RU2718473C1 - Method for continuous production of a multilayer polymer reinforced pipe and a line for realizing the method - Google Patents

Abstract

FIELD: manufacturing technology.

SUBSTANCE: group of inventions relates to a method for continuous production of a multilayer reinforced polymer pipe and a line for its implementation and relates to the oil and gas industry, is intended for construction of underground and ground pipeline systems, providing transportation of products of oil wells and water lines, in particular oil, water, gas, chemical reagents, by means of pipelines based on long polymer pipes. Method for continuous production of a multilayer reinforced polymer pipe by extrusion involves forming an inner layer of a pipe from a polymer melt, which extends from the extrusion head into a molding cavity, application of metal frame formed on the inner layer by welding of longitudinal and transverse reinforcement at their mutual intersection, synchronized with moment of current pulse supply to welding roller electrodes, and application of polymer melt on metal frame to make outer shell of pipe. At that, forming cavity for production of inner layer of pipe is formed between mandrel and applied welded metal frame with cell size, preventing polymer melt outlet beyond forming cavity, due to supply of additional longitudinal wires and reduction of winding pitch of transverse wires. Clamping of welding electrodes to transverse wire in places of its mutual intersection with longitudinal wire is provided with eccentric lever. Line for continuous production of multilayer polymer reinforced pipe includes extruder with extrusion head for supply of polymer melt into forming cavity for forming of inner layer of pipe, welding machine with welding unit serving for production of reinforcing metal frame by welding of longitudinal and transverse wire and containing roller electrodes connected with clamping device and corresponding drive. Behind welding machine there installed is additional extruder with angular extrusion head for application of polymer material for pipe outer shell on metal reinforcing carcass of melt. At that, in the welding unit the roller electrodes equipped with the cooling system are connected to the eccentric lever, which carries the electrodes when welding the transverse and longitudinal wires at their mutual intersection.

EFFECT: technical result, to which the group of inventions is aimed, consists in improvement of operational properties of the manufactured pipe due to reduction of residual stresses, as well as optimization of the manufacturing process and improvement of technological effectiveness of the pipe.

3 cl, 3 dwg

Description

The claimed invention relates to the oil and gas industry, is intended for the construction of underground and above-ground pipeline systems for transporting products of oil wells and water pipes, in particular, oil, water, gas, chemicals through pipelines based on long polymer pipes.

A polymer reinforced pipe is known from the prior art, consisting of an inner polymer layer constituting the base of the pipe, on the outer surface of which a reinforcing layer, an intermediate polymer sheath, is sequentially applied, twisted from insulated conductors having an additional outer sheath in the form of a ring sector bounded by an inner and outer radius laying of conductors, and the outer polymer shell, while the reinforcing layer is made of coils of metal or polymer tapes, polymer threads or allicheskih wires (patent RU №2665776 the invention "polymeric tube reinforced with electrically" filing date of 26.05.2017, published on 04.09.2018 g).

A method of manufacturing a polymer pipe is that the polymer inner layer is fed into the winding unit of the polymer tape coils, in which the external surface of the inner layer of the polymer pipe is coated with four polymer tape coils, for example, of polyethylene terephthalate by winding using a twisting machine, at a tape winding angle, component 55 ± 5 °. When winding polymer tapes, at least one coil has the opposite direction of winding. The windings of polymer ribbon tapes are carried out in such a way that a gap of 5-10% of the tape width is made between the polymer tapes of each coil, and the gap below the wound coil is closed above the wound coil. Reinforcing elements of polymer filaments or metal wires are wound with at least two strands. An intermediate sheath is applied by extrusion over the coils of reinforcing elements, after which the pipe is fed into the coils winder from insulated conductors. Then the polymer pipe with the deposited layers is fed into the extruder for applying the outer polymer shell, in which by means of extrusion a continuous polymer layer is applied, for example from polyethylene, forming the outer shell of the polymer pipe. In the final operation, a flexible polymer reinforced pipe containing 4 coils of polymer tapes, coiled from insulated conductors and the outer polymer shell is wound into a bay or onto transport drums.

A polymer pipe is known that contains an inner layer, a reinforcing layer in the form of a reinforcing element helically wound on the inner layer, and an outer layer, while the reinforcing element is made in the form of a reinforcing mesh of threads bonded at the intersection and the polymer layer in contact with the mesh (patent No. 125668 for the utility model "Polymer pipe", submission date 08.21.2012, published 03.10.2013).

The specified polymer pipe is produced as follows. Granular raw materials are fed into the extruder. In the nozzle head, the plasticized material coming from the main extruder is divided into two streams. In the first nozzle head, a tape is formed - the base of the inner layer. In the second nozzle head, a tape is formed for the outer layer. The rotating drum is preheated, after which it is applied to the inner layer by winding at an angle of -84 °. It is possible to apply the inner layer to the drum by direct extrusion. Then, with the help of an unwinding machine, a reinforcing mesh is laid on the inner layer, on which a finishing composition can be previously applied. The grid is closed from above by the polyolefin melt, then a second layer of the grid can be applied, which is also closed by the polyolefin melt. A polypropylene support hose in a sheath or a layer of a smooth tape profile from a mineral-filled composition of a thermo- and light-stabilized propylene copolymer is applied onto the polymer layer by winding. The reinforcing mesh is laid with an interference fit, which is necessary to ensure the monolithic structure.

The closest technical solution to the claimed is a group of inventions "Method for the continuous production of reinforced metal-reinforced pipes and devices for its implementation" according to patent RU No. 2492047 (filing date 03/14/2012, published September 10, 2013).

The known method includes feeding the polymer melt from the extrusion head into a forming cavity formed by a cooled mandrel and an external forming sleeve, while simultaneously supplying a welded reinforcing cage to said cavity. When forming a pipe, a heat-resistant non-metallic sleeve is installed in front of the mandrel, and the internal and external surfaces of the pipe being molded are cooled. In the manufacture of a reinforcing carcass, a roller electrode is used as a means for forming a spiral from the elements of the transverse reinforcement, the roller of which provides constant clamping of the elements of the transverse reinforcement to the elements of the longitudinal reinforcement with the force from the hydraulic drive. During welding of the reinforcing cage, shock pulses are transmitted to the roller electrode, synchronized with the moment the longitudinal and transverse reinforcement elements intersect with each other, as well as with the moment the current pulse is applied to the roller electrode.

The disadvantages of the known solutions are due to the presence of residual stresses that arise due to frictional forces during the passage of the polymer melt, first through the channel of the extrusion head, and then inside the forming cavity. In addition, the resulting stresses are stored in the polymer matrix of the pipe as a result of constant cooling of the mandrel, which forms, together with the outer sleeve, the specified forming cavity. Residual stresses lead to a violation of the macrostructural orientation of the polymer and, as a result, a decrease in the life of the multilayer pipe.

In addition, in the forming cavity when applying the reinforcing mesh frame to the polymer matrix formed from the melt coming from the extrusion head, the polymer is partially extruded through the cells of the metal frame, which leads to surface defects of the pipe and reduces its operational properties, including strength.

In addition, the disadvantages of the known solutions are associated with the low manufacturability of the polymer pipe due to the need for strict observance of the gaps between the windings of reinforcing tapes or threads, as well as the angle of inclination of the winding.

The concentricity of the inner and outer circumferences of the pipe depends on the accuracy of the relative position of the mandrel, the reinforcing cage, and the forming sleeve, and if the tolerance is exceeded, the reinforcing cage of the pipe is displaced and, as a result, the polymer is insufficiently filled, which leads to defects in the pipe surface and reduces its operational properties, including strength.

The technical result, which the group of inventions aims to achieve, is to increase the operational properties of the manufactured pipe by reducing residual stresses, as well as optimizing the manufacturing process and improving the manufacturability of the pipe.

The specified technical result is achieved in that a method for the continuous production of a multilayer polymer reinforced pipe by extrusion, comprising forming the inner layer of the pipe from a polymer melt exiting the extrusion head into the forming cavity, applying a metal frame formed on the inner layer by welding longitudinal and transverse reinforcement in the moment of their mutual intersection, synchronized with the moment of applying a current pulse to the welding roller electrodes, and deposition on a metallic the first frame of the polymer melt to form the outer shell of the pipe, according to the invention, the forming cavity into which the polymer melt enters to form the inner layer of the pipe is formed between the mandrel and the welded metal frame applied with a mesh size that prevents the polymer melt from leaving the forming cavity by supplying additional mineral-filled composition of thermo- and light-stabilized propylene copolymer. The reinforcing mesh is laid with an interference fit, which is necessary to ensure the monolithic structure.

The closest technical solution to the claimed is a group of inventions "Method for the continuous production of reinforced metal-reinforced pipes and devices for its implementation" according to patent RU No. 2492047 (filing date 03/14/2012, published September 10, 2013).

The known method includes feeding the polymer melt from the extrusion head into a forming cavity formed by a cooled mandrel and an external forming sleeve, while simultaneously supplying a welded reinforcing cage to said cavity. When forming a pipe, a heat-resistant non-metallic sleeve is installed in front of the mandrel, and the internal and external surfaces of the pipe being molded are cooled. In the manufacture of a reinforcing carcass, a roller electrode is used as a means for forming a spiral from the elements of the transverse reinforcement, the roller of which provides constant clamping of the elements of the transverse reinforcement to the elements of the longitudinal reinforcement with the force from the hydraulic drive. During welding of the reinforcing cage, shock pulses are transmitted to the roller electrode, synchronized with the moment the longitudinal and transverse reinforcement elements intersect with each other, as well as with the moment the current pulse is applied to the roller electrode.

The disadvantages of the known solutions are due to the presence of residual stresses that arise due to frictional forces during the passage of the polymer melt, first through the channel of the extrusion head, and then inside the forming cavity. In addition, the resulting stresses are stored in the polymer matrix of the pipe as a result of constant cooling of the mandrel, which forms, together with the outer sleeve, the specified forming cavity. Residual stresses lead to a violation of the macrostructural orientation of the polymer and, as a result, a decrease in the life of the multilayer pipe.

In addition, in the forming cavity when applying the reinforcing mesh frame to the polymer matrix formed from the melt coming from the extrusion head, the polymer is partially extruded through the cells of the metal frame, which leads to surface defects of the pipe and reduces its operational properties, including strength.

In addition, the disadvantages of the known solutions are associated with the low manufacturability of the polymer pipe due to the need for strict observance of the gaps between the windings of reinforcing tapes or threads, as well as the angle of inclination of the winding.

The concentricity of the inner and outer circumferences of the pipe depends on the accuracy of the relative position of the mandrel, the reinforcing cage, and the forming sleeve, and if the tolerance is exceeded, the reinforcing cage of the pipe is displaced and, as a result, the polymer is insufficiently filled, which leads to defects in the pipe surface and reduces its operational properties, including strength.

The technical result, which the group of inventions aims to achieve, is to increase the operational properties of the manufactured pipe by reducing residual stresses, as well as optimizing the manufacturing process and improving the manufacturability of the pipe.

The specified technical result is achieved in that a method for the continuous production of a multilayer polymer reinforced pipe by extrusion, comprising forming the inner layer of the pipe from a polymer melt exiting the extrusion head into the forming cavity, applying a metal frame formed on the inner layer by welding longitudinal and transverse reinforcement in the moment of their mutual intersection, synchronized with the moment of applying a current pulse to the welding roller electrodes, and deposition on a metallic the first frame of the polymer melt to form the outer shell of the pipe, according to the invention, the forming cavity into which the polymer melt enters to form the inner layer of the pipe is formed between the mandrel and the welded metal frame applied with a mesh size that prevents the polymer melt from leaving the forming cavity by supplying additional regulation and changes in the properties of the pipe, taking into account the specified parameters and conditions of its operation.

Next, a cooling bath 25 is installed, after which a pulling device 26 with adjustable clamping force of the tracks 27, a cutting device 28 with a position sensor 29, mounted on the roller table 30 are arranged in series.

The invention is as follows.

A multilayer reinforced pipe is obtained by extrusion molding, in which the polymer melt intended for forming the inner layer - the liner from the extruder 10 enters the direct-flow extrusion head 11, passes through its channel connected to the forming cavity, which is formed by a continuously cooled mandrel and a supplied reinforcing metal frame welded in the form of a dense grid with the smallest reduced cell size.

The reinforcing metal frame is made of metal longitudinal and transverse wires that are welded in places of their mutual intersection. A dense reinforcing cage is formed by supplying additional (increasing the number) of longitudinal wires and decreasing the step of winding spiral wires. Due to this, an almost monolithic metal frame is formed without cells, which creates obstacles for the molten polymer material to exit, i.e. outside the frame.

The formation of the forming cavity between the mandrel and the reinforcing frame allows to reduce the trajectory of the melt and, accordingly, to reduce the effect of friction forces, due to which the residual stresses in the polymer matrix are significantly reduced, which, in turn, increases its operational properties.

In addition, the need for strict observance of the exact relative position of the structural elements forming the forming cavity is eliminated.

In addition, the process of manufacturing a multilayer pipe is optimized.

On the mandrel, the inner diameter of the liner is calibrated.

As the liner cavity is filled with cooling fluid, pressure is created in it, which is maintained by a drain valve located in the plug installed at the end of the tube passing inside the direct-flow head.

The reinforcing frame is formed by winding spiral wires 7 on the longitudinal 5 and welding together at each point of their intersection. The tension and movement of the longitudinal wires 5 is carried out by means of a pulling device 26, while the geometrical position of the longitudinal wires relative to the pipe body is determined by concentrically arranged grooves on the conductor 12. The outer spiral of the reinforcing frame is formed due to the simultaneous supply of the spiral wire 7 coming in when the rotor 17 of the welding machine 9 rotates. , and translational movement of the longitudinal wires 5. The winding spiral wire 7 is welded to the corresponding sequentially the longitudinal wires 5 that are contacting it using at least two roller electrodes 21. The helical wire 7 is wound from the drums of the welding machine 9 located on the rotor body 17 and freely rotating on bearings, and fed to the welding roller electrodes 21 using a feed mechanism wire from the drum of the welding machine to the spiraling machine 18 and spiraling machines 19. The eccentric lever 22 presses the roller electrodes 21 to the spiral wires 7, while the welding electrodes are pressed and the welding pulse is applied of current for welding pin, made at the same time. The moment of supplying welding current pulses from transformers (not shown in the drawing) to the welding roller electrodes is carried out using the knob 31. Then, the polymer melt is formed for forming the liner, then to the reinforcing frame in the corner forming cavity, is fed into the forming cavity formed by the mandrel and the welded reinforcing cage extrusion head 24 is applied to the polymer melt to form the outer shell of the pipe.

After that, the polymer reinforced pipe 32 is subjected to intensive cooling in the cooling bath 25 by supplying atomized coolant through nozzles made along the entire length of the bath to the outer surface of the pipe.

After exiting the bath 25, the multilayer reinforced pipe passes the pulling device 26 and then enters the roller table 30, which moves thanks to the guide rollers. At the same time, the roller table serves as a support for the finished product. The design of the roller table provides a system for collecting coolant and returning it to the cooling system.

The location of the position sensor 29 on the roller table is determined depending on the length of the produced multilayer reinforced pipe 32.

The signal from the sensor 29 is fed to a cutting device 28, which moves simultaneously with the pipe along the guides, operates and cuts off the pipe of a given length.

The whole process is continuous and cyclical.

The implementation of the invention is confirmed by examples of specific performance.

The operation parameters of pipelines made of a multilayer polymer reinforced pipe are designed for the temperature of the transported medium up to + 80 ° С and the working pressure of the pipeline up to 4.0 MPa.

The polymeric multilayer reinforced pipe in accordance with the invention proposed for protection is produced by extruding the inner layer - the liner, while reinforcing it with a metal frame and then applying a melt on it to form an outer shell.

The liner is made of, for example, polyethylene of minimum long-term strength MRS 10.0 MPa (PE 100) or polyethylene of increased heat resistance of minimum long-term strength MRS 10.0 MPa (PE-RT type II) or an oil-resistant polymer, in particular polyamide: PA 12; PA 11, PA 6.10; PA 6.12.

For the manufacture of a reinforcing metal mesh frame that accepts both axial and radial loads arising from the operation of pipelines, steel wire of general purpose, thermally untreated with a diameter of 2.5 to 4.0 mm, supplied without lubrication in accordance with GOST 3282-74 “Wire steel low-carbon general purpose. Technical conditions. " The formation of the reinforcing metal frame is performed using a welding unit. The cell size in the light is 2 × 2 mm.

The outer shell of the polymer multilayer reinforced pipe protects the reinforcing cage from damage and environmental influences. The shell, like the liner, is extruded with polyethylene of minimum long-term strength MRS 10.0 MPa (PE 100) or polyethylene with increased heat resistance of minimum long-term strength MRS 10.0 MPa (PE-RT type II). Alternatively, a flame retardant composition, for example, based on polyethylene, can be used as the material for the outer shell.

As oil-resistant polymers, for example, structural thermoplastic polyamides can be used: either PA 12 (polydecodanamide), or PA 11 (polyundecanamide), or PA 6.10 (polyhexamethylmenesebacinamide), or PA 6.12 (polyhexamethyleneendodecandiamide).

For the manufacture of the inner layer - the liner and the outer shell, various materials can be selected with, respectively, different properties.

The claimed group of inventions allows to obtain a multilayer polymer reinforced pipe of increased strength, reliability and manufacturability.

Claims (3)

1. A method for the continuous manufacture of a multilayer polymer reinforced pipe by extrusion, comprising forming the inner layer of the pipe from the polymer melt emerging from the extrusion head into the forming cavity, applying a metal frame to the inner layer formed by welding longitudinal and transverse reinforcement at the moment of their intersection, synchronized with the moment a current pulse is applied to the welding roller electrodes, and applying a polymer melt to the metal frame to perform an external pipe bolts, characterized in that the forming cavity into which the polymer melt enters to obtain the inner layer of the pipe is formed between the mandrel and the welded metal frame applied with a mesh size that prevents the polymer melt from leaving the forming cavity by supplying additional longitudinal wires and reducing step of winding the transverse wires, while the pressure of the roller welding electrodes to the transverse wire at the points of its intersection with the longitudinal wire is provided exce serge lever associated with roller electrodes. 2. The method according to p. 1, characterized in that the polymers use oil-resistant polymers, such as polyamides. 3. A line for the continuous production of a multilayer polymer reinforced pipe for the method according to claim 1, including an extruder with an extrusion head for feeding the polymer melt into the forming cavity for forming the inner layer of the pipe, a welding machine with a welding unit, which serves to obtain a reinforcing metal frame by longitudinal welding and a transverse wire and containing roller electrodes associated with the clamping device and the corresponding drive, characterized in that the forming cavity into which the polymer melt for the inner layer of the pipe is created between the mandrel and the metal frame being welded, an additional extruder with an angular extrusion head is installed behind the welding machine for applying molten polymer material intended for the outer shell of the pipe to the metal reinforcing frame, while in the welding unit there are roller electrodes equipped with cooling system, connected to an eccentric lever, which clamps the electrodes when welding the transverse and longitudinal wires at the moment of their mutual eresecheniya.

Images