RU2429404C1 - Section of under water pipeline and procedure for its fabrication - Google Patents

Abstract

FIELD: machine building.

SUBSTANCE: between pipes coaxially fixed one relative to another by curling there is formed gap. The gap is filled with two cylinder closed casings secured along screw line on external side of an internal pipe. One of casings is filled with compressed air or inert gas, while a flexible rod is inserted into another casings. The external pipe is connected on both sides with a lock of signal elements made in form of pressure tight circular cases with buoys inside them made of synthetic foam and cables connecting buoys with the internal pipe. Length of the cables is equal to depth of pipeline sections installation. The external pipe is curled from one end on the internal one. Two cylinder closed casings are wound on the internal pipe and are pressed into the curled section of the pipe. Further, there is curled another end of the external pipe. Length of casing winding is accepted as equal to width of disturbance (zone of tectonic rupture) B. Value of press-fitting of the casings is determined from ratio B=0.9∗Z∗d, where Z is number of coils of two cylinder closed casings, psc, d is their diameter, m. The pipe of bigger diameter is used for pulling signal elements out in case of internal pipe rupture.

EFFECT: upgraded accuracy of determination of place of pipeline rupture.

Description

The invention relates to pipeline transport, and in particular to structures of the underwater pipeline and methods for its manufacture.

The known construction of the section of the underwater pipeline (Borodavkin P.P. and others. Underwater pipelines. M: Nedra, 1979, pp. 11-14). The design contains an inner pipe installed inside the outer pipe, and end elements connecting the pipes to each other with sealing of the annular space, filled with a ballasting composition. A method of assembling a pipeline from sections of such a design consists in installing an inner pipe with subsequent installation of the end elements and sealing the annulus after connecting the ends of the pipes. The final operation of assembling the section of the pipeline is filling the annular space with ballasting composition through special channels blocked by valves, followed by connecting the finished sections to each other.

The disadvantage of this device is the difficulty of detecting the place of rupture of the pipeline under water and leakage transported until the discovery of the rupture.

A known section of the underwater pipeline and the method of its manufacture, adopted as a prototype in part of the device (RF patent No. 2072466, publ. 01.27.1997). The subsea pipeline section comprises an inner pipe mounted with an eccentric clearance in the outer pipe by means of locking end elements. Ballasting elements are placed on the pipe, and a drainage tube with check valves is placed in the annulus. The tube is permeable to gas and liquid and contributes to their removal from the annular space. The latter can be partially or completely filled with cement or concrete mortar.

The disadvantage of this device is the difficulty of detecting the place of rupture of the pipeline under water and leakage transported until the discovery of the rupture.

The technical result of the invention in terms of the device is the elimination of leaks when a pipeline ruptures until a rupture is detected and simplifies the determination of a rupture of a pipeline.

The technical result in terms of the device is achieved by the fact that in the section of the underwater pipeline, including the inner pipe, installed with a gap inside the outer pipe, according to the invention, the gap between the coaxially fixed rolling pipes relative to each other is filled with two cylindrical closed shells fixed along a helical line on the outside of the inner pipes, one of which is filled with compressed air or inert gas, and a flexible rod is placed in the other, while the outer pipe is connected on both sides lock with signal elements made in the form of sealed annular casings with syntactic foam buoys inside them and cables connecting buoys to the inner pipe, the length of the cables being equal to the installation depth of the pipeline section.

A known method of constructing an underground pipeline at the intersection of tectonic faults (RF patent No. 2256839, publ. 20.07.2005, bull. No. 20). At the intersection of tectonic faults, a trench is torn off, a pipe segment of a diameter larger than that of the pipeline with end walls is laid through it, through which sections of the main pipeline, interconnected by compensators, are passed through an airtight seal. Through the nozzles, a liquid with a density higher than the density of the product in the pipeline is fed into the pipe segment until the pipeline emerges and then the trench is filled up.

The disadvantage of this method is the narrow scope and leakage of the transported product when the pipeline ruptures.

A known method of constructing an underground pipeline at the intersection of tectonic faults (RF patent No. 2264577, publ. 20.11.2005, bull. No. 32). In the areas of tectonic faults, a trench is torn, trays are installed in it, a pipeline is laid in them. As the trays use halves of recycled car tires. Pre-stack the lower part of the tray from one half of the tires, then lay the pipe in them, cover it with the other halves of the tires on top, fasten them together with side surfaces in groups and fill the trench with soil.

The disadvantage of this method is the narrow scope and leakage of the transported product when the pipeline ruptures.

A known method of constructing an underground pipeline at the intersection of tectonic faults (RF patent No. 2365802, publ. 09/27/2009, bull. No. 24). As trays, cylindrical closed shells filled with compressed air are used, fixed along a helical line on the outside of the pipeline along the length of its welded section, connected to each other by nozzles with the ability to pump and control the air pressure in them through the duct, and the diameter of the shell is taken to be 0, 15D, where - D is the external diameter of the pipeline, m, the distance between the turns is taken equal to 0.2D, the angle of inclination of the turns to the horizontal is taken at least 45 °, and the shells are installed on the pipeline in zones normal fault overlapping this zone more than 4 times the length of the pipeline.

The disadvantage of this method is the narrow scope and leakage of the transported product when the pipeline ruptures.

A known section of the underwater pipeline and the method of its manufacture, adopted as a prototype in part of the method (RF patent No. 2072466, publ. 01.27.1997). The method includes installing a pipe of smaller diameter inside a pipe of large diameter with the formation of a gap between the pipes and their subsequent tight connection between each other at the ends. According to the invention, a pipe of a smaller diameter is eccentrically mounted with a pipe of a larger diameter, after which they are sealed to each other.

The disadvantage of this method is the leakage of the transported product when the pipeline ruptures until it is detected.

The technical result of the invention in terms of the method is the elimination of leaks during rupture of the pipeline until it is detected.

The technical result is achieved by the fact that in the method of manufacturing a section of an underwater pipeline, comprising installing a pipe of a smaller diameter inside a pipe of a larger diameter with the formation of a gap between the pipes and their subsequent tight connection between themselves, according to the invention, the outer pipe is rolled from one edge to the inner, then to the inner pipe wrap two cylindrical closed shells, press them into a sealed section of the pipe, and then roll the other edge of the outer pipe, and the length n shell washing take equal to the width of the violation B, the value of the shell press fitting is determined from the ratio B = 0.9 * Z * d, where Z is the number of turns of two cylindrical closed shells, pcs., d is their diameter, m, and a pipe of larger diameter is used for pulling out the signal elements in case of rupture of the inner pipe.

Section of the underwater pipeline and the method of its manufacture are illustrated by drawings. Figure 1 shows a longitudinal section of the section, the rolling step of one edge of the outer pipe, figure 2 shows a longitudinal section of the section, the rolling step of the second edge of the outer pipe, figure 3 shows the step of installing the section under water, figure 4 shows a cross section sections on the signal element, where:

1 - outer pipe (pipe of larger diameter);

2 - inner pipe (pipeline, for example, for pumping gas);

3 - a cylindrical closed shell with a flexible rod, made, for example, from a hose;

4 - a cylindrical closed shell filled with compressed air, made, for example, of a rubber hose;

5 - sealed annular casings of signal elements made of two pivotally connected parts with a lock 9, for example, in the form of a pin;

6 - buoys of syntactic foam, placed inside a sealed annular casing 5;

7 - cables connecting the inner pipe 2 with buoys 6 of syntactic foam, and the length of the cables is equal to the depth of installation of the section under water;

8 - connection of the pipe 1 with the locks of the sealed annular casings 5 of the signal elements, made, for example, in the form of cables;

9 - locks made, for example, in the form of pins connected to the outer pipe 1 by means of a connection 8;

D is the outer diameter of the inner pipe 2;

d is the diameter of the cylindrical shells 3 and 4;

B is the width of the disturbance, for example, the zone of active tectonic fault.

Due to the possibility of vertical and horizontal displacements of rocks in fault zones, for example, over zones of active tectonic faults, a device is needed to prevent product leakage from pipeline ruptures until a rupture point is detected, indicating the exact rupture site. This is possible due to the creation of an airtight shell designed for short-term sealing of pipelines in the event of a rupture until the rupture point is discovered in order to make a decision on the emergency response method.

The subsea pipeline section contains an outer pipe 1 (a larger diameter pipe) mounted coaxially with a gap relative to the inner pipe 2 (pipe, for example, for pumping gas). The gap between them is filled with two cylindrical closed shells fixed along a helical line on the outer side of the inner pipe 2. The cylindrical closed shell 3 with a flexible rod and the cylindrical closed shell 4 are made, for example, of rubber hoses. The diameter of the cylindrical shells 3 and 4 is determined empirically or experimentally on the basis of the most complete filling of the gap between the inner 2 and outer 1 pipes, taking into account the required amount of press-fit. The cylindrical closed shell 4 is filled with air or an inert gas to give it elastic properties. The pressure of air or inert gas is determined based on the pressure of a gas or other product in the inner pipe 2. Inside the cylindrical closed shell 3, a flexible rod is installed to fix it during winding. The external pipe 1 after rolling on both sides is connected to the locks 9 of the signal elements by means of communication 8. The signal elements are designed to inform about the place of rupture of the pipe 2 due to the floatation of buoys 6 from syntactic foam onto the water surface. The signal elements are made in the form of sealed annular casings 5 with the cables 7 inside them and buoys 6 of syntactic foam. The cables 7 are fixed at one end to the inner tube 2, the other to buoys 6 of syntactic foam. Syntactic foams (also called syntactic foams) are composite materials consisting of microcapsules (microspheres) - hollow small balls of glass, ceramic, polymers bonded with various synthetic resins. Syntactic foams are characterized by high strength, low bulk density, excellent water-repellent and heat-shielding properties. These materials are especially successfully used, in particular, in Japan and the USA for the design and construction of deep-sea vessels. High-strength syntactic foam, "working" as a floating material, is a microscopic hollow glass balls with a diameter of 10-250 microns with a wall thickness of 2-3 microns and a density of 0.25-0.35 g / cm ³ bound by epoxy resin. Such a foam is three to four times lighter than water. Due to this, buoys 6 after tearing out the locks 9 almost immediately float to the surface of the water and signal the rupture site. The length of the cable 7 take more than the depth of the pipeline section.

The method is as follows. A pipe 2 of a smaller diameter is installed inside the pipe 1 of a larger diameter on its axis with the formation of a gap between them. Create a tight connection between them in the following sequence. The outer pipe 1 is rolled from one edge on the inner pipe 2 using the equipment intended for this operation. Two cylindrical closed shells 3 and 4 are wound onto the inner tube 2 along a helix. Previously, a flexible rod is placed in the cylindrical closed shell 3. The cylindrical closed shell 4 is filled with compressed air or inert gas, the pressure of compressed air or inert gas is determined, for example, experimentally. The shells 3 and 4 are pressed into a portion of the inner pipe rolled from one edge. The magnitude of the press fit of the shells 3 and 4 is determined from the ratio B = 0.9 * Z * d, where Z is the number of turns of two cylindrical closed shells, d is their diameter, m. Compliance with this ratio will allow using these shells to create a movable tight joint, eliminating leakage of products from pipeline 2 when it breaks to the point of rupture detection and repair of pipeline 2. The length of winding of shells 3 and 4 is taken equal to the width of violation B to cover the possible interval of pipeline rupture 2. Roll the other edge of the outer pipe loss 1. After rolling, the outer pipe 1 is connected by bonds 8 to the inner pipe 2, for example, using clamps. Due to the connections 8, a pipe of a larger diameter 1 is used to drive the signal elements in case of rupture of the inner pipe 2. When the inner pipe 2 ruptures, the outer pipe 1 moves and one of the connections 8 pulls out the lock 9 of the signal element 5. The hermetic annular casing 5 opens and emerges one of buoys 6 of syntactic foam. By fixing the buoy 6 on the cable 7, he clearly fixes on the surface of the water the place of rupture of the pipeline 2.

During installation of the pipeline 2, the width of the violation zone is determined and, in the above sequence, a protected section of the pipeline is created. After laying the finished structure under water, it is included in the work. When the pipeline 2 ruptures, the shells 3 and 4, due to their elasticity, seal the rupture site, and the longitudinal movements of the outer pipe 1 lead to tearing of the lock 9 through the connection 8. The hermetic ring casing 5 opens and releases the buoy 6 from the syntactic foam. Buoy 6 rises to the surface of the water and fixes the exact place of the gap by holding it with a cable 7. Due to the fact that the casings 5 are located on both sides, any longitudinal movement of the pipeline 2 is fixed by the ascent of one of the buoys 6 from the syntactic foam. Inspection ships periodically ply along the route of the submarine pipeline, so prompt detection of the rupture site will allow repairs to be made as soon as possible. Short-term sealing of the rupture site will eliminate leakage from the pipeline.

The use of this section of the underwater pipeline and the method of its manufacture provides the following advantages:

- elimination of leaks during rupture of an underwater pipeline;

- improving the accuracy of determining the place of rupture of the pipeline;

- reducing the complexity of maintenance.

Claims (2)

1. Section of the underwater pipeline, including an inner pipe installed with a gap inside the outer pipe, characterized in that the gap between the coaxially fixed rolling pipes relative to each other is filled with two cylindrical closed shells fixed along a helical line on the outside of the inner pipe, one of which is filled compressed air or inert gas, and a flexible rod is placed in the other, while the outer pipe is connected on both sides to the lock of the signal elements, made in the form of hermetic ring casings with buoys of syntactic foam inside and cables connecting buoys to the inner pipe, the length of the cables being equal to the installation depth of the pipeline section. 2. A method of manufacturing a section of an underwater pipeline, including installing a pipe of a smaller diameter inside a pipe of a larger diameter with the formation of a gap between the pipes and their subsequent hermetic connection between themselves, characterized in that the outer pipe is rolled from one end to the inside, then two cylindrical are wound on the inner pipe closed shells, press them into the sealed section of the pipe, then roll the other edge of the outer pipe, and the length of winding the shells is taken equal to the width Violations B, the value of the press-fit of the shells is determined from the relation B = 0.9 · Z · d, where Z is the number of turns of two cylindrical closed shells, pcs, d is their diameter, m, and a pipe of a larger diameter is used to pull out the signal elements in the case of rupture of the inner pipe.

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