JP2006029860A - Electrode for current detection - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an electrode of small, light weight and low cost for current detection with a small contact resistance with the seawater. <P>SOLUTION: The main body of the electrode 11 is made of AgCl plated silver rod or a platinum rod, and the contact part with the seawater is made a pipe shape, the inside and outside of which are used as a contact area. Thereby, the contact area can be enlarged approximately twice that of the rod electrode 11 without enlarging the outer shape of the electrode 11 and the contact resistance between the electrode and the seawater is reduced to 1/2 and also the manufacturing cost can be reduced because of reduction of material cost for the noble metal. <P>COPYRIGHT: (C)2006,JPO&NCIPI

Description

The present invention relates to a current detection electrode for detecting a current flowing in an electrolyte solution, and more particularly to a current detection electrode for detecting a current flowing from a ship into seawater.

Usually, various metal materials are used for the landing part of a steel ship. For example, assuming that zinc Zn is used outside the ship and copper Cu is used in the screw part, the following reaction formula is shown on the Zn and Cu surfaces in seawater corresponding to an electrolyte solution containing about 3.5% NaCl. The redox reaction occurs.
Zn oxidation reaction: Zn → Zn ²⁺ + 2e
Reduction reaction of Cu: Cu ²⁺ + 2e → Cu

That is, electrons (e) are emitted by the oxidation reaction on the Zn surface, and electrons (e) are taken in on the Cu surface. And since the ship exterior and the screw part are connected by metal etc. and are electrically connected, electrons flow from the Zn side to the Cu side, current flows in the opposite direction, and the Cu side has a higher potential than the Zn side. As a result, current flows from the Cu surface to the Zn surface side in seawater. In this way, when different kinds of metals are present in seawater, currents of different sizes flow due to the difference in the metals.
In general, in a steel ship, ship corrosion protection is generally performed in which a large number of electrodes are provided outside the ship and current is supplied to these for cathodic protection.

  In recent years, there has been a demand for a system aimed at monitoring the entry of ships into harbors as a countermeasure against terrorism. In the present invention, in order to detect the current around the ship and detect the presence and movement state of the ship, a method is used in which electrodes 30 and 31 are installed in seawater and the current is detected as a voltage as shown in FIG. . Until now, the electrode for detecting the voltage in the sea is a rod as shown in FIG. 6, and AgCl plating or a platinum rod is used as the electrode body 32 on the silver rod. The voltage due to the current in the seawater is detected by this electrode and transmitted to a receiver (not shown) on the sea via a cable portion 34 sealed with an O-ring 33 or the like. For example, in the case of a moving ship, the current direction of the detection signal may be reversed depending on the moving direction of the ship with respect to the electrode, and the magnitude and polarity of the detection signal change with time as shown in FIG.

The detection signal is subjected to signal amplification processing by an electric circuit as shown in FIG. 8 to a level necessary for display and recording. In FIG. 8, I is a current flowing in seawater, R1 is seawater equivalent resistance inversely proportional to the conductivity of seawater, R2 and R3 are contact resistances between the electrodes 30, 31 and seawater, B1 and B2 are power supplies, and A1 is It is a differential amplifier.
Japanese Patent No. 2617229 Japanese Patent Application Laid-Open No. 08-12252

There is a noise current at the input of the differential amplifier A1. Since this noise current flows through the contact resistors R2 and R3, it becomes a noise voltage and is amplified together with the signal by the differential amplifier A1 and appears at the output. Therefore, it is preferable to reduce the contact resistances R2 and R3.
On the other hand, when the conventional rod-shaped electrode body 32 is used, in order to reduce the contact resistances R2 and R3, at least one of the length and the diameter of the electrode body 32 must be increased, which increases the weight. There was a problem that the material cost as a noble metal became high.

  The present invention has been made in view of such circumstances, and by making the contact portion of the electrode main body with seawater into a pipe shape, a spiral shape, or a roll shape, the contact resistance is small, lightweight, and low in cost. An object of the present invention is to provide a current detection electrode having a stable signal amplification degree.

In order to achieve the above object, a current detection electrode according to the invention of claim 1 is provided between any two points in an electrolyte solution, and includes a current provided with an electrode main body that detects a current flowing between them as a minute voltage. In the detection electrode, the shape of the contact portion of the electrode body with the electrolyte solution is a pipe.
The current detection electrode according to the invention of claim 2 is provided between any two points in the electrolyte solution, and the current detection electrode includes an electrode main body that detects a current flowing between them as a minute voltage. The shape of the contact portion with the electrolyte solution is a spiral shape or a roll shape.
The current detection electrode of the present invention is configured as described above, and the contact resistance between seawater and the electrode is small, so that a low-cost electrode can be obtained.

  The current detection electrode of the present invention is configured as described above. By changing the shape of the electrode body from a rod to a pipe, spiral, or roll, the contact area with seawater increases and the contact resistance decreases. Stable measurement accuracy can be obtained. In addition, the electrode body requires less noble metal material, is small and light, and can reduce material costs.

  Hereinafter, embodiments of the current detection electrode of the present invention will be described with reference to the drawings. FIG. 1 is a structural diagram of an embodiment of a current detection electrode according to the present invention. In this electrode, a silver-plated AgCl-plated bar or a platinum bar processed into a pipe shape is attached to a resin-made block 17 such as plastic in which O-rings 14, 15, 16 for sealing intrusion of seawater are fitted. The electrode assembly 1 inserted and fixed by the electrode fixing bracket 18, the outer tube 2 for electrode protection screwed by the screw portion of the electrode assembly 1, and the cable portion 3 for transmitting the detection signal of the electrode body 11 It is composed of

FIG. 2 shows a structural diagram of the electrode assembly 1. The electrode body 11 is secured to the block 17 with a retaining member 11a fixed to the circumference of the electrode body 11 by welding or the like. The retaining member 11a and the electrode fixing bracket 18 shown in FIG.
The cable part 3 is attached by soldering the lead wire 3a in the cable to the terminal 20 in advance and connecting the terminal 20 to the electrode body 11 with the terminal fixing screw 19 and then screwing it to the electrode assembly part 1. It is done. The electrode body 11 is prevented from adhering floating substances in seawater by the outer cylinder 2 and the filter 21.

  Seawater can contact the inner and outer surfaces of the pipe portion of the electrode body 11 protruding from the block 17, and the contact area is about twice that of the electrode body 32 (FIG. 6) when it is made of a rod. It becomes. Therefore, the contact resistance between the electrode body 11 and seawater, that is, the contact resistances R2 and R3 in FIG. 8, is reduced to about ½ when the rod-shaped electrode body 32 is used.

  FIG. 3 is a plan view (a) and a side view (b) of an electrode body 12 for carrying out the invention of claim 2. As shown in FIG. 3, the main electrode body 12 is formed by integrating a metal plate with a metal rod and welding, etc., in which a plate material having a constant width of silver (AgCl on the surface) or platinum is spirally wound. is there. Since contact with seawater is performed on the inner and outer surfaces of the cylinder, a contact area approximately twice that of the conventional electrode can be secured in the same manner as the electrode body 11 of FIG. 2, and the contact resistances R2 and R3 are reduced accordingly. can do.

FIG. 4 is a plan view (a) and a side view (b) of another electrode body 13 for carrying out the invention of claim 2. As shown in FIG. 4, the main electrode body 13 is formed by integrating a silver or platinum plate material in a roll shape while maintaining a certain interval, and integrating it with a metal rod and welding. Since contact with seawater is performed on the inner and outer surfaces of the cylindrical body, the contact area can be further increased as compared with the electrode body 11 of FIG. 2 and the electrode body 32 of FIG. 6, and accordingly, the contact resistances R2 and R3 are reduced. be able to.
Since the electrode bodies 11, 12, and 13 can save the noble metal material corresponding to the hollow portion, the material cost is reduced accordingly.

  The present invention is used for detecting a current flowing through an electrolyte solution, particularly a current detecting electrode for detecting a current flowing into seawater from a ship.

FIG. 3 is a structural diagram showing an example of a current detection electrode according to the present invention. It is a structural diagram of the electrode body of the present invention. FIG. 3 is a structural diagram of an electrode body for carrying out the invention of claim 2. It is a structural view of another electrode for carrying out the invention of claim 2. It is explanatory drawing which shows a ship detection method. FIG. 3 is a structural diagram of an electrode that is normally used to detect a voltage in the sea. It is a change figure of a detection signal accompanying ship movement. It is an electric circuit diagram which amplifies a detection signal.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Electrode assembly part 2 Outer cylinder 3 Cable part 3a Lead wire 11, 12, 13, 32 Electrode main body 11a Detachment 14, 15, 16, 33 O-ring 17 Block 18 Electrode fixing bracket 19 Terminal fixing screw 20 Terminal 21 Filter 30 31 Electrode 34 Cable part A1 Differential amplifier B1, B2 Power supply I Current R1 Seawater equivalent resistance R2, R3 Contact resistance

Claims (2)

  In a current detection electrode provided with an electrode body that is installed between any two points in the electrolyte solution and detects a current flowing between them as a minute voltage, the shape of the contact portion of the electrode body with the electrolyte solution is made into a pipe shape. An electrode for current detection.   In a current detection electrode provided between two arbitrary points in the electrolyte solution and detecting the current flowing between them as a minute voltage, the shape of the contact portion of the electrode body with the electrolyte solution is spiral or roll An electrode for current detection characterized by having a shape.

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