JPH0132399B2 - - Google Patents

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is designed to ensure 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 they 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. 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 deterioration of sealing performance.

However, for existing gas pipes that have a medium diameter or small diameter, workers cannot enter the pipe and repair the inner surface of the pipe joint like they can for large diameter pipes, so it is difficult to carry out repair work. Therefore, 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.

[Problem to be solved by the invention]

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 towing cable and slides in airtight contact with the inner surface of the pipe, and this movement process When the pig passes through the pipe joint, in the first step, a low-viscosity resin penetrant is impregnated into the sealing material from between the joints under pressure.
In the second step, we developed a repair method that involves filling the space between the joints with a high-viscosity resin putty. According to this repair method, not only is it possible for an operator to repair the inner surface of the joint of a pipe while it is buried while the worker is outside, but also the sealing material dries and shrinks due to the penetrating agent that is impregnated under pressure into the sealing material. The sealing effect is enhanced by blocking the micropores, and the penetrating agent in the first stage acts as a lubricant for filling with the putty agent in the second stage. Even if the surface between the pipe joints is rough and uneven, the putty fills with good adhesion, and the double airtightness of the penetrating agent and the putty allows for highly effective repairs. However, the resin pressurizing means used to infiltrate or fill the pipe joint with resin is complicated.

The present invention is a repair device used to carry out the above-mentioned repair method, and when moving resin in a pipe through a pig, the required osmotic pressure and filling pressure can be maintained in the resin without applying external pressure to the pig. In addition, even if the amount of resin filling decreases as the repair progresses, there will be no void in the resin filling space, and in addition, the resin can reliably penetrate and fill the inside of the sealing material of the pipe joint. The object of the present invention is to provide a device for repairing a pipe joint of an existing pipe.

[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 front and rear pigs are provided with a means for moving the pigs, and the rear pig serves as a tow pig and extends a tow rope forward in the moving direction, and the front pig serves as a movable pig and is slidably inserted into the tow rope. When the rear pig is towed and moved, the front pig moves and applies the required filling pressure to the resin filled between both pigs. The escape groove that opens to the front and the resin filling groove that opens to the rear are shifted in position in the circumferential direction so that they do not communicate with each other, and the opposing ends of both grooves overlap in the direction of movement. It is characterized by being formed so as to.

[Effect]

With the above configuration, the resin between both pigs is compressed by the rear pig, and the front pig infiltrates and fills the pipe joint, so that even when the resin between both pigs decreases, the rear pig remains in the front position. Keep close to the pig and keep pressurizing it.

[Example] Hereinafter, an example of the present invention will be specifically described with reference to the drawings.

In the figure, reference numeral 1 indicates a rear pig serving as a towing pig, and reference numeral 2 indicates a front pig serving as a movable pig disposed in front of the pig 1 at a predetermined spacing.
Hereinafter, this rear side pig 1 will be referred to as a "traction pig", and the front side pig 2 will be referred to as a "movable pig". These towing pigs 1 and movable pigs 2 are cylindrical pigs with an outer diameter that corresponds to the inner diameter of the existing pipe 12 to be repaired and can slide in airtight contact with the inner surface of the existing pipe 12. On the outer periphery of the movable pig 2 on the front side, there are grooves 3 for resin filling that open toward the rear in the direction of movement, and grooves 4 for escaping substitutes that open toward the front in order to provide the functions described below. However, in the axial direction, the opposing ends overlap each other, and in the circumferential direction, the grooves 3 and 4 are formed at different positions so that they do not communicate with each other (see FIG. 6). In addition, tow ropes 5 and 6 that also serve as length measurements are connected to the rear tow pig 1 in the forward and rear directions of movement, and the tow rope 5 extending forward passes through the center of the movable pig 2. movable pig 2 against tow rope 5
is slidable. This movable pig 2 utilizes the resistance generated by sliding contact with the inner surface of the tube when moving inside the tube, to apply the required amount to the resin (penetrant A or putty agent B described later) interposed between the two pigs 1 and 2. This applies osmotic pressure and filling pressure.

The repair device having such a configuration is used in the following manner for repairing the inner surface of the existing pipe 12. The existing pipe 12 buried underground is a long cast iron pipe connected via pipe joints 13 and 14, such as water pipes, using a conventional piping method. In repairing the pipe joints 13 and 14 of the existing pipe 12, the present invention divides the existing pipe 12 into units of length suitable for repair, and repairs the plurality of pipe joints 13 and 14 interposed within that section. The pipe joint part 1
3, as is well known in the art, for example, a large diameter portion 13a provided at the end of one pipe is connected to the end 13 of the other pipe.
b are butted against each other, a sealing material 15 usually called "hemp skin" is filled in the butt-fitting part, and the opening is sealed with a lead material 16.

The towing pig 1 and the movable pig 2 are introduced into the existing pipe 12 to be repaired through one opening thereof, with the space in which the two pigs 1 and 2 face each other being filled with resin. Here, in the first stage, the resin is, for example, penetrant A, which is a low viscosity resin (100 cps to 1000 cps) with hardening properties such as epoxy resin, and in the second stage, a high viscosity resin (for example, 100,000 cps to 300,000 cps) is used as the resin.
cps) putty agent B is filled and moved inside the existing pipe 12 in the direction of the arrow X by being pulled by the towing rope 5. During this movement, pressurized air may be sent into the existing pipe 12 behind the towing pig 1, and the pig may be moved by a combination of the traction action by the rope 5 and the pneumatic action. In FIG. 2, 21 is a winch that winds up the towing rope 5, and 22 is a compressor that supplies pressurized air.

Now, to explain a construction example in detail, in the first stage, as shown in Figures 1 and 2, penetrant A is filled between the towing pig 1 and the movable pig 2 and the pig moves in the direction of the arrow X. be done. During this movement, the movable pig 2 generates movement resistance caused by sliding contact with the inner surface of the tube, so a backward pressing force acts on the penetrant A. On the other hand, the penetrant A is moved by the towing pig 1 By being pushed from the back to the front, the penetrant A
The required resin extrusion pressure is generated.

However, due to the movement within the pipe, the front movable pig 2 moves to the first position.
As shown in the figure, when the movable pig 2 is moved to the position of the pipe joint 13 (or 14), the resin filling groove 3 formed on the outer periphery of the movable pig 2 communicates with the pipe 19 between the pipe joints 13. A is pumped through the groove 3 to the pipe joint 13 and permeates into the sealing material 15 through the space 19 between the joints.

At this time, if there is an air leak in the pipe joint 13 (or 14), the penetrant A penetrates by pushing out the residual air in the sealing material 15.
In addition, if there is no air leakage, the residual air in the sealing material 15 will be trapped due to the pressurized penetration of the penetrant A, but in this case, the outer periphery of the movable pig 2 will be Opening groove 4
As shown in FIG. 3, the residual air in the sealing material 15 circulates in the pipe circumferential direction from the gap 19 due to the push-out action of the penetrating agent A under pressure, and passes through the groove 4 into the movable pig 2. Since the air escapes into the front space, the replacement effect between air and penetrant A is ensured, and penetrant A
is deeply penetrated into the entire area of the sealing material 15. During this infiltration, if the movement of the towing pig 1 is temporarily stopped or the speed is controlled to a low speed state, the infiltration action can be performed more reliably.

When the impregnating action of the penetrant A on one pipe joint part 13 (or 14) is finished, the towing pig 1,
The movable pig 2 is moved within the existing pipe 12 by being pulled by the aforementioned rope 5.

In this way, when the impregnating action of the penetrant A in the first stage is completed, in the second stage, the space facing the towing pig 1 and the movable pig 2 is filled with a high-viscosity resin putty B. When the movable pig 2 on the front side relative to the pipe joint 13 (or 14) moves to the position shown in Fig. 1 by moving it within the existing pipe 12 as described above, the movement is temporarily stopped or at a low speed. Fill the space 19 between the pipe joints with putty agent B.
In this case, a surplus of the previous penetrant A remains in the gap 19, but as shown in FIG. 4, the movable pig 2
A groove 4 formed on the outer periphery of the groove 4 communicates with the front space, and since filling pressure is applied to the putty agent B, the putty agent B is substituted and filled into the space 19 via the groove 3. .

In this construction method, the penetrating agent A that is impregnated under pressure in the first stage acts as a lubricant for the filling of the putty agent B in the second stage. Even if the surface between the pipe joint part 13 (or 14) is rough, the putty agent B has good adhesion, and the penetration agent A and the putty agent The double airtightness of B allows a highly effective repair to be achieved (see Figure 5).

In addition, during the above construction, if a branch pipe branches from the existing pipe 12, the tip side of this branch pipe is closed, or pressurized air is sent from the tip side to the branch pipe. It is possible to prevent the resin from entering.

〔Effect of the invention〕

Since the present invention has the above configuration, the following effects can be obtained.

(1) First, of a pair of pigs arranged in front and behind, the rear pig is used as a towing pig, and the front pig is used as a movable pig, and when the pigs are towed and moved, the sliding contact resistance that occurs on the front movable pig with the inner wall of the pipe Since the required extrusion pressure is generated in the resin filled between both pigs, the resin can be pressurized and infiltrated into the sealing material of the pipe joint in the pipe or between the joints.
When filling and sealing the resin, a special means for applying a predetermined filling pressure to the resin, such as a means for supplying pressurized air to the pig for resin filling, can be eliminated, and the apparatus can be simplified.

(2) Also, when moving resin into the pipe via the pig, if the groove on the outer circumference of the front movable pig matches the groove between the fittings at the position of the pipe joint, the resin will be transferred through the groove. However, the distance between the joints is automatically
Since the sealing material is infiltrated into the interior of the sealing material under pressure or filled and sealed in between, there are no mistakes in repairing the pipe joint, and the means for detecting the position of the pipe joint can be omitted.

(3) In addition, the pig has an escape function for air, etc. that stays inside or between the sealing material during resin penetration and filling, so the resin and air are effectively replaced and the resin penetrates and fills. Actions can be performed accurately.

(4) Furthermore, even if the amount of resin filling decreases as the repair progresses, the movable pig moves closer to the towing pig in response to the decrease, so there is no gap in the resin filling space, and the resin is constantly being filled. It is possible to pressure infiltrate the inside of the sealing material of the pipe joint part with the required osmotic pressure and filling pressure, or to fill and seal between the joint parts.

[Brief explanation of drawings]

FIG. 1 is a longitudinal sectional view partially cut away and showing one embodiment of the present invention, FIG. 2 is a perspective view showing the entire longitudinal section, FIGS. The figure is a perspective view of the pig. 1... Rear pig (traction pig), 2... Front pig (movable pig), 3, 4... Groove, 5, 6... Traction rope, 12... Existing pipe, 13, 14... Pipe joint Part, 13a...Large diameter part, 13b...Pipe end, 15
... Sealing material, 16 ... Lead material, 18 ... Sensor,
19... Between, A... Penetrant, B... Putty agent.

Claims (1)

[Claims] 1. A means for disposing at least a pair of front and rear pigs inside an existing pipe, which are pulled by a towing rope and sliding in airtight contact with the inner surface of the pipe, and filling resin between the pigs and moving the pigs. The pair of front and rear pigs has a towing rope extending forward in the direction of movement, with the rear pig serving as a towing pig;
The front pig is slidably inserted into the towing rope as a movable pig, so that when the rear pig is towed, the front pig moves to apply the required filling pressure to the resin filled between both pigs. In addition, on the outer periphery of the front pig, an escape groove whose end opens forward in the direction of movement and a resin filling groove whose end opens rearward are positioned in the circumferential direction so that they do not communicate with each other. 1. A pipe joint repair device for an existing pipe, characterized in that the opposite ends of both grooves overlap in the direction of movement.