A composite pipe joint assembly

Abstract

The application discloses a composite material pipe interface assembly which comprises an inner component, an outer component and a sealing ring. The inner component is a conical tubular part which is provided with an annular protrusion, an outer thread and a torque applying part on its outer wall; the outer component is a cylindrical part which is provided with a high roughness surface section, an annular flange surface, the sealing ring and a slotted groove on its outer wall, and an inner thread on its inner wall. The assembly can be inserted into the end interface of a composite material pipe and torque is applied by the inner component to make the outer component expand radially outward, so as to increase the fitting degree and friction with the composite material pipe and ensure firm connection. The assembly also extrudes the sealing ring to ensure the air tightness of the connection and prevent gas leakage. The assembly can also realize the contraction of the outer component through the reset ring of the inner component, so as to facilitate disassembly and replacement. The composite material pipe interface assembly has the advantages of quick installation, firm connection and good air tightness.

Description

Technical Field

[0001] This invention belongs to the field of pipeline connection technology, particularly the field of composite material pipeline connection technology, and relates to a pipeline interface assembly, specifically a composite material pipeline interface assembly. This invention can be widely applied in various applications requiring composite material pipelines, such as petroleum, chemical, aviation, aerospace, and compressed air energy storage. The composite material pipeline interface assembly of this invention meets the requirements for safe application under high pressure, and is also easy to install and disassemble. Background Technology

[0002] Composite material pipelines are typically manufactured from fiber-reinforcing materials (such as carbon fiber and glass fiber) and matrix materials (such as epoxy resin and polymers). This combination results in composite material pipelines with lower density and higher strength, making them lighter than traditional metal pipelines, while also possessing higher tensile and flexural strength. Composite material pipelines exhibit excellent corrosion resistance, allowing them to operate in harsh environments such as chemical corrosion, electrochemical corrosion, and seawater corrosion. Compared to metal pipelines, composite material pipelines are not affected by corrosion, oxidation, or corrosive media, thus extending their service life. Due to the composite material composition, composite material pipelines possess high strength and a good elastic modulus, enabling them to effectively disperse and absorb stress, reducing the accumulation of fatigue damage. Therefore, they exhibit excellent fatigue resistance, capable of withstanding long-term cyclic loading without fatigue failure. Furthermore, composite material pipelines exhibit safer failure modes; their failure modes are typically gradual, meaning that obvious warning signs, such as crack propagation and deformation, appear before failure. In contrast, the failure modes of metal pipelines are often sudden, easily leading to serious accidents. The gradual failure modes of composite material pipelines contribute to their higher safety. Furthermore, the raw materials for composite material pipes are abundant, allowing for the selection of suitable fiber and matrix materials based on different needs. Commonly used fiber materials include carbon fiber, glass fiber, and aramid fiber, while matrix materials can include epoxy resin, polyester resin, and polyetherketone. This diversity enables composite material pipes to meet the requirements of various engineering projects. Moreover, the production of composite material pipes consumes low energy and does not require high-temperature melting or extensive metal processing, reducing energy consumption and environmental pollution. These advantages make composite material pipes a promising area for development. Furthermore, fiber-reinforced composite material pipes possess very high pressure resistance and are widely used.

[0003] However, due to the unique material properties of composite material pipes, secondary machining, such as welding and threading, is often difficult. Steel joints, typically made of metal, possess high strength and ductility, and can withstand significant pressure. Currently, steel joints are commonly used for connecting composite materials, securing and sealing the composite pipe to other pipes or equipment through external force. This connection method is simple, reliable, and meets certain mechanical requirements. However, under cyclic charging and discharging conditions, the significant difference in thermal expansion coefficients between the steel joint and the composite material pipe, along with variations in material deformation, can lead to electrochemical corrosion, thermal stress, or mechanical stress. This can cause loosening at the pipe connection, resulting in seal failure and even safety accidents. Therefore, ensuring the safety and airtightness of composite material pipe connections is crucial in practical applications. Summary of the Invention

[0004] (I) Purpose of the Invention

[0005] In view of the above-mentioned defects and shortcomings of the existing technology, and to solve the technical problems that composite material pipes are difficult to process in a secondary manner and often use steel joints to achieve fixation and sealing by external extrusion, which makes the pipe connections prone to loosening, sealing failure and even safety accidents under cyclic filling and discharging conditions due to the different deformation of different materials. This invention provides a composite material pipe interface assembly.

[0006] (II) Technical Solution

[0007] To achieve the objective of this invention and solve its technical problems, the present invention adopts the following technical solution:

[0008] A composite material pipe interface assembly, comprising at least an internal component, an external component, and a sealing ring, characterized in that,

[0009] --The internal component is a tapered tubular part that is open at both ends and extends axially. It sequentially includes, along the axial direction, a large-diameter tail section, an inclined intermediate transition section, and a small-diameter head section.

[0010] The outer wall of the large outer diameter section of the tail is generally inclined, and an annular protrusion is provided on the outer wall of its starting end. A smooth transition structure is provided between the annular protrusion and the outer wall of the large outer diameter section of the tail.

[0011] The outer wall of the intermediate transition section is generally inclined, and its inclination is greater than that of the outer wall of the large outer diameter section at the tail. An external threaded portion extending from its axial head to its axial tail is provided on its inclined outer wall.

[0012] The outer wall of the small outer diameter section of the head is generally straight, and its outer wall surface is processed to form a torque application part, and its inner wall surface is provided with an internal thread for expansion connection.

[0013] --The external component is a cylindrical part with openings at both ends and extending axially. Its outer wall surface is generally flat. Its tail outer wall surface is provided with a high-roughness surface segment that extends axially from the end and has a first axial length. Furthermore, its tail outer wall surface is provided with a plurality of tail slots that extend axially from the end and have an extension length greater than the first axial length.

[0014] The outer wall surface of the head of the external component has an outwardly folded annular flange at its end, and two annular protrusions are spaced apart axially on the outer wall surface of the head. The first annular protrusion is located adjacent to the annular flange, and the second annular protrusion is located near the axial center of the outer wall surface of the external component. The axial space defined between the first and second annular protrusions forms a sealing groove for accommodating the sealing ring. Furthermore, the outer wall surface of the head has a plurality of head slots extending axially from the annular flange towards the tail and having a second axial length. The ends of the head slots are located axially between the two annular protrusions.

[0015] The inner wall surface of the external component is divided into a tail inner wall surface segment and a head inner wall surface segment along the axial direction. The head inner wall surface segment extends axially from its end to near the axial middle position of the external component. Its axial extension length is equivalent to the axial extension length of the intermediate transition segment of the internal component. The head inner wall surface segment is generally inclined conical, and its inner diameter gradually decreases from the tail to the head along the axial direction. It is provided with an internal thread portion that matches the external thread portion of the intermediate transition segment. The axial extension length of the tail inner wall surface segment is equivalent to the axial extension length of the tail large outer diameter segment of the internal component.

[0016] Preferably, a reset ring is provided near the axial center of the outer wall of the large outer diameter section at the tail of the internal component. A plurality of radially extending support ribs are provided circumferentially between the inner wall of the reset ring and the outer wall of the large outer diameter section at the tail. The circumferential width of the slot at the tail of the external component is not less than the circumferential width of the support ribs of the reset ring in the internal component.

[0017] Furthermore, in the assembled state, the external component is inserted into the end interface of the composite material pipe and is axially stopped and positioned by the annular flange face of its head. The sealing ring is provided in the sealing groove on it, and each of the tail slots on it passes through the support ribs of the reset ring in the internal component. The starting end of the inner wall surface section of its tail abuts against the smooth transition structure of the annular protrusion of the internal component. The internal thread of the inner wall surface section of its head meshes with the external thread of the middle transition section of the internal component. Its outer wall surface and the outer wall surfaces of the reset ring and the sealing ring are in contact with the inner wall surface of the composite material pipe.

[0018] Furthermore, when it is necessary to increase the tension and fit between the outer wall surface of the external component and the inner wall surface of the composite material pipe, a rotational torque is applied through the torque application part of the head of the internal component. Through the interlocking of the external thread on the outer wall of the intermediate transition section of the internal component and the internal thread on the inner wall surface of the head of the external component, the entire internal component extends outward axially. The annular protrusion and smooth transition structure of the internal component continuously increase the tension and resistance on the inner wall surface of the tail of the external component, thereby increasing the tension and fit between the outer wall surface of the tail of the external component and its inner wall surface. With the tail slot engaged, it expands radially outward to increase the tension and fit between itself and the inner wall surface of the composite material pipe. Simultaneously, as the intermediate transition section of the internal component moves axially outward, the inner wall surface section of the head of the external component expands radially outward with the engagement of its head slot. This causes the sealing ring on the outer wall surface of the head of the external component to expand radially outward, further increasing the tension and fit between itself and the inner wall surface of the composite material pipe. By compressing the sealing ring, the airtightness between the assembly and the inner wall surface of the composite material pipe is ensured.

[0019] Preferably, when it is necessary to disassemble the assembly from the composite material pipe, a counter-rotating torque is applied to the torque application part of the internal component. The engagement between the external thread of the internal component and the internal thread of the external component causes the entire internal component to move axially inward, thereby reducing the tension between the outer wall surface of the external component, the outer wall surface of the sealing ring, and the inner wall surface of the composite material pipe. Under the action of the reset ring of the internal component, the tail outer wall surface of the external component is gradually reset. Then, the reset assembly is removed from the composite material pipe by means of the annular flange face provided at the head of the external component.

[0020] Preferably, the annular protrusion in the internal component has a chamfered or rounded smooth transition structure between it and the outer wall of the large outer diameter section at the tail; the shape of the starting end of the inner wall surface section at the tail of the external component is adapted to match the smooth transition structure of the annular protrusion on the internal component; when the internal component moves outward under the action of rotational torque, under the action of the annular protrusion and its smooth transition structure in the internal component, the outer wall surface at the tail of the external component expands radially outward with the cooperation of its tail slot to increase the tightness between it and the inner wall surface of the composite material pipe.

[0021] Preferably, in the external component, the outer wall surface of its tail is provided with a sawtooth structure, a frosted structure or a raised ridge structure to form the high roughness surface segment, so as to increase the frictional gripping force between the outer wall surface of the tail of the external component and the inner wall surface of the composite material pipe.

[0022] Preferably, the internal thread on the inner wall surface section of the head of the external component is a tapered or trapezoidal internal thread, and the external thread on the intermediate transition section of the internal component is a tapered or trapezoidal external thread adapted to the internal thread.

[0023] The composite material pipe interface assembly of the present invention, when the outer component is inserted into the end interface of the composite material pipe, utilizes a threaded connection between the inner and outer components. Furthermore, the outer component has slits at both ends. Under the action of the inner component, the outer wall surface of the outer component (with a slit groove at the tail end) and the outer wall surface of the outer component (with a slit groove at the head end) expand radially outward, resulting in a more secure connection between the assembly and the composite material pipe. External constraints further enhance the connection tightness, ensuring safety. Similarly, the inner component's action causes the outer component to expand radially outward, compressing the sealing ring on the outer wall surface of the outer component and ensuring airtightness at the composite material pipe connection. In addition, the inner and outer components employ a disassembly-friendly assembly method, and the internal component's design allows for quick installation and disassembly.

[0024] During installation, the composite material pipe interface assembly of this invention involves first inserting the entire assembly into the composite material pipe, and then applying torque to gradually move the internal components outward along the axial direction. Under the action of the annular protrusion at the tail of the internal component and its smooth transition structure, the tail of the external component expands due to the slit structure, and the high roughness of its outer surface further grips the inner wall of the composite material pipe. Furthermore, combined with external fastening constraints, the connection strength is significantly improved, meeting the requirements for safe application under high pressure. Simultaneously, as the internal component moves, the front end of the external component also expands under the action of the threads of the internal and external components, pressing tightly against the sealing ring, thereby ensuring good airtightness at the connection. In addition, the reset ring designed based on the internal component moves outward with the internal component during disassembly, allowing the expanded external component to retract, thus facilitating disassembly and replacement.

[0025] (III) Technical Effects

[0026] Compared with the prior art, the composite material pipe interface assembly of the present invention has the following beneficial and significant technical effects:

[0027] (1) The composite material pipe interface assembly of the present invention has an internal component that is a tapered tubular component and an external component that is a cylindrical component. The two are connected by a threaded fit and the two ends of the external component are designed with open slots. Under the action of the internal component, the tail and head of the external component expand radially, thereby increasing the degree of fit and friction between the internal component and the inner wall surface of the composite material pipe, ensuring a firm connection, and achieving higher connection strength with external constraints, thus meeting the safety requirements of high-pressure environments.

[0028] (2) The composite material pipe interface assembly of the present invention, as the internal component moves axially, the outer component head expands and squeezes the sealing ring, thereby ensuring the airtightness of the connection and preventing gas leakage.

[0029] (3) The composite material pipe interface assembly of the present invention is based on the reset ring design of the internal component. When disassembling, the internal component moves axially inward, which can realize the shrinkage and reset of the external component, thereby facilitating disassembly and replacement.

[0030] (4) The composite material pipe interface assembly of the present invention has a simple installation process. First, the assembly is inserted into the pipe, and then torque is directly applied to move the internal components to achieve installation. Disassembly is similar; an opposite torque is applied to move the internal components back. Attached Figure Description

[0031] Figure 1 This is a three-dimensional structural schematic diagram of the composite material pipe interface assembly of the present invention;

[0032] Figure 2This is a two-dimensional structural schematic diagram of the composite material pipe interface assembly of the present invention;

[0033] Figure 3 yes Figure 2 A schematic diagram of the AA-direction cross-sectional structure;

[0034] Figure 4 This is a three-dimensional structural diagram of the internal components in this invention;

[0035] Figure 5 yes Figure 4 A schematic diagram of the longitudinal section structure;

[0036] Figure 6 yes Figure 4 Schematic diagram of the cross-sectional structure at the middle reset ring;

[0037] Figure 7 This is a three-dimensional structural diagram of the external components in this invention;

[0038] Figure 8 This is a two-dimensional structural diagram of the external component in this invention;

[0039] Figure 9 yes Figure 8 A schematic diagram of the BB-direction cross-sectional structure.

[0040] Explanation of reference numerals in the attached figures:

[0041] Internal component 10, large outer diameter section at the tail end 11, intermediate transition section 12, small outer diameter section at the head end 13, annular protrusion 14, support rib 15, reset ring 16, external thread section 17, torque application section 18, internal thread section 19, external component 20, high roughness surface section 21, tail slot 22, annular ridge 23, head slot 24, annular flange face 25, sealing ring 30. Detailed Implementation

[0042] To better understand the present invention, the following embodiments further illustrate its content. Throughout the accompanying drawings, the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions. The described embodiments are some, but not all, of the embodiments of the present invention. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, and should not be construed as limiting the present invention. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention. The structure and technical solutions of the present invention will be further described in detail below with reference to the accompanying drawings, providing one embodiment of the present invention.

[0043] like Figures 1-3As shown, the composite material pipe interface assembly of the present invention includes at least an internal component 10, an external component 20, and a sealing ring 30.

[0044] like Figures 4-6 As shown, the internal component 10 is a tapered tubular part that is open at both ends and extends axially. It includes, in sequence along the axial direction, a large outer diameter tail section 11, an inclined intermediate transition section 12, and a small outer diameter head section 13. The outer wall of the large outer diameter tail section 11 is inclined, and an annular protrusion 14 is provided on the outer wall of its starting end. A smooth transition structure is provided between the annular protrusion 14 and the outer wall of the large outer diameter tail section 11. The outer wall of the intermediate transition section 12 is inclined, and its inclination is greater than that of the outer wall of the large outer diameter tail section 11. An external thread 17 extending from its axial head to its axial tail is provided on its inclined outer wall. The outer wall of the small outer diameter head section 13 is straight, and its outer wall surface is processed to form a torque application part 18. An internal thread 19 for expansion connection is provided on its inner wall surface.

[0045] In a preferred embodiment of the present invention, such as Figure 6 As shown, a reset ring 16 is provided near the axial middle position of the outer wall of the large outer diameter section 11 at the tail of the internal component 10. Several radially extending support ribs 15 are provided circumferentially between the inner wall of the reset ring 16 and the large outer diameter section 11 at the tail. The circumferential width of the slot 22 at the tail of the external component 20 is not less than the circumferential width of the support ribs 15 of the reset ring 16 in the internal component 10.

[0046] like Figures 7-9 As shown, the external component 20 is a cylindrical component with open ends and extending axially. Its outer wall surface is generally flat. Its tail outer wall surface is provided with a high roughness surface segment 21 that extends axially from the end and has a first axial length. Its tail outer wall surface is provided with a plurality of tail slots 22 that extend axially from the end and have an extension length greater than the first axial length.

[0047] The outer wall surface of the head of the external component 20 is provided with an outwardly folded annular flange surface 25 at its end, and two annular protrusions 23 are provided axially at intervals on the outer wall surface of the head. The first annular protrusion is located near the annular flange surface 25, and the second annular protrusion is located near the axial middle position of the outer wall surface of the external component 20. The axial space defined between the first annular protrusion and the second annular protrusion 23 forms a sealing groove for providing a sealing ring 30. The outer wall surface of the head is provided with a plurality of head slots 24 extending axially from the annular flange surface 25 to the tail and having a second axial length. The ends of the head slots 24 are located axially between the two annular protrusions 23.

[0048] The inner wall surface of the outer component 20 is divided into a tail inner wall surface section and a head inner wall surface section along the axial direction. The head inner wall surface section extends axially from its end to near the axial middle position of the outer component 20. Its axial extension length is equivalent to the axial extension length of the intermediate transition section 12 of the inner component 10. The head inner wall surface section is generally inclined tapered, and its inner diameter gradually decreases from the tail to the head along the axial direction. It is provided with an internal thread (not shown in the figure) that matches the external thread 17 of the intermediate transition section 12. The axial extension length of the tail inner wall surface section is equivalent to the axial extension length of the tail large outer diameter section 11 of the inner component 10.

[0049] In a preferred embodiment of the present invention, the outer wall surface of the tail of the outer component 20 is formed into a high-roughness surface segment 21 by providing a serrated structure, a frosted structure, or a convex ridge structure, so as to increase the frictional gripping force between the outer wall surface of the tail of the outer component 20 and the inner wall surface of the composite material pipe. In addition, the internal thread portion on the inner wall surface segment of the head of the outer component 20 is a tapered or trapezoidal internal thread, and the external thread portion 17 of the intermediate transition segment 12 of the inner component 10 is a tapered or trapezoidal external thread adapted to the internal thread portion.

[0050] like Figure 3 As shown, when in the assembly state, the external component 20 is inserted into the end interface of the composite material pipe and is axially stopped and positioned by the annular flange face 25 of its head. A sealing ring 30 is provided in the sealing groove on it, and each of the tail slots 22 on it passes through the support ribs 15 of the reset ring 16 in the internal component 10. The starting end of the inner wall surface section of its tail abuts against the smooth transition structure of the annular protrusion 14 of the internal component 10. The internal thread of the inner wall surface section of its head meshes with the external thread 17 of the intermediate transition section 12 of the internal component 10. Its outer wall surface and the outer wall surfaces of the reset ring 16 and the sealing ring 30 are in contact with the inner wall surface of the composite material pipe.

[0051] When it is necessary to increase the tension and fit between the outer wall surface of the outer component 20 and the inner wall surface of the composite material pipe, a rotational torque is applied through the torque application part 18 at the head of the inner component 10. The engagement between the external thread 17 on the outer wall of the intermediate transition section 12 of the inner component 10 and the internal thread on the inner wall surface of the head of the outer component 20 causes the inner component 10 to extend axially outwards continuously. The annular protrusion 14 and its smooth transition structure of the inner component 10 continuously increase the tension and contact with the inner wall surface of the tail of the outer component 20, thereby increasing the tension and fit between the outer wall surface of the tail of the outer component 20 and the inner wall surface of the outer component 20. With the cooperation of the tail slot 22, it expands radially outward to increase the tension and tightness between it and the inner wall surface of the composite material pipe. At the same time, as the intermediate transition section 12 of the inner component 10 moves axially outward, the inner wall surface section of the head of the outer component 20 expands radially outward with the cooperation of its head slot 24. This causes the sealing ring 30 located on the outer wall surface of the head of the outer component 20 to expand radially outward, thereby increasing the tension between it and the inner wall surface of the composite material pipe. By compressing the sealing ring 30, the airtightness between the assembly and the inner wall surface of the composite material pipe is ensured.

[0052] When it is necessary to disassemble the assembly from the composite material pipe, a counter-rotating torque is applied to the torque application part 18 of the inner component 10. The engagement between the external thread part 17 of the inner component 10 and the internal thread part of the outer component 20 causes the inner component 10 to move axially inward as a whole. This reduces the tension between the outer wall surface of the outer component 20, the outer wall surface of the sealing ring 30, and the inner wall surface of the composite material pipe. Under the action of the reset ring 16 of the inner component 10, the tail outer wall surface of the outer component 20 is gradually reset. Then, the reset assembly is removed from the composite material pipe by means of the annular flange face 25 provided at the head of the outer component 20.

[0053] In a preferred embodiment of the present invention, the annular protrusion 14 in the inner component 10 has a chamfered or rounded smooth transition structure between it and the outer wall of the large outer diameter section 11 at the tail; the shape of the starting end of the inner wall surface section at the tail of the outer component 20 is adapted to match the smooth transition structure of the annular protrusion 14 on the inner component 10; when the inner component 10 moves outward under the action of rotational torque, under the action of the annular protrusion 14 and its smooth transition structure of the inner component 10, the outer wall surface at the tail of the outer component 20 expands radially outward with the cooperation of its tail slot 22 to increase the tightness between it and the inner wall surface of the composite material pipe.

[0054] The composite material pipe interface assembly of the present invention, when the outer component 20 is inserted into the end interface of the composite material pipe, due to the threaded engagement between the inner and outer components and the slit treatment at both ends of the outer component, causes the outer wall surface with the tail slit groove 22 and the outer wall surface with the head slit groove 24 of the outer component to expand radially outward under the action of the inner component, making the connection between the assembly and the composite material pipe more secure. On this basis, the external constraint can further enhance the connection tightness, thereby ensuring safety; similarly, the action of the inner component causes the outer component to expand radially outward, thereby squeezing the sealing ring 30 set on the outer wall surface of the outer component 20, ensuring the airtightness of the composite material pipe connection; in addition, the inner and outer components adopt an easy-to-disassemble engagement method, and a reset structure is designed based on the inner component, thereby realizing quick installation and disassembly.

[0055] During installation, the composite material pipe joint assembly of the present invention is first inserted entirely into the composite material pipe, and then torque is applied to gradually move the internal components outward along the axial direction. Under the action of the annular protrusion 14 at the tail of the internal component and its smooth transition structure, the tail of the external component expands due to the slit structure, and the high roughness of its outer wall surface further grips the inner wall of the composite material pipe. Furthermore, combined with external fastening constraints, the connection strength is significantly improved, meeting the requirements for safe application under high pressure. Simultaneously, as the internal component moves, the front head of the external component also expands under the action of the threads of the internal and external components, pressing tightly against the sealing ring, thereby ensuring good airtightness at the connection. In addition, the reset ring designed based on the internal component moves outward with the internal component during disassembly, allowing the expanded external component to retract, thus facilitating disassembly and replacement.

[0056] The objectives of this invention have been fully and effectively achieved through the above embodiments. Those skilled in the art will understand that this invention includes, but is not limited to, the contents described in the accompanying drawings and the specific embodiments described above. Although the invention has been described with reference to what is currently considered the most practical and preferred embodiments, it should be understood that the invention is not limited to the disclosed embodiments, and any modifications that do not depart from the functional and structural principles of the invention will be included within the scope of the claims.

Claims

1. A composite material pipe interface assembly, comprising at least an internal component, an external component, and a sealing ring, characterized in that, The internal component is a tapered tubular part that is open at both ends and extends axially. Along the axial direction, it sequentially includes a large-diameter tail section, an inclined intermediate transition section, and a small-diameter head section. The outer wall of the large outer diameter section of the tail is generally inclined, and an annular protrusion is provided on the outer wall of its starting end. A smooth transition structure is provided between the annular protrusion and the outer wall of the large outer diameter section of the tail. The outer wall of the intermediate transition section is generally inclined, and its inclination is greater than that of the outer wall of the large outer diameter section at the tail. An external threaded portion extending from its axial head to its axial tail is provided on its inclined outer wall. The outer wall of the small outer diameter section of the head is generally straight, and its outer wall surface is processed to form a torque application part, and its inner wall surface is provided with an internal thread for expansion connection. The external component is a cylindrical part that is open at both ends and extends axially. Its outer wall surface is generally flat. Its tail outer wall surface is provided with a high-roughness surface segment that extends axially from the end and has a first axial length. Furthermore, its tail outer wall surface is provided with a plurality of tail slots that extend axially from the end and have an extension length greater than the first axial length. The outer wall surface of the head of the external component has an outwardly folded annular flange at its end, and two annular protrusions are spaced apart axially on the outer wall surface of the head. The first annular protrusion is located adjacent to the annular flange, and the second annular protrusion is located near the axial center of the outer wall surface of the external component. The axial space defined between the first and second annular protrusions forms a sealing groove for accommodating a sealing ring. Furthermore, the outer wall surface of the head has a plurality of head slots extending axially from the annular flange towards the tail and having a second axial length. The ends of the head slots are located axially between the two annular protrusions. The inner wall surface of the external component is divided into a tail inner wall surface segment and a head inner wall surface segment along the axial direction. The head inner wall surface segment extends axially from its end to near the axial middle position of the external component. Its axial extension length is equivalent to the axial extension length of the intermediate transition segment of the internal component. The head inner wall surface segment is generally inclined conical, and its inner diameter gradually decreases from the tail to the head along the axial direction. It is provided with an internal thread portion that matches the external thread portion of the intermediate transition segment. The axial extension length of the tail inner wall surface segment is equivalent to the axial extension length of the large outer diameter tail segment of the internal component. A reset ring is provided near the axial center of the outer wall of the large outer diameter section at the tail of the internal component. A number of radially extending support ribs are provided circumferentially between the inner wall of the reset ring and the outer wall of the large outer diameter section at the tail. The circumferential width of the slot at the tail of the external component is not less than the circumferential width of the support ribs of the reset ring in the internal component. When in the assembly state, the external component is inserted into the end interface of the composite material pipe and is axially stopped and positioned by the annular flange face of its head. A sealing ring is provided in the sealing groove on it. Each of the tail slots on it passes through the support ribs of the reset ring in the internal component. The starting end of the inner wall surface section of its tail abuts against the smooth transition structure of the annular protrusion of the internal component. The internal thread of the inner wall surface section of its head meshes with the external thread of the middle transition section of the internal component. Its outer wall surface and the outer wall surfaces of the reset ring and the sealing ring are in contact with the inner wall surface of the composite material pipe.

2. The composite material pipe interface assembly according to claim 1, characterized in that, When it is necessary to increase the tension and fit between the outer wall surface of the external component and the inner wall surface of the composite material pipe, a rotational torque is applied through the torque application part of the head of the internal component. The engagement between the external thread on the outer wall of the intermediate transition section of the internal component and the internal thread on the inner wall surface of the head of the external component causes the entire internal component to extend outward axially. The annular protrusion and smooth transition structure of the internal component continuously increase the tension and pressure on the inner wall surface of the tail of the external component, thereby causing the outer wall surface of the tail of the external component to... With the cooperation of the slotted part, it expands radially outward to increase the tension and tightness between it and the inner wall surface of the composite material pipe. At the same time, as the intermediate transition section of the internal component moves axially outward, the inner wall surface section of the head of the external component expands radially outward with the cooperation of its head slot. This causes the sealing ring on the outer wall surface of the head of the external component to expand radially outward, thereby increasing the tension and tightness between it and the inner wall surface of the composite material pipe. By compressing the sealing ring, the airtightness between the assembly and the inner wall surface of the composite material pipe is ensured.

3. The composite material pipe interface assembly according to claim 1, characterized in that, When it is necessary to disassemble the assembly from the composite material pipe, a counter-rotating torque is applied to the torque application part of the internal component. The engagement between the external thread of the internal component and the internal thread of the external component causes the entire internal component to move axially inward. This reduces the tension between the outer wall surface of the external component, the outer wall surface of the sealing ring, and the inner wall surface of the composite material pipe. Under the action of the reset ring of the internal component, the tail outer wall surface of the external component is gradually reset. Then, the reset assembly is removed from the composite material pipe by means of the annular flange face provided at the head of the external component.

4. The composite material pipe interface assembly according to claim 1, characterized in that, The annular protrusion in the internal component has a chamfered or rounded smooth transition structure between it and the outer wall of the large outer diameter section at the tail. The shape of the starting end of the inner wall surface section at the tail of the external component is adapted to match the smooth transition structure of the annular protrusion on the internal component. When the internal component moves outward under the action of rotational torque, under the action of the annular protrusion and its smooth transition structure in the internal component, the outer wall surface at the tail of the external component expands radially outward with the cooperation of its tail slot to increase the tightness between it and the inner wall surface of the composite material pipe.

5. The composite material pipe interface assembly according to claim 1, characterized in that, In the external component, the outer wall surface of its tail is formed into a high-roughness surface segment by setting a sawtooth structure, a frosted structure or a convex ridge structure, so as to increase the frictional gripping force between the outer wall surface of the tail of the external component and the inner wall surface of the composite material pipe.

6. The composite material pipe interface assembly according to claim 1, characterized in that, The internal thread on the inner wall surface of the head of the external component is a tapered or trapezoidal internal thread, and the external thread on the intermediate transition section of the internal component is a tapered or trapezoidal external thread that matches the internal thread.

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