JP4169359B2 - Omnidirectional branch joint for steel pipes - Google Patents

Description

The present invention relates to a joint for connecting a branch pipe to an existing steel buried gas pipe.

At present, PE pipes (polyethylene pipes) are used as gas pipes, but most of the existing gas main pipes are steel pipes made of steel or cast iron. It is considered unpreferable in terms of earthquake resistance to take out the branch pipe by screw connection as shown.
For this reason, a joint has been proposed in which a pair of clamp fittings divided into two are attached to the gas main pipe, and the end of the PE connection pipe connected in advance to one of the pipes is eccentrically cut off by the side of the pipe with a dedicated drilling machine. ing.
In this joint, it is necessary to expose the entire circumference of the buried gas pipe as in the conventional method. In addition, since a dedicated drilling machine has to be used, the operation time is long and the construction cost is high.

Japanese Patent Laid-Open No. 2004-360858 (FIG. 1)

The present invention provides a branch joint that can be operated without exposing the entire circumference of an existing steel pipe, can be attached to the pipe axis in any direction, regardless of the pipe diameter, and without using a dedicated tool. is there.

In the branch joint of the present invention, a gas introduction socket having a female screw for a closing plug on the upper inner surface is welded and fixed upright on an existing steel gas pipe, and the leg part of the T-shaped joint pipe having a cylindrical leg part is a gas The joint pipe that surrounds the outer periphery of the introduction socket and is welded and fixed to the gas pipe is provided with a work socket with a plug on the joint pipe, and one end of the joint pipe serves as a branch pipe connection port and the other. The end is used as a work port.
The T-type fitting pipe leg may be welded to a mounting outer cylinder that is pre-welded to the gas pipe surrounding the gas introduction socket, and further, a mounting flange is formed on the T-type fitting pipe leg or the mounting outer cylinder. It is good to keep.

In the joint according to the present invention, since the working excavation mine is shallow, the work cost is reduced and the work is facilitated. In addition, the angle of attachment of the T-shaped joint pipe to the main pipe can be set freely, so that the branch pipe can be taken in all directions.
In addition, each member constituting the joint pipe can be manufactured using an off-the-shelf product, and a drilling machine or the like does not require a dedicated tool and uses a conventional tool, so that it is economical. Can be used repeatedly.

The branch pipe joint of the present invention will be described together with a construction method.
In the figure, reference numeral 1 denotes, for example, a 300 A steel gas pipe buried in the ground (the anticorrosion coating is omitted), and the mounting surface F is exposed in the excavated work mine H.
Reference numeral 2 denotes a gas introduction socket having a female screw 3 for a closing plug on the upper inner surface, the bottom surface of which is formed in an arc surface matching the diameter R of the gas pipe, and is fixed upright on the gas pipe by welding. The introduction socket is preferably thick in order to avoid thermal distortion due to welding.
4 is a gas inlet port drilled in the gas pipe, and 5 is a block-like closing plug screwed after drilling, having a male screw 6 on the peripheral surface, and a hexagonal hole 7 for rotation at the center of the upper surface. And is attached and detached by a rotating tool inserted from a work socket described later. (Figure 2)
That is, the gas introduction port in the gas introduction socket is pierced by a normal drilling machine (hole saw) inserted from the work socket 18 after socket welding, and then the upper part of the socket is closed by a closing plug. After the joint pipe is attached, the joint pipe is taken out and reused for other construction.

Reference numeral 8 denotes a T-shaped joint pipe, which can be manufactured by welding appropriate pipe bodies 12 and 13 to both ends of a ready-made cheese.
14 is a connection port for connecting a mechanical transition PE pipe and the like, 15 is a cover cap, 16 is a work port at the other end, and 17 is a cap.
Reference numeral 18 denotes a work socket projecting on a joint pipe positioned directly above the gas introduction socket 2, and 19 denotes a plug having the same configuration as the closing plug.
Reference numeral 9 denotes a cylindrical leg portion of the T-shaped joint pipe. In FIG. 3, a mounting outer cylinder 10 provided with a flange 11 is continuously provided. Although the cylindrical leg portion 9 can be directly fixed to the gas pipe, it may be welded to an outer cylinder attached in advance on the gas pipe as shown in FIG.
3 (A) shows the welding of the introduction socket 2, FIG. 3 (B) shows the plug closed after drilling, and FIGS. 3 (C) and (D) show the flanged outer cylinder legs of the T-shaped joint pipe 8. FIG. 4A and FIG. 4B show an example in which the outer cylinder 10 is pre-installed.

Each of the above operations is performed in an airtight bag (no blow bag) (not shown), and a leak inspection is performed on the way, but this description is omitted.
In the joint of the present invention, the mounting direction of the joint pipe can be freely set as shown in FIG. 5 by any of the above methods.

Partially cutaway sectional view of the joint of the present invention attached to a gas main pipe Enlarged sectional view of the closing plug It is a side view which shows the attachment process of a joint pipe, (A) is fixation of an introduction socket, (B) is mounting | wearing with a closing plug, (C) (D) shows attachment of a joint pipe leg outer cylinder, respectively. Installation process diagram of outer cylinder and joint pipe by other methods The top view which shows the attachment state of this invention coupling

Explanation of symbols

1
Steel gas pipe
2 Gas inlet socket
3 Female thread
4 Gas inlet
5 Closure plug
6 Male thread 7 Rotating square hole 8T type fitting tube 9 Leg
10 outer cylinder
11 Flange
12, 13 Pipe member
14 Branch pipe connection port
15 Cover cap
16 Working port
17 cap
18 Work socket
19 Plug

Claims (3)

A gas introduction socket having a female screw for a closing plug on the upper inner surface is fixed upright on an existing steel gas pipe, and the leg portion of the T-shaped joint pipe having a cylindrical leg portion surrounds the outer periphery of the gas introduction socket. A work socket with a plug is provided in the joint pipe that is welded and fixed to the surface of the gas pipe and is located immediately above the introduction socket, and one end of the joint pipe is used as a branch pipe connection port and the other end is operated. An omnidirectional branch joint for steel pipes characterized by a mouth. 2. The omnidirectional branch joint for steel pipes according to claim 1, wherein the T-shaped joint pipe leg portion is welded to a mounting outer cylinder surrounding the gas introduction socket and previously welded to the gas pipe. 3. The omnidirectional branch joint for steel pipes according to claim 1 or 2, wherein a welding flange is formed on a T-shaped joint pipe leg or a mounting outer cylinder.

Images