JP4555927B2 - Electrochemical sensor and method of using the same - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to an electrochemical sensor, and more particularly to an electrochemical sensor that can always measure with a clean electrode even when it is set in a liquid to be examined.
[0002]
[Prior art]
For electrochemical measurements such as potentiometry and voltammetry in lakes, oceans, bioreactors or water treatment devices, etc., conductive materials that are chemically stable in water such as precious metals (platinum, gold, etc.) or carbon as electrodes Is often used.
However, it cannot be avoided that microorganisms or the like adhere to the electrode surface with the passage of time and the electrochemical characteristics of the electrode change to hinder accurate measurement.
[0003]
Therefore, in order to continue accurate measurement, it has been common to mechanically or chemically clean the electrodes.
However, mechanical or chemical cleaning itself affects the properties of the liquid to be inspected, and accurate measurement is often difficult.
In order to solve this problem, a wire electrode is used as a working electrode, and the wire electrode is sequentially moved so that the electrode is always kept clean.
[0004]
[Problems to be solved by the invention]
However, it is difficult not only to attach the wire electrode to the electrochemical sensor but also to prevent the liquid to be detected from leaking into the electrochemical sensor from the hole drilled in the electrochemical sensor in order to feed and pull the wire electrode. Met.
The present invention has been made in view of the above problems, and it is an object of the present invention to provide an electrochemical sensor that not only simplifies the mounting of wire electrodes but also can reliably prevent leakage of a liquid to be inspected inside. And
[0005]
[Means for Solving the Problems]
An electrochemical sensor according to a first aspect of the present invention is a hollow hermetically sealed casing, and is drawn along the outer surface of the hermetically sealed casing in the measuring section after being pulled out from the inside of the hermetically sealed casing in the measuring section of the sealed casing. A wire electrode made of a conductive material that can be drawn into the sealed housing from the outside through the lead-in hole, a wire electrode moving means that moves the wire electrode that is installed in the sealed housing and runs through the measuring unit, and a wire electrode. A counter electrode as an electrode; and a pressurized gas supply means for supplying a pressurized gas into the sealed casing.
[0009]
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 is a perspective view of an electrochemical sensor according to the present invention. A cylindrical casing covering the electrochemical sensor 1 is divided into an upper casing 11 and a lower casing 12.
A compressed gas supply connector 111 and an electric cable connector 112 are attached to the upper surface of the upper housing 11.
[0010]
A substrate 121 is disposed vertically on the lower housing 12, and a driving pulley 122 is disposed on the substrate 121. The drive pulley 122 is driven to rotate by a motor 123.
Direction change pulleys 124 and 125 are disposed under the substrate 121, and an attachment 13, a counter electrode 14, and a reference electrode 15 are disposed in the lower housing 12.
[0011]
The wire electrode 16 made of a conductive material that runs on the outer periphery of the attachment 13 extends downward from the drive pulley 122, is horizontally changed by the first direction changing pulley 124, and runs on the outer periphery of the attachment 13. The second direction change pulley 125 changes the direction vertically and extends upward to return to the drive pulley 122.
[0012]
Accordingly, when the drive pulley 122 is driven by the motor 123, the wire electrode 14 travels on the outer periphery of the attachment 13.
Note that a tension applying mechanism including, for example, three tension applying pulleys 1261, 1262, and 1263 may be installed on the substrate 121 to apply tension to the wire electrode 16 and prevent the wire electrode 16 from loosening.
[0013]
FIG. 2 is an enlarged view of the attachment attached to the lower housing, and the attachment 13 is housed in a recess 127 having a through-hole formed in the peripheral wall surface of the lower housing 12.
FIG. 3 is a three-side view of the attachment and a top view of the resin tube. The attachment 13 is divided into an upper attachment 131 and a lower attachment 132.
[0014]
Two parallel semicircular grooves are formed on the opposing surfaces of the upper attachment 131 and the lower attachment 132, and a U-shaped resin tube 17 through which the wire electrode 16 passes is inserted into the grooves. . Thereafter, the upper attachment 131 and the lower attachment 132 are assembled together by four coupling screws 133.
[0015]
The integrally assembled attachment 13 is housed in a recess 127 formed on the peripheral wall surface of the lower housing 12 and is fixed to the lower housing 12 by four mounting screws 134. The bottom surface of the recess 127 is provided with a through-hole penetrating into the lower housing 12 and a sealing material such as silicon rubber is attached.
An opening 171 is formed at the bottom of the U-shaped resin tube 17, and the wire electrode 16 is exposed from the opening 171. The wire electrode 16 is drawn into the inside of the lower housing 12 through a through hole in the bottom surface of the concave portion 127 of the lower housing 12, one through the tension applying pulleys 1261, 1262 and 1263, and the other directly driven pulley. It is led to 122 and tied on the drive pulley 122 to form a loop.
[0016]
In order to electrically connect the wire electrode 16 to one pole of the signal cable, a current collecting pillow 128 is installed on the inner bottom surface of the lower housing 12. The other pole of the signal cable is connected to the counter electrode 14.
The counter electrode 14 is an electrode that forms a pair with the wire electrode 16 that functions as a working electrode, and can be installed within an appropriate range from the wire electrode 16. In addition, when the attachment 13 or the lower housing 12 is made of a conductive material, the attachment 13 or the lower housing 12 can be used as the counter electrode 14.
[0017]
After the mounting of the wire electrode 16 is completed, the upper casing 11 is covered and the pressurized gas supply pipe 111 is connected to the pressurized gas supply connector 111, and the electric cable is connected to the electric cable connector 112. Sink the sensor.
As is clear from the enlarged view of FIG. 2, the reference electrode 15 is disposed immediately above the opening 127. The reference electrode 15 is L-shaped, and the long side is inserted into a mounting hole 151 penetrating the lower housing 12 and drawn into the lower housing 12. The short side extends downward outside the lower housing 12 and is close to the opening 171 of the resin tube 17. In addition, a nut 153 is screwed into the lower housing 12 with the O-ring 152 sandwiched in front of the attachment hole 151 to prevent the inspection target liquid from leaking from the attachment hole 151.
[0018]
The pressure of the pressurized gas supplied from the compressed gas supply pipe 111 is set such that the electrochemical sensor is set to prevent leakage of the liquid to be inspected from the gap between the wire electrode 16 and the U-shaped resin tube 17. Adjust the pressure to match the external pressure at the position.
That is, the lower housing 12 is provided with a gas escape hole 129 above the recess 127 for storing the attachment 13. The gas pressure in the gas escape hole 129 is changed to the static pressure of the liquid to be inspected at the position of the gas escape hole 129. The wire electrode 16 is adjusted by adjusting the pressure of the pressurized gas so that the pressurized gas escapes from the gas escape hole 129 at a constant rate by adjusting the pressure obtained by adding the water head pressure difference between the escape hole 129 and the resin tube 17. It is possible to prevent the meniscus position in the gap between the resin tube 17 from fluctuating.
[0019]
The electric cable transmits power flowing from the counter electrode 14 to the wire electrode 16 through the liquid to be measured to the indicating unit (not shown). 15 and a signal cable for measuring a potential generated between the first and second terminals. That is, the order of installation of the electrochemical sensor according to the present invention at the detection position is as follows.
1. The wire electrode 16 is inserted into the resin tube 17.
2. The resin tube 17 is bent into a U shape so that the opening of the resin tube 17 comes to the outer curved portion.
3. The resin tube 17 bent into a U-shape is fitted into the groove of the upper attachment 131 (or the lower attachment 132) so that the U-shaped bottom portion comes to the outside, and the lower attachment 132 (or the upper attachment 131) is combined with the attachment screw 133. Assemble together.
4). The assembled attachment 13 is fixed to the lower housing 12 with fixing screws 134.
5). The wire electrode 16 is guided to the driving pulley 122 through the direction changing pulleys 124 and 125, and both ends are connected to form a loop.
6). The upper casing 11 covers the lower casing 12 and seals the connecting portion.
7). A pressurized gas supply pipe is connected to the pressurized gas supply connector 111 of the upper housing 11, and an electric cable is connected to the electric cable connector 112.
8). Install the electrochemical sensor at the detection position.
9. The pressure of the pressurized gas is adjusted so that the liquid to be inspected does not leak inside the housing.
[0020]
The size of the electrochemical sensor according to the present invention is not particularly defined. For example, the upper housing can have an outer diameter of 180 mm × height of 250 mm, and the lower housing can have an outer diameter of 180 mm × height of 50 mm.
[0021]
【The invention's effect】
According to the electrochemical sensor of the first aspect of the invention, the working electrode can be kept clean by driving the wire electrode on the attachment attached to the outer periphery of the sealed casing by the wire electrode driving means stored in the sealed casing. It becomes possible to maintain the state.
[Brief description of the drawings]
FIG. 1 is a perspective view of an electrochemical sensor according to the present invention.
FIG. 2 is an enlarged view of an attachment attached to a lower housing.
FIG. 3 is a three-side view of the attachment.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... Electrochemical sensor 11 ... Upper housing | casing 12 ... Lower housing | casing 121 ... Board | substrate 122 ... Drive pulley 123 ... Motor 124, 125 ... Direction change pulley 128 ... Current collecting pillow 129 ... Escape hole 13 ... Attachment 14 ... Counter electrode 15 ... reference Electrode 16 ... Wire electrode

Claims (6)

A hollow sealed housing;
In the measurement unit of the sealed casing, the lead is pulled out from the inside of the sealed casing through the pull-out hole, travels along the outer surface of the sealed casing in the measurement unit, and from the outside of the sealed casing through the pull-in hole. A wire electrode made of a conductive material drawn into the interior;
Wire electrode moving means installed in the sealed casing and moving the wire electrode;
A counter electrode which is an electrode paired with the wire electrode;
An electrochemical sensor comprising pressurized gas supply means for supplying pressurized gas into the sealed casing. The electrochemical sensor according to claim 1, wherein the measurement unit includes an attachment that is removable from an outer surface of the sealed casing. The attachment is an upper attachment;
A lower attachment facing the upper attachment;
A U-shaped insulating tube sandwiched between the upper attachment and the lower attachment and having an opening through which the wire electrode penetrates and the wire electrode is exposed in an outer curved portion. 2. The electrochemical sensor according to 2. The electrochemical sensor according to any one of claims 2 to 3, wherein the attachment is made of a conductive material and functions as a counter electrode. The sealed enclosure
A lower housing in which the measurement unit, the wire electrode, and the wire electrode moving means are mounted;
The electrochemical sensor according to any one of claims 1 to 4, wherein the electrochemical sensor includes an upper casing that covers the lower casing. The lower housing is
The electrochemical sensor according to claim 5, further comprising an escape hole for allowing the pressurized gas supplied from the pressurized gas supply pipe to escape.

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