JP2806438B2 - How to Repair Piping Leaks - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to a method for preventing leaks of pipes handling various fluids in various industries.

[Conventional technology]

In various industries such as the chemical industry, various kinds of liquids or gases are handled, so that pipes are used everywhere. Therefore, many pipes are used not only for factories in the manufacturing industry but also for gas lines for consumer tap water. A relatively familiar fluid,
More specifically, irrigation water, seawater, steam, tap water,
There are city gas, LPG, process liquid, crude oil, petroleum, etc.

In general, a piping line has a main pipe having an original role of transporting a fluid, and usually a small-diameter branch such as a drain line, a trap line, and a detection line for detecting a pressure, a flow rate, and the like of the fluid. The tube is extending. These branch pipes are also considered as ancillary parts in the whole piping line, but they are important for operation,
In particular, from the viewpoint of safety, it is a part that can be called the heart in a sense.

For example, a steam line of the chemical industry is used as a drain pipe from a main pipe, a trap line, a sampling line, and a pressure detection line, and may be used as a branch pipe to each plant. For tap water, it may be a line extending to each home. There are various sizes of this pipe, but most branch pipes are about 3 / 8B to 1B. The main process line may be the main line. These pipes may be covered with a heat insulating material, arranged on a rack, and water pipes and gas pipes may be buried in soil. And the connection part is connected by welding or screwing.

Materials for these pipes include SGP (gas pipe), STP
G (carbon steel pipe for pressure piping), STPT (carbon steel pipe for high temperature piping), STPA (alloy steel pipe for piping), SUS (stainless steel), etc. Various metal pipes are used depending on pressure, temperature and fluid. Have been. When these pipes are used for a long period of time, metal cracks due to dirt on the inner surface of the pipe, corrosion of the outer surface of the pipe due to rainwater, cracks due to freezing, leakage in the soil due to electrolytic corrosion, breakage due to load applied by cars etc. In some cases, serious troubles such as leakage due to damage due to contact with foreign matter may be caused. The leakage due to the corrosion often occurs from the outside of the pipe.

In the event that a liquid leak or a gas leak occurs in the pipe, as a countermeasure, the line is temporarily stopped and a part of the pipe is replaced by welding or the like in many cases. On the other hand, in order to prevent leakage without stopping the line, there is a method of applying a U-shaped split band to a pipe via a liquid packing.

[Problems to be solved by the invention]

However, in the above-mentioned conventional technique, in the method of replacing a part of the pipe by welding or the like, it is necessary to stop the transfer of the fluid in the pipe and release the pressure. As a result, in the utility line, all the plants connected to the utility line are stopped, and a large production loss is caused.
In addition, there is a problem that it takes more than one day to depressurize a large-sized pipe, and it takes a long time without releasing the pressure due to the leakage of an existing valve in the line, resulting in a very large labor.

On the other hand, in the method of applying the band, since the band is applied to the outflowing fluid portion, there is a problem that the pressure of the outflowing fluid is low and if it is not a very small amount, there is a danger to the worker and the work cannot be performed.

Therefore, the present invention has been made in view of the above circumstances, and an object of the present invention is to provide a pipe leakage prevention and repair method that can easily and safely prevent leakage of piping. It is in.

[Means for solving the problem]

In order to achieve the above object, in the present invention, the upstream side of the leaking part of the pipe is crushed over a plurality of stages, and the plurality of crushed parts sequentially form a narrow flow path in the downstream direction,
The orifice function of the crushed portion reduces the pressure of the fluid in the pipe. Then, in a state where the leakage of the fluid is substantially stopped, a closing member is attached to the pipe upstream of the leaked portion and downstream of the last crushed portion. It is characterized by stopping the leakage of water.

[Action]

In the present invention having the above-described configuration, the upstream side of the leaking pipe is crushed over a plurality of stages, and the plurality of crushed portions sequentially form a narrow flow path as going toward the leaked portion. When the fluid in the pipe is depressurized by the orifice function of the crushed part and the leakage of the fluid is almost stopped, a closing member is attached to the pipe upstream of the leaked part and downstream of the last crushed part, and finally By preventing the fluid from leaking, the piping can be easily and safely prevented from leaking in a short time while utilizing the fluid under pressure.

〔Example〕

Hereinafter, embodiments of the present invention will be described with reference to the drawings. FIG. 1 shows a connection example of pipes to which an embodiment of the present invention is applied. In the figure, a plurality of branch pipes 2a, 2b, 2c and 2d using a 3 / 4B SGP are connected to a 16B main pipe 1 through an elbow or the like as a draining line. Is provided with a drain valve 3. Here, for example, when leakage occurs due to corrosion caused by infiltration of rainwater into the branch pipe 2d on the primary side of the drain valve 3, leakage prevention repair of the pipe is performed according to the following procedure.

That is, as shown in FIG. 1, using a hydraulic crushing jig (not shown) at the position A of the branch pipe 2b, pressure is applied from the outside until the inner diameter of the branch pipe 2b is reduced by 50%, and the branch pipe 2b is crushed. As shown in the figure, a crushed portion 12a is formed. Next, the crushed portion 12a
Pressure is applied to the branch pipe 2b separated from the end by 150 mm or more until the inner diameter is reduced by 70% to form a crushed part 12b (third illustration). At this time, if the crushing direction is shifted by 90 degrees, the orifice function is further enhanced, and the decompression effect is increased.

Further, in the same manner as above, 150 mm from the end of the crushed portion 12b.
Pressure is applied to the branch pipe 2b spaced apart by at least mm to reduce the inner diameter by 80 to 90% to crush and form the crushed portion 12c. And
A pressure is applied to the branch pipe 2b separated from the end of the crushed portion 12c by 150 mm or more until the inner diameter is reduced by 95% or more, and crushed to form a crushed portion 12d (fourth illustration). At this time, it is necessary to perform the work accurately so as not to cause the piping to be cracked due to excessive deformation.

Next, a flange 4 is welded to a position B of the branch pipe 2c downstream of the crushed portion 12d of the last stage, and a bolt 5 and a nut are screwed to the flange 4 while a valve 5 as a closing member is opened. After the installation, the valve 5 was closed to finally stop the leakage of the pipe. Thereafter, the branch pipe 2d may be replaced with a branch pipe having no leakage.

In this way, for example, when hot water at a pressure of 23 kg / cm ² G and a temperature of 120 ° C. enters the 1 / 2B branch pipe, the fourth-stage crushed portion
The pressure around 12d became 0.15 kg / cm ² G or less, and the flange 4 could be welded. In addition, in the branch pipe without drain of the steam main line with a pressure of 3 kg / cm ² G, the flange 4 can be welded and the valve 5 can be attached only by forming the third-stage crushed portion 12c. The leak has stopped.

Therefore, according to the present embodiment, when the branch pipe 2d leaks due to corrosion, the upstream side of the leak portion of the branch pipe 2d is crushed over a plurality of stages,
The fluid in the branch pipe is depressurized by an orifice function (decompression effect) caused by gradually increasing the amount of crushing, and the flange 4 is attached to the branch pipe downstream from the last crushed portion in a state where the leakage is almost eliminated. By welding, the valve 5 is attached to the flange 4 in an open state, and then the valve 5 is closed and finally the leakage of the fluid is stopped, so that the fluid under pressure can be used easily and safely in a short time. The pipe can be prevented from leaking.

Here, the higher the fluid pressure in the pipe, the greater the number of stages in the crushed part, and theoretically, the greater the number of stages, the higher the pressure is possible, but at a pressure of 120 kg / cm ² G, 11 or more stages are required If the piping on the site is not long, the actual use is impossible.

The present invention is not limited to the above embodiment, and various modifications are possible. For example, in the above embodiment, the flange 4 was welded to the branch pipe 2c downstream of the crushed portion 12d at the last stage. A screw is engraved on the outer periphery of the cap and a cap as a closing member is attached to stop leakage, or a wooden plug, a copper plug, a lead plug, or the like as a closing member is directly pressed into the opening end to which the flange is welded. Leakage may be stopped.

〔The invention's effect〕

As described above, according to the present invention, it is possible to easily and safely repair pipes in a short time and safely without incurring a large production loss while utilizing a fluid under pressure. To play.

[Brief description of the drawings]

FIG. 1 is a system diagram showing a connection example of pipes to which an embodiment of the present invention is applied. FIG. 2 is a cross-sectional view of pipes to which an embodiment of a method for repairing and preventing leaks of pipes of the present invention. FIG. 4 is a sectional view taken along the line III-III of FIG. 2, and FIG. 4 is a sectional view taken along the line IV-IV of FIG. 1 ... main pipe, 2a, 2b, 2c, 2d ... branch pipe, 3 ... drain valve, 4 ... flange, 5 ... valve (closing member).

Claims (1)

(57) [Claims] 1. An upstream side of a leak portion of a pipe is crushed over a plurality of stages, and the plurality of crushed portions sequentially form a narrow flow path in a downstream direction, and a fluid in the pipe is formed by an orifice function of the crushed portion. Pressure reduction, and then in a state where the leakage of the fluid is substantially stopped, a closing member is attached to the piping on the upstream side of the leaking part and on the downstream side of the crushed part at the last stage, and finally the leakage of the fluid is stopped. Leak prevention repair method.