RU2789171C2 - Method for mounting the gasket for sealing the pipeline junction - Google Patents

Abstract

FIELD: sealing technology.

SUBSTANCE: invention can be used to seal the inter-tube space of gas and oil pipeline junctions laid in a protective tube-case. Sealing is provided by mounting a gasket made of elastic material, mainly rubber, including two cylindrical sections of different diameters and a transitional section connecting them. The gasket contains two end sections, each of which, before installation, has the shape of a flat ring with a bend inside the corresponding adjacent cylindrical section. Before mounting the gasket, each end section and part of the adjacent cylindrical section are wrapped with the outer side on another part of the adjacent cylindrical section. During installation, the gasket is moved through the pipeline and put on cylindrical sections on the pipeline and the protective tube-case, respectively. A self-vulcanizing rubber band of a given width is applied to the seats under the cylindrical sections on the pipeline and the protective tube-case. Then, the parts of the cylindrical sections and the end sections are folded back on top of the self-vulcanizing rubber band, they are straightened for tight and uniform compression of the self-vulcanizing rubber bands across the entire width on the pipeline and the protective tube-case, as well as for compression by each end section of the seat on the pipeline or protective tube-case, and the end part of the self-vulcanizing rubber band. Then, on top of the cylindrical sections, clamps-ties are installed and crimped.

EFFECT: invention makes it possible to increase the tightness of the inter-tube space of the transition and to provide the possibility of using a self-vulcanizing rubber band with different vulcanization periods.

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Description

The invention relates to the oil and gas industry and can be used for sealing the annulus of gas and oil pipelines with a diameter of 57 - 2250 mm, laid in a protective pipe-case with a diameter of 114 - 2550 mm, under roads, engineering structures, water barriers, in wet pounds, swamps, in areas with harsh conditions and permafrost.

The gas and oil pipeline in the future (pipeline), during the construction of the transition, is dragged on the support-guide rings in a protective pipe-case. The annular space of the transition between the protective pipe-case and the pipeline, upon completion of installation, is sealed on both sides with rubber cuffs (hereinafter referred to as the cuff), and fixed with clamps on the pipeline and the protective pipe-case of the transition. Due to the imperfect design of cuffs and clamps, groundwater penetrates into the annulus of the transition, between the pipeline and the cylindrical part of the cuff, resulting in corrosion that destroys the insulation, support rings, pipeline, control devices and reduces the life of the pipeline, especially in areas with harsh conditions, permafrost and swampy terrain.

Known technical solution, a clamp for fastening the cuff, RF patent No. 2229652 IPC C 17 F16L 33/08, 33/02. The essence of the invention lies in the fact that the clamp is made of one-section, two-section or three-section, depending on the diameter of the pipes, each section is made of a crimp element and two stops, which are made of metal corners. One of the stops is welded on the crimp element, at a distance of 50-300 mm from its end, and the second stop is welded flush to the other end of the crimp element and parallel to it, along the entire length of the stop.

A limiter made of the same material as the crimping element is welded on the lower side of the stop, while the ends of the crimping element and the limiter, on the side of the clamp tightening, are cut off at an angle of 30-45 °, and the distance between them is chosen to be sufficient for free passage in it. end of the crimp element.

The disadvantage of this technical solution lies in the fact that it is difficult to seal the end parts of the cuff with clamps on the pipeline and the protective pipe-case, in the places of bolted connections of the stops of the segments with each other. When tightening the bolted connection of the stops, which are made of metal angles 40 × 40 × 4 mm, the end flat lower part of the angle rises due to the pressure of the crimping element, and a free space opens between the cuff with a wall thickness of S-8-10 mm, the pipeline and the protective pipe - a case into which the humid environment and ground waters get.

It is also known technical solution RF patent 2526137 IPC F16L 1/028, F16L 7/00, which is taken as a prototype, where the clamp device is made similar to RF patent No. 2229652. The cuff is made with a corrugation, a self-vulcanizing rubber tape is applied under the seats of the cuff for reliable sealing of the annular space of the transition. But this drawback has not been completely eliminated, because. Self-vulcanizing rubber band requires a dry environment when vulcanizing. Therefore, a self-vulcanizing rubber band must be kept dry, without a moist environment, until it is completely vulcanized. Or use a rubber band with a minimum self-vulcanization period, which is also a significant drawback of the cuff.

The objective of the proposed invention is to eliminate these shortcomings and to develop a method for mounting a cuff for sealing the pipeline transition, which makes it possible to ensure reliable sealing of the annular space of the pipeline transition from moisture penetration.

The claimed method can be used in the construction of new pipeline crossings, as well as in the repair of existing pipeline crossings.

The task is achieved by using a cuff for mounting, on the end part of the cylindrical sections of which there are end sections with an inward bend, having in a free state the shape of a flat ring and constituting a single whole with the cuff. The end sections of the cuff are made 30-100 mm wide and are mounted without fastening on the pipeline and protective pipe-case. Each end section and a part of the adjacent cylindrical section are made with the possibility of simultaneous wrapping during installation of the cuff on the outer surface of the other part of this adjacent cylindrical section. Said screwing opens on the pipeline or the protective tube-case, respectively, a seat for laying a self-vulcanizing rubber tape of a predetermined width. After laying the self-vulcanizing rubber tape on the seats, each end section and a part of the adjacent cylindrical section are unscrewed over the self-vulcanizing rubber tape, straightened for dense and uniform compression of the self-vulcanizing rubber tapes over the entire width on the pipeline and the protective pipe-case. At the same time, the end sections tightly and evenly compress the seats on the pipeline and the protective pipe-case, as well as in the end part of the self-vulcanizing rubber tape, ensuring complete vulcanization in a dry form, without a wet environment, increasing the reliability of sealing the annular space of the pipeline transition.

The essence of the invention lies in the fact that the sealing of the transition of the pipeline, laid in a protective pipe-case, is ensured by mounting a cuff made of an elastic material, mainly rubber. The cuff includes two cylindrical sections of different diameters, a transitional section connecting them, as well as two end sections, each of which before installation has the form of a flat ring with a bend inside the corresponding adjacent cylindrical section. Before mounting the cuff, each end section and a part of the adjacent cylindrical section are wrapped with the outer side onto the other part of the adjacent cylindrical section. During installation, the cuff is moved along the pipeline and put on cylindrical sections on the pipeline and the protective pipe-case, respectively - a cylindrical section of a larger diameter on the protective pipe-case. A self-vulcanizing rubber tape of a given width is applied to the seats for cylindrical sections on the pipeline and the protective pipe-case. Then the parts of the cylindrical sections and the end sections are unscrewed over the self-vulcanizing rubber tape, they are straightened for dense and uniform compression of the self-vulcanizing rubber tapes over the entire width on the pipeline and the protective pipe-case, as well as for compression by each end section of the seat on the pipeline or protective pipe-case , and the end part of the self-vulcanizing rubber band. Then, clamps-ties are installed and crimped over the cylindrical sections.

After mounting the cuff, its end sections prevent the penetration of moisture to the self-vulcanizing rubber band, due to the compression force, which is calculated during manufacture for various cuff diameters.

The essence of the invention is illustrated by drawings, where:

in fig. 1 shows the sleeve in working position with the end sections turned away, and view A shows the collar on the pipeline and the protective tube-case with the end sections wrapped up before installation;

in fig. 2 shows a cuff in axonometric view, with end sections made in the form of a flat ring with a bend inside the cylindrical sections;

in fig. 3 shows the scheme for calculating the tensile stress of the end cylindrical sections of the cuff in a free position.

The elements shown in the drawings are indicated by the following positions:

1 - cuff for sealing the annular space of the transition;

2 - pipeline;

3 - protective tube-case;

4 - end sections of the cuff;

5 - cylindrical sections of the cuff;

6 - self-vulcanizing rubber band;

7, 8 - screed clamps for fixing the cuff on the pipeline and protective pipe-case;

9 - cuff corrugation;

10 - transition section, including a corrugation and a vertically flat part of the cuff, connecting two cylindrical sections of different diameters;

11 - support and guide rings.

Cuff 1 (Fig. 1, 2, 3) is made of an elastic material, such as rubber, is designed to seal the annular space of the transition of the pipeline 2, laid in a protective pipe-case 3 under roads, railways, engineering structures, water barriers, in wet soils , swamps, in areas with harsh conditions and permafrost. The cuff contains end sections 4, made in the free state in the form of a flat ring (Fig. 1, 2), with a bend in the inner cylindrical sections 5, and constituting a single unit with the cuff.

The end sections of the cuff 4 are made with a wall thickness less than the cylindrical sections 5 with the possibility of simultaneous wrapping of the end sections 4 and part of the adjacent cylindrical sections (see view A in Fig. 1) when mounted on the outer surface of the other part of the adjacent cylindrical sections 5. Wrapping of the mentioned sections is necessary for laying on the seats on the surface of the pipeline 2 and the protective pipe-case 3 self-vulcanizing rubber tape 6 of a given width.

Unscrewing the wrapped elements (end sections 4 and part of cylindrical sections 5 adjacent to them) during installation ensures that the end sections 4 compress the seats on the surface of the pipeline 2 and the protective pipe-case 3, as well as the end part of the self-vulcanizing rubber tape 6, due to the implementation of the end sections 4 in the form of a flat ring in the free state of the cuff.

Cylindrical sections of the cuff during operation perceive loads, both in tension and in compression. And, despite the fact that the cuff is fixed with clamps with ties on the pipeline and the protective pipe-case, in the design of the cuff, which does not have end parts, the moist environment penetrates into the annular space of the transition at the bolted joints of the clamps and between the pipeline, the protective pipe-case and the cuff when moving the pipeline in the axial direction during the operation of the transition.

According to the proposed invention, a cuff is used for installation with end sections having in a free state the shape of a flat ring with a given diameter, which, after installation, provide the necessary compression forces for the pipeline and the protective pipe-case in front of the cylindrical sections and throughout the end sections of the cuff, thereby achieving tightness cuffs.

The calculated values of the tensile stress of the end section can be determined, for example, as follows (see Fig. 3).

Let us determine the amount of stretching λ of the edge of the end section 4 of the cuff on the pipeline 2:

- наружный диаметр трубы (трубопровода 2);

- outer diameter of the pipe (pipeline 2);

D _o - inner diameter of the end part 4 in the form of a flat ring.

The degree of stretching will be:

ε=1-λ

Modulus of elasticity E of the cuff rubber at hardness H=55-60 arb. units Shore A is ~2.5 MPa.

Then the tensile stress at the edge of the end section when mounting the cuff on the pipe will be:

Similarly, calculations are made for the end section 4 of the cuff on the protective tube-case.

An example of calculation is shown in the table:

Thus, with a pipeline diameter of 1420 mm, the tensile stress at the edge of the end section 4 will be 1.6 ... 3.75 kg / cm ² , and with a casing pipe diameter of 1720 mm, the tensile stress at the edge of the end section will be 1.3 ... 3.03 kg / cm ² .

Installation of the cuff on the pipeline and the protective pipe-case is carried out as follows.

After the pipeline 2 is pulled through on the support-guide rings into the protective tube-case 3, the cuff 1 is mounted. Installation is carried out by simultaneously screwing the end section 4 and part of the adjacent cylindrical section 5 for the pipeline 2 (see Fig. 1 and view. A) their outer side from above to another part of the adjacent cylindrical section 5 of the cuff, for free movement of the end section 4 of the cuff through the pipeline 2 to the protective pipe-case 3, because the end section 4 is made with a diameter smaller than the diameter of the adjacent cylindrical section 5 and when the cuff 1 moves along the pipeline 2 to the protective pipe-case 3, it prevents the cuff from advancing. Similarly, the end section 4 and a part of the adjacent cylindrical section 5 of the cuff for the protective tube-case are simultaneously wrapped. Then, a self-vulcanizing rubber band 6 of a given width is placed on the seat under the cuff on the pipeline 2. Similarly, when installing the cuff on the protective tube-case, a self-vulcanizing rubber band is placed on the seat under the cuff.

Then, also simultaneously, the end section 4 and part of the cylindrical section 5 adjacent to it are unscrewed over the self-vulcanizing rubber band 6, straightened to their full length by stretching and lowered onto the pipeline 2 to compress it. The end section and part of the cylindrical section adjacent to it on the protective tube-case 3 are unscrewed in the same way. The sealing of the cuff is carried out due to the tight compression of the end sections 4 of the pipeline 2 and the protective pipe-case 3, respectively, as well as the end part of each self-vulcanizing rubber band. This method of mounting the cuff made it possible to solve one of the important problems - to stop the penetration of a moist environment through the end leaks of the self-vulcanizing rubber tape 6, as well as through the end leaks of the cylindrical sections 5 and in the places of bolted joints of the clamps of the couplers 7, 8, for attaching the rubber cuff to the pipeline and protective pipe-case.

The tests carried out showed a number of advantages of the invention: reliable sealing of the annular space of the transition, low cost of the proposed solution. Insignificant time costs when mounting the cuff on the pipeline and protective pipe-case. Possibility of using self-vulcanizing rubber tape with different curing times, up to three years, because the end cylindrical sections of the cuff will retain their tensile stresses for a long time to ensure the tightness of the cuff.

After one year from the date of installation of the rubber cuffs, the self-vulcanizing rubber tape, under the pressure of the clamps of the couplers for fastening the rubber cuffs, is vulcanized to the pipeline, the protective pipe-case and retains the ability to seal the annular space during the entire service life of the transition, more than 30 years.

Claims (1)

A method for mounting a cuff for sealing the transition of a pipeline laid in a protective pipe-case, characterized in that the cuff, made of an elastic material, mainly rubber, including two cylindrical sections of different diameters and a transitional section connecting them, is put on the pipeline and the protective pipe in cylindrical sections - case, respectively, a self-vulcanizing rubber band of a given width is applied to the seats under the cylindrical sections, clamps-ties are installed and crimped over the cylindrical sections, characterized in that the cuff contains two end sections, each of which before installation has the shape of a flat ring with a bend inside the corresponding adjacent cylindrical section, before installing the cuff, each end section and part of the adjacent cylindrical section are wrapped with the outer side onto another part of the adjacent cylindrical section, then the cuff is moved along the pipeline and the cylindrical section b of a larger diameter are put on a protective tube-case, a self-vulcanizing rubber tape of a given width is applied to the seats on the pipeline and the protective tube-case, after which parts of the cylindrical sections and end sections are unscrewed over the self-vulcanizing rubber tape, straightened them for dense and uniform compression of self-vulcanizing rubber tapes over the entire width on the pipeline, protective pipe-case for compression by each end section of the seat on the pipeline and protective pipe-case, as well as on the end part of the self-vulcanizing rubber tape.

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