JPH0310469Y2 - - Google Patents

Description

[Detailed description of the invention] (Field of industrial application) The present invention relates to a pipe joint for a lined pipe in which the inner peripheral surface of a metal pipe is coated with a synthetic resin layer, and more specifically, the pipe joint for a lined pipe in which the inner peripheral surface of a metal pipe is coated with a synthetic resin layer. This invention relates to a pipe joint that is integrally coated with a resin cap to improve corrosion resistance.

(Prior art and its problems) Conventionally, galvanized steel pipes have been used for water supply or hot water supply piping, but because galvanized steel pipes have the problem of generating red water, in recent years medium- and high-rise residential buildings have Lining pipes coated with a layer of synthetic resin such as vinyl chloride resin have come into use.

Generally, a mechanical joint (see Figure 1) is used to connect the lining pipes together, and after attaching a synthetic resin cap with a U-shaped cross section to the end of the lining pipe, the end of the lining pipe is connected. It was inserted into the socket of the joint body, and a rubber ring was attached to the outer circumference of the pipe, and the connection was made using a flange protruding from the socket end of the joint body, a press ring, bolts, and nuts.

However, with the synthetic resin caps used in conventional fittings, the width of the outer cylinder that covers the outer peripheral surface of the pipe end is narrow, and the cap is hidden inside the push ring, making it difficult to attach the cap after piping construction. There was a problem that it was not possible to judge whether the That is, in the case of piping construction on site, the lining pipe is cut to the desired length and a synthetic resin cap is attached to the end of the pipe, so workers can forget to attach the cap and simply connect it. If a cap is not attached to the end of the lining pipe, the end surface of the metal pipe exposed at the end of the pipe is corroded by the fluid inside the pipe, causing a problem that red water is generated. Further, as the corrosion progresses at the end of the pipe, the connection with the joint body becomes incomplete, and the fluid within the pipe sometimes leaks.

In this invention, the synthetic resin cap attached to the end of the lining pipe is made wider than before, and the rear end of the outer cylinder that covers the outer peripheral surface of the pipe end protrudes outward from the press ring. This allows you to check the installation status of synthetic resin caps at a glance even after piping construction.
The present invention provides a pipe joint for a lined pipe that can prevent occurrence of red water, leakage of fluid inside the pipe, etc.

(Means for solving the problem) In the pipe joint of the present invention, the pipe end of the lining pipe 1 whose inner peripheral surface is coated with the synthetic resin layer 12 of the metal pipe 11 is inserted into the socket 31 of the joint body 3. The socket 31
The flange 32 protruding from the end of the socket 3 and the press ring 4 are connected by bolts 6 and nuts 7, and the socket 3
A rubber ring 5 interposed between the opening of 1 and the press ring 4
1 is brought into close contact with the outer peripheral surface of the lining pipe 1, and an outer cylinder 21 is provided at the end of the lining pipe 1.
A synthetic resin cap 2 having a U-shaped cross section is attached, in which an inner cylinder 22 and an inner cylinder 22 are joined at a bottom wall 20, and the rear end of the outer cylinder 21 is made to protrude outward from the press ring 4. It is.

Hereinafter, the specific configuration of the present invention will be explained in detail based on examples.

(Example) Fig. 1 is an upper half sectional view showing an embodiment of the present invention, and Fig. 2 is a sectional view of the main part of the lining pipe of the present invention, in which reference numeral 1 is the lining pipe, and 2 is the composite pipe. Resin cap, 3 is the joint body, 4 is the press ring, 51
is a rubber ring, 52 is a collar, 53 is a lock ring,
6 is a bolt and 7 is a nut.

The lining tube 1 is a metal tube 11 whose inner peripheral surface is coated with a synthetic resin layer 12 such as vinyl chloride resin, polyethylene resin, polypropylene resin, etc., and a synthetic resin cap 2 is attached to the end of the lining tube 1. It is installed.

The cap 2 is made of synthetic resin such as vinyl chloride resin or polyethylene resin, and includes an outer cylinder 21 having an inner diameter approximately equal to the outer diameter of the lining pipe 1, and an inner cylinder 22 having an outer diameter approximately equal to the inner diameter of the outer cylinder 21. are joined by a bottom wall 20 to form a U-shaped cross section. The wall thicknesses of the outer tube 21 and the inner tube 22 are not particularly limited, but are preferably about 0.3 to 2.0 mm depending on the diameter of the lining tube. Further, the width dimension of the inner cylinder 22 is not particularly limited, but
It is important that the width L of the outer tube 21 is formed so that the rear end of the outer tube 21 protrudes outward from the press ring 4 when connected as shown in FIG.

This cap 2 is attached to the end of the lining pipe 1 during piping construction on site.
After applying a rust preventive agent to the end surface of the metal tube 11, an adhesive is applied to the inner peripheral surface of the cap 2 to join them.

It is more preferable to make the cap 2 transparent, since this allows the state of application of the rust preventive agent to be visually confirmed.

After the cap 2 is attached to the end of the lining pipe 1 in this manner, it is inserted into the socket 31 of the joint body 3. Therefore, the rubber ring 51, collar 52, lock ring 53, and press ring 4 that have been inserted into the lining pipe 1 in advance are brought close to the joint body 3, and the bolt 6 is inserted into the flange 32 and the press ring 4 that protrude from the joint body 3. A nut 7 is screwed onto the bolt 6.

Thus, as shown in FIG.
and the joint body 3 are connected. In this connected state, the end of the lining pipe 1 is completely covered with the synthetic resin cap 2, so the metal pipe 1
The end face of the pipe No. 1 is not corroded by the fluid inside the pipe. In addition, since the outer cylinder 21 of the cap attached to the end of the lining pipe 1 protrudes from the outside of the press ring 4, it is easy to check whether the cap 2 is attached or not even after piping construction. If the cap 2 is not attached, it is sufficient to disconnect the connection and attach the cap to the end of the lining tube 1.

(Operations and Effects of the Invention) As detailed above, in the present invention, the outer cylinder of the synthetic resin cap attached to the end of the lining pipe is made to protrude outward from the press ring, so that the cap can be maintained even after piping construction. It is easy to check whether the cap is attached or not, and if the cap is not attached, all you have to do is disconnect it and attach the cap, so it is possible to prevent the occurrence of red water due to the operator's carelessness.

[Brief explanation of the drawing]

FIG. 1 is an upper half cross-sectional view showing an embodiment of the present invention, and FIG. 2 is a cross-sectional view of the main part of the lining pipe of the present invention. 1... Lining pipe, 11... Metal pipe, 12...
...Synthetic resin layer, 2...Synthetic resin cap, 20
... Bottom wall, 21 ... Outer cylinder, 22 ... Inner cylinder, 3 ...
Joint body, 31... Socket, 32... Flange, 4
... Push ring, 51 ... Rubber ring, 52 ... Color, 5
3... Lockling, 6... Boruto, 7... Natsuto.

Claims (1)

[Scope of utility model registration request] The pipe end of the lining pipe 1 whose inner circumferential surface of the metal pipe 11 is coated with a synthetic resin layer 12 is inserted into the socket 31 of the joint body 3, and the flange 32 protruding from the end of the socket 31 is inserted. The push ring 4 is connected with the bolt 6 and the nut 7, and the opening of the socket 31 and the push ring 4 are connected.
The rubber ring 51 interposed between the lining pipe 1
In the pipe joint that is brought into close contact with the outer circumferential surface of the lining pipe 1, a synthetic resin cap 2 having a U-shaped cross section, in which an outer cylinder 21 and an inner cylinder 22 are joined at a bottom wall 20, is attached to the pipe end of the lining pipe 1; The rear end of the outer cylinder 21 is connected to the push ring 4
A pipe joint for a lined pipe characterized by protruding further outward.