JPH0211796B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for restoring the function of an existing underground pipe.

Cast iron pipes, steel pipes, asbestos pipes, etc. are used for water pipes and gas pipes, but over time rust and deposits develop on the inner surface of the pipes, resulting in a decrease in flow rate. This can cause the formation of foul-smelling red water. Also, gas or water may leak from the connections, or bad water may enter.

Restoring the functionality of existing underground pipes that have deteriorated over time is in great need, and efforts have already been made to clean the inside of the existing pipes and insert or bond pipes made of plastic, rubber, or other materials to the inner surface of the existing pipes. The construction method is known. However, these are the first
As shown in the figure, in most cases there is a branch pipe (side pipe 1). (For the time being, the branch pipe is defined as a side pipe to distinguish it from the main pipe, which is the main pipe. In the present invention, the functional recovery of the main pipe is discussed, and in FIG. 1, 1 is the side pipe and 2 is the main pipe. ) According to the existing method described above, the inner surface of the main pipe is protected and is useful for restoring functionality, but there is a problem in that the flow path to the side pipe is cut off, making it impossible to obtain diversion to the side pipe. Fig. 2 shows the condition, where 1 is a side pipe, 2 is a main pipe, and 3 is a plastic pipe.

The present invention solves the above-mentioned problems, and as shown in FIG.
By inserting the plastic tube 3 into the side tube, increasing the temperature until it becomes soft, and creating a vacuum inside the side tube 1, the plastic tube 3 is stretched and drawn into the side tube, and a thin plastic material is formed along the inner wall of the side tube. Once the tube 3' has formed, it is cooled to maintain its shape, the vacuum is stopped, and pressure is applied inside the tube with a fluid (water, air, etc.) to remove the thinning and swollen plastic layer inside the side tube. It is characterized by tearing and opening a hole in the side tube part.

Embodiments of the present invention will be described using FIGS. 3 to 5.

To restore functionality by rehabilitating the inner surface of underground pipes used for circulating fluids such as water and gas, manholes are installed at regular intervals (for example, 100 m or 200 m).
Work will be carried out by cutting a portion of the existing pipe at that location.

Therefore, the existing pipe between one manhole and the next becomes one work unit. For example, the first
Considering the case of a water pipe that distributes water to each household through a side pipe 1 as shown in the figure, a plurality of side pipes branch off from the main pipe 2 of one working unit.

Therefore, after inserting a plastic pipe into the main pipe and repairing it, the entire length of the inside of the pipe or a portion of the side pipe is heated, the inside of the side pipe is evacuated, and the plastic pipe 3 is inserted into the side pipe 1 as shown in FIG. After pulling it into the tube, inflating it thinly and stretching it out, and applying it to the inner wall of the side tube,
The heating is stopped, the plastic inside the tube is allowed to cool, and the elongated shape is maintained before the vacuum is stopped. After that, one end of the tube is sealed with, for example, a blank flange, and internal pressure from water or air is applied from the other end to try to break the plastic tube 3 in the side tube, as shown in FIG.

In this case, if the stop valve 4 (for example, a water stop valve) of each side pipe 1 is closed as shown in FIG.
Internal pressure is applied to a plurality of side pipes included in one work unit at the same time, making it possible to open holes in all of them at once. In addition,
5 is a flange, and 6 is a pressure gauge.

In the method of the present invention, a bag-shaped plastic stretched thinly by vacuuming is destroyed by internal pressure at room temperature, resulting in large openings.

Explain that a plastic tube is a good tube to insert inside the main pipe.

First of all, plastics have a softening point. Plastic loses its strength as its temperature increases, so it can be easily expanded after being drawn into the side tube.

Next, since plastic is a plastic material, if it is swollen in the side tube and cooled, the swollen state of the plastic tube will remain as it is. However, in the case of a tube made of an elastic material such as rubber, when the pressure difference disappears, it returns to its original state and becomes blocked. That is, as mentioned above, one of the important features of the present invention is the use of plastic tubes.

The plastic tube may be a tube made of a single type of simple material, or may have a structure made of braided plastic threads of greater strength, or it may be a plastic tube whose molecules are cross-linked in some way.

In short, any tube may be used as long as it is mainly made of a material (plastic) that has a softening point.

Note that if a tube is made mainly of appropriately cross-linked plastic, it will be possible to create a larger bulge when evacuated under heating, so depending on the size of the opening required, It is preferred to use a tube made primarily of cross-linked plastic.

The method of drawing a vacuum from the side pipes will vary depending on the location and the number of side pipes in one work unit, but for example, in a water piping system where the side pipes connect to each home. To do this, simply remove the valve installed on the water meter and connect the vacuum piping to it. Further, evacuation may be performed by connecting each pipe to one vacuum pump regardless of the number of side pipes, or by evacuation of each side pipe one by one.

On the other hand, regarding the method of raising the temperature of plastic pipes, the purpose can be easily achieved by injecting high-temperature gas such as steam into the main pipe.

As explained above, the method of opening a hole in the side pipe portion of an existing buried pipe according to the present invention is an extremely effective and appropriate means without causing a situation where it becomes impossible to obtain diversion to the side pipe.

[Brief explanation of drawings]

Fig. 1 is an explanatory diagram of the main pipe and side pipe of the buried pipe, Fig. 2 is an explanatory diagram of the existing construction method for restoring the function of the existing buried pipe, and Figs. 3 to 5 are all the side pipe parts of the present invention. Regarding the hole opening method, Fig. 3 is an explanatory diagram in which a plastic pipe for rehabilitation is inserted into an existing pipe, and the plastic pipe is stretched into the side pipe by vacuuming the side pipe, creating a thin plastic pipe section. Figure 4 is an illustration of how the thin plastic pipe shown in Figure 3 ruptures due to fluid pressure, and Figure 5 is an illustration of how a stop valve is used to simultaneously open all the side pipes in one work unit. It is a diagram. 1... Side pipe, 2... Main pipe, 3... Plastic pipe (for rehabilitation), 3'... Plastic pipe stretched thinly into the side pipe, 4... Stop valve (water stop valve), 5... Flange, 6...Pressure gauge.

Claims (1)

[Claims] 1. A rehabilitation pipe is inserted into an existing buried pipe for fluid transport whose inner surface has been cleaned in advance, and then heated and then evacuated from the side pipe section. After cooling, the inside of the main pipe is A method for opening a hole in a side pipe of an existing buried pipe, the method comprising opening a hole in the side pipe by applying pressure. 2. A method for opening a hole in a side pipe of an existing buried pipe according to claim 1, using a pipe mainly made of plastic as the rehabilitation pipe. 3. A method for opening a hole in a side pipe of an existing buried pipe according to claim 1 or 2, using a pipe mainly made of cross-linked plastic as the rehabilitation pipe. 4. A method for opening a side pipe of an existing buried pipe according to claim 1, 2, or 3, which uses high-temperature steam or air to heat the entire length of the rehabilitation pipe or the side pipe. .