JPH10185022A - Connection construction for gas pipeline - Google Patents

Abstract

PROBLEM TO BE SOLVED: To try to surely and simply connect the inlet steel pipe of gas piping with a buried polyethylene pipe identical to the outer diameter of the aforesaid steel pipe or fairly smaller in an inner diameter by means of an fitting method. SOLUTION: In this connection construction, a metallic press ring type joint pipe 8 is prepared, which comprises the inner circumferential tapered surface formed up, where the tapered surface is gradually so narrowed from a receiving part 10 fitted with the outer circumferential surface at the tip end of a polyethylene pipe 7 so as to be an inner diameter capable of accepting no polyethylene pipe 7, the polyethylene pipe 7 is heated at its tip end, and concurrently let the press ring type joint pipe 8 cover the tip end part of the steel pipe 1 from the opposite side of the receiving port 10, and its tip end part is projected so as to allow the tip end part of the steel pipe 1 to be fitted in the polyethylene pipe 7 that is softened by heating, and further the polyethylene pipe 7 is compressed by fitting the receiving port 10 of the press ring type joint pipe 8 in the tip end of the polyethylene pipe, and also twisting and advancing the receiving port in the direction of the screw groove, so that the entire body of the joint pipe 8 is thereby substantially engaged with the outer circumference of the polyethylene pipe 7.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention connects an iron pipe at an inlet of a gas pipe to a house or another gas consuming facility with a polyethylene pipe or a similar synthetic resin pipe forming a branch of the buried main pipe. It is related to the method of construction.

[0002]

2. Description of the Related Art In order to connect an inlet iron pipe of a gas concentration or individual pipe to a buried main pipe, some kind of joint means is required. In recent years, polyethylene pipes have been widely used as the main pipe.However, in order to connect this polyethylene pipe to another polyethylene pipe or iron pipe of the same outer diameter, it is not a simple screwed iron socket but a connection. A mechanical joint is used in which abutting ends of two pipes to be received and tightened from both sides are used. Mechanical fittings,
In particular, a socket-type mechanical joint generally has a tubular joint body, a pair of push rings engaged with both ends of the joint body, and a rubber ring for tightening a connected pipe according to a screw engagement depth between the joint body and the push ring. It consists of a tightening member.

[0003] In this case, if the inlet iron pipe of the gas pipe has a small diameter (for example, 6 minutes: 3/4 inch pipe) different from a normal type (so-called inch pipe) for city gas, a polyethylene pipe for main pipe ( Inch pipe) must first be connected to an inch iron pipe by a mechanical joint, and this iron pipe must be screwed into the large-diameter side of the reducer-type iron socket, and its small-diameter side must be connected to the inlet iron pipe. However, in order to make a connection with only one mechanical joint and an iron socket in this way, it is necessary to cut a screw into the tip of a small-diameter iron pipe protruding from the house side in a vertical hole formed by digging up the adjacent ground such as a house. However, it requires extremely troublesome work such as rotating the iron pipe for screw tightening.

[0004] Therefore, the method currently used is to use a second mechanical joint, which is commercially available for connecting small-diameter pipes, with the tip of a small-diameter iron pipe protruding into a vertical hole and the iron socket. The tip of the small-diameter iron pipe screwed to the small-diameter side is connected. FIG. 1 shows such a pipe connection, in which 1 is a small-diameter iron pipe protruding into a vertical hole, 2 is a mechanical joint for a small-diameter iron pipe having both-end pressing portions 2a and 2b, and 3 is a large-sized iron socket 4 in advance. A small-diameter iron pipe for relay, screwed to the radial end, 5 is a normal-diameter (inch-diameter) iron pipe similarly screwed to the large-diameter end, 6 is a pressing ring portion 6a,
A large-diameter mechanical joint 6b has a polyethylene pipe 7 as a main pipe branch.

[0005]

In the above described gas pipe connection method, since an iron socket is used in addition to two mechanical joints having relatively complicated and expensive structures, the material cost and labor (two types of iron sockets) are required. (Including the labor of screwing the relay iron tube). In addition, there are a total of six connection points, both ends of each of the two mechanical joints and both ends of the iron socket, and it is clear that the probability of gas leakage due to mechanical load or impact increases accordingly.

As shown in FIG. 2, the present invention is applicable to the case where the outer diameter A of the small-diameter iron pipe 1 protruding into the vertical hole is slightly larger than the inner diameter B of the polyethylene pipe 7 as a main pipe branch. Without using complicated joint combinations,
It is intended to simply and surely connect the two in the fitting method.

[0007]

SUMMARY OF THE INVENTION In order to solve the above-mentioned problems, the present invention relates to an end of a polyethylene pipe which forms a branch of a buried main pipe and an inlet of a gas pipe to a house or another gas consuming facility. A method of connecting a tip of an iron pipe having an outer diameter that can be fitted into the polyethylene pipe or that is slightly larger than the inner diameter of the polyethylene pipe; It has a receiving port fitted to the distal end outer peripheral surface, and has a tapered inner peripheral surface that gradually narrows from the diameter of the receiving port and has a diameter that cannot always receive the polyethylene pipe. Prepares a metal push ring type joint pipe in which a thread groove is cut into the outer circumference of the polyethylene pipe, and b) heats the polyethylene pipe to soften its tip. c) covering the leading end of the iron tube from the opposite side of the receiving port with the pressing ring type joint pipe so that the leading end protrudes from the receiving port; and d) softening the leading end of the iron pipe by the heating. E) fitting the receiving port of the push ring type joint pipe with the tip of the polyethylene pipe and twisting it in the direction of the screw groove, thereby e. While engraving and compressing a screw around the outer circumference of the joint, substantially the entire joint pipe is engaged with the outer circumference of the polyethylene pipe, and the inner peripheral surface of the compressed polyethylene pipe is pressed against the outer peripheral face of the tip end of the iron pipe. It was made.

[0008] As a prerequisite for the above-mentioned method, the phrase "the end of the polyethylene pipe can be fitted into the outer diameter of the iron pipe" means that the iron pipe is easily inserted into the normal polyethylene pipe by hand. In the present invention, including this degree of relationship, the case where the inner diameter of the polyethylene pipe is slightly narrow (normally, the tip surfaces of both pipes collide with each other and the iron pipe is not inserted) is intended. . As a precautionary measure, "softening" in the step b "heating to soften" is to make the slightly narrow inner diameter of the polyethylene pipe soft enough to be expanded by inserting an iron pipe. Performing the joint pipe covering operation on the iron pipe in the step c) is nothing more than performing the operation in parallel with or before or after the heating.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will be described below with reference to the drawings.

[0010]

In FIG. 3, the distal end of an iron pipe 1 serving as an inlet of a gas pipe to a house or another gas consuming facility has an inner diameter (standard inch diameter) slightly smaller than the outer diameter of the iron pipe 1. In addition, the distal end of a polyethylene pipe 7 forming a branch of the buried main pipe is opposed to the iron pipe 1, and a metal pressing ring type joint pipe 8 having a tapered threaded inner peripheral surface that is sufficiently larger than its outer diameter is provided on the iron pipe 1. Covered and supported. The tapered inner peripheral surface 9 of the joint pipe 8 gradually narrows from a receiving port 10 having a diameter that can be fitted to the outer peripheral surface of the distal end of the polyethylene pipe 7, and has a size that cannot accept the polyethylene pipe 7 soon. ing. In the thread groove formed in the inner peripheral surface 9, a complete thread is formed at the rear end of the joint pipe 8, that is, at the opposite end of the polyethylene pipe 7 in the state of FIG. 3, and the thread advances toward the front end. Then, the tapered portion is gradually chipped to reach the receiving port 10, but the screw thread may be eliminated in front of the receiving port 10 and only the tapered surface may be provided.

According to the present invention, before and after the above-described operation of placing the joint pipe 8 on the iron pipe 1, the tip of the polyethylene pipe 7 facing the iron pipe 1 is heated by a torch lamp or an annular heater or the like so as to be softened. I do. This heating range H is made sufficiently longer than the length of the joint pipe 8. In addition,
It is desirable to apply an appropriate metal fitting (which may also serve as the joint pipe 8) so that the opening at the tip of the polyethylene pipe 7 does not expand too much due to heating.

Next, as shown in FIG. 4, a state is maintained in which the distal end of the iron pipe 1 is sufficiently protruded from the receiving port of the ring-type joint pipe 8, and the distal end of the iron pipe 1 is softened by the heating. The expanded polyethylene pipe 7 is inserted into the end of the polyethylene pipe 7. Preferably, if the tip outer peripheral surface of the iron pipe 1 is chamfered by applying a file, and the inner peripheral surface of the polyethylene pipe 7 is chamfered or rounded as shown by 11 in FIG. The first insertion of the tip of the iron tube 1 is easy. Thereafter, if the iron tube 1 is pushed into the polyethylene tube 7 (in this case, about 10 cm), the tube 7
Accordingly, the enlarged portion formed by the insertion of the iron pipe extends rearward, whereby the fitted / fixed state shown in FIG. 4 can be finally established.

The distal end of the polyethylene tube 7 absorbs heat by the above-described insertion of the iron tube, and when the outer peripheral surface of the polyethylene tube 7 is brought into a hardened state in which the hardness has recovered to a certain degree, the receiving port 10 of the press ring type joint tube 8 is connected to the polyethylene. At the same time as fitting to the tip of the pipe 7, this joint pipe 8 is screwed into the polyethylene pipe 7 in the direction of the inner peripheral thread groove. As a result, while the screw is cut and compressed on the outer peripheral surface of the polyethylene pipe 7, substantially the entirety of the joint pipe is engaged with the outer circumference of the polyethylene pipe. As shown in FIG. 5, this engaged state is such that the front end of the polyethylene pipe 7 coincides with or slightly projects from the rear end of the joint pipe 8, whereby the inner peripheral surface of the compressed polyethylene pipe becomes the iron pipe 1 The iron tube 1 and the polyethylene tube 7 can be completely connected to each other firmly to the outer peripheral surface of the distal end portion.

[0014]

As described above, according to the present invention, even when the outer diameter of the iron pipe protruding into the vertical hole is slightly larger than the inner diameter of the polyethylene pipe as the main pipe branch, the fitting using the simple single-piece joint pipe is adopted. In the combined system, the two can be easily and reliably connected. In particular, there is only one connection point according to the method of the present invention, and since this is firmly joined by the joint pipe, there is no danger of gas leakage due to mechanical load or impact. It is clear that the improvement is remarkable.

[Brief description of the drawings]

FIG. 1 is a vertical sectional view showing a complicated aspect of a conventional small-diameter iron pipe / polyethylene pipe connection.

FIG. 2 is a cross-sectional view of a polyethylene pipe for showing a dimensional relationship between an iron pipe to be connected by the above-described conventional method and the method of the present invention and a cross-section of a polyethylene pipe.

FIG. 3 is a longitudinal sectional view showing a first half step of the method of the present invention.

FIG. 4 is a semi-longitudinal sectional view showing a middle step of the method of the present invention.

FIG. 5 is a longitudinal sectional view showing an end stage of the method of the present invention.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Iron pipe 7 Polyethylene pipe 8 Press ring type joint pipe 9 Inner peripheral taper surface 10 Receiving port 11 Chamfer

Claims (1)

[Claims] 1. An iron pipe forming an end of a polyethylene pipe forming a branch of a buried main pipe and an inlet of a gas pipe to a house or another gas consuming facility, etc., which can fit into the polyethylene pipe. Or a method for connecting the tip of the iron pipe having an outer diameter slightly larger than the inner diameter of the polyethylene pipe, a) having a receiving port fitted to the outer peripheral surface of the tip of the polyethylene pipe; It has a tapered inner peripheral surface that gradually narrows from the diameter of the inlet and has a diameter that cannot normally accept the polyethylene pipe, and has a thread groove cut into the outer peripheral surface of the polyethylene pipe. And b) heating the polyethylene pipe so as to soften its tip, and c) moving the push ring-type joint pipe to the opposite side of the receiving port. And d) fitting the tip of the iron tube into the end of the polyethylene tube that has been softened by the heating, and e) fitting the tip of the iron tube into the tube so that the tip protrudes from the receiving port. By fitting the receiving port of the press ring type joint pipe to the tip of the polyethylene pipe and twisting it in the direction of the screw groove, a screw is formed on the outer circumference of the polyethylene pipe and compressed, thereby forming the joint pipe. A method of connecting gas pipes, wherein substantially the entirety is engaged with the outer circumference of the polyethylene pipe, and the inner circumference of the compressed polyethylene pipe is crimped to the outer circumference of the tip of the iron pipe.