JPH0335557B2 - - Google Patents

Description

[Detailed description of the invention]

[Industrial Application Field] The present invention is directed to repairing existing pipes such as gas pipes installed underground so as to ensure sealing performance from the inner surface of the pipe while the pipe joints are still buried. This invention relates to a pipe joint repair device.

[Prior art]

In existing pipes such as gas pipes that are connected underground (under roads) by connecting long cast iron pipes with water-type pipe joints, the joints of the pipe joints are susceptible to the load of vehicles passing over the pipes, earthquakes, etc. Alternatively, due to aging, the joint condition may change and gaps may appear in the joint, or the sealing material in the joint may deteriorate, causing leaks. , it has been considered to repair the pipe joints of existing pipes from the inside of the pipe while leaving them buried. As a type of this repair method, a pig that slides in airtight contact with the inner surface of the pipe is inserted into the pipe of an existing pipe installed underground, with resin placed on the front side of the pig, and the pig is attached with a tow cable. A pipe joint repair method has been proposed in which resin is sequentially filled between a plurality of pipe joints interposed in an existing pipe while the pipe is being towed and moved inside the pipe. During this repair work, if a leak phenomenon occurs at the pipe joint, the resin will penetrate from between the joints into the sealing material, pushing out the air stagnant in the sealing material. Although the filling of the resin into the joint is reliably achieved, in the pipe joint where no leakage has occurred, the filling action of the resin causes a phenomenon in which stagnant air is trapped in the sealing material. There is a problem in that resin penetration is inhibited and resin filling becomes uncertain. In order to solve this problem, the present applicant previously proposed a pig for repairing pipe joints (replacement pig) that has the function of replacing air and resin, as described in Japanese Patent Application Laid-open No. 151692/1982. . The replacement pig according to this proposal has a resin filling groove whose end opens toward the front (resin side) in the direction of movement, and a replacement groove whose end opens toward the rear, on the outer circumferential body of the bullet-shaped pig body. The two grooves are shifted in phase in the circumferential direction so that their grooves do not communicate with each other, and the inner ends of both grooves overlap each other in the moving direction, so that the pig can adjust the position of the pipe joint. When passing through, the resin is introduced into the space between the pipe joints through the resin filling groove, and the introduction pressure of the resin removes air, etc. that remains between the pipe joints and the sealing material. By discharging the replacement material to the rear of the pig through the replacement groove, the resin is reliably contained in the sealing material of the joint, regardless of whether there is a leakage phenomenon at the pipe joint or not. It is configured to be infiltrated and filled.

[Technical problem of the invention]

By the way, when repairing existing piping using a replacement pig with the above-mentioned configuration, when filling the pipe joint with resin, the resin along with the replacement air escapes to the rear of the pig through the replacement groove. However, there is a problem in that this escaped resin is deposited inside the tube and causes a phenomenon of tube blockage. Because of this problem, conventional repair equipment connects another leveling pig behind the replacement pig to level the above-mentioned escaped resin on the inner surface of the pipe. Not only does this involve an increase in traction resistance due to the following traction, but there are also problems such as poor workability due to the large number of pigs.

OBJECTS OF THE INVENTION When repairing a pipe joint using the above-mentioned displacement pig, the present invention is designed to eliminate the need for conventional equipment when processing the resin that escapes to the rear of the pig through the above-mentioned displacement groove. This eliminates the need for leveling pigs, and the resin can be used to form a lining layer on the inner surface of the pipe at the joint, further improving the sealing effect of the joint. It is an object of the present invention to provide a pipe joint repair device for existing piping that is improved as much as possible.

[Structure of the invention]

For this purpose, the present invention provides an annular recess on the outer periphery of the rear part of the pig by forming a small diameter part with a smaller outer diameter in the rear part of the replacement pig body, and inserts the rear end of the replacement groove into the annular recess. At the same time, the outer diameter of the pig at the rear of the annular groove is formed to have a dimension that has a predetermined lining distance between it and the inner surface of the pipe, so that the replacement groove can be used when filling the pipe fitting with resin. The resin that escapes backward through the pipe is collected in the annular recess, and this resin can be used to form a lining layer on the inner surface of the pipe at the pipe joint. .

【Example】

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings. FIG. 1 is a diagram schematically showing the entire repair construction apparatus, and reference numeral 1 in the figure indicates an existing pipe to be repaired. This is a long pipe laid underground (under the road) by sequentially connecting cast iron pipes of a predetermined size using a conventional piping method using water-type pipe joints 13, and the pipe joints 13 are Generally, as shown in FIGS. 3 and 4, the large-diameter portion 13a provided at the end of one tube abuts the other end 13b, and the abutted fitting portion is usually It has a structure in which a sealing material 14 called "" is filled and the opening is sealed with a lead material 15. In the existing piping 1 connected and piped using the pipe joint part 13 having such a structure, the joint state changes due to the reasons stated at the beginning of the "Prior Art" section, and gaps may occur at the joint part. Also, the sealing material 14 deteriorates,
Since this causes a leak phenomenon, the present invention repairs the pipe joint 13 of the existing pipe 1 from the inner surface of the pipe while it is still installed for the purpose of repairing the leak or preventive maintenance. During this repair work, the existing piping 1 is divided into repair sections L of a length suitable for repair, for example, 100 m, and both separated ends 11 and 12 are exposed in vertical holes A and B opened above the ground. , an insertion guide tube 5 is connected to one separation end 11, and an outlet guide tube 6 is connected to the other separation end 12. The insertion guide tube 5 is provided with a resin injection port 5a having an opening/closing socket 52 and an air vent 5b having an opening/closing socket 53, and the resin injection opening 5a has a hose 7a. It communicates with the resin supply tank 7 through the resin supply tank 7, and from the resin supply tank 7, repair resins C and D, which will be described later, are injected into the pipe under filling pressure from a small compressor 7c driven by a generator 7b. . The other outlet guide pipe 6 includes a resin discharge port 6a for discharging residual resin and a pressure air supply port 6a.
b is provided, and this pressure air supply port 6b
is connected to the compressor 10 via the pressure operation unit 10a, and allows a predetermined amount of pressurized air to be introduced into the existing piping 1 from the supply port 6b. A tow cable 4 is introduced into the existing pipe 1 from the opening at the tip of the insertion guide pipe 5, and this tow cable 4
into the existing pipe 1 and connect it to the other outlet guide pipe 6.
By pulling the top pig 2 and the replacement pig 3, which are attached to the tow rope 4, into the tube through the insertion guide tube 5, the top pig 2 and the replacement pig 3 are introduced into the tube through the insertion guide tube 5. When introducing this, the first pig 2
Low clay resin C is injected into the front side of the resin injection port 5a, and joint sealing resin D is injected into the front of the replacement pig 3 on the rear side, and by winding up the tow rope 4, Lead pig 2 and replacement pig 3 are
While pushing the resins C and D injected into the front side, they are pulled and moved inside the tube from the inlet side to the outlet side. The leading pig 2 has a structure in which a plurality of fin pieces 22 are protruded from the body part 21 of the pig body in the shape of a cannonball, and this allows the low-viscosity resin C injected into the front side to be guided along the inside of the pipe. It performs the function of pushing and moving. Here, the low-viscosity resin C removes dust scattered inside the pipe of the existing pipe 1 and dust in the space of the pipe joint part 13 by adhering to it with the adhesiveness of the resin itself, thereby cleaning the inside of the pipe. At the same time, the resin D and the replacement pig 3 at the rear are
This provides a lubricating effect to facilitate the passage of traffic. On the other hand, the replacement pig 3 pushes the resin D injected into the front side along the inside of the pipe, and during this moving process, the replacement pig 3 pushes the resin D into the pipe of the pipe joint part 13 interposed in the middle of the existing pipe 1. In order to accomplish this function, the displacement pig 3 has a bullet shape that slides in airtight contact with the inner surface of the tube, as shown in the enlarged perspective view of Fig. 3. A resin filling groove 32 that communicates with the front side in the direction of movement and a replacement groove 33 that communicates with the rear side are formed in the body portion 31 of the pig body.
These resin filling grooves 32 and replacement grooves 33
The resin filling grooves 32 are formed at the left and right circumferential walls of the body 31, and the replacement grooves 33 are formed at different positions on the upper and lower circumferential walls of the body 31 so that the grooves do not communicate with each other. There is also a double concave groove 32,
33 are formed such that their inner end portions overlap each other in the moving direction (the axial direction of the body portion 31). Further, in the replacement pig 3, a small diameter part with a narrowed outer diameter is formed at the rear part of the body part 31, and an annular recess 34 is formed on the rear outer periphery of the pig body. A rear opening of the groove 33 is communicated with through a passage 35 formed in the body 31 . Further, the rear end portion 36 of the pig body that protrudes rearward from the annular recess 34 has an outer diameter l smaller than the inner diameter H of the existing pipe 1, and has a predetermined lining distance between it and the inner surface of the pipe. 〓.

[Explanation of action]

In such a configuration, when the pigs 2 and 3 are pulled by the pulling operation of the tow rope 4, the low viscosity resin C is pushed by the leading pig 2, and the inside of the existing pipe 1 is cleaned as described above. In addition, the lubricity of the inner surface of the tube is improved, which facilitates the passage of the resin D and the displacement pig 3. When the replacement pig 3 at the rear passes the position of the pipe joint part 13 due to the movement of the pigs 2 and 3, the resin D on the front side of the replacement pig 3 comes into contact with the inner wall of the existing pipe 1 during the towing movement. A predetermined resin pressure is generated on the rear side of the resin D due to the viscous resistance generated between the joints, and this resin pressure causes the resin D to flow from between the joint parts to the sealing material 14 through the resin filling groove 32. (See Figure 4). On the other hand, the air remaining in the joint space of the pipe joint part 13 and the sealing material 14 is naturally pushed out to the rear of the pig 3 through the displacement groove 33 by receiving the above-mentioned filling pressure, and due to this displacement action. , resin D is sealing material 1
The resin penetrates into the resin 4 sufficiently, and the pipe joint part 13 is reliably filled with the resin. When this pipe fitting portion 13 is filled with resin, a phenomenon occurs in which the resin escapes backward through the replacement groove 33 together with the replacement air.
The liquid enters the annular recess 34 through the annular recess 34 and is retained there. The resin that stays in the annular recess 34 due to the movement of the pig 3 is caused by the fact that the outer diameter of the rear end 36 of the pig is small and a gap between the linings is formed between it and the inner surface of the tube. The escaping resin forms a lining layer a on the inner surface of the pipe at the pipe joint 13.

【Effect of the invention】

As is clear from the above description, the present invention provides a small diameter part with a narrow outer diameter at the rear part of the replacement pig to provide an annular recess on the rear outer periphery of the pig, and a replacement groove is provided in the annular recess. In addition to making the rear open part open and communicating, the outer diameter of the pig behind the annular groove is formed to a dimension that has a predetermined lining distance between it and the inner surface of the pipe. The resin that escapes backward through the groove is stored in the annular recess, and this escaped resin is used to form a lining layer on the inner surface of the pipe at the pipe joint. Therefore, there is no need to follow and tow the leveling pig behind the replacement pig as seen in conventional repair equipment, and since the leveling pig can be omitted, the traction resistance of the pig and resin can be reduced. In addition, a lining layer made of escaped resin is formed on the inner surface of the pipe at the pipe joint, so the formation of this lining layer also further improves the sealing effect of the pipe joint, allowing repair of the pipe joint. The effect can be increased.

[Brief explanation of drawings]

Fig. 1 is a schematic diagram of the entire construction device showing one embodiment of the present invention, Figs. 2 a and b are longitudinal cross-sectional side views showing the pig in a towed state, Fig. 3 is an enlarged perspective view of the replacement pig, and Fig. 4 FIG. 2 is an explanatory diagram showing a state of replacing and filling resin into a pipe joint part. 1... Existing piping, 11, 12... Separation end, 13
...Pipe joint part, 13a...Large diameter part, 13b...
Pipe end, 14...Sealing material, 15...Lead material, 2...
Top pig, 21...body, 22...fin piece, 3...
... Replacement pig, 31 ... Body part, 32 ... Recessed groove for resin filling, 33 ... Replacement groove, 34 ... Annular recess,
35... Passage, 36... Pig rear end, 4... Traction cable, 5... Insertion guide tube, 5a... Resin filling port,
5b...Exhaust port, 52, 53...Kotuku, 6
... Leading-out conduit, 6a... Discharge port, 6b...
Pneumatic supply pipe, 61...Opening/closing lock, 7...Resin filling tank, 7a...Hose, 7b...Generator,
7c...Completsa, 9...Winch, 9a...
... Drum, 10... Compressor, 10a... Pressure operation unit, A, B... Pit, C, D... Resin.

Claims (1)

[Claims] 1. Introducing repair resin and a pig that pushes the resin along the inside of the pipe into the pipe of the existing pipe, and the above-mentioned pig attaches to the outer periphery of the pig body that slides in airtight contact with the inner surface of the pipe. A groove for resin filling whose end opens toward the front in the direction of movement, and a groove for replacement whose end opens toward the rear,
The grooves are out of phase in the circumferential direction so that they do not communicate with each other, and the inner ends of both grooves are overlapped in the direction of movement, so that when the pig passes through the pipe joint, In the above structure, the resin is replaced and filled into the space between the pipe joint part through the resin filling groove and the replacement groove, and the outer diameter is narrowed at the rear of the pig body. An annular recess is provided on the rear outer periphery of the pig by forming a small diameter portion, and the rear end of the replacement groove is opened and communicated with the annular recess, and the outer diameter of the pig rearward from the annular groove is connected to the inner surface of the pipe. 1. A pipe joint repair device for an existing pipe, characterized in that the pipe joint is formed to have a predetermined lining distance between the pipe joint and the pipe joint.