JP2000218272A - Aquatic organism-contamination preventing device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To simplify a circuit structure and to improve power efficiency in a device for electrochemically releasing an aquatic organism depositing on an underwater structure, or the like, by switching a potential exerted on a working electrode by a switch part formed by combining the circuits connecting diodes in the opposite direction to each other to the switches in parallel. SOLUTION: This contamination preventing device is so constituted that the potential of a working electrode is made positive or negative with respect to a reference electrode by using only a positive power source. A reversal- nonreversal switching circuit 7 for impressing a PWM-controlled pulse for the difference from the absolute value of a desired voltage through a voltage output circuit is provided in the controller of such a device. The output of a source voltage is turned on or off in accordance with the PWM-controlled pulse by the switching circuit 7 through an FET 9, and a switch part formed by combining the circuits connecting diodes 12 and 13 in the opposite direction to each other to the respective switches 14 and 15 through a capacitor 11 in parallel is provided.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an antifouling device for preventing adhesion of aquatic organisms in water.

[0002]

2. Description of the Related Art In recent years, there has been proposed a method of electrochemically controlling aquatic organisms adhering to the surface of an underwater structure or an object in contact with water without generating harmful substances such as chlorine. For example, JP-A-4-341392 discloses that
By the potentiostat, +0 to +1.5 V vs. 1.5 is applied to the conductive antifouling surface. Applying a positive potential of SCE to sterilize the attached aquatic organisms;
s. An antifouling method comprising a phase in which a negative potential of SCE is applied to detach attached aquatic organisms is disclosed. Japanese Unexamined Patent Publication No. 4-289309 discloses an antifouling method in which a potentiostat is operated at a predetermined cycle by a function generator to change the potential of a conductive antifouling surface. Japanese Patent Application No. 10-29 filed by the applicant of the present application
No. 2881 discloses a method of realizing the same operation as above using only a positive power supply using an FET bridge.

[0003]

SUMMARY OF THE INVENTION The above-mentioned Japanese Patent Application Laid-Open No. 4-34 is disclosed.
No. 1392, Japanese Unexamined Patent Publication No. 4-289309,
Using a three-electrode potentiostat, which is a well-known technique of electrochemical measurement, cells of aquatic organisms are sterilized, and adhered cells and their decomposed products are treated with a conductive substrate (three-electrode) that is an antifouling surface. Working electrode) can be desorbed from the surface. However, when the potentials of the working electrode and the reference electrode are 1.5V-
In order to apply a potential to the working electrode and the counter electrode so as to be in the range of 0.4 V, both a positive power supply and a negative power supply were required as power supplies to the working electrode and the counter electrode. Also, in Japanese Patent Application No. 10-292881 filed by the applicant of the present application, the circuit is slightly complicated because an FET bridge is used, and the power supply may be only positive. The power efficiency was not very good due to the separate parts.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and provides a positive electrode and a negative potential between a working electrode and a counter electrode to provide a reference electrode disposed between the working electrode and the counter electrode. The potential of the working electrode is measured by subtracting the potential of the reference electrode from the measured potential of the working electrode, and a means for preventing aquatic organisms having means for changing the potential applied between the working electrode and the counter electrode based on the result of the calculation. In the fouling device, the magnitude of the potential applied to the working electrode is controlled by pulse width modulation, and the polarity of the potential applied to the working electrode is controlled by using a switch in which a circuit in which diodes and switches connected in opposite directions are connected in parallel is used. The present invention proposes an aquatic organism antifouling device having means for switching between the two.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The aquatic organism antifouling device according to the present invention prevents the adherence of aquatic organisms by repeating a phase for sterilizing the attached aquatic organisms and a phase for removing the sterilized aquatic organisms. In the phase that sterilizes the aquatic organisms that adhere to it, the positive electrode is controlled by PWM (pulse width modulation) and a switch unit in which circuits in which opposite diodes are connected to switches are connected in parallel with the counter electrode as a ground electrode. , Applying a positive potential to the working electrode, measuring the potential of the reference electrode and the potential of the working electrode disposed between the working electrode and the counter electrode,
The potential of the working electrode is controlled so that the potential of the working electrode with respect to the reference electrode becomes a target potential between +0 and +1.5 V. On the other hand, in the phase for desorbing the sterilized aquatic organism, a negative potential is applied to the working electrode by the same control, and the potential of the working electrode with respect to the reference electrode becomes the target potential between -0 to -0.4 V. The potential of the working electrode is controlled as described above.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS The details of the present invention will be described below with reference to the accompanying drawings. FIG. 1 is an overall electric block diagram, FIG. 2 is a timing chart, FIG. 3 is an electric internal block diagram of a switching circuit for non-inversion / inversion of an output voltage, and FIG. 4 shows pulses controlled positively and negatively.

The data processor 1 shown in FIG. 1 determines a timing chart of the set value of the potential of the working electrode 3 with respect to the reference electrode 2 and sets the potential of the working electrode 3 with respect to the reference electrode 2 at that time according to the timing chart. The value is transmitted to the CPU 4. The CPU 4 controls the potential applied to the working electrode 3 so that the potential of the working electrode 3 with respect to the reference electrode 2 becomes the received potential.

Next, the timing chart shown in FIG. 2 will be described in detail. The horizontal axis represents time, and the vertical axis represents the potential that the working electrode 3 should take with respect to the reference electrode 2. The timing chart has the following four phases in order on the time axis. T
In one phase, a positive potential is applied to the working electrode 3 with respect to the reference electrode 2,
The aquatic organisms attached to the working electrode 3 are sterilized. In the T2 phase, the sterilization is stopped. In the T3 phase, a negative potential is applied to the working electrode 3 with respect to the reference electrode 2, and sterilized aquatic organisms attached to the working electrode 3 are eliminated. In the T4 phase, desorption is stopped. By performing these four phases in order and repeating the cycle,
Prevents aquatic organisms from attaching.

The CPU 4 is connected to a ROM 5 and a RAM 6 for holding programs, data, works and the like, and operates in accordance with programs stored in the ROM 5. The CPU 4 receives the set value of the potential to be taken by the working electrode 3 with respect to the reference electrode 2 from the data processing unit 1, and if the set value of the potential is positive, determines that it is the T1 phase for performing sterilization. On the other hand, if the received set value of the potential is negative, it is determined that the phase is the T3 phase for desorption. If the set value of the received potential is 0, it is determined that the potential is the T2 phase or the T4 phase. In the case of the T1 phase or the T3 phase, the working electrode 3 is set so that the potential of the working electrode 3 with respect to the reference electrode 2 becomes a set value accordingly.
Is controlled.

Next, a method of applying a potential to the working electrode 3 so that the potential of the working electrode 3 with respect to the reference electrode 2 becomes a positive or negative potential using only a positive power supply will be described with reference to FIGS. 3 and 4. Will be explained. FIG. 3 is an electrical block diagram of the inversion / non-inversion switching circuit 7. As will be described later, the voltage output circuit 8 responds to a difference between the target voltage and the absolute value of the voltage. P
The WM-controlled pulse is output to the inversion / non-inversion switching circuit 7. The output from the voltage output circuit 8 is connected to the power supply 10 through the FET 9 and the output of the power supply voltage is
Turn on / off according to controlled pulse. The power supply output controlled by PWM is connected to diodes 12 and 13, which are opposite to each other, via a capacitor 1 via a switch 1.
The circuits connected to 4 and 15 are connected to a switch unit in which the circuits are combined in parallel. The value of the capacitor 16 is selected so as to have a sufficiently small impedance to allow a required load current to flow with respect to the frequency of the PWM control. When making the potential of the working electrode 3 positive with respect to the reference electrode 2, the CPU 4 turns on the switch 14 and turns on the switch 15
Turn off. Then, the pulse obtained there is shown in FIG.
As shown in (a), the voltage is shifted to the positive side with respect to the ground potential. To make the potential negative, switch 1
4 is turned off and the switch 15 is turned on. Then, the obtained pulse is shifted toward the negative side with respect to the ground potential as shown in FIG. When these pulses are integrated through an integrating circuit including the coil 17 and the capacitor 16, a positive output voltage or a negative output voltage can be obtained.

A method of controlling the potential applied to the working electrode 3 so that the potential of the working electrode 3 with respect to the reference electrode 2 becomes the target potential will be described with reference to FIG. The arithmetic circuit 18 receives the potentials of the reference electrode 2 and the working electrode 3 and subtracts the potential of the reference electrode 2 from the potential of the working electrode 3 to obtain a working electrode 3 for the reference electrode 2.
Is input to the inversion / non-inversion switching circuit 19. The inverting / non-inverting switching circuit 19 outputs the input potential as it is, or reverses the positive / negative output according to the signal from the CPU 4. In the T1 phase, the CPU 4 outputs the input potential as it is.
In the phase, the inversion / non-inversion switching circuit 19 is controlled so that the polarity of the input potential is inverted and output. Thereby, it is input to the arithmetic circuit 20.

The measured value of the potential of the working electrode 3 with respect to the reference electrode 2 becomes its absolute value. The CPU 4 outputs the absolute value of the target potential to the arithmetic circuit 20 via the D / A converter 21.
The arithmetic circuit 20 calculates the difference between the measured value and the target value, and outputs the difference to the voltage output circuit 8. The voltage output circuit 8 converts the input potential into a PWM waveform by using a triangular wave and outputs the converted waveform.
Similarly to the control of the inverting / non-inverting switching circuit 19, the control is performed such that the PWM waveform is output as it is in the T1 phase, and the PWM waveform is inverted and output in the T3 phase. The voltage output circuit 8 outputs the PWM waveform generated in this way to the inversion / non-inversion switching circuit 7.

[0013]

According to the present invention, only a positive power supply is used, a ground potential is always applied to the counter electrode, and a switch section in which circuits in which diodes opposite to each other are connected to the switches in parallel is turned on / off. By switching, the potential applied to the working electrode is switched between positive and negative, and the magnitude of the potential is changed to PW by utilizing the fact that the input is a rectangular wave.
By the M control, it can be controlled to a target potential between 1.5 V and -0.4 V. Further, the circuit of the inverting / non-inverting switching unit is simplified, and the power efficiency is improved.

[Brief description of the drawings]

FIG. 1 is an overall electrical block diagram

FIG. 2 is a timing chart of output potential and output time.

FIG. 3 is an electrical internal block diagram of an output voltage inversion / non-inversion switching circuit.

FIG. 4 is a diagram of voltage output switched between positive and negative.

[Explanation of symbols]

 Reference Signs List 1 data processing unit 2 reference electrode 3 working electrode 4 CPU 5 ROM 6 RAM 7 inversion / non-inversion switching circuit 8 voltage output circuit 9 FET 10 power supply 11 capacitor 12 reverse diode 13 reverse diode 14 switch 15 switch 16 capacitor 17 coil 18 Arithmetic circuit 19 Inverting / non-inverting switching circuit 20 Arithmetic circuit 21 D / A converter

Claims (1)

[Claims] A positive and negative potential is applied between a working electrode and a counter electrode to measure a potential of a reference electrode and a potential of a working electrode disposed between the working electrode and the counter electrode, and the measured working electrode An operation of subtracting the potential of the reference electrode from the potential, and an anti-fouling device for aquatic organisms having means for changing the potential applied between the working electrode and the counter electrode from the result of the operation, the pulse width modulation of the potential applied to the working electrode An antifouling system for aquatic organisms, comprising means for controlling the size and switching the polarity of the potential applied to the working electrode by using a switch in which a circuit in which diodes and switches connected in opposite directions are connected in parallel is provided. apparatus.