JPS61245000A - Corrosion monitoring method of copper piping - Google Patents

Abstract

PURPOSE:To enable accurate digital detection of the degree of corrosion by incorporating a monitor pipe made of same material in a copper piping system then measuring the potential on the inner face of said monitor pipe thus detecting the degree of corrosion. CONSTITUTION:A monitor pipe 4 incorporated in a copper piping system 1 is removed from the piping system periodically on the inspection day then immersed into a container filled with water taken from said piping system. Then a lead wire 7 is connected to tester 11 while a saturated calomel electrode 12 is connected to the electrode at one side of tester to provide a referential electrode and to measure the differential potential. It has been found that the potential rise on the inner surface due to oxide will cause corrosion of copper piping, thereby it can be known accurately from the potential on the inner face of monitor pipe whether corrosion is starting in the piping system or it is under stable conditions.

Description

DETAILED DESCRIPTION OF THE INVENTION Field of Industrial Application This invention relates to a corrosion monitoring method for copper piping that can quantitatively detect the degree of corrosion in piping systems using steel pipes such as hot water supply piping.

Problems to be Solved by the Invention Conventionally, as shown in FIG. 1, a monitor tube 2 made of the same material is incorporated into a system of copper piping 1 via a flange joint 3, and if necessary, the monitor tube 2 is removed and its inner surface The degree of corrosion was monitored. However, this method relies on visual observation and cannot accurately detect the degree of corrosion based on numerical values.

This invention was made in view of the above circumstances.

The purpose is to accurately detect the degree of corrosion in copper piping numerically and, for example, to determine in advance whether it is necessary to introduce corrosion inhibitors.
The purpose of this invention is to propose a corrosion monitoring method that can prevent water leakage accidents caused by pitting corrosion of copper piping.

A method for monitoring corrosion of copper piping according to the present invention incorporates a monitor tube made of the same material into the copper piping system and measures the potential on the inner surface of the monitor tube to determine the degree of corrosion. It is characterized by detecting.

Figure 2 shows the monitor tube 4 used in this invention, and the main body 5.
is made of copper of the same quality as the copper piping to be installed, and is insulated with a coating layer 6 of Teflon or the like except for the inner surface, and a lead wire 7 is connected to the main body 5 by penetrating the coating layer 6.

FIG. 3 shows this monitor tube 4 installed in a copper piping system 1, connected by flange joints 3, 3, and valves 8, 8 and bypass 9 provided on both sides thereof.

The monitor tube 4 incorporated into the copper piping system 1 is removed from the piping system on the inspection day of a predetermined period, and placed in a container such as a plastic bucket containing water 10 taken out from the piping system as shown in Fig. 4. Soak. Next, connect the lead wire 7 to the tester 11,
A saturated calomel electrode 12 is connected to one pole of the tester to serve as a reference electrode, and the potential difference therebetween is measured.

It is known that corrosion of copper piping is caused by an increase in potential due to oxides on the inner surface. Therefore, it is possible to accurately determine whether a state that causes pitting corrosion or a safe state is determined by the potential of the inner surface of the monitor tube. FIG. 5 shows the potential difference across the inner surface of the monitor tube measured on a given test day. It can be seen that both are in a safe range, lower than the potential that causes pitting corrosion (150 mV). When the pitting corrosion potential is approached, measures are taken to suppress the potential rise, such as injecting anticorrosion chemicals into the piping system.

FIG. 6 is a detailed view of the monitor tube 4 used in this invention. Both ends of the body part 5 are flange-shaped and have enlarged openings, and a flange 13 is attached to the outer surface of the body part 5. An insulating material 14 is inserted between the body part 5 and the flange 13. All of the outer surfaces of the main body 5, except for the inner surface thereof, are covered with a coating layer 6 made of Teflon so as not to come into contact with liquid.

Further, a lead wire 7 is connected to the main body portion 5 by passing through this coating layer 6.

Function/Effect This invention consists of the above configuration. According to this corrosion monitoring method, the degree of corrosion can be accurately detected numerically, and appropriate corrosion prevention measures can be taken for the pipe system. Therefore, the service life of copper piping can be extended and water leakage accidents due to pitting corrosion can be prevented.

[Brief explanation of drawings]

Figure 1 is a side view of a monitor pipe installed in a copper piping system, Figure 43 is a cross-sectional view of the monitor pipe used in this invention and a schematic diagram of the pipe system incorporating the monitor pipe, and Figure 4 is a monitor pipe system. FIG. 5 is a schematic diagram showing the measuring state of the potential of the tube, FIG. 5 is a graph showing the measured potential and pitting potential, and FIG. 6 is a sectional view showing details of the monitor tube. 1...Copper piping, 2...Monitor tube 3...7 lange joint, 4...Monitor tube 5...Main body,
6... Coating layer 7... Lead wire, 8... Valve, 9... Bypass] 0... Water, 11... Tester 12... Saturated calomel electrode, 13... 7 Lunge 14...
Insulating material. Figure 6

Claims (1)

[Claims] (1) A method for monitoring corrosion of copper piping, which comprises incorporating a monitor tube made of the same material into a copper piping system, and measuring the potential on the inner surface of the monitor tube to detect the degree of corrosion.