JPH0240387B2 - KISETSUKANNOKANNAIMENHOSHURAININGUYOPIGUNOKOZO - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention mainly relates to the structure of a lining pig used for repairing the inner surface of an existing pipe such as a gas pipe buried underground.

[Conventional technology]

A known repair method is to apply resin lining to the inner surface of existing gas pipes while they are still buried to improve their durability against corrosion and pressure resistance.

In this method, a pig is passed through the existing pipe, and while the pig is pulled by a towing cable, the coating resin placed on the front side of the pig is coated on the pipe wall using the clearance between the pig and the inner wall of the existing pipe. There is.

[Problem to be solved by the invention]

The problem in this case is that the thickness of the lining layer changes between the initial and final stages of lining. In other words, in the early stages of lining, there is a large amount of resin on the front side of the pig, and this creates viscous resistance when it comes into contact with the inner wall of the existing pipe, and the load on the pig when pulling the tow rope is large, causing the pig to pass through the clearance with the existing pipe. The lining layer is reduced in the radial direction by the resin pressure, and the lining layer becomes thicker, but in the final stage, the amount of resin on the front side of the pig decreases, the resin pressure passing through the clearance decreases, and the pig returns to its radial direction. As the process progresses, the lining layer becomes thinner. In particular, this effect becomes significant when the length of one lining of the existing pipe becomes as long as 100 m to 200 m.

The present invention has been made based on the above-mentioned circumstances, and it is possible to make the thickness of the lining layer in the existing pipe uniform by preventing the diameter of the pig from being changed depending on the amount of resin on the front side of the pig. The purpose of the present invention is to provide a structure of a pig for repairing and lining the inner surface of a pipe.

[Means to solve the problem]

In order to achieve this object, the present invention creates a hollow space inside a pig 1 that moves inside a pipe A while being towed by a tow rope 8, pushes the lining resin B on the front side of the pig 1, and lines the inner wall of the pipe. 9 is provided, and this hollow portion 9 is made to communicate with the resin B via a communication path 10 provided on the front side of the tow.

[Effect]

With the above structure, when the amount of the front lining resin B in the hollow part 9 of the moving pig 1 is large, the internal pressure becomes high and is balanced with the pressure on the outside of the pig 1. When the amount of lining is small, the internal pressure in the intermediate portion 9 is high and balanced with the external pressure, so that lining with a substantially constant thickness is always achieved.

〔Example〕

Hereinafter, one embodiment of the present invention will be specifically described with reference to the drawings. In the figure, numeral 1 is a pig body made of, for example, neoprene sponge,
Support members 2 and 3 made of a hard rubber material are provided on the front and rear sides of the support members 2 and 3, and furthermore,
Attachment members 4 and 5 are attached. The attachment members 4, 5 are fixed to a towing line 8, such as a wire, by collars 6, 7 with clamps. Also,
The pig body 1 has a hollow chamber 9 therein, and this hollow chamber 9 is opened to the front side of the pig via a communication passage 10.

FIG. 2 shows a situation in which an existing pipe A is lined with resin using a pig having such a configuration. Here, the resin B is located on the front side of the pig, and is filled up to the hollow chamber 9 through the communication passage 10 when the tow rope 8 is towed. When towing is performed in this state, the clearance C between the outer circumference of the pig and the existing pipe A is
In the initial stage of lining, resin B and existing pipe A
Since the viscous resistance with the inner wall of the pig body 1 is large in proportion to the amount of resin, the resin pressure passing through the clearance C is high, but the same resin pressure is applied inside the hollow chamber 9 and supports the outer circumferential wall of the pig body 1 from the inside. It becomes constant depending on the balance between the two. Moreover, this condition is the same at the final stage of lining, and when the resin pressure passing through the clearance C decreases, the resin pressure in the hollow chamber 9 is also low, so the conditions are not different from those in the initial stage. Therefore, the clearance C is constant.

In this way, the diameter of the pig does not substantially change from the initial stage to the final stage, and therefore, the resin lining layer is formed in the existing pipe A with a constant thickness.

〔Effect of the invention〕

As described in detail above, the present invention makes the inside of the pig hollow so that the resin pressure on the front side of the pig is applied therein, so that the resin pressure fluctuation is the same as the resin pressure fluctuation in the clearance between the pig and the inner wall of the existing pipe. By bringing this inside the pig and thereby keeping the diameter of the pig constant, an excellent effect can be obtained in that the internal resin lining of the existing pipe to be repaired can be substantially uniform in thickness.

[Brief explanation of drawings]

FIG. 1 is a partially cutaway perspective view showing an embodiment of the present invention, and FIG. 2 is a longitudinal sectional side view showing a mode of use. 1... Pig body, 2, 3... Support member, 4, 5... Mounting member, 6, 7... Collar, 8... Traction cable, 9... Hollow chamber, 10... Communication path, A... Existing pipe, B... Resin, C
…clearance.

Claims (1)

[Claims] 1. A hollow part 9 is provided inside the pig 1, which moves inside the pipe A while being towed by a tow rope 8, and pushes the lining resin B on the front side to line the inner wall of the pipe. Communication path 1 provided on the front side of the tow
The structure of a pig for repairing and lining the inner surface of an existing pipe, characterized in that it communicates with resin B through 0.