FR3141703A1 - System and process for producing a disinfectant solution based on hypochlorous acid - Google Patents

Abstract

The invention relates to a system for producing a disinfectant solution comprising: - a dilution tank (300) comprising a water inlet (302) allowing filling with water, - an electrolyzer (100) arranged in- below the tank (300) and comprising: - an electrolysis enclosure (110) storing alkaline chloride in solid form, - a set of electrodes (120), - a conduit (200) connecting the enclosure and the tank, and in which: - filling the tank causes the enclosure to be filled through the conduit to prepare an aqueous solution containing chloride ions by dissolving part of the alkaline chloride, - electrolysis of the solution aqueous water in the enclosure produces hypochlorous acid, at least part of which migrates from the enclosure towards the tank via the conduit, the at least part of the hypochlorous acid having migrated being diluted in the water present in the enclosure. the tank in order to form the disinfectant solution. Figure to be published with the abstract: Fig. 1

Description

System and process for producing a disinfectant solution based on hypochlorous acid Technical area.

The invention relates to a system for producing a disinfectant solution containing hypochlorous acid. The invention also relates to a method using this system.

The field of the invention is that of the manufacture and design of devices and systems for the electrochemical production of hypochlorous acid. The invention finds particular application in the field of disinfection of, for example, but not limited to, water, air, hard or soft surfaces, plant, animal or human surfaces, surfaces of medical devices.

State of the art.

Hypochlorous acid (CAS No. 7790-92-3) is a weak inorganic acid with the formula HOCl. It partially dissociates in water to produce the hypochlorite ion (OCl⁻) according to the reaction of equation 1:
HOCl_{( aq )}⇌ H⁺ _{( aq )}+OCl^- _{( aq )} pKa of approximately 7.5 (1)

In aqueous solution, the distribution of the two chlorine species (HOCl/OCl−) depends on the pH of the water as indicated by annexed.

As can be seen from the , hypochlorous acid is the predominant species at pH < 7.6 and the hypochlorite form becomes predominant at pH > 7.6 (alkaline pH). At pH values below 3.5, chlorine gas begins to form. To maintain the hypochlorous acid (HOCl) solution in a stable form, maximize its antimicrobial activities, and minimize unwanted side products, the pH should preferably be maintained between 3.5 and 7.5.

Hypochlorous acid (HOCl) is, moreover, a major bactericidal compound in innate immunity. It is produced naturally in mammals by white blood cells to fight infections. It has germicidal properties against a wide range of microorganisms (bacteria, viruses, fungi, etc.). Compared to sodium hypochlorite (main constituent of bleach) which is often used as a sterilizing agent, hypochlorous acid is said to be 80 to 120 times more effective while being less irritating to the skin.

Hypochlorous acid has many uses such as in water treatment, hygiene and food safety, sanitation of all types of surfaces, objects or food, as well as in pharmacy and medicine, particularly for wound care. and skin disinfection. It should be noted that hypochlorous acid is approved by the United States Food and Drug Administration (FDA) as a biocidal product. Furthermore, the European Commission approved, in July 2021, active chlorine released from hypochlorous acid (EC number: 232-232-5) as an active substance in biocidal products used for human hygiene. The recent outbreak of the novel coronavirus Covid-19 has not only led to a stock shortage of alcohol-based disinfection products on the market, but also demonstrated the importance of hypochlorous acid in disinfecting places susceptible to be contaminated by the Covid-19 coronavirus. As a result, today we are seeing a growing demand for disinfectant solutions based on hypochlorous acid in a wide variety of application sectors (e.g. water treatment, food processing, cosmetics, medicine, etc.).

Different systems and processes for preparing disinfectant solutions containing hypochlorous acid have been proposed in the prior art. Among the known systems and processes, we can, by way of example, cite:
- the hydrolysis of chlorine gas according to the reaction of equation 2 below,
- the acidification of hypochlorite ion according to the reaction of equation 3 below,
- the electrolysis of an aqueous solution of sodium chloride according to the reactions of equations 4-6 below.
Cl_2(g)+H₂O_(L)⇌ HOCl_{( aq )}+H⁺ _{( aq )}+Cl^- _{( aq )}(2)
OCl^- _{( aq )}+H⁺ _{( aq )}⇌ HOCl_{( aq )} (3)
2Cl^- _{( aq )}→ Cl_2(g)+ 2nd^- (4)
2H₂O_(L)+ 2nd^-→ H_2(g)+ 2OH^- _{( aq )}(5)
Cl_2(g)+ 2OH^- _{( aq )}→ OCl^- _{( aq )}+Cl^- _{( aq )}+H₂O_(L) (6)

The process according to equation 2 is rapid and effective for preparing disinfectant solutions containing hypochlorous acid. However, it is rarely used due to the risks inherent in the handling of chlorine gas and the dangers linked to the storage of the latter. .

The process according to equation 3 consists of acidifying an aqueous solution of a hypochlorite salt such as calcium or sodium hypochlorite, with an aqueous solution of an acidifier such as hydrochloric acid to obtain a disinfectant solution containing hypochlorous acid. However, this process requires very precise control of pH and temperature during the acidification process to prevent or reduce the generation of toxic chlorine gas. In addition, this process requires the manufacturing, transportation and storage of hypochlorite salts and acid products which are corrosive chemicals.

The process according to the reaction of equations 4-6, is most widely used for the production of disinfectant solutions containing hypochlorous acid. This process generally does not require the presence of chemicals in the water other than an alkaline chloride such as sodium or potassium chloride. In particular, this process consists of supplying a tank or enclosure provided with an electrolytic cell comprising electrodes including at least one anode and at least one cathode, with an aqueous solution containing a certain proportion of alkaline chloride, in particular sodium chloride, at electrolyze this aqueous solution in order to produce an aqueous solution of hypochlorous acid, then transfer, for example by pumping, this solution of hypochlorous acid into another enclosure or tank to be diluted there with water to obtain a disinfectant solution containing hypochlorous acid. It should be noted that the reaction of equation 4 (oxidation of chloride ions) takes place at the level of at least one anode and leads to the formation of chlorine gas and that of equation 5 (reduction of water) takes place at the level of the at least one cathode and leads to the generation of dihydrogen.

As a reminder, the electrolytic cells involved in known processes exist in two categories:
- The first category includes split cells which use membranes to maintain complete separation of anode and cathode products in the cells, thus, the chlorine gas produced at each anode according to the equation dissolves in water to form hypochlorous acid according to the reaction of equation 2 mentioned above.
- The second category includes undivided cells that do not use membranes. In this case, the chlorine gas generated at each anode can directly react with the hydroxide anion produced at each cathode to form hypochlorite ions according to the reaction of equation 6, which hypochlorite ions can be in equilibrium with the hypochlorous acid according to the reaction of equation 1 mentioned above.

The electrolysis processes and systems of the prior art all have one or more of the following drawbacks:
- The disinfectant solutions produced are generally contaminated with significant quantities of chloride salt and/or are very diluted and/or have a low concentration of hypochlorous acid (< 3 ppm).
- They generally involve large installations and/or are relatively complex and therefore expensive.
- They do not meet the needs of the user who wishes to have the possibility of adapting the production of the disinfectant solution according to the desired concentration of hypochlorous acid. As mentioned above, the applications for using the disinfectant solution are multiple, it is of course desirable to give the user the possibility of choosing the concentration of hypochlorous acid which is best suited to the disinfection operation he is carrying out. must perform.

The invention aims to remedy all or part of the aforementioned drawbacks. Another objective of the invention is to propose a system or process for producing a disinfectant solution based on hypochlorous acid which leaves the possibility for a user to obtain said disinfectant solution with the concentration of hypochlorous acid which is most suitable. to the use he wishes to make of it. Yet another objective of the invention is to propose such a system or method which is simple in its design, easily achievable and easy to implement, on a small or large scale and which is inexpensive. Another object of the invention aims to propose such a system or method which allows the user to monitor the production of said disinfectant solution in an efficient manner.

Presentation of the invention.

The solution proposed by the invention is a system for producing a disinfectant solution containing hypochlorous acid. This system is remarkable in that it includes:
- a dilution tank dedicated to the preparation of the disinfectant solution, which tank has a water inlet allowing said tank to be filled with water,
- at least one electrolyser placed below the dilution tank, and comprising:
-- an electrolysis chamber storing alkaline chloride in solid form,
-- at least one set of electrodes comprising at least one anode and at least one cathode arranged in the electrolysis enclosure,
-- a conduit putting the electrolysis enclosure and the dilution tank into fluid communication.

This system is further remarkable in that:
- filling the dilution tank with water causes the electrolysis enclosure to be filled with water through the conduit to prepare an aqueous solution containing chloride ions by dissolving part of the alkaline chloride stored in said electrolysis enclosure , And,
- the electrolysis of the aqueous solution in the enclosure produces hypochlorous acid, at least part of which migrates from the electrolysis enclosure towards the dilution tank via the conduit, the at least part of the acid l The hypochlorous having migrated is diluted in the water present in the dilution tank in order to form the disinfectant solution.

The system for producing a disinfectant solution containing hypochlorous acid according to the present invention has numerous advantages, in particular that of being simple in its design, easily achievable, easy to implement, on a small or large scale and little expensive. In addition, the system according to the present invention allows a user to obtain the disinfectant solution with the concentration of hypochlorous acid which is best suited to the use he wishes to make of it. In fact, the user can adjust this system so that the disinfectant solution is concentrated in hypochlorous acid with the desired free chlorine content (for example, 5 ppm, 100 ppm, 250 ppm, 1500 ppm, 3000 ppm, or more than 3000 ppm). For this, he has at his disposal different ways to adjust the system, he can for example increase the number of electrolyzers and/or the number of sets of electrodes per electrolyzer and/or the number of electrodes per set of electrodes . It will be noted that the system according to the present invention does not include any transfer means, for example of the pump type, to transfer the hypochlorous acid (and/or the hypochlorite ions) generated in the electrolysis enclosure from the latter to the storage tank. dilution in which hypochlorous acid must be mixed with water to form the disinfectant solution. It should also be noted that before electrolysis, the dilution tank placed above the electrolysis enclosure contained water, and that after electrolysis this water was replaced by the disinfectant solution.

Other advantageous features of the invention are listed below. Each of these characteristics can be considered alone or in combination with the remarkable characteristics defined above, and be the subject, where appropriate, of one or more divisional patent applications:

Advantageously, the electrolysis of the aqueous solution in the electrolysis enclosure is adjusted to generate the formation of gas bubbles, so that said bubbles create turbulence capable of forcing the migration of at least part of the hypochlorous acid from the electrolysis chamber to the dilution tank via the conduit.

The at least one electrolyzer may be one or two or three or more than three electrolyzers.

The at least one set of electrodes may be one or two or more than two sets of electrodes.

Preferably, the at least one set of electrodes further comprises a plurality of bipolar electrodes interposed between an anode and a cathode of the at least one set of electrodes.

Preferably, the at least one anode, the at least one cathode and the plurality of bipolar electrodes of the at least one set of electrodes are all in the form of flat plates, parallel and regularly spaced from each other.

In a variant embodiment, the at least one set of electrodes comprises a plurality of anodes and a plurality of cathodes, which pluralities of anodes and cathodes are in the form of flat plates arranged in parallel rows of alternating polarity.

The electrolysis enclosure of the at least one electrolyzer may have a capacity of at least 10 liters.

The dilution tank may further comprise means for breaking (or reducing the size) the bubbles of chlorine gas which may come from in the electrolysis enclosure of the at least one electrolyser in order to promote the dissolution of the chlorine gas in the water, said means for breaking said gaseous chlorine bubbles being arranged at the bottom of the dilution tank at least opposite the conduit putting the electrolysis enclosure and the dilution tank into fluid communication.

The means for breaking the gas bubbles can consist of at least one flat plate having perforations whose diameter is sufficient to reduce the size of the gas bubbles to dimensions favoring the dissolution of chlorine in the water.

Preferably, the perforations of the at least one plate have a diameter of less than 10 mm, preferably less than 1 mm.

In particular, when the means for breaking the gas bubbles consist of several flat and perforated plates, which plates are superimposed in such a way that the perforations of one plate are offset relative to the perforations of another plate which is adjacent to it

Advantageously, the system according to the present invention further comprises a measuring device comprising:
- a sensor suitable for measuring the free chlorine content in the disinfectant solution forming in the dilution tank,
- a display adapted to display the free chlorine content measured by the free chlorine sensor.

Typically, the system according to the present invention further comprises regulation means for regulating the pH of the disinfectant solution forming in the dilution tank.

Advantageously, the system according to the present invention further comprises a control unit functionally connected to the device for measuring the free chlorine content, which control unit is adapted to compare the free chlorine content measured by the sensor and a threshold value of the free chlorine content, and interrupt the electrolysis when the free chlorine content measured by the sensor is equal to or greater than the threshold value of the free chlorine content.

In particular, the threshold value of the free chlorine content is set at a maximum value selected in a range of 5 ppm to 3000 ppm, in particular in a range of 10 ppm to 1500 ppm.

In practice, the dilution tank has a water inlet which is connected to a water source by a water supply circuit comprising, towards the dilution tank, a solenoid valve and a circulation pump.

In practice again, the dilution tank has a sampling outlet for the disinfectant solution, which sampling outlet is connected to a tap provided on the water supply circuit between the solenoid valve and the circulation pump so that the sampling line forms with the pump and the part of the water supply circuit located after this pump a recirculation loop which is configured to circulate the disinfectant solution from the sampling outlet to the water inlet.

Preferably, the free chlorine measuring device is placed on the recirculation loop, in particular on the sampling line, so as to allow continuous measurements to be carried out on the disinfectant solution.

The aqueous solution to be electrolyzed may have a pH of 3 to 8, preferably a pH of 6 to 8.

In another aspect, the present invention relates to a process for producing a disinfectant solution containing hypochlorous acid. This process is remarkable in that it includes:
a) a step of providing a system according to the present invention;
b) a step of filling the dilution tank of said system with water, and in which filling the dilution tank with water causes the filling of the electrolysis enclosure of the at least one electrolyzer of said system by the conduit putting said electrolysis enclosure and said dilution tank into fluid communication, in order to prepare an aqueous solution containing chloride ions by dissolving part of the alkaline chloride stored in said electrolysis enclosure;
c) a step of applying an electric current to the electrodes of the at least one set of electrodes of said at least one electrolyzer to electrolyze the aqueous solution containing chloride ions in said enclosure in order to produce hypochlorous acid, and in which at least part of the hypochlorous acid migrates from said enclosure towards said dilution tank via said conduit, the at least part of the hypochlorous acid having migrated being diluted in the water present in said dilution tank. dilution to form the disinfectant solution;
d) a step of measuring the free chlorine content of the disinfectant solution forming in said dilution tank;
e) a step of interrupting the electrolysis when the free chlorine content measured in step d) reaches a desired free chlorine content value for the disinfectant solution;
f) optionally, a step of measuring the free chlorine content by a sensor capable of measuring the free chlorine content of the disinfectant solution forming in said dilution tank;
g) optionally, the interruption of the electrolysis provided for in step e) is taken care of by a control unit adapted to compare the free chlorine content measured by the sensor in step f) and a threshold value of the free chlorine content and to interrupt electrolysis when the free chlorine content measured by the sensor is equal to or greater than the threshold value of the free chlorine content;
h) optionally, a step of measuring at least one intrinsic parameter of the disinfectant solution forming in the dilution tank, which intrinsic parameter is chosen from the list of parameters including pH, temperature, conductivity, and hardness ;
i) optionally, a step of regulating the pH of the disinfectant solution forming in the dilution tank.

In particular embodiments, the current voltage applied to the electrodes, in step c) of the method, is between 1 and 15 volts, preferably between 2 and 10 volts.

Advantageously, the disinfectant solution containing the hypochlorous acid has a pH of approximately 5.1 to approximately 6.9, preferably a pH of approximately 6.5.

Preferably, in optional step g) of the process, the threshold value of the free chlorine content is set at a maximum value selected in a range from 5 ppm to 3000 ppm, in particular in a range from 10 ppm to 1500 ppm .

Brief description of the figures.

Other advantages and characteristics of the invention will appear more clearly on reading the description of the preferred embodiment which follows, with reference to the appended drawings, produced as indicative and non-limiting examples and in which:
Other advantages and characteristics of the invention will appear more clearly on reading the description of the preferred embodiments which follows, with reference to the appended drawings, produced as indicative and non-limiting examples and in which:
is an illustration of dissociation curves of hypochlorous acid in water as a function of pH;
is a schematic representation of a system for producing a disinfectant solution according to the invention equipped with a dilution tank and an electrolyzer;
is a schematic representation of another system for producing a disinfectant solution according to the invention equipped with a dilution tank and two electrolyzers;
is a photographic representation of a system for producing a disinfectant solution according to the invention equipped with a dilution tank and three electrolyzers;
is a perspective view of an example of an electrolyzer suitable for the present invention;
is a perspective view of an example of a hollow tube which can serve as a support element for a set of electrodes of the system according to the invention;
is a perspective view of an example of a set of electrodes suitable for the present invention;
is a schematic representation of the system of further equipped with a device for measuring the free chlorine content;
is a schematic representation of the system of additionally equipped with a control unit;
is a schematic representation of the system of according to a first variant, the system being further equipped with a recirculation loop and the dilution tank of which is provided with level detectors;
is a schematic representation of the system of according to another alternative embodiment, the system also being equipped with another form of recirculation loop and the dilution tank of which is provided with level detectors;
is a schematic representation of an example of a dilution tank of the system of the invention according to an alternative embodiment, in which the dilution tank is provided with a tubular gauge.

Description of the embodiments.

The present description is given on a non-limiting basis, each characteristic exposed only in one embodiment being able to be generalized to other embodiments. Likewise, one or more features set forth only in one embodiment may be combined with one or more other features set forth only in another embodiment.

The present description is given on a non-limiting basis, each characteristic exposed only in one embodiment being able to be generalized to other embodiments. Likewise, one or more features set forth only in one embodiment may be combined with one or more other features set forth only in another embodiment. We note now that the appended figures are very simplified, the elements represented there are therefore not necessarily to scale in relation to each other or from one figure to another. Each reference retains the same meaning from one figure to another.

The present invention primarily aims at a system intended to produce a disinfectant solution based on hypochlorous acid, preferably a disinfectant solution containing hypochlorous acid with a free chlorine content greater than 5 ppm. This system can be used by users to produce the disinfectant solution on a small scale, on site or on demand or on an industrial scale.

By “ppm”, we must understand parts per million. You should know that in the case of an aqueous solution, a concentration of 1 ppm can be expressed as follows: 1 ppm = 1 mg/kg ≈ 1 mg/L.

The system which is the subject of the invention comprises:
- at least one electrolyzer 100, and
- a 300 dilution tank dedicated to the preparation of the disinfectant solution.

By “at least one electrolyser” we must understand an electrolyser (see ), two electrolyzers (see ), three electrolyzers (see ) or more than three electrolyzers. Also, for the sake of simplification, only the case of the system with a single electrolyzer, represented on the , will be discussed in the remainder of the description, but the system and the method according to the present invention operates in a similar manner with two, three or more electrolyzers, and, advantageously, with high performance in the production of hypochlorous acid and disinfectant solutions containing it.

Furthermore, the electrolyser 100 used comprises an electrolysis enclosure 110 equipped with at least one set of electrodes 120.

By “at least one set of electrodes”, it is necessary to understand a set of electrodes (see for example the ), two or more sets of electrodes (see ). Here too, for the sake of simplification, only the case of the electrolyzer with a single set of electrodes, represented on the , will be discussed in the remainder of the description, but the system and the method according to the present invention operates in a similar manner with two or more sets of electrodes, and, advantageously, with high performance in the production of hypochlorous acid and disinfectant solutions containing it.

On the other hand, as we will describe subsequently, the dilution tank 300 of the system provided with at least one bottom outlet 303. In principle, each at least one bottom outlet 303 is intended to be used with an electrolyser 100. The dilution tank 300 can be provided with two, three or more than three bottom outlets 303 but of which only one bottom outlet 303 is connected to an electrolyzer 100. For example, in relation to the , a single electrolyzer 100 equips the system according to the invention, and the dilution tank 300 is shown with a single bottom outlet 303. However, the dilution tank 300 can be a tank with several bottom outlets in which the outlets of unused bottom can be closed by a suitable closing means (e.g. cap, tap, closing valve, etc.).

Electrolyser 100

The set(s) of electrodes 120 of the at least one electrolyser 100 are each intended to be supplied with electricity by an energy source 101 producing an electric current. This can be direct and/or pulsed current.

Referring to the , the electrolyser 100 comprises an electrolysis enclosure 110 storing alkaline chloride in solid form, and generally having an upper opening 111, which can be closed in a sealed manner by a removable cover 130.

The alkaline chloride stored in solid form in the electrolysis enclosure 110 is intended to be mixed with water in this enclosure 110 in order to produce the aqueous solution containing chloride ions whose electrolysis makes it possible to obtain hypochlorous acid.

By “alkaline chloride” is meant according to the present invention sodium chloride, potassium chloride and their mixture. For the sake of simplification, only the case of sodium chloride will be discussed in the remainder of the description, but the system and the process according to the present invention applies to all types of alkaline chloride.

By “solid form” is meant according to the present invention any solid form having a weight of approximately 5 g to 30 g. Preferably, the solid form of alkaline chloride such as sodium chloride is chosen from lozenges, tablets, and lozenges. The advantages of using alkaline chloride in solid form will be discussed later.

The enclosure 110 can be made of any suitable electrically insulating material and resistant to corrosion by the aqueous solution containing alkaline chloride such as sodium chloride as well as by the products generated during electrolysis. Preferably, the enclosure 110 is made of glass or rigid plastic, preferably transparent, for example, polyvinyl chloride (PVC), polypropylene reinforced with glass fibers (PRV), or Acrylonitrile-Butadiene-Styrene. (ABS) or polycarbonate (PC). It is clear, however, that this list is not exhaustive. The use of a transparent material, glass or plastic, makes it possible to carry out a visual inspection of the internal components of the cell 110 and to observe electrolysis during normal operations.

In practice, the enclosure 110 has the shape of a cylinder with a circular section which extends in the vertical direction. Its height varies for example from 15 cm to 150 cm or more than 150 cm, and its diameter varies for example from 10 cm to 80 cm, or more than 80 cm. The shapes and dimensions described for the enclosure 110 are given only by way of example, because the latter can have any other shape (e.g. parallelepiped or cylinder of oval section, or other shape) and appropriate dimensions, most suitable for the use for which the enclosure 110 and the system according to the invention are intended. Furthermore, the enclosure 110 can have any shape generated by a straight line which moves parallel to an axis, resting on two fixed planes. Thus the circular section of a cylindrical enclosure can be truncated to present a flat part 112 in almost its entire height as illustrated in the .

As shown in Figures 2 and 8 to 12, the electrolysis enclosure 110 of the system according to the invention is provided with a set of electrodes 120, which is intended to be connected to the energy source 101 producing a current electric. We can recall here that the invention is not limited to this embodiment and that two, three or even more than three sets of electrodes 120 can equip the electrolysis enclosure 110. The number of sets of electrodes 120 to be used can be chosen according to the desired overall performance (e.g. production time of the disinfectant solution containing hypochlorous acid). Indeed, the Applicant was able to observe that with a system according to the invention comprising a single electrolysis enclosure 110, the more the number of sets of electrodes increases, the greater the production time of the disinfectant solution having a free chlorine content. data is reduced. This is highlighted in [Table 1] of the examples and which shows the effect of the number of sets of electrodes 120 per electrolyzer 100 on the production time of the disinfectant solution according to the present invention.

The set(s) of electrodes 120 each comprise at least one anode and one cathode (not shown). We recall here that, according to definitions well known to those skilled in the art, must be understood: by “anode” a positive electrode, which will be the seat of the oxidation reaction of equation no. 4 (2Cl ^- _{( aq )} ⇌ Cl _2(g) + 2e ^- ) mentioned above, and by “cathode” a negative electrode, which will be the seat of the reduction reaction of equation n°5 (2H ₂ O _(l) + 2e ^- ⇌ H _2(g) + 2OH ^- _{( aq )} ) mentioned above.

The electrodes of the (at least one) set of electrodes 120 can be made of titanium, of titanium covered with a catalytic coating containing metal oxides, such as titanium oxide, ruthenium oxide, oxide iridium and tin oxide; made of titanium alloy; made of hastelloy® alloy (nickel-chrome-molybdenum alloy) or any other corrosion-resistant metal or alloy. For example, such a catalytic coating can consist of 45 to 55% titanium oxides, 25 to 30% ruthenium oxide and 20 to 20% iridium. The electrodes may have a shape such as flat plates or other suitable shapes best suited to the use for which the (at least) one set of electrodes 120 is intended in the context of the present invention. Preferably, the electrodes of (at least) one set of electrodes 120 are in the form of flat plates made of sufficient thickness (e.g. 1 mm to 4 mm) to be rigid. These flat plates can have a width ranging for example from 25 mm to 100 mm and a length sufficient to be able to insert the (at least) one set of electrodes 120 in the diametrical direction in the enclosure 110 and so that the electrodes of the at least one set of electrodes 120 is at least partially arranged inside the enclosure 110. As an example for an enclosure of 25 cm in diameter, the flat plates can have a width of less than 25 cm, for example a length between 15 cm to 24 cm. In particular, the inter-electrode space is between 0.1 cm and 1.2 cm, preferably between 0.1 cm and 0.5 cm. It should be noted that the closer the electrodes are to each other, the greater the contact/exchange surface area per unit volume and therefore the less voltage required. Indeed, as the distance increases, the energy requirement to pass the electric current (carried by the ions) through the aqueous solution containing chloride ions increases. Increasing the distance increases the electrical resistance and therefore at the same current intensity, the voltage must be increased (Ohm's law).

In particular embodiments of the invention, not shown, the electrodes of (at least) one set of electrodes 120 are two electrodes in number including an anode and a cathode, which anode and cathode are in the form of flat plates parallel to each other, and are sufficiently spaced from each other, for example 0.1 cm and 1.2 cm, preferably between 0.1 cm and 0.5 cm.

In other particular embodiments of the invention, not shown, a set of electrodes 120 may comprise two or more anodes and two or more cathodes, which anodes and cathodes are in the form of flat plates parallel to each other, and are alternated in the set of electrodes 120 and sufficiently spaced from each other, for example 0.1 cm and 1.2 cm, preferably between 0.1 cm and 0.5 cm.

Preferably, the (at least) one set of electrodes 120 further comprises one or more bipolar electrodes arranged between an anode and a cathode of the (at least) one set of electrodes 120.

By the term "bipolar electrode" is meant according to the present invention, an electrode located at an intermediate potential between an electrode at a higher potential and another electrode at a lower potential, so that said electrode acts simultaneously as an anode. on the part opposite the lower potential electrode and as a cathode on the part opposite the other. In the case of flat electrodes, anodic type reactions occur on one side and cathodic type reactions on the other side.

The bipolar electrode(s) may be made of any corrosion-resistant metal or alloy as for the other electrodes of the at least one set of electrodes 120. Furthermore, the bipolar electrode(s) may also have a substantially similar shape or identical to that of the anode and the cathode of (at least one) set of electrodes 120. Preferably, the anode, the cathode and the bipolar electrode(s) are all in the form of flat, parallel and regularly spaced plates from each other, for example from 0.1 cm to 1 cm. The number of bipolar electrodes per set of electrodes 120 can for example range from 1 to 20, in particular from 2 to 18, for example can be equal to 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16 or 17.

It should be remembered that, per set of electrodes 120, the number of anode(s) may be equal to one or more and the number of cathode may be equal to one or more.

Bipolar electrodes are well known in the art (JP2004237165A, EP0065889A1, WO2012172118A1).

Preferably, the at least one set of electrodes is of the non-divided type (not

In particular embodiments, not shown, the electrolyser 100 or the system according to the invention may also comprise at least one switch or an electrical control circuit usable to reverse periodically, for example every 90 min with a pause time of 5 min, the polarities of the electrodes of the at least one set of electrodes, so that the electric current circulates, between the electrodes, in one direction, then in the opposite direction (bipolar operation). The purpose of reversing the polarity of the electrodes is to eliminate or prevent a build-up of deposits (e.g. calcium deposits) on the electrode surfaces during operation. It leads to improved operation of the electrodes and extends their lifespan. When reversing polarities, a pause time after depolarization and repolarization of the electrodes of 5 min is optimal, this makes it possible to avoid the formation of short circuits between the electrodes of at least one set of electrodes 120. These short circuits can gradually deteriorate these electrodes. The reversal of the electrode polarities and the pause time can be controlled for the control unit 600 which will be described in more detail later.

Advantageously, the (at least one) set of electrodes 120 is configured or adapted to be inserted, in a removable and sealed manner, into the electrolysis enclosure 110 through a respective opening 114 provided for this purpose in a wall of the electrolysis enclosure 110, and so that, in use, the electrodes of said (at least one) set of electrodes 120 are at least partly immersed in the aqueous saline solution to be electrolyzed. Maintaining the position of the set(s) of electrodes 120 in the wall of the enclosure 110 can be achieved by any means suitable to those skilled in the art, in particular by insertion with bayonet fitting or by screwing onto the wall through which the (at least one) set of electrodes 120 is inserted. The opening 114 of the wall 112 has for example a diameter of approximately 90 mm.

In particular embodiments (not shown), the (at least one) set of electrodes 120 is in the form of or is arranged in a cylindrical or parallelepiped housing, insertable in the electrolysis enclosure 110 and having appropriate peripheral openings or drillings so that, in operation, the electrodes of the (at least one) set of electrodes are in contact with the aqueous solution to be electrolyzed, on the one hand, and the alkaline chloride such as sodium chloride, in solid form, cannot become embedded between the electrodes of the (at least one) set of electrodes (120) and cause short circuits in the electrolyser 100, on the other hand.

In a particular embodiment, presented in particular on the , the electrolysis enclosure 110 is provided with elongated hollow tubes 121, of horizontal axis, each arranged in the enclosure 110. Each of these hollow tubes 121 serves as a support element for a set of electrodes 120 and is designed to facilitate the insertion of the set of electrodes 120 into the enclosure 110, on the one hand, and the removal of the set of electrodes 120 from the enclosure 110, on the other hand, for example when one wishes to carry out control operations to be carried out on the electrodes and/or replacement of the latter. In practice, the elongated hollow tubes 121 each have peripheral holes provided so that, in use, the electrodes of (at least) one set of electrodes 120 inserted in the respective hollow tube 121 are in contact with the aqueous solution. saline electrolysis. Such peripheral drillings also aim to prevent alkaline chloride such as sodium chloride, in solid form, from becoming embedded between the electrodes of the (at least one) set of electrodes (120) and causing short circuits in the electrolyzer. The elongated hollow tubes can be made of a material substantially identical or similar to that constituting the enclosure 110. Their peripheral holes can have a diameter of 10 mm or less.

On the , there is shown an elongated hollow tube 121 whose end which is intended to be fixed in the wall 112 of the enclosure 100, has an external thread 119 intended to fix by screwing a set of electrodes 120 provided with a counter -thread (not shown). Of course, other means or fixing techniques can be provided than those described with reference to the to ensure the reversible and waterproof fixing of a set of electrodes 120 in an elongated hollow tube 121.

Concerning the arrangement of (at least one) set of electrodes 120 in the electrolysis enclosure 110, reference can be made to patent application WO2012172118A1 in the name of the applicant.

Generally speaking, referring to Figures 2, 3, 8 to 12, the enclosure 110 is surmounted by a cover 130. This is configured or adapted to close the upper opening 111 of said enclosure 110, so as to waterproof. This cover 130 is removable so as to allow the loading of the alkaline chloride in solid form into the enclosure 110, on the one hand, and to allow easy access to the interior of the enclosure 110, in particular with a view to being able to carry out emptying and/or cleaning operations of the enclosure 110, on the other hand. The cover 130 is made of a material substantially similar or identical to that of the enclosure 110, in particular PVC, ABS or PC.

The cover 130 can be fixed to the enclosure by screwing. On the , the upper part of the enclosure 110 has an external thread 113 intended to fix by screwing the cover 130 provided with a counter-thread (not shown). Of course, other means or fixing techniques can be provided than those described with reference to the to ensure the reversible closing of the enclosure 110. As an example of these other means or techniques, we can cite those commonly used in the field of opening and closing systems for pressure cookers.

Furthermore, the cover 130 can be equipped with a suitable seal (not shown), for example made of elastomer, making it possible to create or reinforce the seal between the enclosure 110 and the cover 130.

In Figures 2 to 5, and 8 to 12, the cover 130 is provided with a conduit of 200 (called communication conduit). This is intended to allow fluid communication between the interior and exterior of the electrolysis enclosure 110. The communication conduit 200 can be used to fill the electrolysis enclosure 110 with water for the dissolution of the alkaline chloride which is already loaded there in solid form (via the upper opening 110) in order to form the aqueous solution containing chloride ions to be electrolyzed. The communication conduit 200 also allows the movement of hydrogen gas, at least a portion of hypochlorous acid and, where appropriate, chlorine gas generated in the enclosure 110 during the electrolysis reaction from this enclosure 110 towards the dilution tank 300 dedicated to the preparation of the disinfectant solution as will be described in more detail later.

This communication conduit 200 is made of a material substantially similar or identical to that of the enclosure 110 or the cover 130, in particular PVC, ABS or PC. It preferably has the shape of a cylindrical tube with a circular base. In use, it opens through its lower end into the enclosure 110 through a cover orifice 131 arranged in the removable cover 130. The free upper end of this communication conduit 200 is intended to be connected to the dilution tank 300 as will be described below.

Such a communication conduit 200 can be made in one piece with the cover 130 or be fixedly attached in a sealed manner, for example via a rubber sealing ring (not illustrated) in this cover 130.

In particular embodiments of the invention (not shown), the electrolysis enclosure may also comprise in its lower part an outlet orifice allowing it to be emptied. This outlet orifice can for example be closed by any suitable closing means, for example by a plug, a tap or the like.

An example of an electrolyzer which can be used with the system according to the present invention is described in patent application WO2012172118A1 in the name of the Applicant, or is marketed by the latter under the brand name Chlor'in ( https://www .chlor-in.com/concept-chlor-in-p3.php).

In the appended figures, the conduit 200 is a straight and vertical conduit or substantially straight and vertical, but it is possible to provide an inclined conduit, or a helical, vertical or inclined conduit.

Dilution tank

The system according to the present invention further comprises a dilution tank 300 in which the disinfectant solution will be prepared by diluting the hypochlorous acid coming from the at least one electrolyser in water supplied by the water source S .

The tank 300 is intended to be placed above the at least one electrolyser 100. The number of electrolysers can be 1, 2 or 3 or more as indicated above. As can be seen in Figures 2, 3 and 4, this tank 300 is placed above, respectively, 1, 2 and 3 electrolyzers 100. The number of electrolyzers 100 is chosen according to the desired overall performance (e.g. . production time of the disinfectant solution containing hypochlorous acid, desired hypochlorous acid content for the disinfectant solution). Indeed, the Applicant was able to observe that for a dilution tank 300 of a given volume of water, the more electrolyzers there are, the more the disinfectant solution is obtained with a given concentration of hypochlorous acid in a shorter time. This is highlighted in [Table 1] of the examples presented below, and which shows the effect of the number of electrolyzers 120 on the production time of the disinfectant solution according to the present invention.

The tank 300 according to the invention has at its upper part a water inlet 302 and at its bottom 305 at least one bottom outlet (or orifice) 303 (one bottom outlet per electrolyzer).

The water inlet 302 is dedicated to the introduction of water to fill water in the dilution tank 300. It is intended to be connected to a water supply source ''S'' such as by for example a tap or a municipal water pipe, or other.

In practice, the water to be brought into the dilution tank 300 is tap water, but it is obviously possible to use natural spring water, distilled water, or deionized or filtered water.

Also, in a particular embodiment (not shown), the system according to the present invention may further comprise a water filter arranged between the water supply source S and the water inlet 302 of the dilution tank 300. This water filter aims to eliminate, or at least reduce, any organic compounds (or organic pollutants) which may be present and which could interact with chlorine, among other products of water electrolysis saturated with sodium chloride. The water filter can be of any type known to those skilled in the art such as for example a particulate filter (cartridge filter, microfiltration membrane, sand); an activated carbon filter; an ultrafiltration membrane; a membrane contactor or a gas filtration membrane.

The bottom outlet 303 of the dilution tank 300 is configured or adapted to connect to the communication conduit 200 of the electrolyzer 100 in order to allow fluid communication between this dilution tank 301 and the interior of the enclosure. electrolysis 110 of this electrolyzer 100.

The bottom outlet 303 can be connected to the communication conduit 200 of the electrolyser 100, for example, by means of any type of suitable quick and tight coupling known to those skilled in the art (see for example US5580099A; US20190063652A1; EP0829671A2 , US20180252347A1).

By “bottom outlet 303” we designate a bottom orifice of the tank 300 or a suitable bottom conduit inserted into said bottom orifice of the tank 300, which bottom conduit can be attached and mounted on the dilution tank 300 in order to to be able to be fixed there permanently, or in a removable manner.

The dilution tank 300 can have any shape (e.g. parallelepiped or cylindrical with an oval section, or other shape) and appropriate dimensions, best suited to the use for which the enclosure 110 and the system according to the invention are intended. In practice, the tank 300 has the shape of a parallelepiped with a square or rectangular section. The volume of the dilution tank 300 can range from 1 liter to 500 liters or more. Of course, the invention is not limited to these shapes or dimensions for the dilution tank 300.

In practice, the dilution tank 300 is made of a material substantially similar or identical to that of the enclosure 110, in particular PVC, ABS or PC. It is preferably protected against ambient light, for example by an auxiliary device for protection against ambient light (not shown). This auxiliary device can take the form of a box or a cabinet whose walls are made of opaque material, for example, but not limited to, wood, opaque plastic (e.g. PVC, HDPE), opaque glass, metal (e.g. .

In particular embodiments of the invention (not shown), the dilution tank 300 may further comprise at its lower part an outlet orifice allowing the distribution of the disinfectant solution or the emptying of the tank 300. This orifice of outlet can be closed for example by means of a tap or be connected by connection means (e.g. pipe) to a storage tank capable of receiving the disinfectant solution or to a flexible pipe for distributing the latter.

In particular embodiments of the invention (not shown), the dilution tank 300 may further comprise means for breaking the bubbles of chlorine gas which may come from the electrolysis enclosure 110 of the at least one electrolyzer 100 in order to promote the dissolution of chlorine gas in water, said means for breaking said bubbles of chlorine gas being arranged at the bottom of the dilution tank 300 at least opposite the conduit 200 putting said electrolysis enclosure into fluid communication and the dilution tank 300. The means for breaking the gas bubbles can be constituted by at least one flat plate having perforations whose diameter is sufficient to reduce the size of the gas bubbles to dimensions favoring the dissolution of the chlorine in the 'water. Preferably, the perforations of the at least one plate have a diameter of less than 5 mm, preferably less than 1 mm. Preferably, the means for breaking the gas bubbles consist of several flat and perforated plates. These plates are generally superimposed in such a way that the perforations of one plate are offset in relation to the perforations of another plate adjacent to it.

In a variant, not shown, the means for breaking the gas bubbles consist of a strainer made of stainless metal or plastic (e.g. PVC) and with mesh whose size is less than 5 mm, preferably less than 1 mm .

Use of the system according to the invention.

The system according to the present invention can be mounted in the manner described below, which can be easily deduced from the preceding explanations in particular in relation to the , and without this description of the assembly or use of the system according to the invention having to be interpreted in a limiting sense.

Step 1: we start with the electrolysis enclosure 110, which is in practice already equipped with (at least) one set of electrodes 120. We charge the electrolysis enclosure with alkaline chloride such as sodium chloride in solid form. It can be indicated that the quantity of alkaline chloride such as sodium chloride to be loaded into the electrolysis chamber must be sufficient to prepare an aqueous solution in which part of the alkaline chloride such as sodium chloride is dissolved, for example a brine or an aqueous solution saturated with this alkaline chloride. We recall here that in the case of sodium chloride, it has a solubility of approximately 357 g per liter of water at 0°C. In a particular example, approximately 25 kg of sodium chloride in the form of pellets of approximately 15 g are loaded into an electrolysis chamber with a capacity of approximately 40 liters. We can also indicate that sodium chloride in the form of pellets of approximately 15 g is available under the brand name AXAL ^® PRO, from the company K+S Minerals and Agriculture GmbH, located in Germany. As a variant of the particular example described here, potassium chloride or a mixture of sodium chloride and potassium chloride can be used to prepare the aqueous solution to be electrolyzed.

Step 2: we then close the electrolysis enclosure 110 with its removable cover 130.

Step 3: we place the electrolysis enclosure 110 loaded with alkaline chloride such as sodium chloride, and closed by its cover 130 under the dilution tank 300. In relation to the aforementioned particular example, we choose a tank of dilution of 260 liters for at least one electrolysis chamber whose capacity is approximately 40 liters.

Step 4: the conduit 200 of the electrolyser 100 is connected to the corresponding bottom outlet 303 of the dilution tank 300. The connection can be made by any suitable rapid and waterproof coupling means known to those skilled in the art, as mentioned above. Now, the dilution tank 300 and the electrolysis enclosure 110 of the electrolyser 100 are in fluid communication with one another.

Step 5: we connect the dilution tank 300 to the water supply source S, if necessary, via an appropriate water filter as mentioned above.

Step 6: the water is introduced into the dilution tank 300 until the latter and also the electrolysis enclosure 110 are filled, the latter filling with water via the bottom outlet 303 of the dilution tank 300 and the conduit 200 of the electrolysis enclosure 110 to which this bottom outlet 303 is connected. We can mention here the advantage of using alkaline chloride, such as sodium chloride, in solid form which is that when filling the electrolysis enclosure 110, the alkaline chloride salt remains at the bottom of the latter. .

Step 7: wait sufficient time to allow the formation of chloride ions in the water, by dissolving at least part of the alkaline chloride, such as sodium chloride. In practice, this waiting time is approximately 5 minutes to 1 hour.

Step 8: Once the complete system is assembled, the at least one electrolyser is supplied with electricity via the energy source 101 in order to start the electrolysis itself.

In practice, the electric current supplying the electrodes of the at least one set of electrodes 120 (or electrodes of the at least one electrolyser 100) is a direct current. Alternatively, the electrolysis according to the invention can be carried out with a pulsed current.

The electrolysis in the electrolysis chamber 110 is generally carried out at a pH of approximately 6-8, under a voltage between 1V to 15 V, preferably between 2 and 10 V.

The direct (and/or pulsed) current used can have a current density of between 0.1 A/dm ² and 10 A/dm ² , or even above 10 A/cm ² . Preferably, the electrolysis is carried out with a direct (and/or pulsed) current having a current density of between 0.1 A/dm ² and 5 A/dm ² .

After a period of electrolysis sufficient to obtain a disinfectant solution containing hypochlorous acid with the desired content of free chlorine, the electrolysis is interrupted (we will return to this last point in detail later).

During electrolysis, at least part of the chloride ions present in the aqueous solution contained in the electrolysis enclosure is oxidized at at least one anode of the electrolyzer to generate chlorine (Cl _2(g) ) following the reaction of equation 4 mentioned above. The chlorine thus generated reacts instantly with the water present in the aqueous solution to produce hypochlorous acid (HOCl _{( aq )} ) and hydrochloric acid (HCl _{( aq )} ) following the reversible reaction of equation 2 mentioned above . Parallel to the oxidation reaction of the chloride ions, there is a reduction of water, at the level of at least one cathode of the electrolyzer, into gaseous hydrogen (H _2(g) ) and into hydroxide ions ( OH ^- ) following the reaction of equation 5 mentioned above. Thus, overall the electrolysis of the aqueous solution containing alkaline chloride such as sodium chloride, at a pH of 6 to 8 (pH of city water), leads to the formation of chlorine products (gaseous chlorine, hypochlorous acid and/or hypochlorite ions) and gaseous hydrogen, within the electrolysis enclosure 110. However, the latter is in fluid communication with the dilution tank 300, which is filled with water.

The hydrogen gas, and where appropriate part of the chlorine gas, generated in the electrolysis enclosure 110 therefore takes the conduit 220 of the latter, then the bottom outlet 303 of the dilution tank 300 and then passes through the dilution tank 300 containing the water to discharge into the atmosphere.

On the other hand, the water contained in the dilution tank 300 and the aqueous solution contained in the electrolysis enclosure 110 together form a system which has an automatic tendency to return the concentrations of the chemical species (In this case here: water, hypochlorous acid and/or hypochlorite ions and chloride ions) which compose it homogeneously. This phenomenon of “irreversible” movement of chemical species which tends to homogenize the composition of the system corresponds to what in chemistry-physics is called chemical “diffusion”.

Thus, in this case, the hypochlorous acid and/or the hypochlorite ions as well as the chloride ions therefore tend to move (or migrate) from the aqueous solution from the electrolysis chamber 110 towards the dilution tank 300 and, conversely, water tends to move (or migrate) from the dilution tank 300 towards the electrolysis enclosure 110.

It should be noted that chemical diffusion is a phenomenon which, in principle, occurs very slowly if no agitation accelerates it.

However, it is to the merit of the author of the present invention to have found, despite this highly unfavorable prejudice, that it is possible to produce a disinfectant solution whose free chlorine content (hypochlorous acid and/or ions hypochlorites) can reach 1000 ppm or even more than 1000 ppm in acceptable times, in industrial practice, for example less than 12 hours, by placing the dilution tank 300 above the electrolysis enclosure 110, by connecting them fluidically, and using the movement of hydrogen gas bubbles and, where appropriate, chlorine gas, generated in the aqueous solution of the electrolysis enclosure 110. In fact, this movement of gas bubbles generates tiny vortices which promote the movement or diffusion of at least part of the molecules of hypochlorous acid and/or hypochlorite ions (or chlorine product) of the concentrated medium which is represented in this case by the aqueous solution contained in the electrolysis enclosure 110 towards the least concentrated medium which is represented in this case by the water of the dilution tank 300.

Furthermore, it is possible to adjust the electrolysis so as to generate the formation of gas bubbles, in particular hydrogen gas, so that these bubbles create turbulence capable of forcing the migration of at least part of the hypochlorous acid from the electrolysis chamber 110 to the dilution tank 301. For this, the author of the present invention has shown that increasing the number of electrodes per set of electrodes 120 and/or the number of sets of electrodes by electrolyzer makes it possible to promote the generation of such gas bubbles and to reduce the production time of a disinfectant solution containing hypochlorous acid at a given or desired free chlorine content.

Furthermore, the author of the present invention has found in a surprising and unexpected manner that the disinfectant solutions obtained using the system according to the present invention can possibly contain alkaline chloride such as sodium chloride, but in very low, lower contents. at 1 ppm, which is very advantageous in a process or system for producing disinfectant solutions.

We return here to the notion of “sufficient electrolysis period” mentioned above. In fact, the present invention leaves the choice to the user of the system for producing the disinfectant solution comprising hypochlorous acid to determine for himself the free chlorine content which is best suited to the disinfection operation he plans to carry out. 'carry out, for example air disinfection, disinfection of hard or soft surfaces, disinfection of medical devices, disinfection of the skin, disinfection of cuts on the skin, disinfection of plants (e.g. salads, fruits, vegetables, vines, plants ), disinfection of animal breeding buildings, etc.

Also, to obtain the disinfectant solution with a given free chlorine content which is suitable for the use he wishes to make of it, the user can monitor, during the production process, the free chlorine content of the water contained in the dilution tank 300. Furthermore, when the value of the free chlorine content corresponds to what he desires, the user can interrupt the electrolysis in the electrolyzer(s).

We designate by “free chlorine”: hypochlorous acid (HOCl) and hypochlorite ions (OCl ^- ).

To monitor the progress of the production of the disinfectant solution containing hypochlorous acid, the user can take samples of the disinfectant solution forming in the dilution tank 300 and analyze these samples to determine their free chlorine content. Sample collection and analysis can be carried out on an ad hoc basis or online, preferably online.

The specific determination of the free chlorine content of the disinfectant solution can be carried out according to conventional analysis methods known to those skilled in the art: dosage by colorimetry, acid-base titration, dosage by amperometry, analysis by spectrophotometry ( see e.g. WO2013121294A1), Oxidation-Reduction Potential (ORP) assay.

Preferably, as illustrated in Figures 8 to 12, the system according to the present invention further comprises a measuring device 400 comprising:
- a sensor 411 adapted to measure the free chlorine content in the disinfectant solution forming in the dilution tank 300,
- a display 412 adapted to display the free chlorine content measured by the sensor 411.

The threshold value of the free chlorine content corresponds to a maximum value, chosen, that the free chlorine content of the disinfectant solution forming in the dilution tank 300 must not exceed. It is set by the user, for example, to a value greater than or equal to 5 ppm. It is generally chosen in a range between 5 ppm and 3000 ppm, in particular between 10 ppm and 1500 ppm. It should be remembered that the system according to the present invention could be adjusted, if necessary, for example so as to obtain a concentrated disinfectant solution of hypochlorous acid with a free chlorine content equal to or greater than 3000 ppm, in particular, a content of free chlorine equal to or less than 10,000 ppm

The measuring device 400 with its sensor 411 and its display 412 may be of a type known and commercially available. It can be connected to a measuring tap located below the level of the disinfectant solution present in the dilution tank as shown in the figure. , or in practice, be placed on a recirculation loop 450, as shown in Figures 9 to 12.

The measuring device 400 allows, thanks to its sensor 411, a continuous measurement of the free chlorine content of the disinfectant solution present in the dilution tank, thus allowing real-time monitoring of the production of this disinfectant solution. The continuous display of the free chlorine content measured by the sensor 411 allows the user to monitor, in real time, the production of the disinfectant solution containing hypochlorous acid and to decide to interrupt at any time electrolysis when he considers that the disinfectant solution has a sufficiently high free chlorine content for the use he plans to make of it.

With the aim of automating the monitoring of the production of the disinfectant solution, the system according to the present invention may further comprise a control unit, designated by the reference 600 in Figures 9 to 12. This control unit 600 is functionally connected to the measuring device 400 and is adapted to compare the free chlorine content measured by the sensor 411 and a threshold value of the free chlorine content and to interrupt the electrolysis when the free chlorine content measured by the sensor 411 is equal to or greater than the threshold value of the free chlorine content.

The threshold value of the free chlorine content corresponds to a maximum value, chosen, that the free chlorine content of the disinfectant solution forming in the dilution tank 300 must not exceed. This threshold (or maximum) value can be selected in a range of free chlorine content greater than or equal to 5 ppm, in particular, in a range from 5 ppm to 3000 ppm, for example, a range from 10 ppm to 1500 ppm .

Furthermore, the disinfectant solution forming in the dilution tank 300 generally has a pH greater than 3 and less than 8, in particular from 4 to 7.5. It is preferably maintained or regulated in a pH range of 5 to 7, preferably at a pH of approximately 5.1 to approximately 6.9, in particular at a pH of approximately 6.5.

It should be noted that in the different applications (e.g. disinfection of air, plant, animal or human surfaces, medical devices, etc.) for which the disinfectant solution produced by the system according to the present invention is suitable, a pH of 5.1 to 6.9, in particular, a pH of around 6.5 can be considered optimal.

Also, preferably, the system according to the present invention further comprises a pH probe 413 for measuring or determining the pH of the disinfectant solution present in the dilution tank 300. This pH probe may be of a known and available type in commerce. It can be connected to a measuring tap located below the level of the disinfectant solution present in the dilution tank 300 as shown in the figure. , or in practice, be placed on a recirculation loop 450 (shown in Figures 9 to 12). Alternatively, not shown, the pH probe can be placed immersed in the dilution tank 300 (e.g. use of a digital pH meter with remote probe available under Ref 2201LM from MOINEAU Instruments, France).

In practice, the pH probe 413 is included in the measuring device 400 comprising sensor 411, which measuring device 400 can further be configured to display, thanks to the display 412, the pH value measured by the pH probe 413 in addition to the value of the free chlorine content measured by sensor 411.

The system according to the present invention may further comprise a pH regulating device (not shown) connected to receive a signal from the pH probe 413 and being adapted to inject a pH correcting agent into the dilution tank in response to the signal from the pH probe 413.

By “pH correction agent” we mean any acidic aqueous solution or any basic aqueous solution that does not alter the physicochemical characteristics of hypochlorous acid. Preferably, the pH correcting agent is in the form of an aqueous solution containing an acid, preferably chosen from inorganic acids such as boric acid, hydrochloric acid, phosphoric acid and sulfuric acid and /or organic acids such as acetic acid, citric acid, ascorbic acid and propionic acid.

Typically, the pH regulation device also includes a dosing pump capable of injecting a dose of the pH correcting agent into the disinfectant solution.

The pH regulation device (dosing pump connected to the pH correcting agent reservoir) may be of a type known and commercially available. Its dosing pump can be connected to the dilution tank 300 (embodiment not shown) or be arranged at any location in a recirculation loop, such as the loop 450 shown in Figures 9 to 12.

In practice, the pH 413 probe measures the pH value of the disinfectant solution present in the dilution tank, continuously or periodically, every 10 minutes for example. If the pH value measured by the probe 413 is higher, respectively lower, than a set value, generally set in a pH range of 5 to 7, preferably, a pH range of approximately 5.1 to approximately 6, 9, in particular at a pH of approximately 6.5, the dosing pump of the pH regulating device injects a dose of pH correcting agent so as to decrease, respectively increase the pH of the disinfectant solution until obtaining a pH equal to the set value.

The pH regulation device is generally placed near the pH probe 413 which can be included in the measuring device 400 as mentioned above.

The measurement and regulation of the pH of the disinfectant solution can be automated as for the measurement of the free chlorine content, thanks to the use of the 600 control unit presented previously.

In practice, as shown in Figures 10 to 12, the water inlet 302 of the dilution tank 300 is connected to the water source S by a water supply circuit 420 comprising, in the direction of the dilution tank 300, a valve, preferably a solenoid valve 440 or 441, and a pump 430.

With the aim of homogenizing the disinfectant solution in the dilution tank 300 and carrying out measurements in particular of pH and the free chlorine content of the disinfectant solution, the system according to the present invention may further comprise a recirculation loop, external, designated by reference 450 on the .

This recirculation loop 450 can be formed by a line for sampling at least part of the disinfectant solution, designated by the reference 410 in Figures 10 to 12, and a part of the water supply circuit 420, the sampling line 410 being connected, on one side, to a sampling outlet 307 provided on the dilution tank 300 and, on the other side, to a tap, designated by the reference 421, located on the supply circuit of water 420 between the solenoid valve 440 and the pump 430. This is designed to pump and circulate at least part (or fraction) of the disinfectant solution in the circulation loop 450, from the sampling outlet 307 in direction of the water inlet 302 of the dilution tank 300.

According to a possible variant, shown on the , the two-way solenoid valve 440 is replaced by a three-way solenoid valve 441, a first way 441a of which is connected to the water source S, a second way 441b is connected to the inlet of the pump 430 and a third track 441c is connected to the sampling line at 410, the third track 441c replacing the tap 421 used in the previous embodiment. Closing the first channel 441a and opening the second and third channels 441b and 441c of the solenoid valve 441 makes it possible to form a recirculation loop 450' equivalent to the recirculation loop 450 presented previously.

In practice, as shown in Figures 10 to 12, the sampling outlet 307 is provided in the lower part, on a wall or on the base, of the dilution tank 300 and the water inlet 302 is provided in part upper part of the dilution tank 300. Of course, it is possible to reverse this arrangement. We then place the sampling outlet 307 in the upper part of the dilution tank 300 and the water inlet 302 in the lower part of the dilution tank.

As mentioned above, the sensors or measuring probes (pH and free chlorine level), and the means for regulating the pH of the disinfectant solution can be arranged at the level of such a 450 or 450' recirculation loop. This allows the user to have real-time information on the parameters of the disinfectant solution and therefore to optimally monitor the production of the latter at the concentration desired by the user.

Preferably, the solenoid valve 440 or 441 and the pump 430 are controlled by the control unit 600.

Preferably, the dilution tank 300 is equipped with disinfectant solution level detectors in order to optimize the operation of the recirculation loop 450 or 451' and of the system of the present invention.

In particular embodiments, shown in Figures 10 to 11, three level detectors are placed in the dilution tank 300, namely a low level detector N ₁ , a high level detector N ₂ and an intermediate level detector N ₃ located between the low level N ₁ and high level N ₂ detectors.

In another embodiment, shown on the , the dilution tank 300 is equipped with a tubular gauge 310 which is placed on the exterior wall (or one of the walls) of the dilution tank 300 while being arranged vertically in parallel to the latter. As we can see in this , the tube 310 has a lower end 311 fluidly connected to an opening 306 in the lower part of the dilution tank 300 and an upper end 312 fluidly connected to an opening 307 in the upper part of the dilution tank. Furthermore, a low level detector N ₁ ' is placed at the opening 306 of the dilution tank 300, a high level detector N ₂ ' is placed at the opening 307 of the dilution tank 300 , and an intermediate level detector N ₃ 'located between the low level N ₁ 'and high level N ₂ ' detectors.

The different level detectors N ₁ , N ₂ and N ₃ (or N ₁ ', N ₂ ', and N ₃ ') are intended to be connected to the control unit 600 which can be configured to control, for example, :
- filling the dilution tank 300 with water in response to a low level signal emanating from the low level detector N ₁ (or N ₁ '),
- interrupting the filling of the dilution tank 300 with water, and then circulating the disinfectant solution in the circulation loop 450 (or 450') in response to a high level signal emanating from the high level detector N ₂ (or N ₂ '), or
- switching on the measuring device 400 to begin measuring the free chlorine content of the contents of the dilution tank 300, in response to an intermediate level signal emanating from the intermediate level detector N ₃ (or N ₃ ') .

In practice, for filling the dilution tank 300 with water, the low level detector N ₁ (N ₁ ') detects that the level of water or disinfectant solution in the dilution tank 300 is equal to or less than one predetermined minimum level, it produces a low level signal that the control unit 600 receives. This then commands the solenoid valve 440 (or 441) to open the water supply circuit 420 to allow the supply of water to the dilution tank 300. In the particular case of the solenoid valve 441, the control unit 600 will order the latter to open channels 441a and 441b and to close channel 441c.

With regard to the interruption of filling and the circulation of the disinfectant solution in the circulation loop, when the high level detector N ₂ (or N ₂ ') detects that the level of water or disinfectant solution in the dilution tank is equal to or greater than a predetermined maximum level, it sends a high level signal to the control unit 600. This then commands the solenoid valve 440 (or 441) to close and the pump 430 to start sucking part of the disinfectant solution out of the dilution tank 300 so that this part of disinfectant solution circulates in the circulation loop towards the water inlet 302 of the dilution tank 300.

The system according to the present invention may include forced operation and automatic operation.

With reference to Figures 10 to 12, the control unit 600 can include a user interface 601, of the type comprising buttons, allowing for example to select forced operation or automatic operation, to adjust the threshold values in particular of the pH and the free chlorine content, to manage the production of the disinfectant solution (use of one or more electrolysers and/or sets of electrodes). The user interface 601 can also make it possible to control, via the control unit 600, different elements of the system according to the present invention, for example,
- Switching on or off the energy source 101 supplying electric current to the set(s) of electrodes 120 of the at least one electrolyser 100, and/or
- Switching on or off at least one electrolyzer 100, and/or
- Switching the measuring device 400 on or off, and/or
- The opening or closing of the solenoid valve 440, and/or
- Starting or stopping the pump 430, and/or
- switching the pH regulation device on or off, and/or
- The reversal of the polarity of the electrodes of the set(s) of electrodes 120 and, where appropriate, the pause time between each polarity reversal.

The user interface 601 can also allow the user to obtain information sequentially on the operating state of the system, on the production of the disinfectant solution containing the hypochlorous acid, and in particular, on the measured pH value. by the pH probe 413, on the value of the free chlorine level measured by the sensor 411, or on the operating times of the electrolyzer(s) 100 recorded by the control unit 600 over time.

During forced operation, the control unit 600 only orders the interruption of the electrical current supply to the electrolyzer(s) 100 when the desired free chlorine content for the disinfectant solution is reached or exceeded.

During automatic operation, the control unit 600 manages the production of the disinfectant solution containing hypochlorous acid, for example, by authorizing or prohibiting the supply of electrical current to one or more electrolysers 100, when there are several, and/or the supply of electric current to one or more electrodes 120, when there are several per electrolyzer 100.

The control unit 600 can continuously monitor the production of the disinfectant solution in the dilution tank and order the shutdown of the electrolyzer(s) 100, when there are several by cutting off the electrical current supply to the(s) corresponding set(s) of electrode(s), in the case where the free chlorine content measured by the sensor 411 exceeds the value of the pre-recorded threshold.

The control unit 600 can continuously monitor the production of the disinfectant solution in the dilution tank and order the shutdown of the electrolyzer(s) 100, when there are several by cutting off the electrical current supply to the(s) corresponding set(s) of electrode(s), in the case where the pH probe has measured a pH outside the pH threshold range previously recorded and where the control unit 600 has detected an anomaly in the operation of the the pH regulating device, for example the latter is no longer capable or available to inject the pH correction agent to bring the pH back into the desired pH range.

In particular embodiments, not shown, the system according to the present invention may further comprise a remote information transmission system 603 and/or a system for storing all of the information in the system according to the invention:
- the percentage of production,
- the measured pH value of the disinfectant solution,
- the measured value of the free chlorine content of the disinfectant solution
- the values of the thresholds set, in particular for the pH and the free chlorine content,
- the operating time of the system according to the present invention, to determine when to change the at least one set of electrodes 120,
- the polarity inversion period of the at least one set of electrodes 120,
- the occurrence of each power outage.
- automatic march or forced march
- triggering diagnostics.

This information can be recorded at least three times a day over 30 days in a loop. However, it may be preferable to retain information on the diagnosis of the system according to the invention, the occurrence of power outages.

The control unit 600 is preferably provided with a screen 602 of the liquid crystal screen 82 type, or Liquid Crystal Display in English, i.e. LCD, communicating information on the operation of the system according to the invention to the user.

For further information on the control unit 600 (its characteristics and uses) one can usefully refer to patent application WO2012172118A1 in the name of the applicant.

In summary, the system according to the present invention can operate in manual and/or semi-automatic and/or automatic mode, to monitor the production of disinfectant solutions containing hypochlorous acid at the free chlorine contents desired by the user.

Also, the present invention also relates to a process for producing the disinfectant solution. This process according to the invention comprises:
- a step a) in which a system according to the present invention is provided;
- a step b) in which the dilution tank 300 and the electrolysis chamber 110 are filled with water in accordance with the present invention;
- a step c) in which an electric current is applied to the electrodes of the at least one set of electrodes 120 of the at least one electrolyser 100 to electrolyze the aqueous solution containing chloride ions in the enclosure 110 in order to produce hypochlorous acid, and in which at least part of the hypochlorous acid migrates from said enclosure 110 towards said dilution tank 300 via conduit 200, the at least part of the hypochlorous acid having migrated being diluted in the water present in said dilution tank 300 in order to form the disinfectant solution;
- a step d) in which the free chlorine content of the disinfectant solution forming in the dilution tank 300 is measured;
- a step e) in which the electrolysis is interrupted when the free chlorine content measured in step d) reaches a desired free chlorine content value for the disinfectant solution.

By desired free chlorine content value, it is necessary to understand the free chlorine content value desired or selected by the user and that the latter considers that it is sufficiently high for the user he wishes to make of the solution disinfectant containing hypochlorous acid.

The method according to the present invention may further comprise a step f) in which the free chlorine content is measured by the sensor 411 capable of measuring the free chlorine content of the disinfectant solution forming in said dilution tank.

The method according to the present invention may further comprise a step g) in which the interruption of the electrolysis provided for in step e) is taken care of by the control unit 600 adapted to compare the free chlorine content measured by the sensor 411 in step f) and a threshold value of the free chlorine content and to interrupt the electrolysis when the free chlorine content measured by the sensor 411 is equal to or greater than the threshold value of the chlorine content free. Preferably, this threshold value of the free chlorine content is set at a maximum value selected in a range of 5 ppm to 3000 ppm, in particular in a range of 10 ppm to 1500 ppm.

The method according to the present invention may further comprise a step h) in which at least one intrinsic parameter of the disinfectant solution forming in the dilution tank 300 is measured, which intrinsic parameter can be chosen from the list of parameters including the pH , temperature, conductivity, and hardness.

The method according to the present invention may further comprise a step g) in which the pH of the disinfectant solution forming in the dilution tank 300 is regulated.

Preferably, in step c) the current voltage applied to the electrodes is between 1 and 15 volts, preferably between 2 and 10 volts.

Advantageously, the disinfectant solution containing the hypochlorous acid has a pH of approximately 5.1 to approximately 6.9, preferably a pH of approximately 6.5. These pH ranges are optimal for the applications for which the disinfectant solutions produced according to the present invention are intended.

The various elements (dilution tank, electrolyzer(s), communication conduit, pipes, wiring, means of measurement (pH, free chlorine content) and regulation, control unit, etc.) of the system according to the present invention can be arranged in a compact assembly, with a small footprint, which is transportable and ready to be installed and used for the production of disinfectant solution based on hypochlorous acid.

In practice, the entire system according to the present invention is carried by a vertical support structure capable of supporting at least the dilution tank 300 and the electrolysis enclosure 110 of the at least one electrolyser 100 and ensuring the rigidity of the 'together. This vertical support structure can, for example, be of the type comprising a frame delimiting a space dedicated to the production of the disinfectant solution according to the present invention and in which are arranged:
- a first compartment mounted on the chassis and in which the at least one electrolyser 100, and where appropriate the circulation pump 430, can be arranged;
- a second compartment arranged above the first compartment and in which the dilution tank 300 can be placed, this second compartment having in its lower part, at least one lower opening, to be able to place, through this at least one lower opening , the respective communication conduit 200 of the at least one electrolyzer,
- the exterior walls of the first compartment PC1 and/or second compartment PC2 serving as support for the other elements of the system according to the present invention such as the electrical power source 101, the water supply pipe, the cable(s) electrical, and where appropriate, the control unit 600, the solenoid valve 440 (or 441), and other components/elements considered to fall within the scope of the present invention.

Of course, the invention is not limited to this form of mounting of the system herein. In particular, it is possible to provide a form of chassis comprising two opposite parallel side walls (or two pairs of opposite side uprights), an upper horizontal plate provided to support the tank 300, and a lower horizontal plate (or base or base) provided to support the at least one electrolyser 100 and where appropriate the pump 430, the upper and lower plates being fixedly connected to the opposite side walls (or to the pairs of opposite side uprights) and the upper plate having at least one lower opening, for the placement of the respective communication conduit 200 of the at least one electrolyzer.

An example of a system according to the present invention assembled in the form of a compact assembly is shown in the photograph of the .

Additionally, one or more features set forth only in one embodiment may be combined with one or more other features set forth only in another embodiment. Likewise, one or more characteristics presented only in one embodiment can be generalized to other embodiments, even if this or these characteristics are described only in combination with other characteristics.
- The electrolysis enclosure 110 or its cover 130 may be provided with a pressure gauge to monitor the pressure in this electrolysis enclosure 110,
- The dilution tank 300 can be fitted with a cover or a ceiling with an orifice for the evacuation of gas (hydrogen and, where applicable, chlorine gas)
- The electrodes of the at least one set of electrodes 120 can be solid or perforated,
- The electrolysis enclosure(s) 100 can be mounted on a base or base,
- The support structure intended to support the system according to the present invention can be equipped with rolling means such as casters in order to facilitate the movement of the entire said system.

Examples

Various production tests of a disinfectant solution containing hypochlorous acid with a free chlorine content of 250 ppm were carried out with the following operating conditions:

- Dilution tank 300 = 260 liters,
- Electrolysis chamber = 40 liters,
- Set(s) of electrodes = per set of electrodes, 7 flat plates arranged in parallel rows of alternating polarity. The plates have a dimension of 210 mm long by 55 mm wide, and are made of titanium coated with titanium oxide, ruthenium oxide and iridium oxide.
- Ambient temperature (around 25°C)
- The disinfectant solution was maintained at pH = 6.5
- The applied voltage = between 4 and 6 volts

- Current intensity = between 15 and 30 amps Number of electrolyzers Number of electrode sets Production time (in hours) Trial 1 1 1 7 to 9 Test 2 2 1 5 to 7 Trial 3 3 1 3 to 5 Test 4 1 2 5 to 7 Trial 5 2 2 3 to 4 Test 6 3 2 2 to 3

It appears from this table that for the production of a disinfectant solution containing hypochlorous acid at a given free chlorine content, the greater the number of electrolyzers and/or sets of electrodes, the greater the production duration. of said disinfectant solution is reduced.

The invention is not limited to the described embodiments alone. Furthermore, in the claims, any parenthetical reference sign shall not be construed as a limitation of the claim. Furthermore, the use of the verb “include”, “understand” or “include” and its conjugated forms does not exclude the presence of other elements or other steps than those set out in a claim. Of course, one or more features shown only in one embodiment can be combined with one or more other features shown only in another embodiment. Likewise, one or more characteristics exposed only in one embodiment can be generalized to other embodiments.

Claims (23)

System for producing a disinfectant solution containing hypochlorous acid, characterized in that it comprises:
- a dilution tank (300) dedicated to the preparation of the disinfectant solution, which tank (300) includes a water inlet (302) allowing said tank to be filled with water,
- at least one electrolyser (100) placed below the dilution tank (300), and comprising:
-- an electrolysis chamber (110) storing alkaline chloride in solid form,
-- at least one set of electrodes (120) comprising at least one anode and at least one cathode arranged in the electrolysis enclosure (110),
-- a conduit (200) putting the electrolysis enclosure (110) and the dilution tank (300) into fluid communication,
and in which:
- filling the dilution tank (300) with water causes the electrolysis enclosure (110) to be filled with water through the conduit (200) to prepare an aqueous solution containing chloride ions by dissolving part of the alkaline chloride stored in said electrolysis enclosure, and,
- the electrolysis of the aqueous solution in the enclosure (110) produces hypochlorous acid, at least part of which migrates from the electrolysis enclosure (110) towards the dilution tank (300) via the conduit (200 ), the at least part of the hypochlorous acid having migrated being diluted in the water present in the dilution tank (300) in order to form the disinfectant solution. System according to claim 1, in which the electrolysis of the aqueous solution in the electrolysis enclosure (110) of the at least one electrolyzer is adjusted to generate the formation of gas bubbles, so that said bubbles create turbulence capable of forcing the migration of at least part of the hypochlorous acid from the electrolysis enclosure (110) towards the dilution tank (301) via the conduit (200). System for producing a disinfectant solution according to claim 1 or 2, wherein the at least one electrolyzer (100) is one or two or three or more of three electrolyzers (100). System for producing a disinfectant solution according to one of claims 1 to 3, in which the at least one set of electrodes (120) is one or two or more than two sets of electrodes (120). System for producing a disinfectant solution according to one of claims 1 to 4, in which the at least one set of electrodes (120) further comprises a plurality of bipolar electrodes interposed between an anode and a cathode of the at least one set of electrodes (120). System for producing a disinfectant solution according to claim 5, wherein the at least one anode, the at least one cathode and the plurality of bipolar electrodes of the at least one set of electrodes (120) are all in the form of flat plates, parallel and regularly spaced from each other. System for producing a disinfectant solution according to one of claims 1 to 4, in which the at least one set of electrodes (120) comprises a plurality of anodes and a plurality of cathodes, which pluralities of anodes and cathodes are in the form of flat plates arranged in parallel rows of alternating polarity. System for producing a disinfectant solution according to one of claims 1 to 7, in which the electrolysis enclosure (110) of the at least one electrolyser (100) has a capacity of at least 10 liters. System for producing a disinfectant solution according to one of claims 1 to 8, in which the dilution tank (300) comprises means for breaking the bubbles of chlorine gas which may come from the electrolysis enclosure (110) of the at least one electrolyser (100) in order to promote the dissolution of the chlorine gas in the water, said means for breaking said bubbles of chlorine gas being arranged at the bottom of the dilution tank (300) at least opposite the conduit ( 200) placing said electrolysis enclosure (110) and the dilution tank (300) in fluid communication. System for producing a disinfectant solution according to claim 9, in which the means for breaking the gas bubbles consist of at least one flat plate and having perforations whose diameter is sufficient to reduce the size of the gas bubbles to dimensions favoring the dissolution of chlorine in water. System for producing a disinfectant solution according to claim 10, in which the perforations of the at least one plate have a diameter of less than 5 mm, preferably less than 1 mm. System for producing a disinfectant solution according to claim 11 or 12, in which when the means for breaking the gas bubbles consist of several flat and perforated plates, which plates are superimposed such that the perforations of a plate are offset from the perforations of another plate adjacent to it. System for producing a disinfectant solution according to one of claims 1 to 12, further comprising a measuring device (400) comprising:
- a sensor (411) adapted to measure the free chlorine content in the disinfectant solution forming in the dilution tank (300),
- a display (412) adapted to display the free chlorine content measured by the sensor (411). System for producing a disinfectant solution according to one of claims 1 to 13, further comprising regulation means for regulating the pH of the disinfectant solution forming in the dilution tank (300). System for producing a disinfectant solution according to one of Claim 13, further comprising a control unit (600) operatively connected to the device for measuring (400) the free chlorine content, which control unit (600) is adapted to compare the free chlorine content measured by the sensor (411) and a threshold value of the free chlorine content and to interrupt the electrolysis when the free chlorine content measured by the sensor (411) is equal to or greater than the threshold value of free chlorine content. System according to claim 15, in which the threshold value of the free chlorine content is set at a maximum value selected in a range of 5 ppm to 3000 ppm, in particular in a range of 10 ppm to 1500 ppm. System for producing a disinfectant solution according to one of claims 1 to 16, in which the water inlet (302) of the dilution tank (300) is connected to a water source (S) by a water supply circuit (420) comprising, in the direction of the dilution tank (300), a solenoid valve (440) and a circulation pump (430). System for producing a disinfectant solution according to claim 17, in which the dilution tank (300) has a sampling outlet (307) for the disinfectant solution, which sampling outlet (307) is connected to a tap (421) provided on the water supply circuit (420) between the solenoid valve (440) and the circulation pump (430) so that the sampling line (410) forms with the pump (430) and the part of the circuit water supply (420) located after the pump (430) a recirculation loop (450) configured to circulate the disinfectant solution from the sampling outlet (307) to the water inlet (302). System for producing a disinfectant solution according to claim 18 in combination with claim 13, in which the free chlorine measuring device (400) is placed on the recirculation loop (450), in particular on the sampling line ( 410), so as to allow continuous measurements to be carried out on the disinfectant solution. Process for producing a disinfectant solution containing hypochlorous acid, comprising:
a) a step of providing a system according to one of the preceding claims;
b) a step of filling the dilution tank (300) of said system with water, and in which filling the dilution tank (300) with water results in filling the electrolysis enclosure (110) of the at least one electrolyzer (100) of said system through the conduit (200) placing said electrolysis enclosure (110) and said dilution tank (300) in fluid communication, in order to prepare an aqueous solution containing chloride ions by dissolution of part of the alkaline chloride stored in said electrolysis chamber (110);
c) a step of applying an electric current to the electrodes of the at least one set of electrodes (120) of said at least one electrolyzer (100) to electrolyze the aqueous solution containing chloride ions in said enclosure (110) in order to produce hypochlorous acid, and in which at least part of the hypochlorous acid migrates from said enclosure (110) towards said dilution tank (300) via said conduit (200), the at least part of the hypochlorous acid having migrated is diluted in the water present in said dilution tank (300) in order to form the disinfectant solution;
d) a step of measuring the free chlorine content of the disinfectant solution forming in said dilution tank (300);
e) a step of interrupting the electrolysis when the free chlorine content measured in step d) reaches a desired free chlorine content value for the disinfectant solution;
f) optionally, a step of measuring the free chlorine content by a sensor (411) capable of measuring the free chlorine content of the disinfectant solution forming in said dilution tank;
g) optionally, the interruption of the electrolysis provided for in step e) is taken care of by a control unit (600) adapted to compare the free chlorine content measured by the sensor (411) in step f ) and a threshold value of the free chlorine content and to interrupt the electrolysis when the free chlorine content measured by the sensor (411) is equal to or greater than the threshold value of the free chlorine content;
h) optionally, a step of measuring at least one intrinsic parameter of the disinfectant solution forming in the dilution tank (300), which intrinsic parameter is chosen from the list of parameters including pH, temperature, conductivity, and hardness;
i) optionally, a step of regulating the pH of the disinfectant solution forming in the dilution tank (300). Method according to claim 20, wherein in step c) the current voltage applied to the electrodes is between 1 and 15 volts, preferably between 2 and 10 volts. A method according to claim 20 or 21, wherein the disinfectant solution containing the hypochlorous acid has a pH of about 5.1 to about 6.9, preferably a pH of about 6.5. Method according to one of claims 19 to 21, in which in optional step g) the threshold value of the free chlorine content is set at a maximum value selected in a range from 5 ppm to 3000 ppm, in particular in a range from 10 ppm to 1500 ppm.