JPH0979424A - New pipe line construction technique in existing pipe line - Google Patents

Abstract

PROBLEM TO BE SOLVED: To weld seam part while restoring a shape of a metallic pipe from convolved-shape to circular shape manufactured initially and to reduce the trouble and time for jointing with welding by inserting continuously into an existing pipe line which opens in a work pit a convolved-shape metallic pipe of its outside diameter reduced and forcedly passing through the pipe a pipe enlarging apparatus mounted with an automatic welding machine. SOLUTION: A steel pipe 5 is inserted from a work pit 2 into an existing pipe line 6 which opens in the pit 2, for example, by a drawing-in of a pull rope 8 resulting from actuation of winch 7 in the condition of convolved-shape, that is, of the outside diameter reduced. To restore a shape of a convolved-shape pipe 5' and weld a seam part, a pipe enlarging apparatus 10 mounted with an automatic welding machine 9 is passing forcedly through the steel pipe 5', for example, by the drawing-in operation of the pull rope 8 resulting from actuation of winch 7. The automatic welding machine 9 welds both edge parts. Thereby, a new pipe line which consists of the steel pipe 5 can be constructed in an existing pipe line.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of laying a new pipeline in an existing pipeline.

[0002]

2. Description of the Related Art Conventionally, as a method of laying a new pipeline in an existing pipeline, a new pipe (steel tube) of a fixed length is added by applying welding means in a work pit formed by excavation in the middle of the existing pipeline. However, a method has been proposed in which the pipes are sequentially inserted into the existing pipe.

[0003]

However, according to the above-mentioned conventional method, it is necessary to add a new pipe of a standard length in the work pit by welding, and it takes time and time to add a new pipe, and The insertion was intermittent and the work efficiency was not very good. In addition, in such a pipe-in-pipe construction method, in order to allow smooth insertion, the fitting is inevitably loose, so there is a gap between the old and new pipelines,
It was troublesome to fill the gap with backfilling material such as cement milk.

The present invention has been made for the purpose of eliminating the problems of the conventional method.

[0005]

According to the present invention, when a new pipeline is laid in an existing pipeline, a metal plate winding coil is formed on the ground, and a pipe-making section and a pipe are deformed in a work pit for excavation formation on the ground. In the pipe making part, one unwelded seam parallel to the longitudinal direction of the pipe is provided by installing the work parts respectively and continuously supplying the metal plate from the coil to the pipe making part and the pipe deformation work part. A circular tubular metal pipe having a pipe is continuously produced so as to have an outer diameter substantially corresponding to the inner diameter of an existing pipeline, and in the pipe deformation processing portion, a joint portion of the metal pipe is formed. The outer diameter of the metal pipe is reduced by continuously deforming the edge so that it shifts in the pipe circumference direction, and the outer diameter of the metal pipe is reduced. Continuously insert into the existing pipeline, and after inserting, By forcibly passing a pipe expander equipped with an automatic welding machine into the rolled tubular metal pipe, the metal pipe is welded to the seam while the shape of the metal pipe is restored from the rolled pipe to the original circular pipe shape as the pipe expands. It relates to a new pipe laying method inside an existing pipeline, which is characterized in that

[0006]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of the present invention will be described below with reference to the accompanying drawings.

Although the steel pipe has been described in the embodiment, it may be an aluminum pipe, a stainless pipe or the like.

FIG. 1 schematically shows the entire process of inserting a steel pipe, which is the first step of the method of the present invention, in which a steel sheet winding coil 1 is provided on the ground, and a pipe forming portion is provided in a work pit 2 for excavation formation on the ground. 3 and a pipe deformation processing unit 4 are installed respectively.

In carrying out the former step, the steel sheet 1a is continuously supplied to the pipe-making section 3 while being drawn out from the coil 1.

For example, when the steel plate 1a is supplied with the steel plate 1a in the same manner as in the electric resistance welded pipe manufacturing process, the group of forming rolls 3a works to manufacture a circular tubular steel pipe 5 from the steel plate 1a. .

The steel pipe 5 is manufactured so as to have an outer diameter substantially the same as the inner diameter of the existing pipeline 6, and the manufactured steel pipe 5 is a single unwelded pipe parallel to the longitudinal direction of the pipe. Seam 5a (Fig. 2
Reference).

The steel pipe 5 produced in the pipe producing unit 3 is then sent to the pipe deformation processing unit 4, where it is deformed into a rolled pipe.

FIG. 2 shows the state of deformation processing in the pipe deformation processing portion 4, and the steel pipe 5 is gradually deformed from the circular pipe shown at the left end of FIG. 2 to the winding pipe shown at the right end. A processing roll (not shown) can be used for the deformation processing of each stage. At the left end of FIG. 2, the joint portion 5a is shown with a gap in between for easy understanding, but in reality, in this joint portion 5a, both edge portions 5a ₁ and 5a ₁ are in contact with each other with substantially no gap. .

The edge portions 5a ₁ and 5a ₁ of the seam portion 5a are displaced in the direction around the pipe due to the deformation processing into a wound tubular shape, and a lap portion 5a ₂ is formed between the edge portions 5a ₁ and 5a _1. The outer diameter of the steel pipe 5 is reduced accordingly.

The steel pipe 5 is wound in a tubular shape, and thus in a state where the outer diameter is reduced, from the work pit 2 into the existing pipe line 6 opening in the pit 2, for example, the pulling rope 8 by the operation of the winch 7 is operated. It is inserted by pulling in.

After the step of inserting the steel pipe shown in FIG. 1 is completed, in the subsequent step shown in FIG. 3, in order to restore the shape of the rolled tubular steel pipe 5'and weld the joint portion 5a, the steel pipe 5'is formed. A tube expander 10 having an automatic welding machine 9 mounted therein is forcibly passed by, for example, a pulling operation of a tow rope 8 by an operation of a winch 7.

The pipe expander 10 has an outer diameter substantially corresponding to the inner diameter of the steel pipe 5 at the beginning of pipe manufacturing, and pushes the rolled tubular steel pipe 5'from the inside to expand the lap portion 5a ₂ while the rolled tubular steel pipe 5'is passing through the pipe, thereby eliminating the steel pipe. Is restored from the wound tubular shape to the circular tubular shape at the beginning of pipe making, and both edge portions 5a ₁ and 5a ₁ are substantially abutted at the joint portion 5a.

On the other hand, the automatic welding machine 9 has two edge parts 5a ₁ ,
When 5a ₁ returns to the substantially abutting state, both edge portions 5a ₁ and 5a ₁ are welded so as to follow this.

Therefore, by completing the latter step, a new pipeline made of the steel pipe 5 can be installed in the existing pipeline.

[0020]

According to the construction method of the present invention, new pipelines can be continuously laid in the existing pipeline without any gaps, so that the number of welding steps and backfilling as seen in the conventional construction method can be reduced. This eliminates the need for labor and enables the new pipe laying work to be performed efficiently automatically and mechanically.

[Brief description of drawings]

FIG. 1 is an overall view schematically showing a situation of a former step of a method of the present invention.

FIG. 2 is an explanatory view schematically showing a deformation processing state of a steel pipe into a rolled pipe.

FIG. 3 is an overall view schematically showing a situation of a latter step of the method of the present invention.

FIG. 4 is an explanatory view schematically showing the shape restoration of a rolled tubular steel pipe and the state of automatic welding.

[Explanation of symbols]

 1 Steel Plate Winding Coil 2 Work Pit 3 Pipe Making Section 4 Pipe Deformation Processing Section 5 Steel Pipe 6 Existing Pipeline 7 Winch 8 Traction Rope 9 Automatic Welding Machine 10 Pipe Expander

Claims (1)

[Claims] 1. When laying a new pipeline in an existing pipeline, a metal plate winding coil is installed on the ground, and a pipe manufacturing section and a pipe deformation processing section are installed in a work pit for excavation formation on the ground, respectively.
By continuously supplying the metal plate from the coil to the pipe forming portion and the pipe deformation processing portion, a circular tubular metal pipe having one unwelded seam parallel to the pipe longitudinal direction is formed in the pipe forming portion. Pipes are continuously manufactured so that they have an outer diameter approximately equivalent to the inner diameter of the existing pipeline, and in the pipe deformation processing part,
The outer diameter of the metal pipe is reduced by continuously performing deformation processing so that both edges forming the seam portion of the metal pipe are displaced in the pipe circumferential direction, thereby reducing the outer diameter of the metal pipe. The metal tube should be continuously inserted into the existing pipeline that opens into the work pit, and after the insertion is completed, the tube expander equipped with an automatic welding machine should be forcedly passed through the wound tubular metal tube. The method of laying a new pipe in an existing pipeline is characterized in that the metal pipe is welded to a seam portion while the shape of the metal pipe is restored to a circular pipe shape at the beginning of pipe making as the pipe expands. .