, cutting the size of the structural layer, ensuring that the material is enough to cover the entire mold surface and leave enough margin for fixing and sealing;

[0036] S302, lay the cut structural layer at 0°, 45° and 90° on the inner lining layer;

[0037] S303, after laying a layer, use the roller or scraper to exclude bubbles, ensure that the layers are tightly combined, and make the edges of the structural layer overlap to avoid gaps or weak points.

[0038] The step S6 of resin injection and curing comprises the steps of:

[0039] S601, start the vacuum pump, inject resin into the mold through the resin injection port, under the action of vacuum, the resin will be sucked into the structural layer to fill all the gaps, while monitoring the flow of the resin to ensure uniform distribution.

[0040] S602, let the resin preliminarily cure for 1-2 hours at room temperature;

[0041] S603, then put the mold together with the preform into the oven, set the temperature to 80°C for 2 hours, then to 120°C for 4 hours.

[0042] As a preferred scheme of the present application, the step S7 of demolding and post-processing comprises:

[0043] S701, cool the composite pipe to room temperature by fan;

[0044] S702, remove the air-tight sealing film and the air-permeable film covering the mold;

[0045] S703, disassemble the mold outside the composite pipe;

[0046] S704, polish the surface of the composite pipe using an electric polishing tool;

[0047] S705, polish the surface using a polishing wheel;

[0048] S706, cut and drill the composite pipe using a cutting machine and a drill machine;

[0049] As a preferred embodiment of the present application, the step S8 of laying the outer protective layer and the anti-leakage layer comprises:

[0050] S801, immerse the pipe in the pre-prepared polyurethane material, then slowly lift it up, let the excess material drip, and then dry the pipe again;

[0051] S802, immerse the dried pipe in the pre-prepared high-density polyethylene material, then slowly lift it up, and let the excess material drip.

[0052] As a preferred embodiment of the present application, the step S9 of quality inspection comprises:

[0053] S901, appearance inspection: check whether the pipe surface has defects such as cracks, bubbles, delamination, scratches and depressions;

[0054] S902, size detection: use a caliper to measure the length and diameter of the pipe, and use an ultrasonic thickness gauge to measure the wall thickness of the pipe;

[0055] S903, physical property testing, calculate the density of the pipe by weighing and volume measurement, measure the hardness of the pipe using a Shore hardness tester, test the tensile strength and elastic modulus of the pipe by a tensile testing machine, test the bending strength of the pipe by a three-point bending test, and evaluate its bending resistance;

[0056] S904, chemical property testing: place the pipe sample in a corrosion environment of salt spray test, observe its corrosion resistance, test the performance change of the pipe after contacting different chemicals, and ensure its stability in specific working environment;

[0057] S905, test the impact strength of the pipe by a falling weight impact test or a pendulum impact test, evaluate its impact resistance, test the fatigue life of the pipe under repeated load by a fatigue testing machine, ensure its long-term performance, and test the deformation of the pipe under radial pressure by a ring stiffness test, evaluate its compression resistance;

[0058] S906, non-destructive testing: use ultrasonic flaw detector to detect whether there are delamination, cavity, inclusion in the pipeline, check the internal structure of the pipeline through X-ray imaging technology, ensure its integrity, use fluorescent or colored penetrating liquid to detect the small cracks on the surface of the pipeline;

[0059] S907, air tightness test: check the sealing performance of the pipeline through water pressure test, ensure that it does not leak under working pressure;

[0060] S908, environmental adaptability test, place the pipeline in high temperature environment, observe its performance change under high temperature condition, place the pipeline in low temperature environment, test its impact strength and toughness under low temperature condition, expose the pipeline to ultraviolet light, evaluate its anti-ultraviolet aging performance;

[0061] S909, record and report: record the data and results of each test in detail, compile quality inspection report, summarize test results, evaluate whether the product quality meets the standard and design requirements.

[0062] A composite pipeline, comprising: a composite pipeline body, one end of the composite pipeline body is provided with a connecting assembly for connection, the composite pipeline body comprises an inner lining layer, a structural layer, an outer protective layer and a leakage prevention layer arranged from inside to outside;

[0063] The connecting assembly comprises a first connecting ring arranged on one side of the composite pipeline body, a first mounting ring is fixedly arranged on the outer surface of the first connecting ring, a plurality of connecting springs are equidistantly arranged on the surfaces on both sides of the first mounting ring, a first sealing ring is fixedly connected to the outer side of each of the connecting springs on both sides, a plurality of limiting sliding blocks are arranged in a ring shape on the surface of the first mounting ring, two first connecting pieces are arranged on the surface of the first connecting ring, a limiting sliding groove corresponding to the limiting sliding blocks is formed in the surface of the first connecting piece, a second connecting ring is arranged on both sides of the first connecting ring, a second connecting piece is arranged on the outer side of the second connecting ring, and the first connecting ring is fixed to one end of the composite pipeline body and the surface of the first connecting ring through the two second connecting pieces, a tooth-shaped sealing ring and a second sealing ring are arranged on the inner wall of the second connecting piece and located on both sides of the second connecting ring, mounting seats are fixedly arranged on both sides of the top of the second connecting piece, and the two mounting seats are adjusted through fixing bolts.

[0064] As a preferred scheme of the present application, the material of the inner lining layer is epoxy resin, the thickness of the inner lining layer is 0.1mm-1.0mm, the material of the structural layer is carbon fiber, the thickness of the structural layer is 10mm-20mm, the material of the outer protective layer is polyurethane, the thickness of the outer protective layer is 0.5mm-2mm, the material of the leakage prevention layer is high-density polyethylene, and the thickness of the leakage prevention layer is 0.1mm-0.5mm.

[0065] 3. Beneficial effects

[0066] Compared with the prior art, the present application has the advantages of:

[0067] The present application can significantly reduce raw material waste, simplify the operation process, reduce labor costs, effectively improve the mechanical properties of the composite material, including strength, stiffness and durability, and the resin is usually an environmentally friendly material with low volatile organic compound content, which helps to reduce the impact on the environment, and the composite pipe body can be suitable for various types of structural layers and resin systems, and can flexibly respond to the needs of different application scenarios, easy to realize automation, further improve the production efficiency and product consistency. BRIEF DESCRIPTION OF DRAWINGS

[0068] Figure 1 is a first perspective view of a composite pipe according to the present application;

[0069] Figure 2 is an exploded view of a connecting assembly in a composite pipe according to the present application;

[0070] Figure 3 is a first partial exploded view of a connecting assembly in a composite pipe according to the present application;

[0071] Figure 4 is a second partial exploded view of a connecting assembly in a composite pipe according to the present application.

[0072] REFERENCE NUMERALS IN DRAWINGS

[0073] 1, composite pipe body; 2, connecting assembly; 201, first connecting ring; 202, first mounting ring; 203, connecting spring; 204, first sealing ring; 205, limiting sliding block; 206, first connecting piece; 207, limiting sliding groove; 208, second connecting ring; 209, second connecting piece; 210, toothed sealing ring; 211, second sealing ring; 212, mounting seat; 213, fixing bolt. DETAILED DESCRIPTION

[0074] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor fall within the scope of protection of the present application.

[0075] Embodiment:

[0076] A preparation process of a composite pipe, comprising the steps of:

[0077] S1, mold preparation: clean and prepare the mold, ensure the smooth surface of the mold and no impurities, then coat the mold surface with release agent for subsequent demolding;

[0078] S2, lay the inner liner: lay the inner liner material epoxy resin on the inner surface of the mold, ensure that the inner liner is uniform, flat and bubble-free;

[0079] S3, lay the structure layer: lay the structure layer carbon fiber on the inner liner, ensure that there is no gap between the fiber layers and arrange neatly;

[0080] S4, install the vacuum bag system: install the vacuum bag system;

[0081] S5, connect the vacuum system: connect the vacuum pipe and install the pressure gauge;

[0082] S6, resin injection and curing: inject resin into the mold, then cure the composite pipe to ensure complete hardening of the resin;

[0083] S7, demolding and post-processing: remove the composite pipe from the mold, then post-process the composite pipe to ensure that the pipe size and appearance meet the requirements;

[0084] S8, lay the outer protective layer and the anti-leakage layer: coat the outer protective layer and the anti-leakage layer on the outside of the composite pipe in turn, ensure that the outer protective layer is uniform and defect-free;

[0085] S9, quality inspection: test the composite pipe and record the results;

[0086] Specifically, the step S4 of installing the vacuum bag system comprises:

[0087] S401, check the vacuum bag film, sealing tape, flow guide net and air-permeable felt for any damage, scratches, holes or contamination;

[0088] S402, lay the flow guide net inside the mold, ensure that the flow guide net covers the entire composite material layer, which helps the resin to be evenly distributed, lay the air-permeable felt on the flow guide net to further improve the flowability and air exhaust effect of the resin;

[0089] S403, install the resin injection pipe on the surface of the mold to ensure that the resin can flow smoothly into the mold, install the vacuum pipe at the other end of the mold to ensure that the vacuum system can effectively extract air;

[0090] S404, cut the vacuum bag film according to the shape and size of the mold, then lay the cut vacuum bag film on the mold, ensure that the edges of the film exceed the edges of the mold for easy sealing;

[0091] S405, seal the edge of the vacuum bag film on the mold using sealing tape, press the sealing tape gently with a roller to ensure good sealing, then add another layer of sealing tape on the sealing tape to increase the sealing effect;

[0092] The step S5 connecting the vacuum system comprises:

[0093] S501, connect one end of the cut vacuum pipe to the vacuum point on the mold, ensure that the connection is sealed well without leakage, and connect the other end of the vacuum pipe to the air inlet of the vacuum pump, ensure that the connection is sealed well without leakage;

[0094] S502, install a pressure gauge on the vacuum pipe to monitor the vacuum degree in real time;

[0095] S503, turn on the vacuum pump to start vacuumizing, and observe the pressure gauge at the same time to ensure that the vacuum degree reaches 0.08 MPa, then carefully check the vacuum pipe and each connection point to check if there is leakage, if there is leakage, repair in time;

[0096] S504, adjust the working parameters of the vacuum pump in real time to ensure that the vacuum degree is stable within the required range, and check the resin injection point to ensure that the resin injection point is sealed well to prevent air from entering.

[0097] Specifically, the step S2 of laying the inner lining layer comprises:

[0098] S201, according to the inner diameter and length of the pipeline, cut the size of the inner lining material to ensure that the material is enough to cover the entire inner surface and has enough excess to facilitate fixation and sealing;

[0099] S202, lay the cut inner lining material on the inner surface of the mold, use a roller to help the material closely adhere to the mold surface to avoid air bubbles and wrinkles;

[0100] S203, use a roller tool to gradually remove the air under the inner lining material from one end to the other end to ensure that the inner lining layer completely adheres to the mold surface without air bubbles;

[0101] S204, use adhesive tape to fix the edge of the inner lining material on the mold to prevent it from shifting during subsequent operations, ensure that the edge of the inner lining material is flat and free of warping, then check the flatness and adhesion of the inner lining material again to ensure that there are no air bubbles, wrinkles.

[0102] Specifically, the step S3 of laying the structure layer comprises:

[0103] S301, according to the inner diameter and length of the pipeline, cut the size of the structure layer and leave enough excess to facilitate fixation and sealing;

[0104] S302, install the cut structure layer on the inner liner layer at 0°, 45° and 90°;

[0105] S303, after laying a layer, use a roller or a scraper to remove bubbles, ensure that the layers are tightly combined, and make the edges of the structure layer overlap, ensure that the edges of the layers are properly overlapped, and avoid gaps or weak points.

[0106] Specifically, the step S6 resin injection and curing includes the steps of:

[0107] S601, start the vacuum pump, inject resin into the mold through the resin injection port, and under the action of vacuum, the resin will be sucked into the structure layer to fill all the gaps, while monitoring the flow of the resin to ensure uniform distribution of the resin.

[0108] S602, let the resin cure at room temperature for 1-2 hours;

[0109] S603, then put the mold together with the preform into an oven, set the temperature to 80°C for 2 hours, and then at 120°C for 4 hours.

[0110] Specifically, the step S7 demolding and post-processing includes:

[0111] S701, cool the composite pipe to room temperature by fan;

[0112] S702, remove the air-tight sealing film and the air-permeable film covering the outside of the mold to avoid damage to the composite pipe;

[0113] S703, disassemble the mold outside the composite pipe;

[0114] S704, use an electric polishing tool to polish the surface of the composite pipe to remove burrs and uneven parts and make the surface smooth;

[0115] S705, use a polishing wheel to polish the surface to obtain a higher quality surface finish;

[0116] S706, use special tools for cutting and drilling machines to cut and drill the composite pipe.

[0117] Specifically, the step S8 of laying the outer protective layer and the anti-leakage layer includes:

[0118] S801, immerse the pipe in the pre-prepared polyurethane material, then slowly lift it, let the excess material drip, and then dry the pipe again;

[0119] S802, immerse the dried pipe in the pre-prepared high-density polyethylene material, then slowly lift it, and let the excess material drip.

[0120] Specifically, the step S9 quality inspection includes:

[0121] S901, appearance inspection: check whether the pipe surface has defects such as cracks, bubbles, delamination, scratches and depressions;

[0122] S902, size detection: use calipers to measure the length and diameter of the pipe, ensure that it meets the design requirements, use ultrasonic thickness gauge to measure the wall thickness of the pipe, ensure that the thickness is uniform and within the allowable range;

[0123] S903, physical property testing, calculate the density of the pipe by weighing and volume measurement, ensure that it meets the material standard, use the Shore hardness tester to measure the hardness of the pipe, ensure that it meets the design requirements, test the tensile strength and elastic modulus of the pipe by the tensile testing machine, ensure that its mechanical properties meet the standards, test the bending strength of the pipe by the three-point bending test, evaluate its bending resistance;

[0124] S904, chemical property testing: place the pipe sample in the corrosion environment of salt spray test, observe its corrosion resistance, test the performance change of the pipe after contacting different chemicals, ensure its stability in specific working environment;

[0125] S905, test the impact strength of the pipe by drop hammer impact test or pendulum impact test, evaluate its impact resistance, test the fatigue life of the pipe under repeated load by the fatigue testing machine, ensure its long-term performance, test the deformation of the pipe under radial pressure by the ring stiffness test, evaluate its compression resistance;

[0126] S906, non-destructive testing: use ultrasonic flaw detector to detect whether there are delamination, cavity, inclusion inside the pipe, check the internal structure of the pipe by X-ray imaging technology, ensure its integrity, use fluorescent or colored penetrating liquid to detect the tiny cracks on the surface of the pipe;

[0127] S907, air tightness test: check the sealing performance of the pipe by water pressure test, ensure that it does not leak under working pressure;

[0128] S908, environmental adaptability test, place the pipe in high temperature environment, observe its performance change under high temperature condition, place the pipe in low temperature environment, test its impact strength and toughness under low temperature condition, expose the pipe to ultraviolet light, evaluate its anti-ultraviolet aging performance;

[0129] S909, record and report: record the data and results of each test in detail, prepare the quality inspection report, summarize the test results, evaluate whether the product quality meets the standard and design requirements.

[0130] Please refer to Figures 1-4The utility model provides a kind of composite pipe, comprising: composite pipe body 1, the one end of composite pipe body 1 is equipped with the connecting assembly 2 for being connected, and composite pipe body 1 includes inner lining layer, structural layer, outer protective layer and anti-leakage layer arranged from inside to outside;

[0131] Connecting assembly 2 includes the first connecting ring 201 arranged in one side of composite pipe body 1, the outer surface of first connecting ring 201 is fixed with the first mounting ring 202, a plurality of connecting springs 203 are equidistantly mounted on the surface of both sides of first mounting ring 202, the outer side of both sides connecting spring 203 is fixedly connected with the first sealing ring 204, a plurality of limiting sliding blocks 205 are arranged in annular on the surface of first mounting ring 202, the surface of first connecting ring 201 is equipped with two first connecting pieces 206, the surface of first connecting piece 206 is provided with limiting sliding groove 207 adapted to limiting sliding block 205, both sides of first connecting ring 201 are equipped with second connecting ring 208, the outer side of second connecting ring 208 is equipped with second connecting piece 209, and first connecting ring 201 is fixed to one end of composite pipe body 1 and the surface of first connecting ring 201 through two second connecting pieces 209, the inner wall of second connecting piece 209 and located at both sides of second connecting ring 208 are provided with toothed sealing ring 210 and second sealing ring 211, and both sides of the top of second connecting piece 209 are fixed with mounting seat 212, and two mounting seats 212 are adjusted by fixed bolt 213.

[0132] In the specific embodiments of the present application, by using multiple steps in cooperation, the waste of raw materials can be significantly reduced, the operation process is simplified, the labor cost is reduced, the mechanical properties of the composite material, including strength, stiffness and durability, can be effectively improved, the resin is usually an environmentally friendly material with low volatile organic compound content, which helps to reduce the impact on the environment, and the composite pipe body 1 can be suitable for various types of structural layers and resin systems, can flexibly respond to the needs of different application scenarios, is easy to realize automation, and further improves the production efficiency and product consistency.

[0133] Specifically, the material of the inner lining layer is epoxy resin, and the thickness of the inner lining layer is 0.1mm-1.0mm, which provides good chemical stability and smooth inner surface for the composite pipe body 1, prevents the erosion of the fluid to the pipe material, and reduces the frictional resistance when the fluid flows;

[0134] The material of the structural layer is carbon fiber, and the thickness of the structural layer is 10mm-20mm, which bears the main mechanical strength of the composite pipe body 1, ensures that the pipe can withstand internal and external pressure, impact and bending load, etc.

[0135] The material of the outer protective layer is polyurethane, and the thickness of the outer protective layer is 0.5mm-2mm, which provides additional physical and chemical protection, prevents the erosion of the pipeline by the external environment, and improves the weather resistance and ultraviolet resistance of the composite pipeline body 1;

[0136] The material of the anti-leakage layer is high-density polyethylene, and the thickness of the anti-leakage layer is 0.1mm-0.5mm, which further improves the sealing and anti-leakage performance of the pipeline, especially when conveying harmful substances or high-pressure fluids.

[0137] The above is only a preferred specific embodiment of the present application, but the protection scope of the present application is not limited to this. Any person skilled in the art can make equivalent replacements or changes within the technical range disclosed by the present application according to the technical solution and improvement concept of the present application, which should be covered within the protection scope of the present application.

Claims

1. A process for the production of a composite pipe, characterized in that, The method comprises the steps of: S1, mold preparation: clean and prepare the mold, then coat the mold surface with a release agent; S2, laying the inner lining layer: lay the inner lining material epoxy resin on the inner surface of the mold; S3, laying the structure layer: lay the structure layer carbon fiber on the inner lining layer; S4, installing the vacuum bag system: install the vacuum bag system; S5, connecting the vacuum system: connect the vacuum pipe and install the pressure gauge; S6, resin injection and curing: inject resin into the mold, then cure the composite pipe to ensure that the resin is completely hardened; S7, demolding and post-processing: remove the composite pipe from the mold, then post-process the composite pipe to ensure that the pipe size and appearance meet the requirements; S8, laying the outer protective layer and the anti-leakage layer: coating the outer protective layer and the anti-leakage layer on the outside of the composite pipe in turn; S9, quality inspection: test the composite pipe in multiple ways and record the results; The step S4 of installing the vacuum bag system comprises: S401, check the vacuum bag film, sealing tape, flow guide net and air permeable felt for any damage, scratches, holes or contamination; S402, lay the flow guide net inside the mold, ensuring that the flow guide net covers the entire composite material layer, and lay the air permeable felt on the flow guide net; S403, install the resin injection pipe on the surface of the mold, and install the vacuum pipe on the other end of the mold; S404, cut the vacuum bag film according to the shape and size of the mold, then lay the cut vacuum bag film on the mold, ensuring that the edges of the film exceed the edges of the mold; S405, use the sealing tape to seal the edges of the vacuum bag film on the mold, gently press the sealing tape with a roller, then add another layer of sealing tape on the sealing tape; The step S5 of connecting the vacuum system comprises: S501, connect one end of the cut vacuum pipe to the vacuum point on the mold, ensuring that the connection is sealed and leak-free, and connect the other end of the vacuum pipe to the air inlet of the vacuum pump, ensuring that the connection is sealed and leak-free; S502, install the pressure gauge on the vacuum pipe; S503, turn on the vacuum pump and start the vacuum, while observing the pressure gauge to ensure that the vacuum degree reaches 0.08 MPa, then carefully check the vacuum pipe and each connection point for any leaks, and repair them in a timely manner if there are any leaks; S504, adjust the working parameters of the vacuum pump in real time to ensure that the vacuum degree is stable within the required range, and check the resin injection point; The step S6 of resin injection and curing comprises the steps of: S601, start the vacuum pump and inject resin into the mold through the resin injection port, under the action of vacuum, the resin will be sucked into the structure layer to fill all the gaps, while monitoring the flow of the resin to ensure uniform distribution; S602, let the resin cure at room temperature for 1-2 hours; S603, then put the mold together with the preform into the oven, set the temperature to 80°C for 2 hours, then to 120°C for 4 hours.

2. A process for the production of a composite pipe according to claim 1, characterized in that, The step S2 of laying the inner lining layer comprises: S201, according to the inner diameter and length of the pipe, cut the inner lining material to the appropriate size, ensuring that the material is sufficient to cover the entire inner surface and has enough excess to facilitate fixation and sealing; S202, lay the cut inner liner material on the inner surface of the mold, use the roller to help the material tightly adhere to the mold surface, avoid the generation of bubbles and wrinkles; S203, use the roller tool to gradually exclude the air under the inner liner material from one end to the other end, ensure that the inner liner layer is completely adhered to the surface of the mold without bubbles; S204, use adhesive tape to fix the edges of the inner liner material on the mold, prevent it from shifting in subsequent operations, ensure that the edges of the inner liner material are flat and free of warping, then check the flatness and adhesion of the inner liner material again, ensure that there are no bubbles, wrinkles.

3. A process for the production of a composite pipe according to claim 2, characterized in that, The step S3 of laying the structural layer comprises: S301, according to the inner diameter and length of the pipeline, cut the structural layer size to ensure that the material is enough to cover the entire mold surface and has enough excess to facilitate fixation and sealing; S302, lay the cut structural layer at 0°, 45° and 90° on the inner liner layer; S303, after laying a layer, use the roller or scraper to remove bubbles, ensure that the layers are tightly combined, and make the edges of the structural layer overlap to avoid gaps or weak points.

4. The process for making a composite pipe according to claim 3, wherein, The step S7 of demolding and post-processing comprises: S701, cool the composite pipeline to room temperature by fan; S702, remove the air impermeable sealing film and the air permeable film covering the outside of the mold; S703, disassemble the mold on the outside of the composite pipeline; S704, use an electric polishing tool to polish the surface of the composite pipeline; S705, use a polishing wheel to polish the surface; S706, use special tools for cutting and drilling machines to cut and drill the composite pipeline.

5. A process for the production of a composite pipe according to claim 4, characterized in that, The step S8 of laying the outer protective layer and the anti-leakage layer comprises: S801, immerse the pipeline in the pre-prepared polyurethane material, then slowly lift it up, let the excess material drip, then dry the pipeline again; S802, immerse the dried pipeline in the pre-prepared high-density polyethylene material, then slowly lift it up, let the excess material drip.

6. A process for the production of a composite pipe according to claim 5, characterized in that, The step S9 of quality inspection comprises: S901, appearance inspection: check whether there are cracks, bubbles, delamination, scratches and indentation defects on the surface of the pipeline; S902, size detection: use a caliper to measure the length and diameter of the pipeline, and use an ultrasonic thickness gauge to measure the wall thickness of the pipeline; S903, physical property testing, calculate the density of the pipeline by weighing and volume measurement, measure the hardness of the pipeline using a Shore hardness tester, test the tensile strength and elastic modulus of the pipeline by a tensile testing machine, test the bending strength of the pipeline by a three-point bending test to evaluate its bending resistance; S904, chemical property testing: place the pipeline sample in a corrosion environment of salt spray test, observe its corrosion resistance, test the performance change of the pipeline after contacting different chemicals, ensure its stability in specific working environment; S905, test the impact strength of the pipeline by drop hammer impact test or pendulum impact test to evaluate its impact resistance, test the fatigue life of the pipeline under repeated load by a fatigue testing machine to ensure its long-term performance, test the deformation of the pipeline under radial pressure by ring stiffness test to evaluate its compression resistance; S906, non-destructive testing: use ultrasonic flaw detector to detect whether there are delamination, cavity, inclusion in the pipeline, check the internal structure of the pipeline through X-ray imaging technology to ensure its integrity, use fluorescent or colored penetrating liquid to detect the small cracks on the surface of the pipeline; S907, air tightness test: check the sealing performance of the pipeline through water pressure test to ensure that it does not leak under working pressure; S908, environmental adaptability test, place the pipeline in high temperature environment, observe its performance change under high temperature condition, place the pipeline in low temperature environment, test its impact strength and toughness under low temperature condition, expose the pipeline to ultraviolet light, evaluate its anti-ultraviolet aging performance; S909, record and report: record the data and results of each test in detail, prepare quality inspection report, summarize test results, evaluate whether the product quality meets the standard and design requirements.

7. A composite pipe for use in the process of claim 1, wherein It includes: The composite pipeline body (1) is provided with a connecting assembly (2) at one end for connection, and the composite pipeline body (1) comprises an inner lining layer, a structural layer, an outer protective layer and a leakage prevention layer arranged from inside to outside; The connecting assembly (2) comprises a first connecting ring (201) arranged on one side of the composite pipeline body (1), a first mounting ring (202) fixed to the outer surface of the first connecting ring (201), a plurality of connecting springs (203) equidistantly mounted on the surfaces on both sides of the first mounting ring (202), a first sealing ring (204) fixedly connected to one end of the outer side of each connecting spring (203), a plurality of limiting sliding blocks (205) arranged in a ring shape on the surface of the first mounting ring (202), two first connecting pieces (206) arranged on the surface of the first connecting ring (201), a limiting sliding groove (207) corresponding to the limiting sliding block (205) arranged on the surface of the first connecting piece (206), a second connecting ring (208) arranged on both sides of the first connecting ring (201), a second connecting piece (209) arranged on the outer side of the second connecting ring (208), and the first connecting ring (201) is fixed to one end of the composite pipeline body (1) and the surface of the first connecting ring (201) through the two second connecting pieces (209), a tooth-shaped sealing ring (210) and a second sealing ring (211) arranged on the inner wall of the second connecting piece (209) and located on both sides of the second connecting ring (208), and a mounting seat (212) fixed to the top of both sides of the second connecting piece (209), and the two mounting seats (212) are adjusted by the fixing bolts (213).

8. A composite pipe according to claim 7, wherein The material of the inner lining layer is epoxy resin, the thickness of the inner lining layer is 0.1mm-1.0mm, the material of the structural layer is carbon fiber, the thickness of the structural layer is 10mm-20mm, the material of the outer protective layer is polyurethane, the thickness of the outer protective layer is 0.5mm-2mm, the material of the leakage prevention layer is high-density polyethylene, and the thickness of the leakage prevention layer is 0.1mm-0.5mm.

Images