Insulated high pressure tensile composite pipe

Abstract

The utility model provides an insulating tensile high pressure composite pipe belongs to insulating wire pipe technical field, this insulating tensile high pressure composite pipe includes inner tube layer and outer tube layer, is provided with reinforcing layer between inner tube layer and outer tube layer, inner tube layer is made of insulating material, outer tube layer is made of weather resistance insulating material, reinforcing layer is made of tensile fibre material, the inner surface of reinforcing layer and the outer surface of inner tube layer close fit, the outer surface of reinforcing layer and the inner surface of outer tube layer close fit, reinforcing layer is along the axial helical winding structure of pipe body, and there is crossing angle between helical winding adjacent layer, the inner diameter size of inner tube layer is less than the inner diameter size of outer tube layer, and the thickness of reinforcing layer accounts for the main part of entire composite pipe wall thickness, the utility model can solve the problem that the tensile strength and insulating performance of existing insulating pipe body are insufficient under the overhead laying occasion of high load, large span, lead to the problem of influencing the safe and stable operation of high voltage transmission line.

Description

Technical Field

[0001] This utility model belongs to the field of insulated conduit technology, specifically, it relates to an insulated tensile high-voltage composite pipe. Background Technology

[0002] In power systems, the safe and stable operation of high-voltage transmission lines and cables is crucial for the reliable power supply of the entire grid. With the continuous growth of electricity demand and the extension of transmission distances, the scale of high-voltage transmission line construction is becoming increasingly larger, especially in complex terrain conditions such as mountainous areas and crossing rivers, where the span of overhead transmission lines often reaches hundreds or even thousands of meters. In these applications, transmission lines and cables need to be encased in protective conduits to provide both mechanical and insulation protection.

[0003] Traditional protective conduits mainly fall into two categories: plastic pipes and metal pipes. Plastic pipes offer good insulation and are relatively lightweight, but their mechanical strength is low. When laid over long spans, they are prone to tensile deformation due to their own weight and external loads, which can lead to pipe breakage and disrupt the normal operation of transmission lines. While metal pipes possess high mechanical strength, their conductivity makes them unsuitable for direct use in protecting high-voltage electrical equipment. An external insulation layer must be added, which not only increases the weight and cost of the pipe but also complicates the structure. Currently, a common approach in engineering practice is to use reinforced plastic pipes, which increase strength by increasing the wall thickness or adding fillers to ordinary plastic pipes. However, this method has limited effectiveness; the weight of the pipe increases significantly without a substantial improvement in strength, and material utilization is low. Another approach is to use metal pipes with an external insulation layer. However, the weight of the metal pipes significantly increases the difficulty of overhead laying and the burden on the supporting structure. Furthermore, the bonding between the metal and the insulation layer also affects overall performance. Therefore, there is an urgent need in the existing technology for a lightweight protective pipe that has both excellent insulation performance and high tensile strength to meet the actual needs of long-span high-voltage transmission lines and cable laying. Utility Model Content

[0004] In view of this, the present invention provides an insulated tensile high-voltage composite pipe, which can solve the problem that the existing insulated pipe body is not strong enough in terms of tensile strength and insulation performance in overhead laying applications with high load and large span, which affects the safe and stable operation of high-voltage transmission lines.

[0005] This utility model is implemented as follows:

[0006] This utility model provides an insulated tensile high-voltage composite pipe, comprising an inner tube layer and an outer tube layer, wherein a reinforcing layer is disposed between the inner tube layer and the outer tube layer; the inner tube layer is made of insulating material, the outer tube layer is made of weather-resistant insulating material, and the reinforcing layer is made of tensile fiber material; the inner surface of the reinforcing layer is tightly bonded to the outer surface of the inner tube layer, and the outer surface of the reinforcing layer is tightly bonded to the inner surface of the outer tube layer; the reinforcing layer has a spiral winding structure along the axial direction of the pipe body, and there is an intersection angle between adjacent spiral winding layers; the inner diameter of the inner tube layer is smaller than the inner diameter of the outer tube layer, and the thickness of the reinforcing layer accounts for at least two-thirds of the total wall thickness of the composite pipe.

[0007] The technical advantages of the insulating tensile high-voltage composite pipe provided by this utility model are as follows: By tightly bonding the inner tube layer, the reinforcing layer, and the outer tube layer to form a composite pipe body, the inner tube layer provides insulation protection, the reinforcing layer provides tensile strength, and the outer tube layer provides weather protection. The synergistic effect of the three layers achieves an organic combination of insulation performance and mechanical strength. The reinforcing layer adopts a spiral winding structure and is tightly bonded to the inner and outer tube layers, so that the stress can be evenly distributed throughout the entire pipe wall structure when external force is applied, avoiding local damage caused by stress concentration. There are intersecting angles between adjacent spiral winding layers, so that the fibers form a load-bearing network in different directions, which significantly improves the tensile performance and overall structural stability of the composite pipe in multiple directions.

[0008] Based on the above technical solution, the insulating tensile high-voltage composite pipe of this utility model can be further improved as follows:

[0009] The spiral winding angle of the reinforcing layer is in the range of 45° to 65° relative to the axial direction of the tube.

[0010] The beneficial effects of adopting the above-mentioned improved scheme are as follows: by limiting the spiral winding angle of the reinforcing layer to an angle range of 45° to 65° relative to the axial direction of the tube, the fiber material can provide effective load-bearing capacity in both the axial and circumferential directions; this angle range allows the spiral fibers to convert the tension into the tensile stress of the fiber itself through its tilt direction when the composite tube is subjected to axial tensile force, giving full play to the high tensile strength characteristics of the fiber material; at the same time, this angle range also ensures that the composite tube has sufficient circumferential restraint force when subjected to radial pressure or internal pressure, preventing radial expansion deformation of the tube body, and achieving the best balance between axial tensile and radial compressive strength.

[0011] Furthermore, the ratio of the thickness of the inner tube layer to the thickness of the reinforcing layer is 1:3 to 1:5.

[0012] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: by controlling the ratio of the thickness of the inner tube layer to the thickness of the reinforcing layer within the range of 1:3 to 1:5, the reinforcing layer occupies the main thickness of the pipe wall, giving full play to the high strength characteristics of the tensile fiber material and significantly improving the overall load-bearing capacity of the composite pipe; this thickness ratio configuration ensures that the inner tube layer has sufficient thickness to provide reliable insulation performance, while not weakening the load-bearing function of the reinforcing layer due to excessive thickness of the inner tube layer; this thickness ratio allows the composite pipe to use the limited pipe wall space mainly for the reinforcing structure while ensuring insulation performance, thereby optimizing material utilization and maximizing comprehensive performance.

[0013] Furthermore, the reinforcing layer adopts a multi-layer spiral winding structure, with adjacent spiral winding layers winding in opposite directions.

[0014] The beneficial effects of adopting the above-mentioned improved scheme are as follows: by adopting a multi-layer spiral winding structure and making the winding directions of adjacent spiral winding layers opposite, a fiber network structure of alternating positive and negative directions is formed, so that fiber layers in different directions intertwine to form a stable load-bearing system; fiber layers with opposite winding directions can restrain each other when under stress, effectively suppressing torsional deformation that may be generated by a single winding direction; this staggered winding structure enables the composite pipe to work together to bear the load when subjected to complex stress states, avoiding the premature strength limit of a certain layer of fiber leading to the failure of the overall structure, and significantly improving the tensile strength and torsional resistance of the composite pipe.

[0015] Furthermore, the outer surface of the outer tube layer is provided with several axially extending ribs, which are distributed at equal intervals around the outer circumference of the outer tube layer.

[0016] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: By setting several axially extending ribs on the outer surface of the outer tube layer and distributing them at equal intervals around it, the surface area and structural stiffness of the outer tube layer are increased, making the outer tube layer more resistant to deformation when subjected to external impact or extrusion; the presence of the ribs forms a reinforcing rib structure, which effectively improves the local bending stiffness and overall stability of the tube body; the ribs distributed at equal intervals around it ensure that the stiffness enhancement effect is evenly distributed in the circumferential direction of the tube body, avoiding the occurrence of local weak points; the ribs can also play a guiding and positioning role during the installation and use of the composite pipe, making it convenient for the tube body to be installed and fixed in the support or pipeline.

[0017] Furthermore, the cross-section of the rib is trapezoidal, with the width of the upper base being smaller than the width of the lower base, and the height of the rib being one-third to one-half of the wall thickness of the outer tube layer.

[0018] The beneficial effects of adopting the above-mentioned improved scheme are as follows: by designing the cross-section of the rib as a trapezoidal structure with the upper base width being smaller than the lower base width, the rib has good anti-overturning stability and is less prone to root fracture when subjected to lateral forces; the trapezoidal structure of the rib has a large connection area between the bottom of the rib and the outer tube layer, which can effectively disperse stress and avoid stress concentration; controlling the height of the rib within one-third to one-half of the outer tube layer wall thickness ensures that the rib has sufficient reinforcement while avoiding material waste and uneven stress caused by excessively high ribs; the narrower top of the trapezoidal cross-section results in a smaller contact area when the rib comes into contact with other objects, reducing frictional resistance and facilitating the installation and maintenance of the tube.

[0019] Furthermore, the inner surface of the inner tube layer is smooth and flat, and the inner tube layer and the reinforcing layer are tightly bonded together by an adhesive layer, with the thickness of the adhesive layer being evenly distributed.

[0020] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: by keeping the inner surface of the inner tube layer smooth and flat, the frictional resistance of fluid or cable flowing or passing through the pipe is reduced, thus reducing energy loss; the smooth inner surface avoids the interference of protrusions or depressions on fluid flow and prevents the generation of turbulence; by setting an adhesive layer between the inner tube layer and the reinforcing layer to achieve a tight fit, the gaps between layers are eliminated, avoiding structural loosening and performance degradation caused by interlayer slippage during use; the uniformly distributed adhesive layer thickness ensures the consistency of bonding strength in all parts, so that the inner tube layer and the reinforcing layer form an integral and synergistic force-bearing structure, giving full play to the advantages of the composite structure.

[0021] Furthermore, the tensile fiber material of the reinforcing layer is glass fiber or aramid fiber, and the fiber bundles are kept taut during the spiral winding process.

[0022] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: By selecting glass fiber or aramid fiber as the tensile fiber material for the reinforcing layer, the overall load-bearing capacity of the composite pipe is significantly improved by utilizing the excellent tensile strength and modulus characteristics of these materials; glass fiber has good insulation properties and high cost performance, while aramid fiber has higher specific strength and fatigue resistance. Both materials are well-known high-performance fiber materials; by maintaining the tension of the fiber bundle during the spiral winding process, fiber relaxation and wrinkles are eliminated, allowing the strength of the fiber material to be fully utilized; the tensioned fibers form a prestressed structure after curing, which can exert a beneficial constraint on the pipe body before the composite pipe bears external loads, improving the composite pipe's resistance to deformation and service life.

[0023] Furthermore, the grooves between the ribs on the outer surface of the outer tube layer have an arc-shaped transition structure, and the bottom of the grooves forms a smooth connection with the outer surface of the main body of the outer tube layer.

[0024] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: by designing the groove between the ribs on the outer surface of the outer tube layer as an arc-shaped transition structure, the stress concentration phenomenon that may be caused by sharp corners or right angle transitions is avoided, thereby improving the resistance of the outer tube layer to damage when subjected to external forces; the arc-shaped transition makes the bottom of the groove form a smooth connection with the main body of the outer tube layer, and the stress can be smoothly transferred in this area, reducing the risk of crack initiation and propagation; the smooth arc-shaped transition structure also facilitates the demolding operation of the outer tube layer during the production process, improving the molding quality of the product; the design of the arc-shaped groove makes it difficult for dirt to accumulate on the outer surface of the composite pipe during cleaning and maintenance, maintaining the cleanliness of the pipe body appearance and the stability of long-term performance.

[0025] Furthermore, the composite pipe is provided with connecting ends at both ends. The outer diameter of the connecting ends is larger than the outer diameter of the middle section of the pipe body, and the inner diameter of the connecting ends is consistent with the inner diameter of the middle section of the pipe body. The outer surface of the connecting ends is provided with an annular boss for positioning and installation.

[0026] The beneficial effects of adopting the above-mentioned improvement scheme are as follows: By setting connecting ends with an outer diameter larger than that of the middle section of the pipe at both ends of the composite pipe, a structural feature that facilitates installation and connection is formed, allowing the composite pipe to be easily connected with other pipes or equipment; the inner diameter of the connecting end is consistent with that of the middle section of the pipe, ensuring the continuity of the internal channel and avoiding obstruction of fluid flow or cable passage; the annular boss set on the outer surface of the connecting end provides a reliable support surface for positioning and fixing during installation, enabling the composite pipe to be accurately positioned during installation and preventing poor sealing or uneven stress caused by installation deviation; the enlarged outer diameter structure of the connecting end can also withstand the clamping or fastening force applied during installation, preventing damage to the middle section of the pipe due to excessive local stress.

[0027] Compared with existing technologies, the beneficial effects of the insulated tensile high-voltage composite pipe provided by this utility model are as follows: Through a three-layer composite structure consisting of an inner tube layer, a reinforcing layer, and an outer tube layer, and using a spirally wound reinforcing layer as the main load-bearing component, the organic unity of insulation performance and tensile strength is achieved, effectively solving the technical problem of traditional protective pipes being unable to simultaneously achieve both strength and insulation performance. The inner tube layer uses insulating materials to provide reliable electrical insulation protection; the reinforcing layer uses high-strength tensile fiber materials and fully utilizes the load-bearing capacity of the fibers through a spiral winding structure; and the outer tube layer uses weather-resistant insulating materials to provide protection for the internal structure and a secondary insulation barrier. The three-layer structure is tightly bonded to form a whole, enabling each layer to work collaboratively to withstand external loads, significantly improving the overall performance of the composite pipe. The spirally wound reinforcing layer uses a fiber network structure formed by interlaced winding, giving the composite pipe excellent tensile strength when subjected to axial tension, while also possessing good bending and torsional resistance. The raised rib structure in the outer tube layer further enhances the local stiffness and overall stability of the pipe body, enabling the composite pipe to adapt to various complex operating environments and load conditions. The composite pipe of this invention has a reasonable structure, excellent performance, and mature manufacturing process. It is particularly suitable for overhead laying of high-voltage transmission lines and protection of long-distance cables, and can significantly improve the safety and reliability of transmission lines. It has broad application prospects and significant economic benefits. Attached Figure Description

[0028] To more clearly illustrate the technical solutions of the embodiments of this utility model, the drawings used in the description of the embodiments of this utility model will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic diagram of the exploded structure of an insulating tensile high-voltage composite pipe;

[0030] Figure 2 A schematic diagram of the spiral winding layer of an insulating tensile high-voltage composite pipe;

[0031] Figure 3 This is a schematic diagram of a cross-section of an insulating tensile high-voltage composite pipe;

[0032] The attached diagram lists the components represented by each number as follows:

[0033] 10. Inner tube layer; 11. Outer tube layer; 12. Reinforcing layer; 13. Spiral winding layer; 14. Rib; 15. Adhesive layer; 16. Groove; 17. Connecting end; 18. Middle section of tube body; 19. Annular boss. Detailed Implementation

[0034] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings.

[0035] like Figure 1-3 The illustration shows an embodiment of an insulated, tensile-resistant, high-voltage composite pipe provided by this utility model. In this embodiment, it includes an inner pipe layer 10 and an outer pipe layer 11, wherein a reinforcing layer 12 is provided between the inner and outer pipe layers. The inner pipe layer is made of insulating material, the outer pipe layer is made of weather-resistant insulating material, and the reinforcing layer is made of tensile-resistant fiber material. The inner surface of the reinforcing layer is tightly bonded to the outer surface of the inner pipe layer, and the outer surface of the reinforcing layer is tightly bonded to the inner surface of the outer pipe layer. The reinforcing layer has a spiral winding structure along the pipe body axis, and there is an intersection angle between adjacent spiral winding layers. The inner diameter of the inner pipe layer is smaller than the inner diameter of the outer pipe layer, and the thickness of the reinforcing layer accounts for at least two-thirds of the total composite pipe wall thickness.

[0036] In the above technical solution, the spiral winding angle of the reinforcing layer is in the range of 45° to 65° relative to the axial direction of the tube.

[0037] Furthermore, in the above technical solution, the ratio of the thickness of the inner tube layer to the thickness of the reinforcing layer is 1:3 to 1:5.

[0038] Furthermore, in the above technical solution, the reinforcing layer adopts a multi-layer spiral winding structure, and the winding directions of adjacent spiral winding layers 13 are opposite.

[0039] Furthermore, in the above technical solution, the outer surface of the outer tube layer is provided with a number of axially extending ribs 14, which are distributed at equal intervals around the outer circumference of the outer tube layer.

[0040] Furthermore, in the above technical solution, the cross-section of the rib is trapezoidal, the width of the upper base of the trapezoid is smaller than the width of the lower base, and the height of the rib is one-third to one-half of the wall thickness of the outer tube layer.

[0041] Furthermore, in the above technical solution, the inner surface of the inner tube layer is smooth and flat, and the inner tube layer and the reinforcing layer are tightly bonded together by the adhesive layer 15, with the thickness of the adhesive layer being uniformly distributed.

[0042] Furthermore, in the above technical solution, the tensile fiber material of the reinforcing layer is glass fiber or aramid fiber, and the fiber bundles are kept taut during the spiral winding process.

[0043] Furthermore, in the above technical solution, the groove 16 between the ribs on the outer surface of the outer tube layer has an arc-shaped transition structure, and the bottom of the groove forms a smooth connection with the outer surface of the main body of the outer tube layer.

[0044] Furthermore, in the above technical solution, the composite pipe is provided with connecting ends 17 at both ends. The outer diameter of the connecting ends is larger than the outer diameter of the middle section 18 of the pipe body, and the inner diameter of the connecting ends is consistent with the inner diameter of the middle section of the pipe body. The outer surface of the connecting ends is provided with an annular boss 19 for positioning and installation.

[0045] The method of using this utility model is as follows: During the construction of high-voltage transmission lines or cables, firstly, select an appropriate specification of insulating tensile-resistant high-voltage composite pipe according to the span of the line and the expected load. Connect one end of the composite pipe to the fixing device at the starting support point, and use the annular protrusion on the outer surface of the connecting end for positioning to ensure that the axis of the composite pipe is consistent with the laying direction of the transmission line. Then, insert the transmission line or cable into one end of the composite pipe, utilizing the smooth inner surface of the inner pipe layer to reduce the resistance of threading, allowing the line or cable to pass smoothly through the entire pipe body. During the threading process, pay attention to keeping the pipe body straight and avoid excessive bending that could damage the pipe body. After the line or cable has completely passed through, connect and fix the other end of the composite pipe to the fixing device at the end support point. Throughout the laying process, the composite pipe relies on the high tensile strength of its reinforcing layer to withstand the tension generated by its own weight and the weight of the line. The convex rib structure of the outer pipe layer, in conjunction with the support device, provides stable support, ensuring that the pipe body maintains a stable shape under long span conditions. After the composite pipe is installed, its inner and outer layers together provide reliable insulation protection, preventing electrical contact between the transmission line and the external environment. The reinforcing layer continuously withstands various static and dynamic loads, ensuring the long-term safe operation of the line. In daily maintenance, it is only necessary to periodically check whether there is any damage or aging on the outer surface of the composite pipe, and repair or replace any damaged areas as necessary. The entire process is simple and reliable, requiring no complicated maintenance operations.

[0046] The following is a specific embodiment 1 of this utility model: The inner diameter of the insulating tensile high-voltage composite pipe in this embodiment is 100mm, the total wall thickness is 15mm, and the total length is 6000mm. The inner tube layer is made of epoxy resin material through a casting molding process. Epoxy resin has excellent insulation properties and good mechanical strength, with a volume resistivity greater than 10^14 Ω·cm and a breakdown field greater than 20kV / mm. The inner tube layer has a wall thickness of 3mm, and the inner surface is precision-processed to present a smooth and flat state with a surface roughness of less than 1.6μm, which can effectively reduce the frictional resistance of transmission lines or cables during insertion and use. The reinforcing layer uses E-type glass fiber as the tensile fiber material. The linear density of the glass fiber is 2400tex, the single filament diameter is 17μm, the tensile strength is 3400MPa, and the elastic modulus is 72GPa. The reinforcing layer is made by a wet winding process. During the winding process, the glass fiber is impregnated with an epoxy resin matrix, and the fiber volume content is controlled at about 60%. The reinforcing layer employs a four-layer spiral winding structure. The winding angles of the first and third layers are 55°, and the winding angles of the second and fourth layers are -55°, forming a 110° intersection angle between adjacent layers. The total wall thickness of the reinforcing layer is 9mm. During the winding process, a tension control device maintains the tension of the fiber bundles, controlling the tension within the range of 15N~25N to ensure that the fibers are neatly and densely arranged without any looseness. The inner tube layer and the reinforcing layer are bonded together using epoxy resin adhesive. The adhesive layer is approximately 0.2mm thick. After the adhesive is evenly applied, it is cured by heat to form a strong adhesive interface with a bond strength greater than 15MPa. The outer tube layer is made of polyurethane material through a coating molding process. Polyurethane has excellent weather resistance and good insulation properties, with a Shore hardness of 85A, a tensile strength of 35MPa, and an elongation at break of 450%. The outer tube layer has a wall thickness of 3mm. Eight evenly spaced raised ribs are arranged along the axial direction on the outer surface. The cross-section of each rib is trapezoidal, with an upper base width of 8mm, a lower base width of 15mm, and a height of 1.5mm. The circumferential distance between adjacent ribs is 39.25mm. The grooves between the ribs have a rounded transition structure with a radius of 20mm, ensuring a smooth connection between the bottom of the groove and the surface of the outer tube layer. The connecting ends of the composite tube have an outer diameter of 120mm and a length of 150mm. An annular boss with a width of 10mm and a height of 5mm is provided on the outer surface of the connecting end, located in the center of the connecting end, for accurate positioning in conjunction with the positioning groove of the fixing device. The entire composite tube is manufactured in sections and then extended in length using sleeves or flanges. Connecting adjacent sections uses connecting sleeves of the same material, with the inner diameter of the connecting sleeve matching the outer diameter of the composite tube, achieving a secure connection through adhesive bonding or mechanical fastening.In this embodiment, when subjected to axial tensile force, the glass fiber of the reinforcing layer of the composite pipe plays a full role, and the axial tensile strength of the pipe body reaches more than 180MPa, which can withstand various loads generated during long-span overhead laying. The double insulation protection provided by the inner and outer pipe layers enables the power frequency withstand voltage of the composite pipe to reach more than 65kV, which fully meets the insulation requirements of transmission lines with voltage levels of 35kV and below. The weight of the entire composite pipe is only one-fifth of that of a steel pipe of the same specification, which significantly reduces the construction difficulty of overhead laying and the burden on the supporting structure.

[0047] The following is another specific embodiment 2 of this utility model: This embodiment is based on embodiment 1, but the tensile fiber material of the reinforcing layer is changed from E-type glass fiber to aramid fiber. The linear density of the aramid fiber is 1500 tex, the tensile strength is 3000 MPa, the elastic modulus is 130 GPa, and the density is 1.44 g / cm³. 3 Due to its higher specific strength and specific modulus, aramid fiber can provide higher load-bearing capacity under the same wall thickness. Furthermore, aramid fiber exhibits excellent fatigue resistance, making it suitable for withstanding long-term alternating loads. The reinforcing layer still uses a four-layer helical winding structure, but the winding angles are adjusted to 50° and -50°, with a cross angle of 100°. This angle configuration makes the load-bearing capacity of aramid fiber more balanced in the axial and circumferential directions. After adopting aramid fiber, the axial tensile strength of the composite pipe increases to over 240MPa, while the weight is further reduced by approximately 20%. The overall performance of the composite pipe is significantly improved, making it particularly suitable for laying transmission lines in ultra-long spans or high-altitude areas. Under these extreme conditions, the composite pipe needs to withstand greater self-weight loads and wind loads; aramid fiber-reinforced composite pipes provide more reliable safety assurance.

[0048] The following is another specific embodiment 3 of this utility model: This embodiment is based on embodiment 1, with an additional flame-retardant layer added between the outer tube layer and the reinforcing layer. The flame-retardant layer is made of modified epoxy resin material containing a flame retardant, which is a bromine-based or phosphorus-based flame retardant, and the addition amount is 15%~25% of the resin mass. The flame-retardant layer has a wall thickness of 1mm and is formed on the outer surface of the reinforcing layer by coating or wrapping a thin film. The oxygen index of the flame-retardant layer is greater than 28%, and it can self-extinguish when exposed to a fire source and will not continue to burn, effectively improving the fire safety performance of the composite pipe. In order to keep the total wall thickness of the composite pipe unchanged, the wall thickness of the outer tube layer is correspondingly reduced to 2mm. However, since the outer tube layer mainly plays a protective and insulating role, the appropriate reduction in wall thickness does not affect its function. The composite pipe with added flame-retardant layer is particularly suitable for urban cable tunnels, underground integrated pipe corridors, and other occasions with high fire protection requirements. When a fire occurs in an adjacent cable, the flame-retardant layer can prevent the flame from spreading into the interior of the composite pipe, protecting the safety of the transmission lines inside the pipe. At the same time, the flame-retardant gas released by the flame-retardant layer can suppress the spread of the flame, buying valuable time for fire fighting and significantly improving the overall safety of the power system in densely laid environments. In addition to possessing all the excellent performance of Example 1, the composite pipe in this embodiment achieves a higher standard in fire protection performance through the addition of the flame-retardant layer. Combustion tests show that the composite pipe will not undergo penetrating damage within 60 seconds under the action of flame, providing a reliable guarantee for the safe isolation of transmission lines in fire environments.

[0049] The composite pipe manufacturing process of this invention is mature and can be scaled up using continuous production methods, resulting in high production efficiency and controllable costs. The inner tube layer can be manufactured using extrusion molding or casting molding, while the reinforcing layer is manufactured using fiber winding, a process that is highly mature in the composite materials industry, with a high degree of equipment automation and stable product quality. The outer tube layer can be manufactured using extrusion coating or compression molding, and the raised ribs can be formed in one step during extrusion or formed on the surface of the outer tube layer through compression molding. The bonding between the layers employs mature bonding technology, with well-defined technical specifications for adhesive selection and curing condition control. The entire manufacturing process can be monitored online to ensure the consistency and reliability of product performance.

[0050] This invention also boasts excellent scalability, allowing for adjustments and optimizations to the structure and materials to meet diverse application requirements. For higher voltage levels, the thickness of the inner and outer tube layers can be appropriately increased to enhance insulation margin. For applications with larger spans or heavier loads, the number of reinforcing layers can be increased, or stronger fiber materials can be employed to improve load-bearing capacity. In special environments such as high or low temperatures, high-temperature or low-temperature resistant resin matrices and outer materials can be selected to ensure the composite tube maintains good performance even under extreme temperature conditions. For applications requiring special functions, temperature sensing, stress monitoring, and other functional components can be integrated into the composite tube structure to achieve real-time monitoring of its operating status, further improving safety and reliability.

[0051] Specifically, the principle of this invention is as follows: A three-layer composite structure design is adopted, achieving a balance between insulation performance and mechanical strength through optimized material selection and structural design. The inner tube layer uses insulating material, directly contacting the transmission line or cable, providing the first layer of electrical insulation protection. Its smooth inner surface also reduces frictional damage to the line or cable. The reinforcing layer uses tensile fiber material and is manufactured through a spiral winding process. This is the core load-bearing part of the entire composite pipe. The spirally wound fibers form a continuous load-bearing path. When the pipe body is subjected to axial tensile force, the tensile force is converted into tensile stress within the fibers themselves through the fiber's tilt angle, fully utilizing the high tensile strength of the fiber material. By controlling the winding angle within the range of 45° to 65°, the fibers can provide effective load-bearing capacity in both the axial and circumferential directions, achieving multi-directional load-bearing capability. The use of multi-layered reverse staggered winding, with adjacent fiber layers winding in opposite directions, forms a stable network structure. The fibers in different directions constrain each other, effectively suppressing torsional deformation that may occur when the pipe body is under stress, thus improving the overall structural stability. The outer tube layer is made of weather-resistant insulating material, providing protection for the inner reinforcing layer and preventing corrosion of the fibers by environmental factors such as ultraviolet rays, rainwater, and chemicals. Simultaneously, the outer tube layer also serves as a second insulating barrier, further enhancing the insulation safety of the composite pipe. The raised rib structure on the surface of the outer tube layer increases the bending stiffness of the pipe by increasing the moment of inertia, making the pipe less prone to bending and sagging when the span is large. The three-layer structure is tightly bonded through an adhesive layer, eliminating interlayer gaps and allowing each layer to deform collaboratively under stress, preventing structural loosening caused by interlayer slippage. This composite structural design fully utilizes the advantages of each layer's material characteristics: the inner layer provides insulation and a smooth surface, the middle layer provides high strength load-bearing capacity, and the outer layer provides protection and secondary insulation. The three layers work together to form a high-performance overall structure, fundamentally solving the technical challenge of balancing strength and insulation performance in traditional protective pipes.

[0052] In summary, the insulated tensile high-voltage composite pipe provided by this utility model solves the technical problem of balancing insulation performance and mechanical strength in traditional protective pipes through structural improvements and material selection. It achieves a balance of lightweight, high strength, and high insulation performance, providing an effective technical solution for the safe and reliable operation of high-voltage transmission lines and cables.

Claims

1. An insulating, tensile-resistant, high-voltage composite pipe, comprising an inner tube layer and an outer tube layer, characterized in that, A reinforcing layer is provided between the inner tube layer and the outer tube layer; the inner tube layer is made of insulating material, the outer tube layer is made of weather-resistant insulating material, and the reinforcing layer is made of tensile fiber material; the inner surface of the reinforcing layer is tightly bonded to the outer surface of the inner tube layer, and the outer surface of the reinforcing layer is tightly bonded to the inner surface of the outer tube layer; the reinforcing layer has a spiral winding structure along the tube body axis, and there is an intersection angle between adjacent spiral winding layers; the inner diameter of the inner tube layer is smaller than the inner diameter of the outer tube layer, and the thickness of the reinforcing layer accounts for at least two-thirds of the total composite tube wall thickness.

2. The insulating tensile high-voltage composite pipe according to claim 1, characterized in that, The spiral winding angle of the reinforcing layer is in the range of 45° to 65° relative to the axial direction of the tube.

3. The insulating tensile high-voltage composite pipe according to claim 2, characterized in that, The ratio of the thickness of the inner tube layer to the thickness of the reinforcing layer is 1:3 to 1:

5.

4. The insulating tensile high-voltage composite pipe according to claim 3, characterized in that, The reinforcing layer adopts a multi-layer spiral winding structure, with adjacent spiral winding layers winding in opposite directions.

5. The insulating tensile high-voltage composite pipe according to claim 4, characterized in that, The outer surface of the outer tube layer is provided with several axially extending ribs, which are distributed at equal intervals around the outer circumference of the outer tube layer.

6. The insulating tensile high-voltage composite pipe according to claim 5, characterized in that, The cross-section of the rib is trapezoidal, with the upper base width being smaller than the lower base width. The height of the rib is one-third to one-half of the outer tube wall thickness.

7. The insulating tensile high-voltage composite pipe according to claim 6, characterized in that, The inner surface of the inner tube layer is smooth and flat. The inner tube layer and the reinforcing layer are tightly bonded together by an adhesive layer, and the thickness of the adhesive layer is evenly distributed.

8. The insulating tensile high-voltage composite pipe according to claim 7, characterized in that, The tensile fiber material of the reinforcing layer is glass fiber or aramid fiber, and the fiber bundles are kept taut during the spiral winding process.

9. The insulating tensile high-voltage composite pipe according to claim 8, characterized in that, The grooves between the ribs on the outer surface of the outer tube layer have an arc-shaped transition structure, and the bottom of the grooves forms a smooth connection with the outer surface of the main body of the outer tube layer.

10. An insulating tensile high-voltage composite pipe according to claim 9, characterized in that, The composite pipe has connecting ends at both ends. The outer diameter of the connecting ends is larger than the outer diameter of the middle section of the pipe body, and the inner diameter of the connecting ends is consistent with the inner diameter of the middle section of the pipe body. The outer surface of the connecting ends is provided with an annular boss for positioning and installation.

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