JP2001116168A - Construction method for connecting pipe - Google Patents

Abstract

PROBLEM TO BE SOLVED: To connect a resin pipe to a different diameter pipe which differs in outside diameter from the resin pipe, at a low cost for connection. SOLUTION: A shaping tube member with an inside diameter approximately equal to the outside diameter of the different diameter pipe C differing in outside diameter from an existing pipe A is concentrically and freely detachably fixed to the end of the existing pipe, and after a folding pipe made from a thermoplastic resin, passed through the existing pipe and the tube member, is deformed by a heated pressurized fluid to increase in diameter, it is cooled in the deformed state in which its diameter is increased, so that the resin pipe B with an outside diameter approximately equal to the inside diameter of the existing pipe is formed inside the existing pipe and a resin pipe connection E with an outside diameter approximately equal to the outside diameter of the different diameter pipe is formed inside the tube member. The resin pipe connection exposed on removal of the tube member and the different diameter pipe are concentrically connected to each other by a pipe connector D.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of expanding a radially-folded thermoplastic resin-made folding tube inserted into an existing tube by using a heated and pressurized fluid supplied into the folding tube. Thereafter, cooling is performed in the expanded and deformed state, and a resin pipe having an outer diameter that is substantially the same as the inner diameter of the existing pipe is formed inside the existing pipe. The present invention relates to a pipe connection method for connecting a different diameter pipe having an outer diameter different from the diameter in a series by a pipe connector.

[0002]

2. Description of the Related Art In a conventional pipe connection method, as shown in FIG. 6, for example, a resin pipe B formed inside an existing pipe A and a thermoplastic resin different diameter pipe C are formed of a thermoplastic resin pipe. Connection D
, A pipe connector such as a reducer having a resin pipe connection end 20 corresponding to the outer diameter of the resin pipe B and a different diameter pipe connection end 21 corresponding to the outer diameter of the different diameter pipe C. D, the ends of the resin pipes A are inserted into the connection ends 20 for resin pipes, and are thermally fused to each other.
The resin tube B and the different-diameter pipe C are connected in series by a pipe connector D.

[0003]

For this reason, a pipe connector having a connecting end for a resin pipe corresponding to the outer diameter of the resin pipe and a connecting end for a different diameter pipe corresponding to the outer diameter of the different diameter pipe is provided. In addition, it is necessary to obtain each time according to the outer diameter of the resin pipe or the outer diameter of the different diameter pipe, and there is a disadvantage that the connection cost is increased. The present invention has been made in view of the above circumstances, and an object of the present invention is to make it possible to connect a resin pipe and a different-diameter pipe having an outer diameter different from the outer diameter of the resin pipe at a low connection cost.

[0004]

A feature of the invention according to claim 1 is that a folding pipe made of a thermoplastic resin, which is inserted into an existing pipe and is radially folded and deformed, is supplied to the inside of the folding pipe. After being expanded and deformed by the pressurized fluid, it is cooled in the expanded and deformed state, and inside the existing pipe, a resin pipe having an outer diameter substantially equal to the inner diameter of the existing pipe is formed. A pipe connection method in which a resin pipe and a different-diameter pipe having an outer diameter different from the outer diameter of the resin pipe are connected in series by a pipe connector, the diameter being substantially the same as the outer diameter of the different-diameter pipe. The shaping tubular member having the inner diameter of the above is detachably fixed to the end of the existing pipe, and the folded pipe inserted through the existing pipe and the tubular member is expanded and deformed by the heated pressurized fluid. Then, cooling is performed in the expanded and deformed state to form the resin pipe inside the existing pipe, and A resin pipe connection portion having an outer diameter substantially the same as the outer diameter of the different diameter pipe is formed inside, and the resin pipe connection portion and the different diameter pipe in which the cylindrical member is removed and exposed are formed. The point is that the pipes are connected in series. [Operation] The shaping tubular member is detachably fixed to the end of the existing pipe, and the folded pipe is inserted through the existing pipe and the tubular member, expanded and deformed by heating and pressurizing fluid, and then expanded. Cooling in the radially deformed state, forming a resin pipe inside the existing pipe, and forming a resin pipe connection portion having an outer diameter substantially equal to the outer diameter of the different diameter pipe inside the cylindrical member, The resin pipe connection part and the different diameter pipe, which are removed by exposing the member, are connected in series by a pipe connection body. [Effect] A resin pipe connection end corresponding to the outer diameter of the resin pipe,
A pipe connector having a connection end for a different diameter pipe corresponding to the outer diameter of a different diameter pipe can be obtained inside the existing pipe without having to obtain it each time according to the outer diameter of the resin pipe or the outer diameter of the different diameter pipe. The resin pipe connection part and the different diameter pipe that are integrally formed on the resin pipe can be connected in series by a pipe connector, so the connection cost between the resin pipe and the different diameter pipe with an outer diameter different from the outer diameter of the resin pipe is low. Can be connected.

A feature of the invention according to claim 2 is that the different diameter pipe has an outer diameter larger than the outer diameter of the resin pipe. [Operation] By using a shaping tubular member having an inner diameter larger than the outer diameter of the resin pipe formed inside the existing pipe, a resin pipe connection portion having an outer diameter larger than the outer diameter of the resin pipe is formed. Therefore, wrinkling is less likely to occur on the outer peripheral surface of the resin pipe connection portion than when a resin pipe connection portion having an outer diameter smaller than the outer diameter of the resin pipe is formed. [Effect] When the resin pipe connecting portion is inserted into the tubular pipe connecting body and the resin pipe is connected to the different diameter pipe, the outer peripheral surface of the resin pipe connecting portion is brought into close contact with the cylindrical inner surface of the pipe connecting body. It is easy to connect the resin pipe connection part and the pipe connection body in a state where fluid leakage hardly occurs.

A characteristic feature of the invention according to claim 3 is that a hard cylinder is fitted inside the resin pipe connecting portion after the folded pipe is formed by cooling in a state of being expanded and deformed. [Operation] The radial contraction of the resin pipe connecting portion formed by cooling the folded pipe in the expanded and deformed state can be restricted by the cylindrical body fitted inside. [Effect] It is possible to accurately form the resin pipe connecting portion with an outer diameter substantially equal to the outer diameter of the different diameter pipe.

[0007]

Embodiments of the present invention will be described below with reference to the drawings. In the drawings, portions denoted by the same reference numerals as those of the conventional example indicate the same or corresponding portions. FIG. 1 shows a polyethylene resin having a substantially same outer diameter as the existing pipe A inside a cast iron gas supply pipe (hereinafter referred to as an existing pipe) A buried underground. A resin tube B made of a plastic resin) is provided, and the resin tube B and a newly formed pipe C made of a polyethylene resin (an example of a thermoplastic resin) having an outer diameter larger than that of the existing tube A are provided. And a pipe connection structure in which a pipe connection D as a pipe connection body is connected and connected in a concentric series. The resin pipe B is formed inside the old pipe A to replace the old pipe A.
A resin pipe connection portion E having an outer diameter substantially the same as the outer diameter of the different diameter pipe C
Is exposed from the end of the existing pipe A, is integrally formed with the end of the resin pipe B, and the resin pipe connection portion E is coaxially inserted into one end of the pipe joint D, and is connected to the pipe joint D. Connected.

The pipe joint D is made of a polyethylene resin (an example of a thermoplastic resin) which can be thermally fused to the resin pipe B and the different diameter pipe C. A joint connecting portion 2 provided with a contact surface 1 that is closely fitted to the outer peripheral surface of the joint so as to be fitted in a concentric manner is formed into a tubular shape integrally formed on the left and right sides. A heating wire 3 as a body is buried near the contact surface 1. Then, the heating wires 3 corresponding to each of the contact surfaces 1 are connected in series,
Terminals 3a for supplying electricity to these heating wires 3 are protrudingly provided on the outer peripheral side of the joint connection portion 2, and the corresponding contact surface 1 is heated by Joule heat generated when the heating wire 3 is supplied with electricity. The outer peripheral surface of E and the outer peripheral surface of the different diameter tube C are heat-sealed over the entire circumference.

Hereinafter, a pipe connection method for concentrically connecting the resin pipe B and the different-diameter pipe C with a pipe joint D will be described with reference to FIGS. As shown in FIG. 3 (a), a starting pit F1 is excavated at an intermediate position of the existing pipe A, and a reaching pit F2 is excavated at an end point of the existing pipe A, and the pits F1, F
2, a steel shaping tubular member 4 having an inner diameter substantially the same as the outer diameter of the different-diameter pipe C is attached to the end of the existing pipe A that opens into the arrival pit F2. It is detachably fixed concentrically with bolts 5. As shown in FIGS. 2A and 2B, the cylindrical member 4 has connecting flanges 6 at both ends in the circumferential direction.
The half cylinder members 7 are detachably connected to each other by bolts and nuts 8 in the form of a cylinder, and one half of each half cylinder member 7 in the cylinder axis direction has an interval in the cylinder circumferential direction and the cylinder axis direction. By pressing the tips of the plurality of bolts 5 screwed across the outer tube A to the outer peripheral surface of the existing pipe A,
It is fixed to the existing pipe A concentrically.

Next, as shown in FIG. 3B, a folding tube 9 made of a polyethylene resin (an example of a thermoplastic resin) that has been folded and deformed in the radial direction is wound near the entrance of the starting pit F1. From the drum 10 and the winding side base of the folding tube 9, a steam supply pipe 11 is inserted inside the folding tube 9.
And a boiler 12 that supplies heated and pressurized steam as an example of a heated and pressurized fluid, and a winch 13 near the entrance of the arrival pit F2, and is inserted between the existing pipe A and the tubular member 4. One end of the towed wire W is connected to the feeding end of the folded tube 9, and the other end is connected to the winch 13. The end of the folding tube 9 on the feeding side is sealed in advance. The folded pipe 9 is formed by temporarily molding a resin pipe made of polyethylene resin having an outer diameter substantially the same as the inner diameter of the existing pipe A, and then heating and softening the resin pipe to form a heart-shaped cross section. It is folded and deformed in the radial direction.

Next, heating steam is fed into the folded tube 9 wound around the drum 10 and heated until the folded tube 9 is softened. Then, the winch 13 is driven to remove the softened folded tube 9. Wire W is pulled into existing pipe A,
As shown in FIG. 4 (c), it is inserted over the existing pipe A and the tubular member 4. Next, the starting pit F1 side of the folding tube 9 is cut, and the cut end is heated and softened by a burner or the like and expanded and deformed by a diameter expanding jig. As shown in FIG. A rubber closing member 15 to which the steam supply pipe 14 is connected is mounted, and the pressurized steam is supplied into the folded pipe 9 by the steam supply pipe 14 so that the folded pipe 9 follows the inner peripheral surface of the existing pipe A. After expanding and deforming the pipe, the resin is cooled in the expanded and deformed state to form the resin pipe B along the inner peripheral surface of the existing pipe A inside the existing pipe A, A resin tube connecting portion E having an outer diameter substantially equal to the outer diameter of the cylindrical member is formed inside the tubular member 4. Therefore, the resin tube connecting portion E is formed by forcibly expanding the folded tube 9 so that the outer diameter thereof becomes larger than the outer diameter of the resin tube before the folding deformation.

Then, the tubular member 4 is removed, and as shown in FIG. 5 (a), the resin pipe connecting portion E is exposed and unnecessary portions are cut off to form a steel tubular body 16 as a hard tubular body. Is fitted inside the resin pipe connection portion E. The tubular body 16 includes a tubular portion 17 fitted inside the resin tube connecting portion E, and a flange portion 18 in contact with an end surface of the resin tube connecting portion E. It is formed in an annular shape with a width smaller than the thickness.

Next, the front of the arrival pit F2 of the existing pipe A is cut and cut, and a different-diameter pipe C is newly buried concentrically with the resin pipe connection portion E, as shown in FIG. The pipe joint D previously inserted through the different diameter pipe C is slid and fitted so as to straddle the resin pipe connecting portion E and the different diameter pipe C. In addition, different diameter pipe C
The tubular body 16 is fitted to the inner side of the end portion, similarly to the resin pipe connection portion E. Next, by energizing the heating wire 3 for a predetermined time, each of the contact surfaces 1 is heated together with the outer peripheral surface of the resin pipe connection portion E and the outer peripheral surface of the different-diameter tube C, and the respective adhesive surfaces 1 of the pipe joint D are heated. The outer peripheral surface of the resin pipe connection portion E and the outer peripheral surface of the different-diameter tube C are heat-sealed airtightly.

At this time, the resin pipe connection portion E and the different-diameter pipe C are easily heated and deformed, and are easily shrunk and deformed in the radial direction during cooling. Since the cylindrical body 16 is also fitted to the inside of the end of the different-diameter pipe C, both the resin pipe connecting portion E and the different-diameter pipe C are hardly deformed, so that the heat welding can be reliably performed over the entire circumference. it can. Then, the fused portion is naturally cooled, and the resin pipe B and the different-diameter pipe C are connected in series in a concentric manner by a pipe joint D as shown in FIG.

[Other Embodiments] The pipe connection method according to the present invention may use a folded pipe reinforced with fibers or the like. 2. In the pipe connection method according to the present invention, the resin pipe connection portion and the different diameter pipe may be connected in series by a valve as a pipe connection body. 3. In the pipe connection method according to the present invention, the resin pipe connection portion and the metal different-diameter pipe may be connected in series by a pipe connection body. 4. The pipe connecting method according to the present invention forms a resin pipe connecting portion having an outer diameter smaller than the outer diameter of the resin pipe formed inside the existing pipe, and calculates the resin pipe connecting portion and the outer diameter of the resin pipe. May be connected in series with a different diameter pipe having a smaller outer diameter by a pipe connector. 5. In the pipe connection method according to the present invention, a folding pipe is inserted so as to protrude from an end of an existing pipe, and a shaping tubular member is attached to the protruding portion, so that the folding pipe extends over the existing pipe and the tubular member. May be inserted. 6. The pipe connection method according to the present invention includes, as an existing pipe, not only a gas supply pipe, but also a resin pipe formed inside an existing water pipe or a sewer pipe, and an outer diameter different from the outer diameter of the existing pipe. The different diameter pipes may be connected in series by a pipe connector. 7. The pipe connection method according to the present invention may use a folded tube made of a thermoplastic resin such as a vinyl chloride resin other than the polyethylene resin.

[Brief description of the drawings]

FIG. 1 is a longitudinal sectional view showing a pipe connection structure.

FIG. 2 is a longitudinal sectional view (a) and a front view (b) of a main part.

FIG. 3 is an explanatory view of a pipe connection method.

FIG. 4 is an explanatory view of a pipe connection method.

FIG. 5 is an explanatory view of a pipe connection method.

FIG. 6 is an explanatory view of a conventional pipe connection method.

[Explanation of symbols]

 4 Tube member 9 Folded tube 16 Tube A A Existing tube B Resin tube C Different diameter tube D Pipe connection E Resin pipe connection

Claims (3)

[Claims] 1. A radially folded thermoplastic resin-made folding tube inserted through an existing tube is expanded and deformed by a heated and pressurized fluid supplied into the folded tube, and then expanded. Cooling in a state, forming a resin pipe having an outer diameter substantially the same as the inner diameter of the existing pipe inside the existing pipe, wherein the outer diameter of the resin pipe is different from the outer diameter of the resin pipe. A pipe connecting method for connecting a series of different diameter pipes with a pipe connector, wherein a shaping tubular member having an inner diameter substantially the same as the outer diameter of the different diameter pipe, After being fixed to an end portion in a detachable manner, the folded pipe inserted through the existing pipe and the tubular member is expanded and deformed by the heating and pressurized fluid, and then cooled in the expanded and deformed state. The resin pipe is formed inside an existing pipe, and the outside diameter of the different diameter pipe is substantially the same as the outside diameter of the different diameter pipe inside the cylindrical member. A pipe connection method in which a resin pipe connection part is formed, and the resin pipe connection part and the different diameter pipe, which are exposed by removing the tubular member, are connected in series by the pipe connection body. 2. The pipe connection method according to claim 1, wherein the different diameter pipe has an outer diameter larger than an outer diameter of the resin pipe. 3. The pipe connecting method according to claim 1, wherein a hard cylinder is fitted inside the resin pipe connecting portion after the folded pipe is formed by cooling in an expanded deformation state.