JP2018017581A - Ozone water concentration sensor and ozone water concentration measurement device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an ozone water concentration sensor and an ozone water concentration measurement device which can measure the concentration of a small amount of ozone water more sufficiently and more precisely by any one of a batch measurement method and a continuous measurement method.SOLUTION: An ozone water concentration sensor 10 includes a detection electrode 1 and a comparison electrode 2 made of metals with different ionization tendencies, the detection electrode 1 surrounding the comparison electrode 2. The ozone water concentration measurement device has the ozone water concentration sensor.SELECTED DRAWING: Figure 1A

Description

  The present invention relates to an ozone water concentration sensor and an ozone water concentration measuring device for measuring ozone concentration in water in which ozone is dissolved.

  Ozone water has been recognized to contribute to many fields, such as its bactericidal and deodorizing properties and its activity on cells. Furthermore, ozone dissolved in water has no effect on the respiratory tract, so ozone water is widely used in industrial, medical and nursing fields. However, since the concentration of ozone water attenuates in a short time, there is a strong demand for indication and confirmation of the concentration at the site of use.

  Conventionally, as a method for calibrating the concentration of ozone water, a titration method that observes the color change of a test agent such as potassium iodide has been a regular measurement method. Such a calibration method requires chemicals and a precision pipette and can be used in a laboratory or the like, but it is complicated and impractical at a general ozone water use site. A coulometric method that mechanizes the calibration method has been put into practical use, and a measurement method that digitally displays a concentration measurement value has been proposed. Such a measurement method is also a batch measurement method that requires a reagent such as potassium iodide solution. Other color-changing reagent methods using dyes such as indigo have also been proposed, but they are also batch measurement methods that require reagents, and it takes time to measure the ozone concentration. It is still unfit for. In addition, a method of measuring degassed ozone by bubbling air in ozone water has been proposed, but a detection measurement tube is required as a consumable. Both methods are batch measurement methods and cannot be used for continuous measurement.

  Therefore, an ultraviolet absorption method for examining the ultraviolet absorption rate of ozone water and an electrode system using a pair of electrodes having different ionization tendencies are used.

  The ultraviolet absorption method is capable of continuous measurement and is used as the most reliable concentration meter, but is extremely expensive.

  There are two types of electrode methods: a diaphragm type using an ozone permeable membrane and a bare electrode type measuring directly by immersing the electrode in ozone water without using a diaphragm. However, both require an electrolyte and do not allow continuous measurement. It was possible. In particular, since the bare electrode method can measure ozone concentration in a short time, for example, Patent Document 1 and Patent Document 2 show measuring devices. However, as described above, an electrolyte is required and continuous measurement cannot be performed. In particular, the measuring device of Patent Document 2 needs to be shaken by a person even in the measurement operation, and the measurement result is affected by the shaking speed.

  Further, Patent Document 3 discloses that even if ozone water is dissolved in purified water or pure water having extremely low electrical conductivity, a sensor between the detection electrode and the comparison electrode is used as a sensor for accurately measuring the concentration of ozone water. A “bare electrode type” ozone water concentration sensor having a three-layer structure sandwiching a mesh-like or cloth-like insulator has been proposed. In the “bare electrode type” ozone water concentration sensor 200 having a three-layer structure, as shown in FIG. 9, the detection electrode 201 is disposed inside the comparison electrode 202. Specifically, the ozone water concentration sensor 200 has a structure in which the comparison electrode 202 covers the outside of the detection electrode 201 with an insulator 203 interposed between the comparison electrode 202 and the detection electrode 201, and the comparison electrode 202 is an end portion of the detection electrode 201. And has a structure having a U-shaped cross section.

JP-A-8-304334 JP 2005-134135 A JP 2012-1227889 A

The inventors of the present invention have found the following problems in the ozone water concentration sensor 200:
(1) Since the detection electrode is covered with the comparison electrode, the supply of ozone water to the detection electrode is limited, and a particularly sufficient output cannot be obtained when the amount of ozone water is small.
(2) If the supply of ozone water to the detection electrode is restricted, the continuous supply of ozone water on the detection electrode surface is insufficient, so the concentration of ozone water decreases, so-called polarization occurs, and the sensor output decreases. To do.
(3) If the sensor output decreases, the reproducibility deteriorates or the measured values vary, and the ozone concentration cannot be measured accurately.

  The present invention provides a bare electrode type ozone water concentration sensor capable of measuring ozone water concentration more accurately even with a small amount of ozone water, without the need for an electrolyte, a reagent, etc., and capable of using a batch measurement method or a continuous measurement method. An object is to provide an ozone water concentration measuring apparatus using the same.

The present invention
Comprising a detection electrode and a reference electrode made of metals having different ionization tendencies,
The reference electrode is disposed inside the detection electrode;
The present invention relates to an ozone water concentration sensor in which the detection electrode is arranged so as to surround the comparison electrode.

  The present invention also relates to an ozone water concentration measuring device having the ozone water concentration sensor.

  According to the ozone water concentration sensor and the ozone water concentration measuring device of the present invention, the ozone water concentration can be measured with higher accuracy even when the amount of ozone water is small. Furthermore, the ozone water concentration can be measured more accurately even when the water temperature is low or the ozone water concentration is low such that the sensor output decreases due to a decrease in the reaction rate at the electrode.

  The ozone water concentration sensor of the present invention belongs to the bare electrode type, and can measure the ozone concentration by a batch measurement method and a continuous measurement method without using an electrolyte solution and a reagent.

1 is a schematic perspective view of an ozone water concentration sensor according to a first embodiment of the present invention. It is the schematic side view and partial enlarged view of the ozone water concentration sensor which concern on 1st embodiment of this invention. It is a schematic sectional drawing which shows the use condition of the ozone water concentration sensor which concerns on the 1st embodiment of this invention. It is a schematic perspective view of the ozone water concentration sensor which concerns on the 2nd embodiment of this invention. It is a schematic side view of the ozone water concentration sensor which concerns on the 2nd embodiment of this invention. It is a schematic front view of the ozone water concentration sensor which concerns on the 2nd embodiment of this invention. It is a schematic sectional drawing which shows the use condition of the ozone water concentration sensor which concerns on the 2nd embodiment of this invention. It is a schematic sectional drawing of the ozone water concentration measuring apparatus which concerns on the 1st embodiment of this invention. It is a schematic sectional drawing of the ozone water concentration measuring apparatus which concerns on the 2nd embodiment of this invention. It is a schematic sectional drawing of the ozone water concentration measuring apparatus which concerns on the 3rd embodiment of this invention. It is a graph which shows the relationship between the sensor output measured in the Example, and water temperature. It is a graph which shows the relationship between the sensor output and ozone water concentration which were measured in the Example. It is a graph which shows the relationship between the sensor output, ozone water density | concentration, and ozone water amount which were measured in the Example. It is a schematic perspective view of the ozone water concentration sensor in a prior art.

[Ozone water concentration sensor]
The ozone water concentration sensor of the present invention is a sensor that detects the ozone concentration of ozone water flowing in a water passage or a water tank. The ozone water concentration sensor of the present invention includes a pair of electrodes composed of metals having different ionization tendencies, that is, a detection electrode and a comparison electrode.

  In the ozone water concentration sensor of the present invention, as shown in FIGS. 1A and 2A, the detection electrodes 1 and 11 are arranged so as to surround the comparison electrodes 2 and 12. That the detection electrode is disposed so as to surround the comparison electrode means that the detection electrode is disposed relatively outside and the comparison electrode is disposed relatively inside. In the present invention, the detection electrode is disposed. The detection electrode may be arranged so as to surround or cover the comparison electrode while maintaining a non-contact state with the comparison electrode. For example, when the comparison electrode has a flat plate shape as shown in FIG. 1A, the detection electrode 1 covers at least one of the two relatively large surfaces of the comparison electrode 2, preferably both surfaces. It only has to be arranged. Further, for example, when the comparison electrode has a linear shape as shown in FIG. 2A, the detection electrode 11 only needs to be disposed so as to surround at least a part of the linear shape. Specifically, the comparison electrodes 2 and 12 are arranged inside the detection electrodes 1 and 11, and the detection electrodes 1 and 11 are arranged so as to surround or cover the outside of the comparison electrodes 2 and 12 inside thereof. When the sensor of the present invention has such an electrode structure, ozone water having a concentration to be measured can be continuously supplied to the surface of the detection electrode, and the reduction reaction of ozone water on the electrode surface can be continuously and efficiently performed. As a result, an increase in sensor output can be achieved, so that the ozone concentration can be measured with sufficient accuracy. 1A and 2A are schematic perspective views of an ozone water concentration sensor according to a first embodiment and a second embodiment of the present invention, respectively.

  The electrode structure of the ozone water concentration sensor is not particularly limited as long as the detection electrode is arranged so as to surround the comparison electrode. For example, the ozone water concentration sensor may have the following structure:

First embodiment;
As shown in FIG. 1A, a structure in which the detection electrode 1 covers the outside of the comparison electrode 2 with an insulator 3 sandwiched between the detection electrode 1; and a second embodiment;
As shown in FIG. 2A, a structure in which the comparison electrode 12 is arranged inside the detection electrode 11 and spaced from the detection electrode 11.

  A preferable electrode structure from the viewpoint of further increasing the sensor output is the structure according to the first embodiment.

  Hereinafter, the ozone water concentration sensor according to the present invention will be described in detail with reference to the drawings according to some embodiments, but various elements in the drawings are merely schematically and exemplarily shown for understanding of the present invention. First, the appearance and dimensional ratio may differ from the actual product. The “vertical direction”, “left / right direction”, and “front / back direction” used directly or indirectly in this specification correspond to directions corresponding to the vertical direction, left / right direction, and front / back direction in the drawing, respectively. Unless otherwise specified, the same symbols or symbols indicate the same members or the same meaning.

(First embodiment)
In the ozone water concentration sensor 10 according to the first embodiment, as shown in FIG. 1A, the detection electrode 1 is disposed so as to surround the comparison electrode 2. Specifically, the comparison electrode 2 is arranged inside the detection electrode 1, and the detection electrode 1 is arranged so as to cover the outside of the comparison electrode 2 inside. FIG. 1A is a schematic perspective view of an ozone water concentration sensor according to a first embodiment of the present invention.

  In the ozone water concentration sensor 10, as shown in FIG. 1A, the detection electrode 1 is provided so as to cover both surfaces of the comparison electrode 2. The comparison electrode 2 is arranged inside the folded detection electrode 1, that is, the detection electrode 1 is folded at the end of the comparison electrode 2 to have a U shape. This embodiment is not limited to such a folding structure of the detection electrode, and does not prevent the detection electrodes 1 from being discontinuously arranged separately on both sides of the comparison electrode 2.

  The ozone water concentration sensor 10 further includes an insulator 3 having water permeability for preventing contact between the detection electrode 1 and the comparison electrode 2. The insulator 3 keeps a space between the detection electrode 1 and the comparison electrode 2 at a narrow and uniform interval to ensure a non-contact state between the detection electrode 1 and the comparison electrode 2. The ozone water concentration sensor 10 has a structure in which the detection electrode 1 covers the outside of the comparison electrode 2 with an insulator 3 interposed between the detection electrode 1 and the comparison electrode 2.

  The detection electrode 1 has a flat plate shape, and as shown in FIG. 1B, the surface area of the electrode can be increased. Therefore, the detection electrode 1 has a multilayer structure in which a plurality of metal micromesh is laminated. This does not prevent the detection electrode from being composed of a single metal micromesh and the use of a metal sheet without a mesh instead of the metal micromesh. In FIG. 1B, the detection electrode 1 has three stacked micro meshes, but it is preferable to stack two to five metal micro meshes in order to obtain sufficient output. FIG. 1B is a schematic side view and a partially enlarged view of the ozone water concentration sensor according to the first embodiment of the present invention. In the present specification, the metal micromesh is a wire mesh having a mesh structure having a maximum mesh size of about 1 mm or less, for example, 100 μm to 1 mm.

  The metal constituting the detection electrode 1 is a metal having a smaller ionization tendency than the metal constituting the comparison electrode 2. For example, the detection electrode 1 is composed of at least a surface of gold or a gold plating layer or platinum or a platinum plating layer. The The detection electrode 1 may be a so-called conductive diamond electrode.

  The thickness of one metal micromesh constituting the detection electrode 1 is preferably 0.05 mm to 0.2 mm. When a plurality of metal micromesh are used in a stacked manner, the thickness of the detection electrode 1 is 0. .3 mm to 1 mm is preferable.

  Since the reference electrode 2 has a flat plate shape and can take a large surface area of the electrode, it has a multi-layer structure in which a plurality of metal micromesh is laminated. It does not preclude the use of a metal sheet having no mesh instead of a metal micromesh made of metal. In FIG. 1B, the reference electrode 2 is formed by stacking four metal micromesh, but it is preferable to stack three or five metal micromesh to obtain sufficient output.

  The metal constituting the comparison electrode 2 is a metal having a higher ionization tendency than the metal constituting the detection electrode, and is, for example, silver. The comparison electrode 2 may have at least a surface made of silver, silver chloride, or silver oxide. That is, the reference electrode 2 may be silver, or may be one in which the surface of silver is protected with a conductive film. Examples of the conductive coating include silver chloride, silver oxide, and a naphthion membrane (cation exchange membrane).

  The thickness of one metal micromesh constituting the comparison electrode 2 is preferably 0.05 mm to 0.5 mm. When a plurality of metal micromesh are used in an overlapping manner, the thickness of the comparison electrode 2 is 0. .3 mm to 2 mm is preferable.

  The dimensions of the ozone water concentration sensor 10 are not particularly limited as long as the ozone water concentration can be measured. For example, the width w1 (see FIG. 1A) is usually 5 to 20 mm, and preferably 5 to 10 mm. For example, the height h1 (see FIG. 1A) is usually 5 to 20 mm, and preferably 5 to 10 mm from the viewpoint of further increasing the sensor output.

  The insulator 3 has a micromesh shape or a cloth shape, and is in contact with the inner surface of the detection electrode 1 and is in contact with the outer surface of the comparison electrode 2 and is sandwiched between the detection electrode 1 and the comparison electrode 2. The micro-mesh form is a form having a mesh structure having a maximum mesh size of about 1 mm or less, for example, 100 μm to 1 mm.

  As a material constituting the insulator 3, for example, Teflon (registered trademark), tetrafluoroethylene / perfluoroalkyl vinyl ether copolymer (PFA), polyester, polypropylene, polyethylene or the like can be used. In particular, Teflon and PFA are preferable in terms of ozone resistance.

  The thickness of the insulator 3 is usually 1 mm or less, particularly 0.05 to 1 mm, preferably 0.05 to 0.5 mm, more preferably, from the viewpoint of availability of the insulator 3 and further increase in sensor output. Is 0.05 to 0.3 mm. By using this insulator 3, the interval between the detection electrode 1 and the comparison electrode 2 in the ozone water concentration sensor can be controlled. The interval (distance) between the detection electrode 1 and the comparison electrode 2 in the ozone water concentration sensor 10 is usually 1 mm or less, preferably 0.5 mm or less. The lower limit value of the interval is not particularly limited as long as non-contact between the detection electrode 1 and the comparison electrode 2 is ensured, and the interval is usually 0.01 mm or more, preferably 0.05 mm or more.

A part of the lower end of the detection electrode 1 extends downward, a lead wire 4 is connected to the extension 1a, and the lead wire 4 is connected to a positive electrode of an ammeter (not shown). As the ammeter, a micro-ampere ammeter can be used.
A part of the lower end portion of the comparison electrode 2 extends downward, a lead wire 5 is connected to the extension portion 2a, and the lead wire 5 is connected to the negative electrode of the ammeter.

  The extension part 1 a of the detection electrode 1 and the extension part 2 a of the comparison electrode 2 are embedded in the base 6 and penetrate the lower surface of the base 6. That is, the detection electrode 1, the comparison electrode 2, and the insulator 3 protrude from the upper surface of the base 6.

  A seal member 7 is provided on a part of the outer peripheral surface of the base 6 along the outer peripheral surface. Examples of the seal member 7 include an O-ring, rubber packing, a lip seal, and a sealant. For example, as shown in FIG. 1C, the seal member 7 has a through hole 101 formed in a wall surface 100 that forms a water passage serving as a passage for ozone water, and the base 6 is fitted into the through hole 101 to thereby adjust the ozone water concentration. This is to ensure water tightness between the through hole 101 and the base 6 when the sensor 10 is attached. FIG. 1C is a schematic cross-sectional view showing a usage state of the ozone water concentration sensor according to the first embodiment of the present invention.

  The ozone water concentration sensor 10 having the above configuration is immersed in, for example, ozone water flowing in a water passage or ozone water in a water tank to bring the detection electrode 1 and the comparison electrode 2 into contact with the ozone water. As a result, an electromotive force is generated, and a stable electric signal having a strength proportional to the ozone water concentration is obtained, and the concentration of ozone water is measured.

  The relationship between the installation direction of the ozone water concentration sensor 10 and the flow direction of the ozone water is not particularly limited. When the ozone water concentration sensor 10 is arranged in the direction shown in FIG. 1A, the flow direction of the ozone water is D1 to D4. Either direction may be used. In FIG. 1A, for example, when the flow direction of ozone water is D1 or D3, the detection electrode 1 is in a substantially vertical relationship with the flow direction of ozone water. For example, when the flow direction of the ozone water is D2 or D4, the detection electrode 1 is in a substantially parallel relationship with the flow direction of the ozone water.

  From the viewpoint of further increasing the sensor output, the ozone water concentration sensor 10 is preferably installed so that the detection electrode is not obstructed from contacting the ozone water by the comparison electrode. The detection electrode is not obstructed by the comparison electrode in contact with the flow of ozone water. In the flow direction of the ozone water, is the most upstream part of the detection electrode disposed at the same position as the most upstream part of the comparison electrode (for example, , D2 or D4 in FIG. 1A), or the most upstream part of the detection electrode is arranged at a position upstream of the most upstream part of the comparison electrode (for example, D1 or D3 in FIG. 1A). When the ozone water concentration sensor 10 is installed in the direction shown in FIG. 1A, the flow direction of the ozone water is preferably D2 or D4. FIG. 1C is a schematic cross-sectional view showing the usage state of the ozone water concentration sensor when the flow direction of the ozone water is D2 in FIG. 1A.

  As described above, according to this embodiment, the detection electrode 1 is provided so as to surround the comparison electrode 2, and the insulator 3 is provided between the two electrodes. For this reason, ozone water can contact the detection electrode continuously and effectively without being obstructed by the comparison electrode, and the reduction reaction at the ozone detection electrode can be continuously and efficiently caused. In addition, by reducing the thickness of the insulator 3, the distance between the two electrodes can be easily reduced. As a result, the sensor output can be significantly increased. For this reason, the bare electrode type ozone water concentration sensor 10 with very high sensor performance can be obtained. Therefore, it is possible to efficiently measure the ozone water concentration even for a small amount of ozone water.

(Second embodiment)
The ozone water concentration sensor according to the second embodiment is similar to the ozone water concentration sensor according to the first embodiment in that the detection electrode is disposed so as to surround the comparison electrode. The shape is different. The ozone water concentration sensor according to the second embodiment is the same as the ozone water concentration sensor according to the first embodiment, except as described below.

  In the ozone water concentration sensor 20 according to the second embodiment, as shown in FIG. 2A, the detection electrode 11 is disposed so as to surround the comparison electrode 12. Specifically, the comparison electrode 12 is arranged inside the detection electrode 11, and the detection electrode 11 is arranged so as to surround or cover the comparison electrode 12 inside. FIG. 2A is a schematic perspective view of an ozone water concentration sensor according to a second embodiment of the present invention.

  In the ozone water concentration sensor 20, as shown in FIG. 2A, the comparison electrode 12 is arranged inside the detection electrode 11 so as to be separated from the detection electrode 11, and the detection electrode 11 and the comparison electrode 12 are not in contact with each other. It is secured. 2A to 2C, the detection electrode 11 has a cylindrical shape, but is not particularly limited as long as it has a cylindrical shape, and may be a polygonal cylindrical shape such as a square cylindrical shape. The comparison electrode 12 has a coil shape (spiral shape), but is not particularly limited as long as it has a linear shape, and may be, for example, a linear shape. From the viewpoint of further increasing the sensor output, it is preferable that the detection electrode 11 has a cylindrical shape and the comparison electrode 12 has a coil shape. FIG. 2B is a schematic side view of an ozone water concentration sensor according to the second embodiment of the present invention. FIG. 2C is a schematic front view of an ozone water concentration sensor according to the second embodiment of the present invention.

  As shown in FIGS. 2A to 2C, the detection electrode 11 has a structure formed by processing one metal micromesh into a cylindrical shape. However, in the present invention, the detection electrode 11 has a plurality of metal micromesh. It does not prevent that it is comprised from the laminated body of this, and using the metal sheet | seat without a mesh instead of metal micro meshes. The detection electrode 11 may be formed by processing a laminate of, for example, about 2 to 5 layers of metal micromesh.

  The dimensions of the detection electrode 11 are not particularly limited as long as the ozone water concentration can be measured. For example, the width w2 (cylindrical axial length) (see FIGS. 2A and 2C) is usually 5 to 15 mm, and the sensor From the viewpoint of further increasing the output, it is preferably 5 to 10 mm. Further, for example, the inner dimension t2 (cylindrical inner diameter) (see FIGS. 2A and 2B) is usually 3 to 10 mm, and preferably 3 to 8 mm from the viewpoint of further increasing the sensor output. Further, for example, the interval (distance) t3 (see FIG. 2B) between the detection electrode 11 and the comparison electrode 12 in the cylindrical part of the detection electrode 11 is usually 3 mm or less, preferably 2 mm or less, particularly 0.5 to 2 mm. is there.

  The metal that constitutes the detection electrode 11 is a metal that has a smaller ionization tendency than the metal that constitutes the comparison electrode 12, as in the detection electrode 1 in the first embodiment. For example, the detection electrode 11 has at least a surface of gold or It is composed of a gold plating layer or platinum or a platinum plating layer. The detection electrode 11 may be a so-called conductive diamond electrode.

  The thickness of one metal micromesh constituting the detection electrode 11 is preferably 0.05 mm to 0.2 mm. When a plurality of metal micromesh are used in a stacked manner, the thickness of the detection electrode 1 is 0. .3 mm to 1 mm is preferable.

  The comparison electrode 12 has a linear shape, and the diameter of the comparison electrode 12 is not particularly limited. For example, the comparison electrode 12 is 0.1 to 2 mm, and preferably 0.5 to 1 mm from the viewpoint of further increasing the sensor output. When the comparison electrode 12 has a coil shape, the outer diameter t4 (see FIG. 2B) is not particularly limited as long as it is smaller than the inner dimension t2 (mm) of the detection electrode 11, but preferably 0.5 × t2 to 0.8. Xt2. When the comparison electrode 12 has a coil shape, its axial length w3 (see FIG. 2C) is usually smaller than the width w2 (mm) of the detection electrode 11, and preferably 0.4 × w2 to 0.8 × w2. It is. The coil pitch of the comparison electrode 12 is not particularly limited, and is usually 0.5 to 2 mm, preferably 0.8 to 1.2 mm.

  The metal which comprises the comparison electrode 12 is a metal with a larger ionization tendency than the metal which comprises a detection electrode similarly to the comparison electrode 2 in a 1st embodiment, for example, is silver. The comparison electrode 12 may be one in which the surface of silver is protected with a conductive film. As a conductive film, the same thing illustrated as a conductive film of the comparative electrode 2 in a 1st embodiment is mentioned, for example.

A part of the lower end portion of the detection electrode 11 extends downward, the lead wire 4 is connected to the extension portion 11a, and the lead wire 4 is connected to the positive electrode of an ammeter (not shown). As the ammeter, a micro-ampere ammeter can be used.
A part of the lower end portion of the comparison electrode 12 extends downward, the lead wire 5 is connected to the extension portion 12a, and the lead wire 5 is connected to the negative electrode of the ammeter.

  The extension part 11 a of the detection electrode 11 and the extension part 12 a of the comparison electrode 12 are embedded in the base 6 and penetrate the lower surface of the base 6. That is, the detection electrode 11 and the comparison electrode 12 protrude from the upper surface of the base 6.

  As shown in FIG. 2D, the sealing member 7 has a through hole 101 formed in a wall surface 100 that forms a water passage serving as a passage for ozone water, and the base 6 is fitted into the through hole 101 to thereby adjust the ozone water concentration. This is to ensure water tightness between the through hole 101 and the base 6 when the sensor 20 is attached. FIG. 2D is a schematic cross-sectional view showing a usage state of the ozone water concentration sensor according to the second embodiment of the present invention.

  The ozone water concentration sensor 20 having the above configuration is immersed in, for example, ozone water flowing in a water passage or ozone water in a water tank to bring the detection electrode 11 and the comparison electrode 12 into contact with the ozone water. As a result, an electromotive force is generated, a stable electric signal having a strength proportional to the ozone concentration of ozone water is obtained, and the concentration of ozone water is measured.

  The relationship between the installation (direction) of the ozone water concentration sensor 20 and the flow direction of the ozone water is not particularly limited. When the ozone water concentration sensor 20 is installed in the direction shown in FIG. 2A, the flow direction of the ozone water is D1. Any direction of -D4 may be sufficient. In FIG. 2A, for example, when the flow direction of the ozone water is D1 or D3, the axial direction of the cylindrical shape of the detection electrode 11 is substantially perpendicular to the flow direction of the ozone water. Further, for example, when the flow direction of the ozone water is D2 or D4, the cylindrical axial direction of the detection electrode 11 is substantially parallel to the flow direction of the ozone water.

  From the viewpoint of further increasing the sensor output, the ozone water concentration sensor 20 is preferably installed so that the detection electrode is not obstructed from contacting the ozone water by the comparison electrode. That the detection electrode is not obstructed by the comparison electrode from contacting the flow of ozone water means that the most upstream part of the detection electrode is arranged at the same position as the most upstream part of the comparison electrode in the flow direction of the ozone water, or This means that the most upstream part of the detection electrode is arranged at a position upstream from the most upstream part of the comparison electrode (for example, D1, D3 or D4 in FIG. 2A). When the ozone water concentration sensor 20 is installed in the direction shown in FIG. 2A, the flow direction of the ozone water is preferably D1, D3, or D4, and more preferably D4. FIG. 2D is a schematic cross-sectional view showing the usage state of the ozone water concentration sensor when the flow direction of the ozone water is D4 in FIG. 2A.

  As described above, according to this embodiment, the detection electrode 11 is provided so as to surround the comparison electrode 12. By making the detection electrode 11 cylindrical, even if the size is made compact, ozone water can contact the detection electrode continuously and effectively without being blocked by the comparison electrode, so that the sensor output can be significantly increased. In particular, a sufficient sensor output can be obtained even at a water temperature of 15 ° C. or lower where the sensor output decreases. As a result, the bare electrode type ozone water concentration sensor 20 having high sensor performance can be obtained. Therefore, the ozone concentration can be accurately measured not only with ozone water having a conductivity of tap water level but also with ozone water having a very low conductivity such as pure water.

  In this embodiment (FIGS. 2A to 2D), the detection electrode 11 has a cylindrical shape and the comparison electrode 12 has a linear shape. However, both the detection electrode 11 and the comparison electrode 12 have a cylindrical shape (for example, a cylinder). Shape). For example, when both the detection electrode 11 and the comparison electrode 12 have a cylindrical shape, such an ozone water concentration sensor is different from that shown in FIGS. 2A to 2C except that the comparison electrode 12 has a cylindrical portion instead of the coil portion (spiral portion). This is the same as the 2D ozone water concentration sensor 20. The coil portion of the comparison electrode 12 in FIGS. 2A to 2D is a curved portion of the comparison electrode 12. The cylindrical portion of the comparison electrode 12 may be made of a metal micromesh. The metal micromesh of the cylindrical portion may be used alone, or may be used by overlapping two or more. Thus, when the comparative electrode 12 has a cylindrical portion, the dimensions of the cylindrical portion of the comparative electrode 12, that is, the outer diameter and axial length of the cylindrical portion, and the interval (distance) between the detection electrode 11 and the comparative electrode 12 are as follows. When the comparison electrode 12 has a coil shape, the outer diameter t4 (see FIG. 2B), the axial length w3 (see FIG. 2C), and the distance (distance) t3 between the detection electrode 11 and the comparison electrode 12 (see FIG. 2B). ).

(Measuring mechanism)
The ozone water concentration sensor of the present invention is classified as a “galvanic cell type sensor”. In the ozone water concentration sensor of the present invention, dissolved ozone is reduced on the detection electrode, and the ozone water concentration is measured by measuring the reduction current (output current) between the two electrodes flowing in proportion to the ozone water concentration. The generated output current is proportional to the area of the detection electrode and the ozone water concentration as shown in the following equation.

I: Output current indicating current (μA)
n: Number of electrons contained in electrode reaction F: Faraday constant (96,500 C / mol)
S: Area of detection electrode (cm ² )
C: Ozone water concentration of sample water (mg / L)

  For this reason, the area of the detection electrode in contact with the ozone water is increased, and the detection electrode is directly exposed to the ozone water. Accordingly, the sensor output can be increased, and the ozone concentration can be accurately measured even when the amount of ozone water is small, the temperature of the ozone water is low, or the ozone concentration of the ozone water is low.

[Ozone water concentration measuring device]
The present invention also provides an ozone water concentration measuring device having the ozone water concentration sensor.

  Hereinafter, the ozone concentration measuring apparatus of the present invention will be described in detail with reference to the drawings according to some embodiments, but various elements in the drawings are merely schematically and exemplarily shown for understanding of the present invention. First, the appearance and dimensional ratio may differ from the actual product. Unless otherwise specified, the same symbols or symbols indicate the same members or the same meaning.

(First embodiment)
The ozone water concentration measurement device 30 of this embodiment includes at least an ozone water holding container 31, a measurement cell 32, and a connection pipe 33, as shown in FIG. 3, for example, and usually further includes an ozone concentration detection substrate 34, a flow rate adjustment. A device 35 and a housing 36 are included. FIG. 3 is a schematic cross-sectional view of the ozone water concentration measuring apparatus according to the first embodiment of the present invention.

  The ozone water holding container 31 is a container for storing and holding ozone water. In FIG. 3, the ozone water holding container 31 protrudes and is installed vertically above the upper surface of the ozone water concentration measuring device, that is, is attached to the upper surface of a housing 36 to be described later. For example, as shown in FIG. 3, the ozone water holding container 31 may be attached so that the depth direction thereof is substantially parallel to the substantially vertical direction of the upper surface of the housing 36. The ozone water holding container 31 is not limited to this as long as ozone water can be supplied to the measurement cell 32 via a connection pipe 33 described later. For example, the ozone water holding container 31 may be housed in the housing 36. Even if the volume of the ozone water holding container 31 is 50 mL, the concentration of ozone water can be accurately measured. The said capacity | capacitance preferable from a viewpoint of a measurement precision is 100-300 mL. Of course, the volume may be 300 mL or more. The ozone water holding container 31 may be removable from the device 30 or may not be removable from the device 30.

  The measurement cell 32 is an electrochemical cell in which the ozone water concentration sensor (10, 20) described above is incorporated. An ozone water concentration sensor is installed in a predetermined direction in the flow path of the ozone water by the measurement cell 32. In FIG. 3, the ozone water concentration sensor (10, 20) is inserted upward from the bottom surface of the measurement cell 32, but contact between the ozone water concentration sensor detection electrode and the comparison electrode and the ozone water is achieved. For example, the ozone water concentration sensor (10, 20) may be inserted from the side surface or the upper surface of the measurement cell 32. From the viewpoint of further improving the measurement accuracy, the ozone water concentration sensor is preferably inserted upward from the bottom surface of the measurement cell 32. This is because it is possible to prevent the ozone reduction reaction from being inhibited by the retention of bubbles on the electrode surface.

  The connection pipe 33 is a pipe for communicating the ozone water holding container 31 and the measurement cell 32 and supplying ozone water to the measurement cell 32. The inner diameter of the connection pipe 33 is not particularly limited and is usually 3 to 10 mm, and preferably 3 to 7 mm from the viewpoint of dropping ozone water by its own weight.

  The ozone concentration detection substrate 34 has a function of converting an output current flowing between the detection electrode and the comparison electrode in the measurement cell 32 into an ozone concentration. The ozone concentration determined by the ozone concentration detection substrate 34 is usually displayed by a display device. As the display device, a digital display device, an analog display device, or density display using a plurality of light emitting diodes can be used. The display by the display device is usually based on an external power source.

  The flow rate adjusting device 35 is normally connected to a connection pipe 37 connected to the downstream side of the measurement cell 32. As the flow rate adjustment device 35, any device that can adjust the flow rate of ozone water by opening and closing the flow path may be used. For example, a manual valve, an electromagnetic valve, etc. are mentioned. The flow rate adjusting device 35 may be installed on the upstream side of the measurement cell 32, that is, may be installed between the ozone water holding container 31 and the measurement cell 32. Note that an orifice may be inserted between the measurement cell 32 and the flow rate adjusting device 35 to adjust the flow rate.

  The casing 36 is not particularly limited as long as it has a rigidity that can accommodate and carry the above-described components. As shown in FIG. 3, the housing 36 may include a lid portion 361 and a housing portion (main body portion) 362.

  In the ozone water concentration measuring device 30, ozone water is supplied to the ozone water holding container 31 with the flow rate adjusting device 35 closed. The ozone water is supplied from the ozone water holding container 31 to the measurement cell 32 through the connection pipe 33 by dropping the ozone water by its own weight (free fall) by opening the flow rate adjusting device 35 after the supply is completed. In the ozone water concentration sensor (10, 20) (galvanic cell type sensor) of the measurement cell 32, ozone is reduced when ozone water comes into contact with the detection electrode, a current flows between the comparison electrode, and the current flows. The ozone water concentration is converted into ozone water concentration by the ozone concentration detection substrate 34, and the ozone water concentration is displayed by a plurality of light emitting diodes or the like.

  The ozone water concentration measuring device 30 of the present embodiment is of a type that supplies ozone water to the measuring cell 32 by falling under its own weight. For this reason, both inside and outside the device (for example, the connection pipe 33). The connection pipe 37 is also not provided with a power mechanism such as a pump. Specifically, no power mechanism is provided on either the upstream side of the measurement cell 32 (between the ozone water holding container 31 and the measurement cell 32) or the downstream side of the measurement cell 32. For this reason, in the ozone water concentration measuring device 30, the surface of the ozone water in the ozone water holding container 31 is usually at a position higher than the inlet of the measurement cell 32. That is, the ozone water outlet of the ozone water holding container 31 is usually at a higher position than the inlet of the measurement cell 32. In the present specification, “self-weight drop” is a method of conveying and supplying ozone water to the measurement cell 32 only by potential energy, and a method of supplying ozone water without using mechanical energy such as a pump. It is.

  In this embodiment, even if ozone water is supplied to the measurement cell 32 by falling under its own weight, the ozone concentration can be accurately measured. Specifically, the supply flow rate to the measurement cell due to the dropping of ozone water by its own weight is usually 500 mL / min or less, particularly 50 to 500 mL / min, preferably 50 to 350 mL / min. In this embodiment, the ozone water concentration can be accurately measured even with such a small amount of ozone water supply flow rate.

  Since the ozone water concentration measuring device 30 of this embodiment can be supplied to the measuring cell by dropping the ozone water by its own weight, it does not necessarily require a power source, and the ozone water concentration measuring device can be easily reduced in weight and portability. it can.

  The ozone water concentration measuring device 30 of this embodiment can accurately measure the ozone water concentration even when the amount of ozone water is small, the temperature of the ozone water is low, or the ozone water concentration is low. .

  Since the bare electrode type ozone water concentration sensor is affected by the water temperature, it is preferable to display the ozone concentration corresponding to the water temperature by a water temperature changeover switch. For example, switching between when the water temperature is 15 ° C. or lower and when the water temperature is 15 ° C. or higher is possible.

  After the measurement of the ozone concentration is completed, so-called zero water having zero ozone water concentration, such as tap water or purified water, is passed through the measurement cell 32 into the ozone water holding container 31 to clean impurities remaining on the electrode surface. Thus, it is possible to measure quickly.

  The ozone water concentration measuring device 30 according to the present embodiment is not limited to the bare electrode method, and applies a constant voltage between the detection electrode and the comparison electrode, and measures the limit current generated by the reduction of the ozone water at the detection electrode. It can also be applied to polarographic ozone water concentration measurement.

(Second embodiment)
As shown in FIG. 4, the ozone water concentration measuring device 30a of the present embodiment is the first embodiment except that the ozone water holding container 31a is removable from the device 30a and the capacity can be changed as necessary. This is the same as the ozone water concentration measuring apparatus. FIG. 4 is a schematic sectional view of an ozone water concentration measuring apparatus according to the second embodiment of the present invention.

  The volume of the ozone water holding container 31a may be changed according to the amount of ozone water used for measurement. In addition, when increasing the capacity, if the height of the container is made extremely high, the water head of the retained water will change significantly, the supply flow rate of ozone water to the measurement cell will increase, and the sensor output will be increased, It is desirable to increase the cross-sectional area without changing the height of the container.

(Third embodiment)
As shown in FIG. 5, the ozone water concentration measurement device 30 c of this embodiment is the same as the ozone water concentration measurement device of the first embodiment, except that ozone water is supplied to the measurement cell 32 using the suction pump 38. It is. FIG. 5 is a schematic cross-sectional view of an ozone water concentration measuring apparatus according to the third embodiment of the present invention.

  In FIG. 5, the suction pump 38 is disposed downstream of the ozone water holding container 31 and upstream of the measurement cell 32 in the flow direction of ozone water, but is disposed downstream of the measurement cell 32. Also good. In FIG. 5, the suction pump 38 is built in the ozone water concentration measuring device 30c, but it may be placed outside. It is also possible to continuously measure the ozone concentration of ozone water by the suction pump 38.

  In the present embodiment, the ozone water holding container may not be used, and the ozone water may be directly sucked by the suction pump from the use point and supplied to the measurement cell 32.

  The ozone water concentration measuring devices 30, 30 a, 30 c of the first to third embodiments supply ozone water to the measurement cell 32 when measuring by any of the batch measurement method or the continuous measurement method. The ozone concentration of flowing ozone water can be detected and measured. The batch measurement method is a measurement method for measuring the ozone concentration of a pre-distributed amount of ozone water. For this reason, the batch measurement method is used to measure a ozone concentration by collecting a relatively small amount of ozone water below the capacity of the ozone water holding container 31, 31a in a beaker or the like and transferring it to the ozone water holding container 31, 31a. Is suitable. The continuous measurement method is a measurement method for measuring the ozone concentration of ozone water supplied continuously. For this reason, the continuous measurement method is suitable for measuring a change with time of the ozone water concentration with respect to the amount of ozone water exceeding the capacity of the ozone water holding containers 31 and 31a.

[Manufacture of ozone water concentration sensor]
Example 1
In this example, an ozone water concentration sensor 10 shown in FIG. 1A was manufactured.
A platinum-plated micro-grating laminate was used as the detection electrode 1. Specifically, the platinum-plated micro-grating is a 0.1 mm thick titanium plate that has been plated in a rhombus lattice (1 mm x 0.46 mm), and the surface is further plated with 2 μm thick platinum. It is. Three such platinum-plated micro gratings were stacked to form a detection electrode. The thickness does not change before and after the grating process.
A silver micro-grating laminate was used as the reference electrode 2. Specifically, the silver micro-grating is a silver thin plate having a thickness of 0.1 mm, which is subjected to a grating process in a rhombus lattice shape (1 mm × 0.46 mm). Four such silver micro-gratings were stacked to form a reference electrode.
As the insulator 3, a polyester cloth having a thickness of 0.1 mm was used.
The insulator 3 was folded so as to cover both surfaces of the comparative electrode 2, and the detection electrode 1 was folded so as to cover both surfaces of the insulator 3, thereby obtaining an ozone water concentration sensor 10. The insulator 3 and the detection electrode 1 are bent in a U shape at the tip of the comparison electrode 2.

  The dimensions of the ozone water concentration sensor 10 were approximately 12 mm in width w1 (see FIG. 1A) and approximately 12 mm in height h1 (see FIG. 1A).

  As shown in FIG. 1C, the ozone water concentration sensor 10 was installed and used so that the detection electrode 1 and the comparison electrode 2 were substantially parallel to the flow direction of the ozone water.

(Example 2)
In this example, an ozone water concentration sensor 20 shown in FIG. 2A was manufactured.
The detection electrode 11 was used alone without overlapping platinum-plated micro gratings. Specifically, the platinum-plated micro-grating is a 0.1 mm thick titanium plate that has been plated in a rhombus lattice (1 mm x 0.46 mm), and the surface is further plated with 2 μm thick platinum. It is. Such a platinum-plated micro grating was processed into a cylindrical shape as shown in FIGS. 2A to 2C to form a detection electrode.
A silver wire was used as the reference electrode 12. Specifically, a silver wire having a diameter of 0.8 mm was processed into a coil shape (spiral shape) having an outer diameter of 4 mm and a pitch of 1 mm as shown in FIGS.
The coiled comparison electrode 12 was disposed inside the cylindrical detection electrode 11 so as to be spaced apart from the detection electrode 11 to obtain an ozone water concentration sensor 20.

The width w2 (cylindrical axial length) of the detection electrode 11 was approximately 8 mm, and the inner dimension t2 (cylindrical inner diameter) was approximately 6 mm. The outer diameter t4 of the coil shape was approximately 4 mm, the axial length w3 (see FIG. 2C) was approximately 4 mm, and the coil pitch was approximately 1 mm.
The interval (distance) t3 between the detection electrode 11 and the comparison electrode 12 in the cylindrical portion of the detection electrode 11 was approximately 1 mm.

  As shown in FIG. 2D, the ozone water concentration sensor 20 is installed so that the most upstream part of the detection electrode 11 is arranged at a position upstream of the most upstream part of the comparison electrode 12 in the flow direction of the ozone water. Used. The coiled reference electrode was arranged at a position 1/2 on the downstream side of the cylindrical detection electrode in the flow direction of the ozone water.

(Comparative Example 1)
In this comparative example, an ozone water concentration sensor 200 shown in FIG. 9 was manufactured.
A platinum-plated micro-grating laminate was used as the detection electrode 201. Specifically, the platinum-plated micro-grating is a 0.1 mm thick titanium plate that has been plated in a rhombus lattice (1 mm x 0.46 mm), and the surface is further plated with 2 μm thick platinum. It is. Three such platinum-plated micro gratings were stacked to form a detection electrode.
A silver micro-grating laminate was used as the reference electrode 202. Specifically, the silver micro-grating is a silver thin plate having a thickness of 0.1 mm, which is subjected to a grating process in a rhombus lattice shape (1 mm × 0.46 mm). Four such silver micro-gratings were stacked to form a reference electrode.
As the insulator 203, a polyester cloth having a thickness of 0.1 mm was used.
The insulator 203 was folded so as to cover both surfaces of the detection electrode 201, and the comparison electrode 202 was folded so as to cover both surfaces of the insulator 203, whereby the ozone water concentration sensor 200 was obtained. The insulator 203 and the comparison electrode 202 are bent in a U shape at the tip of the detection electrode 201.

  The dimensions of the ozone water concentration sensor 200 were approximately 12 mm in width w ′ (see FIG. 9) and approximately 12 mm in height h ′ (see FIG. 9).

  The ozone water concentration sensor 200 was installed and used so that the detection electrode 201 and the comparison electrode 202 were substantially parallel to the flow direction of the ozone water, similarly to the ozone water concentration sensor 10 of Example 1.

[Evaluation 1]
The ozone water concentration sensor of Example 1 or Comparative Example 1 was incorporated into the measurement cell 32 of the ozone water concentration measuring device 30c shown in FIG. 5 to evaluate the ozone water concentration sensor. In order to investigate the influence of water temperature, tap water was used instead of ozone water, and the output characteristics of the sensor were examined. Specifically, an ozone water concentration sensor was placed in a water passage where tap water flows at a flow rate of 400 mL / min, and the sensor output was measured by changing the temperature of tap water. The results are shown in Table 1, Table 2 and FIG. In Table 1, Table 2, and FIG. 6, the sensor output is a relative value, and is a value when the sensor output at 11 ° C. in Comparative Example 1 is 10.

In the ozone water concentration sensor of Example 1, ozone water is directly contacted with the detection electrode and ozone is reduced. Therefore, the sensor output is higher than that of the sensor in which the detection electrode as in Comparative Example 1 is covered with the comparison electrode. was gotten. For this reason, in the ozone water concentration sensor of Example 1, the ozone concentration can be measured with sufficient accuracy with respect to a small amount of ozone water, low-concentration ozone water, and low-temperature ozone water.
In Comparative Example 1, since the detection electrode is covered with the comparison electrode, direct contact between the detection electrode and the ozone water is limited, and the sensor output is low particularly in a low flow rate condition.

[Evaluation 2]
The ozone water concentration sensor of Examples 1, 2 or Comparative Example 1 was incorporated into the measurement cell 32 of the ozone water concentration measuring device 30c shown in FIG. 5 to evaluate the ozone water concentration sensor. Specifically, an ozone water concentration sensor was placed in a water passage where ozone water of each concentration generated at 19 ° C. flows at a flow rate of 400 mL / min, and the sensor output was measured. The results are shown in Table 3, Table 4, Table 5, and FIG.

[Evaluation 3]
The ozone water concentration sensor of Example 1 was incorporated in the measurement cell 32 of the ozone water concentration measuring device 30 shown in FIG. 3 to evaluate the ozone water concentration sensor. Specifically, an ozone water concentration sensor was arranged in a water passage through which each concentration generated at 19 ° C. and a predetermined amount of ozone water flowed by its own weight fall, and the sensor output was measured. The results are shown in Table 6 and FIG.

  The ozone water concentration sensor and the ozone water concentration measuring device of the present invention are useful for measuring the ozone concentration in ozone water.

1:11: Detection electrode 2:12: Comparison electrode 3: Insulator 10:20: Ozone water concentration sensor 30: 30a: 30c: Ozone water concentration measuring device 31: Ozone water holding container 32: Measurement cell 33: Connection pipe 34 : Ozone concentration detection board 35: Flow rate adjustment device 36: Housing

Claims (11)

Comprising a detection electrode and a reference electrode made of metals having different ionization tendencies,
The reference electrode is disposed inside the detection electrode;
An ozone water concentration sensor, wherein the detection electrode is disposed so as to surround the comparison electrode. The detection electrode has a flat plate shape or a cylindrical shape,
The ozone water concentration sensor according to claim 1, wherein the comparison electrode has a flat plate shape, a cylindrical shape, or a linear shape. The ozone water concentration sensor further comprises an insulator having water permeability for preventing contact between the detection electrode and the comparison electrode,
The detection electrode and the comparison electrode have a flat plate shape,
The ozone water concentration sensor according to claim 1, wherein the ozone water concentration sensor has a structure in which the detection electrode covers the outside of the comparison electrode with the insulator interposed between the detection electrode and the comparison electrode. The detection electrode and the comparison electrode are composed of a metal micromesh,
The ozone water concentration sensor according to claim 3, wherein the insulator has a micromesh shape or a cloth shape.   The ozone water concentration sensor according to claim 3 or 4, wherein the detection electrode and the comparison electrode have a multilayer structure in which metal micromesh is laminated in multiple layers.   The ozone water concentration sensor according to any one of claims 3 to 5, wherein an interval between the detection electrode and the comparison electrode is 1 mm or less. The detection electrode has a cylindrical shape;
The reference electrode has a linear shape;
The ozone water concentration sensor according to claim 1, wherein the ozone water concentration sensor has a structure in which the comparison electrode is disposed inside the detection electrode so as to be separated from the detection electrode. The detection electrode is composed of a metal micromesh,
The ozone water concentration sensor according to claim 7, wherein the comparison electrode has a coil shape or a linear shape.   The ozone water concentration sensor according to claim 7 or 8, wherein a distance between the detection electrode and the comparison electrode is 2 mm or less. The detection electrode has at least a surface composed of gold or a gold plating layer or platinum or a platinum plating layer,
The ozone water concentration sensor according to any one of claims 1 to 9, wherein at least the surface of the comparison electrode is made of silver, silver chloride, or silver oxide.   An ozone water concentration measuring device comprising the ozone water concentration sensor according to claim 1.

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