JPH0565025B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention provides a method for detecting damage to the coating of a pipe whose inner surface is coated, or for applying externally powered cathodic protection to the inner surface of the pipe. The present invention relates to an electrode member installed in a conduit.

[Problems to be solved by conventional technology and invention]

The conventional and common method for detecting damage to the inner surface coating of pipes is to disassemble and investigate the pipe, but other methods are also available, such as inserting a camera into the pipe and observing the damage. However, even the latter requires an entrance to insert the camera, and
There are also restrictions on the pipe diameter. In addition, both methods require scanning the entire length and circumference of the pipe, which requires an enormous amount of time and is not suitable for constant monitoring.

Damage to the inner coating, regardless of its size, is a serious problem that can lead to corrosion perforation within the pipeline, so it is important to detect the damage within a short period of time after it occurs, accurately identify the location, and repair it as soon as possible. It is desirable to do so. For this purpose, it is necessary to conduct damage inspections frequently, so there has been a strong desire for a method that can easily detect all the holes in the pipeline.

The inventors of the present invention have conducted various studies in view of this situation, and have found that the presence or absence of damage to the coating and its location can be determined by utilizing the principle that the electrical resistance of the liquid in the pipe in the longitudinal direction of the pipe is proportional to the length of the pipe. We have developed a method to identify this. In this method, at two points appropriately spaced apart in the longitudinal direction of the pipe,
An electrode that is conductive to the liquid inside the tube but not conductive to the tube body, and a terminal is connected to the tube body, and the resistance between the electrode and the terminal is measured, or a current is measured between the electrodes at two points. By measuring the potential difference between each electrode and terminal at that time, the presence or absence of damage to the coating and its location can be detected. Therefore, to implement this method, it is essential to install an electrode that conducts the liquid in the pipe, and it is desired to develop an electrode that has a simple structure, is easy to install in the pipe, and operates reliably. was.

The present invention was made based on such a need, and it is an object of the present invention to provide an electrode member for energizing a liquid in a pipe, which has a simple structure, is extremely easy to attach to a pipe, and can be operated reliably. purpose.

[Means for solving problems]

The present invention, which has been made to achieve the above object, provides a wetted outcrop made of an electrical conductor on the inner surface of an insulating sealing material attached to a pipe connection part, and encapsulates the wetted outcrop in the sealing material. The gist of the present invention is an electrode member for supplying electricity to a liquid in a conduit, which is characterized in that the electric conductor is electrically conductive to the outer peripheral end surface of a sealing material.
Here, the insulating sealing material does not necessarily need to be insulative as a whole, as long as at least the exposed liquid and the portion where the conductor is arranged are insulative.

[Effect]

Since the electrode member of the present invention is configured as described above, it can be used in the same way as a normal sealing material at the connection part of each pipe when connecting pipes to form a conduit, and it is easy to install. It is easy to seal the connection part. Moreover, when it is attached to a pipe connection, the liquid outcrop provided on the inner surface contacts the liquid in the pipe line and conducts, and this liquid outcrop is connected to the sealing material by the electrical conductor sealed in the sealing material. Since it is electrically conductive to the outer peripheral end surface, it can be used as an electrode for supplying electricity to the liquid in the pipe.

〔Example〕

Embodiments of the present invention shown in the drawings will be described below.

FIG. 1 is a plan view of an electrode member according to an embodiment of the present invention, and FIG. 2 is a sectional view thereof. In the same figure, an electrode member designated as a whole by reference numeral 1 has a conductor 3 made of a metal wire attached to a sealing material 2 made of a gasket-like insulator for a flange connection part.
A is sealed so as to be exposed from the inner periphery to form a wetted outcrop, and the tip of the metal wire 3 is connected to the connection terminal 4 at the tip of the protrusion 2A of the sealing material 2.

Next, a method of using the electrode member 1 will be explained. FIG. 3 is a schematic sectional view showing a conduit using the above electrode member, in which 6 is a metal tube, 7 is a flange for connecting the metal tube 6, 8 is a polyethylene tube formed on the inner surface of the metal tube, Insulating coating such as polyurethane, 9
10 is the penetration damage that occurred in the coating 8, and 10 is the metal tube body 6.
This is the terminal connected to. Electrode member 1 shown in FIG.
The gaskets are inserted and attached to the flange connections located at appropriate intervals in the longitudinal direction of the conduit in the same manner as ordinary gaskets. In this electrode member 1, the seal material 2 acts as a seal to prevent leakage between the flanges, and at the same time, the conductor 3 sealed in the seal material 2 is insulated from the tube body 6 but passes through the tube. It acts as an electrode that conducts to the liquid through the liquid contact outcrop 3A.

As shown in FIG. 3, if there is damage 9 to the coating,
Since the metal tube 6 comes into contact with the liquid in the tube at the location of the damage, the metal tube 6 serves as a terminal that is electrically connected to the liquid in the tube at the damaged portion of the coating. Therefore, the terminals 4 of the two electrode members 1, 1 arranged at appropriate intervals in the conduit,
Based on the input/output relationship of electrical signals to the three terminals 4 and 10 connected to the tube body 6, it is possible to determine whether or not there is damage to the coating or where it exists. For example, if the electrical resistance between one electrode member 1 and the metal pipe body 6 is measured and this is infinite (a certain value or more),
It is verified that there is no damage to the coating. In addition, the above 2
If the potential difference E 1 between one electrode member 1 and the metal pipe body and the potential difference E ₀ between both electrode members ₁ , 1 are measured while energizing the electrode members 1, 1, both electrode members 1, 1 The distance between them is l ₀ , and l ₁ =l ₀ E ₁ /E ₀ represents the distance from one electrode member 1 to the position of the coating damage 9. In this way, the location of damage to the coating can be detected. Note that it is of course possible to apply measures other than the above example.

Since the conduit shown in FIG. 3 is coated with an insulating inner surface, the effective distance for cathodic protection is long, and therefore externally powered cathodic protection is extremely effective. As mentioned above, the conductor 3 of the electrode member 1 is insulated from the tube body 6 but conductive to the liquid inside the tube, so it is also possible to use this conductor 3 as an electrode for externally powered cathodic protection. It is.

As is clear from the above embodiments, the first requirement of the electrode member of the present invention is that when the member is applied to a pipe, conduction is ensured from the wetted outcrop to the outside of the pipe and that it is connected to the metal pipe body. This is done to maintain insulation.
For this purpose, first, it is desirable that the outcrop in contact with the liquid has a surface area of a certain degree or more depending on the pipe diameter.
In general, as long as there is no problem with flow, the larger the diameter, the lower the electrolytic polarization and the resistance in contact with the liquid, and the smaller the measurement error. FIG. 4 is a perspective view showing an embodiment of the present invention in which a liquid contacting area is enlarged, and FIG. 5 is a sectional view showing a state in which the electrode member shown in FIG. 4 is attached to a flange connection portion. The electrode member 11 of this embodiment has a conductor 13 made of a metal plate enclosed in a gasket-shaped sealing material 12, with parts 13A of the conductor 13 protruding from a plurality of locations on the inner peripheral surface of the sealing material 12, and extending in a substantially perpendicular direction. It is bent to form a liquid contact outcrop, and the tip of the conductor 13 is connected to the terminal 14 at the tip of the protrusion 12A of the sealing material 12. This electrode member 11 is also used in the same manner as the electrode member 1 shown in FIG. Note that the electrode may be brought into contact with the liquid at one point on the circumference, but the contact points may be arranged equidistantly in the circumferential direction as in the illustrated embodiment, or continuously in the circumferential direction. It is preferable to arrange the tubes in such a way that the resistance in contact with the liquid decreases and the current distribution within the tube becomes uniform.

In the electrode member of the present invention, in order to have good insulation extending to the outside of the tube, the conductive path from the exposed liquid to the terminal outside the tube is isolated from the metal tube or the ground in a water-stop state. There is a need. For this reason, in the above embodiment, when the electrical conductor is sealed in the gasket-shaped sealing material, it is desirable that water be reliably sealed between the electrical conductor and the sealing material. For this purpose, there is a method of manufacturing a sealant encapsulating a conductor as shown in the illustrated embodiment by integrally molding an elastomer such as chloroprene rubber or polyurethane and a conductor, or a method of preparing two sheets of sealant in advance, A method in which a conductor is sandwiched between them, and an elastomer such as chloroprene rubber or polyurethane, or a resin such as polyphrein or vinyl chloride is interposed on the joint surface and integrally molded, between two gasket-shaped unvulcanized rubber molded bodies. It is preferable to manufacture the electrode member by a method such as sandwiching a conductor between the two and vulcanizing and adhering it, or integrating with a hot melt adhesive.

Next, among the conductors used in the electrode member of the present invention, it is preferable to use a conductor that is difficult to be eroded by the fluid in the pipe, at least at the outcrop in contact with the liquid. Copper/nickel alloys, stainless steel, etc. are suitable for seawater and many other liquids. Furthermore, platinum or platinum-plated material can also be used for special purposes. Conductive resins (resins that are themselves conductive or resins that are made conductive by adding conductive fillers, etc.) and ceramics (carbon, titanium boride, silicon carbide, titanium carbide, etc. that are themselves conductive) cermets made of composites of fibers and metals, etc.) may also be used. When used for cathodic protection, attention should also be paid to durability under continuous energization. The conductor is
It may be manufactured by processing wire rods, plate materials, tubular materials, or block materials, or it can be molded all at once by casting. It is best to integrally mold each part from the outcrop to the external terminal from raw materials, but it is also possible to create each part separately and then integrate them by a method such as soldering.

Although the above explanation is based on the case where the present invention is applied to a gasket for flange connection, the electrode member of the present invention is not necessarily limited to the gasket shown in FIG. 1 or 4, and can be used for piping. It is also applicable to any sealing material placed at the connection. FIG. 6 shows an embodiment in which the present invention is applied to a Victorique type connector. In the same figure, 2
Reference numeral 0 designates the entire Victory type connector, 21 represents tube bodies connected to each other by the Victory type connector 20, and 22 represents an insulating coating on the inner surface thereof. Victory fitting 20 consists of a housing 23 and a sealing ring or material 24 disposed therein. An insulating member 25 is attached to the sealing material 24 at the center in the tube axis direction, and a conductor 26 is enclosed within the insulating member 25. The inner end of the sealing material 24 of the electrical conductor 26 is exposed to form a liquid contact outcrop 26A, and the opposite end penetrates the housing 23 and protrudes to the outside to form an external connection terminal 26B.
Note that the portions of the conductor 26 other than the liquid contact outcrop 26A and the external terminal 26B are insulated by an insulating member 25, and are configured to maintain insulation with respect to the tube body 21 and the housing 23. In this embodiment, the sealing material 24, the conductor 26, etc. constitute an electrode member, and this electrode member is also attached to the connection part of the tube body, similar to the gasket-shaped electrode member shown in FIG. 1 or 4. It acts as an electrode to supply electricity only to the liquid inside the tube from the outside.

〔Effect of the invention〕

As is clear from the above description, the electrode member of the present invention is used in the same way as a normal sealing material used for pipe connections, and although it exhibits a sealing effect, it conducts only from the outside of the pipe to the liquid inside the pipe. It has the advantage of being extremely easy to install, and can be effectively used as an electrode for detecting damage to the coating of internally coated pipes, or as an electrode for cathodic protection of external power supplies. It is something that you have.

[Brief explanation of the drawing]

FIG. 1 is a plan view of an electrode member according to an embodiment of the present invention, FIG. 2 is a sectional view thereof, and FIG. 3 is an enlarged sectional view of a part of a conduit using the electrode member,
FIG. 4 is a perspective view showing another embodiment of the present invention, and FIG.
The figure is a cross-sectional view showing an example of the use of the embodiment shown in Fig. 4;
The figure is a sectional view of a Victory type connector according to still another embodiment of the present invention. DESCRIPTION OF SYMBOLS 1, 11... Electrode member, 2, 12, 24... Seal material, 3, 13, 26... Electric conductor, 3A, 13A, 2
6A...liquid exposed outcrop, 4, 14, 26B...external terminal.

Claims (1)

[Scope of Claims] 1. A wetted outcrop made of an electrical conductor is provided on the inner surface of an insulating sealing material attached to a connecting part of a pipe, and the wetted outcrop is formed by an electrical conductor sealed in the sealing material. An electrode member for supplying electricity to a liquid in a conduit, characterized in that electrical conduction extends to the outer peripheral end face of a sealing material. 2. The electrode member for energizing a liquid in a conduit according to claim 1, wherein the sealing material is a flange connection gasket. 3. The electrode member for energizing a liquid in a conduit according to claim 1, wherein the sealing material is a seal ring in a Victorique type connector.