JP7738220B2 - Hypochlorous acid water supply device and space sterilization system using the same - Google Patents

Description

The present invention relates to a hypochlorous acid water supply device that supplies hypochlorous acid water in which the residual components of NaClO and NaOH, which are produced by electrolyzing salt water, have been reduced, and to an air sterilization system that uses the same.

Conventionally, electrolysis of saltwater produces hypochlorous acid water, which contains NaClO as its main component and also HClO and NaOH. It is known that making hypochlorous acid water weakly acidic improves its disinfecting power, and a technology is known for controlling the pH of the water to the weakly acidic side using an ion-permeable membrane. (See, for example, Patent Document 1.)

Japanese Patent Application Publication No. 8-164392

However, simply adjusting the pH to a weak acidity does not adequately suppress the formation of residual components, NaClO and NaOH. NaClO and NaOH are components that remain on the surface as solids even after the hypochlorous acid water evaporates, and these residual components deliquesce and redissolve in water, which can accelerate metal corrosion. Therefore, when hypochlorous acid water containing a large amount of NaClO and NaOH is sprayed as a mist, tiny residual components accumulate, raising concerns about corrosion over long-term use.

The present invention aims to solve the above-mentioned conventional problems and provide a hypochlorous acid water supply device that can supply hypochlorous acid water with reduced residual components generated by the electrolysis of salt water.

To achieve this objective, the system is equipped with a hypochlorous acid water generation unit that continuously electrolyzes hypochlorous acid water from salt water supplied into a serpentine, membrane-less electrolysis flow path by passing current between a pair of first cathode and anode electrodes, and a hypochlorous acid water treatment unit that continuously treats the hypochlorous acid water supplied from the hypochlorous acid water generation unit into each of the serpentine, membrane-equipped electrolysis flow paths by passing current between a pair of second cathode and anode electrodes, and the hypochlorous acid water discharged from the electrolysis flow path on the anode side of the hypochlorous acid water treatment unit is supplied to the outside.

The present invention provides a hypochlorous acid water supply device that can supply hypochlorous acid water with reduced residual components generated by the electrolysis of salt water.

FIG. 1 is a cross-sectional image diagram of a hypochlorous acid water supply device according to a first embodiment of the present invention. FIG. 2 is a schematic diagram of a hypochlorous acid water generation unit. FIG. 3 is an exploded perspective view of the hypochlorous acid water generation unit. FIG. 4 is a vertical cross-sectional image diagram of the hypochlorous acid water generation unit. FIG. 5 is a horizontal cross-sectional image diagram of the hypochlorous acid water generation unit. FIG. 6 is a schematic diagram of a hypochlorous acid water treatment unit. FIG. 7 is an exploded perspective view of the hypochlorous acid water treatment unit. FIG. 8 is a vertical cross-sectional image diagram of the hypochlorous acid water treatment unit. FIG. 9 is a horizontal cross-sectional image diagram of the hypochlorous acid water treatment unit. FIG. 10 is a diagram showing the relationship between the characteristics of hypochlorous acid water that has flowed through the hypochlorous acid water supply device and the electrodialysis time. FIG. 11 is a schematic diagram of a space sterilization system using a hypochlorous acid water supply device according to the second embodiment of the present invention.

The hypochlorous acid water supply device of the present invention comprises a hypochlorous acid water generation unit that continuously electrolyzes hypochlorous acid water from salt water supplied into a serpentine, membrane-less electrolysis flow path by passing current between a pair of first cathode and anode electrodes, and a hypochlorous acid water treatment unit that continuously treats the hypochlorous acid water supplied from the hypochlorous acid water generation unit into each of the serpentine, membrane-equipped electrolysis flow paths by passing current between a pair of second cathode and anode electrodes, and is configured to supply hypochlorous acid water discharged from the electrolysis flow path on the anode side of the hypochlorous acid water treatment unit to the outside.

With this configuration, hypochlorous acid water is generated by electrolyzing saltwater in a membrane-less electrolysis flow path in the hypochlorous acid water generation unit, and then the hypochlorous acid water generated in the membrane-less electrolysis flow path is circulated through a membrane-equipped electrolysis flow path in the hypochlorous acid water treatment unit, allowing hypochlorous acid water to be extracted from the positive electrode side with reduced cations that cause residual components. This allows for a one-pass hypochlorous acid water supply device that can supply hypochlorous acid water from which residual components resulting from the electrolysis of saltwater have been separated to the outside.

In addition, in the hypochlorous acid water supply device according to the present invention, the membrane-less electrolysis flow path is configured to include a planar first anode, a planar first cathode facing the first anode, and a spacer member provided between the first anode and first cathode. The pair of first cathode-and-cathode electrodes are configured in a serpentine shape by exposing the first anode and first cathode to the membrane-less electrolysis flow path via the spacer member. In this way, the ability to electrolyze brine can be changed by changing the flow path shape formed in the spacer member, allowing the area and time for electrolyzing brine to be freely designed.

In the hypochlorous acid water supply device according to the present invention, the membrane-equipped electrolysis flow path includes a serpentine first flow path in which a second positive electrode is exposed and extends along the flow path, a serpentine second flow path facing the first flow path and in which a second negative electrode is exposed and extends along the flow path, and a diaphragm separating the first and second flow paths and allowing permeation of cations contained in the solution flowing through the flow path. The pair of second negative-positive electrodes is configured to be serpentine by exposing the second positive electrode to the first flow path via a first spacer member and the second negative electrode to the second flow path via a second spacer member. Hypochlorous acid water supplied from the hypochlorous acid water generation unit is configured to flow in the same direction through both the first and second flow paths. With this configuration, hypochlorous acid water generated by electrolyzing salt water flows across the diaphragm while a voltage is applied in the same direction, thereby separating and reducing cations that cause residual components from the hypochlorous acid water. This makes it possible to create a hypochlorous acid water treatment unit that can produce hypochlorous acid water with reduced residual components that result from the electrolysis of salt water.

The hypochlorous acid water supply device according to the present invention further comprises a planar second anode, a planar diaphragm facing the second anode, and a first spacer member disposed between the second anode and the diaphragm and exposing the second anode and the diaphragm within a first flow path along the flow path, the first flow path being comprised of the second anode and the diaphragm exposed along the flow path, and the first spacer member. The device also comprises a planar second negative electrode, a planar diaphragm facing the second negative electrode, and a second spacer member disposed between the second negative electrode and the diaphragm and exposing the second negative electrode and the diaphragm within a second flow path along the flow path, the second flow path being comprised of the second negative electrode and the diaphragm exposed along the flow path, and the second spacer member. This configuration allows the ability to separate cations that cause residual components from hypochlorous acid water produced by electrolyzing salt water to be varied by changing the flow path shape formed in the first spacer member and the flow path shape formed in the second spacer member, thereby enabling the area and time for separating cations that cause residual components from hypochlorous acid water to be freely designed.

The hypochlorous acid water supply device according to the present invention also includes a supply pump provided in a flow path connecting the hypochlorous acid water generation unit and the hypochlorous acid water treatment unit, which supplies hypochlorous acid water from the hypochlorous acid water generation unit to the diaphragm-equipped electrolysis flow path. The supply pump preferably supplies hypochlorous acid water from the hypochlorous acid water generation unit to the first flow path and the second flow path at a constant flow rate. This allows the time during which voltage is applied to the first flow path to be constant, and also the time during which voltage is applied to the second flow path to be constant. This makes it possible to stabilize the concentration at which cations that cause residual components in hypochlorous acid water are separated and diluted in the first flow path, and the concentration at which cations that cause residual components in hypochlorous acid water are concentrated in the second flow path.

The space sterilization system of the present invention is configured to include the hypochlorous acid water supply device described above and a sterilization device that is connected in communication with the first flow path and that uses the hypochlorous acid water discharged from the first flow path to release a hypochlorous acid water mist into a specified space. With this configuration, even when the hypochlorous acid water mist discharged from the first flow path is released into a specified space, residual components remaining in the specified space are suppressed. In other words, because the hypochlorous acid water discharged from the first flow path is hypochlorous acid water with reduced residual components generated by the electrolysis of salt water, when sterilizing a specified space, it is possible to suppress the occurrence of metal corrosion caused by residual components while maintaining sterilization performance.

In addition, the spatial sterilization system of the present invention is configured so that a drain pipe is provided in the specified space to discharge water generated within the specified space, and the second flow path is connected in communication with the drain pipe so that hypochlorous acid water discharged from the second flow path can be introduced into the drain pipe. In this way, hypochlorous acid water with high cleaning properties, including an alkaline solution in which cations that cause residual components are concentrated, is circulated from the hypochlorous acid water discharged from the second flow path into the drain pipe, allowing the drain pipe to be cleaned with the alkaline solution.

(Embodiment 1)
A hypochlorous acid water supply device 1 according to a first embodiment of the present invention will be described with reference to Fig. 1. Fig. 1 is a cross-sectional image diagram of the hypochlorous acid water supply device 1 according to the first embodiment of the present invention.

The hypochlorous acid water supply device 1 is a device that supplies salt water (aqueous sodium chloride solution) and generates hypochlorous acid water by electrolysis, and further separates and reduces residual components (components having cations such as Na ⁺ ions: e.g., NaClO, NaOH) contained in the generated hypochlorous acid water from the hypochlorous acid water flowing inside, and extracts and supplies the resulting hypochlorous acid water in a single pass.

Specifically, as shown in FIG. 1, the hypochlorous acid water supply device 1 includes a hypochlorous acid water generation unit 2 that electrolyzes salt water to generate hypochlorous acid water in a single pass, a hypochlorous acid water treatment unit 3 that separates and reduces residual components contained in the hypochlorous acid water in a single pass, and an anode-side supply pump 29 and a cathode-side supply pump 31 that circulate salt water through the flow path of the hypochlorous acid water generation unit 2 and circulate hypochlorous acid water through the flow path of the hypochlorous acid water treatment unit 3.

<Hypochlorous acid water generation unit>
The hypochlorous acid water generation unit 2 constituting the hypochlorous acid water supply device 1 will be described with reference to Figures 1 to 5. Figure 2 is a schematic diagram of the hypochlorous acid water generation unit 2. Figure 3 is an exploded perspective view of the hypochlorous acid water generation unit 2. Figure 4 is a vertical cross-sectional image of the hypochlorous acid water generation unit 2. Figure 5 is a horizontal cross-sectional image of the hypochlorous acid water generation unit 2.

As shown in Figures 2 to 5, the hypochlorous acid water generation unit 2 includes a first anode 4, a first cathode 5, a first cathode-and-anodode spacer 6, a first anode gasket 7a, a first cathode gasket 7b, a first anode-side tank housing side surface 8a, a first cathode-and-anodode side tank housing side surface 8b, a first cathode-and-anodode solution supply port 9, a first anode solution extraction port 10, a first cathode solution extraction port 11, a first cathode-and-anodode flow path 12, and an electrolysis power supply 13.

The first anode 4 is a planar electrode plate. The surface of the first anode 4 is exposed along the first inter-negative electrode flow path 12 by the first inter-negative electrode spacer 6. The first anode 4 is an electrode that functions as an anode when current is passed through it by the electrolysis power supply 13. The first anode 4 is positioned facing and approximately parallel to the first cathode 5. The first anode 4 uses a material that has a platinum-containing catalyst formed on the surface of a titanium substrate and is highly efficient at generating hypochlorous acid through electrolysis. The platinum-containing catalyst is formed on at least the surface of the first anode 4 that is exposed along the first inter-negative electrode flow path 12. NaCl in saltwater can be electrolyzed to produce hypochlorous acid water containing NaClO, HClO, and NaOH.

The first negative electrode 5 is a planar electrode plate. The surface of the first negative electrode 5 is exposed along the first negative-positive electrode flow path 12 by the first negative-positive electrode spacer 6. The first negative electrode 5 functions as a cathode when current is passed through it by the electrolysis power supply 13. The first negative electrode 5 is disposed substantially parallel to and facing the first positive electrode 4. Like the first positive electrode 4, the first negative electrode 5 has a platinum-containing catalyst formed on its surface. The platinum-containing catalyst is formed on at least the surface of the first negative electrode 5 exposed along the first negative-positive electrode flow path 12. Furthermore, the first positive electrode 4 and the first negative electrode 5 in the region exposed along the first negative-positive electrode flow path 12 where electrolysis is performed have the same shape. A shorter facing distance facilitates ion migration and electrolysis. A shorter facing distance reduces the flow rate through the flow path and reduces the amount of hypochlorous acid water that can be produced. Therefore, it is desirable to shorten the facing distance to approximately 10 mm or less while ensuring the required amount of hypochlorous acid water produced.

The first anode 4 and the first cathode 5 form a pair of opposing electrodes, forming a first cathode-and-yang electrode.

The first cathode-and-anodide spacer 6 is an insulating member. The first cathode-and-anodide spacer 6 controls the distance between the first anode 4 and the first cathode 5 to a predetermined distance. The first cathode-and-anodide spacer 6 has a first cathode-and-anodide interelectrode flow path hole 12a therein, which forms the first cathode-and-anodide interelectrode flow path 12 (described below). The first cathode-and-anodide interelectrode flow path hole 12a penetrates the first cathode-and-anodide interelectrode spacer 6 from front to back and is formed in a serpentine shape, moving back and forth horizontally and ascending step by step. A gasket member (not shown) of the same serpentine shape as the first cathode-and-anodide interelectrode spacer 6 is attached to the surface of the first cathode-and-anodide interelectrode spacer 6 to improve adhesion between the first anode 4 and the first cathode 5. The first cathode-and-anodide interelectrode spacer 6 corresponds to the "spacer member" in the claims.

The first anode gasket 7a has a shape where the size of the electrode is hollowed out on the outer periphery of the first anode 4. It is attached by applying tightening pressure to the first cathode-and-anodode spacer 6 in close contact with the circumferential direction to prevent leakage of the solution (first cathode-and-anodode supply solution 9a described below) in the first cathode-and-anodode flow path 12. Insulating silicone rubber can be used as the material for the first anode gasket 7a. The first anode gasket 7a is thicker than the first anode 4, and is preferably held in place by the thickness of the first anode 4 while being crushed by the tightening pressure to tightly contact the first cathode-and-anodode spacer 6 and the side surface of the first anode-side tank casing 8a.

The first cathode gasket 7b has a shape that is hollowed out to the size of the electrode on the outer periphery of the first cathode 5, and is attached by applying tightening pressure in a manner that makes it intimately contact with the first cathode-and-anodode spacer 6 and circumferentially prevents leakage of the solution (first cathode-and-anodode supply solution 9a, described below) in the first cathode-and-anodode flow path 12. The first cathode gasket 7b is thicker than the first cathode 5, and is preferably held in place by the thickness of the first cathode 5 while being crushed by the tightening pressure and in close contact with the first cathode-and-anodode spacer 6 and the first cathode-side cell casing side surface 8b.

The first anode side cell casing side surface 8a is positioned so as to be in direct contact with the outside of the first anode 4. To prevent the solution from seeping into the outside of the first anode 4, a gasket (not shown) is attached to the inner surface of the first anode side cell casing side surface 8a to improve adhesion, and it is desirable to apply tightening pressure to prevent the solution from seeping around to the outside of the electrode. Even if the solution does get around to the outside of the electrode, it will not leak to the outside. Because a platinum-containing catalyst is formed only on the inner surface of the first anode 4, preventing the solution from seeping around to the outside of the electrode will also lead to improved electrolysis efficiency.

The first cathode side cell casing side surface 8b is positioned so as to be in direct contact with the outside of the first cathode 5. To prevent the solution from seeping into the outside of the first cathode 5, a gasket (not shown) is attached to the inner surface of the first cathode side cell casing side surface 8b to improve adhesion, and it is desirable to apply tightening pressure to prevent the solution from seeping around to the outside of the electrode. Even if the solution does get around to the outside of the electrode, it will not leak to the outside. Because a platinum-containing catalyst is formed only on the inner surface of the first cathode 5, preventing the solution from seeping around to the outside of the electrode will also lead to improved electrolysis efficiency.

The first cathode-and-anodode solution supply port 9 is a connection port for flowing brine to be electrolyzed into the first cathode-and-anodode flow path 12, and is equipped with a connector (not shown) for connecting a tube. To supply brine from outside the first anode 45, the first cathode-and-anodode solution supply port 9 is machined at a position on the outer periphery of the first anode 4. The first cathode-and-anodode solution supply port 9 may be machined at a position on the outer periphery of the first cathode 5, or may be machined at a position on the outer side of both the first anode 4 and the first cathode 5.

The first cathode/anodizing electrode supply solution 9a is salt water. The first cathode/anodizing electrode supply solution 9a is introduced into the first cathode/anodizing electrode flow path 12 from the first cathode/anodizing electrode solution supply port 9.

The first anode solution extraction port 10 is a connection port for extracting the electrolyzed first anode extraction solution 10a from the flow path, and is equipped with a connector (not shown) for connecting a tube, leading to the anode side connection tube 28 and the anode side supply pump 29. In order to extract the first anode extraction solution 10a outside the first anode 4, the first anode solution extraction port 10 is machined at a position on the outer periphery of the first anode 4.

The first anode extraction solution 10a is hypochlorous acid water electrolyzed from salt water. The first anode extraction solution 10a is introduced into the first anode solution extraction port 10 from the first inter-negative-positive electrode flow path 12.

More specifically, the first anode extraction solution 10a contains NaClO and HClO, which are components of hypochlorous acid water, produced by electrolyzing saltwater. Other components include NaOH produced by electrolysis, NaCl produced by decomposition of NaClO, and NaCl remaining in saltwater after incomplete electrolysis. As the saltwater electrolysis progresses, the concentration of NaCl decreases, while the concentrations of NaClO, HClO, and NaOH increase. Since HClO and NaOH react to form NaClO, sufficient electrolysis of saltwater produces hypochlorous acid water containing NaClO. Components containing the positive ion Na ⁺ ion remain after evaporation, and NaClO, NaOH, and NaCl are examples of residual components produced by the electrolysis of saltwater.

The first cathode solution extraction port 11 is a connection port for extracting the electrolyzed first cathode extraction solution 11a from the flow path. It is equipped with a connector (not shown) for connecting a tube and is connected to the cathode side connection tube 30 and the cathode side supply pump 31. In order to extract the first cathode extraction solution 11a outside the first cathode 5, the first cathode solution extraction port 11 is machined at a position on the outer periphery of the first cathode 5.

The first negative electrode extraction solution 11a is hypochlorous acid water electrolyzed from salt water. The first negative electrode extraction solution 11a is introduced into the first negative electrode solution extraction port 11 from the first negative-positive electrode flow path 12.

More specifically, the first anode-cathode extraction solution 11a contains NaClO and HClO, which are components of hypochlorous acid water, produced by electrolyzing saltwater. Other components include NaOH produced by electrolysis, NaCl produced by decomposition of NaClO, and NaCl remaining in saltwater after incomplete electrolysis. As the saltwater electrolysis progresses, the concentration of NaCl decreases, while the concentrations of NaClO, HClO, and NaOH increase. Because HClO reacts with NaOH to produce NaClO, sufficient electrolysis of saltwater produces hypochlorous acid water containing NaClO. Components containing the positive ion Na ⁺ ion remain after evaporation, and NaClO, NaOH, and NaCl are examples of residual components produced by the electrolysis of saltwater.

Within the first negative-positive electrode flow path 12, the electrolyzed hypochlorous acid water is mixed during the flow process, but flows with a concentration gradient such that ^Cl- ions, which are anion components of brine, are abundant near the first positive electrode 4, and Na ⁺ ions, which are cation components of brine, are abundant near the first negative electrode 5. Therefore, when electrolysis is performed between the first negative-positive electrode, a solution that is more acidic flows near the first positive electrode 4, and a solution that is more alkaline flows near the first negative electrode. The first positive electrode solution extraction port 10 and the first negative electrode solution extraction port 11 are located on the outer periphery of the first positive electrode 4 and the first negative electrode 5, respectively, and therefore are not subject to voltage application. However, because the first positive electrode solution extraction port 10 and the first negative electrode solution extraction port 11 are designed near the first positive electrode 4 and the first negative electrode 5, acidic and alkaline hypochlorous acid waters are extracted, respectively. Specifically, acidic hypochlorous acid water containing a large amount of HCl and HClO is extracted as a first anode extraction solution 10a from a first anode solution extraction port 10 provided on the first anode 4 side, and alkaline hypochlorous acid water containing a large amount of NaOH is extracted as a first cathode extraction solution 11a from a first cathode solution extraction port 11 provided on the first cathode 5 side.

Here, it is desirable that the first cathode/anodide electrode solution supply port 9 be positioned vertically downward, and that the first anode solution extraction port 10 and the first cathode solution extraction port 11 be positioned vertically upward. When oxygen gas, hydrogen gas, etc. are generated by the electrolysis reaction in the flow path, positioning each extraction port at an upper position allows the gas to be more efficiently discharged along with the solution.

The first cathode-and-anodode flow path 12 is a flow path formed in an area surrounded by the first anode 4, the first cathode-and-anodode spacer 6, and the first cathode 5, and is a so-called membraneless electrolysis flow path. The first cathode-and-anodode flow path 12 is configured to meander due to the first cathode-and-anodode flow path holes 12a in the first cathode-and-anodode spacer 6. More specifically, the first cathode-and-anodode flow path 12 moves back and forth horizontally, and the number of horizontal movements it makes before the solution reaches the top determines the distance over which electrolysis is performed. Furthermore, by reducing the flow path width of the first cathode-and-anodode flow path 12, the distance can be increased, thereby extending the electrolysis time. To reduce backflow of the solution in the first cathode-and-anodode flow path 12, it is desirable for the first cathode-and-anodode flow path 12 to be configured so that it flows in only one direction, from bottom to top, except for the horizontal movement. The first cathode-and-anodode flow path 12 has a first cathode solution supply port 9 on one side and a first anode solution extraction port 10 and a first cathode solution extraction port 11 on the other side, through which the first cathode supply solution 9a flows. The amount of electrolysis is controlled by the applied voltage and current and the flow rate within the flow path. The flow rate can be controlled by installing an anode side supply pump 29 downstream of the first anode solution extraction port 10 and a cathode side supply pump 31 downstream of the first cathode solution extraction port 11. Each supply pump is preferably capable of controlling a constant flow rate; for example, a tube pump can be used. By flowing the solution at a constant flow rate, the electrolysis time within the flow path can be controlled to a constant value, allowing for stable control of the concentration of the extracted hypochlorous acid water.

The electrolysis power supply 13 is connected to the first anode 4 and the first cathode 5 and is a DC power supply capable of applying current and voltage to the first anode 4 and the first cathode 5. The electrolysis power supply 13 may be used as a constant current controlled power supply to maintain a constant current, or as a constant voltage controlled power supply to maintain a constant voltage. To reduce scale buildup, the electrolysis power supply 13 may be controlled to reverse the polarity by swapping the potentials of the first anode 4 and the first cathode 5 each time salt water is passed through the hypochlorous acid water generation unit 2, thereby dissolving the deposited scale.

As described above, the hypochlorous acid water generation unit 2 is composed of the following components.

<Hypochlorous acid water supply unit>
Next, the hypochlorous acid water supply unit 3 constituting the hypochlorous acid water supply device 1 will be described with reference to Fig. 1 and Fig. 6 to Fig. 9. Fig. 6 is a schematic diagram of the hypochlorous acid water treatment unit 3. Fig. 7 is an exploded perspective view of the hypochlorous acid water treatment unit 3. Fig. 8 is a vertical cross-sectional image diagram of the hypochlorous acid water treatment unit 3. Fig. 9 is a horizontal cross-sectional image diagram of the hypochlorous acid water treatment unit 3.

As shown in Figures 6 to 9, the hypochlorous acid water treatment unit 3 includes a second anode 14, a second cathode 15, a diaphragm 16, a second anode side spacer 17, a second cathode side spacer 18, a second anode gasket 19a, a second cathode gasket 19b, a second anode side tank housing side surface 20a, a second cathode side tank housing side surface 20b, a second anode solution supply port 21, a second anode solution extraction port 22, a second cathode solution supply port 23, a second cathode solution extraction port 24, a second anode side flow path 25, a second cathode side flow path 26, and an electrodialysis power supply 27.

The second anode 14 is a planar electrode plate. The second anode 14 has its surface exposed along the second anode side flow path 25 by the second anode side spacer 17. The second anode 14 functions as an anode when current is passed through it by the electrodialysis power supply 27. The second anode 14 is disposed substantially parallel to and facing the second cathode 15. The second anode 14 is made of a titanium substrate having a platinum-containing catalyst formed on its surface, and is made of a material that efficiently generates hypochlorous acid through electrolysis. The platinum-containing catalyst is formed on at least the surface of the second anode 14 that is exposed along the second anode side flow path 25. The primary purpose of electrodialysis is to migrate cations and produce hypochlorous acid water that suppresses the residual components NaClO and NaOH. However, NaCl produced by decomposition of NaClO and NaCl remaining in brine that was not completely electrolyzed can also be converted to hypochlorous acid by the platinum electrode.

The second negative electrode 15 is a planar electrode plate. The surface of the second negative electrode 15 is exposed along the flow path of the second negative electrode side flow path 26 by the second negative electrode side spacer 18. The second negative electrode 15 functions as a cathode when current is passed through it by the electrodialysis power supply 27. The second negative electrode 15 is disposed approximately parallel to and facing the second anode 14. Like the second anode 14, the second negative electrode 15 has a platinum-containing catalyst formed on its surface. The platinum-containing catalyst is formed on at least the surface of the second negative electrode 15 exposed along the flow path of the second negative electrode side flow path 26. Furthermore, the second anode 14 and second negative electrode 15 in the areas exposed along the second anode side flow path 25 and the second negative electrode side flow path 26 where electrodialysis is performed have the same shape, and a shorter facing distance facilitates ion migration. A shorter facing distance reduces the flow rate through the flow path and the amount of hypochlorous acid water that can be produced. Therefore, it is desirable to shorten the facing distance to approximately 10 mm or less while ensuring the required amount of hypochlorous acid water produced.

The second anode 14 and the second cathode 15 form a pair of opposing electrodes, forming a second cathode-and-cathode electrode.

The diaphragm 16 is a planar thin film. The diaphragm 16 is disposed substantially parallel to and facing the second anode 14 and the second cathode 15. The diaphragm 16 is disposed to separate the second anode-side flow path 25 from the second cathode-side flow path 26. The diaphragm 16 is an ion exchange membrane (cation exchange membrane) capable of transferring cations such as Na ⁺ ions related to NaClO and NaOH, which are residual components of hypochlorous acid water. The diaphragm 16 can transfer cations to the second cathode 15 by applying a voltage to the second anode 14 and the second cathode 15. Examples of this cation exchange membrane include Nafion manufactured by DuPont. Note that because the second cathode 15 side concentrates cations, scale components contained in tap water, etc., may precipitate during prolonged use. To reduce scale buildup, for example, the potentials of the second anode 14 and the second cathode 15 are reversed and polarity is inverted to dissolve the deposited scale each time hypochlorous acid water is passed through the hypochlorous acid water treatment unit 3. When it is assumed that the electrodes will be used with polarity inversion, it is desirable that the second anode 14 and the second cathode 15 be similarly treated with a catalyst containing platinum.

The second anode side spacer 17 is an insulating member. The second anode side spacer 17 controls the distance between the second anode 14 and the diaphragm 16 to a predetermined distance. The second anode side spacer 17 has second anode side flow passage holes 25a therein, which form the second anode side flow passage 25 (described later). The second anode side flow passage holes 25a are holes formed in the second anode side spacer 17 that form the second anode side flow passage 25. The second anode side flow passage holes 25a penetrate the second anode side spacer 17 from front to back and are formed in a serpentine shape, moving back and forth horizontally and ascending step by step. In addition, a packing member (not shown) of the same serpentine shape as the second anode side spacer 17 is attached to the surface of the second anode side spacer 17 to improve adhesion between the second anode 14 and the diaphragm 16. The second anode side spacer 17 corresponds to the "first spacer member" in the claims.

The second negative electrode side spacer 18 is an insulating member. The second negative electrode side spacer 18 controls the distance between the second negative electrode 15 and the diaphragm 16. The second negative electrode side spacer 18 has second negative electrode side flow path holes 26a therein, which form the second negative electrode side flow path 26 (described later). The second negative electrode side flow path holes 26a are holes that form the second negative electrode side flow path 26 formed in the second negative electrode side spacer 18. The second negative electrode side flow path holes 26a penetrate the front and back of the second negative electrode side spacer 18 and are formed in a serpentine shape, moving back and forth horizontally and ascending step by step. The second negative electrode side flow path holes 26a and the second positive electrode side flow path holes 25a are arranged opposite each other. In addition, a gasket member (not shown) having the same serpentine shape as the second negative electrode side spacer 18 is attached to the surface of the second negative electrode side spacer 18 to improve adhesion between the second negative electrode 15 and the diaphragm 16. The second negative electrode side spacer 18 corresponds to the "second spacer member" in the claims.

The second anode gasket 19a has a shape where the size of the electrode is hollowed out on the outer periphery of the second anode 14. It is attached by applying tightening pressure so that it adheres tightly to the second anode side spacer 17 and moves outward to prevent leakage of the solution in the second anode side flow path 25 (second anode supply solution 21a, described below). Insulating silicone rubber can be used as the material for the second anode gasket 19a. The second anode gasket 19a is thicker than the second anode 14, and is preferably held in place by the thickness of the second anode 14 while being crushed by the tightening pressure to adhere tightly to the second anode side spacer 17 and the second anode side tank housing side surface 20a.

The second cathode gasket 19b has a shape where the size of the electrode is hollowed out on the outer periphery of the second cathode 15. It is attached by applying tightening pressure so that it adheres closely to the second cathode side spacer 18 and prevents leakage of the solution (second cathode supply solution 23a described below) in the second cathode side flow path 26 in the circumferential direction. Insulating silicone rubber can be used as the material for the second cathode gasket 19b. The second cathode gasket 19b is thicker than the second cathode 15, and is preferably held in place by the thickness of the second cathode 15 while being crushed by the tightening pressure and adhering closely to the second cathode side spacer 18 and the second cathode side tank housing side surface 20b.

The second anode side tank housing side surface 20a is positioned so as to be in direct contact with the outside of the second anode 14. To prevent the solution from seeping into the outside of the second anode 14, a gasket (not shown) is attached to the inner surface of the second anode side tank housing side surface 20a to improve adhesion, and it is desirable to apply tightening pressure to prevent the solution from leaking outside the electrode. Even if the solution does get around the outside of the electrode, it will not leak to the outside. Because a platinum-containing catalyst is formed only on the inner surface of the second anode 14, preventing the solution from getting around to the outside of the electrode will also lead to improved electrodialysis efficiency.

The second cathode side tank housing side surface 20b is positioned so as to be in direct contact with the outside of the second cathode 15. To prevent the solution from seeping into the outside of the second cathode 15, a gasket (not shown) is attached to the inner surface of the second cathode side tank housing side surface 20b to improve adhesion, and it is desirable to apply tightening pressure to prevent the solution from leaking outside the electrode. Even if the solution does get around the outside of the electrode, it will not leak to the outside. Because a platinum-containing catalyst is formed only on the inner surface of the second cathode 15, preventing the solution from getting around to the outside of the electrode will also lead to improved efficiency of electrode dialysis.

The second anode solution supply port 21 is a connection port for flowing the second anode supply solution 21a to be electrodialyzed into the flow path, and is equipped with a connector (not shown) for connecting a tube. To supply the second anode supply solution 21a from outside the second anode 14, the second anode solution supply port 21 is machined at a position on the outer periphery of the second anode 14.

The second anode supply solution 21a is hypochlorous acid water electrolyzed from salt water in the hypochlorous acid water generation unit 2. More specifically, the second anode supply solution 21a is the first anode extraction solution 10a supplied from the first anode solution extraction port 10, and is acidic hypochlorous acid water containing a large amount of HCl and HClO. The second anode supply solution 21a is introduced into the second anode side flow path 25 from the second anode solution supply port 21.

The second anode solution extraction port 22 is a connection port for extracting the electrodialyzed second anode extraction solution 22a from the flow path, and is equipped with a connector (not shown) to which a tube can be connected. In order to extract the second anode extraction solution 22a outside the second anode 14, the second anode solution extraction port 22 is machined at a position on the outer periphery of the second anode 14.

The second anode extraction solution 22a is hypochlorous acid water containing HClO as its main component. The second anode extraction solution 22a is introduced into the second anode solution extraction port 22 from the second anode side flow path 25.

More specifically, the second anode extraction solution 22a is a solution obtained by separating and diluting the cations that cause residual components from the second anode supply solution 21a by passing the second anode supply solution 21a through the second anode-side flow path 25. Since the second anode supply solution 21a uses hypochlorous acid water (first anode supply solution 10a) generated by electrolyzing salt water in the hypochlorous acid water unit 2, the second anode extraction solution 22a has Na ⁺ ions, which are cations, separated and diluted, resulting in hypochlorous acid water mainly composed of HClO. The pH indicates acidity.

The second cathode solution supply port 23 is a connection port for flowing the second cathode supply solution 23a to be electrodialyzed into the flow path, and is equipped with a connector (not shown) for connecting a tube. To supply the second cathode supply solution 23a from outside the second cathode 15, the second cathode solution supply port 23 is machined at a position on the outer periphery of the second cathode 15.

The second cathode supply solution 23a is hypochlorous acid water electrolyzed from salt water in the hypochlorous acid water generation unit 2. More specifically, the second cathode supply solution 23a is the first cathode extraction solution 11a supplied from the first cathode solution extraction port 11, and is alkaline hypochlorous acid water containing a large amount of NaOH. The second cathode supply solution 23a is introduced into the second cathode side flow path 26 from the second cathode solution supply port 23.

The second cathode solution extraction port 24 is a connection port for extracting the electrodialyzed second cathode extraction solution 24a from the flow path, and is equipped with a connector (not shown) to which a tube can be connected. In order to extract the second cathode extraction solution 24a outside the second cathode 15, the second cathode solution extraction port 24 is machined at a position on the outer periphery of the second cathode 15.

The second negative electrode extraction solution 24a is hypochlorous acid water containing NaClO and NaOH as its main components. The second negative electrode extraction solution 24a is discharged from the second negative electrode side flow path 26 to the second negative electrode solution extraction port 24.

More specifically, the second cathode extraction solution 24a is a solution in which cations that cause residual components are concentrated by passing the second cathode supply solution 23a through the second cathode side flow path 26. Since the second cathode supply solution 23a uses hypochlorous acid water (first cathode supply solution 11a) generated by electrolyzing salt water in the hypochlorous acid water unit 2, the second cathode extraction solution 24a has Na ⁺ ions, which are cations, separated and concentrated to form NaOH, resulting in hypochlorous acid water primarily composed of NaOH and NaClO. The pH indicates alkalinity.

Here, the second anode solution supply port 21 and the second cathode solution supply port 23 are preferably positioned vertically downward, and the second anode solution extraction port 22 and the second cathode solution extraction port 24 are preferably positioned vertically upward. When oxygen gas, hydrogen gas, etc. are generated by the electrodialysis reaction and electrolysis reaction in the flow path, positioning the extraction ports at the top allows the gas to be more efficiently discharged together with the solution.

The second anode side flow path 25 is a flow path formed in the area surrounded by the second anode 14, the second anode side spacer 17, and the diaphragm 16. The second anode side flow path 25 is configured to meander via the second anode side flow path holes 25a in the second anode side spacer 17. More specifically, the second anode side flow path 25 moves back and forth horizontally, and the number of horizontal reciprocations increases the distance over which electrodialysis is performed until the anode side solution reaches the top. Furthermore, narrowing the flow path width of the second anode side flow path 25 increases the distance, thereby extending the electrodialysis time. To reduce backflow of solution in the second anode side flow path 25, it is desirable for the second anode side flow path 25 to be configured so that it flows in one direction, from bottom to top, except for its horizontal reciprocation. The second anode side flow path 25 has a second anode solution supply port 21 on one side and a second anode solution extraction port 22 on the other side, through which the second anode supply solution 21a, which is the anode side solution, flows. The second anode side flow path 25 corresponds to the "first flow path" in the claims.

The second cathode side flow path 26 is a flow path formed in the area surrounded by the second cathode 15, the second cathode side spacer 18, and the diaphragm 16. The second cathode side flow path 26 is configured to meander via the second cathode side flow path holes 26a in the second cathode side spacer 18. More specifically, the second cathode side flow path 26 moves back and forth horizontally, and the number of horizontal reciprocations increases the distance over which electrodialysis is performed until the cathode side solution reaches the top. Furthermore, narrowing the flow path width of the second cathode side flow path 26 increases the distance, thereby extending the electrodialysis time. To reduce backflow of liquid in the second cathode side flow path 26, it is desirable to design the second cathode side flow path 26 so that the flow direction is unidirectional, from bottom to top, except for the horizontal reciprocation. The second cathode side flow path 26 has a second cathode solution supply port 23 on one side and a second cathode solution extraction port 24 on the other side, through which the second cathode supply solution 23a, which is the cathode side solution, flows. The second negative electrode side flow path 26 corresponds to the "second flow path" in the claims.

The second anode side flow path 25 and the second cathode side flow path 26 are symmetrically opposed to each other with the diaphragm 16 interposed therebetween. That is, the second anode side flow path 25 and the second cathode side flow path 26 are configured in a serpentine shape, facing each other with the diaphragm 16 interposed therebetween. In this manner, the second anode side flow path 25 and the second cathode side flow path 26 constitute a so-called diaphragm-equipped electrolysis flow path. ^Na ions contained in the hypochlorous acid water flowing through the second anode side flow path 25 migrate to the second cathode side flow path 26. The amount of ion migration is controlled by the applied voltage/current and the flow rate within the flow path. The flow rate can be controlled by installing an anode side supply pump 29 upstream of the second anode solution supply port 21 and a cathode side supply pump 31 upstream of the second cathode solution supply port 23. Each pump is preferably capable of controlling a constant flow rate; for example, a tube pump can be used. By flowing the solution at a constant flow rate, the time for electrodialysis and electrolysis within the flow path can be controlled at a constant level, allowing for stable control of the concentration of the extracted hypochlorous acid water.

The electrodialysis power supply 27 is connected to the second anode 14 and the second cathode 15 and is a DC power supply capable of applying current and voltage to the second anode 14 and the second cathode 15. The electrodialysis power supply 27 may be used as a constant current controlled power supply to provide a constant current, or as a constant voltage controlled power supply to provide a constant voltage. To reduce scale buildup, the electrodialysis power supply 27 may be controlled, for example, to reverse the potentials of the second anode 14 and the second cathode 15 each time hypochlorous acid water is passed through the hypochlorous acid water treatment unit 3, thereby dissolving the deposited scale.

As shown in FIG. 1, the anode side connection tube 28 is a tube that connects the first anode solution extraction port 10 of the hypochlorous acid water generation unit 2 to the second anode solution supply port 21 of the hypochlorous acid water treatment unit 3 via the anode side supply pump 29. When the anode side supply pump 29 operates, the anode side connection tube 28 delivers the hypochlorous acid water (first anode extraction solution 10a) generated in the hypochlorous acid water generation unit 2 to the second anode solution supply port 21 of the hypochlorous acid water treatment unit 3. The anode side connection tube 28 can be made of, for example, a silicone tube.

The cathode side connection tube 30 connects the first cathode solution extraction port 11 of the hypochlorous acid water generation unit 2 to the second cathode solution supply port 23 of the hypochlorous acid water treatment unit 3 via the cathode side supply pump 31. The cathode side connection tube 30 delivers the hypochlorous acid water (first cathode extraction solution 11a) generated in the hypochlorous acid water generation unit 2 to the second cathode solution supply port 23 of the hypochlorous acid water treatment unit 3. The cathode side connection tube 30 can be made of, for example, a silicone tube.

The anode side connection tube 28 and the cathode side connection tube 30 have, for example, the same inner diameter and the same length, so that there is no difference in the flow rate and flow velocity of the solution flowing inside.

The anode side supply pump 29 generates a flow of the first anode extraction solution 10a generated in the hypochlorous acid water generation unit 2, supplying it as the second anode supply solution 21a. More specifically, the anode side supply pump 29 generates a flow of each solution (brine, first anode supply solution 9a, first anode extraction solution 10a, second anode supply solution 21a, and second anode extraction solution 22a) that flows sequentially through the first anode/node solution supply port 9, first inter-anode flow path 12, first anode solution extraction port 10, second anode solution supply port 21, second anode side flow path 25, and second anode solution extraction port 22. The anode side supply pump 29 simultaneously controls the flow rate of the solutions flowing through the hypochlorous acid water generation unit 2 and simultaneously controls the flow rate of the solutions flowing through the hypochlorous acid water treatment unit 3 to a constant value. Examples of pumps capable of delivering a constant flow rate include a tube pump and a diaphragm pump.

The cathode side supply pump 31 generates a flow of the first cathode extraction solution 11a generated in the hypochlorous acid water generation unit 2, supplying it as the second cathode supply solution 23a. More specifically, the cathode side supply pump 31 generates a flow of each solution (brine, first cathode/anodide supply solution 9a, first cathode extraction solution 11a, second cathode supply solution 22a, and second cathode extraction solution 24a) that flows sequentially through the first cathode/anodide electrode solution supply port 9, the first cathode/anodide flow path 12, the first cathode solution extraction port 11, the second cathode solution supply port 23, the second cathode side flow path 26, and the second cathode solution extraction port 23. In this case, the cathode side supply pump 31 simultaneously controls the flow rate of the solutions flowing through the hypochlorous acid water generation unit 2 and simultaneously controls the flow rate of the solution flowing through the hypochlorous acid water treatment unit 3 to a constant value. Examples of pumps capable of delivering a constant flow rate include a tube pump and a diaphragm pump.

The flow rate of the first cathode-and-anode electrode flow path 12 is controlled as the sum of the flow rates of the anode side supply pump 29 and the cathode side supply pump 31. The anode side supply pump 29 and the cathode side supply pump 31 correspond to the "supply pumps" in the claims.

As described above, the hypochlorous acid water treatment unit 3 is composed of the following components.

As shown in FIG. 1, the hypochlorous acid water supply device 1 is configured by connecting the hypochlorous acid water generation unit 2 and the hypochlorous acid water treatment unit 3 described above via a positive electrode side connection tube 28 provided in the flow path on the positive electrode side of each unit and via a negative electrode side connection tube 30 provided in the flow path on the negative electrode side of each unit. The hypochlorous acid water supply device 1 continuously introduces saltwater into the hypochlorous acid water generation unit 2 and continuously supplies hypochlorous acid water from the hypochlorous acid water treatment unit 3 to the outside. More specifically, the hypochlorous acid water supply device 1 electrolyzes the saltwater continuously introduced into the hypochlorous acid water generation unit 2 and supplies the second anode extraction solution 22a, which is delivered from the second anode side flow path 25 on the anode side of the hypochlorous acid water treatment unit 3, to the outside as acidic hypochlorous acid water. In addition, the hypochlorous acid water supply device 1 supplies the second negative electrode extraction solution 24a delivered from the second negative electrode side flow path 26 on the negative electrode side of the hypochlorous acid water treatment unit 3 to the outside as alkaline hypochlorous acid water.

Next, the processing operation of the hypochlorous acid water generation unit 2 will be described with reference to Figures 4 and 5.

As shown in FIGS. 4 and 5 , in the hypochlorous acid water generation unit 2, a first cathode-and-anodode feed solution 9a, which is salt water, is continuously supplied to the first cathode-and-anodode flow path 12 through the first cathode-and-anodode solution supply port 9. The first cathode-and-anodode feed solution 9a supplied from the first cathode-and-anodode solution supply port 9 flows through the meandering first cathode-and-anodode flow path 12. At this time, as the first cathode-and-anodode feed solution 9a flows through the first cathode-and-anodode flow path 12, a voltage is applied to the first anode 4 and the first cathode 5 at both ends. When a voltage is applied, anions (Cl ⁻ ions) are attracted to the first anode 4 side and cations (Na ⁺ ions) are attracted to the first cathode 5 side, and HCl and HClO are produced on the first anode 4 side and NaOH is produced on the first cathode 5 side by electrolysis. Furthermore, HClO and NaOH react to produce NaClO. By repeating this process, hypochlorous acid water containing NaClO as the main component and containing HClO, NaOH, and residual NaCl is produced.

In the treatment operation of the hypochlorous acid water generation unit 2, the amount of NaCl electrolyzed can be increased by extending the time for electrolysis in the first cathode-and-anodode flow path 12, thereby reducing the amount of NaCl (brine) remaining in the first anode extraction solution 10a and the first cathode extraction solution 11a. To extend the electrolysis time, it is necessary to extend the distance of the first cathode-and-anodode flow path 12. To achieve this, the flow path is formed in a serpentine shape, moving back and forth horizontally while ascending step by step. The number of horizontal reciprocations required for the solution to reach the top increases the distance for electrolysis. Furthermore, reducing the cross-sectional area of the first cathode-and-anodode flow path 12 also increases the distance, thereby enabling the electrolysis time to be extended.

Next, the processing operation of the hypochlorous acid water processing unit 3 will be explained with reference to Figures 8 and 9.

8 and 9 , in the hypochlorous acid water treatment unit 3, a second anode feed solution 21a, which is hypochlorous acid water, is continuously supplied to the second anode side flow path 25 through the second anode solution supply port 21, and a second cathode feed solution 23a, which is hypochlorous acid water, is continuously supplied to the second cathode side flow path 26 through the second cathode solution supply port 23. The second anode feed solution 21a supplied from the second anode solution supply port 21 flows through the second anode side flow path 25, which is formed in a serpentine shape, and the second cathode feed solution 23a supplied from the second cathode solution supply port 23 flows through the second cathode side flow path 26, which is also formed in a serpentine shape. At this time, the second anode feed solution 21a and the second cathode feed solution 23a face each other across the diaphragm 16 and flow in the same direction through the second anode side flow path 25 and the second cathode side flow path 26, respectively, while a voltage is applied to the second anode 14 and the second cathode 15 at both ends. When a voltage is applied, anions are attracted to the second anode 14 side, and cations (Na ⁺ ions) are attracted to the second cathode 15 side. Because the diaphragm 16 is composed of a membrane that is permeable only to cations, cations (Na ⁺ ions) contained in the second anode supply solution 21a flowing through the second anode-side flow path 25 permeate the diaphragm 16 and pass through the second cathode supply solution 23a in the second cathode-side flow path 26, whereby the cations (Na ⁺ ions) are attracted to the second cathode 15 side. Conversely, anions flowing through the second cathode-side flow path 26 cannot permeate the diaphragm 16, and therefore only the anions contained in the second anode-side flow path 25 are attracted to the second anode 14. By repeating this process, cations (Na ⁺ ions) contained in the second anode feed solution 21a flowing through the second anode side flow path 25 migrate to the second cathode feed solution 23a flowing through the second cathode side flow path 26, and electrodialysis progresses. The cations (Na + ions) are separated and diluted from the second anode feed solution 21a flowing through the second anode side flow path 25, and the cations (Na ⁺ ions) are concentrated and extracted from the second cathode feed solution 23a flowing through the second cathode side flow path 26. As a result, hypochlorous acid water containing HClO as ^the main component and NaClO as the remaining components separated and diluted is extracted from the second anode solution extraction port 22 as the second anode extraction solution 22a. Conversely, a solution (hypochlorous acid water) containing Na ⁺ ions constituting the remaining components and a component generated as NaOH is extracted from the second cathode solution extraction port 24 as the second cathode extraction solution 24a.

In the treatment operation of the hypochlorous acid water treatment unit 3, by extending the time for electrodialysis in the second anode side flow path 25 and the second cathode side flow path 26, the amount of cation (Na ⁺ ion) movement can be increased, thereby further reducing the residual components consisting of NaClO and NaOH in the second anode extraction solution 22a. To extend the time for electrodialysis, it is necessary to increase the distance between the second anode side flow path 25 and the second cathode side flow path 26. To achieve this, the second anode side flow path 25 and the second cathode side flow path 26 are formed in a serpentine shape, moving back and forth horizontally and ascending step by step. The number of horizontal reciprocations required for the solution to reach the top increases the distance for electrodialysis. Furthermore, by reducing the cross-sectional area of the second anode side flow path 25 and the second cathode side flow path 26, the distance can be increased, thereby lengthening the electrodialysis time.

The pumps are controlled so that the flow rates of the solutions passing through the second anode side flow path 25 and the second cathode side flow path 26 are the same, but they may be different. Different flow rates affect the concentrations of the extracted solutions. For example, if the flow rate of the second anode side flow path 25 is relatively fast and the flow rate of the second cathode side flow path 26 is relatively slow, the amount of second cathode extraction solution 24a extracted from the second cathode side flow path 26 will be smaller and more concentrated than if the flow rates of the second anode side flow path 25 and the second cathode side flow path 26 were the same. Therefore, when draining the second cathode extraction solution 24a, it is desirable to slow the flow rate of the second cathode side flow path 26.

Next, referring to Figure 10, the characteristics (conductivity, pH, and effective chlorine concentration) of the hypochlorous acid water of the second anode extraction solution 22a and the second cathode extraction solution 24a actually circulated through the hypochlorous acid water supply device 1 (hypochlorous acid water generation unit 2 and hypochlorous acid water treatment unit 3) and extracted from the second anode solution extraction port 22 and the second cathode solution extraction port 24, respectively, will be described. Figure 10 is a diagram showing the relationship between the characteristics of hypochlorous acid water circulated through the hypochlorous acid water supply device 1 and electrodialysis time. More specifically, Figure 10(a) shows the relationship between electrodialysis time and conductivity in the hypochlorous acid water supply device 1. Figure 10(b) shows the relationship between electrodialysis time and pH in the hypochlorous acid water supply device 1. Figure 10(c) shows the relationship between electrodialysis time and effective chlorine concentration in the hypochlorous acid water supply device 1.

10, the hypochlorous acid water generation unit 2 was used, which had a first cathode-and-anodide flow path 12 with a flow path cross-sectional area of 26 mm ² and a flow path length of 675 mm, and the hypochlorous acid water treatment unit 3 was used, which had a second anode-side flow path 25 and a second cathode-side flow path 26 with a flow path cross-sectional area of 8 mm ² and a flow path length of 675 mm. The flow rate conditions of the anode-side supply pump 29 and the cathode-side demand pump 31 were both set at flow rates of 153 mL/h and 250 mL/h to adjust the electrolysis time of the hypochlorous acid water generation unit 2 and the electrodialysis time of the hypochlorous acid water treatment unit 3, and the conductivity, pH, and available chlorine concentration of the second anode extraction solution 22a and the second cathode extraction solution 24a were measured.

The brine 9a supplied to the first cathode/cathode solution supply port 9 had a conductivity of 405 μS/cm, a pH of 6.7, an available chlorine concentration of 0 ppm, and a chloride ion concentration of 138 ppm. Electrolysis and electrodialysis were performed using the electrolysis power supply 13 and the electrodialysis power supply 27, which were capable of applying a constant current of 0.2 A. Here, the electrolysis time refers to the time the solution is in direct contact with the first anode 4 and the first cathode 5 within the flow path; the longer the electrolysis time, the slower the flow rate. The electrodialysis time refers to the time the solution is in direct contact with the second anode 14 and the second cathode 15 within the flow path; the longer the electrodialysis time, the slower the flow rate. In this experiment, the flow rates on the anode side and the cathode side were set to be the same when electrodialysis was performed.

10(a) 的电性调节时间增加、即，流速减少时间，对于阳氧化水产生的第二阳氧化电极萃取溶液22a(氧化电极从22中的电极从12中的电极从12中的电极从25中的电极从35中的电极从45中的电极从55中的电极从55中的电极从55中的电极从55中的电极从65中的电极从65中的电极从75中的电极从75中的电极从75中的电极从95离子16移动到阳极从。 10(a) shows the conductivity of the second anode extraction solution 22a (anode side conductivity) extracted from the second anode solution extraction port 22 (anode side conductivity) increased, for the longer electrodialysis time, in other words, the slower the flow rate. This is thought to be because, when hypochlorous acid water generated in the hypochlorous acid water generation unit 2 flows through the second anode side flow path 25 of the hypochlorous acid water treatment unit 3, Na ⁺ ions, which are cations contained in the anode side solution, pass through the diaphragm 16 and move to the cathode side, converting NaClO to HClO on the anode side, resulting in a decrease in conductivity. NaClO ionizes into Na ⁺ ions and ClO ^- ions, but because HClO mainly exists as a molecule, the conversion of NaClO to HClO reduces conductivity.

The pH transition shown in Figure 10(b) shows that the pH of the second anode extraction solution 22a (pH on the anode side) changes to a weakly acidic side, while the pH of the second cathode extraction solution 24a (pH on the cathode side) changes to an alkaline side. This indicates the influence of the change to HClO on the anode side. The reason why the pH approaches neutral as the electrodialysis time on the anode side increases is thought to be because the small amount of chloride ions remaining in the solution are converted to hypochlorous acid by electrolysis. On the other hand, on the cathode side, the migration of Na ⁺ ions results in the formation of NaOH, which changes the solution to an alkaline state.

Looking at the change in effective chlorine concentration shown in Figure 10(c), the effective chlorine concentration of the second anode extraction solution 22a (effective chlorine concentration on the anode side) increases with electrodialysis time. Under the flow rate conditions shown in Figure 10(a) where the conductivity falls to 405 μS/cm or less, the rate of increase in effective chlorine concentration slows, suggesting that the conversion to HClO is nearing completion. Similarly, the effective chlorine concentration of the second cathode extraction solution 24a (effective chlorine concentration on the cathode side) increases with electrodialysis time. This is thought to be because, when the flow rates of the anode side supply pump 29 and the cathode side supply pump 31 slow, the electrolysis time in the hypochlorous acid water generation unit 2 increases, increasing the amount of hypochlorous acid water generated, which in turn increases the amount of hypochlorous acid water extracted at the second cathode extraction port 24 of the hypochlorous acid water treatment unit 3.

The hypochlorous acid water supply device 1 can simultaneously extract hypochlorous acid water primarily composed of HClO, which has high disinfecting power, from the anode side, and hypochlorous acid water primarily composed of NaClO and NaOH, which has high cleaning power, from the cathode side. HClO-based hypochlorous acid water is a solution with reduced residual components, which maintains its disinfecting power while suppressing metal corrosion caused by residual components even when sprayed into the air. Meanwhile, hypochlorous acid water primarily composed of NaClO and NaOH cannot be sprayed into the air because it leaves behind residual components, but it is a highly cleaning solution and can provide a cleaning effect when poured into areas with acidic dirt, such as drains. With the hypochlorous acid water treatment device 1, the HClO-based hypochlorous acid water generated on the anode side can be used for air disinfection, while the NaClO- and NaOH-based hypochlorous acid water generated on the opposite cathode side can also be used for cleaning.

As described above, the hypochlorous acid water supply device 1 according to the first embodiment can provide the following benefits.

(1) The hypochlorous acid water supply device 1 comprises a hypochlorous acid water generation unit 2 that continuously generates hypochlorous acid water by electrolysis by passing current between a pair of first cathode and anode electrodes (between the first anode 4 and the first cathode 5) from salt water supplied into a serpentine, membrane-less electrolysis flow path (first cathode-and-anode electrode flow path 12); and a hypochlorous acid water treatment unit 3 that continuously treats the hypochlorous acid water supplied from the hypochlorous acid water generation unit 2 into each of the serpentine, membrane-equipped electrolysis flow paths (second anode-side flow path 25 and second cathode-side flow path 26) by passing current between a pair of second cathode and anode electrodes (between the second anode 14 and the second cathode 15). The hypochlorous acid water discharged from the electrolysis flow path (second anode-side flow path 25) on the anode side of the hypochlorous acid water treatment unit 3 is supplied to the outside.

With this configuration, in the hypochlorous acid water generation unit 2, salt water is electrolyzed in the diaphragm-less electrolysis flow path (first negative-positive electrode flow path 12) to generate hypochlorous acid water, and the hypochlorous acid water generated in the diaphragm-less electrolysis flow path is then circulated through the diaphragm-containing electrolysis flow paths (second positive electrode side flow path 25 and second negative electrode side flow path 26), allowing hypochlorous acid water to be extracted from the positive electrode side with reduced amounts of cations that cause residual components. This allows for a one-pass hypochlorous acid water supply device 1 that can supply hypochlorous acid water from which residual components resulting from the electrolysis of salt water have been separated to the outside.

In addition, in the hypochlorous acid water supply device 1, by making each flow path (the diaphragm-less electrolysis flow path and the diaphragm-containing electrolysis flow path) serpentine, the path along which the salt water and hypochlorous acid water come into contact with the electrodes and diaphragms, respectively, is lengthened, making it possible to increase the distance and time required for the electrolysis of salt water and the separation of cations that cause residual components from the hypochlorous acid water. In other words, relative to the size of the electrodes, the electrolysis of salt water and the separation of cations that cause residual components from the hypochlorous acid water can be carried out efficiently.

(2) In the hypochlorous acid water supply device 1, the diaphragm-less electrolysis flow path (first cathode-and-anodode flow path 12) of the hypochlorous acid water generation unit 2 is configured to include a planar first anode 4, a planar first cathode 5 facing the first anode 4, and a first cathode-and-anodode spacer 6 provided between the first anode 5 and the first cathode 5. The pair of first cathode-and-anododes (first anode 4 and first cathode 5) is configured in a serpentine shape by exposing the first anode 4 and first cathode 5 to the diaphragm-less electrolysis flow path via the first cathode-and-anodode spacer 6. In this way, the ability to electrolyze brine can be changed by changing the flow path shape formed in the first cathode-and-anodode spacer 6, allowing the area and time for electrolyzing brine to be freely designed.

(3) In the hypochlorous acid water supply device 1, the membrane-equipped electrolysis flow paths (second anode side flow path 25 and second cathode side flow path 26) of the hypochlorous acid water treatment unit 3 include a serpentine second anode side flow path 25 in which the second anode 14 is exposed and extended along the flow path, a serpentine second cathode side flow path 26 in which the second cathode 15 is exposed and extended along the flow path, and a second anode side flow path 25 and a second cathode side flow path 26 in which the second anode side flow path 25 and the second cathode side flow path 26 are separated from each other, and allow cations contained in the solution flowing through the flow paths to pass through. and a diaphragm 16 through which the second cathode-positive electrode 14 is inserted. The pair of second cathode-positive electrodes (second anode 14 and second cathode 15) are configured in a serpentine shape by exposing the second anode 14 to the second anode-positive electrode side flow path 25 via a second anode-side spacer 17 and exposing the second cathode 15 to the second cathode-positive electrode side flow path 26 via a second cathode-positive electrode side spacer 18. Hypochlorous acid water supplied from the hypochlorous acid water generation unit 2 flows in the same direction through both the second anode-positive electrode side flow path 25 and the second cathode-positive electrode side flow path 26.

With this configuration, hypochlorous acid water produced by electrolyzing salt water flows through the diaphragm 16 while a voltage is applied in the same direction, allowing cations that cause residual components to be separated and reduced from the hypochlorous acid water. This allows the hypochlorous acid water treatment unit 3 to produce hypochlorous acid water with reduced residual components produced by the electrolysis of salt water. More specifically, the hypochlorous acid water extracted from the anode side is hypochlorous acid water in which the cations that cause residual components have been separated and diluted, while the hypochlorous acid water extracted from the cathode side is hypochlorous acid water in which the cations that cause residual components have been concentrated. In other words, hypochlorous acid water in which the cations that cause residual components have been separated and diluted can be obtained from the anode side of the hypochlorous acid water supply device 1, and highly detergency hypochlorous acid water containing an alkaline solution in which the cations that cause residual components have been concentrated can be simultaneously obtained from the cathode side of the hypochlorous acid water supply device 1.

(4) The hypochlorous acid water supply device 1 includes a planar second anode 14, a planar diaphragm 16 facing the second anode 14, and a second anode side spacer 17 disposed between the second anode 14 and the diaphragm 16 and exposing the second anode 14 and the diaphragm 16 in the second anode side flow path 25 along the flow path, the second anode side flow path being constituted by the second anode 14 and the diaphragm 16 exposed along the flow path and the second anode side spacer 17. It also includes a planar second cathode 14, a planar diaphragm 16 facing the second cathode 15, and a second cathode side spacer 18 disposed between the second cathode 15 and the diaphragm 16 and exposing the second cathode 15 and the diaphragm 16 in the second cathode side flow path 26 along the flow path, the second cathode side flow path 26 being constituted by the second cathode 15 and the diaphragm 16 exposed along the flow path and the second cathode side spacer 18. By doing this, the ability to separate cations that cause residual components from the hypochlorous acid water produced by electrolyzing salt water can be changed by changing the shape of the flow path formed in the second anode side spacer 17 and the shape of the flow path formed in the second cathode side spacer 18, so the area and time for separating cations that cause residual components from the hypochlorous acid water can be freely designed.

(5) The hypochlorous acid water supply device 1 is provided in a flow path connecting the hypochlorous acid water generation unit 2 and the hypochlorous acid water treatment unit 3, and includes supply pumps (anode side supply pump 29 and cathode side supply pump 31) that supply hypochlorous acid water from the hypochlorous acid water generation unit 2 to the diaphragm-equipped electrolysis flow paths (second anode side flow path 25 and second cathode side flow path 26). The supply pumps supply hypochlorous acid water from the hypochlorous acid water generation unit 2 to the second anode side flow path 25 and the second cathode side flow path 26 at a constant flow rate. This allows the time during which a voltage is applied to the second anode side flow path 25 to be constant, and also the time during which a voltage is applied to the second cathode side flow path 26 to be constant. This allows the concentration at which cations that cause residual components in the hypochlorous acid water are separated and diluted in the second anode side flow path 25 and the concentration at which cations that cause residual components in the hypochlorous acid water are concentrated in the second cathode side flow path 26 to be stable.

(Embodiment 2)
1 and 11, a space sterilization system 40 using a hypochlorous acid water supplying device 1 according to embodiment 2 of the present invention will be described. FIG. 11 is a schematic diagram of a space sterilization system 40 using a hypochlorous acid water supplying device 1 according to embodiment 2 of the present invention. Note that the space sterilization system 40 according to embodiment 2 described below is a system incorporating the hypochlorous acid water supplying device 1 according to embodiment 1. In the description of embodiment 2, components substantially similar to those of the hypochlorous acid water supplying device 1 according to embodiment 1 are denoted by the same reference numerals, and the description may be partially simplified or omitted.

The space sterilization system 40 according to the second embodiment is a system that sterilizes and cleans the bathroom space by spraying hypochlorous acid water generated by the hypochlorous acid water supply device 1 from the mist spray device 44 and discharging the hypochlorous acid water through the drain outlet 46. The bathroom space corresponds to the "predetermined space" in the claims.

Specifically, as shown in FIG. 11, the spatial sterilization system 40 includes a hypochlorous acid water supply device 1 (hypochlorous acid water generation unit 2, hypochlorous acid water treatment unit 3, anode side supply pump 29, and cathode side supply pump 31), anode side extraction solution tank 41, cathode side extraction solution tank 42, anode side extraction solution bathroom piping 43, mist spray device 44, cathode side extraction solution bathroom piping 45, and a drain outlet 46.

The hypochlorous acid water generation unit 2 constituting the hypochlorous acid water supply device 1 is a unit that supplies saltwater (aqueous sodium chloride solution) and generates hypochlorous acid water through electrolysis. As described above, the hypochlorous acid water generated by the hypochlorous acid water generation unit 2 contains NaClO and HClO, which are components of hypochlorous acid water. Other components include NaOH generated by electrolysis, NaCl formed by decomposition of NaClO, and NaCl remaining in saltwater due to incomplete electrolysis. More specifically, in the hypochlorous acid water generation unit 2, the anode side supply pump 29 and the cathode side supply pump 31 are operated to extract acidic hypochlorous acid water rich in HCl and HClO as the first anode extraction solution 10a from the first anode solution extraction port 10 provided on the first anode 4 side, and alkaline hypochlorous acid water rich in NaOH as the first cathode extraction solution 11a from the first cathode solution extraction port 11 provided on the first cathode 5 side.

The hypochlorous acid water treatment unit 3 circulates hypochlorous acid water supplied from the hypochlorous acid water generation unit 2, extracting a second anode extraction solution 22a, which is hypochlorous acid water mainly composed of HClO and has high disinfecting power, from the second anode side flow path 25, and extracting a second cathode extraction solution 24a, which is hypochlorous acid water mainly composed of NaClO and NaOH and has high detergency, from the second cathode side flow path 26. The second anode extraction solution 22a is stored in the anode side extraction solution tank 41 and then sent to the mist sprayer 44 via the anode side extraction solution bathroom piping 43. The second anode extraction solution 22a is then sprayed from the mist sprayer 44 into the bathroom space. The second cathode extraction solution 24a is stored in the cathode side extraction solution tank 42 and then sent to the drain 46 via the cathode side extraction solution bathroom piping 45. The second cathode extraction solution 24a flows through the drain outlet 46 and flows into the drain pipe via the drain outlet 46.

The positive electrode side extraction solution tank 41 is a tank that temporarily stores the second positive electrode extraction solution 22a, which is hypochlorous acid water mainly composed of HClO and has high disinfecting power, extracted from the second positive electrode side flow path 25 until it is sent to the mist spray device 44. The positive electrode side extraction solution tank 41 is connected to the mist spray device 44 via the positive electrode side extraction solution bathroom piping 43.

The cathode side extraction solution tank 42 is a tank that temporarily stores the second cathode extraction solution 24a, which is hypochlorous acid water mainly composed of NaClO and NaOH and has high detergency, extracted from the second cathode side flow path 26 until it is sent to the drain outlet 46. The cathode side extraction solution tank 42 is connected to the drain outlet 46 via the cathode side extraction solution bathroom piping 45.

The positive electrode side extraction solution bathroom piping 43 is a piping for transporting the solution from the positive electrode side extraction solution tank 41 to the mist spray device 44. It is installed behind the bathroom wall and on the ceiling, and is connected to the mist spray device 44 installed on the ceiling.

The negative electrode side extraction solution bathroom piping 45 is a piping for transporting the solution from the negative electrode side extraction solution tank 42 to the drain outlet 46. It is installed on the back of the bathroom wall and floor and is connected to the drain outlet 46.

The mist sprayer 44 is a device that sprays hypochlorous acid water into a mist into the bathroom space. More specifically, the mist sprayer 44 is a device that converts the second anode extraction solution 22a, which is hypochlorous acid water transported from the anode side extraction solution tank 41 through the anode side extraction solution bathroom piping 43, into a fine mist and releases it. The mist sprayer 44 is installed with its spray section protruding from the ceiling toward the bathroom side so that mist can be sprayed from the ceiling of the bathroom space throughout the entire bathroom space. Mist spraying methods include a two-fluid spray method that uses compressed air to atomize the particles, an ultrasonic method that uses an ultrasonic element to spray a fine mist of 10 μm or less, and a crushing spray method that releases a solution from a rotating body, crushes it, and sprays a fine mist of 1 μm or less.

The drain outlet 46 is a connection port for connecting to a drain pipe that discharges water or dirt generated within the bathroom space outside the bathroom space. The second cathode extraction solution 24a is transported to the drain outlet 46 from the cathode side extraction solution tank 42 through the cathode side extraction solution bathroom piping 45. The second cathode extraction solution 24a, which is hypochlorous acid water mainly composed of NaClO and NaOH and has high detergency, can clean dirt from the drain outlet 46 and the drain pipe connected to the drain outlet 46.

As described above, the space sterilization system 40 using the hypochlorous acid water supply device 1 according to this second embodiment can provide the following effects.

(6) The space sterilization system 40 is configured to include a hypochlorous acid water supply device 1 and a mist spray device 44 that is connected in communication with the second anode side flow path 25 and that uses the hypochlorous acid water delivered from the second anode side flow path 25 to release a hypochlorous acid water mist into a specified space. With this configuration, even when the hypochlorous acid water mist delivered from the second anode side flow path 25 is released into a specified space, residual components remaining in the specified space are suppressed. In other words, because the hypochlorous acid water delivered from the second anode side flow path 25 is hypochlorous acid water with reduced residual components generated by the electrolysis of salt water, when sterilizing a specified space, it is possible to suppress the occurrence of metal corrosion caused by residual components while maintaining sterilization performance.

(7) In the space sterilization system 40, the bathroom space is provided with a drain outlet 46 for discharging water generated within the bathroom space, and the second negative electrode side flow path 26 is connected in communication with the drain outlet 46, so that the hypochlorous acid water discharged from the second negative electrode side flow path 26 can be introduced into the drain outlet 46. In this manner, highly detergency-enhancing hypochlorous acid water containing an alkaline solution in which cations that cause residual components are concentrated is circulated from the hypochlorous acid water discharged from the second negative electrode side flow path 26 to the drain outlet 46 (and the drain pipe connected to the drain outlet 46), allowing the drain pipe to be cleaned with the alkaline solution.

The present invention has been described above based on the embodiments, but the present invention is in no way limited to the above embodiments, and it is readily apparent that various improvements and modifications are possible within the scope of the present invention.

The hypochlorous acid water supply device of the present invention is a device that can continuously supply hypochlorous acid water that has reduced residual components contained in hypochlorous acid water, which is mainly composed of HClO and is produced by electrolyzing salt water. By spraying a mist of this hypochlorous acid water, it is a useful means of disinfecting mold and bacteria in the bathroom space while also inhibiting corrosion of metals and other materials used in the bathroom.

1 Hypochlorous acid water supply device 2 Hypochlorous acid water generation unit 3 Hypochlorous acid water treatment unit 4 First positive electrode 5 First negative electrode 6 First negative/positive electrode spacer 7a First positive electrode packing 7b First negative electrode packing 8a First positive electrode side of tank housing 8b First negative electrode side of tank housing 9 First negative/positive electrode solution supply port 9a First negative/positive electrode supply solution 10 First positive electrode solution extraction port 10a First positive electrode extraction solution 11 First negative electrode solution extraction port 11a First negative electrode extraction solution 12 First negative/positive electrode flow path 12a First negative/positive electrode flow path hole 13 Electrolysis power supply 14 Second positive electrode 15 Second negative electrode 16 Diaphragm 17 Second positive electrode side spacer 18 Second negative electrode side spacer 19a Second positive electrode packing 19b Second negative electrode packing 20a Second anode side chamber housing side 20b Second cathode side chamber housing side 21 Second anode solution supply port 21a Second anode supply solution 22 Second anode solution extraction port 22a Second anode extraction solution 23 Second cathode solution supply port 23a Second cathode supply solution 24 Second cathode solution extraction port 24a Second cathode extraction solution 25 Second anode side flow path 25a Second anode side flow path hole 26 Second cathode side flow path 26a Second cathode side flow path hole 27 Electrodialysis power supply 28 Anode side connection tube 29 Anode side supply pump 30 Cathode side connection tube 31 Cathode side supply pump 40 Space sterilization system 41 Anode side extraction solution tank 42 Anode side extraction solution tank 43 Anode side extraction solution bathroom piping 44 Mist spray device 45 Cathode side extraction solution bathroom piping 46 drain outlet

Claims (7)

a hypochlorous acid water generation unit that continuously generates hypochlorous acid water by electrolysis from salt water supplied into a serpentine membrane-less electrolysis flow path by passing current between a pair of first cathode and anode electrodes;
a hypochlorous acid water treatment unit that continuously treats the hypochlorous acid water supplied from the hypochlorous acid water generation unit into each of the serpentine membrane-equipped electrolysis channels by passing current between a pair of second cathode and anode electrodes;
Equipped with
A hypochlorous acid water supply device that supplies hypochlorous acid water discharged from the electrolysis flow path on the positive electrode side of the hypochlorous acid water treatment unit to the outside. the membrane-less electrolysis flow path includes a planar first anode, a planar first cathode facing the first anode, and a spacer member provided between the first anode and the first cathode;
2. The hypochlorous acid water supply device according to claim 1, wherein the pair of first cathode and anode electrodes are configured in a serpentine shape by exposing the first anode and the first cathode to the membraneless electrolysis flow path by the spacer member. the membrane-equipped electrolysis flow path comprises a serpentine first flow path in which a second anode is exposed and extended along the flow path, a serpentine second flow path arranged in parallel to and facing the first flow path and in which a second cathode is exposed and extended along the flow path, and a diaphragm arranged to separate the first flow path and the second flow path and allowing permeation of cations contained in a solution flowing through the flow paths,
the pair of second negative-positive electrodes are configured in a serpentine shape by exposing the second positive electrode to the first flow path by a first spacer member and exposing the second negative electrode to the second flow path by a second spacer member;
The hypochlorous acid water supply device according to claim 2, wherein the first flow path and the second flow path are configured so that the hypochlorous acid water supplied from the hypochlorous acid water generation unit flows in the same direction. the second anode having a planar shape; the diaphragm having a planar shape facing the second anode; and the first spacer member provided between the second anode and the diaphragm, exposing the second anode and the diaphragm to an inside of the first flow path along a flow path,
the first flow path is formed by the second positive electrode and the diaphragm, which are exposed along the flow path, and the first spacer member;
the second negative electrode having a planar shape; the diaphragm which is planar and faces the second negative electrode; and the second spacer member which is provided between the second negative electrode and the diaphragm and exposes the second negative electrode and the diaphragm into the second flow path along the flow path,
The hypochlorous acid water supply device according to claim 3, characterized in that the second flow path is composed of the second negative electrode and the diaphragm exposed along the flow path, and the second spacer member. The hypochlorous acid water generating unit and the hypochlorous acid water treatment unit are connected in communication with each other through a flow path.
a supply pump for supplying the hypochlorous acid water from the hypochlorous acid water generation unit to the diaphragm-equipped electrolysis flow path;
The hypochlorous acid water supply device according to claim 3 or 4 , characterized in that the supply pump supplies the hypochlorous acid water from the hypochlorous acid water generation unit to the first flow path and the second flow path at a constant flow rate. The hypochlorous acid water supply device according to any one of claims 3 to 5 ,
A sterilization device that is connected in communication with the first flow path and releases hypochlorous acid water mist into a predetermined space using hypochlorous acid water delivered from the first flow path;
A space sterilization system comprising: a drain pipe for discharging water generated in the specified space is provided in the specified space,
The second flow path is connected to the drain pipe and configured to allow hypochlorous acid water discharged from the second flow path to be introduced into the drain pipe. The space sterilization system according to claim 6.