RU2245481C1 - Joint for polymeric reinforcing pipes - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: cylindrical spaces of the housing made of monolithic polymeric unit receives the ends of pipes to be joined abut, e.g., by welding. The polymeric unit houses movable reinforcing frame with longitudinal members and heating members arranged from the side of inner surfaces of the spaces. The housing is made of a bushing made of polymeric material provided with radial projections on the faces. The longitudinal members of the reinforcing frame are made of fibers winding along the longitudinal axis of the bushing between the radial projections of the bushing faces and are set in the monolithic polymeric unit.

EFFECT: expanded functional capabilities.

4 cl, 4 dwg

Description

The invention relates to the field of construction of pipelines intended for the transportation of liquid or gaseous, including chemically aggressive, media at overpressure and temperature fluctuations, and more particularly to connecting elements of pipelines.

A known connecting element for connecting the ends of the pipes to each other (1), made in the form of a coupling, which is a housing with cylindrical cavities for the ends of the pipes to be joined, the housing is made of thermoplastic material, inside of which is placed a reinforcing layer containing continuous tubular reinforcement and heating element made in the form of a spiral. The fitting of the coupling has a higher rigidity than the rigidity of a thermoplastic material and is designed to absorb welding pressure during welding.

The cylindrical shape of the cavities makes it possible to use this coupling to connect the ends of the pipes only if the latter can be heard during welding heating, i.e. increase in outer diameter by the amount of technological gaps between the mounting cylindrical cavity of the coupling and the outer surface of the connected end of the pipe. The presence of rigid continuous reinforcement in the body of the connecting element makes it impossible to use this coupling for connecting pipes with high rigidity, i.e. during the construction of heavily loaded pipelines from reinforced polymer pipes, as Neither the coupling nor the connected pipes can change the size of the seating surfaces during the welding process to ensure a tight, reliable connection.

A known coupling for connecting polymer pipes (2), comprising a housing with conical cavities for the ends of the pipes to be connected, a heating element mounted in it on the side of the inner surfaces in the form of a spiral, and a continuous tubular perforated frame placed in a polymer monolith, the rigidity of which is not less than the reinforcing stiffness the frame of the connected pipes, while the angle of the conicity of the coupling cavities is made no more than the angle of friction of the polymer of the housing and the connected pipes.

This design ensures that the load capacity of the pipeline is equal to the design load capacity of the pipe when the pipes are connected to each other in series. However, the disadvantage of this design is the need to ensure high accuracy matching the taper of the ends of the connected pipes and cavities of the couplings. In addition, in the case of repair of the pipeline and especially when replacing an individual pipe or its section, the use of such couplings is impossible due to the need for axial shift of at least one of the sections of the pipeline under repair by the length of the conical cavity of the coupling.

Thus, when using connecting elements made of a polymeric material and having a cylindrical cavity for the ends of the pipes to be connected, the required load capacity of the pipeline cannot be provided, because joints do not have the required strength to axial and radial loads. In addition, it is impossible to ensure a tight fit of the connecting element due to the stiffness of the reinforcing frame. When using connecting elements with a conical shape of the cavities, technological difficulties arise with the installation of the pipeline and especially with its subsequent repair and maintenance.

A known connecting element of the pipeline (3), the design of which is adopted as a prototype, comprising a housing made of a monolithic polymer block with cylindrical cavities for the ends of the pipes to be connected, inside which a reinforcing cage is placed, and heating elements in the form of conductive spirals are installed on the side of the internal surfaces of the cavities , dividing the inner surface of the cavity into a heating zone and a cold zone, while the reinforcing frame is made perforated in the form of a ring and interacting with their longitudinal perforated elements which are arranged on the ring with the possibility of radial movement and the width of the ring is commensurate with the width of cold zone.

This design simplifies the installation and repair of pipelines while achieving the design load capacity of the pipeline, since it has a movable, i.e. non-rigid reinforcing frame, however technologically difficult to manufacture, requires a large number of individual parts and expensive equipment for their manufacture (stamps, presses, etc.)

In addition, all of the mentioned joints assume a gap between the ends of the pipes to be connected, which results in capillary leakage of the transported medium into the cavity of the coupling, which reduces the loading capacity of the pipeline and requires additional reinforcement of the coupling design over the joint zone, complicates the design and manufacturing process.

The problem solved by the invention is to simplify the design of the connection of polymer reinforced pipes, simplify and reduce the cost of their manufacture while achieving the design load characteristics of the connection.

This problem is solved as follows.

In the known connection of polymer reinforced pipes containing a housing of a monolithic polymer block with cylindrical cavities for accommodating the ends of the pipes to be joined, a movable reinforcing frame with longitudinal elements located in the polymer block and heating elements placed on the side of the internal surfaces of the cavities, ACCORDING TO THE INVENTION, the housing is made in the form bushings of polymer material with radial protrusions at the ends along the outer diameter, while the longitudinal elements of the reinforcing frame are made in the form of the high-modulus fibers wound along the longitudinal axis of the sleeve between the radial protrusions of the ends of the sleeve and are enclosed in a monolithic polymer block, and the ends of the pipes to be joined are butt-fastened, for example, by welding. Washers with radial protrusions on the outer diameter located between the radial protrusions of the sleeve are installed at the ends of the sleeve. Filaments of high modulus fibers are wound in one or more layers parallel to the axis of the sleeve, uniformly along its outer surface, or at an angle to the axis of the sleeve in two or more overlapping layers. Bonding of pipe ends end to end is made on conical surfaces.

Figure 1 shows a General view of the proposed connection of polymer reinforced pipes.

Figure 2 shows a General view of the sleeve with a reinforcing frame in the form of threads of high modulus fibers, wound parallel to the axis of the sleeve.

Figure 3 shows a General view of the sleeve with a reinforcing frame in the form of threads of high modulus fibers, wound at an angle to the axis of the sleeve with the crossing layers.

Figure 4 shows the ends of the pipes in the position before butt welding with tapered abutting surfaces.

The connection of polymer reinforced pipes contains a sleeve 1 of a polymer material, in the cylindrical cavities of which the ends of the connected pipes 2, 3 are placed. The sleeve 1 is equipped with end washers 4 with radial protrusions 5 in outer diameter, which are placed between the radial protrusions 6 made on the ends of the sleeve 1. Between the projections 6 of the sleeve 1 along its axis are wound filaments 7 of high modulus fibers, forming a reinforcing cage and placed in a block of monolithic polymer 8. The filaments 7 are either parallel to the axis of the sleeve 1 in one or several ko layers uniformly on its outer surface, or at an angle to the axis of the insert 1 at two or more crossed layers. Conducting spirals 9 are placed on the inner surfaces of the cavities of the sleeve 1. In the monolith 8, fittings 10 are placed for the current supply to the spirals 9. On the welded ends of the pipes 2, 3 there are made equidistant conical surfaces 11, 12 with an angle of inclination α to the axis of the pipes 2, 3.

Directly connecting element in the form of a sleeve 1 with a monolith 8 is manufactured under stationary production conditions as follows.

At the ends of the sleeve 1, radial protrusions 6 are made, between which end washers 4 are installed with radial protrusions 5 on the outer diameter, then a thread 7 of high modulus fibers is fixed on one of the protrusions 6 and it is wound between the protrusions 6 of the opposite ends of the sleeve 1 along its axis. The winding is carried out in two ways described above. The washers 4 are made of a more rigid material than the sleeve 1, to protect the sleeve 1 from the indentation of the threads 7 at high axial or pulsating loads. The wound yarns 7 form a radially non-rigid reinforcing cage that is poured into the polymer block 8, which is firmly connected to the sleeve 1. On the side of the inner surfaces of the sleeve 1, conductive spirals 9 are introduced.

The connection of polymer reinforced pipes during the installation of pipelines is as follows.

A sleeve 1 with a polymer block 8 is put on one of the connected pipes 2, 3 with a technological gap, then the ends of the pipes 2, 3 are installed in lunettes and conical surfaces 11, 12 are made at their ends, or the ends are prepared for ordinary butt welding. With a conical or flat heater, the abutting surfaces of the ends of the pipes are heated, then the pipes are deposited and the molten surfaces form a strong connection. After holding and cooling the joint, the external burr is cleaned and the sleeve 1 is pulled together with the polymer block 8 over the joint area. Then turn on the heating of the spirals 9 and melt the inner surface of the cavity of the sleeve 1 and the outer surface of the ends of the pipes 2, 3, while there is a strong connection of the ends of the pipes. Since the reinforcing frame of the sleeve 1 is not rigid in the radial direction, the required shrinkage of the sleeve is achieved and the load-bearing capacity of the joint is equal with the pipes 2, 3.

Welding of the joined pipes 2, 3 end-to-end eliminates the penetration of the transported medium into the cavity of the sleeve, and therefore it is not necessary to strengthen its middle part with special elements, which greatly simplifies the design and manufacture of the connection with high strength characteristics. In addition, welding on conical surfaces allows you to strengthen the strength characteristics of the weld of pipes 2, 3, and to facilitate the centering of joined pipes before welding due to their self-centering on conical surfaces, as well as to expand the tolerance range for ovality or ellipse of pipes, since the operation of forming the conicity of the ends made immediately before welding in lunettes. In the case of welding pipe ends on flat surfaces, the trimming process is facilitated, but the bearing characteristic of the seam is underestimated and higher requirements are placed on the centering operation of the joined pipes, since there is no self-centering, the requirements for tolerances on the ellipse and ovality of the joined pipes are also increased to ensure the optimum weld area surface.

SOURCES OF INFORMATION

1. DE patent No. 3932807, MKI F 16 L 47/02, 1991

2. Patent RU No. 2071689, IPC 6 F 16 L 47/02, 1997

3. Patent RU No. 2135879, IPC 6 F 16 L 47/00, 1998 (prototype).

Claims (5)

1. The connection of polymer reinforced pipes, comprising a housing of a monolithic polymer block with cylindrical cavities in which the ends of the pipes to be connected are placed, a movable reinforcing frame with longitudinal elements located in the polymer block, and heating elements placed on the side of the internal surfaces of the cavities, characterized in that the housing is made in the form of a sleeve of polymer material with radial protrusions at the ends, while the longitudinal elements of the reinforcing frame are made in the form of threads of high modulus waves windows, wound along the longitudinal axis of the sleeve between the radial protrusions of the ends of the sleeve, and are enclosed in a monolithic polymer block, and the ends of the connected pipes are butt-fastened, for example, by welding. 2. The connection of polymer reinforced pipes according to claim 1, characterized in that the threads of high modulus fibers are wound in one or more layers parallel to the axis of the sleeve uniformly along its outer surface. 3. The connection of polymer reinforced pipes according to claim 1, characterized in that the threads of high modulus fibers are wound at an angle to the axis of the sleeve in two or more overlapping layers. 4. The connection of the polymer reinforced pipes according to claim 1, characterized in that the end-to-end bonding of the pipes is made on conical surfaces. 5. The connection of polymer reinforced pipes according to claim 1, characterized in that on the ends of the sleeve before winding the reinforcement made of high modulus fibers, washers are installed with radial protrusions along the outer diameter located between the end radial protrusions of the sleeve.

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