JP2001041400A - Fluid leaking position detecting method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To make to detect the leaking position of a fluid in a fluid pipe line buried under the ground or in an insulated fluid pipe line, securely in a good efficiency. SOLUTION: In a fluid pipe line or an insulated fluid pipe line, a bag form plug body 7 having an air hose 9 is drawn in at a constant distance inside a pipe 1 in the contracted condition, from one side opening end of the pipe 1, and the air is fed to expand the plug body 7, to contact closely to the inner surface of the pipe 1, while one side opening end of the pipe 1 is blocked by a blocking member 12, and a compressed air is fed to the closed inner space of the pipe 1 until the pressure is made in a constant inner pressure, so as to check the condition of the reduction of the pressure in the inner space by an inner pressure indicator 15. When there is no reduction of pressure, the plug body 7 is moved to the inner side of the pipe 1 at a fixed distance by contracting the plug body 7, and it is expanded again to feed the compressed air to the inner space of the pipe 1, so as to check the condition of the pressure reduction in the inner space. Such a work is repeated until a pressure reduction is generated, and it is decided that a fluid leaking position exists between the position of the plug body 7 when the pressure reduction is generated, and the position of the plug body 7 when the pressure reduction is not generated immediately before that.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for efficiently and reliably detecting a leak position of a fluid in a fluid pipe or a heat insulating fluid pipe buried underground.

[0002]

2. Description of the Related Art A pipe through which a fluid such as high-temperature water flows is buried in the ground by surrounding the pipe with a heat insulating material and a sheath pipe so that the temperature of the fluid does not drop. In such an insulated fluid line, the inspection, repair, cleaning, etc. of the inside of the tube can be easily performed.
Usually, artificial pits are provided over a span of 50 m or more.

[0003] In the case of such a long insulated fluid pipeline, a long pipe must be manufactured on site by welding several pipes of a constant length. The fluid will leak from there. Further, even if the pipe is corroded and a hole is formed, the fluid leaks out.

[0004]

When the fluid leaks from the heat-insulating fluid pipe as described above, it is difficult to find the leak position even if a camera is inserted into the pipe. Particularly, in the case of a small pinhole, It is almost impossible to find. However, even if the ground is dug to expose the insulating fluid pipe, the leak location cannot be found because the pipe is surrounded by the heat insulating material and the sheath pipe.

[0005] Under such circumstances, various methods for detecting the leakage position of the fluid in the adiabatic fluid line using a temperature sensor, a microphone, or the like are being studied in the related industries. However, at present, no method has been proposed for efficiently and reliably detecting a leak position.
Similarly, even in a fluid conduit in which a pipe for flowing a fluid is buried underground, a method capable of efficiently and reliably detecting a leak position has not been proposed.

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide an epoch-making detection method capable of efficiently and surely detecting a leak position of a fluid in an adiabatic fluid pipe or a fluid pipe. Is to provide.

[0007]

In order to achieve the above object, a method of the present invention is to provide a fluid pipe in which a pipe for flowing a fluid is buried in the ground or a heat insulating material and a sheath around the pipe for flowing a fluid. A method of detecting a leakage position of a fluid in an insulated fluid pipe buried in the ground surrounded by a pipe, and from one open end of the pipe,
A bag-shaped plug with an air hose is drawn into the pipe in a contracted state by a certain distance, and compressed air is supplied through an air hose to expand the bag-shaped plug and adhere to the inner surface of the pipe. One of the open ends is closed with a closing member, compressed air is supplied to the sealed internal space of the pipe until a constant internal pressure is reached, and an internal pressure indicator checks whether or not the internal space pressure has decreased. If not, it is judged that there is no fluid leakage, and the bag-like plug is degassed and deflated, moved to the back of the pipe by a certain distance, and the plug is supplied and expanded again, so that the inner surface of the pipe is Closely contacted, supply compressed air again to the sealed internal space of this pipe until a constant internal pressure is reached, check the internal pressure indicator for a decrease in internal pressure, and then repeat the above operation until there is a pressure decrease. Stopper when pressure drops repeatedly Position and, between the position of the stopper when the pressure decreased immediately before did not occur, is characterized in that it is determined that there is leakage location of the fluid.

As in the detection method of the present invention, the presence or absence of a pressure decrease in the closed internal space of the pipe is examined by moving the bag-shaped plug at a fixed distance and if there is a leaking portion of the fluid, However, even if it is something like a pinhole, a pressure drop will always occur, so the leak position can be detected reliably, and the shorter the travel distance of the plug, the more accurate the leak position detection will be. Will be improved.

[0009]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, specific embodiments of the present invention will be described in detail with reference to the drawings.

FIGS. 1 to 3 are explanatory views of a leak position detecting method according to an embodiment of the present invention. FIG. 1 shows a method in which a flange joint pipe in an artificial pit is removed, and a pull-in rope is passed through the pipe. FIG. 2 shows a state in which a bag-shaped plug in a contracted state is pulled into the pipe with a rope.
FIG. 3 shows a state in which compressed air is supplied to the closed internal space of the tube by expanding the bag-like plug drawn into the tube.

In FIG. 1 to FIG. 3, reference numeral 1 denotes a pipe through which a fluid in a heat insulating fluid pipe flows, and the pipe 1 is surrounded by a heat insulating material 2 and a sheath pipe 3 and buried in the ground. In addition, artificial pits 4 and 4 made of concrete are provided in the heat-insulating fluid pipe at a span of 50 m or more so that the internal inspection, repair, cleaning, and the like of the pipe 1 can be easily performed.

According to the leak position detecting method of this embodiment, first, as shown in FIG. 1, the flange joint pipes 5 and 5 in the artificial pits 4 and 4 are removed, and the pipe 1 whose leak position is to be detected. Both ends are opened, and the rope 6 for pulling in the plug is inserted into the pipe 1.

Then, as shown in FIG. 2, the rope 6 is tied to a bag-shaped plug 7, and while the rope 6 is wound by a winder 8, the plug 7 with the air hose 9 is connected to one end of the tube 1. From the open end of the tube 1 to the inside of the tube 1 by a certain distance. The air hose 9 is wound around a feeder 10. When an air pump 11 connected to the feeder 10 is operated, air can be supplied to the plug 7 through the air hose 9.

Next, as shown in FIG.
Is actuated to release air through the air hose 9 into the bag-like plug 7.
To expand the bag-like plug 7 to make the tube 1
And an open end of the tube 1 is closed by a closing member 12. The air pressure of the plug 7 is 0.5 to 3 k
g / m ² is appropriate, and when the pressure is adjusted to this level, the plug 7 comes into close contact with the inner surface of the tube 1, and even if compressed air is introduced into the internal space of the tube 1 as described later, the plug 7 There is no worry about the body 7 moving.

The plug 7 used in this embodiment is a gourd-shaped synthetic rubber or soft plastic plug whose center is narrowed, and can be tightly adhered to the inner surface of the tube 1. The bag-shaped plug is not limited to the gourd-shaped plug of this embodiment, and any plug-shaped plug, such as a spindle-shaped or column-shaped plug, that can be airtightly adhered to the inner surface of the tube 1 can be used. is there.

When the internal space of the pipe 1 is sealed by the plug 7 and the closing member 12 as described above, the air supply hose 14 from the compressor 13 is connected to the inlet of the closing member 12,
By operating the compressor 13, compressed air is supplied to the closed internal space of the pipe 1 to have a constant internal pressure. If the internal pressure is too high, the plug 7 may move or the closing member 12 may come off. Therefore, the internal pressure is set to about 1 kg / m ² while watching the internal pressure indicator (pressure gauge) 15. It is desirable to do.

When the setting of the internal pressure is completed, the internal pressure indicator 15 checks whether or not the pressure in the internal space of the pipe 1 has decreased. If there is a pressure decrease, it can be determined that there is a fluid leakage position from the end of the tube 1 to the position of the plug 7, so that that portion can be immediately repaired to stop fluid leakage.

If there is no pressure decrease, it is determined that there is no fluid leakage, the plug 7 is evacuated and contracted, and while the rope 6 is wound up by the winder 8, the plug 7 is further fixed as shown by a virtual line. Is moved to the back of the pipe 1 by the distance of. By operating the air pump 11 again, the plug 7 is inflated and brought into close contact with the inner surface of the tube 1, and compressed air is supplied from the compressor 13 to the sealed internal space of the tube 1 until a constant internal pressure is reached. While looking at the internal pressure indicator 15, the presence or absence of a pressure decrease in the internal space is checked.

Thereafter, the above operation is repeated until the pressure in the internal space decreases. When a pressure decrease in the internal space occurs, it is determined that there is a fluid leakage position between the position of the plug 7 at that time and the position of the plug 7 immediately before the pressure decrease does not occur. As a result, the ground at that portion can be dug up and repaired efficiently. That is, assuming that a pressure decrease occurs when the plug 7 is at the position indicated by the imaginary line, for example, the position between the position of the plug 7 indicated by the imaginary line and the position of the plug 7 indicated by the solid line immediately before that. Since it can be determined that there is a leak position, the ground in the meantime can be dug up to partially repair the heat-insulating fluid pipe efficiently.

As in the above leak position detection method, the bag-like plug 7 is moved within the tube 1 by a predetermined distance, and the presence or absence of a pressure decrease in the closed internal space of the tube 1 is sequentially examined. Therefore, if there is a place where the fluid leaks out, the pressure will necessarily decrease, so that the leaking position of the fluid can be reliably detected, and the shorter the moving distance of the plug 7, the higher the detection accuracy. Will be. However, if the moving distance of the plug 7 is too short, the efficiency of the detection operation is reduced and a long time is required.
It is desirable to set the distance to about 0 m to achieve both detection accuracy and work efficiency.

In the above embodiment, the case where the leak position of the fluid in the adiabatic fluid pipeline is detected has been described. However, the detection method of the present invention employs a fluid pipeline in which a fluid flowing pipe is buried underground. In the case of detecting the leak position of the fluid in the above, the present invention can be similarly applied.

[0022]

As is apparent from the above description, according to the method for detecting a leaked position of a fluid according to the present invention, the leaked position of a fluid can be reliably and efficiently detected, the operation is simple, and the detecting operation is simple. Since no special device or equipment is used, a remarkable effect that it can be implemented easily and inexpensively is obtained.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a leak position detecting method according to an embodiment of the present invention, showing a state in which a flange joint pipe in an artificial pit is removed and a pull-in rope is passed through the pipe.

FIG. 2 is an explanatory diagram of the leak position detecting method according to the embodiment, and shows a state in which a bag-shaped plug in a contracted state is pulled into a pipe by a rope.

FIG. 3 is an explanatory view of the leak position detecting method according to the embodiment, showing that a bag-like plug drawn into the pipe is expanded to supply compressed air to a closed internal space of the pipe. It is.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Pipe for flowing fluid 2 Insulation material 3 Sheath tube 4 Artificial pit 6 Rope for drawing in plug 7 Bag-shaped plug 9 Air hose 11 Air pump 12 Closing member 13 Compressor 15 Internal pressure indicator (pressure gauge)

Claims (1)

[Claims] 1. A fluid conduit in which a pipe for flowing a fluid is buried underground.
Alternatively, a method of detecting a leak position of a fluid in an insulated fluid pipe buried in the ground by surrounding a pipe through which a fluid flows with a heat insulating material and a sheath pipe, and detecting an air hose from one open end of the pipe. The bag-shaped plug attached to the tube is retracted by a certain distance into the tube in a contracted state, and air is supplied through an air hose to inflate the bag-shaped plug and adhere to the inner surface of the tube. The open end is closed with a closing member, compressed air is supplied to the sealed internal space of the pipe until a constant internal pressure is reached, and the internal pressure indicator checks whether or not the internal pressure has decreased. It is determined that there is no leakage, and the bag-shaped plug is evacuated and deflated, moved to the back of the pipe by a certain distance, and the plug is supplied and expanded again to make it close to the inner surface of the pipe, Compress air again into the closed interior space of this tube. The internal pressure indicator is used to check whether the pressure in the internal space has decreased.Then, the above operation is repeated until the pressure decreases, and the position of the plug when the pressure decreases and the immediately preceding position A method for detecting a leak position of a fluid, wherein it is determined that there is a leak position of the fluid between the position of the plug when no pressure reduction occurs.