JP7715704B2 - Sterilized water production device and method for producing sterilized water - Google Patents

Description

The present invention relates to an apparatus and method for producing sterilizing water containing hypochlorous acid or chlorous acid.

It is widely known that hypochlorous acid or disinfectant water containing chlorous acid as its main component is harmless to the human body and has excellent disinfecting effects. Hypochlorous acid is contained at approximately 10% in a sodium hypochlorite aqueous solution, which is made by diluting sodium hypochlorite with water to an effective chlorine concentration of approximately 200 ppm and a pH of approximately 8.6. It has long been known that the proportion of hypochlorous acid increases by lowering the pH to make it a weak acid, reaching nearly 100% at a pH of around 5.

A known method for producing disinfectant water containing hypochlorous acid or chlorous acid as its main component is to mix a sodium hypochlorite aqueous solution or a sodium chlorite aqueous solution with an acidic aqueous solution such as hydrochloric acid.

Figure 5 shows the abundance ratios of chlorine molecules, hypochlorous acid, and hypochlorite ions at each pH when they are in equilibrium. 501 in Figure 5 shows the abundance ratio of hypochlorous acid, which exceeds 80% in the pH range of approximately 4 to 7. From this, it can be said that in order to ensure the stable existence of hypochlorous acid, it is necessary to maintain a stable pH in the range of 4 to 7.

Figure 4 shows the abundance ratios of carbonic acid, bicarbonate ions, and carbonate ions at each pH when they are in equilibrium. 401 in Figure 4 shows the abundance ratio of bicarbonate ions, which is higher between pH 6 and pH 10. In this pH range, bicarbonate ions are present, which have a buffering effect against pH changes, making the pH of the solution less likely to change.

In order to steadily produce sterilized water, it is important to efficiently and stably generate bicarbonate ions, which have a buffering effect, and to maintain the sterilized water at a weakly acidic pH of 6 to 7, at which point hypochlorous acid can stably exist.

Another known method for producing disinfectant water containing hypochlorous acid as its main component is the electrolysis of a hydrochloric acid solution. Other known methods include injecting a sodium chloride solution into an electrolytic cell with a diaphragm between the anode and cathode and electrolyzing it to produce a hypochlorous acid solution on the anode side, and directly electrolyzing a mixed aqueous solution of hydrochloric acid and sodium chloride.

In addition, methods for using the sterilizing water produced using the above method include mixing a sodium hypochlorite aqueous solution and an acidic aqueous solution in a dedicated device, or producing sterilizing water in a dedicated electrolysis device and then using the sterilizing water discharged from the device by taking it out through a stop valve or faucet.

The method of producing sterilizing water by mixing a sodium hypochlorite or sodium chlorite aqueous solution with an acidic aqueous solution has the advantage of being easy to produce, but it has the problem that it is difficult to control the amount of acidic aqueous solution to be mixed, and if the amount of acidic aqueous solution is even slightly too much, the pH will drop rapidly, entering the gasification region and generating chlorine gas or chlorine dioxide gas.

One device that can control the reaction with an acidic aqueous solution and stably produce sterilizing water containing hypochlorous acid or chlorous acid is one that produces sterilizing water by mixing a sodium hypochlorite aqueous solution or a sodium chlorite aqueous solution with carbon dioxide gas (see Patent Document 1).

Patent Document 1 describes a method and apparatus for producing disinfectant water with a predetermined chlorine concentration by diluting a sodium hypochlorite aqueous solution or a sodium chlorite aqueous solution with tap water, well water, seawater, etc., which includes a branching process and mechanism for branching and supplying the tap water, well water, or seawater into at least two or more pipelines, and a process and mechanism for adding a sodium hypochlorite aqueous solution or a sodium chlorite aqueous solution to the tap water, well water, or seawater upstream of the branching process and mechanism to produce disinfectant water; or a process and mechanism for producing disinfectant water by mixing an aqueous solution of sodium hypochlorite or sodium chlorite diluted with tap water, well water, seawater, etc. with an aqueous solution of an acid such as hydrochloric acid, sulfuric acid, or acetic acid diluted with tap water, well water, seawater, etc. "The invention relates to a method and apparatus for producing sterilizing water, characterized in that it has a mechanism for supplying carbon dioxide gas to a pressure vessel at a predetermined pressure equal to or higher than atmospheric pressure, or a process and apparatus for producing sterilizing water by electrolyzing a sodium chloride solution or seawater in a diaphragm-less electrolytic cell or a diaphragm-equipped electrolytic cell, a process and mechanism for supplying carbon dioxide gas to a pressure vessel at a predetermined pressure equal to or higher than atmospheric pressure, a process and mechanism for spraying and/or sprinkling the sterilizing water into the pressure vessel through each of the branched pipelines, and further has a process and mechanism for simply supplying water, a drainage process and mechanism for draining the sterilizing water from the pressure vessel, and a water level maintaining process and mechanism for storing the sprayed and/or sprinkled and supplied sterilizing water at the bottom of the pressure vessel at a predetermined level" (paragraph [0013]).

It is also known that when mixing a sodium hypochlorite aqueous solution or a sodium chlorite aqueous solution with carbon dioxide gas to produce sterilizing water, the solution is mixed or stirred using a static mixer (see Patent Documents 2 and 3).

Japanese Patent Application Laid-Open No. 2006-320899 Japanese Patent Application Laid-Open No. 2009-297696 JP 2014-50828 A

In the device described in Patent Document 1, when a sodium hypochlorite solution or a sodium chlorite solution is sprayed into a pressure vessel filled with carbon dioxide gas, the sprayed droplets react with the carbon dioxide gas before landing on the surface of the sterilizing water accumulated at the bottom of the pressure vessel, producing hypochlorous acid or chlorous acid. However, the above device has the problem that the level of the sterilizing water changes due to malfunction of the water level maintenance mechanism (float), changing the flight time of the sprayed sterilizing water in the carbon dioxide gas, making it impossible to produce sterilizing water with a stable pH.

Patent document 2 describes a carbon dioxide-containing sterilizing water generating device that mixes a sodium hypochlorite aqueous solution or a sodium chlorite aqueous solution with carbon dioxide gas and stirs it using a static mixer or similar device (claims 5 and 6). However, it also states that the structure of the stirrer is not important (paragraph [0031]), and that the sodium hypochlorite is mixed before the carbon dioxide gas is mixed (paragraph [0030]), so the effect of mixing the two in a different order and stirring them in a static mixer is unclear.

Patent Document 3 describes an apparatus that mixes sodium hypochlorite or sodium chlorite (disinfectant) with carbon dioxide gas to produce disinfectant water, and has a mixing section such as a static mixer in the middle of the water supply pipe (claims 2 and 6). However, it also states that the device has a special structure in order to use negative pressure to suck up the disinfectant and mix it with the raw water, and that the mixing section is not necessary (paragraph [0034]). There is no specific description of the static mixer, and the effects of using a static mixer are unclear.

In addition, there is a problem in that the pH of sterilized water produced using conventional equipment such as those described above begins to change to a neutral range after about a week, and the pH changes to a range where hypochlorous acid cannot exist stably.

The present invention aims to solve these conventional problems and provide an apparatus that produces sterilized water containing hypochlorous acid or chlorous acid with a more stable pH.

The present invention employs the following means to solve the above problems.
(1) An apparatus for producing sterilized water containing hypochlorous acid or chlorous acid, comprising, between a raw water inlet and a sterilized water outlet, a carbon dioxide gas injection pipe having a check valve, a sodium hypochlorite aqueous solution or sodium chlorite aqueous solution injection pipe having a check valve, and a stirring tank having a static mixer with a stirring blade inserted into the pipe, and having a pumping section that sends raw water upward, and the carbon dioxide gas injection pipe and the sodium hypochlorite aqueous solution or sodium chlorite aqueous solution injection pipe are connected to a main pipe from the raw water inlet to the stirring tank inlet in this order, with the sodium hypochlorite aqueous solution or sodium chlorite aqueous solution injection pipe on the upper side, and the main pipe is connected to the inlet of the stirring tank, and the lower part of the pipe of the static mixer in the stirring tank has a hole that serves as an inlet for raw water to which carbon dioxide gas and the sodium hypochlorite aqueous solution or sodium chlorite aqueous solution have been added, and a discharge pipe that discharges sterilized water containing hypochlorous acid or chlorous acid from the sterilized water outlet is connected to the outlet of the pipe of the static mixer.
(2) The sterilizing water producing apparatus of (1) above, wherein the sodium hypochlorite aqueous solution or the sodium chlorite aqueous solution is transported by a tube pump.
(3) The sterilized water producing apparatus according to (1) or (2), wherein the static mixer is made of resin.
(4) A sterilizing water manufacturing apparatus according to any one of (1) to (3), wherein a tee fitting for injecting carbon dioxide gas is connected to the main pipe, and a tee fitting for injecting a sodium hypochlorite aqueous solution or a sodium chlorite aqueous solution is connected immediately after the tee fitting for injecting carbon dioxide gas, the tee fitting for injecting carbon dioxide gas is connected to the carbon dioxide gas injection pipe, and the tee fitting for injecting a sodium hypochlorite aqueous solution or a sodium chlorite aqueous solution is connected to the sodium hypochlorite aqueous solution or a sodium chlorite aqueous solution injection pipe.
(5) A sterilizing water manufacturing apparatus according to any one of (1) to (4), in which the particle Reynolds number for carbon dioxide bubbles having a representative length (diameter) of 0.3 mm, calculated by the following formula (1), in the water flow path from the connection position of the carbon dioxide gas injection pipe in the main pipe through the stirring tank to the sterilizing water outlet, is 500 or less.
Particle Reynolds number = (flow rate * carbon dioxide bubble diameter) / (water dynamic viscosity * pipe cross-sectional area) ... (1)
(6) Any of the sterilizing water producing apparatuses according to (1) to (5), wherein the flow rate of water in the flow path from the raw water inlet through the stirring tank to the sterilizing water outlet is 500 L per hour or less, the diameters of the main pipe, the static mixer pipe and the discharge pipe are 11 mm or more, and 1 to 8 holes with a diameter of 4 mm or more are provided in the static mixer pipe.
(7) The sterilized water manufacturing apparatus according to any one of (1) to (6), wherein the static mixer in the stirring tank constitutes a hydrocyclone that separates coarse bubbles and fine bubbles of carbon dioxide gas from the raw water to which the carbon dioxide gas and the sodium hypochlorite aqueous solution or the sodium chlorite aqueous solution have been added.
(8) The sterilizing water producing apparatus according to any one of (1) to (7), which has a component that separates the sterilizing water from the excess carbon dioxide gas that has not dissolved in the stirring tank and releases the excess carbon dioxide gas into the atmosphere.
(9) A method for producing sterilizing water containing hypochlorous acid or chlorous acid, using a sterilizing water producing apparatus having a pipe for injecting carbon dioxide gas, a pipe for injecting a sodium hypochlorite or sodium chlorite aqueous solution, and a stirring tank having a static mixer with a stirring blade inserted into the pipe between a raw water inlet and a sterilizing water outlet, injecting carbon dioxide gas from the pipe for injecting carbon dioxide gas into a main pipe from the raw water inlet to the stirring tank inlet, which has a pumping section for sending raw water upward, and then injecting sodium hypochlorite from the pipe for injecting a sodium hypochlorite or sodium chlorite aqueous solution. a sodium hypochlorite aqueous solution or a sodium chlorite aqueous solution is injected into the stirring tank, raw water to which carbon dioxide and a sodium hypochlorite aqueous solution or a sodium chlorite aqueous solution have been added is supplied from the main pipe to the stirring tank, the raw water is introduced through an inlet (hole) provided at the bottom of the tube of the static mixer in the stirring tank, and the raw water is stirred by the static mixer to produce sterilized water containing hypochlorous acid or chlorous acid, and the sterilized water containing hypochlorous acid or chlorous acid is discharged from a sterilized water outlet of a discharge pipe connected to the outlet of the tube of the static mixer.
(10) The method for producing sterilized water according to (9), wherein the particle Reynolds number for carbon dioxide bubbles having a representative length (diameter) of 0.3 mm, calculated by the following formula (1), of water in a flow path from the connection position of the carbon dioxide gas injection pipe in the main pipe through the stirring tank to the sterilized water outlet is 500 or less.
Particle Reynolds number = (flow rate * carbon dioxide bubble diameter) / (water dynamic viscosity * pipe cross-sectional area) ... (1)
(11) The method for producing sterilized water according to (9) or (10), wherein the flow rate of water in the flow path from the raw water inlet through the stirring tank to the sterilized water outlet is 500 L per hour or less, the diameters of the main pipe, the static mixer pipe, and the discharge pipe are 11 mm or more, and 1 to 8 holes with a diameter of 4 mm or more are provided in the static mixer pipe.

The present invention makes it possible to obtain disinfectant water containing hypochlorous acid or chlorine dioxide from sodium hypochlorite aqueous solution or sodium chlorite aqueous solution by the stable pH adjusting action of carbon dioxide gas.

In addition, mixing carbon dioxide gas and sodium hypochlorite aqueous solution or sodium chlorite aqueous solution into raw water in the piping, and stirring with a static mixer in the stirring tank after mixing, is effective in stabilizing the pH of the resulting sterilized water.

The sterilized water produced by the device of the present invention can maintain a pH of 5.6 to 5.8, at which hypochlorous acid can stably exist, for more than six months.

FIG. 1 shows a typical embodiment of the present invention. Static mixer mixing principle A diagram showing the relationship between pH and oxidation-reduction potential (ORP) of dissociated chlorine species Diagram showing the abundance ratio of dissociated species of carbonic acid Diagram showing the abundance ratio of chlorine dissociation species

Hereinafter, one embodiment of the present invention for producing sterilized water containing hypochlorous acid or chlorous acid will be described with reference to the drawings.
1 is a diagram showing the structure of a typical sterilized water production apparatus of the present invention. Raw water 14 such as tap water, well water, or seawater is supplied to a main pipe 9 from a raw water inlet 1.
As a pre-process before supplying raw water 14 to the raw water inlet 1, it is preferable to provide a pressure reducer (regulator) that keeps the pressure of tap water (raw water) constant.
The main pipe 9 extending from the raw water inlet 1 to the inlet of the agitation tank 7 has a pumping section that sends the raw water 14 upward.

A carbon dioxide injection tee fitting 10 is connected to the pumping section of the main pipe 9, from which carbon dioxide 16 that has passed through the carbon dioxide injection pipe 4 and the carbon dioxide injection check valve 3 is added to the raw water.

A tee fitting 11 for injecting sodium hypochlorite aqueous solution (sodium chlorite aqueous solution when producing sterilizing water containing chlorous acid) is connected immediately after the tee fitting 10 for injecting carbon dioxide gas in the pumping section of the main pipe 9, and the sodium hypochlorite aqueous solution 17 transported from there by a tube pump 12 passes through the sodium hypochlorite aqueous solution injection pipe 6 and the sodium hypochlorite injection check valve 5 and is added to the raw water.

The tee fitting 11 that supplies the sodium hypochlorite aqueous solution is located above the tee fitting 10 that injects carbon dioxide, so that the carbon dioxide floats between the tee fittings 10 and 11 due to buoyancy, faster than the flow of tap water supplied from the raw water inlet 1, and dissolution is promoted.
The raw water to which carbon dioxide gas and an aqueous solution of sodium hypochlorite have been added passes through a main pipe 9 and enters the agitation tank 7 .

The raw water that has entered the stirring tank 7 passes through the static mixer inlet 13 and enters the static mixer 8 where it is stirred.
The raw water to which carbon dioxide gas and an aqueous solution of sodium hypochlorite have been added is stirred in a static mixer 8 to produce sterilized water containing hypochlorous acid.
The static mixer 8 is a pipe with an agitating blade structure, as shown in Figure 2, in which multiple twisted blades are arranged in series at different angles. The raw water is agitated by passing through the agitating blade along the path indicated by the arrows in Figure 2. Since the static mixer is in direct contact with the raw water, it must be made of a material that is not susceptible to corrosion, and in this embodiment, it is made of resin. Polyvinyl chloride, polyacetal, polypropylene, etc. can be used.

The stirring tank 7 is a hydrocyclone that separates coarse bubbles from fine bubbles of carbon dioxide gas from the raw water to which carbon dioxide gas and an aqueous solution of sodium hypochlorite have been added, and is effective in stabilizing the pH.
The main pipe 9 is connected to the top of the stirring tank 7, and the static mixer inlet (hole) 13 is provided at the bottom. In the process of moving raw water containing carbon dioxide gas from the bottom to the top of the static mixer 8, bicarbonate ions are efficiently generated by the fine bubbles of carbon dioxide gas that are separated to the top.
As will be described later, by reducing the flow rate of raw water in the main pipe 9, the residence time of fine carbon dioxide bubbles in the static mixer 8 also increases. In principle, the static mixer 8 mixes without destroying the laminar flow structure, and it is therefore believed that bicarbonate ions are efficiently generated by the fine carbon dioxide bubbles.
In order to increase the residence time, it is preferable to provide the static mixer inlet 13 as close to the bottom as possible.

The stirring tank 7 is essentially a continuous reactor, and is a hybrid of a tubular reactor (static mixer 8) and a tank-type reactor. It is preferable to monitor the temperature and pressure to stabilize the quality of the produced sterilized water 15. For this reason, it is preferable to provide a temperature sensor and a pressure sensor in the main pipe 9, which is the flow path, and in the stirring tank 7.
A microphone may be attached to the flow path to analyze its impedance. This allows monitoring of the generation of carbon dioxide microbubbles, and by analyzing the sound, the quality of the sterilized water can be determined, which helps to stabilize the quality of the sterilized water.

An outlet of the tube of the static mixer 8 in the stirring tank 7 is connected to a discharge pipe 18 , and the sterilizing water 15 containing hypochlorous acid is discharged from the sterilizing water outlet 2 of the discharge pipe 18 .
It is preferable to have a member that separates the excess carbon dioxide gas that has not dissolved in the stirring tank 7 from the sterilizing water 15 and releases the excess carbon dioxide gas into the atmosphere.

It is preferable that the flow rate of water in the flow path from the raw water inlet 1 through the stirring tank 7 to the sterilizing water outlet 2 is 500 L/hour or less, that the diameters of the main pipe 9 from the raw water inlet 1 to the inlet of the stirring tank 7, the pipe of the static mixer 8, and the discharge pipe 18 connected to the outlet of the static mixer 8 are 11 mm or more, and that the pipe of the static mixer 8 is provided with 1 to 8 holes with a diameter of 4 mm or more, so that a laminar flow is formed with a particle Reynolds number of 500 or less for carbon dioxide bubbles with a diameter of 0.3 mm as a representative length.
Here, the flow path from the raw water inlet 1 through the stirring tank 7 to the sterilizing water outlet 2 comprises the flow path of the main pipe 9 from the raw water inlet 1 to the inlet of the stirring tank 7, the flow path from the outlet of the main pipe 9 in the stirring tank 7 (inlet of the stirring tank 7) to the static mixer inlet 13, the flow path within the static mixer 8, and the flow path of the discharge pipe 18 from the outlet of the static mixer 8 to the sterilizing water outlet 2.

The particle Reynolds number is calculated as follows: (flow rate * carbon dioxide bubble diameter) / (water dynamic viscosity * pipe cross-sectional area). Since the carbon dioxide bubble diameter and water dynamic viscosity are constant, the particle Reynolds number decreases as the flow rate decreases and/or the pipe cross-sectional area increases, i.e., the pipe diameter increases. In the present invention, because the water flow rate is small, a stable laminar flow with a small particle Reynolds number can be obtained even if the pipe diameter is reduced.
The flow rate of water (raw water and sterilized water) is preferably 500 L per hour or less, and more preferably 300 L per hour or less.
The diameters of the main pipe 9 and the discharge pipe 18 are preferably 11 mm or more, and more preferably 13 mm or more. The upper limit of the diameters of the main pipe 9 and the discharge pipe 18 is preferably 20 mm or more, and more preferably 15 mm, in order to obtain a stable laminar flow with little change in the Reynolds number. The diameter of the pipe of the static mixer 8 is preferably 15 mm or more, and more preferably 20 mm or more. The diameter of this pipe is preferably 65 mm or less, and more preferably 30 mm or less. The outer periphery of the pipe of the static mixer 8 is preferably provided with 1 to 8 holes with a diameter of 4 mm or more, and more preferably 2 to 4 holes with a diameter of 6 mm or more. The upper limit of the diameter of these holes is preferably 20 mm, and more preferably 15 mm.
A particle Reynolds number of 500 or less will result in laminar flow, but a particle Reynolds number of 300 or less is more preferable, and a particle Reynolds number of 250 or less is even more preferable.
By setting the particle Reynolds number as described above, the residence time of carbon dioxide bubbles in the flow path can be increased, and the time that the raw water mixed with sodium hypochlorite comes into contact with carbon dioxide can be increased, thereby efficiently producing bicarbonate ions that have a pH buffering effect.

The results of calculating the particle Reynolds number for carbon dioxide bubbles with a representative length of 0.3 mm in diameter are shown in Table 1.

As described above, when the water flow rate is 300 L/h and the diameter of the pipe is 13 mm, the particle Reynolds number for carbon dioxide bubbles with a diameter of 0.3 mm is 211.
If the diameter of the pipe is 11 mm when the water flow rate is 500 L/h, the particle Reynolds number will be 491, which is less than 500, so it is preferable that the diameter of the main pipe and discharge pipe be 11 mm or more.
The diameter of the pipe (corresponding to the piping) of a static mixer is usually about 20 mm, so the particle Reynolds number of the raw water (sterilized water) in the static mixer is smaller than the particle Reynolds number of the raw water flowing through the main piping.
Furthermore, if four 10 mm diameter holes (the hole diameter corresponds to the piping diameter) are provided on the outer periphery of the static mixer pipe, the true piping cross-sectional area through which the raw water flows in the stirring tank will be four times larger, and if this piping cross-sectional area is used, the particle Reynolds number will be 149 when the water flow rate is 500 L/h. Even if four 6 mm diameter holes are provided, the particle Reynolds number in the stirring tank will be 500 or less. Therefore, the particle Reynolds number in the flow path from the connection position of the carbon dioxide gas injection pipe in the main pipe, through the stirring tank, to the sterilized water outlet will be 500 or less.

Carbon dioxide gas and an aqueous solution of sodium hypochlorite are added to the raw water, which is stirred by the static mixer 8. The ratio of hypochlorous acid increases, and the pH value decreases, turning the water into sterilized water with a pH of 5.6 to 5.8.
The produced sterilized water can maintain a pH of 5.6 to 5.8, at which hypochlorous acid can stably exist, for six months or more.

The relationship between the pH and oxidation-reduction potential (ORP) of the sterilized water produced in this embodiment is shown in FIG.
3, it can be seen that equilibrium reactions such as Cl ₂ (g) + 2e ^- = 2Cl ^- (chloride ion vs. chlorine gas) shown at 102, ClO ^- + H ₂ O + 2e ^- = Cl ^- + 2OH ^- (hypochlorous acid ion vs. chloride ion) shown at 103, and ClO ₂ ^- + H ₂ O + 2e ^- = ClO ^- + 2OH ^- (chlorate ion vs. hypochlorous acid ion) shown at 104 exist in the region above pH 7, and hypochlorous acid is not present. In the region of pH 5.6 to pH 5.8, which is the pH of sterilizing water, equilibrium reactions of HClO + H ⁺ + e ^- = 1/2Cl ₂ (g) + H ₂ O (hypochlorous acid vs. chlorine gas) shown at 101 and HClO + H ⁺ + 2e - = Cl ^- + H ₂ O (hypochlorous acid vs. chloride ion) shown at 100 exist, indicating the presence of hypochlorous acid molecules.

1 Raw water inlet, 2 Sterilized water outlet, 3 Carbon dioxide gas injection check valve, 4 Carbon dioxide gas injection piping, 5 Sodium hypochlorite solution injection check valve, 6 Sodium hypochlorite solution injection piping, 7 Mixing tank, 8 Static mixer, 9 Main piping, 10 Carbon dioxide gas injection tee fitting, 11 Sodium hypochlorite solution injection tee fitting, 12 Tube pump, 13 Static mixer inlet, 14 Raw water, 15 Sterilized water, 16 Carbon dioxide gas, 17 Sodium hypochlorite solution, 18 Discharge pipe, 100 Hypochlorous acid vs. chloride ion, 101 Hypochlorous acid vs. chlorine gas, 102 Chloride ion vs. chlorine gas, 103 Hypochlorous acid ion vs. chloride ion, 104 Chlorate ion vs. hypochlorite ion, 400 Carbonic acid abundance ratio, 401 Bicarbonate ion abundance ratio, 402 Carbonate ion abundance ratio, 500 Abundance ratio of chlorine molecules, 501 Abundance ratio of hypochlorous acid, 502 Abundance ratio of hypochlorous acid ions

Claims (7)

An apparatus for producing sterilized water containing hypochlorous acid or chlorous acid, comprising, between a raw water inlet and a sterilizing water outlet, a carbon dioxide gas injection pipe having a check valve, a sodium hypochlorite or sodium chlorite aqueous solution injection pipe having a check valve, and a stirring tank having a static mixer with a stirring blade inserted into the pipe, and the carbon dioxide gas injection pipe and the sodium hypochlorite or sodium chlorite aqueous solution injection pipe are connected in this order to a main pipe having a pumping section for sending raw water upward and leading from the raw water inlet to the stirring tank inlet, with the sodium hypochlorite or sodium chlorite aqueous solution injection pipe on the upper side. a main pipe connected to the inlet of the stirring tank, the lower part of the pipe of the static mixer in the stirring tank having a hole which serves as an inlet for raw water to which carbon dioxide gas and a sodium hypochlorite aqueous solution or a sodium chlorite aqueous solution have been added, and an outlet pipe for discharging sterilizing water containing hypochlorous acid or chlorous acid from the sterilizing water outlet is connected to the outlet of the pipe of the static mixer , and the static mixer of the stirring tank constitutes a hydrocyclone which separates carbon dioxide gas bubbles in the raw water to which carbon dioxide gas and a sodium hypochlorite aqueous solution or a sodium chlorite aqueous solution have been added into coarse bubbles and fine bubbles . The sterilizing water producing apparatus according to claim 1, wherein the sodium hypochlorite aqueous solution or sodium chlorite aqueous solution is transported by a tube pump. The sterilized water producing apparatus according to claim 1 or 2, wherein the static mixer is made of resin. The sterilizing water manufacturing apparatus according to any one of claims 1 to 3, wherein a tee fitting for injecting carbon dioxide gas is connected to the main pipe, and a tee fitting for injecting a sodium hypochlorite aqueous solution or a sodium chlorite aqueous solution is connected immediately after the tee fitting for injecting carbon dioxide gas, the tee fitting for injecting carbon dioxide gas is connected to the carbon dioxide gas injection pipe, and the tee fitting for injecting a sodium hypochlorite aqueous solution or a sodium chlorite aqueous solution is connected to the sodium hypochlorite aqueous solution or a sodium chlorite aqueous solution injection pipe. The sterilizing water producing apparatus according to any one of claims 1 to 4, wherein the particle Reynolds number for carbon dioxide bubbles having a representative length (diameter) of 0.3 mm, calculated by the following formula (1), in the water flow path from the connection position of the carbon dioxide gas injection pipe in the main pipe through the stirring tank to the sterilizing water outlet, is 500 or less.
Particle Reynolds number = (flow rate * carbon dioxide bubble diameter) / (water dynamic viscosity * pipe cross-sectional area) ... (1) The sterilized water production apparatus according to any one of claims 1 to 5, wherein the flow rate of water in the flow path from the raw water inlet through the stirring tank to the sterilized water outlet is 500 L/hour or less, the diameters of the main pipe, the static mixer pipe, and the discharge pipe are 11 mm or more, and the static mixer pipe has 1 to 8 holes with a diameter of 4 mm or more. The sterilizing water producing apparatus according to any one of claims 1 to 6 , further comprising a member for separating the sterilizing water from the excess carbon dioxide gas that has not dissolved in the stirring tank and releasing the excess carbon dioxide gas into the atmosphere.