RU2268438C2 - Mode of elimination of gas escape through flange connections without stopping transmission of gas along the gas pipeline - Google Patents

Abstract

FIELD: the invention refers to pipeline transport and is used at repairing of gas-main pipelines of high pressure without stopping the gas transmission.

SUBSTANCE: a technological opening is fulfilled in the lower part of the exterior side of the flange till its inter flange rug, an additional stop-cock is fixed in it, it is closed and a an extruder preliminary filled with self-vulcanizing sealing material is attached to it. In the upper part of the flange one more technological opening in which the second additional stop-clock is fixed. Then the both stop-cocks are opened and a ring insertion is introduced into the inter flange space from the exterior side of the flange and a sleeve tube is put on across the axle of the pipeline. Through an additional stop-cock installed in the lower part of the flange a self-vulcanizing sealing material is introduced into the inter flange connection. After appearance of the sealing material at the output of the second additional stop-cork it is closed and the pressure of the introduced self-vulcanizing sealing material which exceeds the gas pressure in the gas pipeline is created. After appearance of the self-vulcanization sealing material at the output of the second additional stop-cork it is taken away, the opening is closed.

EFFECT: increases containment of flange connections.

1 cl, 3 dwg

Description

The invention relates to techniques for repairing flange joints of gas pipelines, mainly high-pressure gas pipelines.

For normal operation of electrochemical protection systems, certain sections of gas pipelines must be galvanically isolated from each other. Docking of these sections with each other is carried out using insulating flange joints, tightened with studs with insulating gaskets. In addition, flange connections are used on cranes.

During operation of gas pipelines, flange connections are under constant mechanical load due to subsidence of the soil and are exposed to temperature effects due to uneven heating of the upper and lower parts of the valve. Additional mechanical impacts on the joints occur during periodic routine in-line diagnostics or pipeline cleaning using pistons or smart shells.

In this regard, accelerated aging of the interflange sealing rings occurs, their deformation and cracking, which, in turn, leads to gas leaks.

Over time, in the places of gas leaks through the flange connection, due to the throttle effect, numerous shells appear, due to which gas emissions increase. An additional tightening of the flange nuts gives, as a rule, a short-term effect.

There is a method of eliminating gas leaks through flange connections of gas pipeline valves (see. Shut-off valves with ball valves manufactured by the TYAZHPROMARMATURA plant (USSR) Du50-500 mm. - Gorky: MGP USSR, 1977), which consists in the following. The tap, on which there are gas leaks, is cut out, the flange connection is undocked, the surfaces are polished and the sealing ring changes. Then the crane is assembled and installed in its place. The method is time consuming. In addition, when using this method, it is necessary to stop pumping gas through the pipeline, which in some cases is unacceptable.

There is a method of eliminating gas leaks through flange connections of pipelines, (see the declaration patent of Ukraine by application No. 99020739 of 02/09/1999). The method is as follows. Under the flange nuts, gaskets made of durable polymer are installed in series. When tightening the nuts, the polymer is deformed and prevents the gas from escaping through the hairpin cup. The method can be used on a working pipeline without stopping the pumping of gas, however, it has disadvantages. Firstly, leaks along the flange are not eliminated, and secondly, due to a certain fluidity of the polymer, the wafer gap increases over time, which leads to an increase in gas emission.

There is a method of eliminating gas leaks through flange connections of gas pipeline valves while pumping gas through a gas pipeline (see Russian patent for invention No. 2208196 dated July 10, 2003, bull. No. 19), which is a prototype of the claimed invention. The method is reduced to filling the wafer gap with a self-vulcanizing sealant introduced through an additional valve under a pressure exceeding the gas pressure in the gas pipeline. To do this, first make a blind technological hole in the flange, in which an additional valve, for example, a ball type, is fixed. After that, the additional tap is opened and through it the technological hole is extended to the interflange space or the hairpin glass. Further, to prevent the escape of gas through the technological hole, the additional valve is closed. Then, the outlet of the syringe pre-filled with a self-vulcanizing sealant is docked to the entrance of the additional valve, after which the additional valve is opened, and the sealant is introduced into the interflange space and hairpins under pressure exceeding the gas pressure in the pipeline. After filling the interflange space and hairpins with a self-vulcanizing sealant, the additional valve is closed and the syringe is undocked. After the process of self-vulcanization of the sealant, the additional valve is removed, and the technological hole is closed.

The application of this method allows to eliminate gas leaks along the flange and studs of the connection without stopping the gas pumping. At the same time, this method can be effectively applied only on joints with ground flanges (for example, on flange joints of taps) having a relatively thin wafer space. In this case, the self-vulcanizing sealant is held in the interflange space until the self-vulcanization process is completed due to its viscosity. However, many flange connections (in particular, insulating) have a sufficiently large distance between the flanges, reaching several centimeters. In this case, it is difficult to create the required pressure in the interflange space, since the sealant will leak and be ejected by gas, which does not provide the required quality of sealing the connection.

The basis of the invention is the task of improving the quality of sealing a flange connection having a large distance between the flanges, without stopping the pumping of gas through the gas pipeline, by filling the interflange space with a self-vulcanizing sealant, at a pressure exceeding the gas pressure in the gas pipe, introduced through an additional valve using a syringe, with preliminary installation on the flange connection of the second additional crane, ring gasket and retaining ring. This will allow for more uniform filling of the interflange space with a self-vulcanizing sealant due to the fact that the presence of an annular gasket and a retaining ring prevents the release of self-vulcanizing sealant during its injection, and with the help of a second additional valve, the gas flowing out at that time is secured.

The problem is solved due to the fact that in the method of eliminating gas leaks through flange connections of gas pipelines without stopping gas pumping through a gas pipeline, which includes filling the interflange connection with a self-vulcanizing sealant introduced through an additional valve using a syringe under a pressure exceeding the gas pressure in the gas pipeline, according to the invention, first make a technological hole for an additional crane in the lower part of the flange, after which another technological hole is made in the upper part of the flange, in which fix the second additional valve, then both valves are opened, an annular gasket is inserted into the interflange space from the outside of the flange, and a retaining ring is put on the flange connection across the pipeline axis, after which, with the help of a syringe, into the interflange through an additional valve installed in the lower part of the flange the compound is injected with a self-vulcanizing sealant, and after the appearance of the sealant at the outlet of the second additional valve, the latter is closed and the pressure of the introduced self-vulcanizing germ ika greater than the gas pressure in the pipeline, with the sealant after samovulkanizatsii additional valves removed, and the hole is closed. When performing work in cold weather, when the viscosity of the sealant increases, the self-vulcanizing sealant is injected into the interflange space using a syringe sequentially through both additional valves.

The essence of the method is illustrated in figures 1-3.

Figure 1 explains the operation of the proposed method "securing additional cranes" where 1 - flanges of the connection; 2 - pipeline; 3 - hairpin; 4 - a nut; 5 - sealing interflange rings; 6 - technological holes; 7 - additional cranes.

Figure 2 explains the operation of the proposed method "installation of an annular gasket and retaining ring" where 1 is the flanges of the connection; 2 - pipeline; 3 - hairpin; 4 - a nut; 5 - sealing interflange rings; 6 - technological holes; 7 - additional cranes; 8 - ring gasket; 9 - a retaining ring.

Figure 3 explains the operation of the proposed method "connecting the syringe and the introduction of the sealant" where 1 - flanges of the connection; 2 - pipeline; 3 - hairpin; 4 - a nut; 5 - sealing interflange rings; 6 - technological holes; 7 - additional cranes; 8 - ring gasket; 9 - retaining ring; 10 - a syringe; 11 - self-vulcanizing sealant.

The method is as follows. First, two holes are made in the flange from its outer side to the interflange gap, for example, in the lower and upper parts of the flange. After that, they install one additional crane. Further, to ensure the gas outlet, additional valves are opened, and an annular gasket is installed in the interflange gap on the outside of the flange. To fix the gasket on the flange put on a retaining ring. After that, the first additional valve installed in the lower part of the flange is closed, and a syringe pre-filled with self-vulcanizing sealant is connected to it. Next, this tap is opened and the sealant is introduced into the wafer gap. The second additional valve installed in the upper part of the flange, in this case plays the role of a drainage hole. After the appearance of the sealant at the outlet of the second additional valve, it is closed, and the injection of the sealant is continued, creating a pressure exceeding the gas pressure in the gas pipeline. After that, the first additional valve is closed, and the syringe is disconnected. After completion of the process of self-vulcanization of the sealant, additional valves are removed, and the holes are closed, for example, with plugs.

To prevent the sealant from escaping through the stud threads, conventional nuts can be replaced with well-known cap nuts (see, for example, GOST 9064-75 Nuts for flange connections).

When working at low ambient temperatures, the viscosity of self-vulcanizing sealant increases. In this case, to ensure uniform distribution of the self-vulcanizing sealant in the wafer during injection, after the sealant appears at the outlet of the second valve, a second syringe can be attached to it, pre-filled with a self-vulcanizing sealant. In this case, the filling of the interflange cavity is carried out sequentially using two syringes.

Using the proposed method will improve the quality of sealing due to a more uniform distribution of sealant in the wafer space of the connection.

The proposed method can be used in the gas industry to eliminate gas leaks on flanged joints of high pressure gas pipelines, as well as on flanged joints of steam pipelines, water and oil products.

Claims (2)

1. A method for eliminating gas leaks through flanged connections of gas pipelines without stopping gas pumping through the gas pipeline, which consists in filling a self-vulcanizing sealant through an additional valve in the interflange space, for which a technological hole is made from the outside of the flange to its interflange cavity, an additional valve is fixed in it, it is closed and attach to it a syringe pre-filled with self-vulcanizing sealant, an additional valve is opened and through it from the syringe to the interfl A self-vulcanizing sealant is introduced under pressure above the gas pressure in the gas pipeline, after self-vulcanization of which the additional valve is removed and the technological hole is closed, characterized in that the technological hole is first made for an additional valve in the lower part of the flange, and then in the upper part of the flange another technological hole in which the second additional valve is fixed, then both cranes are opened, into the interflange space from the outside of the flange an annular gasket is introduced, and a retaining ring is put on the flange connection across the axis of the pipeline, after which a self-vulcanizing sealant is introduced into the interflange connection through an additional valve installed at the bottom of the flange, after the appearance of the sealant at the outlet of the second additional valve, the latter is closed and pressure is applied introduced self-vulcanizing sealant in excess of the gas pressure in the gas pipeline, and after self-vulcanization of the sealant, the second additional valve is removed, and verst close. 2. The method according to claim 1, characterized in that after the appearance of the sealant at the outlet of the second additional valve, it is closed and a second syringe is connected to it, pre-filled with self-vulcanizing sealant, after which the filling of the interflange space is carried out by each syringe sequentially.

Images