RU2338116C2 - Device for prevention of development of slit-shaped and corrosion defects of pipeline walls - Google Patents

Abstract

FIELD: building, the pipeline.

SUBSTANCE: invention concerns pipeline transport and can be used for maintenance and repair of pipelines for local decrease in hoop tension from internal pressure in places of defects of pipelines (rust, cracks, dents, etc.). Mount the tight socket end supplied with a branch pipe with a through axial aperture on a defective pipe run. The crane which clearing hole is coaxial with a through axial opening of a branch pipe in which the blind flange with possibility of its moving is placed is placed on the branch pipe. The branch pipe is supplied with a bypass; the connecting pipe which channels through passage is connected to a through axial aperture of a branch pipe. The connecting pipe is supplied by the crane connecting a via axial opening of the branch pipe with a pressure metre or atmosphere. The angular thread for a threaded coupling with a blind flange is executed in a via axial opening. The device is supplied by the tool for blind flange screwing up.

EFFECT: expansion of an arsenal of means for repair of pipelines.

3 cl, 2 dwg

Description

The invention relates to pipeline transport and can find application, in particular, in the operation and repair of pipelines, namely for local reduction of ring stresses from internal pressure in the places of pipeline defects (corrosion, cracks, dents, etc.)

The reduction of ring stresses is carried out by mounting or welding a steel full-sleeve coupling on the pipeline.

Closest to the proposed invention is a device for preventing the development of crack-like and corrosion defects of the walls of the pipelines, including a sleeve mounted on a defective section of the pipeline (RF patent No. 2097646, IPC 7 F16L 57/02, BI No. 33, 11/27/97).

A disadvantage of the known device is that the simple installation of the coupling on the defective section of the pipeline does not give a sufficient effect, since this does not reduce the stress state of the wall of the pipeline at the place of the defect and, therefore, does not inhibit its development, especially for crack-like defects.

The objective of the proposed device is a local reduction of annular tensile stresses in the pipe wall at its working pressure to prevent the development of crack-like and corrosion defects of the pipe walls.

The problem is solved due to the fact that in the device for preventing the development of crack-like and corrosion defects of the walls of the pipeline, including the sleeve mounted on the defective section of the pipe, the sleeve is sealed and equipped with a nozzle with a through axial hole and a valve located on the nozzle, the passage opening of which is aligned with the through the axial hole of the nozzle, while in the through axial hole of the nozzle there is a plug with the ability to move, the nozzle is equipped with a bypass and a fitting m, through passages of which are connected with a through axial hole nozzle, wherein the nozzle is provided with a tap connecting an axial through hole nozzle with a pressure gauge or atmosphere. In addition, a screw thread is made in the through axial hole for threaded connection with a plug. In addition, the device is equipped with a tool for screwing the plug.

Figure 1 shows a device with a plug in the position of the feed of the working fluid into the cavity between the pipeline and the coupling.

Figure 2 shows a device with a plug in the position of the blocked axial hole.

A device for preventing the development of crack-like and corrosion defects of the walls of the pipelines is a sleeve 2 mounted on the pipe 1, made tight, with the formation of a cavity 3, which may be annular in cross section. The coupling 2 is equipped with a pipe 4 with a through axial hole 5, in which the plug 6 is placed with the possibility of movement. A screw thread 7 is made in the hole 5 for a threaded connection with a plug 6. On the pipe 4 there is a valve 8 with a through hole 9, which is coaxial to the hole 5. The pipe 4 is equipped with a bypass 10, the passage channel 11 of which is connected to the hole 5 of the pipe 4. The pipe 4 is equipped the fitting 12, the passage channel 13 of which is also connected with the hole 5 of the pipe 4. The fitting 12 is equipped with a valve 14 connecting the hole 5 with the pressure gauge 15 or the atmosphere. The device is equipped with a tool 16 for screwing the plug.

The device operates as follows.

For example, a welded sleeve 2 is mounted on a defective section of the pipeline 1, and it is sealed and annular in cross section with the formation of a cavity 3. The sleeve 2 is equipped with a pipe 4 with a valve 8 installed on it. Through the passage opening 9 of the valve 8 and the bypass passage 11 in 10 cavity 3 serves a working fluid that does not contain oxidizing agents, such as nitrogen, under a pressure not exceeding the working pressure in the pipeline, while the voltage in the wall of the pipeline decreases inversely with the difference in pressure between the working (internal) and supplied o (outdoor). At the same time, the position of the plug 6 does not prevent the working fluid from entering the cavity 3. Then, the nozzle 4 is closed with a valve 8. If necessary, check the tightness of the coupling 2 on the nozzle 4 and install a removable pressure gauge 15, connecting it through the passage channel 13 with the cavity 3. If there is no pressure drop in cavity 3 judge the tightness of the coupling 2. If necessary, reduce the oxygen concentration in the air mixture with the supplied gas in the cavity 3 after checking the tightness of the cavity 3 by the valve 14 through the passage channel 13 of the fitting 12 open the pipe 4 and pressure of gas in the cavity 3 is reduced to atmospheric pressure. Then the valve 14 is closed, the valve 8 is opened and gas is re-fed into the cavity 3 between the pipeline 1 and the sleeve 2. Due to this, the oxygen concentration at the surface of the pipeline is reduced, which helps to reduce and slow down the corrosion processes on the surface of the defective sections of the pipeline. After this, the valve 8 is closed, a tool 16 is installed on it for screwing the plug 6, the valve 8 is opened and the plug 6 is screwed, thereby blocking the axial channel 5 and sealing the cavity 3.

The application of the proposed device can reduce stress in the wall of the pipe, remove oxygen from the damaged surface of the pipeline and thereby prevent the development of crack-like and corrosion defects on the surface of the existing pipeline and thereby ensure trouble-free operation of the pipeline without decommissioning and replacing the defective section. Using the proposed device, it is possible to check the tightness of the mounted (welded) on the pipe coupling.

Claims (3)

1. Device for preventing the development of crack-like and corrosion defects of the walls of pipelines, including a sleeve mounted on a defective section of the pipeline, characterized in that the sleeve is sealed and equipped with a nozzle with a through axial hole and a valve placed on the nozzle, the passage opening of which is aligned with the through axial hole nozzle, while in the axial bore of the nozzle there is a plug with the ability to move, the nozzle is equipped with a bypass and a fitting, the passage channels of which x connected with a through axial hole of the nozzle, and the fitting is equipped with a valve connecting the through axial hole of the nozzle with a pressure gauge or atmosphere. 2. The device according to claim 1, characterized in that in the through axial hole a screw thread is made for threaded connection with a plug. 3. The device according to claim 1, characterized in that it is equipped with a tool for screwing the plug.

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