RU2637786C1 - Method for protecting interior area of pipe connections with internal coating (options) - Google Patents

Abstract

FIELD: construction.

SUBSTANCE: method includes installing an inner protection sleeve at the junction of the ends of a pipeline. At the end of one of the pipelines, into which the sleeve is inserted for its entire length, longitudinal through-slots are made. The sleeve is equipped with lateral protrusions inserted into the longitudinal slots. After the pipe ends are joined, the sleeve is inserted into the end of the opposite pipeline by means of the protrusions by axial movement to seal the joint of the pipelines and the slots. The pipeline joint is made and the side slots are sealed fixing the protection sleeve. Another method for protecting the interior area of joints of pipelines with an internal coating is also described.

EFFECT: invention makes it possible to expand the field of application of inner protection sleeves by eliminating the need for axial shift of the connected ends of the pipeline and to increase the reliability of protection by eliminating the shift of inner protection sleeves during operation.

2 cl, 7 dwg

Description

The invention relates to the field of pipeline transport and can be used in the construction and repair of pipelines for various purposes, transporting aggressive environments.

A known method of corrosion protection of the weld zone of metal pipes with an internal anticorrosive coating (patent RU No. 2342588, IPC F16L 13/02, published in Bull. No. 36 dated 12/27/2008), including installing a sleeve inside the pipe end having the outer surface of the sealing ring, fixing the sleeve and preparing the ends of the sleeve and pipe for butt welding. The sleeve is made in the form of two telescopically interconnected nozzles, the inner of which is made of corrosion-resistant metal and with an annular protrusion. A sealing ring is placed between the annular protrusion and the inner end of the outer pipe. An external pipe is introduced into the pipe and attached to the pipe. By forcefully moving the inner pipe in the axial direction, the sealing ring is pressed against the annular protrusion and the end of the outer pipe. Then attach the inner pipe to the outer pipe.

The disadvantage of this method is the high cost of the sleeve, since its inner pipe is made of expensive corrosion-resistant steel. Another disadvantage of this method is the large amount of welding when connecting the prepared ends of the pipes, since there are three layers of metal to be welded - the pipe, the outer and inner pipes. A large welding volume causes an increased temperature effect on the inner coating and on the sealing ring. As a result, there is a need to increase the distance from the weld to the ring, which, in turn, increases the total length and cost of the sleeve. In addition, the root of the seam must be performed by a special expensive electrode for welding corrosion-resistant steel, which leads to a higher cost of welding and requires high qualification of the welder.

A known method of connecting pipes with an inner coating (patent RU No. 2226637, IPC F16L 13/02, publ. 04/10/2004), including calibration and expansion of the inner diameter of the ends of the pipes before coating. When connecting pipes into the cavity of their ends, an internal protective sleeve is placed, after which the pipes are welded. The sleeve has an anticorrosive coating, and at the ends there are external sealing elements, which are located in zones of change in the inner diameter of the pipe ends.

The disadvantage of this method is that to place the inner protective sleeve into the cavity of the ends of the pipes to be connected, it is necessary to carry out their axial displacement for joining. This displacement is possible during the construction of the pipeline, when it can be carried out by a pipe welded to the already mounted section of the pipeline. The need for axial displacement causes difficulties in the process of installing the pipe in an existing pipeline to repair the emergency section. In this case, the axial displacement of the connected ends of the pipeline or pipe is impossible. The need for axial displacement of the ends of the pipeline may arise during the construction of the pipeline when performing overlap. This situation occurs when two sections of the pipeline are built from opposite sides towards each other. Axial displacement of the ends of the constructed sections for installation in the connection of the protective sleeve is impossible. Another disadvantage of this method is the unreliable fixation of the protective sleeves in the cavity of the pipeline in the axial direction. During the operation of the pipeline, it becomes necessary to conduct internal cleaning or diagnostic tests with in-tube shells, during the passage of which there is a danger of the protective sleeves breaking in the axial direction.

The technical objectives of the invention are to expand the scope of corrosion protection of pipe connections by internal protective sleeves during construction and repair without axial displacement of its connected ends, ensuring reliable fixation of internal protective sleeves in the pipeline cavity.

The problem is solved by the method, including placement at the junction with the overlap of the end sections of the coating of the inner protective sleeve, made in the corrosion-resistant version and having sealing elements on the outer surface at the ends, and the pipe joint butt.

New is the fact that at the end of one of the pipes into which the inner protective sleeve is inserted the entire length, longitudinal through slots are made, and the protective sleeve is equipped with lateral protrusions inserted into the longitudinal slots, after the ends of the pipes are joined together, the inner protective sleeve is axially protruded by means of lateral protrusions by moving, it is partially inserted into the end of the opposite pipe with sealing from the inside of the pipe joint and through slots, after which the pipes are connected and the side slots are sealed with the internal protective w LCI against axial displacement.

The problem is also solved by a method, including placement at the junction with the overlap of the end sections of the coating of the inner protective sleeve, made in the corrosion-resistant version and having sealing elements on the outer surface at the ends, and connecting the pipes.

What is new is that the distance between the ends of the pipes to be joined is equal to the length of the pipe with an inner coating and a diameter that allows it to be connected end-to-end, with through-cuts being made at the ends of the pipe, and inner protective sleeves with lateral protrusions inserted from both ends placed in the corresponding through-cuts of the nozzle, after the ends of the pipes are joined with the ends of the nozzle, the internal protective bushes are partially introduced into the ends by axial displacement by connecting them pipes with internal sealing of the corresponding joints and through slots, after which the joints are connected and the side slots are sealed with the internal protective sleeves fixed against axial displacement.

In FIG. 1 shows the connected ends of the pipeline.

In FIG. 2 shows the process of connecting the ends of the pipeline to the pipe.

In FIG. 3 shows an external view A of a longitudinal slot with a lateral protrusion mounted therein, an internal protective sleeve.

In FIG. 4 shows the installation process of the inner protective sleeve of the pipe in the cavity of the connected ends of the pipes.

In FIG. 5 shows a pipe that is completely connected to the ends of the pipeline with the installation of internal protective sleeves.

In FIG. 6 shows the connected ends of the pipeline with an excess length.

In FIG. 7 shows the connected ends of the pipeline with the installation of an internal protective sleeve after removing the excess length.

A method of protecting the inner zone of welded joints of pipes with an inner coating can be carried out as follows.

For clarity, we consider the case when it is necessary to connect the ends of the pipeline 1 (Fig. 1) with the missing length for this connection or with a cut out emergency section. The pipeline has an inner coating 2. To connect the ends of the pipeline 1 (Fig. 2) with the inner coating 2, a pipe 3 with an inner coating 4 is installed, in the end cavities of which the inner protective sleeves are pre-installed 5. The inner protective sleeves 5 are made in an anti-corrosion version, for example Corrosion-resistant materials or from steel with anti-corrosion coatings. In the manufacture of the inner protective sleeve 5 is provided with lateral protrusions 6, and at their ends are installed the outer sealing elements 7 and 8 of an elastic material (for example, rubber, polyurethane, rubber, etc.). On the side surface of the ends of the pipe 3, longitudinal slots 9 are made. The inner protective sleeves 5 are installed in the end cavities of the pipe 3 over their entire length so that they do not interfere with the installation of the pipe 3 between the connected ends of the pipe 1. The lateral protrusions 6 of the internal protective sleeves 5 placed in the longitudinal slots 9 of the pipe 3 (Fig. 2 and 3). The side slots 9 can be open from the ends of the nozzle 3, then the side tabs 6 are installed in the longitudinal slots 9 directly from the ends of the nozzle 3 together with the internal protective bushings 5. The side slots 9 can be closed from the ends of the nozzle 3. In this case, first in the end cavities pipe 3 install the inner protective sleeve 5, then through the longitudinal slots enter the side tabs 6, followed by fastening to the internal protective sleeve (thread, welding, glue, etc.). The outer sealing elements 7 (Fig. 2) of the inner protective sleeves 5 located in the cavity of the nozzle 3 are made in such a way that they seal the cavity between the nozzle 3 and the inner protective sleeves 5 with the possibility of longitudinal movement, for example, by the method described in patent RU No. 2557827, in patent RU No. 2342588, etc. (the authors do not claim to be a method of sealing the cavity). After installing the pipe 3 assembly between the connected ends of the pipe 1 carry out its fixing welding tacks. After that, the internal protective sleeves 5 (Fig. 4) are partially inserted into the internal cavities of the connected ends of the pipeline 1 due to longitudinal displacement by means of side protrusions 6 manually or by means of spacers installed between oppositely located side protrusions 6 (not shown conventionally in Fig. 4 ) The ends of the spacers can be moved apart by a mechanism operating on the principle of a screw or hydraulic jack. In the process of longitudinal displacement of the inner protective sleeves 5, the cavity is sealed between them and the ends of the pipe 1 by known methods, for example, the method described in RU patent No. 2080510, in RU patent No. 2226637, etc. (the authors do not claim a method of sealing the cavity). After partial insertion of the inner protective sleeves 5 (Fig. 5) and sealing of the cavity between them and the connected ends of the pipe 1, annular welds 10 of the pipe 3 are made. Then, the longitudinal slots 9 of the pipe 3 are sealed, for example, by welding 11, soldering, glue, etc. . In this case, the side protrusions 6 of the inner protective sleeves 5 are fastened in the sealing layer of the longitudinal slots 9 (they are welded, brazed, glued, etc.), and the excess length of the side protrusions 6 is cut off on the outer surface of the nozzle 3. FIG. 2, 3, 4, and 5, for illustrative purposes, a method of protecting the inner zone of two welded joints of the pipes to be connected using a pipe 3 is shown. Another method is applied without a pipe 3 when removing the extra length L (Fig. 6) of one of the connected ends of the pipe 1 — an overlap formed in the opposite construction of its two sections 12 and 13. In this case, the longitudinal slots 9 (Fig. 7) are made on the side surface of one of the connected ends of the pipeline 1 after removing the extra length L (Fig. 6), where one internal protective sleeve 5 is installed ( Fig. 7). The remaining operations are performed according to the described method with the execution of one annular weld seam 14 connecting the ends of the pipeline 1 sections 12 and 13.

The proposed methods allow:

- to fix the lateral protrusions 6 of the inner protective sleeves 5 in the sealing layer of the longitudinal slots 9, which ensures reliable fixation of the inner protective sleeves 5 from axial displacement under the influence of the pumped medium, treatment devices and diagnostic shells when they are passed through the inner cavity of the pipeline;

- to carry out axial displacement of the inner protective sleeves 5 without axial displacement of the connected ends of the pipeline 1, which allows to expand the scope of application of the methods in the construction and repair of pipelines with internal coating.

The proposed methods for protecting the inner zone of pipe joints with an inner coating allow expanding the scope of application of the inner protective sleeves by eliminating the need for axial shift of the connected pipe ends and increasing the reliability of protection by eliminating the shift of the inner protective sleeves during operation.

Claims (2)

1. A method of protecting the inner zone of pipe joints with an inner coating, comprising placing at the connection point with overlapping end portions of the coating an internal protective sleeve made in an anti-corrosion version and having sealing elements on the outer surface at the ends, and the pipe joint end-to-end, characterized in that the end of one of the pipes into which the inner protective sleeve is inserted the entire length, longitudinal through slots are made, and the protective sleeve is equipped with lateral protrusions inserted into the longitudinal cramps after joining pipe ends inside the protective sleeve by means of axial movement of the lateral protrusions partially introduced into the opposite end of the tube with a sealing inside the pipe joint and the through slits, whereupon pipe connection and sealing lateral slits latching inner protective sleeve against axial displacement. 2. A method of protecting the inner zone of pipe joints with an inner coating, comprising placing at the connection point with overlapping end portions of the coating an internal protective sleeve made in an anti-corrosion version and having sealing elements on the outer surface at the ends, and a pipe connection, characterized in that the distance between the connected ends of the pipes are equal to the length of the pipe with an inner coating and a diameter that allows it to be connected to the ends of the pipes end-to-end, and at the ends of the pipe slots, and from both ends insert the inner protective sleeves to the full length with lateral protrusions placed in the corresponding through-cuts of the nozzle, after the ends of the pipes are joined with the ends of the nozzle, the inner protective sleeves, by means of lateral protrusions, are partially inserted into the ends of the connected pipes with sealing from the inside of the corresponding joints and through slots, after which the joints are connected and the side slots are sealed with the internal protective bushings being fixed from axial displacement.

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