JP2000130682A - Process of cutting existing pipe and process of inserting nonshut-off valve - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process of inserting nonshut-off valve having a low degree of reduction in strength in an existing pipe, a process of cutting an existing pipe, which is appropriate for the former process. SOLUTION: A process of cutting an existing pipe 1, includes an assembly step and a cutting step. At the assembly step, a part of the existing pipe 1 is hermetically surrounded by sealing casings 21, 22, 23, and a cutting tool 4 is accommodated in the sealing casing 21, 22, 23, and at the cutting step, the cutting tool 4 is rotated so as to carry out cutting while the sealing casings 21, 22, 23 are moved in the axial direction S of the pipe 1 so as to cut the existing pipe by means of the cutting tool 4 in order to form an opened linear groove 12C. After the cutting tool is taken out, a valve is inserted in the pipe.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an existing pipe cutting method and a method for inserting a non-disruptive valve.

[0002]

2. Description of the Related Art Conventionally, there is a well-known method of inserting a valve into a pipe including an existing pipe by inserting a valve into a hole of the existing pipe in a pipeline including the existing pipe. 516,598). As one of such methods, a method of inserting a valve as a line breaker is known.

[0003]

However, in the conventional method, since a circular hole close to the nominal diameter of the existing pipe is formed, there is a disadvantage that the strength of the existing pipe is greatly reduced.

[0004]

SUMMARY OF THE INVENTION Accordingly, it is an object of the present invention to provide a method of inserting an unbreakable valve in which the strength of an existing pipe is reduced little. Further, an essential object of the present invention is to provide an existing pipe cutting method suitable for the valve insertion method.

In order to achieve the above object, the existing pipe cutting method of the present invention includes an assembling step and a cutting step.
In the assembling step, a part of the existing pipe is hermetically surrounded by a plurality of sealed cases divided in the circumferential direction of the existing pipe, and is fixed to a rotatably supported cutter shaft and has a plurality of cuts. A cutting tool having a razor blade is housed in the closed case while being attached to the closed case. In the cutting step, the cutting tool is fed in the radial direction of the existing pipe while rotating the cutting tool about the cutter axis to perform a cutting motion for cutting the existing pipe by rotation of the cutting tool. At the same time, by moving the sealed case in the pipe axis direction of the existing pipe, the cutting tool is moved in the pipe axis direction to cause the cutting tool to perform a feeding motion, so that the existing pipe is left without leaving a section. Is cut by the cutting tool to form a cut-out linear groove in the existing pipe. After removing the tool, the valve is inserted into the pipe.

[0006]

According to the present invention, since a straight groove that is long in the pipe axis direction is formed in the existing pipe, the portion cut off in the circumferential direction is small, so that the reduction in strength of the existing pipe is reduced.

[0007]

[Definition] In the present invention, the term "existing pipe" means a pipe in which a fluid such as water flows, and is generally buried underground. The term "sealed" does not mean completely closed, but means to maintain watertightness enough for construction without interruption. Therefore, the “sealed case” refers to a case having a pressure resistance capable of withstanding the pressure of the fluid flowing in the existing pipe and a certain degree of water stopping performance. Further, "surrounding in an airtight state" means cutting or sealing to such an extent that it does not interfere with operations such as valve insertion after cutting.For example, a drain port is provided in the sealed case, The drain may be opened during cutting, and chips may be discharged together with water from the drain.

Since the "cutting tool" used in the present method has a plurality of cutting blades, the cutting tool includes a cutting tool and a cutter wheel having a single continuous cutting blade. Not. Here, in the present specification, “pillar shape”
In addition to the cylinder, the shape includes a truncated cone, a shape obtained by adding a cone to a cylinder, and a conical shape. Further, the cutting tool may have a column shape whose length is shorter than the outer diameter of the cutting tool. When cutting an existing pipe having a mortar lining on the inner surface of the pipe, a cutting tool provided with a large number of cutting blades (tips) made of cemented carbide or a cutting tool using diamond particles as the cutting blade is used. It is preferably used.

[0009] In the present invention, "cutting" refers to cutting a part of a pipe wall by rotating a plurality of cutting blades. In addition, the `` cutting motion '' refers to rotating a plurality of cutting blades, while the `` feeding motion '' refers to a position where a new portion of a pipe wall can be cut one after another by the cutting tool. Moving the cutting tool.

In the present invention, "inserting a valve (into a pipe line)" does not mean that a valve or a valve body is physically inserted into a cut and removed portion of an existing pipe. Refers to installing a valve in the pipeline to control the water stoppage or flow rate of the pipeline.

[0011]

DESCRIPTION OF THE PREFERRED EMBODIMENTS One embodiment of the present invention will be described below with reference to the drawings. The sealed case 2 is composed of a first and a second divided into two parts in the circumferential direction.
It has split cases 21 and 22 and a cutter case 23. Packing insertion portions 25 into which the rubber ring 24 shown in FIG. During construction, water is stopped by another rubber ring 26.

The second split case 21 has a branch portion 27 which projects radially outward of the existing pipe 1 in a branch shape. The cutter case 23 shown in FIG. 2 is fixed to the flange 27a of the branch portion 27.

[0013] The cutting device 3 in the cutter case 23, the worm gear (drive gear) 30 is accommodated. The worm gear 30 is connected to a motor such as a motor provided outside the cutter case 23, and rotates the worm wheel 31 by the power of the motor. The worm wheel 31 is engaged with a cutter shaft 32 in a rotational direction, and a cutting tool 4 similar to an end mill is fixed to a tip portion of the cutter shaft 32.
Therefore, the cutting tool 4 is driven by the power of
Rotate around 2.

On the other hand, the cutter shaft 32 is slidably provided in the radial direction C of the existing pipe 1 with respect to the worm wheel 31. A male feed screw 34 is in contact with the upper end of the cutter shaft 32 via a steel ball 33. Therefore,
The cutting tool 4 can be fed in the radial direction C of the existing pipe 1 by screwing the feed male screw 34 in the radial direction (cutting direction) C.

The cutting tool 4 has a large number of cutting blades 42 on the distal end surface 40 and the outer peripheral surface 41 of a substantially column. The cutting tool 4 is housed in the branched portion 27 of the closed case 2. In addition, it is preferable that the cutting tool 4 has its tip sharpened in a cone shape.

Next, the method of construction will be described. 1. Assembling Step First, with the fluid (water) flowing in the existing pipe 1 of FIG. 1, the sealed case 2 is attached to the existing pipe 1, and the two split cases 21 and 22 are assembled by an unillustrated assembling bolt. After that, the cutter case 23 is attached to the closed case 2. Thus, the sealed case 2 surrounds the existing pipe 1 in an airtight state.

Next, a pair of split wheels 5 and positioning spacers 50 are mounted at positions away from both sides of the sealed case 2. The split ring 5 is fixed to the existing pipe 1 by a set screw (not shown). The positioning spacer 50 determines the fixing position according to the length of the groove to be cut. A feed screw 51 for moving the sealed case 2 in the tube axis direction S is attached to the split ring 5. One end of the feed screw 51 is rotatably engaged with an end of the closed case 2 via an engaging member 52. Therefore, by rotating the feed screw 51 counterclockwise, the sealed case 2 moves to the left, while rotating the feed screw 51 clockwise moves the sealed case 2 to the right.

Cutting Step After the assembling step, when an operator drives a motor (not shown), the cutting tool 4 rotates together with the cutter shaft 32 and starts a cutting motion for cutting the existing pipe 1. While the cutting motion is being performed, when the operator drives the feed male screw 34 shown in FIG. 2 in the radial direction C, the distal end face 40 of the cutting tool 4 eventually becomes as shown in FIG. Through a part of the pipe wall 1a of the existing pipe 1 toward the center of the pipe. Thereby, the cutting by the cutting tool 4 is completed. When the feed screw 51 is rotated counterclockwise after this cutting, the closed case 2 moves to the left in the pipe axis direction S, and along with this movement, the cutting tool 4 performs a feed motion for cutting the pipe wall 1a. Thereby, as shown in FIG.
In the existing pipe 1, a straight cutting groove 12C long in the pipe axis direction S is cut open without leaving a section.

The tool removal step Subsequently, by the following method, to remove the cutting device 3. First, as shown in FIG. 5, the feed screw 51 is rotated clockwise to return the cutting tool 4 to the center position of the cutting groove 12C. Thereafter, the butterfly valve 8 of FIG. 8 is inserted into the pipe 1A in place of the cutting device 3 by a known method. That is, FIG.
The work isolation valve 70 shown in FIG.
7a, and a work tank 71 is bonded on the work gate valve 70. After this joining, the working shaft 72 is pulled up, the cutting device 3 is housed in the working tank 71, and the working gate valve 70 is closed. After this, FIG.
After the butterfly valve 8 is accommodated in the work tank 71 shown in FIG. 7A, the work partition valve 70 shown in FIG. 7B is opened, and after the valve is opened, the work shaft 72 is lowered to make the butterfly valve 8 open.
Into the conduit 1A.

As shown in FIGS. 8 and 9, the butterfly valve 8 is inserted in an open state. In addition, sealed case 2
The rubber ring 24 is pushed into the packing insertion portion 25, and the split ring 5 is attached to the sealed case 2.

Next, the structure of the butterfly valve 8 will be described. The butterfly valve 8 of FIG. 9 includes a valve body 8a, a valve lid 8b, and a valve stem 8c. The closed case 2 constitutes a valve box of the butterfly valve 8. The valve lid 8b is fixed to the flange 27a of the split case 22. The valve lid 8b
Is integrally formed with a support cylinder 8d for rotatably supporting the valve rod 8c and a closing lid 8e. A rubber packing 8f is integrally fixed to the closing lid 8e, and the cutting groove 12C is closed by the rubber packing 8f. A reducer (not shown) connected to the valve rod 8c is mounted on the valve lid 8b. By rotating the valve rod 8c through 90 ° through the speed reducer, as shown in FIG.
a rotates 90 °, and the rubber lining 8g of the valve body 8a
By pressing against the inner peripheral surface of the existing pipe 1, the existing pipe 1 can be closed.

In the above embodiment, the butterfly valve 8 is inserted in place of the cutting tool 4, but in the present invention, the butterfly valve 8 and the cutting tool 4 are housed in the closed case 2 in advance, and after the cutting, By rotating the sealed case 2,
The butterfly valve 8 may be moved to the position of the cutting groove 12C.

As described above, the preferred embodiment has been described with reference to the drawings. However, those skilled in the art can easily envisage various changes and modifications within the obvious scope by referring to the present specification. There will be. For example, an engine may be used in addition to a motor as a prime mover for giving a cutting motion to a cutting tool. Alternatively, the prime mover may be installed on the ground, and the power of the prime mover may be transmitted to the cutting tool via a cutter shaft by a flexible shaft. After the existing pipe is surrounded by the sealed case, a cutting tool may be attached to the sealed case. Furthermore, after cutting the existing pipe 1, a branch pipe may be connected to the closed case via a gate valve. In the present invention, a disk-shaped cutting tool such as a diamond wheel may be used instead of the end mill-shaped cutting tool.

The number of sealed cases is three to four in the circumferential direction.
It may be divided into two. Further, the valve body may be inserted from any direction such as above, side, or below. Further, the present invention can be applied to gas pipes as well as water pipes.
That is, the fluid flowing through the existing pipe is not limited to water but may be another fluid such as gas or oil, which is included in the scope of the present invention.
Accordingly, such changes and modifications are to be construed as being within the scope of the invention as defined by the appended claims.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a state in which a sealed case is attached according to an embodiment of a method for inserting a non-disruptive valve according to the present invention.

FIG. 2 is a longitudinal sectional view showing a cutting device.

FIG. 3 is a longitudinal sectional view showing a cut state.

FIG. 4 is a longitudinal sectional view showing a state where cutting is completed.

FIG. 5 is a longitudinal sectional view showing a state in which the closed case is positioned.

FIG. 6 is a schematic process diagram showing a tool removal process.

FIG. 7 is a schematic process diagram illustrating a process of inserting a butterfly valve.

FIG. 8 is a longitudinal sectional view showing a state where a butterfly valve is inserted.

FIG. 9 is a cross-sectional view showing a state where a butterfly valve is inserted.

FIG. 10 is a vertical cross-sectional view showing a closed state of the butterfly valve.

[Explanation of symbols]

 1: Existing pipe 1a: Pipe wall 1A: Pipe line 1A 12C: Cutting groove 2: Sealed case 32: Cutter shaft 4: Cutting tool 40: Tip surface 41: Outer peripheral surface 42: Cutting blade 70: Working gate valve 8: Butterfly valve C: Radial direction S: Pipe axis direction

Claims (6)

[Claims] 1. An existing pipe cutting method comprising an assembling step and a cutting step, wherein in the assembling step, a part of the existing pipe is hermetically sealed by a closed case divided into a plurality of pieces in the circumferential direction of the existing pipe. Along with surrounding in a state, a cutting tool fixed to a rotatably supported cutter shaft and having a plurality of cutting blades is housed in the closed case while being mounted in the closed case, and in the cutting step, While rotating the cutting tool around the cutter axis to perform a cutting motion for cutting the existing pipe by the rotation of the cutting tool, the cutting tool is sent in a radial direction of the existing pipe, and the sealing is performed. By moving the case in the pipe axis direction of the existing pipe, by moving the cutting tool in the pipe axis direction and causing the cutting tool to perform a feed motion, the existing pipe can be cut by the cutting tool without leaving a section. Existing pipe cutting method which is cut to form a linear groove cut open the existing pipe by. 2. The cutting step according to claim 1, wherein after the cutting tool is sent toward a center in a radial direction of the existing pipe to a position where the cutting tool penetrates a part of a pipe wall of the existing pipe. An existing pipe cutting method for causing the cutting tool to perform the feed motion while performing the cutting motion in a state where the cutting tool penetrates the pipe wall. 3. The existing pipe cutting method according to claim 1, wherein the cutting tool is a cutting tool having a plurality of the cutting blades on a tip end surface and an outer peripheral surface of a column. 4. The cutter according to claim 3, wherein an axis of the cutter shaft is set in a radial direction of the existing pipe.
An existing pipe cutting method in which the cutting tool performs the cutting motion by rotating around the axis set in a radial direction of the existing pipe. 5. A method for inserting a butterfly valve into a portion of a pipe corresponding to the cut and removed portion after cutting the existing tube without leaving a section by using the cutting tool according to claim 4. . 6. A method for inserting a valve into a position corresponding to a cutting position, comprising an assembling step, a cutting step, and a tool removing step, wherein in the assembling step, a part of an existing pipe is removed. A cutting tool, which is enclosed in a hermetically sealed state by a sealed case divided into a plurality of pieces in the circumferential direction of the existing pipe, is fixed to a rotatably supported cutter shaft, and has a plurality of cutting blades, is provided in the sealed case. In the cutting step, the cutting tool is rotated around the cutter axis to perform a cutting motion for cutting the existing pipe by rotating the cutting tool, and the cutting is performed. By moving the tool in the radial direction of the existing pipe and moving the sealed case in the axial direction of the existing pipe, the cutting tool is moved in the axial direction of the pipe and fed to the cutting tool. Is performed, the existing pipe is cut by the cutting tool without leaving a section, and a cut-out linear groove is formed.In the tool removal step, via the working valve, after the end of the cutting, A non-disruptive valve insertion method for removing the cutting tool from the sealed case.