JPH115171A - Pipe member cutting method and machine therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a processing period and expenses by easily and surely cut the pipe, an inner circumference surface of which is coated by a lining consisted of a non-electroconductive material, by laying an electroconductive member between a torch of a plasma arc cutting machine movable in the pipe, and the pipe lining, to generate the plasma arc between the torch and the electroconductive member. SOLUTION: A cutting machine 18 put into a given position of the buried pipe 1 cuts the electroconductive member 14 by the arc generated between an electrode 19 and the electroconductive member 14 comprised of a steel sheet and the like plated on the inner circumference surface of the lining 3. The plasma arc cut the electroconductive member 14 cuts the lining 3 and the pipe body 2. The electroconductive member 14, the lining 3 and the pipe body 2 are integrally cut in a circumferencial direction by rotating the torch 19 of the cutting machine 18 in a circumferencial direction of the buried pipe 1. The buried pipe 1 cut by laying the electroconductive member 14 between the torch 19 and the buried pipe 1. The cutting machine 18 is moved in the buried pipe by a given distance to conduct a next cutting.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe cutting method suitable for removing, for example, aged water pipes and the like, and a cutting machine used therefor.

[0002]

2. Description of the Related Art Conventionally, when a buried pipe (pipe) buried in the ground, such as a cast iron or steel water pipe, is to be removed due to aging or the like, both sides of the pipe are to be removed along the buried pipe. After excavating the ground and exposing the buried pipes, the buried pipes are cut into a length that can be removed and carried out by a gas cutter or the like, and are removed from the ground. After that, new pipes are installed and backfilled as necessary.

However, in order to perform a cutting operation using a gas cutting machine or the like, it is necessary to excavate all the buried pipes and to provide a space on the side of the buried pipes for a worker to enter and perform work. Therefore, the depth to be excavated is increased and the interval between sheet piles is widened. As a result, the excavated soil volume is large, which takes time and labor for excavation, and it is desired to reduce the cost and shorten the construction period. It is the current situation.

[0004] In view of such circumstances, the present inventors cut the buried pipe in advance from the inside and excavate the ground so that only the upper half of the buried pipe is exposed, thereby reducing the amount of excavated soil. We are developing a construction method.

[0005]

However, the following problems have arisen in the development of the above-mentioned construction method. That is, a plasma arc cutting machine is used for cutting from the inside of the buried pipe in the method, but as is well known, the plasma arc cutting machine includes a torch provided in the cutting machine,
The cutting is performed by generating an arc between the base material (object to be cut). However, as shown in FIG. 9, in a buried pipe 1 used for a water pipe, a pipe main body 2 is made of cast iron, ductile cast iron, steel or the like, and its inner peripheral surface is lined with mortar, paint, or the like. 3 may be given. The mortar or the coating is a non-conductive material, and the buried pipe 1 having such a lining 3 cannot cut off the buried pipe 1 as it is because an arc cannot be generated between the torch and the lining 3. Can not do. For this reason, in order to cut the buried pipe 1, it is necessary to cut the lining 3 with a cutting machine 5 or the like to expose the pipe main body 2, which requires extra labor and hinders shortening of the construction period. In addition, since the cutting operation is performed in a narrow space, there is a problem that the operation is also troublesome for the operator.

SUMMARY OF THE INVENTION The present invention has been made in view of the above points, and can easily and reliably cut a pipe having a lining, thereby contributing to shortening of a construction period and cost reduction. It is an object of the present invention to provide a pipe cutting method capable of cutting and a cutting machine used therein.

[0007]

The invention according to claim 1 is
When cutting a tube whose main body is made of a conductive material and whose inner peripheral surface is covered with a lining made of a non-conductive material, a movable plasma arc type cutting machine is inserted into the tube, and the cutting is performed. Cutting the tube by generating a plasma arc between the torch and the conductor while a conductor made of a conductive material is interposed between the torch of the machine and the lining of the tube. It is characterized by:

According to a second aspect of the present invention, in the tube cutting method according to the first aspect, the conductor is disposed along a position to be cut on an inner peripheral surface of the lining. .

According to a third aspect of the present invention, in the tube cutting method according to the first aspect, the conductor is provided only at a cutting start position of the inner peripheral surface of the lining by the cutting machine. And

According to a fourth aspect of the present invention, in the method for cutting a tubular body according to the third aspect, a strip-shaped conductor supplied in front of the torch as a conductor by a conductor supplying means provided on the torch. It is characterized by using a metal plate.

The invention according to claim 5 is a plasma arc type cutting machine for cutting a tube whose main body is made of a conductive material and whose inner peripheral surface is covered with a lining made of a non-conductive material. In addition, a conductor supply mechanism for continuously supplying a strip-shaped conductor is provided in front of a torch for generating a plasma arc.

[0012]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, first to third embodiments of a tube cutting method and a cutting machine used in the present invention will be described with reference to FIGS.

[First Embodiment] First, an example in which a conductor is arranged at a position to be cut on the inner peripheral surface of a lining will be described here.

In FIGS. 1 and 2, reference numeral 1 denotes a buried pipe (pipe) for water supply or sewerage which needs to be removed from the ground due to deterioration or the like. This buried pipe 1
The pipe body (body) 2 itself is made of a conductive material such as cast iron, ductile cast iron, and steel, and a lining 3 made of a non-conductive material such as mortar or paint is provided on the entire inner peripheral surface to prevent corrosion. Is applied over a predetermined thickness.

In order to remove such a buried pipe 1, first, as shown in FIG. 1, at both ends (only one end is shown in the figure) of a section where removal of the buried pipe 1 is required. After the ground G is subjected to the earth retaining work 12, the inside thereof is excavated to form the shaft 13, and the buried pipe 1 exposed in the shaft 13 is removed.

Next, the buried pipe 1 facing the inner surface of the shaft 13
As shown in FIG. 2, a conductor 14 made of a conductive material such as an iron plate, which has been previously processed into a circular or semicircular shape in accordance with the inner diameter of the buried pipe 1, is inserted into the buried pipe 1 from the end of the , And the conductors 14 are attached to the inner peripheral surface of the lining 3 of the buried pipe 1 at positions to be cut.

Then, as shown in FIG. 1, a plasma generator 15, a controller 16, a compressor 17 and the like are installed around the shaft 13, and a cutting machine 18 is inserted from the end of the buried pipe 1 into the inside.

As shown in FIG. 1 and FIG.
Numeral 8 denotes a plasma arc type, in which a torch 19 is provided on a truck 18a which can move and move in the buried pipe 1, and as a working gas for converting the arc into plasma, for example, FIG.
Plasma generator 15 and compressor 17 shown in FIG.
And a mixed gas of argon and hydrogen supplied from the company. Then, an arc (air discharge) is generated between an electrode (cathode) (not shown) provided on the torch 19 and a base material (anode) to be cut, and a working gas is jetted there to generate a plasma. The base material is cut by ejecting the plasma arc (plasma beam) in the high temperature state from the torch 19.

As shown in FIG. 3, the torch 19 is rotatable in a horizontal plane and a vertical plane by rotating mechanisms 20a and 20b. And, as shown in FIG.
The operations of the carriage 18a and the torch 19 of the cutting machine 18 are remotely controlled by the controller 16.

As shown in FIG. 2, in the cutting machine 18 placed at a predetermined position in the buried pipe 1, the conductor 1 made of an electrode of a torch 19 and an iron plate or the like adhered to the inner peripheral surface of the lining 3 is used.
4 by generating an arc with the conductor 1
Cut 4 Then, the plasma arc that has cut the conductor 14 cuts the lining 3 and the tube main body 2 with the momentum. Furthermore, by rotating the torch 19 of the cutting machine 18 in the circumferential direction of the buried pipe 1, the conductor 14, the lining 3 and the pipe main body 2 are cut integrally in the circumferential direction.
Thus, the conductor 14 is located between the torch 14 and the buried pipe 1.
, The buried pipe 1 is cut.

Thereafter, every time the cutting machine 18 is moved by a predetermined dimension in the direction in which the buried pipe 1 extends, the torch 1
At 9, the buried pipe 1 is cut from the inside in the circumferential direction. In this way, the movement of the cutting machine 18 by a predetermined size and the cutting of the buried pipe 1 by the torch 19 are repeated over the entire length of the section where the buried pipe 1 is to be removed. Thereby, the buried pipe 1
Are cut at predetermined length-wise dimensions to form a so-called sliced state.

After the above cutting work of the buried pipe 1 is completed, sheet piles (not shown) for retaining are installed at predetermined intervals on both sides of the buried pipe 1, and the ground G between these sheet piles (not shown) is removed.
Excavation is performed until the upper half of the buried pipe 1 is exposed. Subsequently, the cut buried pipes 1 are lifted one by one by a crane, for example, and dug out and removed. Thereafter, laying of a new pipe or the like is performed as necessary, and the space between the shaft 13 (see FIG. 1) and the sheet pile (not shown) is backfilled, whereby the removal of the buried pipe 1 is completed.

In the cutting method for the buried pipe 1 described above, a cutting machine 18 is inserted into the buried pipe 1, a conductor 14 made of an iron plate or the like is attached to the inner peripheral surface of the lining 3, and a torch 19 and the lining 3 of the buried pipe 1 are attached. In this state, the buried tube 1 is cut by generating a plasma arc between the torch 19 and the conductor 14 with the conductor 14 interposed therebetween. This eliminates the need to cut the lining 3 when cutting the buried pipe 1, thereby simplifying the work, shortening the work period and reducing the work cost, and eliminating the troublesome work for the worker. Environment and work safety can be improved.

Further, by cutting the buried pipe 1 from the inside by the cutting machine 18 placed in the buried pipe 1, it is not necessary to cut the buried pipe 1 from the outside as in the conventional case. This eliminates the need for a space for an operator to enter the side of the buried pipe 1, thereby reducing the interval between sheet piles (not shown), that is, the excavation width, and exposing only the upper half of the buried pipe 1. Since it is good, the excavation depth can be reduced. Therefore, the amount of excavated soil can be significantly reduced as compared with the conventional art, and the cost and time required for the operation can be reduced. Further, since the buried pipe 1 is cut into a ring by the cutting machine 18, the shape of the buried pipe 1 is maintained until cutting starts after cutting the buried pipe 1,
The ground G on the buried pipe 1 does not collapse. Therefore, there is no need to block traffic or traffic and provide a lining plate until the start of excavation.As a result, the time from excavation to backfilling can be shortened to the minimum, thus shortening the construction period. It is possible to minimize the influence on surrounding traffic and traffic.
Further, since it is not necessary for the worker to enter a narrow place below the ground surface to perform the work, the safety of the work can be improved.

In the first embodiment, the conductor 14 does not matter at all if it is a conductive material. If the lining 3 is to be covered by the cutting machine 18, the conductor 14 is not limited to a circular or semicircular shape, but may be a further divided shape or the like. Not something.

[Second Embodiment] Next, an example in which a conductor is provided only at a cutting start position by a plasma arc cutting machine will be described. In the second embodiment described below, only the method of cutting the buried pipe is different from that of the first embodiment, and the entire configuration for removing the buried pipe 1 is common. The same components as those in the first embodiment are denoted by the same reference numerals, and description thereof is omitted.

In order to remove the buried pipe 1, first, as shown in FIG. 1, a plasma arc type cutting machine 1 is inserted into the buried pipe 1 from a shaft 13 formed at the end of the buried pipe 1 to be removed.
8 is moved to a predetermined position to be cut.

Then, as shown in FIGS. 4 and 5, on the lining 3 at the position where cutting is to be started by the cutting machine 18,
An ignition body (conductor) 21 is provided. This igniter 21 is
For example, it has a predetermined size made of a conductive material such as iron. As shown in FIG. 5, both the igniter 21 and the tube body 2 are grounded 22 and 23.

Next, as shown in FIG. 5A, the torch 19 of the cutting machine 18 is made to face the igniter 21 and
A plasma arc is generated between the fuel and the igniter 21. As shown in FIG. 5 (b), this plasma arc
5, the lining 3 is cut and the pipe main body 2 starts to be cut with the momentum as shown in FIG. 5 (c). Then, in this state, the pipe body 2 made of a conductive material
Is exposed, so that the pipe body 2 and the torch 19
And the plasma arc is maintained between them. Subsequently, as shown in FIG. 5D, the torch 19 is rotated in the circumferential direction of the buried pipe 1 so that the buried pipe 1 is cut by a plasma arc.

Thereafter, each time the cutting machine 18 is moved by a predetermined dimension in the direction in which the buried pipe 1 extends, the igniter 21 is installed at the cutting start position, from which the buried pipe 1 is rotated from the inside by the torch 19. By cutting in the direction, the buried pipe 1 is sliced every predetermined length. After the cutting operation of the buried pipe 1 was completed, the ground G (see FIG. 1) was excavated and cut until the upper half of the buried pipe 1 was exposed in the same manner as in the first embodiment. The buried pipes 1 are lifted one by one by a crane or the like, and are dug out and removed. Thereafter, laying of a new pipe or the like is performed as necessary, and the space between the shaft 13 (see FIG. 1) and the sheet pile (not shown) is backfilled, whereby the removal of the buried pipe 1 is completed.

In the cutting method for the buried pipe 1 described above, the igniter 21 is installed only at the cutting start position of the cutting machine 18. Thus, if the cutting is started by the cutting machine 18 and the igniter 21 is cut, the tube body 2 covered with the lining 3 can be exposed by the force of the plasma arc. The buried pipe 1 can be cut by holding the plasma arc between them. Therefore, as in the first embodiment, it is not necessary to cut the lining 3 when cutting the buried pipe 1.
The work can be simplified, the work period and work cost can be reduced, and the work environment and work safety can be improved. Moreover, compared to the first embodiment, the size of the igniter 21 can be as small as possible to hold the plasma arc until the tube 2 is exposed, and can be realized at lower cost. Also, the setting of the igniter 21 can be easily performed without any trouble.

In the second embodiment, the material, width and thickness of the igniter 21 are not limited at all, and the material of the lining 3 is set so that the plasma arc can be held until the tube body 2 is exposed. What is necessary is just to set suitably according to thickness and thickness.

[Third Embodiment] Next, an example in which a strip-shaped metal plate continuously supplied in front of a torch is used as a conductor will be described. In the third embodiment described below, the biggest feature is that the configuration of the cutting machine used is different from the first and second embodiments, and the same reference numerals are used for common configurations. And description thereof is omitted.

Here, a cutting machine used for cutting the buried pipe 1 will be described first. As shown in FIG.
Is a cutting machine 1 according to the first and second embodiments.
8 (see FIG. 2), the basic configuration is the same.
A torch 19 that generates a plasma arc is provided on a carriage 30a that can travel inside the vehicle. As shown in FIG. 7, the torch 19 is provided so as to be rotatable in a horizontal plane and a vertical plane by rotating mechanisms 20a and 20b. Then, as shown in FIG. 1, the operations of the carriage 30a and the torch 19 are remotely controlled by the controller 16.

As shown in FIG. 6 and FIG.
Is provided with a conductor supply mechanism 31 in front of the torch 19 in the arc generation direction. The conductor supply mechanism 31 includes a feeding roller 33 on which a thin band-shaped (tape-shaped) conductor 32 made of a conductive metal is wound, and a winding roller 34 for winding the conductor 32 fed from the feeding roller 33. Guide rollers 35 and 3 for guiding the conductor 32 fed from the feed roller 33 to the front of the torch 19.
6 is comprised. The conductor supply mechanism 31 can be wound up by the take-up roller 34 while automatically feeding out the conductor 32 from the feed-out roller 33 by remotely operating the controller 16 (see FIG. 1). ing.

In order to remove the buried pipe 1 using such a cutting machine 30, first, as shown in FIG. 1, the buried pipe 1 is removed from the shaft 13 formed at the end of the buried pipe 1 to be removed. The cutting machine 30 of the plasma arc type is put in the inside, and is moved to a predetermined position to be cut.

Then, as shown in FIG. 8A, a plasma arc is generated between the torch 19 of the cutting machine 30 and the conductor 32 fed out of the torch 19 by the conductor supply mechanism 31. Then, as in the second embodiment, as shown in FIG. 8B, the plasma arc cuts the conductor 32, and furthermore, the plasma arc cuts the lining 3 as shown in FIG. 8C. Cut and start cutting the tube body 2. At this time, if the conductor 32 is continuously fed out from the feed roller 33 by the conductor supply mechanism 31, the plasma arc is generated between the conductor 32 and the torch 19 until the lining 3 is cut and the tube body 2 is exposed. And is held between. Then, FIG.
When the tube body 2 is exposed, a plasma arc is held between the tube body 2 and the torch 19, and thereafter, the torch 19 is rotated in the circumferential direction of the buried tube 1. Thus, the buried pipe 1 is cut in a circle.

Thereafter, every time the cutting machine 30 is moved by a predetermined dimension in the direction in which the buried pipe 1 extends, in the same manner as described above,
At that position, the buried pipe 1 is cut from the inside in the circumferential direction by the torch 19, and the buried pipe 1 is cut in a predetermined lengthwise direction. After the cutting operation of the buried pipe 1 is completed, the ground G is excavated until the upper half of the buried pipe 1 is exposed in the same manner as in the first embodiment, and the cut buried pipe 1 is cut, for example. Lift them one by one with a crane, etc. and remove them. Thereafter, laying of a new pipe or the like is performed as necessary, and the space between the shaft 13 (see FIG. 1) and the sheet pile (not shown) is backfilled, whereby the removal of the buried pipe 1 is completed.

As described above, in the method of cutting the buried pipe 1 and the cutting machine 30 used for the same, the torch 19 is provided with the conductor supply mechanism 31. To the torch 1
9 and is provided between the buried pipe 1 and the feed pipe 9. Thus, as in the second embodiment, if the cutting is started by the cutting machine 30 to cut the conductor 32, the tube body 2 covered with the lining 3 is exposed by the force of the plasma arc. After that, this pipe body 2
The buried pipe 1 can be cut while maintaining the plasma arc between the buried pipe 1 and the base. Therefore, it is not necessary to cut the lining 3 in cutting the buried pipe 1, so that the work can be simplified, the work period and work cost can be reduced, and the work environment and work safety can be improved. it can. In addition, since the conductors 32 can be continuously supplied, there is no need to set the igniter 21 as in the second embodiment, and the work efficiency can be further improved. Furthermore, since the plasma arc can be freely held while the conductor 32 is continuously supplied, it is possible to easily cope with the case where the lining 3 is partially thick or the like.

In the third embodiment, the configuration of the conductor supply mechanism 31 is not limited as long as the conductor 32 can be supplied continuously.

As for the configuration described in the first to third embodiments, any configuration may be employed without departing from the gist of the present invention. For example,
Although the torch 19 is configured to be rotatable in a horizontal plane and a vertical plane, the invention is not limited to this, and any structure may be used. Further, the buried pipe 1 is configured to be sliced in the circumferential direction by the torch 19, but the cutting direction and the like are not limited at all. For example, the buried pipe 1 is divided into a plurality of pieces in the circumferential direction by cutting along the direction in which the buried pipe 1 is continuous, and without removing the pipe, a wedge-shaped member is pushed inward and the divided pipe is pushed into the surrounding ground. ,
The present invention can be applied to a so-called propulsion method in which a new pipe is inserted and installed in the space inside thereof, and in such a case, the same effect as described above can be obtained. In addition, there is no intention to limit the cross-sectional shape, material, use, and the like of the buried pipe 1 at all. For example, the buried pipe 1 may have a rectangular cross section. In addition, the pipe body to which the pipe body cutting method according to the present invention and the cutting machine used therefor are applied are not limited to those buried underground as long as they are cut from the inside.

Other than this, any configuration may be adopted as long as it does not depart from the gist of the present invention, and it is needless to say that the above-described configurations may be appropriately selectively combined. No.

[0043]

As described above, according to the tube cutting method according to the first aspect, a plasma arc type cutting machine is inserted into the tube, and the space between the torch of the cutting machine and the lining of the tube is inserted. The tube is cut by generating a plasma arc between the torch and the conductor with the conductor interposed therebetween. According to the pipe body cutting method of the second aspect, the conductor is arranged along the position to be cut on the inner peripheral surface of the lining. This eliminates the need to cut the lining when cutting the pipe, thereby simplifying the work and shortening the work period and cost.Furthermore, the work environment and Work safety can be improved.

According to the pipe cutting method of the third aspect,
The conductor is arranged only at the cutting start position on the inner peripheral surface of the lining. Thereby, while cutting the conductor, it is possible to expose the main body made of a conductive material by cutting the lining with the force of the plasma arc,
Thereafter, the tube can be cut while holding the plasma arc with the main body. Therefore, the size of the conductor is the minimum required to hold the plasma arc until the main body is exposed, and it can be realized at lower cost. In addition, the conductor can be easily installed without trouble. Can be.

According to the pipe cutting method of the fourth aspect,
As the conductor, a band-shaped metal plate supplied in front of the torch by a conductor supplying means provided in the torch is used. Thereby, since the conductor can be continuously supplied, there is no need to set the conductor every time cutting is performed,
It is possible to further improve work efficiency. Furthermore, if the conductor is continuously supplied, the plasma arc can be freely held during that time, so that it is possible to easily cope with the case where the lining is partially thick or the like.

According to the cutting machine of the fifth aspect, a conductor supply mechanism for continuously supplying a strip-shaped conductor is provided in front of the torch for generating a plasma arc. Thereby, the pipe cutting method according to claim 4 can be realized, and the work efficiency can be improved. In addition, if the conductor is continuously supplied, the plasma arc can be freely held during that time, so that the cutting can be performed regardless of the thickness of the lining, and this cutting machine is extremely versatile. be able to.

[Brief description of the drawings]

FIG. 1 is a side sectional view showing first and third embodiments of a pipe body cutting method according to the present invention and a cutting machine used therefor.

FIG. 2 is an elevational sectional view showing a first embodiment of the pipe cutting method.

FIG. 3 is a side view showing a part of a cutting machine used in the method.

FIG. 4 is an elevational sectional view showing a second embodiment of the pipe cutting method.

FIG. 5 is a view showing a process of cutting a pipe body in the same method.

FIG. 6 is an elevational sectional view showing a third embodiment of the pipe cutting method.

FIG. 7 is a side view showing a part of the cutting machine according to the present invention.

FIG. 8 is a view showing a process of cutting a pipe body in the method.

FIG. 9 is an elevational sectional view showing a conventional pipe cutting method.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 buried pipe (tube) 2 pipe main body (body) 3 lining 14, 32 conductor 18, 30 cutting machine 19 torch 21 igniter (conductor)

Claims (5)

[Claims] 1. A plasma arc type cutting machine which is movable into a tubular body whose main body is made of a conductive material and whose inner peripheral surface is cut by a lining covered with a lining made of a non-conductive material. In the state where a conductor made of a conductive material is interposed between the torch of the cutting machine and the lining of the tube body, by generating a plasma arc between the torch and the conductor, A pipe cutting method characterized by cutting a pipe. 2. The method for cutting a tubular body according to claim 1, wherein the conductor is disposed along a position to be cut on an inner peripheral surface of the lining. 3. The method for cutting a pipe according to claim 1, wherein the conductor is disposed only at a cutting start position of the inner peripheral surface of the lining by the cutting machine. Construction method. 4. The method for cutting a tubular body according to claim 3, wherein a strip-shaped metal plate supplied in front of the torch by a conductor supply means provided on the torch is used as the conductor. Characteristic tube cutting method. 5. A cutting machine of a plasma arc type for cutting a tube whose main body is made of a conductive material and whose inner peripheral surface is covered with a lining made of a non-conductive material, wherein a plasma arc is generated. A cutting machine comprising a conductor supplying mechanism for continuously supplying a belt-shaped conductor in front of a torch.