RU2532473C2 - Pipe weld with internal coating - Google Patents

Abstract

FIELD: process engineering.

SUBSTANCE: invention relates to construction of pipeline with internal coating with the help of welding. Weld of pipeline with internal coating comprises jar bush and sealant. Said composite jar bush consists of two bushings. Internal bushing is made of rustproof steel while external bushing is made of carbon or low-alloy steel. Jar bush is secured via external bushing by pipes weld while internal bushing features larger length than external bushing. Internal bushing extending end overlap the pipe internal coating. Sealant is fitted between extending ends of internal bushing ends and pipe ends.

EFFECT: higher reliability of weld and weld zone protection against corrosion.

5 cl, 2 dwg

Description

The invention relates to pipeline transport, and in particular to the connection of pipes with an inner coating using electric arc welding, and can be used in the construction of pipelines for oil, gas, petrochemical, housing and communal services and other industries.

Known invention:

The welded joint of the pipeline (patent RU 2283739, B23K 31/02, F16L 13/02, publ. Bull. 26 from 09/20/2006), containing metal pipes with a protective coating applied to their inner surface and a sleeve placed inside the pipes, where the welded joint is made by manual and / or automatic welding to obtain a weld, the area of which exceeds the area of the normal section of the pipes, and the site has ring elements, ring unreinforced and / or reinforced rubber seals, heat-insulating material, sealing material, G-arr a basic ring stop or at least three L-shaped stops equally spaced in the radial plane, used to set the centers of mass, the sleeve located inside the tubes is made with a cylindrical section and the flared and / or mechanically machined blade tools, conical sections and placed inside the pipes so that the edges of the pipes are in contact with the L-shaped ring stop or L-shaped stops, the protective coating on the inner surface of the pipes is applied at a distance from their ends with formed in the zone of applying the thermally unloaded zone, the L-shaped ring stop or the L-shaped stops are placed on half the length of the sleeve and are rigidly fixed on its outer surface, a protective coating is applied to the inner surface of the cylindrical and conjugated conical sections of the sleeve, the ring elements are rigidly fixed to the outer surface of the cylindrical section of the sleeve, are equally offset from its ends and installed opposite each other, ring unreinforced and / or reinforced rubber seals are placed on the outer overhnosti sleeve between the deposited onto the inner tube surface protective coating, the ends of the annular elements and the conical portions of the sleeve and tightly in contact with them, insulating material fixedly secured to the outer surface of the cylindrical portion of the sleeve between the ends of the ring members, the sealing material is applied to the outer surface of said conical sleeve sections.

This welded joint of the pipeline is very complex and laborious to manufacture, and most importantly, reduces the cross section of the pipeline by a large amount for pipe connections and especially for pipelines of small diameters. The fastening of the assembly in the area of the weld is very weak and on the pipelines through which the media are transported under high pressure, these assemblies are torn off by a stream and assembled in one place. That is, the reliability of the protection of the weld and heat-affected zone in the pipeline is not provided.

The invention is also known:

A pipe joint with an internal anti-corrosion coating (RF Patent No. 2228484, class F16L 58/04, according to application 99108283/0699/06 dated 04/20/1999), containing two pipes with an internal enamel coating and a sleeve installed coaxially inside them to form an annular groove is made on the outer surface of the sleeve, on the outer surface of the sleeve, in the middle section of which radial thrust protrusions are made at the same time as the sleeve body, while annular grooves are made in the end sections of the sleeve, in which the sealing elements are mounted, and the entry cones, waiting for the outer surfaces of which and the inner surface of the pipes there is adhesive material, where annular stepped grooves are made at the end sections of the sleeve, and the sealing elements are made in the form of elastic cuffs of a L-shaped cross section, the visor of which is located at an obtuse angle relative to the vertical strut and faces side of the inner surfaces of the pipes, with the end of the visor facing the joint of the pipes to the mounting seam, and the space between the outer surface of the sleeve, cuffs and inner the surface of the pipe is filled with adhesive material.

The considered design of the connection of pipes with an internal anti-corrosion coating, which is considered as a prototype, is very complex and laborious to manufacture, which also reduces the cross section of the pipeline by a large amount for pipe connections and especially for pipelines of small diameters. The fastening of the sleeve in the area of the weld with the help of the thrust protrusions is very weak and on the pipelines through which the media are transported under high pressure, these nodes also breaks the flow and collects them in one place. That is, the reliability of the protection of the weld and heat-affected zone in the pipeline is not provided.

An object of the invention is to increase the reliability of protection of the weld and heat-affected zone of pipe joints in the pipeline against corrosion, simplify and reduce the cost of the structure by reducing the number of parts, reducing the resistance to fluid flow by increasing the bore at the installation location of the liner.

The technical result is achieved by the fact that in the welded joint of pipes with an inner coating containing a liner and sealant, it is new that the liner is made of composite, consisting of two bushings, the inner sleeve is made of corrosion-resistant steel, and the outer sleeve is made of carbon or a low-alloy steel grade, while the liner is fixed through the outer sleeve to the pipeline by a welded pipe joint, and the inner sleeve has a greater length than the outer sleeve, and the protruding ends of the bushings an inner cover covering the inner tube, and between the protruding ends of the inner sleeve and the ends of the pipes is hermetic. The inner and outer bushings are interconnected by a mechanical connection, and their ends are disconnected by a dielectric material. At the ends of the inner sleeve are made cones in the form of a cone. At the ends of the pipes, sockets were made under the liner. An annular protrusion is made in the middle part of the outer sleeve.

This design of the welded connection of pipes with the inner coating allows to simplify the liner by reducing the number of parts and thereby reduces its cost, and the absence of an inner coating in the liner allows increasing the cross-section in the places where the liner is installed, since there is no need to protect the liner liner opposite pipe weld, that is, the use of heat-shielding materials disappears while leaving a large gap between the liner pipe ends and ends, which reduces resistance to fluid flow by increasing the bore at the installation location of the sleeve. Fastening the liner through the sleeve outer to the pipeline by a welded pipe joint increases the reliability of the protection of the weld and the weld zone of the pipe welds in the pipeline, since the liner cannot be moved by the fluid flow, since it is welded around the perimeter to the pipe weld. The connection of the inner and outer bushes with a mechanical connection allows them to be protected from movement, and the separation of their ends by a dielectric material protects against contact corrosion when liquid enters. The presence of an internal cone-shaped socket at the ends of the sleeve reduces hydraulic losses and allows the passage of scrapers when cleaning the pipeline. The presence of sockets at the ends of the pipes under the sleeve increases the cross-section of the pipeline along the pipe joints. The presence of an outer annular protrusion in the middle part of the sleeve simplifies the installation of the liner at the ends of the pipes to be connected, since the liner does not shift relative to the ends of the pipes.

The invention is illustrated by drawings.

Figure 1 shows the welded joint of pipes with an inner coating, consisting of pipes 1, inner coating 2, liner, consisting of an outer sleeve 3 of carbon or low alloy steel and from an inner sleeve 4 of stainless steel, seal type cuff 5 sealant 6 and weld 7.

Figure 2 shows another embodiment of the welded joint of pipes with an inner coating, where at the ends of the pipes 1 a bell 8 is made.

The assembly of the pipe connection is as follows: on the inner surface of each end of the pipe 1 with the inner coating 2, where a part of the inner coating is removed from the end of the pipe 1 at a safe distance, sealant 6 is applied, as well as on the protruding ends of the sleeve of the inner 4 from corrosion-resistant steel, on which the cuffs are pre-fitted 5. Insert the liner into the pipe 1 until the annular protrusion of the outer sleeve 3 contacts the pipe end 1, and then put the liner end of the second pipe 1. onto the sleeve, and the sealant 6 is full it fills the gap between the protruding ends of the sleeve of the inner 4 and the ends of the pipes 1. And the cuffs 5 center the ends of the sleeve of the liner relative to the inner surface of the ends of the pipes 1 and at the same time displace excess sealant 6 from the ends of the pipes 1. Weld the pipes 1 by electric arc welding to form a weld 7.

Assembling the connection of pipes 1 having sockets 8, is carried out in a similar way.

Using this design of a pipe welded joint with an inner coating, the reliability of protecting the weld and heat-affected zone of pipe joints in the pipeline against corrosion is increased, the structure is simplified and cheapened by reducing the number of parts, and resistance to fluid flow is reduced due to an increase in the flow cross-section at the places where the liner is installed.

References

1. Patent RU 2283739, B23K 31/02, F16L 13/02, publ. Bull. September 26, 2006.

2. RF patent No. 2228484, cl. F16L 58/04, according to the application 99108283/0699/06 of 04/20/1999.

Claims (5)

1. A welded joint of pipes with an inner coating, comprising a liner and a sealant, characterized in that the liner is made of a composite consisting of two bushings, where the inner liner is made of corrosion-resistant steel and the outer liner is made of carbon or low alloy steel, wherein the liner is fixed through the outer sleeve to the pipeline by a welded pipe joint, and the inner sleeve has a greater length than the outer sleeve, and the protruding ends of the inner sleeve overlap the inner ytie tubes, and between the protruding ends of the inner sleeve and the ends of the pipes is hermetic. 2. The compound according to claim 1, characterized in that the inner and outer bushings are interconnected by a mechanical connection, and their ends are disconnected by a dielectric material. 3. The compound according to claim 1, characterized in that at the ends of the inner sleeve are made cones in the form of a cone. 4. The compound according to claim 1, characterized in that at the ends of the pipes are made sockets under the liner sleeve. 5. The compound according to claim 1, characterized in that in the middle part of the outer sleeve an annular protrusion is made.

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