JPS5853751B2 - Method for detecting disconnection of anode conductor in cathodic protection can - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a method for effectively detecting disconnection of a plurality of anode conductors stretched inside a can of a hot water boiler, hot water storage tank, etc. in order to protect the inside of the can from electrolytic corrosion. It is related to.

Due to the non-uniform structure of the metal surface, there are countless areas with high potential and areas with low potential. When this comes into contact with water, this potential difference forms a local battery, and the areas with low potential become metal ions and elute in the water. A so-called electrolytic corrosion phenomenon occurs, and the metal gradually corrodes.

In particular, in metal (steel) can bodies such as hot water boilers and hot water storage tanks, it is necessary to effectively inhibit this corrosion in order to prevent deterioration of lifespan and water quality.

Conventionally, small can bodies have been treated with a glass lining inside and a single anode machine has been inserted inside the can body to provide cathodic protection. The principle is that when exposed to water, a current flows from the anode rod to that part, lowering the potential of the high-potential part of the metal surface and eliminating the potential difference with other parts to perform cathodic protection.

However, if the can body is not glass-lined and only a single anode rod is installed, it is difficult to flow a uniform current from this anode rod to the entire inside wall of the can body, and the internal structure is complicated. In the case of a hot water boiler or the like, it is difficult to uniformly flow sufficient current to prevent corrosion over even the smallest parts.

This invention further develops the conventional cathodic protection method, and instead of anode rods, multiple conductive wires such as platinum-plated titanium wires are strung at predetermined positions inside a complex and large steel can that cannot be lined with glass. The purpose of the present invention is to provide a method for detecting disconnection of a conductor in a device in which a positive potential is applied to the conductor so that the current flows uniformly and even in small areas on the inside wall of the can. The purpose of this is to immediately detect wire breakage accidents caused by corrosion protection methods and take immediate action.

Methods for connecting multiple conductors to a DC power supply include connecting each conductor in parallel to the power supply and connecting them in series. If the current is lA, the total current will be ``Io2niA, but the total current in the case of one wire break during parallel connection I' =
(n-1) i A, and the rate of change is JI/I□=(n
-1)/n, and the larger n is, the worse the sensitivity is, which is not appropriate.

Next, if the conductors are connected in series and an ammeter is inserted into the DC power supply, if the mth (m≦n) conductor is disconnected, the total current will change as I' = (m-1) i people. The rate is J,
I/I.

=(m-1)/n, and the swing of the ammeter varies depending on the location of the disconnection, and the closer it is to m or n, the worse the sensitivity becomes, so this is also not appropriate.

Therefore, the present invention has developed the terminal n-th and (
An ammeter A is connected between the (n-1)th conductor wires, and the sensitivity of the ammeter is selected close to the rated value iA of one current, thereby increasing the detection ability.

In other words, even if any of the (n-1)th conductor from the 1st conductor breaks, the swing of ammeter A will be zero, and if the nth conductor breaks, the magnitude of the swing will differ depending on the location of the break. However, if the magnitude of the runout is to be reduced much more than the rated value, it means that the nth conductor is also working sufficiently, and there is no problem in practice.

If an alarm contact material is used as the ammeter, disconnection accidents can be detected by the alarm.

FIG. 2 shows a hot water boiler can according to the present invention, in which 1 is the can body, 2 is for the firebox, 3 is a conductor, 4 is a socket for the conductor, 5 is an external connection wire, 6 is an ammeter, 7 indicates a DC power supply.

According to the present invention, disconnection of a conductor in a method for cathodic protection of a can body by extending a conductor can be detected reliably and with high sensitivity;
This has the effect of protecting the can body without progressing corrosion due to wire breakage.

[Brief explanation of drawings]

FIG. 1 is a wiring diagram showing the principle of the invention, and FIG. 2 is a partially cutaway perspective view showing a can body according to an embodiment of the invention. 1...Can body, 3...Conductor wire, 6...
...Ammeter.

Claims (1)

[Claims] 1. In hot water boilers, hot water storage tanks, etc., in which multiple conductive wires are installed as anti-corrosion electrodes inside the metal can, these multiple conductive wires are connected in series to a DC power source, and the terminals of the same DC power source are connected in series. A method for detecting disconnection of an anode conductor in a cathodic protection can, characterized by inserting an ammeter at the conductor connection part and detecting the presence or absence of disconnection based on the deflection of the ammeter.