RU2786612C1 - Trenchless pipeline repair method - Google Patents

Abstract

FIELD: pipeline transport.

SUBSTANCE: invention relates to pipeline transport and can be used when replacing old pipelines without opening the ground, laying or replacing faulty pipes, repairing or connecting pipes on the water surface or under water - in or on a frozen surface. A method for trenchless repair of a pipeline, which includes pulling a head through an old pipe, consisting of a cylindrical body, to the back of which a replacement pipeline is attached, the head is pulled through steel drill rods, in the front part of the cylindrical body, vertical and horizontal stiffeners are crosswise located, the protruding parts of which have bevels from the edge of the front part of the cylindrical body with the formation of a narrowed cross-shaped tip, and in the upper part of the horizontal stiffener there is a hole through which the drill rods are attached.

EFFECT: improving the reliability, efficiency and simplification of the method for trenchless pipeline repair.

1 cl, 2 dwg

Description

The invention relates to pipeline transport and can be used when replacing old pipelines (TP) without opening the ground, laying or replacing faulty pipes, repairing or connecting pipes on the water surface or under water - in or on a frozen surface.

Repairs of pipeline crossings through artificial and natural obstacles are the most costly and technologically complex work in the construction and restoration of linear pipeline systems. The use of trenchless methods of repair of TS and replacement of TS by the method of pulling "pipe in pipe" at the intersections with natural and artificial obstacles makes it possible to reduce material and time costs. In addition, the use of this method without destroying the old TC allows you to provide additional protection for the new TC as a protective case from the old TC. The presence of contaminants in the internal cavity prevents the process of pulling through, increasing the likelihood of jamming of the dragged TS in the repaired one.

Therefore, the improvement of existing and the development of new methods of trenchless repair of pipeline sections is an urgent task.

There are known methods for repairing TS crossings through artificial and natural obstacles by replacing transitions with closed and open methods with the dismantling of the old section and laying the new TS in trenches developed by earthmoving equipment or dragging using the horizontal directional drilling method (STO Gazprom 2-2.1-249-2008).

The disadvantages of such methods are their high cost and long repair time when the gas supply to the consumer is interrupted.

A method of trenchless replacement of TP is known (RF Patent 2719417, publ. 04/17/2020). The method includes technology for preparing a laying of a new TS in a destructible TS, expanding a well for its laying, pushing a new TS into the expanded sections of the well along the route of the destructible TS.

The disadvantages of this method are: a long repair time and the destruction of the old TP, i.e. lack of additional protection in the form of a case from the old TP.

A method is known for trenchless replacement of a large-diameter TP (RF Patent No. 2270952, publ. 27.02.2006), which consists in replacing the old TP with sections with periodic pulling of a new TP into the place of the remote section, for which the old TP is cut from the inside with an annular cut, longitudinal cuts are performed in the area to be removed and dismantled.

The disadvantages of this method are: the need to create large traction forces during the repair of extended sections of the TS, the destruction of the repaired TS, i.e. lack of additional protection in the form of a case from the old TP.

There is a known method for sanitizing TP (RF Patent 2744676, publ. March 15, 2021). This method consists in coating the inner surface of the TC and inserting a sleeve and heat-resistant hoses into the cleaned TC, pressing the sleeve against the wall of the TC with water or air pressure, followed by polymerization of the polymeric binder sleeve with hot water or steam.

The disadvantage of this method is the possible decrease in the operating pressure in the heat exchanger, which will be limited by the values of the strength characteristics of the polymer material covering the inner surface of the old heat exchanger.

A known method of pulling through the pipeline (RF Patent No. 2023935, publ. 30.11.1994), which consists in pushing the TP using support elements and traction. The supporting elements on the surface of the TS are located along a helical line. An axial force is applied to the tail part of the pipe and the TP is given a rotational movement.

The disadvantages of this method are: the impossibility of controlling the speed of rotation of the TC in the process of pulling through, the jamming of the new TC in the process of pulling through in the presence of contamination in the internal cavity of the old TC, which means low reliability and efficiency of the method.

The closest to the claimed technical solution is the invention "Method of trenchless replacement of an underground pipeline" (RF Patent No. 2504708, publ. 20.01.2014), taken by us as a prototype. The method includes pulling through the old pipe by means of a pull cable a head consisting of a conical tip and a cylindrical body. A replacement pipeline is attached to the rear part of the cylindrical body of the head, while rollers are located on the conical tip of the head, the rotation axes of which are perpendicular to the axis of the old pipe. The technical result of the invention is to increase the permeability of the tip, reduce the load on the equipment, increase the length of the repaired section of the pipeline.

The disadvantages of this method are its low efficiency and reliability due to the high probability of jamming of a new TS with a closed head during pulling in the presence of contamination in the internal cavity of the old TS, which requires an increase in traction and additional passes when pulling a new TS inside the old TS when performing repair work or excludes the possibility of performing repairs in this way. Also, when implementing this repair method, additional measures are required to store the traction cable into the cavity of the old TS.

The technical problem solved by the invention is the creation of a reliable, efficient and easy-to-perform method for trenchless pipeline repair.

The technical result from the use of the invention is to increase the reliability, efficiency and simplification of the method of trenchless pipeline repair.

The specified technical result is achieved by the method of trenchless repair of the pipeline, which includes pulling through the old pipe a head consisting of a cylindrical body, to the back of which a replacement pipeline is attached, the head is pulled through steel drill rods, vertical and horizontal ribs are crosswise located in the front of the cylindrical body stiffeners, the protruding parts of which have bevels from the edge of the front part of the cylindrical body with the formation of a narrowed cross-shaped tip, and in the upper part of the horizontal stiffener there is a hole through which drill rods are attached.

The present invention is illustrated below by the following examples and FIGS. In FIG. 1 shows a diagram of the implementation of the method, in Fig. 2 - the proposed design of the open head.

The head of the open structure (1) consists of a hollow cylindrical body (2), in the front part of which are placed, for example, welded, a vertical stiffener (3) with bevels and a horizontal stiffener (4) with bevels and a hole (5) for fastening steel drill rods (6). The head (1) is made of the same material from which the repaired pipe is made, for example, steel. To the back of the head (1) is mounted, for example, using a welded joint, a new replacement TC (7).

The method is carried out as follows.

On FIG. 1 shows a scheme for organizing trenchless repair of TS. The repaired section of the transformer substation is disconnected from the general system. Two pits are developed at the work site: a receiving one (8) and a working one (9) before and after an artificial or natural barrier (10), respectively, for access to the pipe, as well as stocking and receiving a new TP being dragged (7).

A pre-mounted new TS (7), with a length corresponding to the length of the repaired section of the old TS and an outer diameter of 20-40% less than the diameter of the repaired old TS, is laid in the pulling direction. The head (1) is connected to the TP (7), for example, by welding. Using a directional drilling unit (11), steel drill rods (6) are pulled into the cavity of the old TP (12) from the working pit (9) to the receiving pit (8). Rods (6), each with a length of 6 to 10 meters, are interconnected by a threaded cone connection so that their total length is not less than the length of the repaired section. The rods (6) are fixed to the head (1) through the hole (5) using standard mounting connectors. With the use of pipe-laying cranes (13), a directional drilling unit (11), a new TP (7) is pulled. During operation of the directional drilling unit (11), the rods (6) are pulled by the head (1) towards the working pit (9) through the cavity of the old TP (12). After pulling, the head (1) is dismantled and the repaired section is connected to work in the general system.

When passing the bends of the old TS (12), bevels (3, 4) on the vertical and horizontal stiffeners of the head (1) do not rest against the inner wall of the TS (11) at the bends, which reduces the resistance to movement of the open head (1) and, accordingly , new stretched TP (7).

If there are contaminants in the cavity of the old TS (12) (sand, silt or soil) that can cause jamming, they enter the cavity of the new TS (7) through the open front part of the head (1), beveled stiffeners (3, 4) reduce resistance when the pipe moves through contaminated areas in the cavity of the old TP (12).

Example 1

At the section of the underwater crossing of the pipeline with an outer diameter of 530 mm and a length of 1500 meters, it is necessary to carry out repairs by pulling a new replacement pipeline into it, having an outer diameter of 325 mm and a length of at least 1500 meters.

Before starting work, two pits are developed before and after the water barrier for access to the pipe, as well as stocking and receiving a new pipeline. The cavity of the old TP has pollution in the form of sand and silt.

With the help of a directional drilling unit, rods (6) are pulled through the old TP from the working pit (9) to the receiving pit (8). To a pre-assembled new replacement TP with a diameter of 325 mm and a length of 1500 meters, an open structure head with a diameter of 325 mm is welded. The head (1) is connected to the rods (6) using a U-shaped fastening through the hole (5). The directional drilling unit (11) pulls the rods (6) in the direction from the receiving pit (8) to the working pit (9), dragging along a new replacement TP.

Example 2

The protective case at the intersection with the highway, having an outer diameter of 530 mm and a length of 150 meters, has cavity contamination in the form of clay and sand. The new replacement TS has an outer diameter of 325 mm and a length of at least 150 meters. Using a directional drilling unit, rods (6) are pulled through the protective case from the working pit (9) to the receiving pit (8). To a pre-mounted new replacement TP with a diameter of 325 mm and a length of at least 150 meters, an open structure head (1) with a diameter of 325 mm is welded, through the hole (5) the head is attached to the rods (6). The directional drill (11) pulls the rods (6) in the opposite direction, dragging the new pipeline with it.

Industrial applicability.

The head of the open design is made of a material made according to specifications or GOST, corresponding to the material of the new replacement pipeline to ensure the reliability of their connection. The outer diameter of the head of the open structure (1) must be no more than the outer diameter of the new threaded TS.

Thus, the present invention makes it possible to implement a simple-to-execute method of trenchless repair of a pipeline due to the design of the head, which makes it possible to attach steel drill rods to it. The open design of the head with a beveled shape of its stiffening ribs, which allows collecting pollution (sand, soil, silt, etc.) into the cavity of a new substituting TP, reduces resistance and friction during its movement, the load on the directional drilling rig, traction force, and energy costs when performing work, it increases the length of the new replacement TS, making the method of trenchless pipeline repair reliable and efficient.

Claims (1)

A method for trenchless repair of a pipeline, which includes pulling a head through an old pipe, consisting of a cylindrical body, to the back of which a replacement pipeline is attached, characterized in that the head is pulled through steel drill rods, in the front part of the cylindrical body, vertical and horizontal stiffening ribs protruding parts of which have bevels from the edge of the front part of the cylindrical body with the formation of a narrowed cross-shaped tip, and in the upper part of the horizontal stiffening rib there is a hole through which drill rods are attached.

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