Composite pipe and method for manufacturing the same

Abstract

The present invention relates to the field of composite pipes, and discloses a composite pipe and a manufacturing method thereof, wherein the composite pipe comprises: a reinforced thermoplastic plastic pipe, the reinforced thermoplastic plastic pipe having a plastic core pipe layer (1) and a belt-type reinforcement layer (2) coated on the outer periphery of the plastic core pipe layer (1); a foamed plastic protective layer (4), the foamed plastic protective layer (4) coated on the outer periphery of the reinforced thermoplastic plastic pipe; a polyester film layer (5), the polyester film layer (5) coated on the outer side of the foamed plastic protective layer (4); and a plastic outer protective layer (6), the plastic outer protective layer (6) being separated from the foamed plastic protective layer (4) by the polyester film layer (5). The composite pipe of the present invention coats the outer periphery of the reinforced thermoplastic plastic pipe with a foamed plastic protective layer, thereby utilizing the buffering effect generated by the void structure of the foamed plastic protective layer to reduce the damage to the belt-type reinforcement layer caused by external effects such as construction impact.

Description

Technical Field

[0001] The present invention relates to a composite pipe, and in particular to a method for manufacturing the composite pipe. In addition, the present invention also relates to a composite pipe. Background Art

[0002] Reinforced Thermoplastic Pipes (RTP pipes) are high-performance pipes that significantly improve mechanical strength and compressive strength by adding reinforcing materials (such as glass fiber, carbon fiber, aramid fiber, etc.) to the thermoplastic matrix. In traditional technology, RTP pipes are mainly used in the oil and gas industry.

[0003] Generally, the main goal of RTP pipes is to improve their ability to resist internal pressure. To this end, by adding the above-mentioned high-performance fiber materials, they can be used to transport fluids that generate large internal pressure. With the development of market demand, the ability of RTP pipes to resist external loads such as external pressure has also attracted attention in some application fields. For example, in response to the axial tension conditions such as the impact of waves in the marine environment and the vertical downward gravity of the downhole pipe, Chinese invention patent application CN115609981A provides a composite pipe with a core tube coated with a metal corrugated protective layer on the outside, and its manufacturing method and production equipment. During the manufacturing process, first, a trimming machine is used to cut off the two sides of the steel strip raw material released by the steel strip unwinder to eliminate the uneven or oxidized edges and other defective parts on both sides of the width of the steel strip raw material, and obtain a steel strip with a width suitable for coating the outer circumference of the core tube; then, the steel strip is bent by a steel strip cold bending forming unit and coated on the outside of the core tube; then, a longitudinal welding device is used to weld the longitudinal seam of the steel strip coated on the outside of the core tube along the axial direction of the core tube; finally, a corrugator is used to corrugate the outside of the steel strip so that the steel strip is formed into a metal corrugated protective layer. In addition, the manufacturing process may also include: a step of setting a sliding layer on the outside of the core pipe before coating the metal corrugated protective layer, a step of coating, winding an anti-corrosion layer and extruding a plastic outer protective layer on the outside of the metal corrugated protective layer after coating the metal corrugated protective layer, and a step of rolling up the formed composite pipe.

[0004] The above-mentioned prior art can significantly improve the adaptability of the coilable RTP pipe to the harsh external environment. In particular, since the steel strip coated on the outside of the core pipe is continuous in the axial direction of the core pipe, it can also withstand the axial tension such as the vertical downward gravity when used as a downhole pipe. However, since operations such as longitudinal welding and corrugation are required, this seriously restricts the improvement of production efficiency. Summary of the invention

[0005] The object of the present invention is to provide a new composite pipe and a method for manufacturing the same, which can effectively prevent the belt-type reinforcement layer (especially glass fiber reinforcement material) from being damaged due to external effects such as construction impact, and facilitates efficient production.

[0006] In order to achieve the above object, the present invention provides a method for manufacturing a composite pipe, comprising the following steps:

[0007] S1. Providing a reinforced thermoplastic pipe, the reinforced thermoplastic pipe having a plastic core tube layer and a belt-type reinforcement layer coated on the periphery of the plastic core tube layer;

[0008] S2. The foamed plastic tape is spirally wrapped around the outer circumference of the reinforced thermoplastic tube to form a foamed plastic protective layer;

[0009] S3. The polyester film is spirally wrapped around the outer side of the foam plastic protective layer to form a polyester film layer;

[0010] S4. Extruding an outer protective layer of plastic toward the outer side of the polyester film layer to form a plastic outer protective layer.

[0011] Preferably, step S1 comprises:

[0012] S11. The plastic core tube extruder having an annular die is used to extrude the plastic core tube raw material, and the plastic core tube layer is formed by cooling and shaping;

[0013] S12. Helically wind one or more layers of glass fiber reinforced tape on the outer circumference of the plastic core tube layer to form the tape-type reinforced layer that completely covers the outer circumference of the plastic core tube layer.

[0014] Preferably, in step S12, each layer of the glass fiber reinforced tape is bonded to the inner plastic core tube layer or an adjacent layer of the glass fiber reinforced tape by heating in an oven.

[0015] Preferably, step S1 comprises: extruding a plastic outer layer raw material toward the outer side of the belt-type reinforcement layer to form a plastic outer layer.

[0016] Preferably, in step S2, the foamed plastic protective layer is formed by spirally winding the foamed plastic tape around the outer circumferential surface of the reinforced thermoplastic plastic tube; and / or, in step S3, the polyester film layer is formed by spirally winding a polyester film tape around the outside of the foamed plastic protective layer.

[0017] Preferably, the foamed plastic belt is EVA foam, and the polyester film is a polyester film.

[0018] A second aspect of the present invention provides a composite pipe, comprising:

[0019] A reinforced thermoplastic plastic pipe, the reinforced thermoplastic plastic pipe comprising a plastic core pipe layer and a belt-type reinforcement layer covering the outer periphery of the plastic core pipe layer;

[0020] A foamed plastic protective layer, the foamed plastic protective layer is coated on the outer circumference of the reinforced thermoplastic plastic tube;

[0021] a polyester film layer, the polyester film layer being coated on the outer side of the foamed plastic protective layer; and

[0022] A plastic outer protective layer is separated from the foamed plastic protective layer by the polyester film layer.

[0023] Preferably, the thickness of the foamed plastic protective layer is 5 mm-50 mm.

[0024] Preferably, the reinforced thermoplastic plastic pipe further comprises a plastic outer layer covering the outer circumference of the belt-type reinforcement layer.

[0025] Preferably, the foamed plastic protective layer is formed by spirally winding EVA foam around the outer circumference of the reinforced thermoplastic plastic tube, and the polyester film layer is formed by spirally winding a polyester film around the outer side of the foamed plastic protective layer (4).

[0026] Through the above technical solution, by coating the outer periphery of the reinforced thermoplastic plastic pipe with a foamed plastic protective layer, the buffering effect generated by the void structure of the foamed plastic protective layer can be utilized to reduce the damage to the belt-type reinforcement layer caused by external effects such as construction impact. The polyester film layer arranged between the foamed plastic protective layer and the plastic outer protective layer can not only fix the coated foamed plastic belt, but also allow the plastic outer protective layer to have a sliding freedom relative to the internal layers, so as to reduce the risk of stress brittle fracture of the belt-type reinforcement layer during the winding and laying of the composite pipe. Compared with the metal corrugated protective layer formed by cold bending, longitudinal welding and corrugation processes used in the prior art, the present invention can form a foamed plastic protective layer by spiral winding and other methods, thereby allowing the axial running speed of the pipe to be greatly increased during manufacturing to improve production efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 is a cross-sectional view of a pipe wall of a composite pipe according to a preferred embodiment of the present invention;

[0028] Figure 2 FIG. 4 is a cross-sectional view of a composite pipe according to another preferred embodiment of the present invention.

[0029] Description of Reference Numerals

[0030] 1- plastic core tube layer; 2- belt reinforcement layer; 3- plastic outer layer; 4- foamed plastic protective layer; 5- polyester film layer; 6- plastic outer protective layer. DETAILED DESCRIPTION

[0031] The specific implementation of the present invention is described in detail below in conjunction with the accompanying drawings. It should be understood that the specific implementation described here is only used to illustrate and explain the present invention, and is not used to limit the present invention.

[0032] The present invention provides a manufacturing method of a composite pipe and a composite pipe that can be manufactured by the manufacturing method. The composite pipe forms a foamed plastic protective layer by coating a foamed plastic belt on the outer periphery of a reinforced thermoplastic plastic pipe, thereby significantly improving its adaptability to external effects such as construction impact. Compared with the composite pipe coated with a metal corrugated protective layer and the manufacturing method thereof in the prior art, the present invention utilizes the buffering effect generated by the void structure of the foamed plastic protective layer to reduce the damage to the belt-type reinforcement layer caused by external effects such as construction impact, and can be efficiently produced. It is understandable that the relevant steps proposed in CN115609981A (such as the steps of manufacturing the core pipe, the steps of extruding the plastic outer protective layer and the winding step, etc.) are also applicable to the manufacturing method of the present invention, so the steps of forming the foamed plastic protective layer and the polyester film layer and the foamed plastic belt and polyester film used will be described in detail below.

[0033] Reference Figure 1 As shown, according to a preferred embodiment of the present invention, the composite pipe comprises a reinforced thermoplastic pipe, a foamed plastic protective layer 4, a polyester film layer 5 and a plastic outer protective layer 6 arranged in sequence from the inside to the outside, wherein the reinforced thermoplastic pipe comprises a plastic core pipe layer 1 and a belt-type reinforcement layer 2 coated on the outer periphery of the plastic core pipe layer 1, the foamed plastic protective layer 4 is coated on the outer periphery of the reinforced thermoplastic pipe, and the polyester film layer 5 is coated on the outer side of the foamed plastic protective layer 4 and separates the foamed plastic protective layer 4 from the plastic outer protective layer 6. Thus, when an external force impact such as violent construction occurs, the foamed plastic protective layer 4 can protect the belt-type reinforcement layer 2 in the reinforced thermoplastic pipe from damage, thereby improving the ability of the composite pipe to resist external impact. The belt-type reinforcement layer 2 can be a reinforcing tape such as glass fiber, carbon fiber, aramid fiber, etc. coated on the outer periphery of the plastic core pipe layer 1, and the reinforced thermoplastic pipe can have one or more layers of reinforcing tape. For example, the belt-type reinforcement layer 2 formed of a glass fiber reinforced tape is prone to breakage when the composite pipe is subjected to external impact and rolled up with a small inner diameter, which seriously damages the reinforcement effect of the belt-type reinforcement layer 2. By coating the outer surface of the belt-type reinforcement layer with a foamed plastic protective layer 4, the environmental adaptability and service life of the composite pipe can be effectively improved.

[0034] Therefore, the composite pipe of the present invention utilizes the buffering effect generated by the void structure of the foamed plastic protective layer 4 to reduce the damage to the belt-type reinforcement layer 2 (such as glass fiber reinforced tape) caused by external effects such as construction impact. It can be formed by coating the foamed plastic tape on the outer periphery of the reinforced thermoplastic plastic pipe, and should have a certain degree of foaming and thickness. For example, the thickness of the foamed plastic protective layer 4 can be 5mm-50mm, thereby providing relatively sufficient protection for the inner belt-type reinforcement layer 2 and facilitating the coiling of the prepared composite pipe. In a preferred embodiment, the foamed plastic tape can be a relatively hard type with a porous structure, so that it can be coated on the outer surface of the belt-type reinforcement layer 2 after cooling and setting by spiral winding. For example, the foamed plastic tape can be selected as EVA foam. In other embodiments, the foamed plastic tape can also be coated on the outer surface of the belt-type reinforcement layer 2 by other methods such as longitudinal curling.

[0035] The polyester film layer 5 disposed between the foamed plastic protective layer 4 and the plastic outer protective layer 6 can not only fix the coated foamed plastic belt, but also allow the plastic outer protective layer 6 to have a sliding freedom relative to the internal layers, so as to reduce the risk of stress brittle fracture of the belt-type reinforcement layer 2 and the like during the winding, unwinding and laying of the composite pipe. For the reelable composite pipe, this sliding freedom is significantly beneficial for the case of reeling with a smaller diameter. In addition, the composite pipe may also need the above-mentioned sliding freedom due to bending and stretching during the laying, storage and transportation process. The polyester film layer 5 can be formed by spirally winding a polyester film, which can be specifically selected as a polyester film or other suitable materials.

[0036] The production process of the composite pipe does not require processes such as welding and corrugating. It only requires the foamed plastic protective layer 4 and the polyester film layer 5 to be coated on the periphery of the outer periphery of the reinforced thermoplastic plastic pipe. Since there is no limitation on the process speed such as longitudinal welding and corrugating, the axial running speed of the pipe can be greatly increased during manufacturing, thereby effectively improving production efficiency.

[0037] Figure 2 A cross-sectional view of a composite pipe according to another preferred embodiment is shown. Figure 1 In the embodiment shown, the composite pipe further comprises a plastic outer layer 3 covering the outer periphery of the belt-type reinforcement layer 2. As mentioned above, the molding steps of the plastic outer layer 3 and the like can be performed by extrusion, heating and cooling to shape using the same equipment and process as proposed in CN115609981A.

[0038] Compared with the metal corrugated protective layer, the present invention uses a foamed plastic protective layer to protect the belt-type reinforcement layer, which reduces the ability to withstand axial tension. However, for scenarios such as underground construction where there is no axial tension requirement, the composite pipe of the present invention can effectively reduce the damage to the belt-type reinforcement layer caused by external impacts such as violent construction, and allow the use of a relatively high axial running speed of the pipe, thereby significantly improving the production efficiency of the composite pipe with an outer protective layer.

[0039] The following is an explanation of the manufacturing method of the composite pipe provided by the present invention, which can be used to manufacture the aforementioned composite pipe. The molding process of the plastic core tube layer 1, the belt-type reinforcement layer 2, the plastic outer layer 3 (if any) and the plastic outer protective layer 6 can adopt the equipment and process provided by the prior art. The manufacturing method of the present invention comprises the following steps:

[0040] S1. Provide a reinforced thermoplastic plastic pipe, which has a plastic core tube layer 1 and a belt-type reinforcement layer 2 wrapped around the outer periphery of the plastic core tube layer 1; S2. Wrap a foamed plastic belt around the outer periphery of the reinforced thermoplastic plastic pipe to form a foamed plastic protective layer 4; S3. Wrap a polyester film around the outer side of the foamed plastic protective layer 4 to form a polyester film layer 5; S4. Extrude an outer protective layer plastic to the outer side of the polyester film layer 5 to form a plastic outer protective layer 6.

[0041] Compared with the metal corrugated protective layer formed by cold bending, longitudinal welding and corrugation processes used in the prior art, the present invention can form a foamed plastic protective layer by spiral winding, etc., thereby allowing the axial running speed of the pipe to be greatly improved during manufacturing to improve production efficiency.

[0042] The above step S1 may include the following sub-steps:

[0043] S11. Using a plastic core tube extruder with an annular die head to extrude the plastic core tube raw material, and cooling and shaping to form a plastic core tube layer 1; S12. Helically winding one or more layers of glass fiber reinforced tape on the outer peripheral surface of the plastic core tube layer 1, and forming a tape-type reinforced layer 2 that completely covers the outer peripheral surface of the plastic core tube layer 1. In step S12, after each layer of glass fiber reinforced tape is wound on the plastic core tube layer 1, it can be heated in an oven to make it bonded to the outer peripheral surface of the plastic core tube layer 1 inside it or an adjacent layer of glass fiber reinforced tape, and fixed together by means such as air cooling.

[0044] Furthermore, the above step S1 may also include a sub-step of forming the plastic outer layer 3 : the plastic outer layer 3 is formed by extruding the plastic outer layer raw material toward the outside of the belt-type reinforcement layer 2 .

[0045] In the above step S2, a foamed plastic protective layer 4 can be formed by spirally winding a foamed plastic strip, such as EVA foam, on the outer peripheral surface of a reinforced thermoplastic plastic tube; in the above step S3, a polyester film layer 5 can be formed by spirally winding a polyester film strip, such as polyester film, on the outer side of the foamed plastic protective layer 4.

[0046] The preferred embodiments of the present invention are described in detail above in conjunction with the accompanying drawings, but the present invention is not limited thereto. Within the technical concept of the present invention, the technical solution of the present invention can be subjected to a variety of simple modifications, including the combination of various specific technical features in any suitable manner. In order to avoid unnecessary repetition, the present invention will not further describe various possible combinations. However, these simple modifications and combinations should also be regarded as the contents disclosed by the present invention and belong to the protection scope of the present invention.

Claims

1. A method for manufacturing a composite pipe, characterized in that: The steps include: S1. Providing a reinforced thermoplastic plastic pipe, the reinforced thermoplastic plastic pipe having a plastic core tube layer (1) and a belt-type reinforcement layer (2) coated on the outer periphery of the plastic core tube layer (1); S2. Wrapping the foamed plastic tape around the outer periphery of the reinforced thermoplastic tube to form a foamed plastic protective layer (4); S3. The polyester film is coated on the outer side of the foam plastic protective layer (4) to form a polyester film layer (5); S4. Extruding an outer protective layer of plastic toward the outside of the polyester film layer (5) to form a plastic outer protective layer (6).

2. The method for manufacturing a composite pipe according to claim 1, characterized in that: Step S1 includes: S11. The plastic core tube raw material is extruded by a plastic core tube extruder having an annular die head, and the plastic core tube layer (1) is formed by cooling and shaping; S12. Helically wind one or more layers of glass fiber reinforced tape onto the outer circumference of the plastic core tube layer (1) to form the tape-type reinforced layer (2) that completely covers the outer circumference of the plastic core tube layer (1).

3. The method for manufacturing a composite pipe according to claim 2, characterized in that: In step S12, each layer of the glass fiber reinforced tape is bonded to the inner plastic core tube layer (1) or an adjacent layer of the glass fiber reinforced tape by heating in an oven.

4. The method for manufacturing a composite pipe according to claim 1, characterized in that: Step S1 comprises: extruding a plastic outer layer raw material toward the outer side of the belt-type reinforcement layer (2) to form a plastic outer layer (3).

5. The method for manufacturing a composite pipe according to claim 1, characterized in that: In step S2, the foamed plastic protective layer (4) is formed by spirally winding the foamed plastic tape around the outer circumference of the reinforced thermoplastic plastic tube; and / or, in step S3, the polyester film layer (5) is formed by spirally winding a polyester film tape around the outer side of the foamed plastic protective layer (4).

6. The method for manufacturing a composite pipe according to claim 1, characterized in that: The foamed plastic belt is EVA foam, and the polyester film is a polyester film.

7. A composite pipe, characterized in that: include: A reinforced thermoplastic plastic pipe, comprising a plastic core pipe layer (1) and a belt-type reinforcement layer (2) covering the outer periphery of the plastic core pipe layer (1); A foamed plastic protective layer (4), the foamed plastic protective layer (4) covering the outer circumference of the reinforced thermoplastic plastic tube; a polyester film layer (5), the polyester film layer (5) being coated on the outer side of the foamed plastic protective layer (4); and A plastic outer protective layer (6), the plastic outer protective layer (6) is separated from the foamed plastic protective layer (4) by the polyester film layer (5).

8. The composite pipe according to claim 7, characterized in that: The thickness of the foamed plastic protective layer (4) is 5 mm-50 mm.

9. The composite pipe according to claim 7, characterized in that: The reinforced thermoplastic plastic pipe also has a plastic outer layer (3) covering the outer periphery of the belt-type reinforcement layer (2).

10. The composite pipe according to claim 7, characterized in that: The foamed plastic protective layer (4) is formed by spirally winding EVA foam around the outer circumference of the reinforced thermoplastic plastic tube, and the polyester film layer (5) is formed by spirally winding a polyester film around the outer side of the foamed plastic protective layer (4).

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