RU2141072C1 - Method of coating inner surface of pipe line - Google Patents

Abstract

FIELD: mechanical engineering. SUBSTANCE: auxiliary hose is preliminarily introduced into pipe line and combination hose impregnated with polymer binder is introduced in it by turning it out. This hose is inflated to obtained contact with pipe line and is hardened afterwards. Force of pressing the hose is created by pressure of gas or liquid. EFFECT: avoidance of loss of polymer binder; enhanced reliability of coat due to avoidance of effect of ground water on binder. 4 cl, 3 dwg

Description

 The invention relates to a technology for applying a repair coating to the inner surface of a pipeline and can be used in the repair of pipelines of underground or surface locations.

 The problem of repairing pipelines underground under the "trenchless method" has long been known. In this case, as a rule, a combined sleeve / КР / is used, which is a reinforcing system based on organic or inorganic fibers of a directed or chaotic arrangement, impregnated with a polymer binder. CR is placed in the damaged pipeline by the method of "direct pulling" or hydrostatic "inversion eversion."

 This invention relates to the method of "inversion eversion", in which, in contrast to the method of "direct pulling", the inner surface of the CR in the process of introducing it into the cavity of the defective pipe turns out under the pressure of a gaseous or liquid medium and becomes an external surface, and the external, on the contrary, becomes the inner surface of the CR.

 A known method of applying to the inner surface of the pipeline a flexible lining material, impregnated from the inside with a binder, by introducing it by eversion under the influence of liquid pressure into the pipeline. An additional flexible sleeve having a porous structure and a diameter smaller than the diameter of the main sleeve is attached to the end of the tubular lining material. When the lining sleeve is inverted, the additional sleeve is drawn into the inner part of the pipeline, while the main sleeve is attached to the inner surface of the pipeline using a binder. Then, to accelerate the curing of the binder, a heated gaseous stream is introduced into the additional sleeve, which heats the lining material through the pores of the flexible sleeve / UK patent N 2072300, MKI F 16 L 1/00, 1982 /.

 A disadvantage of the known technical solution is the direct contact of the binder with the wall of the pipe being repaired.

 This circumstance is fraught both with the loss of the polymer binder in the defects of the pipe being repaired, and with the difficulties associated with the instability of the polymerization process itself due to, in particular, the uncontrolled influence of groundwater on this process.

 Known methods of coating the inner surface of the pipeline, which consist in the preliminary manufacture of the lining shell containing the inner and outer film sleeves and the filler placed between them - a reinforcing fiber sleeve impregnated with a thermosetting binder, introducing this shell into the pipeline, pressing it to its walls and subsequent polymerization of the binder RF patents N 2037733, MKI FL 58/10, 1995; 2037420, MKI B 29 C 63/34, 1995 /.

 In known technical solutions, the repair sleeve contains two film sleeves in its structure that reliably protect the sleeve from loss of binder and instability of the polymerization process.

 However, such designs of hoses can only be used when repairing pipes using the “direct pulling” method and for limited / up to 50-70 m / lengths of repaired pipes. Repair of long pipes is not possible due to the high probability of injury to the sleeve when it is placed inside the pipeline due to the fact that the mass of the combined sleeve impregnated with a binder is hundreds of kilograms with a diameter of 300 mm and a length of up to 50 m, and with a diameter of 400-450 mm and 100 mm long - more than 1000 kg.

 The closest in technical essence to the invention is a method of coating the inner surface of the pipeline, which consists in introducing into it a combined sleeve of a composite based on a fiber-impregnated polymer binder with an outer film coating, securing the end of the combined sleeve on the pipeline, unscrewing it and pressing it against the pipe wall under the action of pressure of the medium followed by polymerization / US patent N 4064211, MKI B 29 C 17/00, 1977 - prototype /.

 The disadvantages of the prototype include contact of the composite with the inner surface of the pipe to be repaired with the ensuing consequences indicated above. In addition, under real conditions, the condition of the surface of the pipeline to be coated is such that repeated cleaning by special methods and thorough drying / in the presence of soil moisture / liquid residues in various-sized pipeline defects may be required. This will lead to significant additional labor costs, the availability of special technological equipment and expensive equipment.

 The objective of the present invention is to eliminate the disadvantages of the prototype and to ensure, therefore, the conditions for expanding the technological capabilities of the method for repairing pipes of large dimensions in length and diameter.

 The problem is solved due to the fact that in the known method of coating the inner surface of the pipeline, which consists in introducing into it a combined sleeve of a composite based on a fiber-impregnated polymer binder with an outer film coating, securing the end of the combined sleeve on the pipeline, unscrewing it and pressing it against the wall the pipeline under the action of pressure of the liquid medium and subsequent polymerization, before introducing the combined sleeve into the pipeline in the last place the whole omogatelny sleeve of thermoplastic film.

 In this case, it is advisable to place the auxiliary sleeve in the pipeline by eversion under the pressure of compressed air of 0.1-0.5 ati.

 The polymerization is carried out in a closed volume of a combined sleeve formed by a film coating of a fibrous material and an auxiliary sleeve.

 According to the invention, the coating formation of the inner surface of the pipeline is carried out in two stages. First, the film sleeve is inverted into the pipeline, which significantly expands the technological capabilities of the method, because in this case, the film sleeve is not injured and it can be introduced into the pipeline of larger diameter and greater length. An additional auxiliary sleeve prevents contact of the inner surface of the pipeline with the power layer of the combined sleeve introduced into the pipeline in the second stage, i.e. with composite. Thus, conditions are created for the polymerization of the combined sleeve in a closed volume between two sealed film sleeves.

 The implementation of the method is illustrated by drawings, where in FIG. 1 shows the first stage of the process — insertion of an auxiliary sleeve by eversion; FIG. 2 shows the second stage - the introduction of the main two-layer sleeve by eversion under the action of a column of water, in FIG. 3 shows a fragment of the wall of the repaired pipeline.

 An auxiliary sleeve 2 is introduced into the cavity of the pipeline 1 by eversion from the autoclave 3 under the action of compressed air. Preliminarily, the end of the sleeve 2 is fixed along the ring 4 at the end of the pipeline 1. Then, in a similar manner, but using a column of water 5 from the storage tank 6, a combined sleeve of fibrous material 7 with a thermoplastic coating is introduced 8. The polymerization of the combined sleeve is carried out between the sleeves 2 and 8.

 Examples of the method.

 Example 1

An auxiliary sleeve of a 200 micron thick plastic film was introduced into the pipe to be repaired with a diameter of 600 mm and a length of 100 m. In this case, the end of the auxiliary sleeve was pre-mounted on the pipe in a ring. Inversion of the film sleeve was carried out using an autoclave under the action of a compressed air pressure of 0.1 ati. After the end of the first stage, which was fixed by the appearance of a sleeve at the extreme / right / end of the pipe, the main combined sleeve based on a polyolefin-coated felt was started to be introduced into the last in the same way. The eversion of this sleeve was carried out under the influence of a water column pressure of 3 m high. The polymerization was carried out with the same water, but with its gradual heating from normal temperature to 80 ^o C.

 Example 2

 It was carried out analogously to example 1, but a pipe with a diameter of 450 mm and a length of 50 m was subject to repair. The auxiliary sleeve was made of a 100 micron thick polyethylene terephthalate film and turned out with compressed air supplied under a pressure of 0.5 ati. The combined sleeve was made of felt, consisting of a mixture of polyester and polyamide fibers, coated with a 400 micron thick layer of thermoplastic film based on a mixture of polyethylene and polypropylene.

 Example 3

 It was carried out analogously to example 1, but a pipe with a diameter of 500 mm and a length of 75 m was subject to repair. An auxiliary sleeve was used from a film of mixed composition / 80% weight. low pressure polyethylene and 20% weight. polypropylene / 150 microns thick. The eversion of this sleeve was carried out with compressed air supplied under a pressure of 0.25 ati. The combined sleeve was used from synthetic felt coated with a layer of thermoplastic polyurethane, 500 microns thick.

 The technical result in the implementation of this invention is expressed in expanding the technological capabilities of the method, namely, the possibility of coating the inner surface of pipes with a length of more than 50 m and a diameter of more than 400 mm. In this case, the analysis of the properties of the coating material obtained during the testing of witness samples cut from the zones of the “tray” part / cm. the table, examples 1-3 /, in comparison with the properties of the coating material of the reproduced sample according to US patent N 4064211 shows the superiority of the composite according to the application for physical and mechanical properties and water absorption. This superiority is ensured by a more uniform than in the prototype, the content of the binder in different areas of the coating, with the exception of the variation in its thickness and, as a result, the stability of the curing system.

Claims (4)

 1. The method of coating the inner surface of the pipeline, which consists in introducing into it a combined sleeve made of a composite based on a fiber-impregnated polymer binder with an outer film coating, fixing the end of the combined sleeve on the pipeline, turning it off and pressing it against the pipeline wall under the influence of liquid pressure and subsequent polymerization, characterized in that before the introduction of the combined sleeve into the pipeline in the last place an auxiliary sleeve of thermoplastic second film and the last administered a combined sleeve.  2. The method according to claim 1, characterized in that the auxiliary sleeve is placed in the pipe by eversion.  3. The method according to PP.1 and 2, characterized in that the eversion of the auxiliary sleeve is carried out by the action of compressed air under a pressure of 0.1 - 0.5 atm.  4. The method according to claims 1 to 3, characterized in that the polymerization of the combined sleeve is carried out in a closed volume formed by an auxiliary sleeve and an outer film coating of the fibrous material.

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