JPH0562280B2 - - Google Patents

Description

[Detailed description of the invention] [Industrial application field]

The present invention is a method for plugging corrosion holes or removing existing pipes such as communication cables, etc., which are mainly laid underground, or existing pipes such as gas pipes from within the pipes while still buried. The present invention relates to a repair method for existing piping that involves forming a resin lining coating on the inner surface of the pipe for reinforcement.

[Conventional technology]

Existing piping, which serves as a lead-in conduit for communication cables buried underground, is laid under roads, so over many years it has been damaged by vibrations from vehicles passing on the road, earthquakes, etc. Groundwater, etc. can enter into pipes due to changes in the joint condition of pipe joints, creating gaps in pipe joints, or corrosion holes forming due to deterioration of pipe walls over time. There was an inconvenience. Therefore, recent efforts have been made to repair the pipe by forming a resin lining coating on the inner surface of the pipe in order to close the corrosion holes and reinforce the pipe. As a type of repair method, a repair resin and a pig that pushes the resin from behind are introduced into the existing pipe buried underground, and the resin is pulled by the pig. In the process of moving along the pipe from one separation opening to the other, the resin flows backward from the gap between the outer periphery of the pig and the inner surface of the pipe, and the required amount is applied to the inner surface of the pipe. A method of repairing existing pipes by forming a thick lining coating film has been proposed, for example, in Japanese Patent Publication No. 58-50779.

[Technical problem of the invention]

In the above repair method, the thickness of the resin lining film formed on the inner surface of the pipe depends on the resin pressure generated in the resin just in front of the pig due to the viscous resistance between the resin and the inner wall of the pipe due to the traction movement of the resin. This resin pressure varies depending on the amount of resin injected in front of the pig (resin length), the pulling speed of the pig, etc. Therefore, at the initial stage of the repair section, the amount of resin is large and the resin pressure is high, resulting in a thick lining coating film, and as the repair progresses, in the later stages of the repair, as the amount of resin on the front side of the pig decreases. As the resin pressure gradually decreases, the thickness of the resin lining coating also changes to become gradually thinner. In order to compensate for this decrease in thickness and form a resin lining film with a uniform thickness over the entire length of the pipe, there is a conventional construction method that changes the pulling speed of the pig. The traction speed must be changed sequentially according to a program, which has the problem of complicating the device and causing problems such as the actual thickness often not being uniform.

[Purpose of the invention]

The present invention was proposed to address the above-mentioned problems, and is designed to make the thickness of the resin lining coating film uniform even if the amount of resin (resin pressure) changes as the repair progresses. By controlling the lining gap between the outer circumference of the pig and the inner surface of the pipe in a predetermined proportional relationship with the resin pressure, which is directly related to the thickness of the lining film, a resin lining film with a uniform thickness is formed over the entire length of the pipe. The purpose of this project is to provide an improved method for repairing existing piping.

[Means to achieve the purpose]

In order to achieve this object, the present invention has a structure in which a hollow pressure chamber is provided inside the pig that pushes the resin so that the outer periphery of the pig can be expanded and contracted in the radial direction. Equipped with a pressure sensor that detects resin pressure, the resin pressure detected by the sensor is converted into a signal that has a predetermined proportional relationship according to the set parameters, and the oil pressure and pressure are adjusted according to this signal. By introducing the resin into the pressure chamber of the pig through the valve, the lining gap formed between the outer periphery of the pig and the inner surface of the pipe corresponds to the amount of resin (resin pressure), thereby achieving the desired thickness. It is characterized in that the resin lining coating can be formed uniformly over the entire length of the pipe.

【Example】

Hereinafter, one embodiment of the method of the present invention will be specifically described with reference to the drawings. Figure 1 is a diagram schematically showing the state of repair work, and in the diagram, reference numeral 1 indicates a part of the existing pipe (lead pipe for communication cables, etc.) that is to be repaired and is installed underground under the road. It is. This existing pipe 1 is generally laid long under the road via a manhole, and the space between the manholes is used as one unit of repair space, and inside the manhole with one separated open end opened, A pig 2 is introduced into the existing pipeline 1 through the separation opening, and the pig 2 is attached to a tow rope 3 that is passed through the pipe so that the pig 2 is towed along the interior of the pipeline 1 by the tow rope 3. It is being When the pig 2 is introduced, a resin D, for example, an epoxy resin, is injected into the tube on the front side of the pig 2. As shown in FIG. 3, the pig 2 has a truncated conical head piece 21 made of a hard elastic material, such as neoprene rubber with a hardness of about 60 degrees, on the forward end side in the direction of movement. The body piece 22 is made of a cylindrical soft elastic material, such as a hard neoprene sponge having a hardness of about 50 degrees, and is held between support disks placed at the front and rear ends of the body piece 22. A pressure sensor 41 is embedded in the conical surface of the head piece 21 to detect the pressure of the resin D immediately before the pressure sensor 41, which is externally connected via the pig introduction opening by a signal cable 42. control panel 4 (see Figure 2)
connected to. Further, a pressure chamber 23 is formed hollow inside the body piece 22.
3, pressure oil from a hydraulic pump 52 driven by a motor 51 in the hydraulic circuit 5 shown in FIG. The outer peripheral surface of the pig 2 can be expanded and contracted in the radial direction. During repair work, the above-mentioned pig 2 is pulled by a tow rope 3 by driving a winch and is towed inside the existing pipeline 1 from the introduction side to the other end. It is pushed and moved inside the pipe, and during this movement, the resin D flows backward from the gap between the outer peripheral surface of the pig 2 and the inner surface of the pipe, and forms a resin lining coating on the inner surface of the pipe inside the existing pipe 1. 1
d is formed. The thickness of the resin lining coating film 1d formed in this way depends on the resin pressure of the resin D pushed by the pig 2, especially the resin pressure generated on the resin D immediately before the pig 2, so the present invention Then, as the repair progresses, the resin pressure is detected by a pressure sensor 41 made of a strain gauge, etc., and transmitted to the amplifier 43 of the control panel 4 via the signal cable 42, where it can be set arbitrarily by the setting device 44. A drive motor 46 amplifies and converts the signal into a signal that has a predetermined proportional relationship with the resin pressure according to parameter values set in , and operates the pressure regulating valve 53 in the opening or closing direction via the motor drive circuit 45. to drive. As a result, the hydraulic pump 52
The pressure oil is bypassed by the pressure regulating valve 53 to adjust its oil pressure, and pressure oil corresponding to the resin pressure is introduced into the pressure chamber 23 via the hose 54. When equipped with the above-mentioned means, the pressure of the resin D immediately in front of the pig 2 caused by traction can be detected by the pressure sensor 4.
1, and in the amplifier 43, it is converted into a signal having a predetermined proportional relationship to the resin pressure according to the parameters by the setting device 44, and further converted into an oil pressure having a predetermined proportional relationship via the pressure regulating valve 53. The sliding surface pressure generated between the outer circumferential surface of the pig 2 and the inner circumferential surface of the existing pipe line 1 (lining gap) due to this oil pressure via the pressure chamber 23 becomes a surface pressure corresponding to the resin pressure, and the pressure on the inner circumferential surface of the pipe A uniform resin lining coating film 1d having a desired thickness according to the set parameters is formed over the entire length of the pipe. In this way, the factor that influences the thickness of the lining coating film 1d (pressure of the resin D) is directly detected, and the sliding surface pressure between the pig 2 and the inner surface of the pipe is set accordingly. It becomes possible to maintain uniform thickness from the initial stage to the final stage of the repair section. In addition, since the operation is performed using hydraulic pressure, there is no delay in signal transmission, and thickness control has good followability, and resin pressure can be adjusted due to changes in pulling speed, changes in tube inner surface shape, or fluctuations in air pressure in front of the pig. Be able to respond quickly to changes. In addition, as the above-mentioned pig 2, the resin D is inserted into the existing pipe 1 with an opening toward the front side in the traveling direction on the outer peripheral surface of the pig.
A plurality of grooves for introducing resin into the pipe joint, and a plurality of escape grooves that open rearward to replace the introduced resin with air accumulated in the pipe joint and release it to the rear. By using a replacement pig provided with the strips, it is possible to more reliably fill the pipe joint portion with the resin D. Furthermore, if a plurality of fin pieces are provided at the rear of the outer circumferential surface of the pig 2 to form circumferential grooves, the pressure of the resin D sliding between the outer circumferential surface of the pig 2 and the inner surface of the tube can be reduced. It can be made uniform in all directions, and is more effective in forming a uniform resin lining coating film 1d. When forming the resin lining coating film 1d in this way, if you want to set the thickness of the lining coating film to a required thickness, you can arbitrarily set the desired thickness by changing the proportional relationship parameter value using the setting device 44. The resin lining coating film thus formed can be set to have a desired uniform thickness.

【Effect of the invention】

Since the present invention is a repair method as described in detail above, when carrying out repairs such as forming a resin lining film by towing and moving a pig within the existing pipeline in the repair section, The thickness of the resin lining coating film to be formed can be uniformly formed at any desired thickness over the entire length of the coating film, and the controllability thereof is extremely good.

[Brief explanation of drawings]

FIG. 1 is a schematic diagram showing an embodiment of the repair method according to the present invention, FIG. 2 is a block diagram of a resin lining coating thickness control circuit, and FIG. 3 is a schematic diagram showing the configuration of a pig. 1... Existing pipe line, 1d... Resin lining coating film, 2... Pig, 21... truncated conical head piece,
22... Body piece, 23... Pressure chamber, 3... Traction cable, 4... Control panel, 41... Pressure sensor, 42...
... Signal cable, 43 ... Amplifier, 44 ... Setting device for setting parameter values, 45 ... Motor drive circuit, 46 ... Drive motor, 5 ... Hydraulic circuit,
51...Motor, 52...Hydraulic pump, 53...
Pressure regulating valve, 54...hose.

Claims (1)

[Claims] 1. A resin and a pig that pushes the resin from behind are introduced into the pipe of an existing pipe such as a communication pipe laid underground, and the resin is pulled by the pig. During the pushing process, the gap between the outer periphery of the pig and the inner surface of the tube is used as a lining gap, and the resin flows backward from the gap to form a lining coating film of the required thickness on the inner surface of the tube. The resin pressure generated just before the pig due to the movement of the resin is detected by a pressure sensor installed on the front side of the pig, and this detection signal is used to control fluctuations in resin pressure due to changes in resin amount in a predetermined proportional relationship. The hydraulic pressure is introduced into the hollow pressure chamber formed inside the pig, so that when the amount of resin is large and the resin pressure is high, the outside diameter of the pig is expanded, and when the amount of resin is small and the resin pressure is low, the outside diameter of the pig is expanded. When the outer diameter of the pig is small, the outer diameter of the pig is expanded or contracted by the resin pressure detection signal to change the lining gap, and the thickness of the resin lining coating formed on the inner surface of the pipe is adjusted. A method for repairing existing piping, characterized by making it possible to uniformly form the pipe to a desired value over the entire length of the pipe.