JP2005233314A - Stopping method of pipe - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a stopping method of a pipe, passing an expansion plug even through a bent part of the pipe without obstacle and stopping up the pipe in front of the bent part. <P>SOLUTION: In implementing this stopping method of a pipe by inserting the expansion plug 10 including a rubber expansion pipe 12 as the main component in the interior of the pipe 52, and expanding the rubber expansion pipe 12 in the radial direction by pressurized fluid supplied to the interior of the rubber expansion pipe 12 to stop up the pipe 52 and shut off the pipeline, the shape of the vulcanized rubber expansion pipe 12 is set flat, and after the expansion plug 10 is inserted in the pipe 52 kept in the flat shape, the pressurized fluid is supplied to expand the rubber expansion pipe 12, thereby stopping up the pipe 52. <P>COPYRIGHT: (C)2005,JPO&NCIPI

Description

  The present invention relates to a pipe sealing method in which, for example, a gas pipe or the like buried in the ground is plugged at a certain location to shut off the pipe, and more specifically, when a fluid leaks due to a hole in the pipe. The present invention relates to a piping sealing method that is suitable for application when examining a leaking portion.

For example, in the case of a gas pipe buried in the ground, if a hole or a crack or crack occurs in the gas pipe due to aging or other reasons, the internal gas leaks to the outside.
When such a gas leak occurs, it is necessary to urgently find out the location of the gas leak and repair the gas piping.

Conventionally, when such a gas leak occurs, the location of the gas leak is registered from the odor of the gas leaked to the periphery, and the soil is dug over a wide range L as shown in FIG. The gas pipe 200 was exposed to find and repair the gas leak location.
However, in this case, a large amount of soil must be dug over a wide range L, which increases the amount of work and the work time, making it difficult to take urgent countermeasures.

  As a method of finding and identifying the gas leakage location of the gas pipe 200, an expansion plug 202 is inserted into the gas pipe 200 as shown in the comparative example diagram of FIG. A method for examining a gas leakage location by inflating and sealing the gas pipe 200 and detecting the pressure in the gas pipe 200 in front of the gas pipe 200 has been studied by the present applicants (for example, Japanese Patent Application No. 2003-189103: Release).

If the gas leaking part is ahead of the sealing plug part by the expansion plug 202, that is, if leaking in front of the expansion plug 202, the airtight test pressure applied to the front of the sealing plug part from the inner pipe passing through the expansion plug 202 is timed. It can be seen that there is a leak point.
Then, the expansion plug 202 is repeatedly expanded and contracted, and the plugged portion is sequentially moved forward. When the plugged portion reaches a position ahead of the gas leaked portion, the decrease in the airtight test pressure is eliminated and the detected pressure is detected. Since the pressure becomes a constant pressure, it becomes possible to pinpoint the gas leakage location based on the feed amount of the expansion plug 202.

If the gas leak location can be pinpointed in advance in this way, the range of digging back can be reduced when digging up the soil, so the amount of digging up of the soil is reduced, and the gas pipe 200 is reduced in a short time with a small amount of work. The repair work can be completed.
However, this method can be applied to the straight pipe portion of the gas pipe, but if the gas pipe has a bent portion (see 52A in FIG. 10), the expansion stopper hits the bent portion and stops there. Therefore, there is a problem that it is difficult to insert the expansion plug further back (forward) along the bent portion, that is, to feed it.

  As such an expansion plug, a rubber expansion pipe provided as a main element and the rubber expansion pipe expanded in the radial direction can be suitably used. In this case, the rubber expansion pipe has flexibility. Therefore, although it seems that the rubber expansion tube follows the bent portion and passes through the bent portion, it is actually shown in FIGS. 16 (A) and 16 (B). Thus, when the rubber expansion tube 204 having a straight tubular shape and a circular cross section reaches the bent portion, the rubber expansion tube 204 is broken halfway and cannot be fed further forward.

  The above expansion plugs can of course be used not only for investigation and identification of gas leaking locations, but also for the purpose of simply plugging gas piping at a certain location and blocking the pipeline. There is a problem that it is difficult to feed the stopper forward along the bent portion of the gas pipe, and therefore the gas pipe cannot be sealed in front of the bent portion.

  Although the problem has been described above by taking the gas pipe as an example, the same problem is a problem that may occur in common in water pipes and other pipes.

In addition, there exists what was disclosed by the following patent document 1 as a prior art relevant to this invention.
The thing disclosed in this Patent Document 1 relates to a pipe line blocking method, which is to insert an inflatable bag into a gas pipe and inflate it to close the gas pipe. In the method disclosed in No. 1, the inflatable bag cannot be fed along the bent portion of the gas pipe, and the problem of the present invention cannot be solved.

JP 2003-232486 A

  The present invention is based on such circumstances, and a pipe sealing method that can feed an expansion plug along a bent portion of a pipe without hindrance and can plug the pipe at a position in front of the bent portion. It was made for the purpose of providing.

  Thus, according to the method of claim 1, an expansion stopper having a rubber expansion pipe as a main element is inserted into the pipe, and the rubber expansion pipe is radially expanded by a pressurized fluid supplied to the inside of the rubber expansion pipe. A method of sealing a pipe for inflating and sealing the pipe to block the pipe, wherein the rubber expansion pipe has a flat shape after vulcanization, and the expansion plug is held while the flat shape is maintained. After being inserted into the pipe, the pressurized fluid is supplied to inflate the rubber expansion tube to seal the seal.

  The method of claim 2 is characterized in that, in claim 1, the pipe has a bent portion, and the expansion plug is inserted into the pipe along the bent portion to seal the plug.

  According to a third aspect of the present invention, in any one of the first and second aspects, the expansion plug is inserted into the pipe in a state in which the inside of the rubber expansion pipe is sucked with a negative pressure.

  The method according to claim 4 is the method according to any one of claims 1 to 3, wherein the expansion plug forms a double tube of the rubber expansion tube and an inner tube inserted into the rubber expansion tube. The present invention is characterized in that it is configured as a conducting pipe for detecting the pressure in the pipe in front of the tight plug location of the pipe by the stopper.

Effects and effects of the invention

  As described above, the present invention configures an expansion plug with the rubber expansion pipe as a main element, and the rubber expansion pipe is vulcanized in a flat shape, and the expansion plug is piped while maintaining the flat shape. After being inserted into the interior, the rubber expansion pipe is expanded by supplying pressurized fluid to seal the pipe.

As described above, when the rubber expansion tube is held in a cylindrical shape with a circular cross section, if the rubber expansion tube is fed along the bent portion of the pipe, the rubber expansion tube is bent halfway and cannot pass through the bent portion.
This is because, once the rubber expansion tube is deformed at a specific location, stress concentrates on the deformed location, and the deformation becomes larger and eventually the entire rubber expansion tube is bent at the specific location.

  However, in the present invention, the rubber expansion tube is vulcanized into a flat shape and inserted into the pipe while maintaining the flat shape. For example, when the rubber expansion tube reaches a bent portion, the rubber expansion tube is good. Because of its flexibility, it does not cause a phenomenon such as bending at a specific part, stress is well distributed throughout the rubber expansion tube, and the flat rubber expansion tube is good along the shape of the bent portion Can be deformed to follow. Therefore, it can pass through the bent portion without any trouble.

  Although the present invention is applicable when sealing a straight pipe portion in a pipe, as is clear from the above description, the present invention has a pipe having a bent portion, and an expansion plug is provided along the bent portion. This is particularly effective when it is necessary to seal the pipe by inflating it in the pipe and then sealing it (claim 2).

  Next, the third aspect of the present invention is such that the expansion plug is inserted into the pipe in a state in which the inside of the rubber expansion pipe having a flat shape after vulcanization is sucked with a negative pressure. An expansion tube can be made into a flat shape more favorably, and the advantage which can improve the insertability in the inside of piping, especially the insertability at the time of inserting along a bending part is acquired.

  According to a fourth aspect of the present invention, the expansion plug has a double-pipe structure composed of the rubber expansion pipe and an inner pipe inserted into the expansion pipe, and the inner pipe is used to detect and detect the pressure in the pipe ahead of the tight plug location of the pipe in the expansion plug. The expansion plug according to claim 4 can be suitably used for detecting the pressure in front of the pipe after sealing the pipe and investigating and identifying the leaked part of the pipe. .

Next, an embodiment in a case where the present invention is applied to a method for investigating and identifying a gas leakage location in a gas pipe will be described in detail based on the drawings.
1-4, 10 is an expansion plug for sealing the gas pipe 52 (see FIG. 5) by the expansion action in the radial direction, and 12 is a rubber expansion pipe constituting its main element.
As shown in FIGS. 2 and 3, the rubber expansion tube 12 has a laminated structure of an inner rubber layer 14, an outer fiber reinforcement layer 16, and an outermost outer rubber layer 18.

In this embodiment, the rubber expansion tube 12 has a flat shape as shown in FIG. 4 after vulcanization.
Incidentally, in this embodiment, the dimension of the width W in FIG. 4 in the rubber expansion tube 12 is 50 mm, and the dimension T in the direction perpendicular to this is 15 mm.
In this embodiment, the total length of the rubber expansion tube 12 is about 270 mm, and the length from the rear end of the rear end side guide 34 described later to the front end of the front end side guide 30 is about 350 mm.

  Cylindrical end fittings 20 and 22 each having an axial insertion hole at the center are inserted into the front end portion and the rear end portion of the rubber expansion tube 12, and the outer peripheral surfaces of these end fittings 20 and 22. On the other hand, the front-end | tip part and rear-end part of the rubber expansion pipe 12 are each airtightly fixed by the metal crimping rings 24 and 26 distribute | arranged to the outer side.

In this embodiment, the expansion plug 10 has a resin-made guide 30 having a generally warhead shape with an opening 28 at the tip, and the guide 30 is screwed to the end fitting 20. .
The rear end portion also has a resin-made guide 34 having a substantially warhead shape having an opening 32, and the guide 34 is attached to the end fitting 22 fixed to the rear end portion of the rubber expansion tube 12. It is fixed with screws.

These guides 30 and 34 serve as movement guides when the expansion plug 10 is moved inside the gas pipe 52, and have a maximum diameter portion larger than that of the rubber expansion pipe 12.
By providing such guides 30 and 34 at the front end portion and the rear end portion of the expansion plug 10, when the expansion plug 10 is moved in the gas pipe 52, the rubber expansion pipe 12 and the inner surface of the gas pipe 52 Thus, the expansion plug 10 can be smoothly moved in the front-rear direction within the gas pipe 52 without causing a large resistance due to the contact.

Inside the rubber expansion pipe 12, a conduction pipe (inner pipe) 36 for taking out and detecting the pressure in the gas pipe 52 is provided in a state of being inserted through the rubber expansion pipe 12 in the axial direction. 10 has a double tube structure of the conducting tube 36 and the rubber expansion tube 12.
The conducting pipe 36 is inserted through the end fitting 22 at the rear end of the rubber expansion pipe 12 and extends rightward (front end side) in the figure, and further, the front end side is the end of the front end of the rubber expansion pipe 12. The metal fitting 20 is inserted and protrudes forward (rightward in FIG. 2) from the end metal fitting 20, and the protruding portion is fixed and held by the metal fittings 38 and 40.

In FIG. 2, reference numeral 42 denotes an air tube for supplying pressurized air to the inside of the rubber expansion tube 12, which is disposed outside the conducting tube 36 so as to form a double tube.
And the front-end | tip part is being fixed to the edge part metal fitting 22 of the rear-end part of the rubber expansion pipe 12 with the metal fitting 43. FIG.
The rear end of the air tube 42 is fixed to the branch metal fitting 44 by a metal fitting 45.
The branch metal fitting 44 has an air branch passage 46, and a tip portion of a separate air pipe 48 is connected and fixed thereto by a metal fitting 49.
The other end of the air tube 48 is connected to an air pressure source such as an air compressor, and pressurized air from the air pressure source is supplied into the rubber expansion tube 12 through the air tube 48, the branch fitting 44, and the air tube 42. It is like that.

On the other hand, the conducting pipe 36 extends through the branch metal fitting 44 in the axial direction as it is, and the rear end side is connected to the pressure detection device.
Here, the insertion portion of the branch metal fitting 44 is fixed to the branch metal fitting 44 by the metal fitting 50.

  In the expansion plug 10 of the present embodiment, when pressurized air is supplied into the rubber expansion tube 12 through the air tubes 48 and 42, the rubber expansion tube 12 is radiated in the radial direction as shown in FIG. It expands outward, and the gas pipe 52 is sealed to block the pipeline.

6 and 7 show an example of a method for manufacturing the rubber expansion tube 12 in the expansion plug 10 in the order of steps.
In this manufacturing method, first, an unvulcanized rubber hose is wound around a mandrel 54 having a circular cross section.
Then, in the primary vulcanization step of FIG. 6 (I), this is primary vulcanized in a vulcanizing furnace.
In this primary vulcanization, a cylindrical unvulcanized product is put in a semi-vulcanized state (primary vulcanized product 13A).

Next, this is flattened in the flattening step of FIG.
Specifically, here, the cylindrical primary vulcanized product 13A is pressed using two iron plates 56, and this is formed into a flat shape.
Next, in the secondary vulcanization step of FIG. 7 (III), this is secondary vulcanized in a vulcanizing furnace.

  Thereafter, in the metal fitting installation step shown in FIG. 7 (IV), the end metal fittings 20 and 22 are inserted into the front end portion and the rear end portion of the rubber expanded pipe 12 after the secondary vulcanization, and then the caulking rings 24 and 26 are used. This is fixed to each end of the rubber expansion tube 12 by fastening.

The manufacturing method described above is suitable for manufacturing a rubber expansion tube 12 having a medium diameter, but when the rubber expansion tube 12 has a large diameter, a flat shape is preferable by the method shown in FIG. .
As shown in the drawing, the end member 60 for suction is attached to the cylindrical primary vulcanized product 13 </ b> A and the inside is vacuum-sucked, and this is constrained to a flat shape by the iron plate 58.
In this state, the secondary vulcanization is completed by heating for a predetermined time while maintaining the restrained state in the next secondary vulcanization step.

FIG. 9 shows an example of flattening suitable for the case where the rubber expansion tube 12 has a small diameter. Here, as shown in the drawing, a cylindrical primary vulcanized product 13A is wound around a mandrel 62 having a large diameter. Flatten.
In this state, the primary vulcanized product 13A, which is formed into a flat shape by wrapping the cloth tape 64 around the outer peripheral side, is constrained to the flat shape, and in this state, this is heated for a predetermined time in the next secondary vulcanization step. Then, the secondary vulcanization is completed.

FIG. 10 shows a method for investigating and identifying a gas leakage location of the gas pipe 52 embedded in the ground using the expansion plug 10.
As shown in the figure, while the air pipe 42 is fed out from the reel 68 placed on the ground surface 66, the expansion plug 10 is inserted into the gas pipe 52 in the axial direction and fed from the opening 70 of the gas pipe 52. By supplying pressurized air to the inside of the expansion pipe 12, the rubber expansion pipe 12 is expanded radially outward, the gas pipe 52 is sealed with the expansion plug 10, and the pipe line is shut off.

At this time, if there is no gas leaking part ahead of the sealing part of the gas pipe 52 by the expansion plug 10, there is no decrease in the hermetic test pressure, so that the pressure in the gas pipe 52 taken out and detected through the conducting pipe 36 is constant. Held in pressure.
Therefore, if the pressure taken out through the conducting tube 36 and the pressure detected by the pressure detector is maintained at the constant pressure, it is determined that there is no gas leaking portion in front of the sealed plug and no gas leaking occurs. .
Conversely, if the hermetic test pressure decreases, it can be determined that gas leakage has occurred at any location ahead of the sealed plug location.

Therefore, after removing the air from the expanded rubber expansion tube 12 and contracting it in the radial direction, the gas expansion tube 12 is further moved forward by a predetermined distance, and the rubber expansion tube 12 is expanded again by supplying pressurized air, After the gas pipe 52 is sealed, the pressure drop in the gas pipe 52 is detected again through the conducting pipe 36.
Also at this time, if the hermetic test pressure is lowered, it can be determined that the leak point is further forward.
Therefore, the same operation is further repeated to sequentially move the expansion plug 10 forward.
If the decrease in the hermetic test pressure disappears at a certain point, it can be determined that the gas leakage location is between the final sealing plug location and the previous sealing plug location.

  In this way, according to the present embodiment, it is possible to pinpoint and identify the gas leak location, and therefore, when repairing the gas leak location, it is only necessary to dig up the soil to the minimum extent, Can be repaired quickly and with a small amount of work.

By the way, as shown in FIG. 10, if the gas pipe 52 has a bent portion 52A or the like for gas drawing into the apartment house 72 or the like, the expansion plug 10 must be fed along the bent portion 52A. Don't be.
In this case, if the rubber expansion tube 12 has a straight tube shape, the expansion plug 10 cannot be fed well along such a bent portion 52A.
However, in this embodiment, since the rubber expansion tube 12 is previously flattened, that is, the shape after vulcanization is flattened, the expansion plug 10 is fed well along such a bent portion 52A. be able to.

11 and 12 specifically show this.
As shown in the figure, in this embodiment, the rubber expansion pipe 12 is fed forward in the gas pipe 52 while being held in a flat shape. At this time, it is preferable to suck the inside of the rubber expansion tube 12 through the air tube 42 under a negative pressure.
By doing in this way, the rubber expansion tube 12 can be flattened more favorably and held.

  The expansion plug 10 that has been sent forward in the gas pipe 52 in such a state has good flexibility when the rubber expansion tube 12 reaches the bent portion 52A based on its flat shape. Therefore, the rubber expansion tube 12 is generally bent and deformed along the bent portion 52A without being hindered from being advanced by the bent portion 52A, so that it can be further improved along the bent portion 52A. It is possible to enter towards (the previous).

For example, as shown in FIG. 10, when the gas leakage point P is located immediately before the bent portion 52A, it has been difficult to specify the gas leakage point in the past, but in this embodiment, the expansion plug 10 Can be sent further forward along the curved portion 52A, and the gas pipe 52 can be tightly plugged by expanding it again, so that the gas leakage point P can be correctly identified as described above. Is possible.
That is, after the expansion stopper 10 has entered along the bent portion 52A, the compressed air is sent to the air tube 42 that has been pulled to a negative pressure until now, and the rubber expansion tube 12 is expanded, thereby the bent portion. The gas pipe 52 can be sealed at the tip of 52A. If there is no decrease in the airtight test pressure in the gas pipe 52 on the front side of the hermetic plug location at that time, it can be determined that the gas leak location P exists immediately before that.

  As described above, in the present embodiment, the rubber expansion tube 12 is vulcanized into a flat shape in advance, and the expansion plug 10 is inserted into the gas pipe 52 with the inside thereof sucked with negative pressure. In this way, the rubber expansion pipe 12 can be made to have a better flat shape, and the insertability of the expansion plug 10 into the gas pipe 52, particularly the insertability along the bent portion 52A can be further improved. Can do.

FIG. 13 shows another embodiment of the expansion plug 10, in which a soft seal tube 74 is put on the outside of the rubber expansion tube 12 in an externally fitted state.
The seal tube 74 is provided with a pair of annular seal lips 76 spaced apart from each other in the axial direction, and the seal lip 76 is in close contact with the inner peripheral surface of the gas pipe 52, so that the gas pipe can be improved. 52 can be sealed.
Other configurations are basically the same as described above.

Although the embodiments of the present invention have been described in detail above, these are merely examples.
For example, the above example is an example in the case where the present invention is applied to a method for investigating and identifying a gas leak location of the gas pipe 52, but the present invention is simply for sealing the gas pipe 52 at a specific location and blocking the pipeline. It is also possible to use it only for the purpose.
In this case, the expansion plug 10 can be configured in a form in which the conducting tube 36 is omitted, and more specifically, the expansion plug 10 can be configured in a form in which a structure for taking out and detecting the pressure ahead of the sealed plug portion is omitted. .

  In addition, the present invention can be applied as a method for shutting off not only gas pipes but also water pipes and other pipes, and the present invention can be implemented in various modifications without departing from the spirit of the present invention. It is.

It is a figure which shows the expansion stopper used for one Embodiment of this invention in an external appearance state. It is a longitudinal cross-sectional view of the expansion stopper shown in FIG. It is a figure which decomposes | disassembles and shows the expansion | swelling stopper shown in FIG. FIG. 3 is a cross-sectional view of FIG. It is a figure which shows the state which sealed the piping with the expansion | swelling stopper of FIG. It is process explanatory drawing which shows an example of the manufacturing method of the rubber expansion pipe in the expansion stopper of FIG. It is process explanatory drawing following FIG. It is process explanatory drawing which shows the flattening method of the rubber expansion pipe different from FIG. 6 (II). FIG. 9 is a process explanatory diagram illustrating a method for flattening a rubber expansion pipe, which is further different from that of FIGS. It is explanatory drawing of the sealing plug method of piping of one Embodiment of this invention. It is explanatory drawing which shows the principal part in the embodiment in order of a process. It is explanatory drawing of the process following FIG. It is a figure which shows the other form example of an expansion stopper. It is principal part process explanatory drawing of the conventional repair method of the gas leak location in gas piping. It is a comparative example figure which shows the identification method of the gas leak location in gas piping. It is explanatory drawing of the malfunction when the thing which has a straight tubular and circular cross-section rubber expansion pipe is used as the expansion plug shown in FIG.

Explanation of symbols

10 Expansion plug 12 Rubber expansion pipe 36 Conducting pipe (inner pipe)
52 Gas piping 52A Bent part

Claims (4)

An expansion plug provided with a rubber expansion pipe as a main element is inserted into the pipe, and the rubber expansion pipe is radially expanded with a pressurized fluid supplied to the inside of the rubber expansion pipe so that the pipe is tightly plugged. A method of sealing a pipe to shut off
The vulcanized shape of the rubber expansion tube is made flat, and the expansion plug is inserted into the pipe while maintaining the flat shape, and then the pressurized fluid is supplied to the rubber expansion tube. A pipe sealing method characterized by inflating and sealing the pipe.   2. The pipe sealing method according to claim 1, wherein the pipe has a bent portion, and the expansion plug is inserted into the pipe along the bent portion to seal the plug.   3. The pipe sealing method according to claim 1, wherein the expansion plug is inserted into the pipe while the inside of the rubber expansion pipe is sucked with a negative pressure.   4. The expansion plug according to any one of claims 1 to 3, wherein the expansion plug forms a double tube of the rubber expansion tube and an inner tube inserted through the rubber expansion tube, and the inner tube is sealed by the expansion plug. A pipe sealing method characterized in that the pipe is configured as a conducting pipe for detecting the pressure in the pipe ahead.

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