Long fiber yarn and continuous fiber band combined reinforced plastic high-pressure-resistant composite pipe structure as well as production equipment and preparation method of long fiber yarn and continuous fiber band combined reinforced plastic high-pressure-resistant composite pipe structure

Abstract

The invention discloses a long cellosilk and continuous fiber band combined reinforced plastic high-pressure-resistant composite pipe structure and production equipment and a preparation method thereof, and relates to the field of composite pipes, and the long cellosilk and continuous fiber band combined reinforced plastic high-pressure-resistant composite pipe structure comprises a gas conveying pipe and a liquid conveying pipe; the structural section layer of the gas conveying pipe comprises a first plastic inner layer, a first bonding layer, a blocking layer, a second bonding layer, a first continuous fiber band composite layer, a first long fiber yarn composite layer and a first plastic outer layer which are sequentially welded from inside to outside. According to the long fiber yarn and continuous fiber band combined reinforced plastic high-pressure-resistant composite pipe structure and the production equipment and the preparation method thereof, long glass fiber composite plastic is added to the secondary outer layer, so that the overall reinforced fiber content is higher, the overall bearing capacity of the composite pipe is remarkably improved, the thicknesses of the inner layer and the outer layer of the plastic do not need to be excessively increased, and the manufacturing cost is reduced; meanwhile, the long glass fiber composite plastic is of a three-dimensional reinforced structure and can absorb part of energy before the core layer, continuous fibers of the core layer are protected, and the overall impact strength and toughness are improved.

Description

Technical Field

[0001] This invention relates to composite pipe technology, specifically to a high-pressure resistant composite pipe structure reinforced by a combination of long fiber filaments and continuous fiber tape, as well as its production equipment and preparation method. Background Technology

[0002] In the field of pipeline engineering, continuous fiber reinforced plastic composite pipes have been widely used in many industries such as water supply, industry, and chemical industry due to their high pressure resistance and low cost. However, with the continuous expansion of application scenarios and the increasing requirements for use, existing continuous fiber reinforced plastic composite pipes have exposed many problems that urgently need to be solved.

[0003] In existing technologies, continuous fiber reinforced plastic composite pipes without added long glass fibers use a coating process for the outer plastic layer. Due to the large difference in shrinkage stress between the coated plastic outer layer and the continuous fiber layer at the bonding surface, the bond between the two is not strong, and delamination between the plastic outer layer and the continuous fiber layer is likely to occur. Delamination not only allows water to enter between the layers at the ends, causing rupture under pressure and leading to failure of the composite pipe, but also leaves the coated plastic outer layer and the continuous fiber layer in a semi-separated state. After the composite pipe ends are connected to the fittings, the strength of the plastic outer layer is insufficient to withstand axial tension, making it prone to failure. Therefore, this paper proposes a high-pressure resistant plastic composite pipe structure reinforced with a combination of long fiber filaments and continuous fiber tape, as well as its production equipment and preparation method. Summary of the Invention

[0004] The purpose of this invention is to provide a high-pressure resistant composite pipe structure for plastic reinforced with long fiber filaments and continuous fiber tape, as well as its production equipment and preparation method, to solve the problem in the prior art where continuous fiber reinforced plastic composite pipes without the addition of long glass fibers use a coating production process. Due to the large difference in shrinkage stress between the coated plastic outer layer and the continuous fiber layer at the bonding surface, the bonding between the two is not reliable, and delamination between the plastic outer layer and the continuous fiber layer is likely to occur.

[0005] To achieve the above objectives, the present invention provides the following technical solution: a high-pressure resistant composite pipe structure for plastics reinforced with a combination of long fiber filaments and continuous fiber tape, comprising a gas conveying pipe and a liquid conveying pipe;

[0006] The structural cross-section of the gas delivery pipe, from the inside out, includes a first plastic inner layer, a first adhesive layer, a barrier layer, a second adhesive layer, a first continuous fiber tape composite layer, a first long fiber composite layer, and a first plastic outer layer, which are welded together sequentially.

[0007] The structural cross-section of the liquid conveying pipe, from the inside out, consists of a second plastic inner layer, a second continuous fiber tape composite layer, a second long fiber composite layer, and a second plastic outer layer, which are sequentially fused together.

[0008] Furthermore, both the gas delivery pipe and the liquid delivery pipe are equipped with optical fiber cables inside their structural cross-sectional layers for tracking and testing pipe leakage, with the two optical fiber cables respectively located in the first long fiber composite layer and the second long fiber composite layer.

[0009] Furthermore, the first continuous fiber tape composite layer and the second continuous fiber tape composite layer include a bidirectional double-layer tape with unidirectional single-layer tape and unidirectional single-layer tape cross-laminated and fused together, wherein the fiber content of the bidirectional double-layer tape with unidirectional single-layer tape and unidirectional single-layer tape cross-laminated and fused together is 30%-70%; the fiber content of the first long fiber filament composite layer and the second long fiber filament composite layer is 10%-50%, and the fiber length of the first long fiber filament composite layer and the second long fiber filament composite layer is 2-30mm.

[0010] Furthermore, the first adhesive layer is fused to the first plastic inner layer and the barrier layer respectively, the second adhesive layer is fused to the barrier layer and the first continuous fiber composite layer respectively, the first long fiber composite layer is fused to the first continuous fiber tape composite layer and the first plastic outer layer respectively, the second continuous fiber tape composite layer is connected to the second plastic inner layer and the second long fiber composite layer respectively, and the second long fiber composite layer is connected to the second continuous fiber tape composite layer and the second plastic outer layer respectively. The barrier tube layer designed to prevent gas permeation and escape is mainly composed of EVOH barrier material. The first plastic inner layer, the first adhesive layer, the barrier layer, and the second adhesive layer together form the barrier structure.

[0011] Furthermore, the ends of the gas conveying pipe and the liquid conveying pipe are respectively sealed by a first plastic inner layer and a second plastic inner layer. The first and second plastic inner layers are processed to form a heat-fused or electrofusion connection fitting for full network connectivity. This connection method can meet the requirements of preventing gas escape at the pipe end interface and simultaneously preventing gas escape throughout the network. On the other hand, it can withstand high pressure or ultra-high pressure requirements in sync with the composite pipe. The fibers include glass fiber, basalt fiber, carbon fiber, composite fibers of glass fiber and basalt fiber, composite fibers of glass fiber and carbon fiber, and composite fibers of basalt fiber and carbon fiber. The plastics include polypropylene, polyethylene, polybutene, polyvinyl chloride, ultra-high molecular weight polyethylene, nylon, and ABS. The conveying gas of the gas conveying pipe includes hydrogen, fuel gas, ammonia, carbon dioxide, and mixtures of hydrogen and fuel gas and mixtures of hydrogen and ammonia.

[0012] Furthermore, one end of the gas conveying pipe and the liquid conveying pipe is provided with a composite pipe sealing joint. The composite pipe sealing joint consists of a plastic sealing section and a composite pipe section used for rounding, sizing, and fusion of the composite pipe. The connection method uses long fiber reinforced composite pipe fittings as sleeve socket connectors, and the high-pressure resistant composite pipe sealing ends are connected to form a pipeline system by electrofusion or hot fusion.

[0013] The preparation method of the plastic sealing section is as follows: first, the continuous fiber core layer with a fiber removal machine is removed to a depth of 1-10mm. The remaining plastic layers inside and outside the tube end are heated in an oven and then extruded by an end mold to form a closed plastic section.

[0014] The method for preparing the composite pipe section is as follows: After the end of the continuous fiber-wound reinforced plastic composite pipe is heated to a molten state in an oven, under the combined action of the inner and outer molds, the inner mold is inserted into the inner wall of the composite pipe end and expanded to round the composite pipe end. At the same time, the outer mold is inserted into and wraps around the outer wall of the composite pipe end and sizing the composite pipe end with the standard outer diameter circumference. Under the combined action of the expansion force of the inner mold and the extrusion force of the outer mold, the inner and outer plastic layers and the continuous fiber core layer of the continuous fiber-wound reinforced plastic composite pipe end are fused together and combined with the plastic sealing section to form a high-pressure resistant composite pipe sealing joint.

[0015] A production equipment for a high-pressure resistant plastic composite pipe structure reinforced with a combination of long fiber filaments and continuous fiber tapes includes the following apparatus:

[0016] Multiple inner tube extruders are connected to an inner tube multi-layer co-extrusion composite die for producing a first plastic inner layer, a first adhesive layer, a barrier layer, a first adhesive layer, and a second plastic inner layer. Through the multi-layer co-extrusion composite die, the synchronous extrusion and compounding of each layer of material can be achieved, improving production efficiency and product quality.

[0017] The inner tube vacuum sizing cooling water tank is located at the front end of the inner tube multi-layer co-extrusion composite mold and is used to sizing the extruded inner tube to ensure the dimensional accuracy of the inner tube.

[0018] The inner tube shaping cooling water tank is located at the front end of the vacuum sizing cooling water tank and is used to shape the inner tube so that the inner tube maintains a stable shape during the cooling process.

[0019] The first traction machine is located at the front end of the inner tube shaping cooling water tank. It is used to pull the inner tube so that it moves forward at a certain speed to ensure the continuity of production.

[0020] Multiple sets of continuous fiber winding discs are used to produce the first continuous fiber tape composite layer and the second continuous fiber tape composite layer, and are set at the front end of the first traction machine; through the continuous fiber winding discs, fibers can be evenly wound on the inner tube to form a continuous fiber tape composite layer;

[0021] A fiber optic laying machine is installed at the front end of a continuous fiber winding reel and is used to lay fiber optic cables.

[0022] The outer tube extruder is equipped with an outer tube composite co-extrusion die, which is located at the front end of the optical fiber laying machine. It is used to produce the first long fiber composite layer, the first plastic outer layer, the second long fiber composite layer, and the second plastic outer layer. The outer tube composite co-extrusion die can realize the synchronous extrusion and composite of the materials of each layer of the outer tube.

[0023] The air cooler is located at the front end of the outer tube composite co-extrusion die and is used to cool the extruded first and second plastic outer layers, accelerate the cooling and solidification of the plastic, and improve production efficiency.

[0024] The composite pipe integral shaping cooling water tank is set at the front end of the air cooler. It is used to shape the composite pipe as a whole, ensuring that the layers of the composite pipe are tightly bonded and the dimensions are stable.

[0025] The second traction machine is located at the front end of the composite pipe shaping cooling water tank. It is used to pull the composite pipe forward at a certain speed to ensure the continuity of production.

[0026] The marking machine, located at the front end of the second traction machine, is used to mark the composite pipes to facilitate product identification and management.

[0027] The cutting machine, located at the front end of the marking machine, is used to cut composite tubes of fixed length to meet the requirements of different lengths.

[0028] The receiving platform, located at the front of the cutting machine, is used to collect the cut composite pipes for subsequent packaging and transportation.

[0029] A method for preparing a high-pressure resistant plastic composite pipe structure reinforced with a combination of long fiber filaments and continuous fiber tape includes the following steps:

[0030] Step 1: Load the materials of the first plastic inner layer, the first adhesive layer, the barrier layer, the second adhesive layer, and the second plastic inner layer into the corresponding inner tube extruder hoppers respectively;

[0031] Step 2: Load the first continuous fiber tape composite layer onto the winding machine disc; then load the first long fiber composite layer, the first plastic outer layer, the second long fiber composite layer, and the second plastic outer layer into the corresponding multiple outer tube extruder hoppers respectively;

[0032] Step 3: Start multiple inner tube extruders and their connected composite molds to extrude the inner tube melt, which consists of a first plastic inner layer, a first adhesive layer, a barrier layer, and a second adhesive layer.

[0033] Step 4: Start the first traction machine. Driven by the traction pipe, the inner tube melt is pulled into the inner tube vacuum sizing cooling water tank.

[0034] Step 5: Open the inner tube vacuum sizing cooling water tank to sizing the inner tube; open the inner tube shaping cooling water tank to shape the inner tube; open multiple sets of continuous fiber winding discs to produce the first continuous fiber tape composite layer and the second continuous fiber tape composite layer; open the fiber optic cabling machine to lay the fiber optic cable; open multiple outer tube extruders and their connected outer tube composite co-extrusion dies to produce the first long fiber filament composite layer, the first plastic outer layer, the second long fiber filament composite layer, and the second plastic outer layer.

[0035] Step Six: Turn on the air cooler to cool the first and second plastic outer layers; turn on the composite pipe shaping cooling water tank to shape the composite pipe as a whole; turn on the first traction machine to pull the composite pipe; turn on the marking machine to mark the composite pipe; turn on the cutting machine to cut the composite pipe to a fixed length.

[0036] Compared with the prior art, the present invention provides a high-pressure resistant composite pipe structure and its production equipment and preparation method that are reinforced by long fiber filaments and continuous fiber tapes. By adding long glass fiber composite plastic (such as a first long fiber filament composite layer and a second long fiber filament composite layer) to the outermost layer, the overall reinforcing fiber content is higher and the thickness / volume of the reinforcing layer is larger, which significantly improves the overall load-bearing capacity of the composite pipe. It effectively solves the problem that traditional continuous fiber reinforced plastic composite pipes have limited reinforcing rigidity and insufficient ring stiffness of large-diameter products. It does not require excessive increase in the thickness of the inner and outer plastic layers, reduces manufacturing costs, and maintains the low-cost advantage.

[0037] Long glass fibers have a certain random orientation in the plane of the secondary outer layer or an orientation along the molding direction (such as the circumferential direction), which can supplement the shortcomings of continuous fibers (such as the first continuous fiber tape composite layer and the second continuous fiber tape composite layer) in different directions; for example, when the continuous winding is mainly axial, the long glass fiber secondary outer layer can provide reinforcement in the circumferential or other directions, reduce anisotropy, and make the overall performance of the composite tube more balanced.

[0038] Long glass fiber composite plastics have a three-dimensional reinforced structure and good impact toughness. The long fibers can bridge cracks and prevent crack propagation, making up for the defects of continuous fiber winding structure with single fiber orientation and low impact strength perpendicular to the fiber direction. When subjected to impact, the outermost long glass fiber can absorb energy through fiber pull-out and bridging mechanisms. In particular, when the surface layer is impacted, it can absorb most of the energy before the core continuous fiber winding structure fibers, protecting the core continuous fibers and improving the overall impact strength and toughness. Attached Figure Description

[0039] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments recorded in this invention. For those skilled in the art, other drawings can be obtained based on these drawings.

[0040] Figure 1 A schematic cross-sectional view of the end face of the gas delivery pipe is provided for an embodiment of the present invention;

[0041] Figure 2 A schematic cross-sectional view of the end face of the liquid conveying pipe is provided for embodiments of the present invention;

[0042] Figure 3 A side cross-sectional view of the gas delivery pipe is provided for an embodiment of the present invention.

[0043] Explanation of reference numerals in the attached figures:

[0044] 1. Gas conveying pipe; 11. First plastic inner layer; 12. First adhesive layer; 13. Barrier layer; 14. Second adhesive layer; 15. First continuous fiber tape composite layer; 16. First long fiber filament composite layer; 17. First plastic outer layer; 2. Liquid conveying pipe; 21. Second plastic inner layer; 22. Second continuous fiber tape composite layer; 23. Second long fiber filament composite layer; 24. Second plastic outer layer; 3. Composite pipe sealing joint; 31. Plastic sealing section; 32. Composite pipe section. Detailed Implementation

[0045] To enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below with reference to the accompanying drawings.

[0046] As attached Figure 1 To be continued Figure 3 As shown:

[0047] Example 1:

[0048] This invention provides a high-pressure resistant composite pipe structure for plastics reinforced with a combination of long fiber filaments and continuous fiber tape, comprising a gas conveying pipe 1 and a liquid conveying pipe 2;

[0049] The structural cross-section of the gas delivery pipe 1, from the inside to the outside, includes a first plastic inner layer 11, a first adhesive layer 12, a barrier layer 13, a second adhesive layer 14, a first continuous fiber tape composite layer 15, a first long fiber composite layer 16, and a first plastic outer layer 17, which are welded together sequentially.

[0050] The structural cross-section of the liquid conveying pipe 2, from the inside to the outside, includes a second plastic inner layer 21, a second continuous fiber tape composite layer 22, a second long fiber composite layer 23, and a second plastic outer layer 24, which are welded together sequentially.

[0051] The present invention is further described in detail. Both the gas delivery pipe 1 and the liquid delivery pipe 2 are provided with optical fiber cables 4 for tracking and testing pipe leakage inside the structural cross-section layer. The two optical fiber cables 4 are respectively arranged in the first long fiber composite layer 16 and the second long fiber composite layer 23.

[0052] The present invention is further described in detail as follows: the first continuous fiber tape composite layer 15 and the second continuous fiber tape composite layer 22 include a bidirectional double-layer tape consisting of a 0-degree unidirectional single-layer tape and a 0-degree unidirectional single-layer tape cross-laminated and fused together, wherein the fiber content of both the 0-degree unidirectional single-layer tape and the bidirectional double-layer tape cross-laminated and fused together is 30%-70%; the fiber content of the first long fiber filament composite layer 16 and the second long fiber filament composite layer 23 is 10%-50%, and the fiber length of the first long fiber filament composite layer 16 and the second long fiber filament composite layer 23 is 2-30 mm; the first adhesive layer 12 is respectively fused to the first plastic inner layer 11 and the barrier layer 13, and the second... The adhesive layer 14 is fused to the barrier layer 13 and the first continuous fiber tape composite layer 15 respectively. The first long fiber filament composite layer 16 is fused to the first continuous fiber tape composite layer 15 and the first plastic outer layer 17 respectively. The second continuous fiber tape composite layer 22 is connected to the second plastic inner layer 21 and the second long fiber filament composite layer 23 respectively. The second long fiber filament composite layer 23 is connected to the second continuous fiber tape composite layer 22 and the second plastic outer layer 24 respectively. The barrier tube layer designed to prevent gas permeation and escape is mainly composed of EVOH barrier material. The first plastic inner layer 11, the first adhesive layer 12, the barrier layer 13, and the second adhesive layer 14 together form the barrier structure.

[0053] The invention is further described in detail below. The ends of the gas conveying pipe 1 and the liquid conveying pipe 2 are respectively sealed by a first plastic inner layer 11 and a second plastic inner layer 21. The first plastic inner layer 11 and the second plastic inner layer 21 are processed into a heat-fused or electrofused connection pipe fitting for full network connectivity. This connection method can meet the requirements of preventing gas escape at the pipe end interface and simultaneously preventing gas escape throughout the network. On the other hand, it can withstand high pressure or ultra-high pressure requirements in sync with the composite pipe. The fibers include glass fiber, basalt fiber, carbon fiber, composite fibers of glass fiber and basalt fiber, composite fibers of glass fiber and carbon fiber, and composite fibers of basalt fiber and carbon fiber. The plastics include polypropylene, polyethylene, polybutene, polyvinyl chloride, ultra-high molecular weight polyethylene, nylon, and ABS. The gas conveyed by the gas conveying pipe 1 includes hydrogen, fuel gas, ammonia, carbon dioxide, and mixtures of hydrogen and fuel gas and mixtures of hydrogen and ammonia.

[0054] The present invention is further described in detail. One end of the gas conveying pipe 1 and the liquid conveying pipe 2 is provided with a composite pipe sealing joint 3. The composite pipe sealing joint 3 is composed of a plastic sealing section 31 and a composite pipe section 32 used for rounding, sizing and fusion of the composite pipe. The connection method uses long fiber reinforced composite pipe fittings as sleeve socket connectors, and connects the high pressure resistant composite pipe sealing pipe ends to form a pipeline system by electrofusion or hot fusion.

[0055] The preparation method of plastic sealing section 31 is as follows: first, the continuous fiber core layer with a fiber removal machine is removed to a depth of 1-10mm. The remaining inner and outer plastic layers of the tube end are heated in an oven and then extruded by an end mold to form a closed plastic section.

[0056] The method for preparing composite pipe section 32 is as follows: After the end of the continuous fiber-wound reinforced plastic composite pipe is heated to a molten state in an oven, under the combined action of the inner mold and the outer mold, the inner mold is inserted into the inner wall of the composite pipe end and expanded to round the composite pipe end. At the same time, the outer mold is inserted into and wraps around the outer wall of the composite pipe end and the composite pipe end is sized according to the standard outer diameter circumference. Under the combined action of the expansion force of the inner mold and the extrusion force of the outer mold, the inner and outer plastic layers and the continuous fiber core layer of the continuous fiber-wound reinforced plastic composite pipe end are fused together and combined with the plastic sealing section 31 to form a high-pressure resistant composite pipe sealing joint 3.

[0057] Working principle: First plastic inner layer 11: As the inner layer that is in direct contact with the transported gas, it plays a role in protecting the subsequent layers and initially bearing the gas pressure; its material properties must meet the compatibility with the transported gases such as hydrogen, fuel gas, ammonia, carbon dioxide, and mixtures of hydrogen and fuel gas and mixtures of hydrogen and ammonia, to prevent the gas from corroding or chemically reacting with the inner layer.

[0058] The first adhesive layer 12 is fused to the first plastic inner layer 11 and the barrier layer 13 respectively. Its function is to tightly bond the first plastic inner layer 11 and the barrier layer 13 together through its own adhesiveness, so as to ensure that the two layers will not separate when subjected to gas pressure, thus ensuring the integrity and sealing of the pipeline structure.

[0059] Barrier layer 13: It is mainly composed of EVOH barrier material, and together with the first plastic inner layer 11, the first adhesive layer 12 and the second adhesive layer 14, it forms a barrier structure. Since the molecules of gases such as hydrogen are small, they can easily escape through the gaps in the plastic crystals. EVOH material has excellent gas barrier performance, which can effectively prevent gas from permeating and escaping, and ensure the safety of gas transported in the pipeline.

[0060] The second adhesive layer 14 is fused to the barrier layer 13 and the first continuous fiber tape composite layer 15 respectively; its function is similar to that of the first adhesive layer 12, which firmly connects the barrier layer 13 and the first continuous fiber tape composite layer 15, so that the layers work together when the pipeline is under pressure, thereby enhancing the pipeline's pressure resistance.

[0061] The first continuous fiber tape composite layer 15 comprises a bidirectional double-layer tape consisting of a 0-degree unidirectional single-layer tape and a 0-degree unidirectional single-layer tape cross-laminated and fused together, with a fiber content of 30%–70% for both layers. The overall fiber content of the first long fiber composite layer 16 and the second long fiber composite layer 23 is 10%–50%, and the fiber length of the first long fiber composite layer 16 and the second long fiber composite layer 23 is 2–30 mm. The continuous fiber tape has a high tensile strength of 900–1200 MPa, which can withstand the gas pressure inside the pipeline and prevent the pipeline from rupturing due to excessive pressure. At the same time, its different fiber arrangement methods, unidirectional and bidirectional, can provide reinforcement in different directions, improve the ring stiffness and axial strength of the pipeline, reduce anisotropy, and make the pipeline performance more balanced.

[0062] The first long fiber composite layer 16 is fused to the first continuous fiber composite layer 15 and the first plastic outer layer 17 respectively. The long fibers have a certain random orientation in the plane of the second outer layer or along the forming direction of the second outer layer, such as circumferential orientation, which can supplement the shortcomings of continuous fibers in different directions. For example, when the continuous winding is mainly axial, the long glass fiber second outer layer may provide reinforcement in the circumferential or other directions, further improving the overall load-bearing capacity of the pipeline. In addition, the long fiber composite plastic has a three-dimensional reinforced structure with good impact toughness. The long fibers can bridge cracks and prevent crack propagation. When the pipeline is impacted, it can absorb energy through fiber pull-out, bridging and other mechanisms, improve the overall impact toughness, protect the core continuous fibers, and improve the overall impact strength and toughness of the pipeline. At the same time, it can also serve as a transition layer between the core continuous fibers and the outer plastic layer, alleviate the modulus difference between the core layer and the outer plastic layer, reduce interlayer stress concentration, improve interlayer shear strength, and reduce the risk of delamination.

[0063] The first plastic outer layer 17 serves as the outermost layer of the pipe, protecting the internal structures and preventing external environmental factors such as ultraviolet rays and chemicals from corroding the pipe. At the same time, it is tightly bonded to the first long fiber composite layer 16 to jointly withstand external pressure and impact.

[0064] The structural cross-section of the liquid conveying pipe 2, from the inside to the outside, includes a second plastic inner layer 21, a second continuous fiber tape composite layer 22, a second long fiber composite layer 23, and a second plastic outer layer 24, which are welded together sequentially.

[0065] The second plastic inner layer 21 is in direct contact with the liquid being transported. Its material must be compatible with the liquid being transported to prevent the liquid from corroding or chemically reacting with the inner layer, while also initially bearing the liquid pressure.

[0066] The second plastic outer layer 24 protects the internal structure and prevents external environmental factors from corroding the pipe. Together with the second long fiber composite layer 23, it can withstand external pressure and impact.

[0067] Both the gas delivery pipe 1 and the liquid delivery pipe 2 have fiber optic cables 4 installed inside their structural cross-sections for tracking and testing pipe leaks. The two fiber optic cables 4 are respectively installed in the first long fiber composite layer 16 and the second long fiber composite layer 23. When a leak occurs in the pipe, the medium at the leak location will change the environment around the fiber optic cable, causing changes in the characteristics of the optical signal transmitted in the fiber optic cable, such as light intensity and phase. By monitoring the changes in the optical signal, the location of the leak can be detected in a timely manner, enabling real-time monitoring and early warning of the pipe's operating status and ensuring the safe operation of the pipe.

[0068] The ends of the gas conveying pipe 1 and the liquid conveying pipe 2 are respectively sealed by a first plastic inner layer 11 and a second plastic inner layer 21. The first plastic inner layer 11 and the second plastic inner layer 21 are processed into a heat-fusion or electrofusion connection fitting for full network connectivity. This connection method, on the one hand, can form a good seal by using the sealing structure of the first plastic inner layer 11 and the second plastic inner layer 21 and the heat-fusion or electrofusion connection, which meets the requirements of preventing gas escape at the pipe end interface and simultaneously preventing gas escape throughout the network, ensuring that the conveyed gas will not leak from the pipe end; on the other hand, the first plastic inner layer 11 and the second plastic inner layer 21 have a certain strength and toughness, which can withstand the high pressure or ultra-high pressure requirements of the composite pipe, ensuring the reliability of the pipeline connection under high pressure environment.

[0069] Preparation and working principle of plastic sealing section 31: First, a fiber removal machine is used to remove the continuous fiber core layer to a depth of 1-10mm. This can remove some fibers in the core layer of the pipe end that may affect the seal. The remaining plastic layers inside and outside the pipe end are heated in an oven and then extruded by an end mold to form a closed plastic section. Heating softens the plastic layer, and the end mold extrusion shapes it into a closed structure, thereby achieving a seal on the pipe end and preventing the conveyed medium from leaking from the pipe end.

[0070] Preparation and working principle of composite pipe section 32: After the end of the continuous fiber-wound reinforced plastic composite pipe is heated to a molten state in an oven, under the combined action of the inner and outer molds of the socket extrusion, the inner mold is inserted into the inner wall of the composite pipe end and expands to round the composite pipe end, ensuring that the roundness of the pipe end meets the standard requirements and guaranteeing the tightness of the connection; at the same time, the outer mold is inserted into and wraps around the outer wall of the composite pipe end and sizing the composite pipe end with the standard outer diameter circumference, so that the outer diameter of the pipe end is accurate; under the combined action of the inner expansion force of the inner expansion mold and the extrusion force of the outer wrapping mold, the inner and outer plastic layers and the continuous fiber core layer of the continuous fiber-wound reinforced plastic composite pipe end are fused together and combined with the plastic sealing section 31 to form a high-pressure resistant composite pipe sealing joint 3; this fusion method tightly binds the layers together to form a whole, which can withstand high pressure and ensure the reliability and sealing of the pipeline connection; the connection method uses long fiber reinforced composite pipe fittings as sleeve socket connectors, and connects the high-pressure resistant composite pipe sealing ends to form a pipeline system by electrofusion or hot fusion, further enhancing the strength and sealing of the connection;

[0071] By adding long glass fiber composite plastic (such as the first long fiber composite layer 16 and the second long fiber composite layer 23) to the outermost layer, the overall reinforcing fiber content is higher and the thickness / volume of the reinforcing layer is larger, which significantly improves the overall load-bearing capacity of the composite pipe. This effectively solves the problem of insufficient ring stiffness of large-diameter products due to the limited reinforcing rigidity of traditional continuous fiber reinforced plastic composite pipes. It does not require excessive increase in the thickness of the inner and outer plastic layers, thus reducing manufacturing costs and maintaining the low-cost advantage.

[0072] The long glass fibers have a certain random orientation in the plane of the secondary outer layer or an orientation along the molding direction (such as the circumferential direction), which can supplement the shortcomings of continuous fibers (such as the first continuous fiber tape composite layer 15 and the second continuous fiber tape composite layer 22) in different directions; for example, when the continuous winding is mainly axial, the long glass fiber secondary outer layer can provide reinforcement in the circumferential or other directions, reduce anisotropy, and make the overall performance of the composite tube more balanced.

[0073] Long glass fiber composite plastics have a three-dimensional reinforced structure and good impact toughness. The long fibers can bridge cracks and prevent crack propagation, making up for the defects of continuous fiber winding structure with single fiber orientation and low impact strength perpendicular to the fiber direction. When subjected to impact, the outermost long glass fiber can absorb energy through fiber pull-out and bridging mechanisms. In particular, when the surface layer is impacted, it can absorb some energy before the core layer, protect the continuous fibers of the core layer, and improve the overall impact strength and toughness.

[0074] In a multilayer structure, the addition of long-fiber composite plastic to the outermost layer increases the number of interfaces (such as between the core layer and the outermost layer, and between the outermost layer and the outer plastic layer). The multilayer reinforcement forms a gradient structure, which alleviates the modulus difference between the core layer (such as the first continuous fiber ribbon composite layer 15 and the second continuous fiber ribbon composite layer 22) and the outer plastic layer (such as the first plastic outer layer 17 and the second plastic outer layer 24), reduces interlayer stress concentration, improves interlayer shear strength, and reduces the risk of delamination. Plastic materials themselves have a tendency to creep, and glass fiber reinforcement can significantly improve creep resistance. The long glass fiber composite plastic of the outermost layer works synergistically with the long glass fiber of the core layer to make the overall rigidity higher, the structure has better creep resistance, and less deformation under long-term load.

[0075] Enhanced fatigue resistance: The fatigue performance of fiber-reinforced composites is related to the fiber-matrix interface bonding and stress distribution; joint reinforcement disperses stress in more reinforcing fibers, reduces the fatigue load of a single reinforcing layer, and thus improves the overall fatigue resistance.

[0076] By using EVOH material to make the barrier layer 13, and using hot melt adhesive to connect the EVOH material layer with the plastic and continuous fiber layers to form a whole, the problem of preventing gas escape from the pipeline network is effectively solved. In particular, for transporting gases with the lightest and smallest molecular structure, such as hydrogen, gas escape from the gaps in the plastic of the composite pipe body is avoided, and the hydrogen embrittlement problem that may occur when transporting hydrogen in steel pipes is solved. The core layer is made of a high tensile strength (900-1200MPa) continuous fiber tape composite layer, which solves the dual problems of high pressure resistance and gas corrosion resistance of the composite pipe body, ensuring stable operation of the composite pipe under high pressure environment and effectively resisting gas corrosion of the pipe body.

[0077] By employing specific sealing pipe end technology, the problem of gas or liquid media leaking into the fiber layer and causing failure is avoided. This also prevents media leakage from the fusion joint due to inaccurate circumference and outer diameter dimensions of the composite pipe end, and avoids joint failure caused by delamination of the composite pipe end leading to the inability of the fusion joint to withstand axial tensile stress, thus improving the sealing performance and reliability of the pipeline system. Using homogeneous pipe fittings to manufacture thermofusion or electrofusion connection fittings not only prevents gas from escaping from the pipe joint, ensuring the gas tightness of the pipeline system, but also reduces the cost of connecting fittings, including materials and manufacturing costs, improving economic efficiency.

[0078] Example 2:

[0079] This embodiment is basically the same as the previous embodiment, except that the production equipment for a high-pressure resistant composite pipe structure reinforced by long fiber filaments and continuous fiber tapes includes the following apparatus:

[0080] Multiple inner tube extruders and inner tube multi-layer co-extrusion composite mold: Multiple inner tube extruders heat and melt the materials of the first plastic inner layer 11, the first adhesive layer 12, the barrier layer 13, the second adhesive layer 14, and the second plastic inner layer 21, and then extrude them; the inner tube multi-layer co-extrusion composite mold, through precise design and control, can realize the synchronous extrusion and composite of each layer of materials, so that each layer is accurately composited together in the set order and thickness, thereby improving production efficiency and product quality;

[0081] Inner tube vacuum sizing cooling water tank: It is set at the front end of the inner tube multi-layer co-extrusion composite mold. After the extruded inner tube enters the water tank, it is sizing tightly against the inner wall of the sizing sleeve under negative pressure by the vacuum sizing device, thereby ensuring the dimensional accuracy of the inner tube and making its outer diameter and wall thickness meet the design requirements.

[0082] Inner tube shaping cooling water tank: Located at the front end of the vacuum sizing cooling water tank, the inner tube enters this water tank after vacuum sizing for further cooling and shaping; through the circulation of cooling water, the inner tube maintains a stable shape during the cooling process, preventing deformation of the inner tube due to temperature changes and ensuring the quality of the inner tube.

[0083] First traction machine: Located at the front end of the inner tube shaping cooling water tank, it applies a certain pulling force to the inner tube through the traction device, so that it moves forward at a certain speed, ensuring the continuity of production and ensuring that each production link can be carried out in an orderly manner;

[0084] Multiple sets of continuous fiber winding discs: used to produce the first continuous fiber tape composite layer 15 and the second continuous fiber tape composite layer 22, and set at the front end of the first traction machine; through the rotation of the continuous fiber winding discs and the fiber conveying device, the fibers can be evenly wound on the inner tube to form a continuous fiber tape composite layer; the winding angle and tension of the fibers can be precisely controlled by the equipment to meet different performance requirements;

[0085] The fiber optic laying machine is located at the front end of the continuous fiber winding reel and is used to lay fiber optic cables 4.

[0086] The outer tube extruder and the outer tube composite co-extrusion die are set at the front end of the optical fiber laying machine. The materials of the first long fiber composite layer 16, the first plastic outer layer 17, the second long fiber composite layer 23, and the second plastic outer layer 24 are heated, melted, and extruded. The outer tube composite co-extrusion die can realize the synchronous extrusion and composite of the materials of each layer of the outer tube, so that each layer is accurately composited together to form a complete outer tube structure.

[0087] Cooling air blower: Located at the front end of the outer tube composite co-extrusion die, it cools the extruded first plastic outer layer 17 and second plastic outer layer 24; the cooling air can accelerate the cooling and solidification of the plastic, so that the plastic outer layer can be quickly shaped, improve production efficiency, and at the same time ensure the surface quality of the plastic outer layer.

[0088] Composite pipe integral shaping cooling water tank: installed at the front end of the air cooler, it shapes the composite pipe as a whole; through the comprehensive cooling of the cooling water, it ensures that the layers of the composite pipe are tightly bonded, eliminates the stress between the layers, and makes the composite pipe dimensionally stable and uniform in performance.

[0089] The second traction machine is located at the front end of the composite pipe shaping cooling water tank. It is used to pull the composite pipe forward at a certain speed to ensure the continuity of production. It works in conjunction with the first traction machine to ensure the stability of the entire production process.

[0090] Marking machine: Located at the front end of the second traction machine, it marks the composite pipe; by printing or spraying, it marks product information such as specifications, model, production date, etc. on the surface of the composite pipe to facilitate product identification and management;

[0091] Cutting machine: Located at the front end of the marking machine, it cuts the composite pipe to the set length; the cutting machine can precisely control the cutting length to meet the usage requirements of different lengths, making the composite pipe easy to transport and install;

[0092] Receiving table: Located at the front of the cutting machine, it is used to collect the cut composite pipes; the receiving table can neatly stack the cut composite pipes, which is convenient for subsequent packaging and transportation, and improves production efficiency.

[0093] Through the above technical solution, in the production equipment, the inner tube extruder is connected to the inner tube multi-layer co-extrusion composite die, which enables the simultaneous extrusion and composite of each layer of materials (such as the first plastic inner layer 11, the first adhesive layer 12, the barrier layer 13, the first adhesive layer 12, and the second plastic inner layer 21), thereby improving production efficiency and product quality. The outer tube extruder is connected to the outer tube composite co-extrusion die, which similarly enables the simultaneous extrusion and composite of each layer of materials in the outer tube (such as the first long fiber composite layer 16, the first plastic outer layer 17, the second long fiber composite layer 23, and the second plastic outer layer 24).

[0094] The inner tube vacuum sizing cooling water tank and the inner tube shaping cooling water tank respectively sizing and shaping the extruded inner tube, ensuring dimensional accuracy and stable shape. The composite tube integral shaping cooling water tank shapes the composite tube as a whole, ensuring tight bonding between the layers and dimensional stability, further improving product quality. The first and second traction machines respectively pull the inner tube and composite tube, moving them forward at a certain speed to ensure continuous production. The marking machine marks the composite tubes for easy product identification and management. The cutting machine cuts composite tubes to a fixed length to meet different length requirements. The receiving table collects the cut composite tubes for subsequent packaging and transportation, making the entire production process efficient and orderly.

[0095] Example 3:

[0096] This embodiment is basically the same as the previous embodiment, except that the method for preparing a high-pressure resistant composite pipe structure reinforced by a combination of long fiber filaments and continuous fiber tape includes the following steps:

[0097] The materials of the first plastic inner layer 11, the first adhesive layer 12, the barrier layer 13, the second adhesive layer 14, and the second plastic inner layer 21 are respectively loaded into the corresponding inner tube extruder hoppers;

[0098] The first continuous fiber tape composite layer 15 is loaded onto the winding machine disc; then the first long fiber composite layer 16, the first plastic outer layer 17, the second long fiber composite layer 23, and the second plastic outer layer 24 are respectively loaded into the corresponding multiple outer tube extruder hoppers; ensuring that all materials are accurately positioned to prepare for subsequent production.

[0099] Multiple inner tube extruders and their connected composite molds are turned on, and the material loaded into the hopper is heated and melted and then extruded to form an inner tube melt composed of a first plastic inner layer 11, a first adhesive layer 12, a barrier layer 13 and a second adhesive layer 14; by precisely controlling the temperature, pressure and screw speed of the extruders, the quality and stability of the inner tube melt are ensured.

[0100] The first traction machine is started, and under the drive of the traction pipe, the inner tube melt is pulled into the inner tube vacuum sizing cooling water tank for sizing, so that the inner tube size meets the requirements; then it enters the inner tube shaping cooling water tank for shaping, so that the inner tube shape is stable.

[0101] Multiple sets of continuous fiber winding discs are activated to produce the first continuous fiber tape composite layer 15 and the second continuous fiber tape composite layer 22; simultaneously, multiple outer tube extruders and their connected outer tube composite co-extrusion dies are activated to produce the first long fiber filament composite layer 16, the first plastic outer layer 17, the second long fiber filament composite layer 23, and the second plastic outer layer 24; by precisely controlling the winding parameters of the winding discs and the extrusion parameters of the outer tube extruders, the quality and performance of each layer are ensured.

[0102] Turn on the air cooler to cool the first plastic outer layer 17 and the second plastic outer layer 24, accelerating the cooling and curing of the plastic; turn on the composite tube shaping cooling water tank to shape the composite tube as a whole, so that the layers are tightly bonded and the dimensions are stable.

[0103] Start the second traction machine to pull the composite pipe; start the marking machine to mark the composite pipe; start the cutting machine to cut the composite pipe to a fixed length to meet different usage requirements; finally, collect the cut composite pipes on the receiving platform to complete the entire production process.

[0104] The foregoing has only described certain exemplary embodiments of the present invention by way of illustration. Undoubtedly, those skilled in the art can modify the described embodiments in various ways without departing from the spirit and scope of the present invention. Therefore, the foregoing drawings and descriptions are illustrative in nature and should not be construed as limiting the scope of protection of the claims of the present invention.

Claims

1. A high-pressure resistant plastic composite pipe structure reinforced with a combination of long fiber filaments and continuous fiber tape, characterized in that, It includes a gas delivery pipe (1) and a liquid delivery pipe (2); The structural cross-section of the gas delivery pipe (1) consists of a first plastic inner layer (11), a first adhesive layer (12), a barrier layer (13), a second adhesive layer (14), a first continuous fiber tape composite layer (15), a first long fiber composite layer (16), and a first plastic outer layer (17), which are welded together from the inside to the outside. The structural cross-section of the liquid conveying pipe (2) consists of a second plastic inner layer (21), a second continuous fiber tape composite layer (22), a second long fiber composite layer (23), and a second plastic outer layer (24), which are welded together from the inside to the outside.

2. The high-pressure resistant composite pipe structure of long fiber filaments and continuous fiber tapes reinforced plastic according to claim 1, characterized in that, Both the gas delivery pipe (1) and the liquid delivery pipe (2) have fiber optic cables (4) inside their structural cross-sections for tracking and testing pipe leakage. The two fiber optic cables (4) are respectively located in the first long fiber composite layer (16) and the second long fiber composite layer (23).

3. The high-pressure resistant composite pipe structure of long fiber filaments and continuous fiber tapes reinforced plastic according to claim 1, characterized in that, The first continuous fiber tape composite layer (15) and the second continuous fiber tape composite layer (22) include a bidirectional double-layer tape with 0-degree unidirectional single-layer tape and 0-degree unidirectional single-layer tape cross-layered and fused together, and the fiber ratio of the bidirectional double-layer tape with 0-degree unidirectional single-layer tape and 0-degree unidirectional single-layer tape cross-layered and fused together is 30%-70%; the fiber ratio of the first long fiber filament composite layer (16) and the second long fiber filament composite layer (23) is 10%-50%, and the fiber length of the first long fiber filament composite layer (16) and the second long fiber filament composite layer (23) is 2-30mm.

4. The high-pressure resistant composite pipe structure of long fiber filaments and continuous fiber tapes reinforced plastic according to claim 1, characterized in that, The first adhesive layer (12) is fused to the first plastic inner layer (11) and the barrier layer (13) respectively. The second adhesive layer (14) is fused to the barrier layer (13) and the first continuous fiber composite layer (15) respectively. The first long fiber composite layer (16) is fused to the first continuous fiber tape composite layer (15) and the first plastic outer layer (17) respectively. The second continuous fiber tape composite layer (22) is connected to the second plastic inner layer (21) and the second long fiber composite layer (23) respectively. The second long fiber composite layer (23) is connected to the second continuous fiber tape composite layer (22) and the second plastic outer layer (24) respectively.

5. The high-pressure resistant composite pipe structure of long fiber filaments and continuous fiber tapes reinforced plastic according to claim 1, characterized in that, The ends of the gas conveying pipe (1) and the liquid conveying pipe (2) are respectively sealed by a first plastic inner layer (11) and a second plastic inner layer (21); the fibers include glass fiber, basalt fiber, carbon fiber, composite fiber of glass fiber and basalt fiber, composite fiber of glass fiber and carbon fiber, and composite fiber of basalt fiber and carbon fiber; the plastics include polypropylene, polyethylene, polybutene, polyvinyl chloride, ultra-high molecular weight polyethylene, nylon, and ABS; the conveying gas of the gas conveying pipe (1) includes hydrogen, fuel gas, ammonia, carbon dioxide, and a mixture of hydrogen and fuel gas and a mixture of hydrogen and ammonia.

6. The high-pressure resistant composite pipe structure of long fiber filaments and continuous fiber tapes reinforced plastic according to claim 1, characterized in that, One end of the gas conveying pipe (1) and the liquid conveying pipe (2) is provided with a composite pipe sealing joint (3). The composite pipe sealing joint (3) is composed of a plastic sealing section (31) and a composite pipe section (32) used for rounding, sizing and fusion of the composite pipe. The preparation method of the plastic sealing section (31) is as follows: first, the continuous fiber core layer is removed by a fiber removal machine to a depth of 1-10mm, and the remaining inner and outer plastic layers of the tube end are heated in an oven and then extruded by an end mold to form a closed plastic section. The method for preparing the composite pipe section (32) is as follows: After the end of the continuous fiber-wound reinforced plastic composite pipe is heated in an oven to a molten state, under the combined action of the inner mold and the outer mold, the inner mold is inserted into the inner wall of the composite pipe end to expand to round the composite pipe end, and at the same time, the outer mold is inserted into and wraps around the outer wall of the composite pipe end to calibrate the composite pipe end with the standard outer diameter circumference; under the combined action of the inner expansion force of the inner expansion mold and the extrusion force of the outer wrapping mold, the inner and outer plastic layers, long fiber layers and continuous fiber core layers of the continuous fiber-wound reinforced plastic composite pipe end are fused together with the plastic sealing section (31) to form a high-pressure resistant composite pipe sealing joint (3).

7. The production equipment for a high-pressure resistant plastic composite pipe structure reinforced with long fiber filaments and continuous fiber tapes according to any one of claims 1-6, characterized in that, Includes the following devices: Multiple inner tube extruders are connected to an inner tube multi-layer co-extrusion composite mold for producing a first plastic inner layer (11), a first adhesive layer (12), a barrier layer (13), a first adhesive layer (14), and a second plastic inner layer (21). The inner tube vacuum sizing cooling water tank is located at the front end of the inner tube multi-layer co-extrusion composite mold and is used to sizing the extruded inner tube to ensure the dimensional accuracy of the inner tube. The inner tube shaping cooling water tank is located at the front end of the vacuum sizing cooling water tank and is used to shape the inner tube so that the inner tube maintains a stable shape during the cooling process. The first traction machine is located at the front end of the inner tube shaping cooling water tank. It is used to pull the inner tube so that it moves forward at a certain speed to ensure the continuity of production. Multiple sets of continuous fiber winding discs, used to produce the first continuous fiber tape composite layer (15) and the second continuous fiber tape composite layer (22), are set at the front end of the first traction machine; The fiber optic laying machine is set at the front end of the continuous fiber winding reel and is used to lay fiber optic cables (4). The outer tube extruder is connected to an outer tube composite co-extrusion die, which is set at the front end of the optical fiber laying machine and is used to produce the first long fiber composite layer (16), the first plastic outer layer (17), the second long fiber composite layer (23), and the second plastic outer layer (24). A cooling fan is installed at the front end of the outer tube composite co-extrusion die to cool the extruded first plastic outer layer (17) and second plastic outer layer (24). The composite pipe integral shaping cooling water tank is located at the front end of the air cooler and is used to shape the composite pipe as a whole. The second traction machine is located at the front end of the composite pipe shaping cooling water tank. It is used to pull the composite pipe forward at a certain speed to ensure the continuity of production. The marking machine, located at the front end of the second traction machine, is used to mark the composite pipes; A cutting machine, located at the front end of the marking machine, is used to cut composite pipes of a fixed length. The receiving platform, located at the front end of the cutting machine, is used to collect the cut composite pipes.

8. A method for preparing a high-pressure resistant plastic composite pipe structure reinforced with long fiber filaments and continuous fiber tape according to any one of claims 1-6, characterized in that, Includes the following steps: Step 1: Load the materials of the first plastic inner layer (11), the first adhesive layer (12), the barrier layer (13), the second adhesive layer (14), and the second plastic inner layer (21) into the corresponding inner tube extruder hoppers respectively; Step 2: Load the first continuous fiber tape composite layer (15) onto the winding machine disc; then load the first long fiber composite layer (16), the first plastic outer layer (17), the second long fiber composite layer (23), and the second plastic outer layer (24) into the corresponding multiple outer tube extruder hoppers respectively; Step 3: Start multiple inner tube extruders and their connected composite molds to extrude the inner tube melt composed of the first plastic inner layer (11), the first adhesive layer (12), the barrier layer (13), and the second adhesive layer (14); Step 4: Start the first traction machine. Driven by the traction pipe, the inner tube melt is pulled into the inner tube vacuum sizing cooling water tank. Step 5: Open the inner tube vacuum sizing cooling water tank to sizing the inner tube; open the inner tube shaping cooling water tank to shape the inner tube; open multiple sets of continuous fiber winding discs to produce the first continuous fiber tape composite layer (15) and the second continuous fiber tape composite layer (22); open multiple outer tube extruders and their connected outer tube composite co-extrusion dies to produce the first long fiber filament composite layer (16), the first plastic outer layer (17), the second long fiber filament composite layer (23), and the second plastic outer layer (24). Step 6: Turn on the air cooler to cool the first plastic outer layer (17) and the second plastic outer layer (24); turn on the composite pipe shaping cooling water tank to shape the composite pipe as a whole; turn on the second traction machine to pull the composite pipe; turn on the marking machine to mark the composite pipe; turn on the cutting machine to cut the composite pipe to a fixed length.

Images