Dissolved oxygen visualization device
The dissolved oxygen visualization device simplifies the measurement of dissolved and supersaturated oxygen through a sealed container and dimming control mechanism, allowing direct visual confirmation and quantitative evaluation, addressing the complexity and safety issues of existing methods.
Patent Information
- Authority / Receiving Office
- JP · JP
- Patent Type
- Patents
- Current Assignee / Owner
- 瀧和夫
- Filing Date
- 2021-12-20
- Publication Date
- 2026-05-21
AI Technical Summary
Existing methods for measuring dissolved oxygen in water are complex, require chemical instruments and reagents, pose safety risks, and do not allow for direct visual confirmation or simple quantitative evaluation, especially for children and inexperienced users.
A dissolved oxygen visualization device with a light receiving part and a light source part, featuring a sealed inspection container, a dimming control mechanism, and a supersaturated oxygen capture tube, allowing for visual confirmation and quantitative evaluation of dissolved and supersaturated oxygen without the need for chemical reagents or complex operations.
Enables easy, safe, and direct visual confirmation and quantitative evaluation of dissolved and supersaturated oxygen, simplifying the measurement process and eliminating the need for chemical handling, while providing accurate results under various water conditions.
Smart Images
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Abstract
Description
Technical Field
[0001] The present invention relates to a dissolved oxygen measuring device that enables simple visual confirmation of the presence of dissolved or supersaturated oxygen in water such as in the sea, lakes, rivers, or other liquids, and enables repeated measurement of its amount.
Background Art
[0002] The tactile confirmation of the presence of oxygen in water and the oxygen supply process can enhance people's awareness of environmental protection. Until now, the fact that "the same oxygen as in the atmosphere is dissolved in water" has remained as vague knowledge obtained through lectures, and tactile confirmation through vision has not been carried out in primary and secondary education. Therefore, at present, many people, including children and students, have not even reached the level of understanding this knowledge.
[0003] From the above, in recent water quality improvement projects using submerged plants and water quality conservation projects in fish farms, the selection of submerged plant species has often been based on experience, and it has been extremely rare to rely on a quantitative evaluation method of dissolved oxygen. Therefore, many water quality improvement projects have not achieved sufficient effects, and the awareness of the role of submerged plants in environmental conservation in coastal areas such as rivers, lakes, and dams has been low.
[0004] For the confirmation of the presence of dissolved oxygen in water, chemical analysis methods using chemical instruments such as test containers and burettes, and reagents such as dissolved oxygen oxidation-reduction agents have been used for many years. (See, for example, [Non-Patent Document 1]). Here, operations such as weighing reagents such as dissolved oxygen oxidation-reduction agents using a chemical balance and titration using a burette are not easy tasks for inexperienced children, students, or working adults.
[0005] For the evaluation of photosynthesis of submerged plants, etc., it is necessary to combine an over-saturated oxygen capture container with a sealed test container (light-receiving part) that encloses the submerged plants (see, for example, [Non-Patent Document 3]), and thus it has involved further complexity of the device.
[0006] In conventional testing equipment, transparent cylindrical containers with open tops are used as test containers, which makes them susceptible to dissolution of atmospheric oxygen, refraction and scattering of light at the container surface, and uneven lighting. Furthermore, for open cylindrical test containers, it was necessary to use an air-dissolution barrier agent such as petrolatum to prevent dissolution of atmospheric oxygen.
[0007] Furthermore, adjusting the light intensity for submerged plants often involves moving the light source near or far from the light-receiving unit (test container), which inevitably results in large-scale equipment. (See, for example, [Non-Patent Document 4])
[0008] Furthermore, both conventional colorimetric and instrumental measurement methods have made it difficult to continuously and sequentially confirm the presence of dissolved oxygen and the photosynthetic process of submerged plants visually. (See, for example, Patent Document 1.)
[0009] In addition, there is a colorimetric method that utilizes the chemical reaction of oxygen (see, for example, [Patent Document 1] and [Non-Patent Document 1]). These are simple quantitative methods and precise quantitative methods using instruments such as DO meters (see, for example, [Non-Patent Document 1]), and are not compatible with methods of intuitively confirming dissolved oxygen through visual inspection.
[0010] Furthermore, even simpler tests using pack tests involve cumbersome procedures such as having to extract the water sample from the test container. (For example, [Non-Patent Document 2])
[0011] Furthermore, conventional two-solution tests used to check dissolved oxygen require the preparation of a strong alkaline reducing agent and a corrosive / irritating oxidizing agent, which poses risks such as skin corrosion and irritation for children, students, and adults unfamiliar with handling chemicals. [Prior art documents] [Patent Documents]
[0012] [Patent Document 1] Japanese Patent Publication No. 50-104993 [Non-patent literature]
[0013] [Non-Patent Document 1] "Test Methods for Factory Wastewater - JIS K0102-2016," reviewed by the Japanese Industrial Standards Committee, published by the Japanese Standards Association, 2016, pp. 91-99. [Non-Patent Document 2] "Dissolved Oxygen (DO) Kit", Kyoritsu Chemical Laboratory Co., Ltd., URL: https: / / kyoritsu-lab.co.jp / products / az_do_10 [Non-Patent Document 3] "Photosynthesis Experiment with Aquatic Plants," produced by Gifu Prefectural River Environment Research Institute, p. 30. URL: http: / / www.cc.rd.pref.gifu.jp / fish [Non-Patent Document 4] "The Use and Effectiveness of ICT in Photosynthesis Lessons," Journal of Science Education Research, Vol. 54, No. 3, 2014. [Overview of the project] [Problems that the invention aims to solve]
[0014] The present invention aims to solve the problems described in
[0002] to
[0010] , and there was a need for the development of a simple device that would enable direct visual confirmation of phenomena and visual quantitative evaluation of supersaturated dissolved oxygen.
[0015] It was necessary to eliminate the combination of numerous general-purpose chemical instruments that plagued conventional inspection containers, as well as water leakage from instrument connections and the ingress and dissolution of air from the top of the open container.
[0016] Because of the refraction and scattering of light rays on the side of the inspection container described in
[0008] , the intensity of light from the light source and the intensity of light inside the container do not match, and there was a need to solve the shortcomings such as the fact that the relationship with the amount of photosynthesis of submerged aquatic plants is not always clear.
[0017] In an inspection container with an open top, there has been a need for a device to prevent residual air and supersaturated oxygen after using an air dissolution inhibitor from adhering as bubbles to the air dissolution inhibiting membrane serving as a lid, and a device that does not require cleaning of the inspection container after using the air dissolution inhibitor.
[0018] Furthermore, for the introduction of new instruments and the complexity of operation associated with the measurement of the amount of supersaturated oxygen described in
[0007] , there has been a need for the development of a device and method that enable simple quantitative evaluation.
[0019] In the investigation of the amount of photosynthetic activity of submerged plants described in
[0009] , there was a problem that the adjustment of the irradiation light intensity had to be done by changing the distance between the light source and the light receiving part (inspection container). Also, there has been a need to overcome drawbacks such as the light from the light source usually becoming diffused light.
[0020] Furthermore, in practical operations involving turbid water, there has been a need to develop a device that can adjust the light intensity on the surface of submerged plants under various turbid water environmental conditions without moving the light source or the light receiving part (inspection container).
Means for Solving the Problems
[0021] The device according to the present invention is a dissolved oxygen visualization device composed of at least a light receiving part unit for visually confirming the presence and amount of dissolved or supersaturated oxygen in the test water, and a light source part unit for creating the photosynthetic activity of submerged plants, and is capable of accommodating at least the test water and submerged plants.
[0022] Also, the light receiving part unit of the dissolved oxygen visualization device consists of an inspection container with an open top and a sealed lid for keeping the inside of the inspection container in a closed system. The inspection container has a nozzle at its lower part for connecting an indicator liquid supply mechanism and / or a pressure regulating mechanism. The sealed lid covers the upper part of the inspection container and is structured to create a sealed state where the test water stored in the inspection container is not in contact with the atmosphere.
[0023] In addition, it is desirable that the inspection container of the light receiving unit described in
[0022] has a transparent flat surface at least on the surface facing the light source unit.
[0024] The sealing lid of the inspection container described in
[0022] preferably has an inner surface that slopes downward with the center of the recess as the apex, and has an exhaust pipe that can be sealed at the apex.
[0025] A scale may be attached to the exhaust pipe provided at the apex of the sealing lid, and it may also serve as an oversaturated oxygen capture pipe for capturing and measuring oversaturated oxygen.
[0026] In addition, the light source unit described in
[0021] is composed of a light source and a collimating lens provided on the optical path between the light source and the inspection container facing the light source.
[0027] In the dissolved oxygen visualization device described in
[0021] , a dimming control mechanism may be provided, which is composed of a dimming plate provided on the optical path between the light source of the light source unit and the inspection container of the light receiving unit, a quantum sensor installed in the inspection container of the light receiving unit, and a light quantity controller that controls the light intensity transmitted through the dimming plate based on the output of the sensor.
Effect of the Invention
[0028] This dissolved oxygen visualization device can accommodate at least the test water and submerged plants, and is a simple unitization of a device for visually confirming the presence and amount of oxygen dissolved or oversaturated in the test water, and a light source unit for creating the photosynthetic activity of submerged plants. Therefore, an easy-to-operate device can be provided.
[0029] Furthermore, in the inspection container described in
[0022] , by installing a sealed lid on the inspection container with an open top, it is possible to easily create a sealed state that does not come into contact with the atmosphere. In addition, the pipe opening installed at the bottom of the inspection container allows for easy supply of indicator liquid to the closed inspection container and pressure regulation within the inspection container without the need for the complex preparation and operation of conventional methods.
[0030] Furthermore, since one side of the inspection container described in
[0023] is flat, unevenness in the light distribution inside the inspection container is eliminated, making it effective as an inspection container for quantitative evaluation for environmental restoration and the selection of submerged plant species in fish farms, etc.
[0031] Furthermore, by installing the airtight lid described in
[0024] on the test container, it is possible to solve the problems related to the complexity of preparing test and investigation equipment and the dissolution of oxygen from the atmosphere. Moreover, by using the airtight lid, the air dissolution barrier agent that was used in open-system containers becomes unnecessary, which is effective in simplifying the test procedure.
[0032] In addition, the installation of the supersaturated oxygen capture tube on the sealed lid of the test container described in
[0025] has the effect of simplifying the direct quantitative evaluation of the supersaturated oxygen amount measurement operation.
[0033] The formation of a light beam parallel to the optical axis as described in
[0026] creates conditions under which photosynthetic reactions in submerged aquatic plants can be carried out evenly. As a result, it is possible to efficiently set the reproduced light intensity to match the water quality environment of environmental improvement areas and aquaculture ponds, and to demonstrate the effectiveness of quantitative evaluation for the selection of submerged aquatic plants.
[0034] By incorporating a dimming control mechanism consisting of a dimming plate installed in the optical path between the light source of the light source unit and the inspection container of the light receiving unit, a photon quantum sensor installed inside the inspection container of the light receiving unit, and a light intensity controller that controls the intensity of light transmitted through the dimming plate based on the output of the sensor, the system effectively facilitates adjustment of light intensity under various turbid water environmental conditions without moving the light source or the light receiving unit (inspection container). [Brief explanation of the drawing]
[0035] [Figure 1] Front view of a dissolved oxygen visualization device illustrating an embodiment of the present invention. [Figure 2] Plan view of a dissolved oxygen visualization device illustrating an embodiment of the present invention. [Figure 3] Cross-sectional view of one embodiment of the light-receiving unit of a dissolved oxygen visualization device. [Figure 4-1] Conceptual diagram of the top of the sealed lid, and a cross-sectional view of one embodiment of a supersaturated oxygen capture tube installed on the top of the sealed lid. [Figure 4-2] Conceptual diagram of the top of the sealed lid, and a cross-sectional view of one embodiment of a graduated supersaturated oxygen capture tube installed on the top of the sealed lid. [Modes for carrying out the invention]
[0036] Hereinafter, embodiments of the present invention will be described with reference to Figures 1 to 4.
[0037] Figure 1 shows the light-receiving unit 1 and the light-light-emitting unit 3. The main components of the light-receiving unit 1 are the inspection container 4, the sealed lid 5 of the inspection container, the photoquantum sensor 6, and the supersaturated oxygen capture tube 7. The main components of the light-light-emitting unit 3 are the dimming plate 8, the light intensity controller 15, the parallel light lens 9, and the light source 10. Furthermore, the indicator liquid supply mechanism 2 consists of a three-way valve 12, a dissolved oxygen reaction indicator liquid storage container 18, and an indicator liquid injection valve 13. The dimming control mechanism 19 consists of the photoquantum sensor 6, the light intensity controller 15, and the dimming plate 8.
[0038] The inspection container 4 of the light-receiving unit 1 is an open-top container designed for easy insertion and removal of the inspection water, photon sensor 6, and submerged plants 11 shown in Figures 2 and 3. Furthermore, a sealed lid 5 is installed on top of the inspection container to prevent the dissolution of oxygen from the atmosphere.
[0039] This dissolved oxygen visualization device is capable of housing at least test water and submerged aquatic plants, and when determining the presence or absence of dissolved oxygen in the test water, the device configuration may consist of a light-receiving unit 1 and an indicator liquid supply mechanism 2 as shown in Figure 3. By placing the test water in the test container 4 of the light-receiving unit 1 and connecting the indicator liquid supply mechanism 2 to the test container 4, an objective, subjective evaluation of the dissolved oxygen contained in the test water can be provided through visual confirmation.
[0040] Furthermore, the test container 4 is capable of containing test water and submerged plants. When determining the photosynthetic activity of submerged plants, in addition to the configuration of the light-receiving unit 1 and indicator liquid supply mechanism 2 shown in Figure 2, a device configuration in which a light source unit 3 is connected allows for quantitative evaluation by visual confirmation of the presence and amount of oxygen.
[0041] Furthermore, the inspection container 4 is required to have at least one transparent surface, maintaining uniformity of the light intensity distribution within the inspection container due to the refraction and scattering of light rays at the side surface of the inspection container. This allows it to be provided as an inspection container for quantitative evaluation for the selection of submerged plant species in environmental restoration and fish farms, etc. In addition, it is desirable to install a three-port valve 12 at the bottom of the inspection container, connecting one end to the indicator liquid supply mechanism 2 and the other end to the top-open type narrow tube 13.
[0042] Here, the sealed lid 5 of the inspection container 4 is further designed so that its inner surface is concave, with a vertex at the center, as shown by the dashed lines in Figures 4-1 and 4-2. Residual air remaining in the concave inner surface of the sealed lid 5 is removed by a sealable exhaust pipe 7 installed at the vertex of the sealed lid 5.
[0043] Furthermore, any residual air remaining at the top of the inspection container can be easily removed along with excess water by simply placing the sealed lid 5 so that it sinks along the inner surface of the inspection container 4. This eliminates the need for additional sealing of the top surface of the inspection container 4.
[0044] Here, the exhaust pipe 7 is interchangeable with the sealed lid: the valved exhaust pipe shown in Figure 3 when only evaluating the presence of dissolved oxygen is required; the valved supersaturated oxygen capture tube 7 shown in Figure 4-1 when qualitative evaluation of the amount of supersaturated oxygen due to photosynthesis by submerged aquatic plants is required; and the graduated supersaturated oxygen capture tube 20 shown in Figure 4-2 is required when quantitative evaluation of the amount of supersaturated oxygen is required. The graduated supersaturated oxygen capture tube 20 facilitates objective quantitative evaluation of the amount of supersaturated oxygen produced by submerged aquatic plants, and its use in a wide range of projects such as ecosystem restoration and fish farms is desired.
[0045] Next, by providing a dimming control mechanism 19 consisting of a dimming plate 8 installed in the optical path between the light source of the light source unit 3 and the inspection container of the light receiving unit 1 as shown in Figures 1 and 2, a photon quantum sensor 6 installed inside the inspection container of the light receiving unit, and a light intensity controller 15 that controls the transmitted light intensity of the dimming plate based on the output of the sensor, it is possible to easily adjust the light intensity under various turbid water environmental conditions without moving the light source or the light receiving unit (inspection container).
[0046] Here, the light source unit 3 consists of a light source 10, a parallel light lens 9 that arranges the light from the light source into a parallel beam of light rays, and a dimming control mechanism 19 for adjusting the amount of light. The parallel light lens 9 prevents uneven photosynthesis by submerged plants. It is desirable to select and use a light source 10 that has a photon flux density suitable for photosynthesis in submerged plants (visible region with light intensity of 400-700 nm).
[0047] The parallel light rays that pass through the dimming plate 8 are irradiated perpendicularly onto the side of the inspection container. The dimming control mechanism 19 described in
[0052] consists of a photon sensor 6, a dimming plate 8, and a light intensity controller 15 for controlling the light intensity of the dimming plate. The light-reducing control mechanism 19 allows for adjustment of the amount of photon flux density on the surface of submerged aquatic plants, enabling adjustment of the light intensity on the surface of submerged plants under various turbid water environmental conditions without moving the light source or light-receiving unit (inspection container), even in practical applications involving turbid water. By incorporating a light-reducing plate 8, such as a polarizing plate, into the light-reducing control mechanism 19, the intensity of the irradiated light can be adjusted under various water turbidity conditions in conjunction with the photon flux density sensor 6 inside the inspection container, resulting in simple device operation. Alternatively, the light-reducing control mechanism 19 can also utilize physical light-shielding plates, liquid light-shielding plates with variable turbidity concentration, or polarizing plates. Furthermore, it is desirable to shield the dissolved oxygen visualization device from light so that it is not affected by ambient light sources.
[0048] The following describes the method for visually confirming dissolved oxygen and quantitatively evaluating the amount of supersaturated dissolved oxygen based on the operation of the above configuration. The main components of the indicator supply mechanism 2 shown in Figure 2 are the dissolved oxygen reaction indicator storage container 18 and the indicator injection valve 13 shown in Figure 3.
[0049] To visually confirm the presence of dissolved oxygen in the test water, approximately 300 mL of dissolved oxygen reaction indicator solution is placed in the dissolved oxygen reaction indicator solution storage container 18 of the indicator solution supply mechanism 2, and the test water is filled into the test container 4 of the light receiving unit 1. Next, a sealing lid 5 is inserted from the top of the test container, and after confirming that the test container is sealed, the three-port valve 12 installed at the bottom of the test container 4 is opened, and the indicator solution injection bubble 13 of the indicator solution supply mechanism 2 is gradually opened to inject an appropriate amount. At that time, it is confirmed that the dissolved oxygen in the test water reacts with the indicator solution and the test solution turns blue.
[0050] Furthermore, when examining only dissolved oxygen in the test water, the combination of the light-receiving unit 1 and the indicator liquid supply mechanism 2 is used. By injecting an appropriate amount of dissolved oxygen reaction indicator liquid 18 from the indicator liquid supply mechanism 2 into the test water in the test container 4 using the indicator liquid injection bubble 13, the presence of dissolved oxygen can be visually confirmed by the blue coloration of the test water.
[0051] In investigating the photosynthetic activity of submerged aquatic plants, similar to visually confirming the presence of dissolved oxygen, approximately 300 mL of dissolved oxygen reaction indicator solution is placed in the dissolved oxygen reaction indicator solution storage container 18 of the indicator solution supply mechanism 2. The photoquantum sensor 6, the submerged aquatic plant to be tested 11, and oxygen-free water are placed in the test container 4 of the light receiving unit 1, and the test container 4 is sealed with the airtight lid 5. Next, the three-port valve 12 installed at the bottom of the test container 4 is opened, and the indicator solution injection bubble 13 of the indicator solution supply mechanism 2 is gradually opened to inject an appropriate amount. Once it is confirmed that the test solution does not change color, the test container 4 is quickly kept in a light-shielded state. It is desirable to provide a thin tube for pressure adjustment in the three-port valve 12.
[0052] Here, the installation of a stirring device 17 such as a magnetic stirrer 16 allows for the efficient and even distribution of the dissolved oxygen reaction indicator solution throughout the test container 4.
[0053] Next, the light source 10 of the light source unit is turned on. The light from the light source 10, passing through the parallel light lens 9 and the dimming plate 8, irradiates the submerged aquatic plants 11 in the inspection container 4, which has been unshielded. At this time, the oxygen produced by photosynthesis becomes dissolved oxygen, gradually changing the water in the inspection container 4 to blue from the vicinity of the submerged aquatic plants, thus visually confirming the phenomenon of dissolved oxygen production by the submerged aquatic plants. Then, it becomes supersaturated and is collected as gaseous oxygen in the supersaturated oxygen capture tube 7, as illustrated in Figure 4-1. Furthermore, by using a supersaturated oxygen capture tube 20 with a volume scale, as illustrated in Figure 4-2, quantitative evaluation of the photosynthetic activity of the submerged aquatic plants becomes possible.
[0054] Furthermore, when examining only dissolved oxygen in the test water, the combination of the light-receiving unit 1 and the indicator liquid supply mechanism 2 is used. By injecting an appropriate amount of dissolved oxygen reaction indicator liquid 18 from the indicator liquid supply mechanism 2 into the test water in the test container 4 using the indicator liquid injection bubble 13, the presence of dissolved oxygen can be visually confirmed by the blue coloration of the test water.
[0055] Here, by incorporating a light-reducing plate 8, such as a polarizing plate, into the light-reducing control mechanism 19, the intensity of the irradiation light can be adjusted in conjunction with the photon sensor 6 inside the inspection container under various water turbidity conditions, thereby simplifying the operation of the device. Alternatively, the light-reducing control mechanism 19 can also utilize a physical light-shielding plate or a liquid light-shielding plate with variable turbidity concentration.
[0056] For the apparatus according to the present invention to function effectively, it is desirable to use a one-solution dissolved oxygen reaction indicator, and this addresses the problems described in
[0002] to
[0006] ,
[0010] and
[0011] below, and is in line with the purpose of the apparatus, which enables the quantitative determination of the photosynthetic activity of submerged aquatic plants or the presence of dissolved oxygen in the test water by simple operation of a one-solution dissolved oxygen reaction indicator through reduction and oxidation reactions with dissolved oxygen.
[0057] Furthermore, even in the handling of dissolved oxygen indicators, whether for inserting evaluation equipment or performing simple tests using pack tests, the operation was complicated, similar to the case where two indicator solutions were used, as it required extracting the water sample from the test container first. (See, for example, [Non-Patent Document 2])
[0058] Conventional methods for confirming the presence of dissolved oxygen require unfamiliarity with handling chemical equipment and weighing chemicals, as well as the use of two liquids that undergo multiple chemical reaction steps. Therefore, there was a need for the development of an indicator that is easy to handle.
[0059] Furthermore, there was a need for the development of a dissolved oxygen indicator that would enable the non-extraction of test water and the simple, continuous evaluation of the oxygen production process by photosynthesis in submerged aquatic plants.
[0060] The dissolved oxygen indicator used in this invention requires the effective use of oxidizing and reducing agents with different chemical titers, as well as a color-developing agent that changes color depending on the presence or absence of dissolved oxygen.
[0061] The dissolved oxygen indicator is a single solution that causes the color of the color-developing agent to change upon contact with the dissolved oxygen in the test water. To adjust the color of the color-developing agent used in the dissolved oxygen indicator, oxygen already bound to the color-developing agent is removed with an alkaline reducing agent, and any excess reducing agent is adjusted by titration with an oxidizing agent.
[0062] This solution eliminates the complexity of the titration and back-titration procedures and the risks associated with reagents in conventional two-solution methods for determining dissolved oxygen using oxidizing and reducing agents. Furthermore, it reduces the need for meticulous handling of chemical equipment and reagents, as well as the specialized knowledge and costs associated with using such equipment and extracting water samples, by simply injecting a single solution into the test water. This makes it a highly convenient indicator solution for beginners with limited experience handling chemical equipment and for businesses whose daily work involves selecting submerged aquatic plants.
[0063] Currently, methods for quantifying dissolved oxygen include the Winkler method and its variations, the Alsterberg method, the Rideal-Stewart method, the Pomeroy-Kirschman method, the alkaline hypochlorite method, the alum method, the Miller method, the Amidol method, gas analysis, electrical measurement methods, and the Standard color paper method. Of these, macroscopic colorimetric methods, such as the Winkler method and its variations, are considered the best for quantification based on color changes.
[0064] Here, colorimetric quantitative methods such as the Amidol method all seem to require complex reagents and procedures, making them unsuitable as field measurement methods. Also, the oldest proposed method Free While the standard color paper method for colorimetrically measuring iodine is considered a simple method, it has drawbacks in terms of color tone because the standard paper is prone to discoloration. Furthermore, gas analysis and electrical measurement methods rely on measuring instruments, which differs from the macroscopic colorimetric method.
[0065] The Winkler method and its variations, the Alsterberg method, the Rideal-Stewart method, the Pomeroy-Kirschman method, the alkaline hypochlorite method, the alum method, and the Miller method differ in their indicator or coloring method depending on the presence of dissolved oxygen.
[0066] Typical indicators include anthocyanins, which are acid-base indicators that turn reddish in acidic conditions and bluish in basic conditions; pelargonidin, which is bright red in neutral solutions; anidin, which is purple; and delphinidin, which is purplish-red. Other indicators include cyanidin, which changes to red under acidic conditions and to blue or blue-green under basic conditions; flavonoids, whose pigment color changes with pH; and methylene blue, which is blue in the oxidized state but becomes colorless when reduced.
[0067] Furthermore, regarding the method of coloring or decolorizing the indicator with dissolved oxygen contained in the test water, there are two methods: one involves mixing an alkaline solution with the test water, adding the coloring indicator, and then back-titrating with an acidic solution for quantification; and the other involves titrating a solution in which the coloring indicator is dissolved with an acidic solution to an alkaline solution obtained by reacting with dissolved oxygen in the test water. This method quantifies dissolved oxygen under the characteristics of the color change of indicators, as described above.
[0068] A method that allows for easy evaluation of the presence of dissolved oxygen in test water by injecting a single dissolved oxygen reaction indicator offers greater convenience compared to the conventional two-solution method using an oxidizing agent and a reducing agent. Furthermore, it provides the benefit of visually evaluating the dissolved oxygen contained in water, or the process of oxygen production through photosynthesis.
[0069] The following describes examples of the one-component dissolved oxygen indicator of the present invention. In the dissolved oxygen reaction indicator supply mechanism, the confirmation of the presence of dissolved oxygen using only one liquid as described in
[0060] and
[0061] eliminates the need for two liquids, an oxidizing agent and a reducing agent, as in the conventional method, and also eliminates the need for the preparation of chemical equipment, the measurement of reagents, and specialized knowledge of equipment use. This ease of use makes it a highly convenient indicator solution for beginners with little experience handling equipment and chemicals, as well as for businesses whose daily work involves selecting submerged plants.
[0070] Here, the color change of the dissolved oxygen reaction indicator is due to an oxidizing agent that reacts with dissolved oxygen and produces color, and a reducing agent that undergoes a decolorization reaction. For example, this method utilizes the fact that colorless leucomethylene blue is oxidized by dissolved oxygen and changes to blue methylene blue.
[0071] Furthermore, as a specific example, a methylene blue solution consisting of sodium hydroxide and glucose is mixed with 5 mL of sodium tartrate-sodium hydroxide solution / 50 mL of water as a dissolved oxygen oxidizing agent. Ammonium iron(II) sulfate solution is then back-titrated and added dropwise as a reducing agent until the blue color of the methylene blue disappears, and the endpoint is reached when the leucomethylene blue becomes colorless and transparent again, thus creating a one-solution dissolved oxygen reaction indicator.
[0072] In this dissolved oxygen visualization device, the dissolved oxygen reaction indicator solution turns blue through a chemical reaction with dissolved oxygen in the test water, thereby revealing the presence of dissolved oxygen. Furthermore, the oxygen production process by photosynthesis in submerged plants is directly observed and evaluated by monitoring the changes in the dissolved oxygen reaction indicator solution over time.
[0073] In summary, by integrating the conventionally used submerged plant storage container with the supersaturated oxygen generation measuring device, the introduction of additional equipment becomes unnecessary, while simultaneously simplifying the operation method for measuring supersaturated oxygen levels and promoting direct quantitative evaluation. [Explanation of Symbols]
[0074] 1. Light-receiving unit 2 Indicator liquid supply mechanism 3. Light source unit 4. Test container 5 Sealing lid 6. Quantum light sensor 7. Supersaturated oxygen capture tube 8. Dimming plate 9 Parallel light lens 10 light source 11 Submerged plants 12 Three-mouthed valve 13. Indicator solution injection bubble 14 Exhaust port with valve 15 Light intensity controller 16 Magnetic Stirrer 17. Stirring device 18. Dissolved oxygen reaction indicator storage container 19. Dimming control mechanism 20 Graduated Supersaturated Oxygen Capture Tubes
Claims
[Claim 1] It consists of a light-receiving unit having a test container capable of containing at least test water and submerged plants, and a light-emitting unit having a light source, The inspection container has one transparent side that receives light from the light source, The lower part of the inspection container is provided with a pipe opening for connecting an indicator liquid supply mechanism via a three-port valve. The aforementioned three-port valve is connected to an open-topped narrow tube. The indicator liquid supply mechanism is connected to an oxygen reaction indicator liquid storage container containing dissolved oxygen reaction indicator liquid. The indicator liquid supply mechanism is equipped with an indicator liquid injection valve for discharging the dissolved oxygen reaction indicator liquid contained in the oxygen reaction indicator liquid storage container, The dissolved oxygen reaction indicator solution is injected into the test container by the indicator solution supply mechanism to visualize the dissolved oxygen in the test water. After injecting the dissolved oxygen reaction indicator solution into the test container using the indicator solution supply mechanism, the photosynthetic activity of the submerged plants in the test container is visualized by irradiating them with light from the light source. A dissolved oxygen visualization device characterized by the following features.