JP2000303195A - Automatic control circuit of electrolytic protection - Google Patents

Abstract

PROBLEM TO BE SOLVED: To safely and surely execute electrolytic protection for a long period of time by switching to a circuit which directly inputs a protective potential to a comparison terminal of a comparator or inputs the same to the comparison terminal of the comparator by switching of a timer relay, in switching of protective energization to a protective electrode by a relay controller. SOLUTION: A timer 4 repetitively operates a timer relay 5 by a duty ratio of a long time and a short time, executes the protective energization at the time of the long time, stops the energization at the time of the short time, measures the protective potential and executes potential comparison. If the protective potential is higher than a reference potential 31 at the time of the protective potential comparison, the control relay 7 operates to stop the energization and, thereafter, even if the switching contact of the timer relay 5 changes over to the protective energization side, the comparison of the protective potential is continued and the protective energization is not executed. When, however, the protective potential falls below the reference potential 31 before the next protective potential comparison by the timer relay 5, the comparator 1 reacts immediately and activates the control relay 7, thereby starting the protective energization.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an anticorrosion apparatus using an external power supply, which measures the potential of a surface to be anticorrosion so that the anticorrosion current does not become excessive or insufficient, and makes a comparator of an automatic control circuit optimally apply the anticorrosion protection in advance. The present invention relates to a circuit for setting an anticorrosion potential, controlling an anticorrosion current based on this potential, and always obtaining a constant anticorrosion effect.

[0002]

2. Description of the Related Art In an electrolytic protection method in which an external power supply is provided and energized, an anticorrosion effect is evaluated based on a value of an anticorrosion potential obtained by the anticorrosion energization. Therefore, conventionally, it was necessary to determine the effect of the cathodic protection by some method. In general-purpose small-sized anti-corrosion devices that are generally used, the measurement of the anti-corrosion potential has been hardly performed continuously. This is because there is no space for installing a measurement electrode for measuring the potential, and the measurement device for continuous measurement is more expensive than the anticorrosion power supply device. In particular,
For corrosion prevention on the inner surface of a water pipe, the iron ion concentration is analyzed and determined by water quality analysis after energization, and in hot water storage tanks, etc., the water contact area in the tank, the tank material,
Set the current value to obtain the appropriate anticorrosion potential in consideration of water quality, etc., manage the current value with the ammeter attached to the power supply,
Several months later, the tank was drained and evaluated based on the results of a visual inspection. Outside of this, there is a method in which a measurement electrode is protruded from an inner surface of a tank for potential measurement, and a corrosion prevention current is manually adjusted to an appropriate potential while measuring a corrosion prevention potential with a digital voltmeter.

[0003]

However, such a conventional method has a problem in a method of measuring the anticorrosion effect. As an example, considering a method of countermeasures against red water of tap water, a wire electrode for cathodic protection is inserted into a water pipe and energized so that the anticorrosion potential becomes an appropriate potential. As a result, even if the red water is stopped, if the current is not continued, the generation of the red water is encountered again, so the current must be continued. However, as an energization method for maintaining an appropriate potential for a long period of time, energization with a constant-voltage power supply is difficult and dangerous with achieving the purpose. For example, it is necessary to adjust the amount of anti-corrosion energization appropriate for changes during running water and when water is stopped.If continuous energization is performed without replacing water for a long period of time, calcareous deposits grow in the pipe. This causes problems such as blockage of the inside of the pipe and generation of gas due to decomposition of water. In particular, it is extremely dangerous to continuously energize an anticorrosion target having a small area such as a small-diameter pipe. In the case of large containers such as hot water storage tanks, energization is performed so that an appropriate potential is obtained. After a certain period of time, the anticorrosion effect is evaluated by water drainage inspection. There was a drawback that it was not possible to judge. Compared to these methods, if the measuring electrode is protruded from the tank inner surface and energized by a digital voltmeter so as to have an appropriate anticorrosion potential, the anticorrosion effect is maintained and there is no need for visual inspection. The anti-corrosion effect is an evaluation around the measuring electrode, it is difficult to grasp the condition of the entire tank, it is difficult to ensure accuracy, and if water is not drained in the state of non-use, if continuous electricity is supplied, it will be over-corrosive, As described above, growth of deposits, generation of gas, and the like occur, which is extremely dangerous. Both of the above methods require manual maintenance and are inconvenient and not a complete method, and the anticorrosion target surface can always be maintained at an appropriate anticorrosion potential even when the environment changes, especially in the case of tap water. It was necessary to improve such an energizing method. The present invention has been made in view of the above points, and provides an automatic control circuit for performing a potential measurement with a simple configuration and energizing control associated therewith, and which is safe and reliable for long-term use. (See Japanese Patent Application Laid-Open No. H5-24235).

[0004]

FIG. 1 is a circuit diagram of an automatic control circuit for cathodic protection according to the present invention. In FIG. 1, reference numeral 6 denotes a power supply circuit, 8 denotes an anticorrosion container, 9 denotes an anticorrosion electrode, and 10 denotes a measurement electrode. Electrodes, each electrode is insulated in 8 containers, 1 is a comparator, has two comparison terminals 101 and 102, 2 is a constant power source, and 3 is a potentiometer, ideal for anticorrosion Potential and set the potential to the reference potential 31
The anticorrosion potential from the measuring electrode 10 is input to the comparison terminal 102 of the comparator 1, and the other comparison terminal 101 is connected to the output side of the comparator 1 by comparing the potential. 2-pole switching type control relay 7
Control. Reference numeral 4 denotes a timer, which switches the two-pole switching type timer relay 5 alternately and continuously according to the long and short duty ratios. Thus, the fixed contacts 501 and 502 are switched, and the input to the comparison terminal 101 is switched. The control relay 7 switches the input to the anticorrosion electrode 9 by opening and closing with the fixed contact 72 by the switching contact 73, and connects the timer relay 5 to the switching contact 503 or the fixed contact 701 by another switching contact 703. Thus, whether the signal is directly input to the comparison terminal 101 of the comparator 1 is switched. Timer relay 5 when measuring anti-corrosion potential
The switching contact 530 moves to the fixed contact 510 side and the energizing circuit is cut off, and the other switching contact 503 is the fixed contact 501.
, And the anticorrosion potential is input to the comparison terminal 101. The potential is compared with the reference potential 31. If the anticorrosion potential is low, the control relay 7 of the comparator 1 does not operate, and the movable contact 73 of the control relay 7 continues to be connected to the fixed contact 72, and is connected to the anticorrosion electrode 9. And the other switching contact 70 at the same time
3 also maintains the connection with the fixed contact 702, and the anticorrosion potential measured by the measurement electrode 10 via the movable contact 503 of the timer relay 5 and the fixed contact 501 is applied to continue the measurement. Next, when the timer relay 5 is switched to the energized side by the duty ratio, the switching contact 530 is connected to the fixed contact 520 and the anticorrosion energization is performed by the power supply circuit 6. When the compared anti-corrosion potential is higher than the reference potential 31, the control relay 7 connected to the comparator 1 is operated, and the switching contact 73 of the control relay 7 shifts to the fixed contact 71 side to cut off the energizing circuit. The switching contact 703 is connected to the fixed contact 701, is directly input to the comparison terminal 101 of the comparator 1, and continues the comparison of the anticorrosion potential in a state where the power supply is stopped. In the figure, reference numeral 103 denotes a PNP transistor which is controlled by the output of the comparator 1 and activates the control relay 7 by a collector current.

FIG. 2 is a circuit diagram in which the anticorrosion electrode 91 and the measurement electrode are used in common, and the timer relay 51 and the control relay 71 are of a single-pole switching type. 513 is operated, and the fixed contact 512 connected to the power supply circuit 6 and the fixed contact 511 on the input side of the comparison terminal 101 are alternately and continuously switched. The control relay 71 of the comparator 1 is connected to the comparison terminal 1
Operates with the potential compared by 01 and 102. At the time of measuring the anticorrosion potential, if the anticorrosion potential is lower than the reference potential 31, the control relay 71 does not operate, and the switching contact 713 of the control relay 71 continues to be connected to the fixed contact 712 to maintain an energized circuit. If the measured corrosion prevention potential is higher than the reference potential 31, the control relay 71 is activated,
The switching contact 713 is connected to the fixed contact 711, is directly input to the comparison terminal 101 of the comparator 1, and the measurement of the anticorrosion potential is maintained.

FIG. 3 is a circuit diagram having a dummy power supply 11 set to a potential higher than the reference potential, in which a timer relay 52 and a control relay 72 are of a two-pole switching type. 4, the switching contact 523 of the timer relay 52 switches the connection with the power supply circuit 6 and the other switching contact 526 connects the anti-corrosion electrode 91 with the fixed contact 524 or the dummy power supply 11 with the other fixed terminal 525. The connection to the anode is switched, and the switching terminal 526 is connected to the comparison terminal 101 of the comparator 1. At the time of the potential comparison, the switching contact 523 of the timer relay 52 shifts to the fixed contact 521, the connection with the power supply circuit 6 is disconnected, the other switching contact 526 shifts to the fixed contact 524 side, and the switching contact of the control relay 72 changes. 723 and the anticorrosion electrode 91, and the anticorrosion potential is input to the comparison terminal 101 of the comparator 1 by the electrode 91. If the compared potential is lower than the reference potential 31, the control relay 72 does not operate, and the switching terminal 723 of the relay 72 becomes the fixed terminal 722.
Stay connected with.

According to the duty ratio, the timer relay 5
When the second switching contact 523 moves to the fixed contact 522 side,
The power supply circuit 6 is connected and the fixed contact 72 of the control relay 72 is
2, the anticorrosion electrode 91 is energized via the switching contact 723, and at the same time, the other switching contact 526 of the timer relay 52 also moves to the fixed contact 525 side, and the input to the comparison terminal 101 of the comparator 1 is cut off. Although the fixed terminal 525 is connected to the anode of the dummy power supply 11, the cathode side of the power supply is open, so that the potential of the dummy power supply 11 is not input to the comparison terminal 101. When comparing the potentials, if the compared potential is higher than the reference potential 31, the control relay 72 is activated, and the switching contact 723 of the relay 72 is set to the fixed contact 72.
Then, the switching to the power supply circuit 6 is cut off, and at the same time, the other switching contact 726 is connected to the fixed contact 724 to ground the cathode of the dummy power supply 11. Since the switching contact 723 is directly connected to the anticorrosion electrode 91, the anticorrosion potential from the electrode 91 is input to the comparison terminal 101 of the comparator 1 via the fixed contact 524 and the switching contact 526 of the timer relay, and the potential is compared. Continue. When the switching contact 523 of the timer relay 52 shifts to the fixed contact 522 side due to the duty ratio of the relay 4, the switching contact 523 of the control relay 72 is shifted to the fixed contact 721 side, although the power supply circuit 6 is connected. The electrode 91 is not energized. At the same time, the switching contact 526 of the timer relay 52 also shifts to the fixed contact 525, and the dummy power supply 11
Since the input is 1, the operation of the control relay 72 is continued, and this state is maintained even if the anticorrosion potential drops below the reference potential. Next, the potential from the anticorrosion electrode 91 is input to the comparison terminal 101 according to the duty ratio of the timer 4, and when the decrease in the potential is compared, the switching contact 72 of the control relay 72 is switched.
3 moves to the fixed contact 722 side, the anticorrosion energizing circuit is restored,
At the same time, the other switching contact 726 also opens the dummy power supply 11.

[0008]

DESCRIPTION OF THE PREFERRED EMBODIMENTS In the present invention, as an electric circuit for automatically controlling cathodic protection, a potential optimum for cathodic protection is set as a reference potential 31 at a comparison terminal 102 of a comparator 1, and a measuring electrode 10 or a corrosive protection electrode is set. The anticorrosion potential measured by the comparator 91 is compared with another comparison terminal 10 of the comparator 1.
1 is a circuit for controlling the anticorrosion energization in comparison with the reference potential 31 to constantly maintain a constant anticorrosion potential and to obtain a stable anticorrosion effect. When measuring the anticorrosion potential, the value of the anticorrosion potential differs between when the anticorrosion energization is performed and when the anticorrosion energization is stopped and the anticorrosion potential is measured. Therefore, there is a disadvantage in performing the automatic control by comparing the anticorrosion potential, which changes depending on the presence or absence of the anticorrosion energization, with the reference potential 31. Measurements need to be made. In FIG. 1, the timer 4 repeatedly activates the timer relay 5 with a long time and a short time duty ratio, conducts anticorrosion energization for a long time, stops energization for a short time, simultaneously measures anticorrosion potential, and compares the potential. Do.

At the time of comparing the anticorrosion potential, if the anticorrosion potential is higher than the reference potential, the control relay 7 is activated to stop the energization, and then the switching contact of the timer relay 5 switches from the anticorrosion potential measurement to the anticorrosion energizing side. Also, the comparison of the anticorrosion potential is continued, and the anticorrosion energization is not performed. However, if the anticorrosion potential falls below the reference potential 31 before the timer relay 5 compares the anticorrosion potential, the comparator 1 immediately reacts and activates the control relay 7 to start the anticorrosion energization. You can do it. FIG. 1 shows an example of a circuit that performs automatic control using the measurement electrode 10 in the hot water storage tank 8 as an anticorrosion container, but the measurement potential is limited to the vicinity of the measurement electrode 10 as described above. Therefore, anti-corrosion energization is performed in consideration of the value of the reference potential 31, and after a lapse of time, the anti-corrosion effect is confirmed, and thereafter, automatic operation by appropriate energization is performed. The electrode 10 for measuring the anticorrosion potential is an application circuit in the case where an electrode independent of the anticorrosion electrode 9 is used, for example, the electrode 10 is also used as an electrode for preventing empty heating. Even in the case of a large container such as a hot water storage tank, the circuits shown in FIGS. 2 and 3 can be applied, and the shape of the container and the like can be freely selected.

FIG. 2 is a circuit diagram in which the anticorrosion electrode 91 and the measurement electrode are used in common, and the timer relay 51 and the control relay 71 are of a single-pole switching type. Although it is excellent in application when it is difficult to install, even if it is applied to a large-sized hot water storage tank or the like, the same operation is possible in principle. In FIG. 2, a timer relay 51 performs anticorrosion energization for a long time, stops energization for a short time, and compares potentials according to the duty ratio of the timer 4. That is, when the timer relay 51 is operated for a long time, the anticorrosion electrode 9 is used.
In a short time, the anticorrosion electrode 91 is used as a potential measurement electrode, and the anticorrosion potential is input to the comparison terminal 101 of the comparator 1 and compared with the reference potential 31, and the control relay 71 controls the anticorrosion energization. The anticorrosion potential is led to be the same as the optimal anticorrosion potential 31. Also, as in FIG. 1, if the anticorrosion potential decreases before the timer relay 51 shifts to the next potential comparison, this potential is applied to the comparison terminal 10 of the comparator 1.
Since it has been input to 1, the control relay 71 is immediately activated and the anticorrosion energization is started.

FIG. 3 is a circuit diagram in which the anticorrosion electrode 91 and the measurement electrode are also used, and the timer relay 52 and the control relay 72 are of a two-pole switching type. When the anticorrosion potential is higher than the reference potential 31, the anticorrosion potential is replaced by the dummy power supply 11 by the control relay 72, the operation of the control relay 72 is maintained by the dummy power supply 11 until the next potential comparison, and the anticorrosion energization is not performed. It is suitable for applications where the anticorrosion potential is stable around the optimum anticorrosion potential value, and when the anticorrosion potential reaches the optimum anticorrosion potential,
It is known that the anticorrosion potential is maintained even by the interval energization. By adjusting the duty ratio of the timer 4 and appropriately selecting the energization time, a secondary effect of power saving also occurs.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment will be described below with reference to FIG. 2 of the accompanying circuit diagram. Reference numeral 6 denotes a power supply circuit for anticorrosion, which uses a commercial power supply, reduces the voltage to a required voltage by a transformer, and provides a double-wave rectified power supply. The anti-corrosion power supply to be used generally uses a pulsating current that has been subjected to both-wave rectification and does not require a smoothing circuit using a capacitor or the like. In addition, a power supply for the comparator 1 is required, and is supplied by another winding of the transformer. Although it is a single power supply of 5V, it is a general power supply and is omitted because it is not directly related to this circuit. Reference numeral 4 denotes a timer, which oscillates with a duty ratio of a long time and a short time by an IC dedicated to the timer. Then, the drive coil of the timer relay 51 is excited. In this embodiment, one hour is set as a long time, anticorrosion energization is performed, and a short time is set to 5 seconds, and the anticorrosion potential is compared by a comparator. Zero, the contact uses a break contact,
It is excited only for a short time and becomes a make contact. All relays use transfer contacts. 1 is a comparator using a dedicated IC, 2 is a constant power supply for the reference potential 31, which uses the power supply of the comparator IC, is stabilized by a zener diode, and takes out a voltage which becomes the reference potential 31 by a 3 potentiometer. 1 comparison terminal 102. In this embodiment, a water pipe is targeted, and the anticorrosion optimum potential of the water pipe is 2,000.
A reference potential 31 is set to 0 mV, a reference numeral 103 denotes a PNP transistor, and a comparator 1 controls the control relay 7.
1 is operated. 91 is an anticorrosion electrode, which is a commercially available product for electrolytic protection. The material is a platinum-plated titanium wire. The wire electrode 91 is covered with a material. This electrode 9
The voltage supplied to 1 was set to 3 V, and a constant voltage power supply was used at first. However, it was not necessary to use a constant voltage for practical purposes. This is because the circuit corresponds. The anticorrosion current to be supplied depends on the value of the supplied voltage and the conditions of the anticorrosion electrode serving as a load, but since it is accurately controlled by the automatic control circuit of the present invention, it is not necessary to strictly define the current value, In this embodiment, the current was about 10 mA. The implementation target was an apartment building approximately 20 years after construction. The state of red water generation was confirmed, a wire electrode was installed in the water pipe, and continuous energization was performed for two months. The generation stopped, and no red water was generated thereafter. After the energization, when the anticorrosion potential reaches the set value of 2,000 mV, the anticorrosion energization is stopped, and when it falls below 2,000 mV, the energization is started again,
When the above operation was repeated and the continuous operation was performed, when the anticorrosion potential reached about 2,000 mV, this potential was maintained fairly stably, and the time for the anticorrosion energization was gradually reduced, depending on the variation of the water flow. Tended to be. Also in tap water,
Even for a long period of non-use, the power supply was automatically controlled, maintaining an appropriate anticorrosion potential, indicating the effect of automatic control. FIG. 1 shows a circuit for performing automatic control in an anticorrosion power supply device having an anticorrosion electrode and an anticorrosion potential measuring electrode. FIG. 3 has a dummy power supply 11 in the circuit, and when the anticorrosion potential reaches a reference potential. FIG. 4 is a circuit diagram of automatic control for performing stable control even when a dummy power supply is replaced with an anticorrosion potential and fluctuations in the anticorrosion potential. In the present embodiment, the automatic control of the cathodic protection mainly for the purpose of countermeasures against red water in the water pipe is described with reference to FIG. 2. It is intended for the operation of automatic control of the entire device using electrodes. Also, it is known that the sterilization effect is generated by applying a weak current to water in the past.In the case of anticorrosion current in a narrow pipe such as a water pipe, the current density per unit is high, and it is continuous for a long time. There is also a secondary effect of the bactericidal action of the present invention, which can be energized and operated.

[0010]

As described above, according to the present invention, the automatic control of the cathodic protection can be controlled stably and reliably for a long period of time with a very simple circuit configuration and without human intervention. It is very important.

[Brief description of the drawings]

FIG. 1 is a circuit diagram of an automatic control circuit for cathodic protection according to the present invention.

FIG. 2 is a circuit diagram which also serves as an anticorrosion electrode and a measurement electrode.

FIG. 3 is a circuit diagram in which a dummy power supply is provided in the circuit.

[Explanation of symbols]

 Reference Signs List 1 comparator 2 constant power source 3 potentiometer 4 timer 5 timer relay 51 timer relay 52 timer relay 6 power supply circuit 7 control relay 71 control relay 72 control relay 8 anticorrosion container 81 anticorrosion container 9 anticorrosion electrode 91 anticorrosion electrode 10 measurement electrode 101 comparison terminal 102 comparison Terminal 103 Transistor Other three digits are the contacts of each relay

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[Procedure amendment]

[Submission date] April 21, 1999 (1999.4.2
1)

[Procedure amendment 2]

[Document name to be amended] Statement

[Correction target item name] Claim 3

[Correction method] Change

[Correction contents]

[Procedure amendment 3]

[Document name to be amended] Statement

[Correction target item name] 0002

[Correction method] Change

[Correction contents]

[0002]

2. Description of the Related Art In an electrolytic protection method in which an external power supply is provided and energized, an anticorrosion effect is evaluated based on a value of an anticorrosion potential obtained by the anticorrosion energization. Therefore, conventionally, it was necessary to determine the effect of the cathodic protection by some method. In general-purpose small-sized anti-corrosion devices that are generally used, the measurement of the anti-corrosion potential has been hardly performed continuously. This is because there is no space for installing a measurement electrode for measuring the potential, and the measurement device for continuous measurement is more expensive than the anticorrosion power supply device. In particular,
For corrosion prevention on the inner surface of a water pipe, the iron ion concentration is analyzed and determined by water quality analysis after energization, and in hot water storage tanks, etc., the water contact area in the tank, the tank material,
Set the current value to obtain the appropriate anticorrosion potential in consideration of water quality, etc., manage the current value with the ammeter attached to the power supply,
Several months later, the tank was drained and evaluated based on the results of a visual inspection. In the outer, the measuring electrode for potential measurement projecting from the inner surface of the tank, the manual method of the protection current <br/> adjusted so that the proper voltage while measuring the corrosion potential in part by the digital voltmeter Is being done.

[Procedure amendment 4]

[Document name to be amended] Statement

[Correction target item name] 0003

[Correction method] Change

[Correction contents]

[0003]

However, such a conventional method has a problem in a method of measuring the anticorrosion effect. As an example, considering a method of countermeasures against red water of tap water, a wire electrode for cathodic protection is inserted into a water pipe and energized so that the anticorrosion potential becomes an appropriate potential. As a result, even if the red water is stopped, if the current is not continued, the generation of the red water is encountered again, so the current must be continued. However, as an energization method for maintaining an appropriate potential for a long period of time, energization with a constant-voltage power supply is difficult and dangerous with achieving the purpose. For example, the time of running water at a suspension of water supply is needed adjustments proper corrosion protection current amount according to the change, also for continuous energization in the state replacement absence of over water a long period of time, deposits of calcareous growth in the pipe This may cause problems such as blockage of the inside of the pipe or generation of gas due to decomposition of water. Particularly, continuous energization of a small-diameter pipe having a small area, such as an anticorrosion target, is extremely dangerous. In the case of large containers such as hot water storage tanks, energization is performed so that an appropriate potential is obtained. After a certain period of time, the anticorrosion effect is evaluated by water drainage inspection. There was a drawback that it was not possible to judge. Compared to these methods, if the measuring electrode is protruded from the tank inner surface and energized by a digital voltmeter so as to have an appropriate anticorrosion potential, the anticorrosion effect is maintained and there is no need for visual inspection. The anti-corrosion effect is an evaluation around the measuring electrode, it is difficult to grasp the condition of the entire tank, it is difficult to ensure accuracy, and if water is not drained in the state of non-use, if continuous electricity is supplied, it will be over-corrosive, As described above, growth of deposits, generation of gas, and the like occur, which is extremely dangerous. Both of the above methods require manual maintenance and are inconvenient and not a complete method, and the anticorrosion target surface can always be maintained at an appropriate anticorrosion potential even when the environment changes, especially in the case of tap water. It was necessary to improve such an energizing method. The present invention has been made in view of the above points, and provides an automatic control circuit for performing a potential measurement with a simple configuration and energizing control associated therewith, and which is safe and reliable for long-term use. (See Japanese Patent Application Laid-Open No. H5-24235).

Claims (3)

[Claims] 1. A two-pole switching timer relay 5 having an anticorrosion electrode 9, a measurement electrode 10 and a power supply circuit 6 and operated by a timer 4 having a long and short duty ratio, and a potential optimal for anticorrosion. The reference potential 31 is set at the comparison terminal 102 of the comparator 1 and includes a two-pole switching type control relay 7 operated by the comparator 1. Switching of whether to input the anticorrosion potential to another comparison terminal 101 of the comparator 1 is performed, and switching of the anticorrosion energization to the anticorrosion electrode 9 by the control relay 7 and direct input of the anticorrosion potential to the comparison terminal 101 of the comparator 1. Or the switching of the timer relay 5 causes the comparison terminal 1 of the comparator 1
Automatic control circuit of cathodic protection that switches to the circuit to be input to 01. 2. The anticorrosion electrode 91 and the measurement electrode are also used,
In a circuit in which the timer relay 51 and the control relay 71 are of a single-pole switching type, the anticorrosion electrode 91 is provided by the timer relay 51 operated by the timer 4 having a duty ratio.
Switch between the protection corrosion energization and the direct input of the corrosion protection potential to the comparison terminal 101 of the comparator 1.
2. The automatic control circuit for electrolytic protection according to claim 1, wherein the switching of whether the protection electrode is applied to the protection electrode or whether the protection potential is directly input to the comparison terminal of the comparator is performed by the switch. 3. A circuit having a dummy power supply 11 in a circuit, a timer relay 52 and a control relay 72 are of a two-pole switching type, and a timer relay 52 operated by a timer 4 having a duty ratio is used to switch the anticorrosion energization to the anticorrosion electrode. The connection between the comparison terminal 101 of the comparator 1 and the dummy power supply 11 or the connection of the anticorrosion electrode 91 is performed.
3. The automatic control system according to claim 1, wherein the circuit is switched, and the anticorrosion electrode 91 connects the switching terminal 723 of the control relay 72 and the fixed terminal 524 of the timer relay 52.