Microbubble generating device and water apparatus

Abstract

Provided is a microbubble generator and a water device that can efficiently generate microbubbles. The microbubble generator is characterized by including: an electrolytic cell having a water inlet and a water outlet, and an electrode provided inside; and a control unit that controls the application of electricity to the electrode, thereby generating microbubbles in the electrolytic cell, wherein the control unit applies electricity to the electrode when water flows into the electrolytic cell from the inlet and flows out from the outlet.

Description

Technical Field

[0001] Generally speaking, the present invention relates to a microbubble generating device and a water-using device. Background Technology

[0002] Electrolysis of water containing chloride ions produces bubbles. In a microbubble generator, the efficient generation of microbubbles is desired.

[0003] Patent documents Non-Patent Literature 1: Analysis of Microbubble Flow Generated During Electrolysis of NaCl Solution, Proceedings of the Hokkaido Branch of the Japan Society of Civil Engineers, 2015, No. 72 Summary of the Invention

[0004] This invention is based on the understanding of such a problem, and its purpose is to provide a microbubble generating device and water equipment that can efficiently generate microbubbles.

[0005] The first invention is a microbubble generating device, characterized by comprising: an electrolytic cell having a water inlet and an outlet, and an electrode disposed inside; and a control unit for controlling the energization of the electrode, thereby generating microbubbles in the electrolytic cell, wherein the control unit energizes the electrode when water flows into the electrolytic cell from the inlet and flows out from the outlet.

[0006] According to this microbubble generator, when water flows in the electrolytic cell, electricity is applied to the electrodes, thereby efficiently generating microbubbles.

[0007] The second invention is a microbubble generating device, characterized in that, in the first invention, it further includes a flow rate regulating unit for regulating the flow rate of water in the electrolytic cell.

[0008] According to this microbubble generating device, the flow rate in the electrolytic cell can be made to a flow rate that easily generates microbubbles in water.

[0009] The third invention is a microbubble generating device, characterized in that, in the second invention, when the control unit energizes the electrode, the flow rate regulating unit regulates the flow rate of water between the electrodes to 0.28 m / s or more.

[0010] According to this microbubble generator, more microbubbles can be easily generated in water.

[0011] The fourth invention is a microbubble generating device, characterized in that, in the third invention, when the control unit energizes the electrode, the flow rate regulating unit regulates the average flow rate of the water between the electrodes to 0.28 m / s or more and 0.84 m / s or less.

[0012] According to this microbubble generator, more microbubbles can be easily generated in water.

[0013] The fifth invention is a microbubble generating device, characterized in that, in the second invention, the flow rate regulating unit is a pressure regulating valve located upstream of the electrolytic cell.

[0014] According to this microbubble generating device, it is possible to suppress fluctuations in the flow rate of water supplied to the electrolyzer.

[0015] The sixth invention is a microbubble generating device, characterized in that, in any one of the inventions 1 to 3, the control unit controls the effective chlorine concentration in the water electrolyzed by the electrolytic cell to be 0.1 ppm or more and 5.0 ppm or less.

[0016] According to this microbubble generator, the number of bubbles can be easily changed by controlling the current to the electrodes. Furthermore, it can meet standards such as those in the World Health Organization (WHO) drinking water quality guidelines and those based on the Japanese Waterworks Law.

[0017] The seventh invention is a microbubble generating device, characterized in that, in any one of the inventions 1 to 3, the electrolytic cell has an electrode comprising: a substrate containing at least one of titanium and titanium alloys; and a catalyst layer disposed on the substrate and containing platinum group elements, wherein the control unit generates water containing the microbubbles and hypochlorous acid by electrolyzing the water through energizing the electrode.

[0018] The bactericidal effect of hypochlorous acid can be obtained using this microbubble generating device.

[0019] The eighth invention is a water-using device, characterized by comprising: a microbubble generating device according to any one of the inventions 1 to 3; and a water discharge section that discharges water flowing out from the outlet in a mist form, wherein, under the control of the control section, the bubbles contained in the water electrolyzed by the electrolytic cell are only bubbles with a volume equivalent diameter smaller than the average particle size of the mist water discharged by the water discharge section.

[0020] According to this water-using equipment, it is expected to suppress, for example, large air bubbles that cause the mist-like water discharge from the water outlet to become unstable.

[0021] According to the present invention, a microbubble generating device and a water-using device that can efficiently generate microbubbles are provided. Attached Figure Description

[0022] Figure 1 This is a block diagram illustrating the water-using equipment involved in the embodiment. Figure 2 (a) ~ Figure 2 (c) is a schematic diagram illustrating the evaluation method for the number of bubbles. Figure 3 This is a schematic diagram illustrating the evaluation method for the number of bubbles. Figure 4 This is a graph illustrating the relationship between available chlorine concentration and number concentration. Figure 5 This is a graph illustrating the relationship between flow rate and number concentration. Figure 6 This is a histogram illustrating the particle size distribution of bubbles in electrolyzed water. Figure 7 This is a histogram illustrating the particle size distribution of bubbles in electrolyzed water. Figure 8 This is a histogram illustrating the particle size distribution of bubbles in electrolyzed water. Figure 9 This is a histogram illustrating the particle size distribution of bubbles in electrolyzed water. Figure 10 This is a histogram illustrating the particle size distribution of bubbles in electrolyzed water. Figure 11 This is a schematic diagram showing the area near the electrode surface of an electrolytic cell in electrolysis. Figure 12 This is a graph comparing different methods for evaluating bubbles. Figure 13 This is an example of a curve showing the particle size of bubbles based on image analysis and laser diffraction and scattering methods. Figure 14 (a) and Figure 14 (b) is a histogram illustrating the particle size distribution of bubbles in electrolyzed water. Figure 15 (a) and Figure 15 (b) is a histogram illustrating the particle size distribution of bubbles in electrolyzed water. Figure 16 (a) and Figure 16 (b) is a histogram illustrating the particle size distribution of bubbles in electrolyzed water. Figure 17 (a) and Figure 17 (b) is a histogram illustrating the particle size distribution of bubbles in electrolyzed water. Figure 18 (a) and Figure 18 (b) is a histogram illustrating the particle size distribution of bubbles in electrolyzed water. Symbol Explanation 11-Water stop valve; 12-Solenoid valve; 13-Flow rate regulating unit; 15-Electrolytic cell; 15a-Inlet; 15b-Outlet; 15e-Electrode; 16-Water discharge unit; 17-Control unit; 18-Flow path; 20-Micro bubble generator; 21-Water tank; 22, 23-Hose; 24-Black plate; 25-Light source; 26-Camera; 29-Shooting range; 40-Bubble; 100-Water-using equipment. Detailed Implementation

[0023] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Furthermore, in each drawing, the same reference numerals are used to denote the same constituent elements, and detailed descriptions are omitted where appropriate. Figure 1 This is a block diagram illustrating the water-using equipment involved in the embodiment. like Figure 1 As shown, the water-using device 100 according to the embodiment includes a microbubble generator 20 and a water discharge section 16. The microbubble generator 20 includes a solenoid valve 12, a flow rate regulating section 13, an electrolytic cell 15, and a control section 17. The water-using device 100 is a device that uses water supplied from the upstream side of the stop valve 11 to generate functional water and discharges the generated functional water from the water discharge section 16.

[0024] Furthermore, the components of the water-using equipment 100 do not necessarily have to be housed in the same enclosure; they can be installed separately. For example, the water discharge section 16 can be installed separately from the frame housing the electrolysis tank 15.

[0025] Specifically, examples of water-using appliances include urinals, fixtures installed in bathrooms or bathtubs (such as prefabricated bathrooms), automatic faucet systems, vanity units, prefabricated kitchens, toilets, or sanitary cleaning devices installed in toilets.

[0026] The water-discharging section 16 is, for example, a device with a water outlet, and may also include a nozzle. For example, cleaning is performed by water discharged from the water-discharging section 16. For example, when the water-using appliance 100 is a urinal, the water-discharging section 16 discharges functional water into the urinal as cleaning water. For example, when the water-using appliance 100 is a fixture installed in a bathroom or bathtub, the water-discharging section 16 discharges water onto the floor of the wash area. The water-discharging section 16 may also include a shower head. For example, when the water-using appliance 100 is a vanity, the water-discharging section 16 discharges water into the basin. For example, when the water-using appliance 100 is a kitchen unit, the water-discharging section 16 discharges water into the sink. For example, when the water-using appliance 100 is a toilet, the water-discharging section 16 discharges functional water into the toilet as cleaning water.

[0027] like Figure 1As shown, in the water flow path 18 from the water discharge section 16, the following components are arranged sequentially from upstream: water supply source (not shown), water stop valve 11, solenoid valve 12, flow rate regulating section 13, electrolytic cell 15 and water discharge section 16.

[0028] A stop valve 11 opens and closes the flow path 18 between the water supply source and the solenoid valve 12. The stop valve 11 switches between supplying and stopping water to the solenoid valve 12. The water supply source is, for example, a tap water pipe. That is, tap water is supplied to the solenoid valve 12, the flow rate regulating unit 13, and the electrolytic cell 15, for example. Water containing chloride ions is supplied to the solenoid valve 12, the flow rate regulating unit 13, and the electrolytic cell 15, for example.

[0029] Between the stop valve 11 and the flow rate regulating unit 13, the solenoid valve 12 opens and closes the flow path 18. The solenoid valve 12 switches the water supply and shut-off to the flow rate regulating unit 13 and the electrolytic cell 15. Water is supplied to the electrolytic cell 15 from the solenoid valve 12 via the flow rate regulating unit 13.

[0030] Electrolyzer 15 is a device that converts water supplied from upstream into functional water. The functional water generated by electrolyzer 15 is water containing microbubbles. The functional water generated by electrolyzer 15 can also be water containing microbubbles and having a bactericidal function. For example, electrolyzer 15 has: a microbubble generation function that generates microbubbles in water; and a bactericidal function generation function that imparts bactericidal function to water through electrolysis. The bactericidal function generation function is, for example, the function of electrolyzing tap water to generate water with bactericidal function (bactericidal water). The water discharge section 16 discharges the functional water generated by electrolyzer 15.

[0031] The sterilization function can enhance the chemical cleaning effect, for example. The microbubbles can enhance the physical cleaning effect, for example. Water containing microbubbles and having a sterilization function is discharged from the water outlet 16, thereby improving the cleaning performance through the combined effects of sterilization and microbubbles.

[0032] Disinfecting water may contain disinfecting ingredients. Specifically, disinfecting water can be ozone water, water containing hypochlorous acid, water containing hydrogen peroxide, or water containing silver ions.

[0033] For example, through electrolysis, water containing chloride ions, such as tap water, can be converted into water containing hypochlorous acid. Electrolytic cell 15, for example, generates water containing hypochlorous acid by electrolyzing tap water.

[0034] Alternatively, the electrolytic cell 15 may also have electrodes that dissolve bactericidal metal ions (such as silver ions) into the tap water by electrolyzing it. For example, an external voltage is applied between the anode and cathode containing silver (or a silver-containing metal) to electrolyze the water flowing between the anode and cathode, thereby releasing silver ions from the anode into the water.

[0035] The fine bubbles generated by the fine bubble generation function of the electrolytic cell 15 are bubbles with a volume-equivalent diameter of less than 100 µm. Herein, bubbles with a volume-equivalent diameter of less than 100 µm are referred to as Fine Bubble (registered trademark, Chinese: micro-nano bubbles, omitted hereinafter). Micro-nano bubbles are divided into micro bubbles and Ultra Fine Bubble (registered trademark, Chinese: ultra-fine bubbles, omitted hereinafter). Micro bubbles are micro-nano bubbles with a volume-equivalent diameter of not less than 1 µm and less than 100 µm. Ultra-fine bubbles are micro-nano bubbles with a volume-equivalent diameter of less than 1 µm. The definition of Bubble conforms to Japanese Industrial Standard JIS B 8741-1:2019. Both micro bubbles and ultra-fine bubbles can also be generated through the fine bubble generation function.

[0036] In this example, the sterilizing water is hypochlorous acid-containing water. The electrolytic cell 15 has a pair of electrodes. For example, the pair of electrodes are in a flat plate shape arranged in parallel opposite to each other. In this example, the arithmetical mean height Sa of the electrode surface (specified by the International Organization for Standardization ISO 25178 standard) is about 0.2 µm (not less than 0.15 µm and not more than 0.25 µm). The electrodes of the electrolytic cell 15, for example, comprise: a substrate containing at least one of titanium and a titanium alloy; and a catalyst layer disposed on the substrate and containing a platinum group element. In this example, the catalyst layer is iridium oxide or the like. A voltage is applied between the pair of electrodes to energize the electrodes, and tap water flowing between the electrodes is electrolyzed. Hypochlorous acid is generated from chloride ions in the tap water. The cleaning performance can be improved through the sterilization effect of hypochlorous acid.

[0037] In addition, the fine bubble generation function of the electrolytic cell 15 is a function of generating fine bubbles by electrolyzing chloride ion-containing water such as tap water. For example, the electrolytic cell 15 electrolyzes tap water, thereby generating fine bubbles in the liquid inside the electrolytic cell 15. In the aforementioned electrolysis for generating hypochlorous acid, gases such as H₂ and O₂ are generated on the surface of the electrodes, for example. The generated gases separate from the electrodes and become fine bubbles in water.

[0038] Thus, in this example, the electrolytic cell 15 electrolyzes tap water to generate sterilizing water and fine bubbles at the same time, thereby generating sterilizing water containing fine bubbles.

[0039] The control unit 17 is, for example, a control circuit including a central processing unit (CPU) or the like. The control unit 17 controls the operations of the solenoid valve 12 and the electrolytic cell 15. That is, the control unit 17 controls the opening and closing of the solenoid valve 12. The control unit 17 switches between energizing and de-energizing the electrodes of the electrolytic cell 15. Through the energization control on the electrodes of the electrolytic cell 15, the control unit 17 electrolyzes the water in the electrolytic cell 15 to generate fine bubbles in the electrolytic cell 15.

[0040] The electrolytic cell 15 has an inlet 15a into which water from upstream flows; and an outlet 15b into which water flows downstream. Water flowing in from the inlet 15a passes between electrodes where electrolysis generates hypochlorous acid and microbubbles, and then flows out from the outlet 15b. When the control unit 17 controls the solenoid valve 12, etc., so that water flows into the electrolytic cell 15 from the inlet 15a and simultaneously flows out from the outlet 15b, it controls the energization of the electrodes in the electrolytic cell 15 to electrolyze the water, thereby generating hypochlorous acid and microbubbles in the water.

[0041] According to the inventors' research, it is known that when electricity is applied to the electrodes while water is flowing within the electrolytic cell 15, microbubbles can be generated efficiently. For example, the force generated by the water flow within the electrolytic cell 15 makes it easier for bubbles generated on the electrode surface of the electrolytic cell 15 to detach from the electrode surface. For example, the bubbles detach from the electrode surface before growing to a diameter of 100 μm or more, becoming microbubbles in the water.

[0042] The flow rate regulating unit 13 regulates the flow rate of water within the electrolytic cell 15. The flow rate regulating unit 13 can also be a flow rate regulating unit that regulates the flow rate within the electrolytic cell 15. The flow rate regulating unit can be, for example, a flow rate regulating valve such as a throttle valve. The flow rate regulating unit 13 may also include a flow rate regulating valve (such as a solenoid valve) that can be controlled by the control unit 17. Not limited to this, the flow rate regulating unit 13 can be any device capable of regulating the flow rate of water within the electrolytic cell 15 in any manner.

[0043] The flow rate regulation unit 13 adjusts the flow rate between the electrodes (near the electrode surface) of the electrolytic cell 15. For example, by providing the flow rate regulation unit 13, it is possible to achieve water discharge at the most suitable flow rate during the generation of microbubbles. Furthermore, although the flow rate regulation unit 13 is provided upstream of the electrolytic cell 15 in this example, it can also be provided downstream of the electrolytic cell 15.

[0044] The water jet section 16 sprays water containing microbubbles and possessing bactericidal properties (emitting it in a mist). Since the bactericidal water containing microbubbles is emitted in a mist, water splashing can be expected to be suppressed, for example. Furthermore, the average particle size of the mist water can be, for example, approximately 200 μm or more and 1500 μm or less. The average particle size mentioned here is based on the Schott average (total volume / total surface area) of the particle size distribution obtained by Fraunhofer analysis using a He-Ne laser, and is a concept referred to as equivalent diameter.

[0045] The concentration of the bactericidal component (effective chlorine concentration) in the functional water can be adjusted, for example, by the current applied to the electrodes of the electrolysis cell 15. For example, the higher the current, the higher the effective chlorine concentration. Moreover, as explained below, by adjusting the flow rate between the electrodes of the electrolysis cell 15 (near the electrode surface) and the effective chlorine concentration in the functional water, the concentration (number of microbubbles per unit volume), the size of the microbubbles, etc., can be adjusted.

[0046] The evaluation of the number of bubbles generated by electrolysis in the electrolytic cell is explained. Figure 2 (a) ~ Figure 2 (c) and Figure 3 This is a schematic diagram illustrating the evaluation method for the number of bubbles. Figure 2 (a) is the front view. Figure 2 (b) is a side view. Figure 2 (c) is the top view. Although not shown in the diagram, hose 22 is connected to the outlet 15b of electrolytic cell 15. Electrolysis in electrolytic cell 15 generates water containing bubbles and hypochlorous acid (electrolyzed water). The electrolyzed water generated in electrolytic cell 15 is supplied to water tank 21 through hose 22. Hose 23 has a suction port for drawing electrolyzed water from water tank 21 to maintain the water level in water tank 21.

[0047] A black plate 24 is installed inside the water tank 21. Electrolyzed water is released from the outlet of the hose 22 between the black plate 24 and the wall (front glass) of the water tank 21. A light source 25 is installed below the water tank 21 to illuminate the interior of the water tank 21.

[0048] Air bubbles passing through the gap (1.1 mm) between the black plate 24 and the water tank 21 are photographed. Specifically, the camera 26 photographs the area 29 between the black plate 24 and the wall of the water tank 21 using the wall of the water tank 21. Images of the air bubbles located within the photographing area 29 are captured. The number (concentration) of air bubbles in the electrolyzed water is evaluated by analyzing the captured images. Figure 3 This is an example of a captured image.

[0049] More detailed evaluation criteria are as follows. <1. Device Structure> • Use a glass water tank with internal dimensions of 94 mm wide × 140 mm high × 61 mm deep. • Prepare a black plate by coating the back side of the soda-lime glass plate with black paint. This black plate will serve as the background for the captured image. • Attach the black board to another smooth board that will become the main body of the black board. • A 0.28mm thick brass plate is used as a gasket and sandwiched between the main plate and the glass water tank. Adjust the number of shims so that the gap between the glass water tank and the black plate (uncoated surface) is about 1.1mm. The flow path consists of a polyurethane hose with an inner diameter of 2.99 mm and a total length of approximately 2800 mm, a small pump, and an electrolytic cell (TOTO model: TCM1451). • Add purified water to a 5L plastic water tank and dissolve an amount of sodium chloride corresponding to the target effective chlorine concentration. • Power is supplied to the small pump and the electrolytic cell respectively through a regulated power supply. • Illuminate from below the glass water tank using a flat panel light. • Use a digital camera (Olympus, Tough TG-6). • Camera shooting settings Shooting mode: Microscope mode (macro photography) ISO sensitivity: 12800 Aperture value: F4.5 Focal length: 9mm Metering mode: -2.0 Shutter speed: 160 / 200 / 250 / 320 (※This will be automatically set according to the brightness of the subject, depending on the camera specifications) Pixel size: 4000×3000 Compression ratio: 1 / 2.7 • When shooting, cover the glass water tank and the entire digital camera equipment with a light-blocking cloth to minimize the influence of light other than the flat panel light. <2. Preparation> • If air bubbles have formed and are attached to the glass tank and black plate, they may hinder the shooting, so they should be cleaned beforehand. First, sand with 2000-grit alumina sandpaper, then clean with an alkaline cleaning agent, and finally replace the remaining water with purified water. This results in higher hydrophilicity. After cleaning, use foam material, clips, and gaskets to fix the position of the black plate on the front of the glass water tank. • Secure the spout with foam material and clips. Position the water nozzle so that it sprays water directly into the shooting area through the gap between the glass water tank and the black plate. • Use a clip to fix the water inlet at a position about 30mm from the top of the glass water tank. <3. Shooting Conditions> • The shooting angle is approximately 11.1mm horizontally × 8.4mm vertically (calculated value). • When shooting in flowing water, the flow of bubbles will create a motion blur, so immediately capture the moment when the water stops flowing. • Take 3 shots under each condition. <4. Electrolysis> • Set the voltage / current value of the regulated power supply connected to the small pump in a manner that determines the specified flow rate. • Set the voltage / current value of the regulated power supply connected to the electrolytic cell in a manner that determines the effective chlorine concentration. • A small pump on the suction side used to maintain the water level is always driven at a voltage / current value that sufficiently prevents water overflow. <5. Image Analysis> • Image analysis is performed on captured images using a self-developed program (Python) that can calculate the number and size of particles. Import the image file (4000×3000 pixels) into the program as a grayscale image and serialize the pixel information numerically. The grayscale image uses values ​​from 0 to 255 (black to white) to represent the brightness level. • Implement binarization with a threshold set to 70. • Perform two morphological transformations to eliminate tiny noise areas (white) and fill defects (black) within the bubble area. • For areas (white) where two or more bubbles overlap and are photographed, the watershed algorithm identifies them as different particles. • Count each bubble particle. At this point, the number of pixels for each bubble particle is also output, allowing the particle size to be calculated from the dimensions within the image. The number and size distribution of bubbles in the image are output as analysis results. <6. Processing of Analysis Results> • Under the same shooting angle, a ruler conforming to the Japanese Industrial Standard JIS Class 1 precision was photographed separately and its size was calibrated to calculate the bubble size. • Convert the volume of the shooting area to 1 ml and calculate the number concentration per 1 mL.

[0050] Figures 4 to 10 Indicates based on about Figures 2-3 Evaluation of the electrolyzed water method described above. Figure 4 This is a graph illustrating the relationship between available chlorine concentration and number concentration. Available chlorine concentration (ppm (mg / L)) corresponds to the concentration of hypochlorous acid in the electrolyzed water. The available chlorine concentration was measured using the DPD method. A portable residual chlorine meter DR300 (manufactured by Toa DKK Corporation) was used for measurement, and free chlorine reagent (manufactured by HACH) was used as the measuring reagent. Number concentration is the number of bubbles per unit volume of electrolyzed water. Figure 4The diagram shows the electrolysis process with water flowing into the electrolytic cell 15 at flow rates of 200cc / min, 500cc / min, and 1000cc / min. Figure 4 This represents data when the available chlorine concentration is 0 ppm, 0.3 ppm, 1 ppm, 5 ppm, and 10 ppm.

[0051] As from Figure 4 As is known, the lower the flow rate, the higher the number concentration of bubbles. Furthermore, when the available chlorine concentration is greater than 0 ppm and less than 5.0 ppm, the number concentration of bubbles tends to increase with increasing available chlorine concentration. On the other hand, if the available chlorine concentration is greater than 5.0 ppm, the increase in number concentration tends to be slightly slower relative to the increase in available chlorine concentration.

[0052] For example, in this embodiment, the control unit 17 energizes the electrodes of the electrolyzer 15 such that the effective chlorine concentration in the water electrolyzed by the electrolyzer 15 is greater than 0 ppm (e.g., 0.1 ppm or more) and less than 5.0 ppm. Therefore, the number of bubbles can be easily changed, for example, by controlling the electrode current value. That is, for example, when the effective chlorine concentration is greater than 0 ppm and less than 5.0 ppm, the number of fine bubbles (e.g., microbubbles) in the electrolyzed water changes linearly with respect to the effective chlorine concentration. Furthermore, it can meet standards such as the World Health Organization (WHO) drinking water quality guidelines. For example, it can meet the benchmark of an effective chlorine concentration of 0.1 ppm or more at the terminal water supply tap as stipulated in the Enforcement Regulations of the Japanese Waterworks Law.

[0053] Figure 5 This is a graph illustrating the relationship between flow rate and number concentration. Figure 5 This indicates that the effective chlorine concentration in the electrolyzed water generated in the electrolyzer 15 with water flowing at various flow rates is 3 ppm and 5 ppm.

[0054] The bubble number concentration is lowest at a flow rate of 70 cc / min. The bubble number concentration tends to peak at a flow rate of around 100 cc / min. As the flow rate increases from 100 cc / min, the bubble number concentration tends to decrease. This is believed to be because increasing the flow rate decreases the electrolysis efficiency and reduces the number of bubbles per unit volume. Preferably, the flow rate in the electrolytic cell 15 is between 100 cc / min and 600 cc / min. For example, the microbubble generator 20 produces functional water with a microbubble concentration of 5000 (bubbles / mL) or higher, preferably 10000 (bubbles / mL) or higher. The microbubble concentration of the functional water can also be 35000 (bubbles / mL) or lower.

[0055] Figures 6-10 This is a histogram illustrating the particle size distribution of bubbles in electrolyzed water. A histogram represents the number of bubbles (particles) per 10 μm of bubble diameter. For example, the number of particles at the 40 μm mark on the horizontal axis represents the number of bubbles with a diameter greater than 30 μm and less than 40 μm. Furthermore, the particle diameter can also be considered as the volume equivalent diameter assuming a spherical shape.

[0056] Figure 6 This refers to the case where the flow rate in electrolytic cell 15 is 70cc / min. Figure 7 This refers to the case where the flow rate in electrolytic cell 15 is 100cc / min. Figure 8 This refers to the case where the flow rate in electrolytic cell 15 is 300cc / min. Figure 9 This refers to the case where the flow rate in electrolytic cell 15 is 500cc / min. Figure 10 This refers to the case where the flow rate in electrolytic cell 15 is 1000cc / min. The flow velocity between the electrodes of the electrolytic cell 15 can be calculated by dividing the flow rate between the electrodes of the electrolytic cell 15 by the cross-sectional area of ​​the flow path. For example, when the flow rate is 100 cc / min, the calculated flow velocity is 0.28 m / s. For example, when the flow rate is 300 cc / min, the calculated flow velocity is 0.84 m / s.

[0057] Figures 6-10 These figures represent the cases where the effective chlorine concentration in the electrolyzed water generated in the electrolyzer 15 at various flow rates is 3 ppm and 5 ppm, respectively. The modal particle size is the most frequent value of the particle number.

[0058] As from Figure 6 and Figure 7 As is known, if the flow rate increases from 70 cc / min to 100 cc / min, the number of particles increases dramatically. For example, a flow rate of 100 cc / min or higher is preferred. As a result, more microbubbles can be generated in the water.

[0059] Assuming the total number of particles remains constant, an increase in flow rate leads to an increase in water volume, therefore it is speculated that the number of bubbles per unit volume of water tends to decrease. Conversely, when the flow rate is above 100 cc / min, the number of particles increases compared to 70 cc / min. Furthermore, as... Figure 6 As shown, when the flow rate is 70 cc / min, the modal particle size is 50–60 μm (or 60–70 μm). In contrast, as shown... Figure 7 As shown, when the flow rate is above 100 cc / min, the modal particle size is relatively small, ranging from 30 to 40 μm. Thus, in the range where the flow rate is less than 100 cc / min, for example, if the flow rate increases, the modal particle size will be relatively small, and the total number of particles will increase.

[0060] On the other hand, such as Figures 8-10 As shown, when the flow rate is above 100 cc / min (300 cc / min, 500 cc / min and 1000 cc / min), the modal particle size is maintained at around 30 to 40 μm. In the range of flow rates above 100 cc / min, relatively more particles of around 30 to 40 μm can be generated.

[0061] In addition, as mentioned above Figure 5 As shown, it is known that if the flow rate is greater than 300 cc / min, the number concentration will decrease. For example, a flow rate of 100 cc / min or more and 300 cc / min or less is more preferred. That is, a flow velocity of 0.28 m / s or more and 0.84 m / s or less is more preferred.

[0062] For example, when the control unit 17 supplies power to the electrodes of the electrolytic cell 15, the flow rate regulating unit 13 regulates the average flow rate of the water between the electrodes to 0.28 m / s or more and 0.84 m / s or less, thereby generating more microbubbles in the water.

[0063] As a flow rate regulating unit 13, a pressure regulating valve may be used, for example. (Regarding...) Figure 1 As explained, the flow rate regulating unit 13 is located upstream of the electrolyzer 15. By using such a flow rate regulating unit 13, for example, even if the primary side pressure changes, fluctuations in the flow rate of water supplied to the electrolyzer 15 can be suppressed. For example, regardless of changes in the primary side pressure, the supply flow rate to the electrolyzer 15 can be maintained at a stable, predetermined value. Furthermore, for example, since the primary side pressure acts on the upstream side of the flow rate regulating unit 13, damage to the electrolyzer 15 can be prevented. Moreover, not limited to the above, the flow rate regulating unit 13 does not necessarily have to be located upstream of the electrolyzer 15, but can also be located downstream of the electrolyzer 15.

[0064] Figure 11 It is a schematic diagram showing the area near the electrode surface of the electrolytic cell in electrolysis. Tap water is electrolyzed in electrolytic cell 15, thereby generating bubbles 40 on the surface of electrode 15e. Larger bubbles 40 are more likely to detach from electrode 15e. For example, it is assumed that if the particle size of bubble 40 reaches approximately 40 μm, it will easily detach from electrode 15e. Furthermore, the detachment of bubbles 40 from electrode 15e can be regulated by adjusting the flow rate (velocity). For example, if the flow rate (velocity) is higher, bubbles 40 will easily detach from electrode 15e. For example, it is assumed that when the flow rate is approximately 0.28 m / s or higher, bubbles 40 will easily and stably detach from electrode 15e. The size or concentration of bubbles in the electrolyzed water will change with the flow rate. Furthermore, for example, if bubbles 40 are difficult to detach from electrode 15e or if the bubble 40 grows too quickly, the bubbles 40 become larger than micro / nano bubbles, making it difficult to increase the number of microbubbles. If the flow rate is too high, the water volume will increase, and therefore the number of bubbles per unit volume of water may decrease.

[0065] For example, in the control of the electrolyzer 15 to generate functional water by the control unit 17, the air bubbles contained in the water electrolyzed by the electrolyzer 15 (the water flowing out from the outlet 15b) can be only air bubbles with a particle size smaller than the average particle size of the mist water discharged from the water discharge unit 16. Thus, for example, it can be expected to suppress the instability of the mist water discharge from the water discharge unit 16 due to larger air bubbles.

[0066] Regarding the evaluation methods for bubbles, besides those related to... Figure 2 and Figure 3 In addition to the evaluation methods already described (hereinafter referred to as image analysis methods), there is also the laser diffraction and scattering method. The laser diffraction and scattering method is a measurement method based on the International Organization for Standardization (ISO) standards. (Refer to...) Figures 12-18 The measurement methods are compared and explained. Furthermore, in both measurement methods, the water flow rate of the electrolyzer is kept the same, and the electrolyzed water that generates bubbles under the same effective chlorine concentrations (0 ppm, 0.3 ppm, 1 ppm, 5 ppm, 10 ppm) is evaluated. A Shimadzu SALD7500nano analyzer was used in the laser diffraction and scattering method.

[0067] Figure 12 This is a graph comparing different methods for evaluating bubbles. Figure 12 In this study, the evaluation data for the number of microbubbles were compared between those obtained through image analysis and those obtained through laser diffraction and scattering. The correlation coefficient (R²) between the two measurement methods was 0.944, confirming a very high correlation. This indicates that the number concentration obtained through image analysis is consistent with the number concentration obtained through the commonly used laser diffraction and scattering method. Therefore, the image analysis method is considered to possess sufficient measurement accuracy.

[0068] Figure 13 This is an example of a curve showing the particle size of bubbles based on image analysis and laser diffraction and scattering methods. Figure 14 (a) Figure 15 (a) Figure 16 (a) Figure 17 (a) and Figure 18 (a) is a histogram illustrating the particle size distribution of bubbles in water electrolysis based on laser diffraction and scattering. Figure 14 (b) Figure 15 (b) Figure 16 (b) Figure 17 (b) and Figure 18 (b) is a histogram illustrating the particle size distribution of bubbles in electrolyzed water based on image analysis.

[0069] Figure 14 (a) and Figure 14 (b) shows the particle size distribution during water electrolysis with an available chlorine concentration of 0.3 ppm. Figure 15 (a) and Figure 15 (b) shows the particle size distribution during water electrolysis with an available chlorine concentration of 1 ppm. Figure 16 (a) and Figure 16 (b) shows the particle size distribution during water electrolysis with an available chlorine concentration of 3 ppm. Figure 17 (a) and Figure 17 (b) shows the particle size distribution during water electrolysis with an available chlorine concentration of 5 ppm. Figure 18 (a) and Figure 18 (b) shows the particle size distribution during water electrolysis with an effective chlorine concentration of 10 ppm. The flow rate of the electrolyzer is 200 cc / min.

[0070] As from Figure 13 As can be seen, regardless of the measurement method, the average and median are both around 40 μm. Furthermore, as from... Figure 14 (a) ~ Figure 18 As can be seen from (b), regardless of the measurement method, the modal particle size (most frequent value) is 30–40 μm, exhibiting the same tendency. It is believed that the image analysis method can achieve the same measurement accuracy as the laser diffraction-scattering method.

[0071] This embodiment may also include the following configuration. (Component 1) A microbubble generator, characterized in that, It features: an electrolytic cell with a water inlet and outlet, and electrodes installed inside; The control unit controls the energizing of the electrodes, thereby generating microbubbles within the electrolytic cell. When water flows into the electrolytic cell from the inlet and flows out from the outlet, the control unit energizes the electrode. (Component 2) The microbubble generating device described in configuration 1 is characterized by further comprising a flow rate regulating unit for regulating the flow rate of water in the electrolytic cell. (Component 3) The microbubble generating device described in configuration 2 is characterized in that, when the control unit energizes the electrode, the flow rate regulating unit regulates the average flow rate of the water between the electrodes to 0.28 m / s or more. (Component 4) The microbubble generating device described in configuration 3 is characterized in that, when the control unit energizes the electrode, the flow rate regulating unit regulates the average flow rate of the water between the electrodes to 0.28 m / s or more and 0.84 m / s or less. (Component 5) The microbubble generating device described in configuration 2 is characterized in that the flow rate regulating unit is a pressure regulating valve located upstream of the electrolytic cell. (Composition 6) The microbubble generating device comprising any one of 1 to 5 is characterized in that the control unit controls the effective chlorine concentration in the water electrolyzed by the electrolytic cell to be 0.1 ppm or more and 5.0 ppm or less. (Component 7) The microbubble generating apparatus comprising any one of items 1 to 6 is characterized by, The electrolytic cell has electrodes comprising: a substrate containing at least one of titanium and titanium alloys; and a catalyst layer disposed on the substrate and containing platinum group elements. The control unit generates water containing microbubbles and hypochlorous acid by electrolyzing the water through the electrode. (Composition 8) A water-using device, characterized in that, It includes: a microbubble generating device as described in any one of components 1 to 7; The water discharge section sprays out water from the outlet in a mist-like manner. Under the control of the control unit, the air bubbles contained in the water electrolyzed by the electrolytic cell are only air bubbles with a volume equivalent diameter smaller than the average particle size of the mist water discharged by the water discharge unit.

[0072] The embodiments of the present invention have been described above. However, the present invention is not limited to these descriptions. Regarding the foregoing embodiments, any design modifications made by those skilled in the art that possess the features of the present invention are also included within the scope of the present invention. For example, the shape, size, material, configuration, and arrangement of the elements are not limited to the illustrated contents, but can be appropriately modified. Furthermore, as long as it is technically feasible, the elements of the aforementioned embodiments can be combined, and as long as they contain the features of the present invention, the combined technology is also included within the scope of the present invention.

Claims

1. A microbubble generator, characterized in that, It features: an electrolytic cell with a water inlet and outlet, and electrodes installed inside; The control unit controls the energizing of the electrodes, thereby generating microbubbles within the electrolytic cell. When water flows into the electrolytic cell from the inlet and flows out from the outlet, the control unit energizes the electrode.

2. The microbubble generator according to claim 1, characterized in that, It also includes a flow rate regulating unit for regulating the flow rate of water in the electrolytic cell.

3. The microbubble generator according to claim 2, characterized in that, When the control unit supplies power to the electrode, the flow rate regulating unit adjusts the average flow rate of the water between the electrodes to 0.28 m / s or higher.

4. The microbubble generator according to claim 3, characterized in that, When the control unit energizes the electrode, the flow rate regulating unit adjusts the average flow rate of the water between the electrodes to be above 0.28 m / s and below 0.84 m / s.

5. The microbubble generator according to claim 2, characterized in that, The flow rate regulating unit is a pressure regulating valve located upstream of the electrolytic cell.

6. The microbubble generator according to any one of claims 1 to 3, characterized in that, The control unit controls the effective chlorine concentration in the water electrolyzed by the electrolyzer to be above 0.1 ppm and below 5.0 ppm.

7. The microbubble generator according to any one of claims 1 to 3, characterized in that, The electrolytic cell has electrodes comprising: a substrate containing at least one of titanium and titanium alloys; and a catalyst layer disposed on the substrate and containing platinum group elements. The control unit generates water containing microbubbles and hypochlorous acid by electrolyzing the water through the electrode.

8. A water-using device, characterized in that, It possesses: the microbubble generating device according to any one of claims 1 to 3; The water discharge section sprays out water from the outlet in a mist-like manner. Under the control of the control unit, the air bubbles contained in the water electrolyzed by the electrolytic cell are only air bubbles with a volume equivalent diameter smaller than the average particle size of the mist water discharged by the water discharge unit.

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