CN216976190U - Flexible joint of large diameter high pressure fiber reinforced flexible composite pipe - Google Patents

Abstract

The utility model relates to a flexible joint of a large-diameter high-pressure fiber-reinforced flexible composite pipe, which belongs to the field of fiber-reinforced thermoplastic pipes. Its technical scheme: the reinforcing layer is formed by spiral winding of fiber tapes, the reinforcing layer is at least 2-layer structure, and the spiral winding direction of the adjacent layers of fiber tapes is opposite; the filling layer is arranged between the adjacent layers of the reinforcing layer, and the filling layer is made of extrudable layers. Composed of compressively deformed elastic material; the fiber band exceeds the end of the inner liner by a certain distance. The utility model provides thicker fiber tapes, reduces the winding times of the fiber tapes, facilitates the processing of fiber-reinforced flexible composite pipes, and facilitates the flexible connection of pipes; the problem of stress concentration of reinforcement layers caused by metal joints can be avoided, and the insufficient strength of welded joints can be solved at the same time. The problem. The technical scheme of the utility model can meet the needs of oil and gas pipeline transportation and other application occasions.

Description

Flexible joint of large diameter high pressure fiber reinforced flexible composite pipe

technical field

The utility model relates to a flexible joint of a large-diameter high-pressure fiber-reinforced flexible composite pipe, belonging to the field of pipeline transportation, in particular to the field of fiber-reinforced thermoplastic pipes.

Background technique

Reinforced Thermoplastic Pipes (RTP pipes for short) are high-pressure plastic composite pipes with good flexibility, corrosion resistance, high pressure resistance, impact resistance, wear resistance, light weight, easy connection, and coilability. , long-distance jointless rapid laying, etc., can well overcome the corrosion problem of steel pipes and the pressure resistance problem of plastic pipes, and can be used in oil and natural gas exploration, high-pressure long-distance transportation of natural gas and various transportation media requiring higher pressure. pipeline field. RTP products are usually composed of three layers. The inner and outer layers are made of PE80 and PE100 materials. The outer layer can be white (UV-proof on the ground) or black (buried laying) as required; the middle layer is a composite of reinforcing materials. Belt, the reinforcing material can be high-strength fibers such as aramid fiber, polyester fiber or glass fiber.

The existing technical solutions use various types of fibers as reinforcement layers to improve the pressure bearing capacity of the pipeline, and there are already many mature products. According to SYT 6662.2-2012 "Non-metallic composite pipes for the oil and gas industry - Part 2: Flexible composite high-pressure conveying pipes", the current general flexible composite pipes have a maximum inner diameter of 150mm and a nominal pressure of 6.4MPa/2.5MPa; the nominal diameter of flexible composite pipes below 90mm The pressure is up to 12MPa. Some enterprises can process flexible composite pipes with a diameter of more than 1m, but the pressure-bearing capacity is low, and they are mainly used for low-pressure water delivery.

The existing fiber-reinforced flexible composite pipe connection mainly adopts two forms of metal joint and welding joint. The metal joint is inserted into the pipeline with a metal inner tube, and the end of the pipeline is clamped by winding or tapered sleeve on the outside, and the metal joints are connected by threaded connection or flange connection. The welding joint mainly refers to the capacitor joint. The thermoplastic material is set in the cylindrical joint, and the metal wire is embedded in advance.

The existing connection technology mainly has the following problems: (1) The metal joint has local constraints at the end of the pipeline, the deformation of the pipeline after pressure is uncoordinated, and the pressure bearing capacity is low; If the pressure is too large, it is easy to damage the fibers, and if the pressure is too small, the restraint is insufficient, and it is difficult to achieve the ideal connection strength in practical applications. (2) The connection part is set with a sleeve and connected by welding. The protective layers of the pipes at both ends are directly fused with the joints, and the reinforcement layers cannot be effectively connected, and the pipes are easily pulled out under the action of the axial force.

Since the 21st century, the pipeline transportation industry has vigorously promoted the strategic development plan of "replacing steel with plastic", and flexible composite pipelines have been listed as the key development direction due to their excellent performance, and are developing towards high pressure and large diameter. In the field of oil and gas transportation, pipeline pressure is high, and there is a clear demand for large diameters. At present, long-distance pipelines are mainly made of steel, with a maximum diameter of 1216mm and a nominal pressure of more than 10MPa; the existing flexible composite pipe connection technology is difficult to adapt to high-pressure, large-diameter pipelines.

Aiming at the problem of fiber-reinforced flexible composite pipeline connection, patent CN2021107151712 proposes a new flexible connection method: the inner lining layer is welded, then the reinforcing layer is overlapped and wound according to the rotation direction of each layer, and finally a protective layer is provided outside the joint. The solution can avoid the problem of stress concentration of the reinforcement layer caused by the metal joint, and at the same time solve the problem of insufficient strength of the welded joint. However, in the face of dozens of layers of reinforced fiber belts, the construction of this scheme is difficult, the construction time is long, and it is difficult to popularize and apply.

The existing fiber-reinforced flexible composite pipe reinforcement layer processing mainly adopts tape winding with a thickness of less than 1mm. High-pressure pipelines, the thickness of the reinforcement layer is large, and multi-layer winding is required. As a result, the pipeline production line needs to be equipped with multiple sets of tape winding mechanisms, and the coordination between equipment is difficult to control. At present, the fibers in the fiber tape are arranged in a straight line and add adhesive, and the fiber tape is wound and bent, causing the inner layer fibers to be compressed and the outer layer fibers to be pulled. Excessive thickness of the fiber tape will cause uneven stress on the fiber and affect its strength; therefore, it is necessary to reduce the thickness of the fiber tape as much as possible in the current construction. Adopting a reasonable winding structure and increasing the thickness of the winding can effectively reduce the winding times of the fiber tape, and facilitate the processing of fiber-reinforced flexible composite pipes by one-time molding.

Based on the above background, the development of thicker fiber tapes to reduce the number of winding times of fiber tapes is conducive to the processing of fiber-reinforced flexible composite pipes and facilitates the flexible connection of pipes. The technical requirements of high-pressure flexible composite pipelines can expand the application scope of composite pipelines in the field of oil and gas output.

SUMMARY OF THE INVENTION

The purpose of the utility model: in order to overcome the problem that the existing fiber-reinforced flexible composite pipe joint has low pressure bearing capacity and is not suitable for large-diameter and high-pressure pipes; solve the problem of discontinuous force transmission of the reinforcing layer of the flexible composite pipe joint; provide a thickness The larger fiber tape reduces the winding times of the fiber tape, which is beneficial to the processing of fiber-reinforced flexible composite pipes and facilitates the flexible connection of pipes.

In order to achieve the above-mentioned purpose, the technical scheme adopted by the present utility model is as follows.

The flexible joint of the large-diameter high-pressure fiber-reinforced flexible composite pipe includes an inner lining layer, a reinforcing layer and a filling layer, and is characterized in that a reinforcing layer is arranged outside the inner lining layer, and the inner lining layer of the flexible joint is connected with the inner lining layer of the pipeline. connection, the reinforcing layer of the flexible joint is connected with the reinforcing layer of the pipeline; the reinforcing layer is formed by spiral winding of fiber tapes, the reinforcing layer is at least 2-layer structure, and the spiral winding directions of the adjacent layers of fiber tapes are opposite; the filling layer is arranged on the reinforcing layer Between the adjacent layers, the filling layer is composed of extrudable elastic materials; the fiber belt exceeds the end of the inner lining layer by a certain distance, and the distance is more than 0.5 times the inner diameter of the inner lining layer; the fiber belt is composed of at least 2 The windings are formed by adding adhesives side by side, and the adhesive of the windings is close to the inner side of the pipe or is located in the adjacent parts between the windings.

The winding is made up of at least 3 fiber bundles spirally wound with each other, and the twist of each fiber bundle of the winding is the same and greater than zero.

The fiber bundles wound in adjacent layers are helically wound in opposite directions.

An inner core is arranged at a middle position inside the winding, the cross section of the inner core is circular or annular, and the inner core is an elastic material.

The filling layer is a belt-like structure and is spirally wound into a cylindrical shape.

The filling layer is a rubber material.

The inner layer fiber belt of the flexible joint is long, and the outer layer fiber belt is short, and the length gradually decreases from the inner layer to the outer layer fiber belt.

The single reinforcement layer of the flexible joint is formed by helically winding a fiber ribbon.

It also includes a wedge-shaped ring, characterized in that: the wedge-shaped ring is arranged at the end of the fiber belt, the wedge-shaped ring is a split ring, the wedge-shaped ring is composed of a compressible and deformable elastic material, and the annular cross-section of the wedge-shaped ring is wedge-shaped.

The beneficial effects of the utility model are: (1) the utility model overlaps the reinforcing layers in multiple layers, and the interlayers pass through the wedge-shaped ring transition, which effectively enhances the strength of the reinforcing layer at the joint part; (2) the flexibility constraint of the reinforcing layer at the joint part can avoid The metal joint causes the problem of stress concentration of the reinforcement layer, and at the same time solves the problem of insufficient strength of the welded joint; (3) Provide a thicker fiber tape, reduce the number of winding times of the fiber tape, which is conducive to the processing of fiber-reinforced flexible composite pipes and facilitates flexible connection of pipes ; (4) The technical scheme of the present utility model can effectively and high-strength connect large-diameter high-pressure fiber-reinforced flexible composite pipes to meet the needs of oil and gas pipeline transportation and other applications.

Description of drawings

Fig. 1 is the structural diagram of the utility model.

FIG. 2 is a schematic diagram of the winding of the fiber tape according to the present invention.

FIG. 3 is a partial enlarged view of FIG. 1 .

FIG. 4 is a schematic cross-sectional view of the fiber tape of the present invention.

FIG. 5 is a schematic diagram of the winding structure of the utility model.

6 is a schematic cross-sectional view of the winding according to the present invention.

In the figure: 1. Inner liner; 2. Reinforcing layer; 3. Protective layer; 4. Wedge ring; 21. Tape; 22. Filling layer; 211. Winding; 2112. Inner core.

Detailed ways

The present invention is not limited by the following examples, and specific implementations can be determined according to the technical solutions and actual conditions of the present invention. The positional relationships of up, down, left, right, front, rear, inner and outer are determined according to the layout direction of FIG. 1 in the specification.

The flexible joint of the large-diameter high-pressure fiber-reinforced flexible composite pipe includes an inner lining layer 1 , a reinforcing layer 2 and a filling layer 22 .

A reinforcement layer 2 is arranged outside the inner lining layer 1, the inner lining layer 1 of the flexible joint is connected with the inner lining layer 1 of the pipeline, the reinforcement layer 2 of the flexible joint is connected with the reinforcement layer 2 of the pipeline, and the reinforcement layer of the flexible joint is connected with the inner lining layer 1 of the pipeline. The protective layer 3 is not provided on the outer side of the layer 2; the reinforcing layer 2 is formed by helically winding the fiber tapes 21, and the reinforcing layer 2 is of at least two-layer structure, and the adjacent layers of the fiber tapes 21 are spirally wound in opposite directions.

The filling layer 22 is arranged between the adjacent layers of the reinforcing layer 2, and the filling layer 22 is composed of an elastic material that can be extruded and deformed. The filling layer 22 deforms and fills the gaps between the fiber strips 21 , and transfers the internal pressure of the pipeline to the outer fiber strips 21 layer by layer.

The fiber tape 21 exceeds the end of the inner lining layer 1 by a certain distance, and the distance is more than 0.5 times the inner diameter of the inner lining layer 1; The adhesive 212 of the windings 211 is located close to the inner side of the pipe or at the adjacent parts between the windings 211 . This arrangement can reduce the flexural section coefficient of the helical winding of the fiber tape 21, so that the fiber tape 21 can be wound more softly and is easy to fit.

The winding wire 211 is made up of at least three fiber bundles 2111 spirally wound with each other, and the twist of each fiber bundle 2111 of the winding wire 211 is the same and greater than zero. Using the fiber bundles 2111 to prepare the windings 211 can make the windings 211 thicker, so that the fiber tapes 21 are thicker, which facilitates the winding of pipes and facilitates butt joint construction of pipes. In addition, the twist of the fiber bundle 2111 is greater than zero, which can increase the fatigue resistance of the fiber.

The helical winding directions of the fiber bundles 2111 of the windings 211 of adjacent layers are opposite to each other. In this way, the shear stress between the windings 211 can be weakened.

An inner core 2112 is provided at a middle position inside the winding 211 , the cross section of the inner core 2112 is circular or annular, and the inner core 2112 is made of elastic material. The inner core 2112 is deformed under pressure, so that the fiber bundles 2111 can be freely stretched to a certain extent, which is convenient for the fiber tapes 21 to fit tightly and transmits the internal pressure of the pipeline.

The filling layer 22 has a belt-like structure and is spirally wound into a cylindrical shape. This arrangement facilitates the winding and installation of the filling layer 22 . During the pipe butting process, the reinforcing layer 2 is wound layer by layer, and the filling layer 22 is added spirally to space the adjacent fiber tapes 21 of the reinforcing layer 2 .

The filling layer 22 is made of rubber material. The filling layer 22 is freely deformed to fill the gap between the reinforcing layers 2 , so as to facilitate the transfer of the internal pressure to the outer layer of the reinforcing layer 2 .

The inner layer fiber belt 21 of the flexible joint is long, and the outer layer fiber belt 21 is short, and the length gradually decreases from the inner layer to the outer layer fiber belt 21 . In the process of pipeline docking, after the inner lining layer 1 is welded, the reinforcement layer 2 is wound and connected layer by layer; the gradual transition from the inner layer to the outer reinforcement layer 2 is conducive to its stress.

The single reinforcing layer 2 of the flexible joint is formed by helically winding a fiber tape 21 . It is convenient for the flexible joint to be connected and installed, and it is more convenient to wind the reinforcing layer 2 layer by layer.

Also includes a wedge-shaped ring 4, the wedge-shaped ring 4 is arranged at the end of the fiber band 21, the wedge-shaped ring 4 is a split ring, the wedge-shaped ring 4 is composed of a compressible and deformable elastic material, and the annular section of the wedge-shaped ring 4 is wedge. Since the fiber tapes 21 are thick, the wedge-shaped ring 4 is provided at the transition portion between the fiber tapes 21, which is conducive to the stress between the layers and avoids stress concentration. The wedge ring 4 is provided as a split ring, which is convenient for its installation during the docking process.

Embodiment 1

The inner diameter of the inner lining layer 1 is 800mm, the inner lining layer 1 is made of polyethylene pipe with a wall thickness of 26mm, the reinforcement layer 2 is selected from aramid fiber, the reinforcement layer 2 contains 8 layers of fiber tapes 21 with a total thickness of 30mm, and the reinforcement layer 2 fiber tapes 21 Winding direction The included angle with the axis of the pipeline is 55°, and between the adjacent layers of the reinforcing layer 2, the fiber tapes 21 are wound in opposite directions. The overlapping length of the innermost layer of fibers at the joint part is 1300mm, the overlapping length of the outermost layer of fibers is 900mm, and the overlapping lengths of the middle layers are evenly transitioned. After the reinforcing layer 2 is wound layer by layer, the filling layer 22 is formed by spirally winding the rubber tape between the layers, and the outer side of the joint is wound with polyethylene tape as the protective layer 3, and the thickness of the protective layer 3 is about 4 mm.

In the pipeline connection, the inner lining layer 1 is first welded, and then the reinforcing layer 2 is wound layer by layer. Through experiments and finite element analysis based on the Tsai-Wu criterion, the burst pressure of the pipeline described in Embodiment 1 is close to 37MPa, the strength of the joint is much higher than the strength of the pipeline itself, and the fiber strain of each layer of the joint changes uniformly and slowly, and the stress state good. (1) According to the existing metal joint structure, the simulation analysis is carried out, and displacement constraints are imposed on the lining layer 1 at the joint part, and a uniform pressure load of 1.8MPa is applied to the outer side of the protective layer 3; the analysis shows that the burst pressure of the pipeline is about 25MPa, and the damaged part is It is concentrated on the metal buckle; the technical solution of the utility model increases the pressure bearing capacity of the pipe joint by about 48%, and avoids the contact between the medium in the pipe and the metal joint. (2) According to the analysis of the existing welded joints, a cylindrical rigid sleeve is set on the outside of the protective layer 3, and the same lining layer as the protective layer 3 is set in the rigid sleeve, and the welding length at both ends of the joint is 200mm; the analysis found that the internal pressure of the pipeline When it reaches 9 MPa, the joint fails to pull out.

Summary: Through the solution of the present invention, the problem of stress concentration of the reinforcement layer 2 caused by the metal joint is avoided, and the problem of insufficient strength of the welded joint is solved. Through the technical scheme of the utility model, the large-diameter high-pressure fiber-reinforced flexible composite pipes can be effectively and high-strengthly connected to meet the needs of oil and gas pipeline transportation and other application occasions.

Claims (9)

1. Flexible joint of flexible compound pipe of heavy-calibre high pressure fiber reinforcement, including inner liner, enhancement layer, filling layer, its characterized in that:

the inner liner layer of the flexible joint is connected with the inner liner layer of the pipeline, and the reinforcing layer of the flexible joint is connected with the reinforcing layer of the pipeline; the reinforced layer is formed by spirally winding fiber tapes, the reinforced layer has a structure of at least 2 layers, and the spirally winding directions of the fiber tapes of adjacent layers are opposite;

the filling layer is arranged between the adjacent layers of the reinforcing layer and consists of elastic materials which can be extruded and deformed;

the fiber belt exceeds the end part of the lining layer for a certain distance, and the distance is more than 0.5 time of the inner diameter of the lining layer; the fiber tape is formed by adding adhesive to at least 2 winding wires side by side for bonding, and the adhesive of the winding wires is close to the inner side of the pipeline or is positioned at the adjacent part between the winding wires.

2. The flexible joint of a large-caliber high-pressure fiber-reinforced flexible composite pipe according to claim 1, wherein: the winding is formed by at least 3 fiber bundles which are mutually spirally wound and woven, and the twist of each fiber bundle of the winding is the same and is more than zero.

3. The flexible joint of a large-caliber high-pressure fiber-reinforced flexible composite pipe according to claim 2, wherein: the fiber bundles of adjacent layers of windings are spirally wound in opposite directions.

4. The flexible joint of a large-caliber high-pressure fiber-reinforced flexible composite pipe according to claim 2, wherein: an inner core is arranged in the middle of the inside of the winding, the section of the inner core is circular or annular, and the inner core is made of elastic materials.

5. The flexible joint of a large-caliber high-pressure fiber-reinforced flexible composite pipe according to claim 1, wherein: the filling layer is of a strip-shaped structure and is spirally wound into a cylindrical shape.

6. The flexible joint of a large-caliber high-pressure fiber-reinforced flexible composite pipe according to claim 1, wherein: the filling layer is made of rubber materials.

7. The flexible joint of the large-caliber high-pressure fiber-reinforced flexible composite pipe according to claim 1, wherein: the flexible joint has a long inner layer fiber band and a short outer layer fiber band, and the lengths of the inner layer fiber band and the outer layer fiber band are gradually reduced.

8. The flexible joint of a large-caliber high-pressure fiber-reinforced flexible composite pipe according to claim 1, wherein: the single reinforcement layer of the flexible joint is formed by spirally winding a fiber band.

9. The flexible joint of a large caliber high pressure fiber reinforced flexible composite pipe of claim 1 further comprising a wedge ring, wherein: the wedge-shaped ring is arranged at the end part of the fiber band, the wedge-shaped ring is an open ring and is made of elastic materials capable of compressing and deforming, and the circumferential section of the wedge-shaped ring is wedge-shaped.

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