RU2222746C2 - Method of mounting sleeve onto defective part of pipeline - Google Patents

Abstract

FIELD: construction engineering. SUBSTANCE: invention is designed for use in repair of pipelines of different application. According to proposed method, section of pipeline to be repaired is cleaned, at least 4 coils of wire are turned onto cleaned section and connected by tack welds. Layer of sealant is applied to cleaned section and wire members and split sleeve is fitted on wire members. Wire is annealed prior to winding onto pipeline. Diameter of wire is chosen depending on viscosity of sealant. Sealant is fed between sleeve and pipeline. EFFECT: improved reliability of high-pressure pipelines. 5 cl, 3 tbl, 1 dwg

Description

 The invention relates to the repair of pipeline transport and can be widely used in gas, oil and other industries.

 The invention can be used in the repair of pipelines for various purposes, having unacceptable defects in ring welded joints with significant corrosion damage to the pipe wall in adjacent areas.

 A known method of attaching process elements to a pipeline under pressure. The method includes installing rings, assembling a technological element (tee, coupler) from two or more parts, fixing and welding these parts together with rings, and filling the cavity between the pipeline and the technological element with a gas-tight mass (sealant).

 In order to improve the quality and reliability of the welded unit and reduce the risk of destruction during the welding of technological elements to pipelines having reinforcements of circumferential seams, one ring is made with an annular groove in which the reinforcement of the circumferential seam of the pipeline is located, and the technological element is welded directly to the rings without penetration of the wall pipeline (see AS USSR 1199546, MKI B 23 K 31/06,).

 However, this method does not provide reliable quality of sealing the pipeline.

 A known method of temporarily blocking the flow from a damaged pipe (see AS USSR 1681130, MKI F 16 L 55/168, publ. Bull. 36 from 09/30/91).

 A known method of eliminating damage in oil pipelines, including cleaning the outer surface of the damaged place, applying an adhesive composition to it and gluing insulating material (see Russian patent 2011106, MKI5 F 16 L 55/17 from 10/19/90).

 To expand the operational ability to eliminate leaks and increase the tightness and mechanical strength of the insulation, a layer of adhesive composition is applied to the cleaned surface of at least 120 mm on both sides of the welding joint; after that, 10-15 mm to the left and right of the welded joint on the adhesive, the pipeline is tightly wrapped twice with soft iron or aluminum wire with a diameter of 2.5-3 mm, covering the body along the length of the pipe at least 100 mm, while the wire of the second row of windings are placed in the recess between the turns of the wire of the first row, then the welded joint and the unwound part of the pipe between the wire windings on the glue are tightly wrapped with a rope winding, impregnated with the same glue, to the level of the outer surface of the second row of the wire winding, after which otannoe place adhesively wrapped with two rows of the same wire, which overlap the coil former and a welded joint, with the same number of subsequent wire winding planted in the recesses between the turns of the wire of the previous row.

 The pipeline overhaul technology is widely known by installing a repair sleeve filled with epoxy. The repair sleeve is used to repair and strengthen damaged pipelines without disrupting product flow. Each repair structure consists of two coupling halves, the dimensions of which exceed the diameter of the section being repaired. The coupling halves are mechanically connected together and completely encircled the damaged part of the section. The coupling halves are installed on the technological elements. An epoxy solution (sealant) is pumped into the annular space between the repaired section and the coupling halves, which provides a high degree of rigidity of the repair structure. As a result, the repaired section of the section has higher strength than the adjacent intact pipe. Epoxy-coupling technology is used to repair all types of non-through defects in pipelines operating under high pressure (see, for example, British Gas Advertising (British Gas р / с Ripley Road, Ambergate, Derbyshire, DE 562 FZ).

 The specified method is selected as a prototype.

 However, this method involves significant work on the alignment of the coupling on the damaged section of the pipeline.

 The basis of the invention is the task to develop such a method of installing the coupling on the defective section of the pipeline by means of a new sequence of technological operations that will increase the reliability of sealing and provide acceleration of the installation of the coupling on the defective section of the pipeline.

 This problem is solved in that in the known method, including the manufacture and installation of technological elements on a cleaned section of the pipeline, on which a sleeve of two halves is installed, followed by welding of these halves with longitudinal seams and filling the space between the sleeve and the damaged portion of the pipeline with a sealant, the technological element is made of wire, which is wound on the pipeline on both sides of the damaged area. Before winding the wire, the wire is annealed in the furnace and at least 4 turns are wound on both sides of the damaged section of the pipeline. The wire is interconnected by welded tacks, while the diameter of the wire is selected in the range of 1.6 - 6.0 mm depending on the viscosity of the sealant, and the width of the technological elements from the wire is selected at least 20 mm.

 The method is illustrated in the drawing.

 The defective section of the pipeline 1 is protected from the insulation coating, rust and dirt. On both sides of the defective section of the pipeline 1, at least 4 turns of wire 2 are wound onto the pipeline and are joined together by welded tacks. In order for the wire 2 to be soft, it is annealed in a furnace before being wound onto the pipe 1. The diameter of the wire is selected in the range of 1.6-6.0 mm, depending on the viscosity of the sealant. The width of technological elements made of wire should not exceed 20 mm. On the wire 2, wound on the pipe 1, install two coupling halves 3, 4, which are welded together (longitudinal seams). A sealant is fed into the space between the coupling and the pipe 1 through the nipple 6, which, after hardening, forms a sealed coating 7 on the damaged surface of the pipe 1. Before being fed into the space between the pipe 1 and the sealant, the ends of the coupling are sealed with a quick-hardening composition, for example, epoxy resin, 8 .

 An example implementation of the method.

 As a result of in-line diagnostics of the main pipeline DN 1400x18 mm from steel grade X70, a defective section was detected. According to regulatory requirements, this section must be cut with the subsequent replacement of the coil with complete emptying and purging of the pipeline. Since the pipeline 1 cannot be taken out of operation, it was decided to reinforce the defective area with a sleeve installed by the proposed method on the pipeline under a pressure of 3.9 MPa.

The surface of the defective section of the pipeline is cleaned of dirt and corrosion products. Four turns of wire 2 and 3 of low-carbon steel sv-08 with a diameter of 5 mm are wound on pipe 1 on both sides of the defective section, while the turns are connected by welded tacks. Before winding, the wire is annealed in a furnace at a temperature of 890-950 ^o С. A split sleeve consisting of two halves 3, 4 of 09G2S steel (having good weldability with a wall thickness of 14 mm) is installed on the wire 2 wound on the pipe 1. The coupling was mounted on wire 2 using fasteners, which allow tightly squeezing half-shells on the wire and perform welding with piece electrodes of type E50A longitudinal welds 7 with full penetration.

 Before applying the sealant to the space between the pipeline 1 and the coupling, the ends of the coupling are sealed with a quick-hardening composition, for example, epoxy resin, 8.

After welding, an epoxy-based sealant is pumped into the space between the pipe 1 and the socket through the nipple 6. Air is removed from the cavity through openings in the upper coupling half. In order to accelerate the polymerization of the sealant, apply the heating of the coupling surface to a temperature of 80-100 ^o C.

 For high-quality filling of the space between the pipe 1 and the sealant sleeve, the nipple 6 in the upper and lower coupling halves are offset relative to each other.

 The table shows the results of a number of studies related to the application of this method.

 The results of experimental verification showed that the method provides complete sealing of the damaged section of the pipeline.

 If the requirements for the technological gap between the sleeve and the pipeline (wire diameter) are not met, a specific adhesive coating with a certain viscosity does not provide a high-quality coating of the damaged section of the pipeline with sealant.

Claims (5)

1. The method of installing the coupling on the defective section of the pipeline, including installing a split coupling on the technological elements, cleaning the area before installing the coupling, applying a layer of sealant to the cleaned area, characterized in that the technological elements are made of wire that is wound on the pipeline for at least 4 turns and connect the turns together with welded tacks. 2. The method according to claim 1, characterized in that the wire is annealed before winding onto the pipeline. 3. The method according to claim 1 or 2, characterized in that the sealant is served between the sleeve and the pipe. 4. The method according to claim 1, characterized in that the width of the technological elements from the wire that is wound onto the pipeline should be at least 20 mm. 5. The method according to claim 1, characterized in that the wire diameter is selected depending on the viscosity of the sealant composition.

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