JPS6313989A - Method of replacing existing main pipe with novel main pipe - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention provides a method for replacing old pipes buried underground, such as water pipes and gas pipes, with new pipes, and in particular, a method for replacing old and new pipes without digging up the ground surface. It concerns how to replace it.

[Conventional technology] When old pipes, especially cast iron pipes, have aged and become difficult to function after being buried, or when capacity is insufficient due to increased demand and it is necessary to replace them with new pipes, it is necessary to excavate the entire surface above ground. Digging out old pipes is expensive and labor-intensive, and it also obstructs surface traffic, so it is preferable to replace the old and new pipes without digging up the ground.

This is the case with the so-called pipe-in-pipe method, in which a new pipe is inserted into an old pipe underground, but the inner diameter of the new pipe is naturally smaller than the inner diameter of the old pipe, resulting in a reduction in gas and water transport capacity.

The prior art that forms the basis of the present invention is an invention that solves this problem and is described in detail in "Method and Apparatus for Replacing an Existing Main Pipe with a New Main Pipe" (Japanese Patent Publication No. 60-27873 @ Publication Figures 4 to 6). Disclosed.

This conventional technology involves attaching a new main pipe or a liner to protect the main pipe to the rear end of the excavator, which has a body with a larger outer diameter than the old pipe, and moving both of them forward together so that the tip of the excavator enters the old pipe. This is a method and device for replacing the old pipe with a new pipe by crushing it and widening the gap.

The contents will be explained in more detail based on the embodiments of this prior art shown in FIGS. 4 to 6.

The excavation 13a consists of a front part that penetrates into the inner wall of the old pipe 1a and breaks this wall, and a rear part that is fastened to index the new pipe 2a or its liner.

The front part is a head 9 including a cutting edge 12 as a cutting surface.
a, the front end of which is pulled forward by a winch (not shown) via a cable 4a that has been inserted through the row of old tubes.

The new pipe or its liner that will be connected to the excavator later is moved forward by winding the front winch using the cable attached to the front end of the excavator as described above, but in addition to this, as shown in Figure 6, An air hammer 6a is placed inside a hole cut out in the body of the excavator, and an air hose 5 is attached to the rear end.
The piston inside the air hammer slides back and forth by the air supply a, and the forward driving force is impulsively transferred to the excavator.

[Problems to be Solved by the Invention] The present invention is based on the above-mentioned prior art and has developed related technologies so that it can be implemented more effectively.

As shown in Figure 6, the problem with implementation is that the compressed air that is forced into the air hose inserted through the new pipe to drive the air hammer enters the air hammer cylinder from the rear end of the excavator. After the internal piston slides with an impact, the air is discharged from the rear end of the excavator through between the new pipe 2a and the air hose 5a, and is discharged into the starting shaft along the inside of the new pipe.

In devices such as air hammers in which a piston slides within a cylinder, lubricating oil is mixed with compressed air and supplied in the form of a mist in order to continue its operation smoothly. On the other hand, since this lubricating oil is also mixed in the exhaust Ex, it has the disadvantage of adhering to the inner wall of the new pipe when being discharged. The lubricating oil in this new pipe has a negative effect on the water quality during water passage, so it needs to be removed, so it is desirable to remove it from the exhaust Ex in advance, but it is recommended to use a removal and recovery device such as a filter at the excavator's outlet. It is difficult to ensure perfect installation, and if the outlet is blocked, the function of the air hammer may be reduced. Furthermore, it is difficult to completely remove the oil that has adhered to the pipe by washing the pipes, which increases construction costs.

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, it is an object of the present invention to provide a new configuration in which the lubricating oil in the exhaust after operating the air hammer does not adhere to the inner wall of the new pipe that follows.

[Means for solving the problem] The method of replacing the old pipe with a new pipe according to the present invention is such that the exhaust gas after operating the air hammer travels backwards inside the excavator and is discharged into the old pipe in front. Solved the problem.

More specifically, after the air hammer is actuated, the exhaust gas flows backward inside the excavator, and there is a blocking plate that blocks communication of the exhaust gas into the new pipe, and a starting end in front of the blocking plate that passes through the excavating machine in the axial direction. In another aspect, after the air hammer is activated, it connects to the rear of the air hammer, turns around, enters the excavator, and passes through the head of the excavator. It has also been shown that a discharge pipe connected to a channel is preferred.

(Operation and Example) If the compressed air to the air hammer that works together to move the excavator forward drives the piston, it is not discharged into the new pipe, but moves backwards inside the excavator and is discharged into the old pipe in front. It is clear that this produces an effect that can solve the problem. Here, if we trace the behavior of the compressed air based on FIG. 1 showing the embodiment, it is the excavator 3 that is driven forward in order to replace the old pipe 1 with the new pipe 2. Traction force is applied to the head of the excavator via the cable 4 by the winding of a winch (not shown) installed at the front, while a compressor (not shown) at the rear is applied to the head of the excavator.
Compressed air is sent to the rear through the air hose 5.

An air hammer 6 is built inside the excavator 3, and a piston (not shown) is activated by the action of compressed air and a valve (not shown).
The robot slides with an impact, and a forward driving force is applied. In this example, the compressed air that operated the air hammer is discharged into the excavation area outside the air hammer through the rear exhaust hole 7 located at the rear of the air hammer, but is blocked by a blocking plate 8 provided at the rear end of the excavator from the new pipe that follows. communication is cut off, and the exhaust Ex passes through the body of the excavator in the axial direction and opens into the head 9 of the excavator in front of the flow path 1.
0 into the old pipe 1.

In this example, the flow path 10 includes a rear exhaust passage 10A bored at the rear of the excavator, and a gap 10B formed between the excavator body wall and the air hammer.
As shown in FIG. 2, a front exhaust passage 10C that opens radially is connected to the head of the S excavator.

FIG. 3 is a front sectional view showing another embodiment, in which the exhaust hose 11 is connected to the rear end of the air hammer instead of the blocking plate of the previous example, and the exhaust hose 11 is reversed and inserted forward in the axial direction into the cavity 10B inside the excavator. It is connected to the front exhaust passage 10C that opens radially in the head to form one flow passage.

[Effects of the Invention] As described above, the present invention performs a lubrication-like action, so the lubricating oil mixed in the mist in the exhaust air does not adhere to the inner wall of the new pipe to be replaced, and the pipe can be used as a water supply pipe as it is. There is no risk of water quality deterioration or toxicity even when used.

Further, since there is no need to take measures against lubricating oil mixed in the exhaust gas, the burden on workability and economy can be reduced.

Furthermore, for existing excavators used in conventional technology, the method of the present invention can be easily implemented with relatively simple modification, and by adopting such an exhaust method, there is no possibility of a decrease in driving capacity. .

[Brief explanation of the drawing]

FIG. 1 is a front sectional view showing an example of the implementation of the present application, FIG. 2 is a side view of the excavator head of the same embodiment, FIG. 3 is a front sectional view showing another embodiment, and FIGS. The figure is a front view of the conventional technology. Figure 6 is a partial front view explaining the problems of the conventional technology.

Claims (3)

[Claims] (1) Existing main pipes buried underground (hereinafter referred to as “old pipes”)
Attach a new main pipe (hereinafter referred to as the "new pipe") to the rear end of the excavator, which has a body with a larger outer diameter than the main pipe (hereinafter referred to as "the new pipe"), pull the head of the excavator from the front, and insert the new main pipe into the new pipe. The air hammer inside the excavator is activated by the pressurized air sent from behind through the air hose, and the excavator and new pipe move forward together, and the tip of the excavator enters the old pipe, crushing it and pushing through the gap. A method of replacing an old pipe with a new pipe by expanding it, characterized in that the exhaust gas after operating an air hammer travels backwards inside the excavator and is discharged into the old pipe in front. (2) Reverse movement of exhaust gas inside the excavator is achieved by a blocking plate that blocks communication of the exhaust gas into the new pipe after the air hammer is activated, and a starting end in front of the blocking plate that penetrates the excavating machine in the axial direction. A method for replacing an old pipe with a new pipe according to claim 1, which is based on a flow path opening into the old pipe at the front. (3) Reverse flow of exhaust gas inside the excavator is caused by the exhaust pipe that connects to the rear of the air hammer after the air hammer is activated, reverses itself, enters the excavator, and connects to the flow path that passes through the head of the excavator. A method for replacing an old pipe with a new pipe according to claim 1.