JPH0160720B2 - - Google Patents

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a method for ensuring sealing performance from the inner surface of the pipe while the pipe joint part of an existing gas pipe, etc., is mainly buried underground. This invention relates to a pipe joint repair device for an existing pipe to be repaired.

[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 regenerate the pipes from corrosion and the like while the pipes are still buried. In particular, with existing gas pipes buried underground, where cast iron pipes are connected using water-type joints or G-type joints, the sealing performance of the pipe joints has deteriorated and there is a need for repair. .
In other words, recently, city gas has become dry natural gas instead of the coal gas that had been used for a long time, and in the case of conventional coal gas, the tar component in the gas is removed by Deterioration of sealing performance was not a particular problem because it penetrated into the sealing material called "hemp skin," but in the case of dry natural gas, the sealing material dries and shrinks, causing voids. Since the sealing performance deteriorates and causes gas leakage, it is necessary to ensure the sealing performance of the pipe joint.
Since then, it has become necessary to carry out repairs to prevent seal deterioration.

However, in the case of existing gas pipes with medium or small diameter pipes, it is not possible for workers to enter the pipe and repair the inner surface of the pipe joint, unlike in the case of large-diameter pipes. Construction is difficult, and there is a need for a construction method in which workers are outside to repair the inner surface of pipe joints while they are buried.

Regarding this construction method, the present inventor has provided a means for moving the resin into the existing pipe through a pig that is pulled by a tow rope and slides in airtight contact with the inner surface of the pipe, and this movement process When the pig passes through a pipe joint, in the first stage, a low-viscosity resin penetrant is infiltrated into the sealing material between the joints under pressure, and in the second stage, a high-viscosity resin penetrant is infiltrated between the joints. We have developed a repair method that uses resin putty.

[Problem to be solved by the invention]

According to this repair method, the worker is outside and
Not only is it possible to repair the inner surface of a pipe joint while it is buried, but the penetrating agent impregnated into the sealing material under pressure closes the micropores caused by drying and shrinkage of the sealing material, increasing the sealing effect. Moreover, since the penetrating agent into the gap performed in the first stage acts as a lubricant for the filling of the putty agent in the second stage,
Between the pipe joints Even if the surface is rough and uneven, the putty fills with good adhesion, and the double airtightness of the penetrant and putty makes for highly effective repairs. However, the pig was designed to fill the resin once at a time, and there was a problem in that it was not always possible to do enough work in one go.

The present invention is a repair device used to carry out the above-mentioned repair method, and when the resin is moved within the pipe via the pig, the resin reliably penetrates into the sealing material of the pipe joint and flows between the pipe joints. The purpose of the present invention is to provide a pipe joint repair device for an existing pipe that is devised so that the resin filling work can be performed by passing the front and rear pigs, respectively, so that the putty filling can be performed reliably.

[Means to solve the problem]

In order to achieve this object, the present invention provides at least a pair of front and rear pigs inside an existing pipe that is pulled by a towing rope and slides in airtight contact with the inner surface of the pipe, and fills resin between the pigs. , the filling pressure is applied at least to the pipe joint part, and both of the above pigs have a
The grooves whose ends open forward in the direction of movement and the grooves whose ends open rearward are shifted in phase so that they do not communicate with each other in the circumferential direction, and the opposing ends of both grooves are arranged in the direction of movement. The pigs are formed so as to overlap each other, and are connected by a compression spring that acts in a direction in which the two pigs approach each other.

[Effect]

With the above configuration, the pig on the front side of the pipe joint part allows the substituted material in the pipe joint part space to escape forward,
In addition, in the rear pig, the substituted material escapes backward and the resin is infiltrated or filled.

〔Example〕

Hereinafter, one embodiment of the present invention will be specifically described with reference to FIGS. 1 to 8.

In the figure, reference numeral 1 indicates a rear pig serving as a towing pig, which is pulled forward by a towing rope 2. Further, the front pig 3 through which the tow rope 2 is fluid-tightly and slidably inserted is a movable pig, and its relative distance to the rear pig 1 can be varied, and as will be described later, both pigs 1 and A resin such as a penetrant or a putty agent is filled between the three spaces. These pigs 1 and 3 are cylindrical in shape and have an outer diameter that corresponds to the inner diameter of the existing pipe A to be repaired so that they can slide in airtight contact with the inner surface of the existing pipe A. Pigs 1 and 3 are provided with grooves 4a and 4 that open toward the rear in the direction of movement, with the intention of providing functions to be described later.
a' and grooves 4b, 4b' that open toward the front in the moving direction are provided on its outer periphery. Said grooves 4a' and 4
b is a groove for resin filling, the grooves 4b' and 4a are grooves for escape of substituted substances, and each groove 4a is a groove for resin filling.
and 4b and 4a' and 4b' are in such a relationship that their opposing ends overlap in the axial direction, and both grooves 4a and 4b and 4a' and 4b' do not pass through each other in the circumferential direction. They are formed in different positions (see Figure 2).

A compression coil spring 5 is interposed between the pigs 1 and 3 to adjust the filling pressure, and a tow rope 6 is connected to the rear of the pig 1, which also serves as a length measurement. A block 8 having a magnetic sensor 7 is attached to the front side of the pig 3 at a predetermined distance.
A plurality of are installed around the block 8 in an evenly spaced arrangement.

When the pig 3 moves inside the pipe, the pigs 1 and 3
The required osmotic pressure and filling pressure are applied to the resin (penetrating agent X or putty agent Y, which will be described later) interposed between the two.

The repair device having such a configuration is used for repairing the inner surface of the existing pipe A in the following manner. The existing pipe A buried underground here is a long cast iron pipe connected via water pipe joints B and C using a conventional piping method. When repairing the pipe fittings B and C of the existing pipe A, the present invention divides the existing pipe A into units of length suitable for repair, and repairs the plurality of pipe joints B and C interposed within that section. As is conventionally known, the pipe joint part B is, for example, a large-diameter pipe provided at the pipe end of one pipe.
B ₁ and the other tube end B ₂ are brought into contact with each other, and the butt fitting part is filled with sealing material D, which is usually called "hemp skin", and the opening is sealed with lead material E. The connection structure is as follows.

The pigs 1 and 3 are introduced into the existing pipe A to be repaired from one of the openings thereof, with the space in which the pigs 1 and 3 face each other being filled with resin. In the first stage, the resin filled here is, for example,
A penetrant X made of a low viscosity resin (100 cps to 1000 cps) with hardening properties such as an epoxy resin is filled, and a putty agent Y made of a high viscosity resin (e.g. 10,000 cps to 300,000 cps) is filled in the second stage. It is moved inside the existing pipe A by being pulled by the towing rope 2. Upon this move,
Pressurized air may be sent into the existing pipe A behind the pig 1, and the pig may be moved by a combination of the traction action by the rope 2 and the pneumatic action. Reference numeral 9 in FIG. 2 is a winch that winds up the tow rope 2.

Now, to explain the construction example specifically, the first
At this stage, as shown in FIG. 2, penetrant X is filled between pigs 1 and 3 and moved in the direction of the arrow.
During this movement, the front pig 3 generates movement resistance due to sliding contact with the inner surface of the tube, so the penetrant X
On the other hand, as the rear pig 1 is pulled from the rear to the front by the tow rope 2, the penetrant arise.

When the magnetic sensor 7 detects the position of the pipe joint part B (or C) due to the movement within the pipe, it can be seen that the pig 3 will then reach the pipe joint part B (or C) by moving a predetermined distance. At this point, the pulling of the towing rope 2 is stopped or the speed is reduced. When the front pig 3 moves to the position of the pipe joint part B ₍ or C) as shown in FIG. Since the penetrating agent X is forced into the pipe joint part B through the groove 4a', it is permeated into the sealing material through the joint part _B3 .

At this time, if there is an air leak in the pipe joint B (or C), the penetrant X will penetrate by pushing out the residual air in the sealing material D, and
If there is no air leakage, the residual air in the sealing material D will be trapped due to the pressurized penetration of the penetrant There is a groove 4b′ that
As shown in Figure 4, the residual air in the sealing material D is removed by the pushing action of the penetrating agent
Pig 3 goes around from B ₃ in the pipe circumferential direction and passes through groove 4b'.
Since the penetrating agent X escapes into the space in front of the sealing material D, the substitution effect between the air and the penetrating agent X is reliably performed, and the penetrating agent X is deeply penetrated into the entire area of the sealing material D. During this penetration, if the movement of the pig 1 is temporarily stopped or the speed is controlled to a low speed state, the action of the compression coil spring 5 causes the pig 3 to approach the pig 1 side and pressurize the penetrant X, causing it to slowly penetrate into the sealing material D. This allows the penetration work to be carried out more reliably.

Moreover, when the pig 1 passes through the pipe joint part B (or C), conversely, from the front of the pig 1, the groove 4b
If the penetrant is filled again between the pipe joint B ₃ through the pipe joint B 3 and there is displacement air, this will be replaced by the groove 4a.
is emitted backwards through the As a result, penetrant filling is performed twice during the passage of the pair of pigs 1 and 3.

When the impregnating action of the penetrating agent X on one pipe joint part B (or C) is completed, the pigs 1 and 3 are again moved within the existing pipe A by being pulled by the rope 2 described above.

Through this process, the penetrant X is filled into the sealing material D for each pipe joint, but during this time, the amount of residual penetrant They are approached by the action of resistance and compression coil springs 5.

In this way, after the penetrating action of the penetrant A in the first stage is completed, in the second stage, as shown in FIGS. After filling Y and moving it within the existing pipe A as described above, and confirming the position by detection by the magnetic sensor 7, move it to the pipe joint B (or C).
When the pigs 1 and 3 move to the relative positions shown in Fig. 6, the movement is temporarily stopped or at a low speed, the pig 1 is pulled by the towing rope 2, and pressurized air is added to the space behind it. and apply filling pressure to the putty agent Y. In this case, between B ₃ and the previous penetrant X
However, since the suction force is applied from the front of the pig 3 through the groove 4a' and the filling pressure is applied through the groove 4a', this is pulled out and replaced. Filled with putty agent Y, substitution can be achieved.

Furthermore, the pipe joint part B is pulled by the towing rope 2.
(or C), when the pig 1 corresponds to the groove 4b
With the putty agent Y applying the filling pressure to the gap _B3 , the groove 4a corresponds to the gap _B3 ,
Replacement with penetrant X is achieved again, and a second replacement and filling is performed.

In addition, in this construction method, the penetrating agent Even if this happens, resin filling can be achieved reliably, and since the replacement and filling are performed twice, sufficient resin filling can be achieved. In addition, even if the surface between the pipe joints is rough and uneven, the adhesion of the putty agent Y is good, and the dual airtightness of the penetrant X and putty agent Y allows for repairs with a high sealing effect. Ru.

As shown in FIG. 8, the pig 3 is also provided with a towing rope 10 extending rearward, and by passing through the pig 1 and extending backward, the towing rope 10
It is also possible to increase the filling pressure between both pigs 1 and 3 by pulling 0.

In the above embodiment, the filling pressure was increased by utilizing the traction action of the traction rope 2 and the sliding friction of the pig 3 against the inner wall of the existing pipe A, but other means were used to increase the filling pressure. Of course, the filling pressure may be increased.

〔Effect of the invention〕

As described above in detail, the present invention achieves the replacement of the resin with the air in the pipe joint section or the putty agent through the grooves of both the pigs, and this also occurs twice in each of the front and rear pigs. This can be achieved over many times, and the resin penetration and filling action can be performed accurately. Furthermore, as the repair progresses, even if the resin between the pigs decreases, the distance between the pigs can be made closer to accommodate the decrease. Pressurized infiltration into the joints or resin filling between the joints can be performed.

[Brief explanation of drawings]

FIG. 1 is a vertical sectional side view showing an embodiment of the present invention;
Fig. 2 is a perspective view showing the structure of the pig and how it is used; Figs. 3 to 5 are partially enlarged vertical sectional views showing the state of penetrant filling; Figs. 6 and 7 are putty agent filling. FIG. 8 is a partially enlarged longitudinal sectional view showing the situation, and FIG. 8 is a longitudinal sectional side view showing another embodiment. 1... Rear side pig, 2... Tow rope, 3... Front side pig, 4a, 4a', 4b, 4b'... Groove, 5...
...Compression coil spring, 6...Tow rope, 7
...Magnetic sensor, 8...Block, 9...Winch, 10...Tow rope.

Claims (1)

[Scope of Claims] 1. At least a pair of front and rear pigs that are pulled by a towing rope and slide in airtight contact with the inner surface of the pipe are provided in the pipe of an existing pipe, and a resin is filled between the pigs so that at least the pipe Filling pressure is applied at the joint, and both of the above pigs have grooves on their respective outer peripheries, one with a groove opening toward the front in the direction of movement, and the other with a groove opening toward the rear in the direction of movement. The phases of the two grooves are shifted so that they do not communicate with each other in the direction of movement, and the opposing ends of both grooves are formed to overlap in the direction of movement, and the two pigs are connected by a compression spring that acts in the direction of approaching each other. A pipe joint repair device for existing pipes, which is characterized by: 2 Among the pigs, the rear pig is towed forward by a towing rope, and the front pig is a movable pig that is liquid-tight with respect to the towing rope and can freely move back and forth. Pipe joint repair device for existing pipes as described. 3. Each of the pigs is constructed such that the front pig is towed by the rear tow rope and the rear pig is towed by the front tow rope, and is relatively movable. Or the pipe joint repair device for an existing pipe as described in item 2.