RTP pipe joint sealing structure for high-pressure gas gathering and transportation

Abstract

The utility model relates to an RTP pipe joint sealing structure for high-pressure gas gathering and transportation. The RTP pipe joint sealing structure comprises a joint core pipe, a sleeve and a pipe body. One end of the joint core pipe is provided with a sealed end, and the other end of the joint core pipe is connected by being embedded in the pipe body; external threads are arranged on the outer ring of the joint core tube; one end of the sleeve is provided with internal threads; the joint core pipe is in threaded connection with the internal thread through the external thread; the other end of the sleeve is nested outside the pipe body; an annular sealing groove is further formed in the outer wall of the connector core pipe. An O-shaped rubber sealing ring and a plastic check ring are mounted in the annular sealing groove; the cross section of the annular sealing groove is square or trapezoid, and the cross section of the plastic check ring is also arranged to be of a square or trapezoid or polygonal structure corresponding to the cross section of the annular sealing groove. According to the utility model, the assembly size is more accurately controlled, so that the assembly connection gap between the pipe and the joint is tighter, and the sealing effectiveness is fully ensured.

Description

Technical Field

[0001] The utility model relates to the technical field of gas gathering and transportation, in particular to an RTP pipe joint sealing structure for high-pressure gas gathering and transportation. Background Art

[0002] The fiber-reinforced plastic composite pipe (RTP pipe) adopts a multi-layer structure, which is composed of three layers: a plastic inner lining layer, a fiber-reinforced layer, and a plastic outer protective layer; the RTP pipe has the advantages of high pressure resistance, corrosion resistance, good flexibility, long continuous length, and few joints, and is now widely used in the fields of oil and gas, and the transportation of toxic, harmful, flammable, and explosive liquids and gases in the chemical industry. Due to the relatively high transportation pressure, metal joints are usually used for the connection of RTP pipes. In the pipeline for transporting high-pressure gas, because the molecular weights of gases such as CH4 and H2 are relatively small, with the prolongation of the operation time, a small amount of gas molecules will penetrate through the inner lining layer and the gap between the joint and the inner lining layer into the fiber-reinforced layer, and even escape into the soil or air. As the gas continuously accumulates, it will cause the outer protective layer to bulge or even rupture, resulting in leakage accidents. It may also crush the inner lining pipe when the transportation pressure drops suddenly, causing the RTP pipe to fail.

[0003] Existing conventional pipe joints usually have several undulating teeth on the outer wall of the core pipe and the inner wall of the sleeve. An O-ring seal assembly groove is provided on the outer wall of the core pipe. After assembling the joint and the pipe, the pipe is fastened between the core pipe and the sleeve of the joint by radially crimping the sleeve to form a connection. Under the high pressure of the transported medium, the plastic pipe body between the core pipe and the sleeve of the joint will deform, and the tight fit gap between the pipe body and the joint will increase with the increase of the pressure, and the sealing effect of the O-ring will gradually weaken, resulting in air leakage. In addition, as the fit gap becomes larger, the O-ring is more likely to be squeezed into the fit gap, thereby causing damage to the O-ring and resulting in air leakage.

[0004] Therefore, the prior art not only needs to design a pipe body with a gas barrier function to prevent gas penetration, but also needs to prevent the problem of gap leakage at the connection between the pipe and the joint. Summary of the Utility Model

[0005] The purpose of the utility model is to provide an RTP pipe joint sealing structure for high-pressure gas gathering and transportation, so as to solve the problem of gas leakage at the gap existing after the assembly and connection of the existing pipe and the joint.

[0006] To achieve the above purpose, the utility model provides the following technical solutions:

[0007] The utility model relates to a sealing structure of an RTP pipe joint for high-pressure gas gathering and transportation, which comprises a joint core pipe, a sleeve and a pipe body; one end of the joint core pipe is provided with a sealing end, and the other end of the joint core pipe is connected by being embedded in the pipe body; an external thread is arranged on the outer circle of the joint core pipe; an internal thread is arranged at one end of the sleeve; the joint core pipe is threadedly connected with the internal thread through the external thread, and the other end of the sleeve is nested outside the pipe body; an annular sealing groove is further formed on the outer wall of the joint core pipe; an O-shaped rubber sealing ring and a plastic retaining ring are installed in the annular sealing groove; the cross-section of the annular sealing groove is square or trapezoidal, and the cross-section of the plastic retaining ring is also set to a square, trapezoidal or polygonal structure corresponding to the cross-section of the annular sealing groove; the included angle between one side groove surface of the annular sealing groove and the horizontal plane is θ, and 30°≤θ≤90°; annular teeth are further formed on the connecting surfaces among the joint core pipe, the sleeve and the pipe body; the sleeve is further provided with an exhaust hole, and the exhaust hole penetrates through the dense space formed when the joint core pipe, the sleeve and the pipe body are connected.

[0008] In the above-mentioned sealing structure of the RTP pipe joint for high-pressure gas gathering and transportation, the annular sealing groove comprises a first annular sealing groove and a second annular sealing groove; annular teeth are spaced on the outer pipe wall between the first annular sealing groove and the second annular sealing groove.

[0009] In the above-mentioned sealing structure of the RTP pipe joint for high-pressure gas gathering and transportation, the pipe body comprises a lining layer for conveying a medium, a fiber-reinforced layer for providing the pipe body with an internal pressure bearing capacity, and an outer protective layer for protecting the fiber-reinforced layer; annular teeth are formed on the connecting surfaces of the sleeve connected to the outer protective layer and the core pipe connected to the lining layer.

[0010] In the above-mentioned sealing structure of the RTP pipe joint for high-pressure gas gathering and transportation, the end face of the sealing end is a plane, a multi-step face with a sealing groove structure or a flange.

[0011] In the above-mentioned sealing structure of the RTP pipe joint for high-pressure gas gathering and transportation, the O-shaped rubber sealing ring is one of nitrile rubber, fluororubber, hydrogenated nitrile rubber, silicone rubber, fluorosilicone rubber, fluorocarbon rubber, ethylene propylene diene monomer rubber; the Shore hardness of the O-shaped sealing ring is D60~D95; the plastic retaining ring is one or more of nylon, polytetrafluoroethylene, polyether ether ketone, polyoxymethylene, and the annular surface of the annular sealing groove is parallel to the annular surface of the plastic retaining ring.

[0012] The beneficial effects of the utility model are as follows:

[0013] When the pipe body is installed in the core pipe and the sleeve of the joint, a plastic retaining ring corresponding to the inclination angle of the sealing groove surface is further arranged, and an O-shaped sealing ring is matched, and the assembly dimensions are more precisely controlled, so that the assembly connection gap between the pipe and the joint is closer, and the effectiveness of sealing is fully ensured. Brief Description of the Drawings

[0014] Figure 1 Schematic diagram of the connection structure between the pipe joint and the pipe body of the utility model;

[0015] Figure 2 is Figure 1 the enlarged structural schematic diagram at position A in

[0016] Figure 3 is Figure 1 the enlarged structural schematic diagram at position B in

[0017] Figure 4 is Figure 1 another enlarged structural schematic diagram at position B in

[0018] Figure 5 the structural schematic diagram of the joint core tube of the present utility model;

[0019] Figure 6 is Figure 5 the enlarged structural schematic diagram at position C in

[0020] Figure 7 the structural schematic diagram of the joint sleeve of the present utility model.

[0021] In the figure:

[0022] 1 - joint core tube; 11 - sealing end; 12 - second annular sealing groove; 13 - first annular sealing groove; 14 - external thread; 2 - sleeve; 21 - exhaust hole; 22 - internal thread; 3 - pipe body; 31 - outer protective layer; 32 - fiber reinforced layer; 33 - inner lining layer; 4 - plastic retaining ring; 5 - O-ring rubber seal. Specific embodiments

[0023] In order to make the objectives, technical solutions and advantages of the present utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present utility model and are not used to limit the present utility model.

[0024] Refer to Figures 1 to 7 , the present utility model is composed of an RTP pipe body 3, a joint core tube 1 for installing an O-ring rubber seal 5 and a plastic retaining ring 4, and a sleeve 2. The inner and outer diameters of the RTP pipe body 3 are first machined by turning. The joint is composed of the joint core tube 1 and the sleeve 2 using internal expansion and / or piercing tube shrinking, which can more precisely control the assembly dimensions and make the assembly connection gap between the pipe and the joint tighter, thus fully ensuring the effectiveness of the seal.

[0025] The RTP pipe body 3 includes a lining layer 33 for transporting the medium, a fiber-reinforced layer 32 for providing the pipe body with internal pressure bearing capacity, and an outer protective layer 31 for protecting the fiber-reinforced layer; the joint consists of a joint core pipe 1 and a sleeve 2. There is an external thread 14 for assembling with the sleeve 2 after the sealing end 11. A number of tooth shapes, a first annular sealing groove 13 and a second annular sealing groove 12 are provided on the outer wall of the socket end. An O-ring rubber seal 5 and a plastic retaining ring 4 are installed in the sealing groove. In the working state, the retaining ring 4 can prevent the O-ring from being extruded out of the sealing groove by high-pressure gas, resulting in sealing failure. Moreover, the higher the internal pressure, the greater the tendency of the retaining ring 4 to slide along the inclined annular vertical surface of the sealing groove towards the sealing end of the joint, and the closer the retaining ring 4 is pressed against the lining layer 33 of the RTP pipe, which fully ensures the effectiveness of the seal. The sleeve 2 is assembled with the external thread 14 of the joint core pipe 1 through the internal thread 22 at the front end. At least one exhaust hole 21 is provided in the transition area between the threaded assembly section and the socket section. A number of tooth shapes are provided on the inner wall of the socket section of the sleeve 2. The exhaust hole 21 is used to reduce the pressure in the closed space formed when the joint core pipe 1, the sleeve 2 and the pipe body 3 are connected.

[0026] The sealing end 11 of the joint core pipe 1 can be in the form of a plane, a multi-step surface with a sealing groove structure, a flange, etc.

[0027] There are several tooth shape distances between the first annular sealing groove 13 and the second annular sealing groove 12. The cross-section of the first annular sealing groove 13 and the second annular sealing groove 12 can be one of the shapes such as square, trapezoid, etc., that is, the angle θ between the annular vertical surface where the sealing groove cooperates with the side surface of the retaining ring and the axis satisfies 30° ≤ θ ≤ 90°, as shown in the enlarged views of B and C in Figure 3 、 Figure 4 、 Figure 6 For gas gathering and transportation pipelines with a relatively low pressure grade, the annular sealing groove structure can be square. For gas gathering and transportation pipelines with a relatively high pressure grade, the annular sealing groove structure is preferably trapezoidal, that is, the angle θ between the annular vertical surface where the sealing groove cooperates with the side surface of the retaining ring and the axis satisfies 30° ≤ θ < 90°.

[0028] The O-ring rubber seal 5 is selected from one of nitrile rubber, fluororubber, hydrogenated nitrile rubber, silicone rubber, fluorosilicone rubber, fluorocarbon rubber, ethylene propylene diene monomer rubber, and fluororubber is preferably used; the Shore hardness of the O-ring seal 5 is between D60 and D95.

[0029] The material of the plastic retaining ring 4 is selected from one of nylon, polytetrafluoroethylene, polyether ether ketone, polyoxymethylene or a mixture of one or more of these materials. The cross-sectional shape of the plastic retaining ring 4 can be one of the shapes such as square, trapezoid or polygon that matches the annular sealing groove, and its side surface is parallel to the annular vertical surface of the sealing groove.

[0030] Implementation methods for assembling the pipe material and the joint:

[0031] 1. Install the O-ring seal 5 and the plastic retaining ring 4 into the first annular seal groove 13 and the second annular seal groove 12 respectively;

[0032] 2. Connect and tighten the sleeve 2 and the joint core pipe 1 through the external thread 14 and the internal thread 22;

[0033] 3. According to the outer diameter dimension of the joint core pipe 1 and the inner diameter dimension of the sleeve 2, machine the inner diameter of the liner 33 and the outer diameter of the outer protective layer 31 of the RTP pipe body 3 to be assembled by turning and other machining methods to the required dimensions;

[0034] 4. Pass the pull rod and the internal expansion die head of the joint assembly tooling through the joint core pipe 1 to perform internal expansion treatment on the joint core pipe 1;

[0035] 5. Measure and mark the length equal to the straight section of the sleeve 2 at the head of the RTP pipe body 3, and sleeved the machined RTP pipe body 3 and the joint core pipe 1 until the mark overlaps with the tail of the sleeve 2;

[0036] 6. Connect the pull rod with the joint assembly equipment, and start the equipment to pull out the internal expansion die head from the joint core pipe 1 to complete the tube expansion of the joint core pipe 1;

[0037] 7. Install the pipe shrinking die of the joint assembly equipment, and start the equipment to pass the sleeve 2 of the joint through the pipe shrinking die to complete the compression of the sleeve 2.

[0038] In the description of this technical solution, it should be understood that the words indicating the orientation or positional relationship are based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present invention.

[0039] The terms "install", "assemble", and "connect" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present invention can be understood through specific situations.

[0040] The above is only the preferred specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art within the technical scope disclosed by the present invention, according to the technical solution and the inventive concept of the present invention, makes equivalent substitutions or changes, and should be covered by the protection scope of the present invention.

Claims

1. A RTP pipe joint sealing structure for high-pressure gas gathering and transportation, characterized in that: The invention comprises a joint core tube (1), a sleeve (2) and a tube body (3); one end of the joint core tube (1) is provided with a sealing end (11), and the other end of the joint core tube (1) is connected by being embedded in the tube body (3); the outer ring of the joint core tube (1) is provided with an external thread (14); one end of the sleeve (2) is provided with an internal thread (22); the joint core tube (1) is threadedly connected with the internal thread (22) through the external thread (14), and the other end of the sleeve (2) is embedded in the outside of the tube body (3); the outer wall of the joint core tube (1) is also provided with an annular sealing groove; an O-type rubber seal is installed in the annular sealing groove The annular sealing groove has a square or trapezoidal cross section, and the plastic retaining ring (4) has a square or trapezoidal cross section or a polygonal cross section corresponding to the annular sealing groove cross section; the angle between the groove surface on one side of the annular sealing groove and the horizontal plane is θ, and 30°≤θ≤90°; annular teeth are also provided on the connecting surfaces between the joint core tube (1), the sleeve (2) and the tube body (3); the sleeve (2) is also provided with an exhaust hole (21), and the exhaust hole (21) passes through the closed space formed when the joint core tube (1), the sleeve (2) and the tube body (3) are connected.

2. The RTP pipe joint sealing structure for high-pressure gas gathering and transportation according to claim 1 is characterized in that: The annular sealing groove comprises a first annular sealing groove (13) and a second annular sealing groove (12); annular teeth are spaced apart on the outer tube wall between the first annular sealing groove (13) and the second annular sealing groove (12).

3. The RTP pipe joint sealing structure for high-pressure gas gathering and transportation according to claim 1 is characterized in that: The pipe body (3) comprises an inner lining layer (33) for conveying a medium, a fiber reinforcement layer (32) for providing the pipe body with an internal pressure bearing capacity, and an outer protective layer (31) for protecting the fiber reinforcement layer; annular teeth are provided on the connecting surfaces of the outer protective layer (31) and the sleeve (2), and the inner lining layer (33) and the joint core pipe (1).

4. The RTP pipe joint sealing structure for high-pressure gas gathering and transportation according to claim 1 is characterized in that: The end face of the sealing end (11) is a flat surface, a multi-step surface with a sealing groove structure, or a flange.

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