JPS58216968A - Method for detecting quality of insulation coating of reference electrode cable in electrolyte - Google Patents

Abstract

PURPOSE:To make it possible to simply judge the quality of the insulation coating of a reference electrode cable, by a method wherein the inner conductor of a coaxial cable is connected to a reference electrode in an electrolyte and an outer conductor is further provided to the outside of the inner conductor through an insulating substance to measure potential difference between the inner and the outer conductors. CONSTITUTION:A coaxial cable 2 consisting an inner conductor 2a, an internal insulating coating 2b, an outer conductor 2c and an external insulating coating 2d is connected to a reference electrode through the inner conductor 2a at one end thereof and, when the external insulating coating 2d of the coaxial cable 2 in an electrolyte 3 is damaged, the external conductor 2c is connected to the electrolyte through the damaged part 2e and potential difference between a different kind of metals is generated between the external conductor 2c and the reference electrode 1, that is, the internal conductor 2a.

Description

[Detailed description of the invention] The present invention relates to a method for detecting the quality of insulation coating.

The reference electrode used to measure the potential difference with a metal body in an electrolyte such as soil, seawater, or water is made of saturated copper, saturated copper tetraate, silver chloride, etc.; A core cable is connected, which passes through the electrolyte and connects to a measuring device at an external location.

Note that the connection portion of the cable to the reference electrode is insulated so that the cable conductor (core wire) does not come into contact with the electrolyte.

Generally, the insulation sheath of a cable is damaged over time due to various causes, but the insulation sheath of a cable in an electrolyte is particularly susceptible to damage and must be periodically inspected.

However, to check the quality of the cable in the electrolyte,
Since the cable has to be pulled out from the electrolyte together with the reference electrode, there is a problem in that the work is complicated and time-consuming and requires a large number of workers.

The present invention is intended to solve such conventional problems, and an example of its implementation will be described below with reference to the drawings.

In Fig. 1, ■ is a reference electrode, and this reference electrode 1
An inner conductor 2a at one end of a coaxial cable 2 consisting of an inner conductor 2a, an inner insulating sheath 2b, an outer conductor 2c, and an outer insulating sheath 2d is connected to the inner conductor 2a.

It is assumed that the outer conductor 2C of the coaxial cable 2 at the connection part with the reference electrode &1 is insulated so as not to come into contact with the reference electrode 1 and the outside (electrolyte).

As shown in FIG. 2, if the outer insulation coating 2d of the coaxial cable 2 in the electrolyte 3 is damaged for some reason, the outer conductor 2
C comes into contact with the electrolyte 3, and a so-called potential difference between different metals (several 1.00 mV) is generated between the conductor 2C and the reference electrode 1.

Moreover, when the outer conductor 2C comes into contact with the electrolyte 3 through the damaged part 2e, the outer conductor 2c and the reference electrode 1 contact each other via the electrolyte 3.
It becomes a finite resistance with a gap.

Therefore, by connecting a measuring device 4 such as a voltmeter or a resistance meter between the inner conductor 2a and the outer conductor 20 at the other end of the coaxial cable 2 outside the electrolyte 3, it is possible to 5) It is possible to completely detect that 2d is damaged.

Furthermore, if the outer insulation coating 2d and the inner insulation coating 2b of the coaxial cable 2 in the electrolyte 3 are damaged at the same location,
Alternatively, if the electrolyte 3 is infiltrated due to breakage at a different location, a low resistance or a short circuit occurs between the outer conductor 2C and the inner conductor 2a via the electrolyte 3.

Therefore, by connecting a measuring device 4 (resistance meter) between the inner conductor 2a and outer conductor 2C at the other end of the coaxial cable 2 outside the electrolyte 3, it is possible to It is possible to completely detect that the insulation coating 2b is damaged.

In this case, there is a low resistance or a short circuit between the outer conductor 2C and the inner conductor 2a, so the potential difference between the outer conductor 2C and the reference electrode 1 is extremely small or small.

Note that even if the internal insulation coating 2b of the coaxial cable 2 in the electrolyte 3 is damaged, if the external insulation coating 2d is damaged, no potential difference will occur between the outer conductor 2C and the reference electrode 1. Since the resistance between the outer conductor 2C and the reference electrode 1 is infinite, the pointer of the measuring device i such as a voltmeter or ohmmeter does not swing.

As described above, according to the present invention, the potential difference or the presence or absence of continuity between the inner conductor and the outer conductor at the other end of the coaxial cable outside the electrolyte is measured without pulling out the cable together with the reference electrode from inside the electrolyte as in the conventional method. By this extremely simple process, it is possible to detect individual damage to the outer insulation sheath of a coaxial cable in electrolyte or combined damage to the outer insulation sheath and inner insulation sheath.

[Brief explanation of drawings]

The figures show an example of the implementation of the present invention, and FIG. 1 is a schematic diagram of an embodiment in which a coaxial cable is connected to a reference electrode, and FIG.
The figure is an explanatory diagram showing a detection situation when the insulation coating of a coaxial cable in an electrolyte is damaged. Figure 1 Figure 2 1゜

Claims (1)

[Claims] Connect the inner conductor of the coaxial cable to the reference electrode for measuring the potential difference with a metal object in the electrolyte, and insulate the outer conductor of the coaxial cable at this connection so that it does not come into contact with the reference electrode or the electrolyte, and expose it to the outside of the electrolyte. A method for detecting the quality of an insulation coating of a reference electrode cable in an electrolyte, the method comprising measuring the potential difference or the presence or absence of continuity between an inner conductor and an outer conductor of the coaxial cable.