RU2789170C2 - Gasket for sealing the pipeline junction - Google Patents

Abstract

FIELD: sealing technology.

SUBSTANCE: gasket for sealing the pipeline junction laid in a protective tube-case, made of elastic material, mainly rubber, includes two cylindrical sections of different diameters, a junction section connecting them and two end sections. Each end section is made in the form of a flat ring with a bend inside the corresponding adjacent cylindrical section and is integral with the gasket, and the thickness of the end section is less than the thickness of the adjacent cylindrical section. Each end section and part of the adjacent cylindrical section are made with the possibility of simultaneous wrapping on the outer surface of another part of the adjacent cylindrical section to ensure the possibility of applying a self-vulcanizing rubber band of a given width to the seat on the surface of the pipeline and the protective tube-case, respectively, followed by simultaneous unscrewing of the wrapped elements to ensure tight and uniform compression by the end section of the seat on the pipeline and the protective tube-case, respectively, and the end part of the self-vulcanizing rubber band.

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

1 cl, 3 dwg, 1 tbl

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 soils, swamps, in areas with harsh conditions and permafrost.

The gas and oil pipeline, hereinafter (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-case, into which a humid environment and groundwater penetrate.

It is also known technical solution RF patent 2526137 IPC F16L1/028, 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 modern cuff that can provide reliable sealing of the annular space of the pipeline transition from moisture penetration.

The task is achieved by the fact that on the end part of the cylindrical sections of the cuff 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 part of the adjacent cylindrical section is unscrewed, the end sections tightly and evenly crimp 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 humid environment, increasing the reliability of sealing the annular space of the pipeline transition.

The essence of the proposed invention lies in the fact that the cuff for sealing the transition of a pipeline laid in a protective pipe-case, made of an elastic material, mainly rubber, includes two cylindrical sections of different diameters, connecting their transition section and two end sections. Each end section is made in the form of a flat ring with a bend inside the corresponding adjacent cylindrical section and is integral with the cuff, and the thickness of the end section is less than the thickness of the adjacent cylindrical section. Each end section and a part of the adjacent cylindrical section are made with the possibility of simultaneous wrapping onto the outer surface of another part of the adjacent cylindrical section to provide the possibility of applying a self-vulcanizing rubber tape of a given width to the seat on the surface of the pipeline or protective pipe-case, respectively, with subsequent simultaneous unscrewing of the wrapped elements ( the end section and part of the cylindrical section adjacent to it) to ensure a tight uniform compression of the end section of the seat on the pipeline or protective pipe-case and the end part of the self-vulcanizing rubber tape.

The end sections of the cuff, obstruct! 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 collar in working position with the end portions turned away, and View A shows the collar on the pipeline and protective tube-case with the end portions wrapped 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. coupler clamps for fixing the cuff on the pipeline and protective pipe-case;

9. corrugated cuff;

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

11. support - 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 4 (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, the cuff contains 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 the tightness of the cuff.

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 X of the edge of the end section 4 of the cuff on the pipeline 2:

D _mp - 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 pipe-case 3, the cuff 1 is mounted. I carry out the installation! by simultaneously wrapping the end section 4 and a part of the adjacent cylindrical section 5 for the pipeline 2 (see Fig. 1 and view A) with their outer side on top of the other 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 part of the adjacent cylindrical section 5 of the cuff are simultaneously wrapped and mounted on a protective tube-case. Then, a self-vulcanizing rubber band 6 of a given width is placed on the seat under the cuff on the pipeline 2. In a similar way, a self-vulcanizing rubber band is laid on the seat under the cuff on the protective tube-case 3.

After that, also simultaneously, the end section 4 and a part of the adjacent cylindrical section 5 are unscrewed, 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 design of the cuff made it possible to solve one of the important tasks - to stop the penetration of a moist environment through the end leaks of the self-vulcanizing rubber tape 6, 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 of the non-molded rubber cuff 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 throughout the entire service life of the transition, more than 30 years.

Claims (1)

Cuff for sealing the transition of a pipeline laid in a protective pipe-case, made of an elastic material, mainly rubber, including two cylindrical sections of different diameters and a transition section connecting them, characterized in that it contains two end sections, each of which is made in the form of a flat ring with a bend inside the corresponding adjacent cylindrical section and is integral with the cuff, and the thickness of the end section is less than the thickness of the adjacent cylindrical section, while each end section and part of the adjacent cylindrical section are made with the possibility of simultaneously wrapping onto the outer surface of the other part of the adjacent cylindrical section to ensure the possibility of applying a self-vulcanizing rubber tape of a given width to the seat on the surface of the pipeline and the protective pipe-case, respectively, with subsequent simultaneous unscrewing of a part of the cylindrical section and conc the left section to ensure a tight and uniform compression of the end section of the seat on the pipeline and the protective tube-case, as well as on the end part of the self-vulcanizing rubber tape.

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