JP2645732B2 - Pipe fittings - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pipe joint that can electrically insulate and conduct pipes as needed.

[Prior art] In replacing old pipes in gas pipes,
Determine the degree of aging based on the age of buried pipes buried in the ground and the effect of the surrounding environment on the pipes (for example, whether the surrounding environment may cause corrosion of the pipes) However, by directly recognizing the condition of the piping, the diagnosis can be made with high precision and accuracy, the location to be repaired can be specified, and the replacement work can be partially replaced (repaired).

Therefore, as a method for directly checking the state of the pipe, the following method has conventionally been adopted. That is, a technique is adopted in which instruments for in-pipe observation, such as a camera and a fiber scope, are inserted into a pipe through an opening formed in a peripheral wall of a pipe joint for connecting the pipe, and a state of the pipe detected by these is monitored on the ground. It had been. However, the state of corrosion of the outer surface of the tube could not be judged sufficiently by observing the inner surface state of the tube.

Therefore, as a method of inspecting the outer surface state from inside the tube, a method using a sensor using the electromagnetic principle was adopted.

In the method using a sensor, the piping in the measurement section (for example, a section of about 60 m) is electrically insulated from the piping on both sides,
When a minute current flows through a pipe in the section, a voltage change that occurs in accordance with a difference in the state of each section of the pipe is detected by the sensor and displayed on an oscilloscope, a recorder, or the like on the ground.

By the way, many existing gas pipes have pipe threads set as electrical conduction lines, and tend to be continued in the future. This is because when using a pipe locator that uses the electromagnetic induction method to search for the buried position of the pipe from the ground, if the pipe is electrically insulated, it will not be possible to search for it. If an electric anticorrosion block is formed in the electric conduction line of the above, effective anticorrosion of the piping system can be performed.

In such electrically conducted piping lines,
When the method using the above-mentioned sensor is used, when examining the pipe condition, pipes having an insulating function (insulated pipe joints) are interposed on both sides of the measurement section, and the pipes in the measurement section are electrically connected to the pipes on both sides thereof. It must be insulated and returned to its original conducting state after the measurement.

Means that can meet this demand for electrical insulation recovery include:
Tubes 200, 2 connected by insulated pipe joint 100 as shown
A method of short-circuiting 00 through the conductor 300 or a method of short-circuiting the insulated pipe joint 100 and the pipes 200 on both sides thereof via the conductor 300 as shown in FIG.

[Problems to be Solved by the Invention] However, in the method described with reference to FIGS.
Thermistor 300 must be thermite-welded to the tube 200 or the insulated pipe joint 100, which is troublesome and requires skill.

The present invention has been made in view of the above problems, and an object of the present invention is to provide a pipe joint that can easily and easily electrically insulate and electrically conduct pipes as necessary. And

[Means for Solving the Problems] In order to achieve the above object, the pipe joint of the present invention has an electrically conductive insertion ring held at a pipe end insertion port whose inner surface is covered with an electric insulating layer. A tube retaining mechanism electrically connected to the tube body is provided on the inner surface of the inner ring, and the inner ring and the tube wall of the tube end insertion port are electrically connected by the insulating layer. Insulate, further threaded through the cylinder wall, screwable into this screw hole, and screwed into this screw hole and screwed up to the position where it breaks through the insulating layer, it will be inserted into the insertion ring A screw body is provided for electrically connecting the cylindrical wall and the insertion ring by making contact with each other.

[Operation] In the pipe joint having the above configuration, when the screw body is screwed into the screw hole, the electric insulating layer is pierced by the screw body, and the screw body comes into contact with the insertion ring, and the cylindrical wall of the pipe end insertion port. And the interpolation ring are electrically connected via the screw body. When the screw body is loosened from this state and pulled away from the inner ring, the electrical conduction between the cylindrical wall of the pipe end insertion port and the inner ring by the screw body is released, and the cylindrical wall and the inner ring are disconnected. Are electrically insulated.

Further, even when the electric insulating layer is not pierced by the screw body, the cylindrical wall and the inner ring are electrically insulated by the electric insulating layer.

[Embodiment] Fig. 1 is a partially cutaway side view of a pipe joint according to an embodiment of the present invention, and Figs. 2 and 3 are enlarged cross-sectional views of a main part of the pipe joint.

Reference numeral 1 denotes an electrically conductive tubular joint body. An outwardly expanding tapered surface 12 is formed on the inner surface of the pipe inlet 11 of the joint body 1, and a gasket 1 is provided between the tapered surface 12 and the pipe 200.
4 is arranged, and an annular retainer 15 is arranged on the outer surface side of the gasket 14. A female screw is formed on the outer surface of the pipe insertion port 11 of the joint body 1, and a steel press ring 13 having electrical conductivity is screwed into the female screw to compress a gasket 14 via a retainer 15 to form a tapered surface 12. Airtightness with the tube 200 is ensured. Also, the tube insertion port of the pressing wheel 13
The entire inner surface of the cylindrical wall 17 on the 16 side is covered with an electric insulating layer 18, and the inner surface of the electric insulating layer 18 is made of rubber by a tapered pressing surface 19 of an electrically conductive insertion ring 20 fitted on the inner surface. An electrically conductive ball 22 embedded and held in a retaining ring 21,
In other words, the pipe retaining mechanism is pressed against the pipe 200,
And electrical conduction between the tube 200 and the tube 200 is achieved.

In such a pipe joint, a screw hole 23 is provided through the cylindrical wall 17 so that the screw hole 23 can be screwed into the screw hole 23, and the screw hole 23 is screwed into the screw hole 23 to break through the insulating layer 18. A screw body 24 is provided which makes electrical contact between the cylindrical wall 17 and the inner ring 20 by coming into contact with the inner ring 20 when screwed.

Although FIG. 1 shows one end of the joint body 1, the other end of the joint body 1 has the same structure.

According to the above configuration, as shown in FIG.
Is electrically insulated from the tube 200,
As the screw body 24 screwed into the screw hole 23 is screwed in, the tip of the screw body 24 breaks through the electrical insulating layer 18 and the second
As shown in the figure, the tip of the screw body 24 comes into contact with the
24 and the interpolation ring 20 are electrically connected.

Accordingly, both sides (one side and the other side) of the tubes 200, 200 (only one side is shown) connected to the joint body 1
Electrical conduction is provided through the ball 22, the inner ring 20, the screw body 24, the press ring 13, and the joint body 1.

When the screw body 24 is loosened from the state shown in FIG. 2 and pulled away from the inner ring 20 as shown in FIG. 3, the electrical conduction state is released. In this case, the screw body 24 may be left in the screw hole 23 in a loosened state as shown in FIG. 3, or the screw body 24 may be removed from the screw hole 23.

By the way, as for the gas pipes and the like made of steel pipes other than the resin pipe on the outer surface, the entire pipe system is made an electrical conduction line as a countermeasure against corrosion, and an anticorrosion block is attached to the line. In such a piping system, when examining the state of the piping (for example, the uniformity of the wall thickness of the pipe wall) using the sensor described at the beginning, the measurement section is electrically insulated from the piping on both sides thereof. After the measurement is completed, it is necessary to electrically conduct the insulating portion to return to the original state. The above-mentioned pipe joint can sufficiently satisfy this demand. That is, when the measuring section is electrically insulated from the pipes on both sides of the measuring section, the screw body 24 of the pipe joint interposed on both sides of the measuring section is loosened to the state shown in FIG. 3 or the screw body 24 is removed. Pipe 200 and fitting body 1
After the measurement is completed, the screw body 24 is screwed up to a position where the electrical insulating layer 18 can be pierced, and the screw body 24 is brought into contact with the insertion ring 20 to form a tube body. 20
0 and the joint body 1 may be electrically connected.

In the above embodiment, the case where the female screw press ring 13 formed on the outer surface of the joint main body 1 is applied to a pipe joint of a screw-in type has been described. Of course, as shown in FIG. The present invention may be applied to a pipe joint in which the press ring 13 is inserted and screwed in, or may be applied to a split type pipe joint.

[Effects of the Invention] As described above, according to the pipe joint of the present invention, it is possible to electrically conduct or insulate the pipes as necessary by simply screwing or loosening the screw body. The operation is easier and simpler than that described with reference to FIGS. 5 and 6. Therefore, the pipe joint of the present invention is extremely useful when checking the state of the pipe using a sensor.

[Brief description of the drawings]

FIG. 1 is a partially cutaway side view of a pipe joint showing an embodiment of the present invention, FIG. 2 is an enlarged sectional view of a main part of FIG. 1, and FIG. FIG. 4 is a cross-sectional view showing another embodiment, and FIGS. 5 and 6 are schematic views showing a case where pipes are electrically connected to each other by conducting wires. . 16 ... tube insertion port, 18 ... electric insulating layer, 20 ... insertion ring, 2
1,22 ... pipe retaining mechanism, 23 ... screw hole, 24 ... screw body, 200 ... pipe body.

 ────────────────────────────────────────────────── ─── Continued on the front page (72) Inventor Yoshiaki Minamide 1 at 153 Tajiyonemachi, Kishiwada-shi, Osaka Nippon Steel Pipe Fitting Co., Ltd.

Claims (1)

(57) [Claims] 1. A tube which has an inner surface covered with an electric insulating layer and which has an electrically conductive inner ring held at a tube end insertion opening, and which is electrically connected to the inner surface of the inner ring. A retaining mechanism is provided, the inner ring and the tube wall of the tube end insertion port are electrically insulated by the insulating layer, and a screw hole is formed in the tube wall. Can be screwed into the screw hole,
And a screw body that is electrically connected between the cylindrical wall and the insert ring by coming into contact with the insert ring when screwed into the screw hole and screwed to a position where the insulating layer is broken through. A pipe joint characterized by the above-mentioned.