JPH0356357B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention repairs a pipe joint of an existing pipe that is underground, etc., so as to ensure sealing performance from the inner surface of the pipe while it is buried. This invention relates to a pipe joint repair device for existing pipes.

[Conventional technology]

In recent years, various methods have been proposed for repairing existing pipes such as gas pipes, water pipes, etc. buried underground from the inside so as to rehabilitate the pipes from corrosion while remaining buried. In particular, in existing gas pipes in which cast iron pipes are socket-joined with water-type joints or G-type joints, the linen skin that acts as a sealing material in the pipe joints weathers and the sealing performance deteriorates. In addition, the connection state of pipe joints changes due to the load of vehicles passing on the road, earthquakes, etc., which can cause leaks, so there is a need for repairs for the purpose of leak repair or preventive maintenance.

Conventionally, in order to repair this pipe joint, a pig is used to move resin along the inside of the pipe, as seen in, for example, Japanese Patent Application Laid-open No. 59-40088. Repairs such as filling are being carried out.

The above-mentioned repair pig has a replacement function that allows the resin to be replaced with air and filled while discharging the air accumulated between the joints. Conventionally, for example, the prior art described in Japanese Patent Publication No. 58-53584 has been known to have a groove formed therein.

The present applicant previously proposed a device as shown in FIG. 1 as a pipe joint repair device using the above-mentioned replacement pig. That is, two first and second pigs 1 and 2, front and rear, are inserted into the existing pipe A, a resin is interposed between the two pigs, and the first pig 1 is penetrated and connected to the second pig 2. By pulling the pulling rope 3, pressure (filling pressure) is applied to the resin and the resin is moved inside the pipe. A filling groove 5 is provided so that the first filling groove 5 is
When the pig 1 corresponds to the position of the pipe joint part B, while discharging the air stagnant between the pipe joint part B through the replacement groove 4, the air is discharged from the filling groove 5 between both pigs 1 and 2 The resin present in the pipe joint part B is replaced and filled into the space between the pipe joint parts B.

[Problem to be solved by the invention]

However, when repairing the seal of a pipe joint using the apparatus shown in FIG. 1, the following problem occurred.

In other words, the frictional resistance R against the inner wall surface of the pipe when the first pig 1 moves inside the pipe depends on the state of rust generated on the inner wall of the pipe, the state of accumulation of tar and other chemical substances contained in the gas, and the branching of branch pipes. It varies depending on the position of the protrusion into the pipe, the error in the inner diameter of the pipe itself, etc.

This change in frictional resistance R affects the pressure (filling pressure) on the resin interposed between both pigs, and if the filling pressure fluctuates significantly, the resin will be affected when it passes through the branch position of the branch pipe branching from the existing pipe. This changes the penetration depth and amount of the resin that enters the branch pipe, leading to a closed state of the branch pipe and making it difficult to perform post-treatment to remove the resin that has entered.

In addition, air pressure is applied to the branch pipe from the outside in order to prevent resin from entering the branch pipe or to eliminate the intruding resin. When the air pressure is increased, another problem arises in that if a branch pipe has a corroded part, the corroded part will be further damaged.

The present invention was proposed in view of the above-mentioned problems, and the circumferential surface of the first pig can be deformed to adapt to the condition of the inner wall surface of the pipe when moving inside the pipe, thereby reducing fluctuations in frictional resistance that occur in the resin. It is an object of the present invention to provide a pipe joint repair device for an existing pipe that prevents the filling pressure from increasing beyond a certain level.

[Means to solve the problem]

In order to achieve this objective, the present invention introduces a first pig and a second pig into an existing pipe to be repaired with a required amount of resin interposed between the two pigs, and the first pig has its outer periphery. A replacement groove communicating to the front and a filling groove communicating to the rear are provided in the part, and when the second pig is towed toward the first pig and the first pig corresponds to the position of the pipe joint part, In the device that replaces the resin with air and fills the space between the joint parts through the replacement groove and the filling groove, the first pig is made of an elastic material with a hollow interior. , and is characterized by forming an opening through which resin flows into the hollow space.

[Effect]

In the first pig with such a configuration, the circumferential wall of the pig can be deformed to adapt to the condition of the inner wall of the pipe, so when moving inside the pipe, the frictional resistance against the inner wall of the pipe can be reduced, and the effect on the resin can be reduced. The filling pressure can be kept constant.

Furthermore, as the resin flows into the hollow part of the first pig, the filling pressure acting on the resin acts on the circumferential wall of the pig, and the contact pressure of the circumferential surface of the pig against the inner wall of the pipe can be maintained in a liquid-tight state. .

As a result, even when passing through a branch of a branch pipe branched from an existing pipe, the intrusion of resin into the branch pipe is reduced, and resin intrusion can be prevented simply by applying a slight air pressure to the branch pipe. Measures to prevent resin from entering and removing the branch pipes can be simplified and work efficiency can be improved.

〔Example〕

An embodiment of the present invention will be described below with reference to FIGS. 2 to 5.

In FIGS. 2 to 5, reference numeral 11 indicates the first
The first pig 11 has a cylindrical shape with a U-shaped cross section with a closed front end, a hollow interior, and an open rear end. The material is made of a soft sponge-like resin material and has elasticity. Further, on the outer periphery of the first pig, replacement grooves 12 and filling grooves 13 are arranged alternately at equal intervals in the circumferential direction. The above-mentioned replacement groove 12 is
Passage 14 (e.g. pipe) passing through the pig
It has a communicating opening to the front end of the pig through. Further, the filling groove 13 is connected to the internal hollow part 16 through the communication hole 15.
is connected to. A towing rope 17 is slidably inserted through the center of the pig 11, and a second pig 18 is connected to the rear end of the towing rope 17. This second pig 18 is also made of the same material as the first pig 11, and has a solid cylindrical shape.

Next, the repair situation of the existing pipe A using the first pig 11 and the second pig 18 described above will be explained.

The existing pipe A buried underground is a long cast iron pipe connected via a pipe joint B such as a water pipe type using a conventional piping system. When repairing the pipe joint B of the existing pipe A, we will divide the existing pipe A into units of length suitable for repair, and repair the multiple pipe joints B intervening within that section. As is conventionally known, in the joint part B, a large-diameter socket _B1 provided at one pipe end abuts an insertion port _B2 at the other pipe end, and the butt-fitting part is usually It has a connection structure in which a sealing material C called "hemp skin" is filled and the opening is sealed with a lead material D.

The first pig 11 and the second pig 18 are inserted into the existing pipe A to be repaired from one opening thereof,
A required amount of resin is filled between both pigs 11 and 18 and introduced. In the first step, the resin has a penetrating agent
In the process, high viscosity resin (e.g. 10,000 cps to 300,000 cps)
cps) putty agent Y is filled, and the tow rope 17
is moved inside the existing pipe A in the direction of the arrow. During this movement, it is preferable that negative suction pressure be applied to the front of the pig 11. As the second pig 18 is pulled forward by the pulling of the rope 17, the filled resin (X or Y) is subjected to compressive force between the pigs 11 and 18, increasing the internal pressure. The first pig 11 is pushed forward by this internal pressure.

To specifically explain a construction example, in the first step, a penetrant X is applied between the first pig 11 and the second pig 18.
When the first pig 11 reaches a position corresponding to the position of the pipe fitting part B during movement in the pipe, the liquid is filled into the internal space of the pipe fitting part B and the sealing material C through the displacement groove 12. Stagnant air is exhausted,
The penetrating agent X is replaced and filled there from the filling groove 13. This situation is illustrated in FIG. In short, in the pipe joint part B, the distance between the joint parts in the circumferential direction is
Since these are in communication, air and resin are exchanged through the space between them, and the sealing material C is impregnated with the penetrant X.

After a series of filling operations have been performed on several pipe joints B, next, as a second step, the pigs 11, 1
8 is filled with putty agent Y, and the existing pipe A is filled in the same way as above.
be introduced within. Then, in the pipe joint part B, the surplus of the penetrant X is discharged from the replacement groove 12, and the space between the pipe joint part B is filled with putty agent Y through the filling groove 13.

In this way, during the movement of the first pig 11 and the second pig 18, the pipe joint part B is replaced and filled with resin, but inside the existing pipe A, for example, as shown in FIG. A deposit T of tar and the like forms a resistance to passage of the first pig 11.

In this case, since the first pig 11 according to the present invention is made of an elastic material with the inside of the main body formed in the hollow part 16, the peripheral wall part can be easily deformed to adapt to the deposited part T, and The resistance for does not vary significantly. Moreover, the rear end of the first pig 11 is opened, and the resin interposed between the first pig 11 and the second pig 18 flows into the hollow part 16, and the filling pressure acting on the resin when moving in the pipe is reduced. Since it acts on the peripheral wall of the pig 11, the pig 11
The contact pressure on the circumferential surface of the tube is maintained sufficiently to maintain its liquid-tightness, and the tube moves in sliding contact with the tube.

〔Effect of the invention〕

As described in detail above, the present invention provides the first pig 11
Since we have devised the shape of the first pig 11 and the second pig 18, when passing the filling resin between the first pig 11 and the second pig 18 through the existing pipe, the resistance applied to the first pig 11 can be alleviated. The applied filling pressure can be kept stable. Moreover, the filling pressure acting on the resin acts on the circumferential surface of the first pig 11, causing the pig 1
Since the contact pressure between the peripheral wall 1 and the inner wall surface of the pipe can be maintained at a required level, leakage of the resin can be avoided.

As a result, even when passing through a branch of a branch pipe branched from an existing pipe, the intrusion of resin into the branch pipe can be reduced, or the intrusion of resin can be prevented simply by applying a slight air pressure to the branch pipe. This simplifies measures to prevent resin from entering and removing the branch pipes, and improves work efficiency.

[Brief explanation of drawings]

Fig. 1 is a longitudinal side view showing how the previously proposed repair device is used, Fig. 2 is an enlarged perspective view of the first pig showing an embodiment of the present invention, and Fig. 3 is a longitudinal side view showing the same use form. 4 and 5 are enlarged longitudinal sectional side views showing various aspects of the construction state. 11...First pig, 12...Replacement groove, 13...
... Filling groove, 14 ... Passage, 15 ... Communication hole, 1
6... Internal hollow part, 17... Traction rope, 18...
...Second pig, A...Existing pipe, B...Pipe joint part,
B ₁ ... socket, B ₂ ... insertion port, C ... sealing material,
D...Lead material, X...Penetrant, Y...Putty agent.

Claims (1)

[Claims] 1. A first pig and a second pig are installed in the existing pipe to be repaired.
A pig is introduced with a required amount of resin interposed between both pigs, and the first pig has a replacement groove communicating to the front and a filling groove communicating to the rear on its outer periphery, Tow the second pig to the first pig side and
When the pig corresponds to the position of the pipe joint part, the resin is replaced with air and filled into the space between the joint parts via the replacement groove and the filling groove, wherein the first pig is inside the main body. 1. A pipe joint repair device for an existing pipe, characterized in that the pipe joint is made of a hollow elastic material and has an opening through which resin flows into the hollow.