JPH05346190A - Anti-corrosion mechanical joint - Google Patents

Abstract

PURPOSE:To provide an anticorrosion mechanical joint by which corrosion of the end face of a steel pipe to generate red water and leakage of fluid in the pipe can be prevented when lining steel pipes are connected to each other. CONSTITUTION:The end part of a lining steel pipe 1 of which the inner circumferential face is coated with resin, is provided with a first enlarged diameter receiving port 11 having a little larger bore than the outer diameter of a connected lining steel pipe 1, and a second enlarged diameter receiving port 12 which is further enlarged on the extreme end side of the former port. The end part of the connected lining steel pipe 1 is inserted into the first receiving port 11, a rubber ring 3 is provided between the outer circumferential face of to pipe end and the second receiving port 12, a presser nut 2 is threadedly engaged with the thread 13 provided on the outer circumferential face of the second receiving port 12, and the rubber ring 3 is pressed with the nut 2. Further, the inner circumferential face of the end part of the connected lining steel pipe 1 is closely contacted with the outer circumferential face of cylindrical body 6 mounted on the inner side of the first receiving port 11 and connected to it. Hereby, leakage of fluid in the pipe and generation of red water can be surely prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anticorrosion mechanical joint for connecting a lining steel pipe whose inner peripheral surface is coated with resin.

[0002]

2. Description of the Related Art Conventionally, as a pipe joint for connecting a lining steel pipe, a pipe joint shown in FIG. 4 in a sectional view has been proposed. This pipe joint is connected to the expanded diameter receiving port of the lining steel pipe 1a whose inner peripheral surface is covered with resin.
Inserting the end portion of b, the press nut 2a is screwed into the screw provided on the outer peripheral surface of the receiving opening of the lining steel pipe 1a, and the press nut 2
While pressing the rubber ring 3a with a and the pipe end inclined surface,
The rear end side flange portion 31a of the rubber ring 3a is brought into contact with the end surface of the connected lining steel pipe 1b to be connected.

[0003]

However, in the case of this pipe joint, when the flange portion 31a of the rubber ring 3a is separated from the end face of the connected lining steel pipe 1b, the end face of the steel pipe not covered with the resin is inside the pipe. There has been a problem that it comes into contact with a fluid and corrodes to generate red water.

The present invention has solved the above problems and provides a corrosion-proof mechanical joint which does not cause corrosion of the steel pipe end surface to generate red water or leakage of fluid in the pipe when the lining steel pipes are connected to each other. To do.

[0005]

DISCLOSURE OF THE INVENTION The present invention provides a first expanded diameter receiving port having an inner diameter slightly larger than the outer diameter of a lining steel pipe to be connected at the end of the lining steel pipe whose inner peripheral surface is covered with resin, and The tip side is further expanded to provide a second expanded receiving port,
The end of the lining steel pipe to be connected is inserted into the first expanded diameter receiving port, and a rubber ring is interposed between the outer peripheral surface of the pipe end and the second expanded diameter receiving port. Therefore, a press nut is screwed into a screw provided on the outer peripheral surface of the second diameter-enlarged receiving port to press the rubber ring with the press-nut, and a tube mounted on the back side of the first diameter-enlarging receiving port. The inner peripheral surface of the end of the lining steel pipe to be connected is brought into close contact with the outer peripheral surface of the strip.

[0006]

Operation: When the press nut is screwed onto the screw provided on the outer peripheral surface of the second expanded diameter receiving opening of the lining steel pipe and the rubber ring is pressed by the press nut, the rubber ring causes the outer peripheral surface of the end of the lining steel pipe to be connected. Press against. Further, since the inner peripheral surface of the end portion of the connected lining steel pipe is in close contact with the outer peripheral surface of the tubular body mounted on the inner side of the first expanded diameter receiving port, the fluid in the pipe does not contact the end surface of the connected lining steel pipe, and The rubber ring prevents leakage of fluid in the pipe.

[0007]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 1 is a longitudinal sectional view of an anticorrosive mechanical joint showing an embodiment of the present invention, and FIGS. 2 and 3 are sectional views of essential parts showing another embodiment of the present invention, in which 1 is a lining steel pipe, 2
Is a retaining nut, 3 is a rubber ring, 4 is a retaining ring, 5 is a retaining ring, 6 is a tubular body, and 7 is a seal packing.

The lining steel pipe 1 is formed by coating the inner peripheral surface of the steel pipe with a synthetic resin such as vinyl chloride resin or polyethylene. At the one end of this lining steel pipe 1, the first expanded diameter receiving port 1
1 is provided, and the tip end side is further expanded in diameter to form a second expanded diameter receiving port 12
To provide. The rubber ring 3 is provided in the inner part of the second expanded diameter receiving port 12.
The inclined surface 121 for pressing is formed, and the screw 13 with which the press nut 2 is screwed is provided on the outer peripheral surface thereof. It is preferable that the outer peripheral surface of the lining steel pipe 1 is also covered with a synthetic resin.

The inner peripheral surface of the first expanded diameter receiving port 11 is formed to have an inner diameter slightly larger than the outer diameter of the connected lining steel pipe 1, and the inner diameter of the connected lining steel pipe 1 is substantially equal to the inner side of the receiving port 11. A tubular body 6 having an outer diameter is attached and adhesively bonded.
If the outer peripheral surface of the cylindrical body 6, that is, the outer peripheral surface of the cylindrical body 6 protruding toward the first expanded diameter receiving port 11 is formed into a tapered surface having an outer diameter reduced toward the opening side, The end portion of the connected lining steel pipe 1 can be easily fitted on the body 6, and after the fitting, both firmly adhere to each other.

It should be noted that, in FIG. 1, the pipe body is provided with a second expanded receiving port 1
Although the whole inner peripheral surface of the steel pipe up to 2 is integrally coated with the synthetic resin, the present invention is not limited to this structure. For example, as shown in FIG.
First cylindrical portion 6 in which the inner peripheral surface of the expanded diameter receiving port 12 is provided in the cylindrical body 6.
The first and second cylindrical portions 62 may be integrally covered, and as shown in FIG. 3, only the inner peripheral surface of the first expanded diameter receiving port 11 may be covered with the first cylindrical portion 61. Good.

According to the present invention, the end portion of the lining steel pipe 1 to be connected is inserted into the first expanded diameter receiving port 11 of the lining steel pipe 1, and the rubber ring 3 and the pressing ring 4 which have been externally fitted to the steel pipe 1 in advance. , The retaining ring 5, and the press nut 2 are moved to the pipe end side, and the press nut 2 is screwed into the screw 13 provided on the outer peripheral surface of the second expanded diameter receiving port 12 to be screwed. Then, the inclined surface 21 of the presser nut 2 and the inclined surface 1 of the second expanded diameter receiving port 12
21, the rubber ring 3, the presser ring 4, and the retaining ring 5 are pressed, and the rubber ring 3 is pressure-bonded to the inclined surface 121 of the second expanded diameter receiving port 12 and the outer peripheral surface of the end of the connected lining steel pipe 1. Watertightness is secured. Further, the retaining ring 5 has a reduced diameter, and the saw blade-shaped locking projections provided on the inner peripheral surface thereof bite into the outer peripheral surface of the end portion of the connected lining steel pipe 1, so that the pipe is prevented from coming out.

During the connecting operation, as shown in FIG. 1, a seal packing 7 made of water-expandable rubber, silicon rubber or the like is interposed on the outer peripheral side of the cylindrical body 6, and the seal packing 7 is sealed. Crimping the end surface of the connected lining steel pipe 1,
Alternatively, an adhesive may be interposed between the outer peripheral surface of the tubular body 6 and the inner peripheral surface of the end of the connected lining steel pipe 1 for connection.
Further, the seal packing 7 and the adhesive may be used together to further enhance the water tightness.

[0013]

As described above in detail, according to the present invention, the rubber ring mounted in the second expanded diameter receiving opening of the lining steel pipe is pressed by the press nut to ensure water tightness, and the depth of the first expanded diameter receiving opening is increased. Since the inner peripheral surface of the end of the connected lining steel pipe is brought into close contact with the outer peripheral surface of the tubular body mounted on the side, leakage of fluid in the pipe and generation of red water can be reliably prevented.

[Brief description of drawings]

FIG. 1 is a half sectional view of an anticorrosion mechanical joint showing an embodiment of the present invention.

FIG. 2 is a sectional view of an essential part showing another embodiment of the present invention.

FIG. 3 is a sectional view of an essential part showing another embodiment of the present invention.

FIG. 4 is a cross-sectional view of essential parts showing a conventional pipe joint.

[Explanation of symbols]

 1 Lining steel pipe 2 Presser nut 3 Rubber ring 4 Presser ring 5 Stop ring 6 Tubular body

Claims (1)

[Claims] 1. A first diameter-increasing receiving port (11) having an inner diameter slightly larger than the outer diameter of the connected lining steel pipe (1) at the end of the lining steel pipe (1) whose inner peripheral surface is coated with resin. The tip end side is further expanded to provide a second expanded diameter receiving port (12), and the end portion of the connected lining steel pipe (1) is inserted into the first expanded diameter receiving port (11). A rubber ring (3) is interposed between the outer peripheral surface of the end and the second expanded diameter receiving port (12),
The press nut (2) is screwed onto the screw (13) provided on the outer peripheral surface of the diameter expansion receiving port (12) to press the rubber ring (3) with the press nut (2), and the first expansion Diameter socket (1
1) An anticorrosion mechanical joint characterized in that the inner peripheral surface of the end of the lining steel pipe (1) to be connected is brought into close contact with the outer peripheral surface of a tubular body (6) mounted on the back side.