JP2003026088A - Electric field sensor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To dispense with maintenance work for periodically replacing an internal liquid by eliminating a structure such as projecting from a can body, and a complicated structure by the presence of the internal liquid. SOLUTION: This electric field sensor comprises two chlorine ion solid membrane electrodes 31 and 32 arranged at a specific distance in the can body, a differential amplifier 4 for amplifying and outputting interelectrode voltage generated between the chlorine ion solid membrane electrodes 31 and 32 as a received signal, a timing delaying circuit 5 for outputting a contact point signal 53 for externally outputting a signal outputted by the differential amplifier 4 after passing convergence time of preset drift voltage by counting time when two contact points exposed to seawater are short-circuited by the seawater, a switch 6 operating so as to externally output the signal outputted by the differential amplifier 4 by receiving the contact point signal 53, and a detector 8 for outputting a signal when the signal sent out of the switch 6 becomes a prescribed threshold value or more.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an electric field sensor equipped with an electric field detecting means for detecting a ship which is laid on the seabed and sails / passes over the sea, and more particularly to an electric field sensor which detects a ship using a solid film electrode.

[0002]

2. Description of the Related Art A conventional electric field sensor uses a silver chloride electrode as its electrode. 4 (a), (b),
(C) is a structure of a conventional standard silver chloride electrode shown in JIS-K-0122. This standard silver chloride electrode is composed of a conductive wire 91, a support tube 9 made of glass, epoxy resin, or the like.
2. A reference electrode 93 such as a silver-silver chloride electrode, an internal liquid 94, an ion-sensitive film 95 formed of a glass film, a solid film, a liquid film, etc., an internal liquid 96 of a diaphragm electrode, and a porous plate 97 such as ceramics. It is provided as an element.

The conventional electrodes are shown in FIGS. 4 (a), 4 (b),
As shown in (c), it has a cylindrical structure that uses the internal liquid 94 or the internal liquid 96 of the diaphragm type electrode, and in order to secure the water pressure resistance, a compensator is added to balance the pressure of seawater and the internal liquid. There is a need. Also, conventional electrodes are
In the external structure, it protruded from the electric field sensor can body, making it difficult to handle during laying work.

[0004]

The conventional electric field sensor uses a silver chloride electrode and has the following problems.

The first problem is that, because of the three-dimensional structure in which the internal liquid exists, the electric field sensor according to the prior art has a structure protruding from the electric field sensor can body, which is inconvenient to handle during laying work. This is to eliminate the structure protruding from the electric field sensor can body.

A second problem is that maintenance work for periodically exchanging the internal liquid is required, and this maintenance work is eliminated.

A third problem is to eliminate a complicated structure due to a pressure resistance method such as a compensator in order to balance the pressure with the internal liquid used for increasing the water pressure resistance.

[0008]

In order to solve the above problems, the invention of an electric field sensor according to claim 1 is between a solid type electrode for generating a voltage in contact with seawater, and the solid type electrode. A differential amplifier that amplifies the inter-electrode voltage generated in the solid state electrode, and a time delay circuit in which a convergence time from the occurrence of the drift voltage generated in the solid type electrode to the disappearance thereof is set. To do.

Further, the invention of the electric field sensor according to claim 2 is such that between a plurality of chlorine ion solid membrane electrodes for generating a voltage in contact with seawater and between the electrodes generated between the plurality of chlorine ion solid membrane electrodes. A differential amplifier that amplifies the voltage; and a time delay circuit in which a convergence time from the occurrence of the drift voltage generated between the plurality of chloride ion solid film electrodes to the disappearance thereof is set. And

Further, in the invention of the electric field sensor according to claim 3, when the time delay circuit according to claim 1 or 2 senses seawater, the time is counted, and after the convergence time has elapsed, the difference is detected. It is characterized in that a contact signal for outputting the signal output from the dynamic amplifier to the outside is sent.

Further, the invention of an electric field sensor according to claim 4 is characterized in that the time delay circuit according to claim 1 or 2 comprises two contacts which are short-circuited by seawater.

Further, in the invention of the electric field sensor according to claim 5, the time delay circuit according to claim 1 or 2 activates a timer when detecting the seawater, and the convergence time preset in the timer. After the time elapses, a contact signal for outputting the signal output by the differential amplifier to the outside is transmitted.

Further, in the invention of the electric field sensor according to claim 6, when the value of the signal output by the differential amplifier according to claim 1 or 2 is larger than a preset threshold value, the electric field detection signal is sent. It is characterized by outputting.

Further, the invention of an electric field sensor according to a seventh aspect is such that a plurality of chlorine ion solid film electrodes arranged at a constant distance in a can of the electric field sensor, and the plurality of chlorine ion solid film electrodes. Exposed to seawater and a differential amplifier that amplifies the inter-electrode voltage generated between
When one of the contacts is short-circuited by seawater, the time is counted, and after the preset convergence time of the drift voltage elapses, a time delay that outputs the contact signal for outputting the reception signal output by the differential amplifier to the outside is output. An operating circuit, a switch that operates to receive the contact signal output by the time delay circuit and output the reception signal output by the differential amplifier to the outside, and the reception signal transmitted by the switch. And a detector that outputs an electric field detection signal when the threshold value is equal to or higher than a predetermined threshold value.

Further, in the invention of an electric field sensor according to claim 8, the differential amplifier according to claim 2 or 7 is
It is characterized by further comprising a bandpass filter in which a center frequency is set to a power source frequency of a ship's motor or generator, and a detection circuit for detecting an output from the bandpass filter.

Further, the invention of an electric field sensor according to claim 9 is characterized in that the plurality of chlorine ion solid film electrodes according to claim 2 or 7 have the same area.

Further, the invention of an electric field sensor according to claim 10 is characterized in that the distance between the plurality of chloride ion solid film electrodes according to claim 2 or 7 can be varied.

[0018]

BEST MODE FOR CARRYING OUT THE INVENTION (First Embodiment) The present invention is
An electric field sensor that is laid on the bottom of the sea and uses an electrode to detect the electric field emitted by a navigating ship, and in particular uses a chloride ion solid membrane electrode (that is, a solid type electrode) that does not use an internal liquid as the electrode. I am trying. Furthermore, the electric field sensor of the present invention is characterized by having a time delay circuit that eliminates a malfunction caused by a voltage drift that occurs until the electrode becomes compatible with seawater.

(Description of Configuration of First Embodiment) Next,
The configuration of the first embodiment of the present invention will be described in detail with reference to the drawings. FIG. 1 is a block diagram showing a first embodiment of a chloride ion solid film electrode according to the electric field sensor of the present invention, and FIG. 2 is a chloride ion solid film according to the electric field sensor of the present invention.

The ship 2 is equipped with an electrocorrosion protection device 1 in order to prevent corrosion of the hull. A voltage that cancels the potential that causes corrosion of the hull is applied between the anode 11 and the cathode 12 of the electrocorrosion protection device 1, and a current flows in seawater between the anode 11 and the cathode 12. In seawater, which is an electrolytic solution, the electric current generated by the electric field 21 emitted from the ship 2 is equivalent to the movement of ions.

The chloride ion solid film electrodes 31, 32 are made of Ag.
Cl, Ag2S sparingly soluble silver salt precipitate formed under pressure, or
It is a sintered sensitive film, and no internal liquid is used. A voltage corresponding to the amount of chlorine ions is generated between the chlorine ion solid film electrodes 31 and 32. Particularly, in the electric field sensor 7 of the present invention, the two chloride ion solid film electrodes 31, 32 are arranged at a fixed distance in the electric field sensor can body 71 serving as a casing.

Due to the movement of chlorine ions by the electric field 21, the chlorine ion solid film electrodes 31, 32 cause a difference in the chlorine ion amount due to the distance between the electrodes, and an interelectrode voltage (Vin) 301 is generated due to the difference in the chlorine ion amount. . Voltage between electrodes (Vi
In n) 301, the distance between the electrodes is widened and the difference in the chlorine ion amount increases, so that the amount increases and the detection sensitivity improves.

FIG. 2 is a structural diagram of the chloride ion solid film electrodes 31 and 32. The chlorine ion solid membrane electrodes 31 and 32 are fixed by a polyacetal resin stand 302,
It is connected to the differential amplifier 4 by conductive lines 3001 and 3002. Further, the chlorine ion solid film electrodes 31, 32 are
The areas are equal so that they have the same sensitivity. The chlorine ion solid membrane electrodes 31, 32 are not compatible with seawater when immersed in seawater (that is, foreign matter such as bubbles or dust on the surface of the chlorine ion solid membrane electrodes 31, 32 adheres to them). Therefore, a drift voltage is generated in the inter-electrode voltage (Vin) 301 when the surfaces of the chlorine ion solid film electrodes 31 and 32 are not in stable contact with seawater). The drift voltage decreases with time, and disappears when the chlorine ion solid membrane electrodes 31, 32 are compatible with seawater (that is, the surfaces of the chlorine ion solid membrane electrodes 31, 32 are in stable contact with seawater).

The differential amplifier 4 is a chloride ion solid film electrode 3
The inter-electrode voltage (Vin) 301 generated between 1 and 32 is amplified and output as a reception signal 401.

The time delay circuit 5 counts the time when the electric field sensor 7 enters the seawater and the contacts 51 and 52 (seawater detection sensor) are short-circuited by the seawater, and the preset convergence time of the drift voltage ( That is, the contact signal 53 is output after a lapse of time (from the generation of the drift voltage to the disappearance), the switch 6 is closed (the switch 6 is turned on) by the contact signal 53, and the reception signal 401 is detected by the detector 8 By outputting to, it is possible to prevent erroneous detection due to the drift voltage. In addition, contacts 51, 52 (seawater sensor)
Is short-circuited with seawater, the timer is activated and the contact signal 5 is reached after the preset drift voltage convergence time has elapsed.
It is also possible to output 3.

The detector 8 detects that the received signal 401 has a threshold value (RE
F) When it becomes 802 or more, the detection signal 81 (electric field detection signal) is output.

(Description of Operation of First Embodiment) Next, the operation of the first embodiment of the present invention will be described with reference to FIG.

The electric field sensor 7 is laid in the sea, and the contacts 51 and 52 of the time delay circuit 5 are short-circuited with seawater, so that the time delay circuit 5 counts time. The time delay circuit 5 is set with a time for the drift voltage of the chlorine ion solid film electrodes 31, 32 to settle, and after the drift voltage disappears in the inter-electrode voltage (Vin) 301,
The contact signal 53 is output and the switch 6 is closed.

In the galvanic protection device 1 for a ship 2 passing over the sea surface, an anode 11 and a cathode 12 are provided in order to prevent corrosion of the hull.
An anticorrosion voltage is applied between them, and an electric field 21 is generated in seawater.

This electric field 21 causes the movement of chlorine ions, and an interelectrode voltage (Vin) 301 is generated between the chlorine ion solid film electrodes 31 and 32 due to the difference in the amount of chlorine ions.

The inter-electrode voltage (Vin) 301 is amplified by the differential amplifier 4 and output as a reception signal 401.

The electric field sensor 7 is laid on the bottom of the sea, and the switch 6 is closed by the time delay circuit 5 because the time when the electrodes have become compatible with seawater has already passed, and the received signal 40
1 is output to the detector 8.

When the received signal 401 is larger than the threshold value (REF) 82, the detection signal 81 is generated and the passing ship 2
Can be detected. The threshold value (REF) 82 is set including a margin so as to be higher than the ambient noise level, for example, in consideration of preventing malfunction.

Next, the characteristics of the electric field sensor 7 using the chlorine ion solid film electrode described above will be described with reference to FIG. FIG. 3 is a diagram showing a difference in sensitivity between a chloride ion solid film electrode and a silver chloride electrode according to the electric field sensor of the present invention under a constant electric field. In FIG. 3, the solid line indicates the inter-electrode distance (cm) and inter-electrode voltage (mV) due to the chloride ion solid membrane electrode.
And the broken line shows the relationship between the inter-electrode distance (cm) and the inter-electrode voltage (mv) due to the silver chloride electrode.
The inter-electrode distance (cm) was expanded under a constant electric field and the inter-electrode voltage (mV) generated between the electrodes was measured. However, when the inter-electrode distance is the same, the chloride ion solid membrane electrode produces the electrode It can be seen that the inter-voltage is several times higher. That is, it can be seen that the chloride ion solid film electrode has higher detection sensitivity. Since the inter-electrode voltage increases as the inter-electrode distance increases, the electric field sensor of the present invention can increase or decrease the detection sensitivity by adjusting (changing) the inter-electrode distance.

In the conventional electric field sensor, a silver chloride electrode such as a reference electrode used for measurement of electrocorrosion has been adopted as an electrode. The silver chloride electrode, when an electric current flows in seawater,
This is a method for detecting the potential difference generated in the conductor resistance of seawater existing between the electrodes, but the chloride ion solid film electrode method is advantageous over the silver chloride electrode method in that the detection sensitivity is higher.

(Second Embodiment) Next, a second embodiment will be described with reference to FIG. Electric corrosion protection device 1
Even in a ship 2 that is not equipped with an AC electric field, an AC electric field corresponding to the electric field 21 is generated from the motor or generator, which is a power source, through the hull or ground depending on the rotation speed and the power supply frequency.

Such an AC electric field can also be detected by adding a bandpass filter and a detection circuit to the differential amplifier 4 of the block diagram of FIG. 1, and the operation will be described below.

An AC electric field signal is also applied to the electric field 2 of the cathodic protection device 1.
As in the case of No. 1, the chlorine ion solid film electrodes 31 and 32 detect the AC voltage Vin. The AC voltage Vin is amplified by the differential amplifier 4 and input to the bandpass filter. The center frequency of the bandpass filter is set to the rotation speed of the motor and the power supply frequency of the alternator, and the received signal 4 with the noise component removed by passing through this bandpass filter 4
It becomes 01. The reception signal 401 is detected by the detection circuit and output to the detector 8 as a DC signal, and the threshold value (REF) 82
When the detected value exceeds the threshold value (REF) 82, the detection signal 81 is output and the ship 2 is detected.

The present invention is not limited to the embodiments described above and shown in the drawings, but can be appropriately modified and implemented within the scope of the invention. For example, in the present embodiment, the ship 2 that travels over the sea has been described, but any object that radiates the electric field 21 (such as a underwater vehicle) can be detected by the electric field sensor 7 of the present invention. .

[0040]

The present invention is characterized by using a chloride ion solid membrane electrode as an electrode and having a time delay circuit until the electrode is adapted to seawater, and has the following effects.

The first effect is that the detection sensitivity is improved. The reason for this is that in conventional electric field sensors, a silver chloride electrode such as a reference electrode used for measurement of electrical corrosion protection has been adopted as an electrode. Is because the detection sensitivity is high.

The second effect is that the pressure resistance is high and the handling is easy. The reason is that the conventional electrode has a cylindrical structure that uses an internal liquid, and it is necessary to balance the pressure between seawater and the internal liquid by adding a compensator to secure the water pressure resistance. This is because the electrodes do not have these internal liquids and only solid electrodes do not require special consideration of water pressure resistance and maintenance of the internal liquids is not required. Further, the conventional electrode has an external structure that protrudes from the electric field sensor can body and is difficult to handle during laying work, etc., but the chloride ion solid film electrode used in the electric field sensor of the present invention is It can be installed without protruding.

[Brief description of drawings]

FIG. 1 is a block diagram showing a first embodiment of a chloride ion solid film electrode according to an electric field sensor of the present invention.

FIG. 2 is a chloride ion solid film according to the electric field sensor of the present invention.

FIG. 3 is a diagram showing a difference in sensitivity between a chloride ion solid film electrode and a silver chloride electrode according to the electric field sensor of the present invention under a constant electric field.

FIG. 4 is a standard electrode structure.

[Explanation of symbols]

1 Electrocorrosion protection device 11 Anode 12 cathode 2 ships 21 electric field 31, 32 Chloride ion solid membrane electrode 301 Electrode voltage (Vin) 302 resin stand 3001, 3002 Conductive wire 4 differential amplifier 5 time delay circuit 51, 52 contacts 53 contact signal 6 switch 7 Electric field sensor 71 Electric field sensor can 8 detectors 81 Detection signal 82 Threshold (REF) 91 Conductive wire 92 Support tube 93 reference electrode 94 Internal liquid 95 Ion-sensitive membrane 96 Internal liquid of diaphragm type electrode 97 Porous plate

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazuhisa Kobayashi             1-10 Nisshin-cho, Fuchu-shi, Tokyo             -Sea Network Sensor Co., Ltd.

Claims (10)

[Claims] 1. A solid-state electrode for generating a voltage in contact with seawater, a differential amplifier for amplifying an inter-electrode voltage generated between the solid-state electrodes, and a drift voltage generated for the solid-state electrode. An electric field sensor, comprising: a time delay circuit in which a convergence time from occurrence to disappearance is set. 2. A plurality of chlorine ion solid-state membrane electrodes that generate a voltage by touching seawater, a differential amplifier that amplifies an inter-electrode voltage generated between the plurality of chlorine ion solid-state membrane electrodes, and a plurality of the plurality of electrodes. An electric field sensor, comprising: a time delay circuit in which a convergence time from when a drift voltage generated between individual chlorine ion solid film electrodes is generated to when the drift voltage is eliminated is set. 3. The time delay circuit counts time when seawater is detected, and outputs a contact signal for outputting the signal output from the differential amplifier to the outside after the convergence time has elapsed. The electric field sensor according to claim 1 or 2. 4. The electric field sensor according to claim 1, wherein the time delay circuit includes two contacts that are short-circuited by seawater. 5. A contact that activates a timer when the time delay circuit detects seawater, and outputs the signal output from the differential amplifier to the outside after the convergence time preset in the timer has elapsed. The electric field sensor according to claim 1 or 2, which transmits a signal. 6. The value of the signal output from the differential amplifier is
The electric field sensor according to claim 1, wherein an electric field detection signal is output when the electric field detection signal is larger than a preset threshold value. 7. A plurality of chlorine ion solid membrane electrodes arranged at a fixed distance in a can of an electric field sensor, and an interelectrode voltage generated between the plurality of chlorine ion solid membrane electrodes is amplified. When the differential amplifier that outputs as a reception signal and the two contacts exposed to seawater are short-circuited by seawater, the time is counted, and after the preset convergence time of the drift voltage elapses, the differential amplifier outputs. A time delay circuit that outputs a contact signal that outputs the received signal to the outside, and receives the contact signal that the time delayed circuit outputs and outputs the received signal output from the differential amplifier to the outside An electric field sensor comprising: a switch that operates as described above; and a detector that outputs an electric field detection signal when the received signal sent by the switch becomes equal to or higher than a predetermined threshold value. 8. The differential amplifier further comprises a bandpass filter having a center frequency set to a power source frequency of a ship motor or generator, and a detection circuit for detecting an output from the bandpass filter. The electric field sensor according to claim 2, wherein the electric field sensor comprises: 9. The plurality of chloride ion solid membrane electrodes,
8. The electric field sensor according to claim 2, wherein the electric fields have the same area. 10. The electric field sensor according to claim 2, wherein the distance between the plurality of chloride ion solid film electrodes is variable.