JPH0326308B2 - - Google Patents

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, gas pipes, etc., with new pipes, in particular, 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 there is a shortage of capacity due to increased demand and there is a need to replace them with new pipes, it is necessary to excavate the entire surface above ground and excavate the old pipes. The method of installing new pipes is expensive and labor-intensive, and it also obstructs surface traffic, so it is preferable to replace old and new pipes without digging up the surface.

This is the case with the so-called pipe-in-pipe method, in which a new pipe is inserted into an old underground pipe, 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, ``Method and Apparatus for Replacing an Existing Main Pipe with a New Main Pipe'' (Japanese Patent Publication No. 60-17873, Figure 3~
(Fig. 5). FIG. 6 is taken from a catalog explaining the state of the invention when it is implemented on a commercial basis.

This conventional technology attaches a new main pipe or a liner to protect this main pipe to the rear end of the excavator, which has a body with a larger outer diameter than the old pipe, and both move 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 entering the pipe, crushing it, and expanding the gap.

The contents will be explained in more detail based on the embodiments of this prior art shown in FIGS. 3 to 5.

The excavator 3a 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 pull the new pipe 2a or its liner. The front part has a head 12 that includes a cutting edge 11 as a cutting surface, and its front end is moved forward by a winch (not shown) via a cable 5a that has been inserted through the tube row of the old pipe. I am drawn to it.

The cutting edge 11 includes vanes 13, at least one of which can be pivoted radially outwardly from the excavator to effectively fracture the wall of the old pipe.

In Fig. 4, the fluid (hydraulic pressure) pumped through the fluid pressure hose 14 that has hidden inside the old pipe and extended from the front pushes up the piston 15 installed in the head of the excavator, and is pushed up by this piston. One end of the blade 13 is pushed up to increase the inclination angle,
This causes an action to push the existing pipe 1a outward in the radial direction from the inner wall.

This excavator and the new pipe or its liner that will be connected later are moved forward by the winding of the front winch using the cable attached to the front end of the excavator as described above, but in addition to this, the The air hammer 16 is inserted into the hole cut out in the body of the excavator.
An example is also shown in which a piston in the air hammer is slid back and forth by air supplied from an air hose 7a attached to the rear end, and a forward driving force is applied to the excavator with an impact. This publication also shows another example of a rotating mechanism for the cutting edge, but this is omitted.

On the other hand, Fig. 6 is a diversion from a commercial document showing the implementation of this invention, but as shown in the figure, the main subject of this invention was originally a gas pump replacing an old cast iron pipe 1a with a new plastic pipe 2a. The new pipe is a continuous, long pipe with a small diameter and great flexibility.

Generally, new mains are made of materials such as polyethylene, and to compensate for its lower mechanical strength (external pressure resistance, abrasion resistance), much stronger plastics such as PVC resin are used. A protective liner made of a material is used, and the method typically used is to replace the old pipe with the protective liner and then insert the new main pipe into the protective liner.

In the figure, 17 is a winch for forward traction.

[Problem that the invention seeks to solve]

The present invention is based on the above-mentioned prior art and has developed related technologies to enable more effective implementation.

As a practical problem, an air hose for operating an air hammer inside the excavator is connected from the rear to the rear end of the excavator. It is also conceivable to connect an oil supply pipe that provides oil pressure for rotating the blades.

When the new tube is a real long flexible plastic tube, such tubes may be inserted into the tube in advance and moved forward in a bendable manner as the new tube advances. It can be said that FIG. 6 shows just such an embodiment. However, when the new pipe is made of a rigid material and has a rigid shape, such a flexible embodiment is not possible. For example, the caliber
If the length exceeds 200 mm, even plastic pipes cannot be replaced as a continuous body, and this goes without saying for steel pipes and cast iron pipes.

It is undesirable to lengthen the starting shaft to replace a long, rigid new pipe in terms of work loss and traffic obstruction. If possible, it would be reasonable to keep the new pipes short and replace them one after another and add more from behind as they progress, but piping from compressors and hydraulic equipment installed on the ground must be inserted smoothly into the new pipes. .

In order to solve the above-mentioned problems, the present application aims to provide a method that allows pipes such as hoses to be easily inserted into short new pipes.

[Means for solving problems]

The method of replacing an old pipe with a new pipe according to the present invention is to first pass a slit parallel to the axial direction into the new pipe before installation, and then install an excavator from the starting shaft into the old pipe to crush it horizontally. After the air hose connected to the rear of the excavator is inserted into the new pipe through the slit, the new pipe is attached to the rear end of the excavator by welding or fusing the slit. The pipe advances horizontally underground, and before the rear end of the new pipe enters the ground, the air hose passes through the slit and continues with the next new pipe inserted into the pipe, and the new pipe welds the slit. Alternatively, the air hose can be fused and connected to the rear end of the preceding new pipe, and then the above procedure can be repeated to continuously connect new pipes to form a new pipe line, and then the air hose can be removed from the pipe line. I was able to solve the problem.

[Function and Examples]

FIG. 1 is a perspective view of a new pipe 1 showing an embodiment of the present invention, and its feature is a slit S cut parallel to the axial direction (longitudinal direction) of the pipe.

FIG. 2 shows an embodiment in which such a new pipe is used to replace the new pipe with the old pipe, and the new pipe is limited to materials that can be welded or fused due to the nature of the invention. Typical examples include steel pipes or thermoplastics, such as polyethylene pipes. However, since the conventional technology (Fig. 6) is sufficient for thin plastic tubes with a diameter of 200 mm or less, the new tube will demonstrate its value in rigid short tubes of medium diameter or larger that have lost their flexibility.

An example of the construction method will be explained based on Fig. 2 A, B, C, D, and Ho. Figure A is a front view illustrating the entire process, and the steps are listed as follows.

(1) Attach excavator 3 to the starting end of the old pipe 1 row.
Therefore, the starting shaft 4 is dug from the ground surface to a length that exposes the starting end and accommodates the related equipment.

(2) A towing cable 5 is attached to the tip of the excavator by passing through the old pipe in front, and connects it to the winding force of a winch (not shown) installed in the front and to the compressor 6 in the rear. Connect air hose 7.

(3) Pressurized air is sent from the air hose connected to the rear end of the excavator to activate the air hammer inside the excavator, causing it to move forward while destroying the old pipe.

(4) Advance the excavator to a predetermined length (just before the rear end of the excavator goes into the ground).

(5) New pipe 2 with slits S cut in advance after or prior to this as shown in Figures B and C.
is lowered into the starting shaft 4, and the air hose 7 (and the hydraulic hose 8 if necessary) connected to the rear end of the excavator 3 is inserted into the pipe through the slit S.

(6) Weld or fuse the slit S as shown in Figure D.

(7) As shown in Figure E, connect the new pipe with hoses inserted to the rear end of the excavator or the rear end of the pipe that follows the excavator.

Connections are made by known methods such as welding, fusion bonding, water seal packing, and bolting.

(8) Move the excavator forward by the length of one new pipe.
(The new pipe following the excavator is also towed by the excavator and laid underground.) (9) After that, repeat steps (5) to (8).

(10) When the excavator reaches the reaching shaft and has inserted the desired number of new pipes into the crushed old pipes, connect the air hose and hydraulic hose connected to the excavator at the rear end of the excavator. Remove from the excavator.

(11) Wind up the hoses inserted into the new pipe row with the hose reel in the starting shaft.

A feature of the present application is how the air hose, preferably wound on a hose reel on the ground, is unwound in synchronization with the advance of the excavator and inserted into the pipe of the short new pipe to be replaced. In addition, as shown in the figure, there may be cases where it is necessary to insert the oil supply pipe 8 from the hydraulic unit 9 into the new pipe for supplying hydraulic pressure from the hydraulic unit to the rear end of the excavator. In this case, the new pipe installed at the rear end of the excavator has a slit S as shown in Figure 1, so the air hose and oil supply pipe are inserted into the pipe through the slit S.
After fitting, it may be welded or fused. Preferably, the slit S is formed when the bolt is inserted.
A possible method is to press the slit portions apart during welding or fusion, making the work easier. In the case of steel pipes, it can be easily welded using the automatic welding machine 10 in the starting shaft, and in the case of thermoplastic plastics (polyethylene pipes), it can be welded by pressing a hot plate (electric heater at around 220°C) and applying pressure to the slit part. Easily fused.

〔Effect of the invention〕

Since the present invention achieves the above-described structure and operation, there is no need to insert desired pipes such as an air hose into the long new pipe extending over the entire pipe line from the beginning. Therefore,
The work space required for construction is small, and the work efficiency and road traffic support are reduced.

New pipes have practical advantages, especially in the case of rigid medium-diameter pipes, and are also advantageous in terms of economy, since the pipes can be cut into short lengths and transported easily, and the scale of the starting shaft can be small.

Furthermore, since the air hose wound around the hose reel is unwound in synchronization with the forward movement of the excavator, the work space can be reduced and work efficiency is improved. Furthermore, the air supply to the air hammer is not stopped.

[Brief explanation of drawings]

Figure 1 is a perspective view showing the embodiment of the present application, Figure 2 A is a front sectional view showing the construction work being carried out in the present application, Ro to Ho are perspective views showing the construction procedure, and Figures 3 to 5 are FIG. 6 is a front view or front sectional view showing an example of a conventional technique; FIG. 6 is a front sectional view illustrating a general construction example of the conventional technique. 1... Old pipe, 2... New pipe, 3... Excavator, 7...
...Air hose, S...New pipe slit.

Claims (1)

[Claims] 1. Existing main pipes buried underground (hereinafter referred to as “old pipes”)
A new main pipe or a liner that serves as a protective sleeve for the new main pipe (hereinafter referred to as "new pipe") is attached to the rear end of the excavator, which has a body with a larger outer diameter (hereinafter referred to as "new pipe"), and the front part of the excavator is towed from the front. At the same time, the air hammer inside the excavator is actuated by the pressure air sent from behind through the air hose inserted into the new pipe, so that the excavator and the new pipe move forward together, and the tip of the excavator enters into the old pipe. In the method of replacing the old pipe with a new pipe by expanding the gap while crushing the new pipe, a slit parallel to the axial direction is penetrated through the new pipe before installation, and the first step is to drill from inside the starting hole into the old pipe. The machine is attached and moves forward horizontally while crushing, and the air hose connected to the rear of the excavator is inserted into the new pipe through the slit.The new pipe is attached to the back of the excavator by welding or fusing the slit. The excavator and the new pipe move horizontally underground, and before the rear end of the new pipe enters the ground, the air hose passes through the slit and continues to the next new pipe that is inserted into the pipe. The new pipe is connected to the rear end of the preceding new pipe by welding or fusing the slit, and the procedure is repeated to connect the new pipes continuously to form a new pipe line, and then connect the air hose to the pipe line. A method of replacing an old pipe with a new one, which involves removing it from the pipe.