Composite pipe and method of making same

Abstract

The application discloses a kind of composite pipe and its manufacturing method, it is related to composite pipe technical field, it solves the problem that the ring stiffness, pressure capacity and structural stability of existing composite pipe cannot meet the requirements synchronously, improve production quality and production efficiency, specific scheme is as follows: including from inside to outside sequentially arranged high polymer inner tube, composite reinforcing layer, high polymer outer protective layer and structure wall, the high polymer inner tube is extrusion formed, composite reinforcing layer is formed by several layers of reinforcing material left and right cross spiral winding, composite reinforcing layer is fixedly connected with high polymer inner tube, high polymer outer protective layer, the structure wall is spirally wound and fixed on high polymer outer protective layer to increase the ring stiffness of pipe, and the structure wall is tubular structure.

Description

Technical Field

[0001] This invention relates to the field of composite pipe technology, and in particular to a composite pipe and its manufacturing method. Background Technology

[0002] Currently, the largest composite pipe on the market, such as steel wire mesh reinforced polyethylene composite pipe, is DN1200. Larger diameter pipes result in high production equipment costs and low ring stiffness. Increasing ring stiffness requires thicker pipe walls, further increasing production costs. Therefore, PCCP or ductile iron pipes are commonly used. However, these products are prone to water pollution with long-term use, have short lifespans, and high overall operating costs. While high-density polyethylene (HDPE) spiral wound structured pipes meet ring stiffness requirements, they have low pressure resistance, limited application range, and the sheet-winding method for the inner pipe can lead to poor interlayer bonding and defects such as pores in the inner wall. High precision control of the production process is required, and the long cooling time results in discontinuous production and low production capacity. Summary of the Invention

[0003] To address the shortcomings of existing technologies, the present invention aims to provide a composite pipe and its manufacturing method. A composite reinforcing layer is provided on the outside of the polymer inner tube to improve the overall strength of the pipe, reducing the wall thickness of large-diameter plastic pipes under the same pressure. A tubular structural wall is wound on the polymer outer sheath to improve the ring stiffness of large-diameter plastic pipes. This solves the problem that existing composite pipes cannot simultaneously meet the requirements for ring stiffness, pressure bearing capacity and structural stability.

[0004] To achieve the above objectives, the present invention is implemented through the following technical solution:

[0005] In a first aspect, the present invention provides a composite pipe comprising, from the inside out, a polymer inner tube, a composite reinforcing layer, a polymer outer sheath, and a structural wall. The polymer inner tube is extruded and formed. The composite reinforcing layer is formed by spirally winding several layers of reinforcing materials in a crisscross pattern. The composite reinforcing layer is fixedly connected to the polymer inner tube and the polymer outer sheath. The structural wall is spirally wound and fixed on the polymer outer sheath to increase the ring stiffness of the pipe. The structural wall has a tubular structure.

[0006] As a further implementation, the polymer inner tube is individually extruded from polyethylene material.

[0007] As a further implementation, the composite reinforcing layer is fixedly connected to the polymer inner tube and the polymer outer sheath by an adhesive material.

[0008] As a further implementation, the reinforcing material can be any one or more combinations of materials such as fiberglass tape, carbon fiber tape, steel chain rope, and steel wire.

[0009] As a further implementation, the winding angle of the reinforcing material is 45°-75°.

[0010] Secondly, the present invention provides a method for manufacturing composite pipes, as detailed below:

[0011] The polymer inner tube is produced separately and then cooled, shaped, and cut.

[0012] The inner polymer tube is supported and then placed on a conveyor line for spiral transport.

[0013] The polymer inner tube on the conveyor line is heated and several layers of reinforcing material are spirally wound around its surface in a crisscross pattern.

[0014] After the reinforcing material is wound, a polymer outer sheath is wound, and then the structural wall is wound on the polymer outer sheath.

[0015] Remove the internal supports of the pipe and perform pipe cooling, cutting, and joint processing.

[0016] As a further implementation, the conveyor line is a rotating roller structure with a set angle, which is composed of several rotating roller groups, each rotating roller group containing two rotating rollers arranged opposite each other.

[0017] As a further implementation, the reinforcing material needs to be heated before winding, and the reinforcing material is impregnated with a binder material before composite.

[0018] As a further implementation, the polyethylene sheet is compacted using rollers located below the pipe during the polyethylene sheet winding process.

[0019] As a further implementation, the winding process of the structural wall and the winding process of the composite reinforcement layer are carried out simultaneously.

[0020] The beneficial effects of the present invention are as follows:

[0021] (1) The present invention uses polymer inner tube extrusion molding to avoid problems such as poor interlayer bonding and inner wall pores caused by poor control of winding process. A composite reinforcing layer is set on the outside of the polymer inner tube to improve the overall strength of the tube, reduce the wall thickness of large-diameter plastic tubes under the same pressure, and a tubular structural wall is wound on the polymer outer protective layer to improve the ring stiffness of large-diameter plastic tubes and improve the production quality of composite tubes.

[0022] (2) The polymer inner tube of the present invention is independently extruded and molded. The composite work of the polymer inner tube and the production work of the polymer inner tube do not affect each other, which greatly ensures the continuity of pipe production and improves production efficiency.

[0023] (3) The pre-wetting treatment of the reinforcing material of the present invention eliminates the need to coat the surface of the polymer inner tube with adhesive material during the winding process, which not only improves production efficiency but also ensures the uniformity of the coating of adhesive material on both the inner and outer sides of the composite reinforcing layer.

[0024] (4) In the process of winding polyethylene sheet, the present invention uses the roller below the pipe to compact the polyethylene sheet, so that the polyethylene sheet and the composite reinforcement layer are tightly connected together, ensuring the tightness of the bonding between the pipe layers and avoiding the generation of air holes in the inner wall.

[0025] (5) The winding process of the structural wall and the winding process of the composite reinforcement layer are carried out simultaneously in this invention. There is no need to preheat the composite reinforcement layer or the structural wall, which simplifies the production steps, reduces the production time, and greatly improves the production efficiency. Attached Figure Description

[0026] The accompanying drawings, which form part of this invention, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an improper limitation of the invention.

[0027] Figure 1 This is a structural schematic diagram of a composite pipe according to one or more embodiments of the present invention;

[0028] In the diagram: the spacing or dimensions between parts have been exaggerated to show their positions; the diagram is for illustrative purposes only.

[0029] The components include: 1. Polymer inner tube; 2. Adhesive material; 3. Composite reinforcement layer; 4. Polymer outer protective layer; and 5. Structural wall. Detailed Implementation

[0030] It should be noted that the following detailed description is illustrative and intended to provide further explanation of the invention. Unless otherwise specified, all technical and scientific terms used in this invention have the same meaning as commonly understood by one of ordinary skill in the art to which this invention pertains.

[0031] As described in the background section, the largest commercially available steel wire mesh reinforced polyethylene composite pipe is DN1200. Larger diameters result in high production equipment costs and low pipe ring stiffness. Increasing ring stiffness requires increasing pipe wall thickness, further raising production costs. While high-density polyethylene (HDPE) spiral wound pipes meet ring stiffness requirements, they suffer from low pressure resistance, limited application range, and the sheet-winding method for the inner pipe can lead to poor interlayer bonding and pores in the inner wall. Furthermore, the long cooling time results in discontinuous production and low capacity. To address these technical problems, this invention proposes a composite pipe and its manufacturing method.

[0032] Example 1

[0033] In a typical embodiment of the present invention, such as Figure 1 As shown, a composite pipe is proposed, comprising, from the inside out, a polymer inner pipe 1, a composite reinforcing layer 3, a polymer outer protective layer 4, and a structural wall 5.

[0034] The composite reinforcing layer 3 is fixedly connected to the polymer inner tube 1 and the polymer outer protective layer 4 on its inner and outer sides by an adhesive material 2.

[0035] The polymer inner tube 1 is formed by melting and extruding polyethylene particles and then cutting it. It is used to transport fluids. The polymer inner tube 1 is extruded separately, which can avoid problems such as poor interlayer bonding and inner wall porosity caused by poor control of the winding process. At the same time, it can effectively avoid the problem of low production efficiency caused by excessive cooling time of the tube.

[0036] The composite reinforcement layer 3 is composed of several layers of reinforcing materials that are spirally wound in a crisscross pattern. The reinforcing materials can be any one or more of the following materials: fiberglass tape, carbon fiber tape, steel chain rope, steel wire, etc. The winding angle is between 45° and 75°.

[0037] The addition of composite reinforcement layer 3 significantly reduces the wall thickness of large-diameter plastic pipes under the same pressure, thereby reducing material and production costs.

[0038] It is understandable that the specific number of composite reinforcement layers 3 is determined according to actual design requirements, and no further restrictions are imposed here.

[0039] The polymer outer sheath 4 is made of polyethylene sheet extruded by an extruder and wound around the outside of the composite reinforcement layer 3.

[0040] A structural wall 5 is wound and fixed on the outside of the polymer outer sheath 4. The structural wall 5 mainly serves as a reinforcing rib to improve the ring stiffness of the large-diameter plastic pipe. The structural wall 5 is a tubular structure and is spirally wound along the outer wall of the pipe (i.e., the polymer outer sheath 4). In this embodiment, the structural wall 5 is made of polyethylene material.

[0041] The installation of structural wall 5 greatly improves the ring stiffness of large-diameter plastic pipes and effectively prevents pipe deformation.

[0042] It is understood that the structural wall 5 can also be a multi-layered tubular structure. In this case, each layer is made of a different material, such as polypropylene or polyethylene. In other embodiments, the structural wall 5 can also be other structures. The specific structural type is not restricted here, as long as it can ensure that it has the ability to improve the ring stiffness of large-diameter plastic pipes.

[0043] Example 2

[0044] In a typical embodiment of the present invention, a method for manufacturing the composite pipe described in Example 1 is provided, as follows:

[0045] First, the polymer inner tube 1 is prepared:

[0046] The polymer inner tube 1 is produced separately using a conventional PE pipe production line. Specifically, the raw materials are mixed and dried, polyethylene granules are melt-extruded and molded, and then cooled and shaped in a vacuum sizing box.

[0047] The cooled and formed tube is pulled by a traction machine and cut to a specified length to obtain a polymer inner tube 1 of a set size.

[0048] Since the polymer inner tube 1 is extruded and produced independently, the composite work of the cut polymer inner tube 1 does not affect the production work of the polymer inner tube 1, which can ensure the continuity of pipe production and improve production efficiency.

[0049] The interior of the polymer inner tube 1 is supported, and the polymer inner tube 1 containing the internal support is placed on the conveyor line. The conveyor line is a rotating roller structure with a set angle, which can drive the polymer inner tube 1 to rotate and move around the axis to realize the spiral conveying of the polymer inner tube 1.

[0050] Specifically, an internal support device is installed inside the cut polymer inner tube 1. The internal support device can ensure that the polymer inner tube 1 will not deform during the conveying and winding process. The polymer inner tube 1 with the internal support device is placed on the conveying line so that the axis of the polymer inner tube 1 is the same as the axis of the rotating support roller.

[0051] The conveyor line is composed of several rotating roller groups. Each rotating roller group contains two rotating rollers arranged opposite each other. The two rotating rollers have the same axis and the axis is the same as the conveying direction. The space between the two rotating rollers is used to place the polymer inner tube 1. Several rotating roller groups are arranged at intervals along the conveying direction.

[0052] It is understandable that the internal support device can be a telescopic support frame structure or a support mold structure with the same outer diameter as the inner diameter of the polymer inner tube 1. The internal support device can be selected according to actual needs.

[0053] The polymer inner tube 1 containing the internal support device is heated, and several layers of reinforcing material are spirally wound in a crisscross pattern on the outer surface of the polymer inner tube 1 to finally form a composite reinforcing layer 3 on the outer wall of the polymer inner tube 1.

[0054] The reinforcing material needs to be heated before winding, and the reinforcing material is processed by impregnation, that is, the reinforcing material is impregnated in the adhesive material 2, so that the surface of the reinforcing material contains the adhesive material 2 before the composite.

[0055] Pre-impregnation of the reinforcing material eliminates the need to coat the surface of the polymer inner tube 1 with adhesive material 2 during the winding process. This not only improves production efficiency but also ensures the uniformity of the coating of adhesive material 2 on both the inner and outer sides of the composite reinforcing layer 3.

[0056] After the composite reinforcing layer 3 is wound, the polymer outer protective layer 4 is wound.

[0057] Specifically, a polyethylene sheet is extruded using an extruder and wound onto the outer surface of the composite reinforcing layer 3. Simultaneously, during the winding process, rollers below the pipe are used to compact the polyethylene sheet, ensuring a tight bond between the polyethylene sheet and the composite reinforcing layer 3. This guarantees the tightness of the interlayer bonding and prevents the formation of pores on the inner wall.

[0058] Structural walls 5 are wound around the polymer outer protective layer 4;

[0059] Specifically, the structural wall 5 is a tubular structure. The structural wall 5 is extruded by an extruder and then vacuum cooled and shaped in a vacuum cooling box. After cooling and shaping, the structural wall 5 is spirally wound onto the polymer outer protective layer 4 under the action of a traction machine for composite formation.

[0060] The winding process of the structural wall 5 and the winding process of the composite reinforcement layer 3 are carried out simultaneously to ensure that the structural wall 5 and the composite reinforcement layer 3 are effectively connected together.

[0061] Since the composite reinforcing layer 3, the polymer outer protective layer 4, and the structural wall 5 are all composited by rotating the pipe, the volume of the composite equipment can be effectively reduced, greatly reducing the processing difficulty and operating cost of the equipment. In addition, each structural layer of the pipe is prepared independently, which effectively ensures the continuity of production.

[0062] After the structural wall 5 is wound, the pipe is cooled, cut, and the joints are processed.

[0063] Specifically, the pipes are cooled by spray cooling, the internal support device is removed, and the pipes are cut and processed according to the design length to obtain compliant pipes that meet the requirements and are then inspected and put into storage.

[0064] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A method for manufacturing a composite pipe, characterized in that, Includes the following steps: The polymer inner tube is produced separately and then cooled, shaped, and cut. The polymer inner tube is supported inside and then placed on a conveyor line for spiral conveying; the conveyor line is a rotating roller structure with a set angle, which is composed of several rotating roller groups, each of which contains two rotating rollers arranged opposite each other. The polymer inner tube on the conveyor line is heated and several layers of reinforcing material are spirally wound around its surface in a crisscross pattern to form a composite reinforcing layer; the reinforcing material needs to be heated before winding and impregnated with a bonding material before composite formation; After the reinforcing material is wound, a polymer outer sheath is wound, and then the structural wall is wound on the polymer outer sheath. The polyethylene sheet is extruded using an extruder and wound onto the outer surface of the composite reinforcement layer to form a polymer outer protective layer; during the winding process, the polyethylene sheet is compacted using rollers below the pipe. The winding process of the structural wall and the winding process of the composite reinforcement layer are carried out simultaneously; Remove the internal supports of the pipe and perform pipe cooling, cutting, and joint processing.

2. The method for manufacturing a composite pipe according to claim 1, characterized in that, The polymer inner tube is formed by extrusion molding of polyethylene material alone.

3. The method for manufacturing a composite pipe according to claim 1, characterized in that, The composite reinforcing layer is fixedly connected to the polymer inner tube and the polymer outer sheath by adhesive materials.

4. The method for manufacturing a composite pipe according to claim 1, characterized in that, The reinforcing material is any one or a combination of fiberglass tape, carbon fiber tape, steel chain rope, and steel wire.

5. The method for manufacturing a composite pipe according to claim 1, characterized in that, The winding angle of the reinforcing material is 45°-75°.

6. The composite pipe obtained by the manufacturing method according to any one of claims 1-5, characterized in that, It includes a polymer inner tube, a composite reinforcement layer, a polymer outer sheath, and a structural wall arranged sequentially from the inside out; the polymer inner tube is extruded and formed, the composite reinforcement layer is formed by several layers of reinforcement material spirally wound in a crisscross pattern, the composite reinforcement layer is fixedly connected to the polymer inner tube and the polymer outer sheath, and the structural wall is spirally wound and fixed on the polymer outer sheath to increase the ring stiffness of the tube, and the structural wall is a tubular structure.

Images