RU2208196C2 - Method of elimination of gas leaks past flanged connections of rotary valves in gas conduits without stoppage of gas pumping along conduit - Google Patents

Abstract

FIELD: civil engineering. SUBSTANCE: invention can be used in servicing and repair of gas conduits. Blind dummy hole is made in flange of rotary valve in which additional rotary valve is secured through which dummy hole is extended to reach interflange space or pin cup and then sealing compound is pressure-fed into interflange space and pin cups, said pressure exceeding gas pressure in gas conduit. Then additional rotary valve is removed, and dummy hole is closed. To preclude getting out of sealing compound in process of pressure feeding, flange, pin cups and nuts from outer side of rotary valve are treated with catalyst. EFFECT: improved reliability of flange joints of rotary valves. 2 cl, 7 dwg

Description

 The invention relates to techniques for repairing gas pipeline taps, mainly high-pressure gas pipelines.

 To control the gas pumping process throughout the pipelines, full-sized valves are installed that are technologically connected to the pipes by means of a flange connection tightened by studs.

 During operation of gas pipelines, the flange connections of the valves 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 ring occurs, its deformation and cracking, which in turn leads to gas leaks. This phenomenon is illustrated by the drawing shown in FIG. 1, where 1 is the casing of the crane; 2 - flange connection of the crane; 3 - pipeline; 4 - hairpin; 5 - a nut; 6 - hairpin glass; 7 - sealing interflange rings; 8 - gas leaks.

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

 A known 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 gas pipeline valves (see. Technological instruction for eliminating gas leaks at gas pipeline cranes. Order of UkrGazprom 341 dated 12.12.97). 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 glass. 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 flanged connections of gas pipeline valves without stopping gas pumping through the pipeline by filling the interflange space and the valve cups of the valve with a self-vulcanizing sealant (see Pipeline gas pipelines. Eliminating gas leaks through flange connections with PST-562 polyurethane compound. Technological instruction. - Kiev: RVPP "Bohemia", 1996). The method is a prototype of the claimed invention. The method is as follows. The valve flange nut is loosened and the hairpin cup is filled with a self-vulcanizing sealant. After that, an insert sealing the sealant is screwed onto the hairpin deep into the hairpin glass. After that, the nut is tightened. These operations are carried out sequentially for all studs of the flange connection of the crane. The sealant used has the property of volumetric physical expansion during solidification; therefore, during the vulcanization process, the sealant fills the interflange space and shells, as a result of which gas leaks cease.

 The essence of the method selected as a prototype is illustrated by the drawing shown in FIG. 2, where 1 is the casing of the crane; 2 - flange connection of the crane; 3 - pipeline; 4 - hairpin; 5 - a nut; 6 - hairpin glass; 7 - sealing interflange rings; 9 - self-vulcanizing sealant; 10 - insert.

 The method allows to eliminate gas leaks, both on the stud and on the flange, however, it is time-consuming (due to the need to consistently loosen all nuts). Cranes of underground pipelines are under a layer of soil, stand on a concrete base and are covered with an anticorrosion coating, which complicates access to all nuts of the flange connection. In some cases, for example, the location of pipeline valves under water or in a swamp, the application of this method without additional measures is difficult. In addition, there is an uneven filling of the interflange space with a sealant, since the seal is created exclusively due to its self-expansion, and its simultaneous introduction into all hairpins without stopping the gas pumping through the pipeline is impossible.

 The present invention is aimed at achieving the following technical results: improving the quality of sealing a flange joint and improving the processability of eliminating gas leaks through flanged joints of gas pipeline valves without stopping gas pumping through the pipeline by filling the interflange space and hairpin glasses of the valve with a self-vulcanizing sealant.

 The purpose of the invention is achieved by the fact that a self-vulcanizing sealant is introduced into the wafer space and the valve cups of the valve under a pressure higher than the gas pressure in the pipeline, using a syringe through an additional valve installed in a pre-made technological hole.

 The invention consists in the following.

 First, a blind technological hole is made in the valve flange, in which an additional valve, for example, a ball type, is fixed. After that, the additional valve 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, an 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 a 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 sealant hardens, the additional valve is removed, and the technological hole is closed.

 To prevent the exit of the sealant through the shells of the flange, studs and nuts during its pumping, the flange, studs and nuts on the outside of the valve can be further treated with a catalyst that locally accelerates the curing process of the sealant. The catalyst may be introduced in any known manner, for example, by spraying under pressure.

 The invention is illustrated by the drawings shown in figures 1-8.

 Figure 1 explains the mechanism of gas leaks at the flange connection of the valve, where 1 is the casing of the valve; 2 - flange connection of the crane; 3 - pipeline; 4 - hairpin; 5 - a nut; 6 - hairpin glass; 7 - sealing interflange rings; 8 - gas leaks.

 FIG. 2 illustrates a method for eliminating gas leaks, selected as a prototype, where 1 is the casing of the tap; 2 - flange connection of the crane; 3 - pipeline; 4 - hairpin; 5 - a nut; 6 - hairpin glass; 7 - sealing interflange rings; 9 - self-vulcanizing sealant; 10 - insert.

 FIG. 3 illustrates the operation of the proposed method "making a blind technological hole in the crane flange", where 1 is the casing of the crane; 2 - flange connection of the crane; 3 - pipeline; 4 - hairpin; 5 - a nut; 6 - hairpin glass; 7 - sealing interflange rings; 11 - blind technological hole.

 FIG. 4 explains the operation of the proposed method "securing an additional crane", where 1 is the casing of the crane; 2 - flange connection of the crane; 3 - pipeline; 4 - hairpin; 5 - a nut; 6 - hairpin glass; 7 - sealing interflange rings; 11 - a blind technological hole; 12 - additional crane.

 FIG. 5 illustrates the operation of the proposed method "extension of the technological hole to the interflange space", where 1 is the casing of the crane; 2 - flange connection of the crane; 3 - pipeline; 4 - hairpin; 5 - a nut; 6 - hairpin glass; 7 - sealing interflange rings; 12 - additional crane; 13 - technological hole.

 FIG. 6 illustrates the operation of the proposed method "fitting the syringe", where 1 is the casing of the tap; 2 - flange connection of the crane; 3 - pipeline; 4 - hairpin; 5 - a nut; 6 - hairpin glass; 7 - sealing interflange rings; 9 - self-vulcanizing sealant; 12 - additional crane; 13 - technological hole; 14 - a syringe.

 FIG. 7 explains the operation of the proposed method "the introduction of self-vulcanizing sealant", where 1 is the casing of the crane; 2 - flange connection of the crane; 3 - pipeline; 4 - hairpin; 5 - a nut; 6 - hairpin glass; 7 - sealing interflange rings; 9 - self-vulcanizing sealant; 12 - additional crane; 13 - technological hole; 14 - a syringe.

 Using the proposed method allows to improve the sealing quality of the flange connection due to a more uniform filling of the interflange space of the crane and the connected hairpin glasses with a self-vulcanizing sealant. In addition, the process of eliminating gas leaks is simplified due to the fact that there is no need to unscrew all the nuts, it is enough to have access to only one point of the flange.

 The proposed method can be used in the gas industry to eliminate gas leaks on flange joints and studs of taps of high pressure gas pipelines.

Claims (2)

 1. A method of eliminating gas leaks through flange connections of gas pipeline valves without stopping gas pumping through the gas pipeline, which consists in filling the valve flange space and the valve cups with a self-vulcanizing sealant, characterized in that a blind technological hole is made in the valve flange in which an additional valve is fixed through which the technological hole is extended to the interflange cavity or the hairpin of the crane, after which the additional valve is closed and connected to it dissolved syringe prefilled vulcanising sealant further additional valve is opened and through it from the syringe and the space in the wafer hairpin glasses at a pressure above the gas pressure in the pipeline is introduced vulcanising sealant after curing which additional valve is removed, a process opening is closed.  2. A method for eliminating gas leaks through flange connections of gas pipeline valves without stopping gas pumping through the gas pipeline according to claim 1, characterized in that the flange connection, studs and nuts on the outside of the valve are treated with a catalyst at the same time as self-vulcanizing sealant is introduced into the interflange space and hairpins.

Images