Electrolytic cell for producing hypochlorous acid

Abstract

An electrolytic cell for producing hypochlorous acid and sodium hydroxide as separate product streams from brine is described. The electrolytic cell includes: an electrolysis chamber including an anode and a cathode; an electrical connection to each of the anode and the cathode; a brine inlet into the electrolysis chamber for supplying a brine solution into the electrolysis chamber; a first liquid outlet from the electrolysis chamber proximate the anode; a second liquid outlet from the electrolysis chamber near the cathode; at least one pump arranged to draw liquid from the electrolysis chamber through the first liquid outlet at a first flow rate and through the second liquid outlet at a second flow rate. The pools can produce hypochlorous acid for on-site use, e.g., as a cleaning product for home or commercial or industrial sites.

Description

Technical Field

[0001] The present invention relates to an electrolytic cell for producing hypochlorous acid as a product. The present invention also relates to a method for producing hypochlorous acid using such a cell, as well as a hypochlorous acid generator and a household cleaning product dispenser containing such a cell. Background Art

[0002] Hypochlorous acid, HOCl, can be produced by electrolyzing brine (concentrated sodium chloride solution). During the electrolysis process, chloride ions are oxidized at the anode to form chlorine, and water molecules are reduced at the cathode to form sodium hydroxide and hydrogen. The chlorine formed at the anode reacts with water to form hypochlorous acid.

[0003] In the commercial production of sodium hypochlorite (household bleach) by electrolysis, hypochlorous acid produced at the anode reacts with sodium hydroxide produced at the cathode to form the sodium hypochlorite product, NaOCl. This process is carried out on a million-ton scale and is known as the chlor-alkali process.

[0004] The advantage of sodium hypochlorite is that it is relatively stable and can be stored for long periods of time without degradation or loss of bactericidal activity.

[0005] Hypochlorous acid has approximately 100 times the germicidal activity of sodium hypochlorite. Therefore, only a small amount of hypochlorous acid is needed to achieve a comparable germicidal effect as sodium hypochlorite bleach, and a reduced contact time with the surface is required to achieve an effective germicidal rate. This is a significant advantage for household cleaning products that are typically "quick-applied," where the consumer only briefly applies the product to the surface before rinsing. Unfortunately, hypochlorous acid rapidly degrades during storage, thereby losing its germicidal activity. Therefore, it is not possible to commercially prepare hypochlorous acid for consumer use as a substitute for ordinary bleach.

[0006] There is a need for products and processes that allow consumers to take advantage of the enhanced germicidal activity of hypochlorous acid to provide improved household cleaning products. There is also a need for more convenient and versatile household devices that provide consumers with the choice of cleaning products tailored to the intended application. Summary of the invention

[0007] A first aspect of the invention is an electrolytic cell for producing hypochlorous acid and sodium hydroxide as separate product streams from brine, the electrolytic cell comprising:

[0008] an electrolysis chamber, including an anode and a cathode;

[0009] an electrical connection to each of the anode and the cathode;

[0010] a brine inlet into the electrolysis chamber for supplying brine solution into the electrolysis chamber;

[0011] a first liquid outlet from the electrolysis chamber proximate the anode;

[0012] a second liquid outlet from the electrolysis chamber proximate the cathode; and

[0013] at least one pump arranged to draw liquid from the electrolysis chamber at a first flow rate through the first liquid outlet and at a second flow rate through the second liquid outlet;

[0014] in:

[0015] (a) the first flow rate and the second flow rate are variable relative to each other; or

[0016] (b) The first flow rate and the second flow rate are fixed relative to each other at a predetermined flow rate difference.

[0017] The pool can generate hypochlorous acid for on-site use, for example as a cleaning product in the home or at a commercial or industrial site. In this way, there is no need to store hypochlorous acid for long periods of time and the product can be used immediately or stored briefly before use, thus avoiding loss of germicidal activity. In addition, the pool provides the user with a convenient device to generate a more effective germicidal disinfectant product on demand than ordinary bleach, using a freely available salt solution prepared by mixing ordinary table salt into water.

[0018] Not only does the cell produce hypochlorous acid from the first liquid outlet, but the presence of a separate second liquid outlet near the cathode provides a source of sodium hydroxide solution that has a separate use as a cleaning product, which is particularly effective as a degreaser (sodium hydroxide is a common ingredient in oven cleaners). Thus, the cell dispenses two separate products with different cleaning and sanitizing applications, providing a convenient and versatile source of on-demand cleaning products.

[0019] Surprisingly, the inventors have found that by providing variable first and second flow rates relative to each other, the properties of the product from the pool can be customized according to the needs of the user and provide improvements in pool efficiency. By adjusting the relative flow rates, it has been found that the pH of the product flowing out of the first liquid outlet of the pool can be customized. In this way, the solution leaving the first liquid outlet can have properties customized for the desired application. For example, a hypochlorous acid solution with a very low pH value can be used as a descaling agent. A slight increase in the pH value of the solution will make the solution more suitable for use as a general disinfectant, such as for disinfecting floors and work surfaces. A further increase in the pH value to the neutral range will provide a solution more suitable for disinfecting delicate surfaces.

[0020] Similarly, by providing first and second flow rates that are fixed relative to each other but have a predetermined difference in flow rate, a manufacturer or end user can select a fixed flow deviation to suit the properties of the product flowing from the pool and provide consistent product production.

[0021] Thus, the present invention provides a device that allows a user to precisely control the properties of the resulting product, which can be tailored to the specific desired cleaning or disinfecting application.

[0022] A second aspect of the present invention is a hypochlorous acid generator, comprising the electrolytic cell according to the first aspect, and further comprising:

[0023] one or more of a saline reservoir and a saline supply conduit;

[0024] Hypochlorous acid storage unit;

[0025] Sodium hydroxide storage unit;

[0026] a power source; and

[0027] Product dispensing device.

[0028] Such a generator provides a means for producing hypochlorous acid on demand, for example in a home or workplace, from a freely available salt solution precursor stored in a salt water reservoir. This provides a convenient and versatile means for dispensing hypochlorous acid as a disinfectant as well as other useful products such as sodium hydroxide for use as a degreasing agent.

[0029] A third aspect of the invention provides a method for producing hypochlorous acid using a cell according to the first aspect, the method comprising:

[0030] allowing brine to enter the electrolysis chamber through a brine inlet;

[0031] applying a voltage across the electrical connections of the anode and cathode to electrolyze the salt water;

[0032] drawing a first product stream from a first liquid outlet at a first flow rate, the first product stream comprising hypochlorous acid; and

[0033] drawing a second product stream from a second liquid outlet at a second flow rate, the second product stream comprising sodium hydroxide;

[0034] The concentration of hypochlorous acid in the first product stream is higher than the concentration of hypochlorous acid in the second product stream.

[0035] The method of the third aspect provides a convenient and versatile method to produce hypochlorous acid as a bactericide (disinfectant) as well as other useful products, such as sodium hydroxide, which is used as a degreasing agent.

[0036] A fourth aspect of the present invention provides a household cleaning product dispenser comprising an electrolytic cell according to the first aspect. In this way, consumers can dispense the required cleaning products on demand, thereby eliminating the need to purchase cleaning products for home or workplace use separately. In addition, hypochlorous acid has superior bactericidal activity relative to sodium hypochlorite bleach, which can also be enjoyed by ordinary consumers because hypochlorous acid is generated on site and does not require long-term storage of unstable hypochlorous acid.

[0037] The preferred and / or optional features of the present invention will now be described. Unless the context otherwise requires, any aspect of the present invention may be combined with any other aspect of the present invention. Unless the context otherwise requires, any preferred and / or optional features of any aspect may be combined with any aspect of the present invention individually or in combination.

[0038] The term "electrolytic cell" refers to an arrangement of anodes and cathodes separated by an electrolyte, the electrolytic cell being suitable for use as a salt water electrolyser when an appropriate voltage is applied between the anodes and cathodes.

[0039] "Hypochlorous acid" refers to the compound HOCl, or a partially or completely dissociated form thereof in solution, which can dissociate into ions H + and ClO - exists in the form of.

[0040] "Sodium hydroxide" means the compound NaOH, or a partially or completely dissociated form thereof in solution, which can be used as the dissociated ion Na + and OH - exists in the form of.

[0041] The term "electrolysis chamber" refers to the area or volume within an electrolyzer containing the anode and cathode, wherein decomposition of chemical species at the anode and cathode occurs when an appropriate voltage is applied between the anode and cathode.

[0042] The term "brine" refers to an aqueous solution of sodium chloride (NaCl) of any concentration.

[0043] A first aspect of the invention is an electrolytic cell for producing hypochlorous acid and sodium hydroxide as separate product streams from brine as defined in claim 1.

[0044] In some embodiments, the electrolytic cell is used to produce hypochlorous acid and sodium hydroxide as separate products. In some embodiments, the electrolytic cell is used to produce a first product comprising a mixture of hypochlorous acid and hydrochloric acid, and a second separate product comprising sodium hydroxide.

[0045] In some embodiments, the at least one pump comprises:

[0046] a first pump arranged to draw liquid from the electrolysis chamber through the first liquid outlet at a first flow rate; and

[0047] A second pump is arranged to draw liquid from the electrolysis chamber through the second liquid outlet at a second flow rate.

[0048] Providing separate first and second pumps provides a simple and reliable method to control the flow rates at the first and second liquid outlets from the pool. However, those skilled in the art will recognize that there may be alternative methods to achieve the first and second flow rates without the need for two separate pumps. For example, a single pump may be used with two separate valves, wherein the operation of the valves may be controlled independently of each other to vary the first and second flow rates.

[0049] The at least one pump preferably comprises one or more peristaltic pumps. In some embodiments, the at least one pump preferably consists of one or more peristaltic pumps. In some embodiments, the at least one pump consists of two peristaltic pumps, a first peristaltic pump arranged to pump liquid from the electrolysis chamber through the first liquid outlet at a first flow rate, and a second peristaltic pump arranged to pump liquid from the electrolysis chamber through the second liquid outlet at a second flow rate. One or both of the first and second peristaltic pumps are controllable to vary the flow rate.

[0050] The at least one pump may be connected to one or more pump motors.

[0051] In some embodiments, one or more pump motors are powered by a power source (eg, a battery) via a pulse width modulation (PWM) module.

[0052] The peristaltic pump may include a peristaltic pump head connected to a peristaltic pump motor. In some embodiments, the first and second peristaltic pumps are each connected to the same motor and controlled by the same motor. In some embodiments, the first and second peristaltic pumps are connected to different motors and controlled by different motors. Each peristaltic pump motor may be powered by a battery via a pulse width modulation (PWM) module.

[0053] In some embodiments, the pool does not include any pumps at its upstream position. In some embodiments, the pool does not include any pumps at the upstream position of the first and second liquid outlets. In other words, the flow of liquid through the pool is achieved entirely by using one or more downstream pumps (preferably two separate downstream pumps) to "pull" the liquid through the pool and out of the liquid outlet, without any pumps that "push" the liquid through the pool from upstream. It has been found that this arrangement can provide more precise control of the liquid through the pool and is conducive to achieving a flow imbalance between the first and second liquid outlets. By "pulling" the liquid from each outlet individually without any "pushing", the flow rate of the leaching outlet can be fine-tuned, thereby fine-tuning the composition of the electrolysis product leaving the pool.

[0054] In addition, bubbles can be generated in the cell during the electrolysis process, which can interfere with the electrolysis process, resulting in undesirable changes in the pH value of the product and / or the concentration of hypochlorous acid in the product. By "pulling" the solution in a manner using a downstream pump (e.g., a downstream peristaltic pump), bubbles can be removed from the cell more effectively and efficiently, which is not possible when using upstream pumping. This is particularly important at the second liquid outlet, because the cathode generally produces a higher concentration of insoluble gas during the electrolysis process.

[0055] In the electrolytic cell, a first liquid outlet from the electrolysis chamber is near the anode and a second liquid outlet from the electrolysis chamber is near the cathode. In this way, the products dispensed from the first and second liquid outlets are specific products resulting from electrolysis at the specific electrodes near that outlet and are distinct from one another because the electrolysis products at the anode are drawn off at the first liquid outlet and the electrolysis products at the cathode are drawn off at the second liquid outlet before those products are able to mix with one another to any significant extent within the cell.

[0056] The first liquid outlet of the electrolysis chamber is near the anode. In other words, the first liquid outlet is adapted (eg, positioned) to draw liquid primarily from near the anode, or adapted (eg, positioned) to draw liquid preferentially from an area near the anode relative to an area near the cathode.

[0057] In this way, the first liquid outlet serves to distribute the electrolysis product formed at the anode (ie, mainly the hypochlorous acid solution).

[0058] In some embodiments, the first liquid outlet from the electrolysis chamber is located closer to at least a portion of the anode than to any portion of the cathode. In this way, the physical location of the first liquid outlet within the cell provides preferential extraction of the product from near the anode.

[0059] The second liquid outlet of the electrolysis chamber is near the cathode. In other words, the first and second outlets are configured (e.g., positioned) to draw liquid primarily from near the cathode, or configured (e.g., positioned) to draw liquid preferentially from an area near the cathode relative to an area near the anode.

[0060] In this way, the second liquid outlet serves to distribute the electrolysis product (mainly sodium hydroxide solution) formed at the cathode.

[0061] In some embodiments, the second liquid outlet from the electrolysis chamber is located closer to at least a portion of the cathode than to any portion of the anode. In this way, the physical location of the second liquid outlet within the cell provides preferential extraction of product near the cathode.

[0062] The first and second liquid outlets may each be located within an interior wall of an electrolysis chamber that is otherwise liquid impermeable (except for the brine inlet) such that the only permitted passage of liquid out of the cell is through the first or second liquid outlet.

[0063] The area of ​​the first liquid outlet may be at least 1.5 mm 2 The area of ​​the first liquid outlet can be up to 10.0 mm 2 In some embodiments, the area of ​​the first liquid outlet is 1.5 to 10.0 mm 2 .

[0064] In some embodiments, the inner wall of the electrolysis chamber adjacent to the first liquid outlet is angled or funneled toward the first liquid outlet. This facilitates the flow of liquid toward and into the first liquid outlet, thereby establishing flow conditions within the cell, further preventing mixing of the anodic electrolysis product with the cathodic electrolysis product. This arrangement also helps to effectively remove cell bubbles from the cell.

[0065] In some embodiments, a portion of the inner wall of the electrolysis chamber adjacent to the first liquid outlet is angled or funneled toward the first liquid outlet, wherein the length of the angled or funneled portion of the inner wall is at least twice the diameter of the first liquid outlet, such as at least three or four times the diameter of the first liquid outlet. Providing such an angled or funneled section of the wall can further improve flow to the outlet.

[0066] In some embodiments, the inner wall of the electrolysis chamber adjacent to the second liquid outlet is angled or funneled toward the second liquid outlet. This facilitates the flow of liquid toward and into the second liquid outlet, thereby establishing flow conditions within the cell, further preventing mixing of the anode electrolysis product with the cathode electrolysis product. This arrangement also helps to effectively remove bubbles from the cell.

[0067] In some embodiments, a portion of the inner wall of the electrolysis chamber adjacent to the second liquid outlet is angled or funneled toward the second liquid outlet, wherein the length of the angled or funneled portion of the inner wall is at least twice the diameter of the second liquid outlet, such as at least three or four times the diameter of the second liquid outlet. Providing such a section of angled or funneled wall may provide further improvement in flow to the outlet.

[0068] In some embodiments, each of the anode and cathode is liquid permeable. In this way, the anode and cathode are adapted to allow liquid to flow through them, which can facilitate the operation of the cell and provide improved flow of brine and electrolysis products within the electrolysis chamber.

[0069] In some embodiments, each of the anode and cathode is a liquid permeable mesh.

[0070] In other embodiments, each of the anode and cathode can be liquid-impermeable. In such embodiments, a means for allowing liquid to pass through or around the electrodes will be provided. For example, there may be gaps or channels around the electrodes to allow liquid to pass through the electrodes and flow to an appropriate liquid outlet.

[0071] It is desirable to provide a lightweight, handheld hypochlorous acid generating device comprising an electrolytic cell of the first aspect. However, in order to achieve this and ensure sufficiently long operating time, the power consumption of the device must be kept at a low level. In some embodiments, the cell is suitable for producing a useful amount of hypochlorous acid at low power. To achieve this, in some embodiments, the distance between the anode and the cathode is reduced. For example, in some embodiments, the spacing between the anode and the cathode is less than 3.0 mm, for example, less than 2.0 mm. Providing a tighter anode and cathode spacing reduces the internal resistance of the cell, thereby reducing power requirements. Alternatively or additionally, in some embodiments, the sodium chloride concentration in the brine solution supplied to the cell is increased, as explained in more detail below. A higher concentration of sodium chloride reduces the internal resistance of the cell during the electrolysis process, thereby reducing power requirements. Alternatively or additionally, in some embodiments, the properties of the anode and / or cathode can be adjusted to reduce the power consumption of the cell. For example, as described below, the anode and cathode can include a catalyst, such as an IrO2 / RuO2 mixed metal oxide catalyst, to increase the electrolysis rate, thereby allowing a given concentration of hypochlorous acid to be produced at a lower power requirement. One or more of these modifications may be employed within a cell to reduce power consumption and ensure adequate run time when using a battery power source.

[0072] In some embodiments, one or both of the anode and cathode include a metal substrate and a noble metal oxide catalyst supported on the substrate. In some embodiments, one or both of the anode and cathode include a transition metal substrate and a platinum group metal oxide catalyst supported on the substrate.

[0073] In some embodiments, the metal substrate comprises titanium or platinum, and the noble metal oxide catalyst comprises an IrO2 / RuO2 mixed metal oxide catalyst. In some embodiments, the metal substrate comprises titanium, and the noble metal oxide catalyst comprises an IrO2 / RuO2 mixed metal oxide catalyst.

[0074] In some embodiments, the anode and cathode each comprise a catalyst selected from IrO2, RuO2, Pt, boron-doped diamond (BDD), and mixtures thereof. In some embodiments, the anode and cathode each comprise a catalyst selected from IrO2, RuO2, Pt, and mixtures thereof.

[0075] In some embodiments, the catalyst supported on the anode is the same as the catalyst supported on the cathode. This facilitates polarity switching, after which the cathode will become the anode and vice versa.

[0076] The anode and cathode can each include a substantially planar film or sheet. In some embodiments, the film or sheet defines a plurality of pores for allowing liquid to flow from one side of the sheet to the other through the plane of the sheet. In some embodiments, each of the anode and cathode has a porosity of 80% to 40%, wherein the porosity is defined as the total area of ​​the pores as a percentage of the total area of ​​the sheet. In some embodiments, the porosity of each of the anode and cathode is 75% to 40%, such as 73% to 45%.

[0077] In some embodiments, the anode comprises a planar sheet having a thickness of 0.15 mm to 1.50 mm.

[0078] In some embodiments, the cathode comprises a planar sheet having a thickness of 0.15 mm to 1.50 mm.

[0079] Each of the anode and cathode may independently have a length of at least 20 mm, such as at least 25 mm. Each of the anode and cathode may independently have a length of up to 120 mm, such as up to 100 mm.

[0080] Each of the anode and cathode may independently have a width of at least 15 mm, such as at least 18 mm. Each of the anode and cathode may independently have a width of up to 80 mm, such as up to 75 mm.

[0081] In some embodiments, the anode and cathode are each independently a planar sheet having a length of 25 to 100 mm and a width of 18 to 75 mm. In some embodiments, the anode and cathode are each independently a planar sheet having a length of 30 to 100 mm and a width of 20 to 75 mm.

[0082] In some embodiments, the anode and cathode are each planar sheets and are substantially parallel to each other within the cell. The spacing between the anode and cathode may be 1.5 mm to 5 mm.

[0083] In some embodiments, the anode and the first liquid outlet are arranged so that at least a portion of the liquid flowing from the brine inlet to the first liquid outlet must flow through the anode, such as through one or more holes in the porous anode. This ensures that at least a portion of the liquid entering the cell is directed toward and ultimately through the anode, thereby promoting oxidation of chloride ions at the anode.

[0084] In some embodiments, the cathode and the second liquid outlet are arranged so that at least a portion of the liquid flowing from the brine inlet to the second liquid outlet must flow through the cathode, such as through one or more holes in the porous cathode. This ensures that at least a portion of the liquid entering the cell is directed toward and ultimately through the cathode, thereby promoting water reduction at the anode.

[0085] In some embodiments, the anode is a porous anode that spans the entire electrolysis chamber such that liquid must flow through the anode to reach the first liquid outlet.

[0086] In some embodiments, the cathode is a porous cathode that spans the entire electrolysis chamber so that the liquid must flow through the cathode to reach the second liquid outlet.

[0087] In some embodiments, the cell includes a housing defining an electrolysis chamber and containing an anode and a cathode.

[0088] In some embodiments, the housing includes an opening in fluid communication with the brine inlet and the electrolysis chamber such that when the housing is at least partially submerged in the brine reservoir, brine from the reservoir enters the housing through the opening and is drawn through the cell by operation of the at least one pump to draw liquid from the electrolysis chamber.

[0089] In this manner, a pool may be used with an "open" salt water reservoir simply by placing the pool into the salt water reservoir such that the housing is at least partially submerged in the salt water reservoir (i.e., such that the opening in the housing is submerged in the reservoir). This eliminates the need for a tube or pipe for conveying salt water from the salt water reservoir to the pool, thereby providing a device that is more straightforward to operate and easier for the user to maintain. The consumer simply places the pool housing into the salt water reservoir to place the pool in operation, and can easily clean the housing opening when necessary. The user does not need to monitor the condition of any salt water pipes or replace such pipes after failure or breakage. In addition, the risk of salt water leaking from the device may be reduced or eliminated.

[0090] In some embodiments, the housing includes a base that includes a flat outer surface such that the housing can be self-supporting when placed on a surface on which the flat base is placed. For example, the housing can be self-supporting when it is located within a saline reservoir and rests on the floor of the reservoir. In this way, when the housing is placed on a surface, such as within a saline reservoir, it can maintain a stable position for a long time.

[0091] The base may occupy a portion of the housing opposite the first liquid outlet, the second liquid outlet, the first electrical connection, and the second electrical connection. In this manner, when the housing is placed at its base within the saline reservoir, the first liquid outlet, the second liquid outlet, the first electrical connection, and the second electrical connection are all located outside the reservoir and the upper portion of the housing. This allows product to be extracted directly from the outlet while ensuring that the first electrical connection and the second electrical connection do not come into contact with the saline reservoir, thereby avoiding causing a short circuit or damaging the pool.

[0092] In some embodiments, the cell includes a porous diaphragm disposed between the anode and cathode. It has been found that, although the presence of such a diaphragm is not essential for the function of the cell, it further prevents mixing of electrolysis products within the cell, thereby facilitating the generation of different products at the first liquid outlet and the second liquid outlet. In addition, the diaphragm can also reduce the diffusion of gases within the cell, such as the diffusion of hydrogen from the cathode to the anode. The diffusion of gases can push more NaOH from the cathode side to the anode side, thereby raising the pH value to a level that is not conducive to the generation of HOCl as a chlorine species at the anode.

[0093] In some embodiments, the septum comprises a woven cloth material.

[0094] In some embodiments, the diaphragm includes a non-hydrophobic or hydrophilic material. In some cases, this may help improve the performance of the diaphragm in the pool. In some embodiments, the diaphragm does not contain PTFE. The presence of a hydrophobic material such as PTFE in the diaphragm can reduce the water permeability of the diaphragm and affect the pool performance.

[0095] In some embodiments, the diaphragm is positioned in contact with the cathode. The diaphragm can be connected to the cathode, such as clamped to the cathode. In some embodiments, the diaphragm is positioned in contact with an electrode that acts as a cathode during normal operation of the cell (i.e., during a product generation cycle). In a cleaning cycle after polarity reversal, this electrode will become an anode, however, when such a cleaning cycle is short relative to the duration of the product generation cycle, it can be helpful to position the diaphragm in contact with an electrode that acts as a cathode during normal operation of the cell.

[0096] In some embodiments, the electrolytic cell does not include any diaphragm structure between the anode and cathode. Although the presence of a diaphragm can provide some benefits as described above, it may also be desirable to actively omit such a diaphragm from the cell design. The locations of the first liquid outlet and the second liquid outlet and the flow rates selected at these outlets can provide the necessary spacing of the anode and cathode electrolysis products separately and facilitate the generation of different products at the first liquid outlet and the second liquid outlet. Since there is no diaphragm in the cell, a simple and cost-effective cell design can be achieved, reducing maintenance requirements and including fewer parts that may be prone to failure.

[0097] The first flow rate at the first liquid outlet and the second flow rate at the second liquid outlet can be varied relative to each other. In other words, the difference in flow rates at the first and second liquid outlets can be variable. In other words, when the first flow rate is F1 and the second flow rate is F2, the magnitude of the parameter (F2–F1) can be variable. This enables the user of the pool to customize the composition of the product, for example to suit a desired cleaning application. This can be achieved by varying the flow rate at one liquid outlet while keeping the flow rate at the other liquid outlet fixed. Alternatively, the flow rates at the two liquid outlets can be varied independently.

[0098] In some embodiments, the flow rate at the first liquid outlet near the anode (first flow rate) is fixed, while the flow rate at the second liquid outlet near the cathode (second flow rate) is variable. In other words, the cell can be configured to provide a fixed flow rate flowing out of the first liquid outlet.

[0099] In some embodiments, the pool is configured to provide a higher liquid flow rate from the second liquid outlet than the first liquid outlet. In some embodiments, the pool is configured so that the liquid flow rate from the second liquid outlet cannot be lower than the flow rate of the liquid from the first liquid outlet. For example, one or more pumps or their associated control systems can be adapted to prevent a user from reducing the second flow rate to less than the first flow rate.

[0100] In some embodiments, the pool is configured to provide a fixed first flow rate F1 at the first liquid outlet and a variable second flow rate F2 at the second liquid outlet, wherein the second flow rate F2 is adjustable to change the composition of the first product flow drawn from the first liquid outlet, wherein F2>F1 both before and after the adjustment.

[0101] In some embodiments, the cell is configured such that F2 / F1 takes a value in the range of 1.1 to 2.0, such as from 1.1 to 1.5, or from 1.2 to 1.4.

[0102] In some embodiments, the pool is configured such that the first flow rate F1 is fixed at a value of 2 to 30 mL / min, and the second flow rate F2 can be adjusted from a first value in the range of 5 to 60 mL / min to a second value in the range of 5 to 60 mL / min that is different from the first value, wherein the first value and the second value of the second flow rate F2 are both 1.1 to 2.0 times greater than F1, for example, from 1.1 to 1.5 times, or from 1.2 to 1.4 times.

[0103] It has been found that a higher liquid flow rate from the second liquid outlet (ie, from near the cathode) provides an anode-cathode flow imbalance which helps achieve a suitable pH within the cell which favors the production of hypochlorous acid rather than other less useful products, such as sodium hypochlorite.

[0104] In order to ensure that the hypochlorous acid solution produced by the pool is safe and compliant with regulations, the pH of the solution must be within a certain range. In order to ensure that the pH of the hypochlorous acid product from the first liquid outlet is less than 7, the sodium hydroxide product is removed from the pool through the second liquid outlet. The flow imbalance between the first and second liquid outlets can be set to a level that produces a product solution of the desired pH value. The greater the flow rate of the second liquid outlet relative to the first liquid outlet, the greater the amount of sodium hydroxide removed, thereby reducing the pH of the first liquid outlet product. The NaOH removed from the second liquid outlet can itself be used as a cleaning product, or can simply be disposed of.

[0105] On the other hand, it is undesirable if the pH of the hypochlorous acid product solution exiting the first liquid outlet is very low, firstly from a safety perspective and secondly because it favors the formation of chlorine at the anode. To mitigate this and ensure that the pH is above this level, the removal of hydrogen bubbles from the cell can be controlled by controlling the flow rates of the first and second liquid outlets. For example, the reintroduction of NaOH into the solution within the cell can be controlled by reducing the flow rate at the second liquid outlet to allow the hydrogen bubbles to remain within the cell.

[0106] In some embodiments, the anode divides the electrolysis chamber into an inlet chamber located on a first side of the anode and adjacent to the cathode and an anode collecting chamber located on a second side of the anode, wherein the first liquid outlet is located in the anode collecting chamber; so that when in use, the liquid flows from the brine inlet into the inlet chamber, then passes through the anode into the anode collecting chamber, and then flows out from the first liquid outlet.

[0107] In some embodiments, the cathode divides the electrolysis chamber into a cathode collecting chamber located on a first side of the cathode and adjacent to an inlet chamber of the anode, and a cathode collecting chamber located on a second side of the cathode, wherein the second liquid outlet is located in the cathode collecting chamber; so that when in use, liquid flows from the brine inlet into the inlet chamber, then enters the cathode collecting chamber through the cathode, and then flows out from the second liquid outlet.

[0108] In some embodiments, the first flow rate and the second flow rate are fixed relative to each other at a predetermined flow rate difference. In some embodiments, the predetermined flow rate difference provides a higher HOCl concentration at the first liquid outlet than can be achieved at other flow rate differences.

[0109] In some embodiments, the first flow rate is F1, the second flow rate is F2, and F2>F1. It has been observed that the second flow rate greater than the first flow rate provides more optimal conditions for HOCl generation.

[0110] In some embodiments, the first flow rate is F1, the second flow rate is F2, and F2 / F1 is in the range of 1.1 to 2.0, such as 1.1 to 1.5, or 1.2 to 1.4. It has been found that such flow rate differences can provide optimal pH and HOCl generation.

[0111] A second aspect of the present invention is a hypochlorous acid generator, comprising the electrolytic cell according to the first aspect, and further comprising:

[0112] one or more of a saline reservoir and a saline supply conduit;

[0113] Hypochlorous acid storage unit;

[0114] Sodium hydroxide storage unit;

[0115] a power source; and

[0116] Product dispensing device.

[0117] The generator of the second aspect may be conveniently located in a home or workplace to generate and dispense product as needed for cleaning and disinfecting applications.

[0118] The generator may include a saline reservoir. The saline reservoir may be an open tank or container at least partially filled with saline. In some embodiments, the size of the saline reservoir facilitates insertion and retention of the pool.

[0119] The generator may alternatively or additionally include a brine supply conduit. The brine supply conduit may be connected to the brine inlet of the pool and is adapted to supply brine from the brine reservoir to the pool. The brine supply conduit may include a tube, such as a flexible tube. The brine supply conduit may include a flexible plastic tube. In this way, the generator may be "plumbed-in" to ensure a direct supply of brine to the pool.

[0120] It would be particularly desirable to provide a hypochlorous acid generating device that is handheld, portable, convenient for use in different areas of the home or workplace, and powered by a rechargeable battery power source. However, in order to meet safety and compliance regulations, very good control of the output of the device is required. For battery powered devices, such control of the hypochlorous acid output is often challenging, for example due to the gradual decrease in voltage as the battery discharges. The inventors have addressed this problem by carefully controlling the power supplied to the device and controlling the flow rate through the first and second liquid outlets.

[0121] Thus, in some embodiments, the power source for the generator may be a battery, such as a rechargeable battery, such as a lithium-ion battery. This provides a device that is rechargeable and can draw power from the battery during use, providing a cordless, lightweight, handheld and portable device. This ensures that the device can be easily moved, for example to facilitate cleaning different rooms in a home or workplace.

[0122] The generator may include one or more motors. A motor may be provided to drive one or more pumps of the electrolytic cell. For example, when the electrolytic cell includes a first and a second peristaltic pump head, they may be driven by first and second corresponding motors, which in turn are powered by a power source.

[0123] As described above, providing a power cell power source for a hypochlorous acid generating device can be difficult because of the need for precise control of hypochlorous acid production. To address this issue, in some embodiments, the generator also includes a pulse width modulation (PWM) module connected to the cell to modify the voltage applied between the anode and cathode of the cell during electrolysis to provide an average voltage that does not drop as the cell discharges. This improves control and consistency of hypochlorous acid production.

[0124] In some embodiments, the generator further comprises a pulse width modulation (PWM) module connected to one or more pumps of the electrolytic cell. This improves control over the flow rate of the product out of the cell, further improving the consistency of the generated product.

[0125] Generally, in order to produce a stable and controllable output of hypochlorous acid, the hypochlorous acid generator must control (a) the sodium chloride concentration in the brine solution supplied to the cell, (b) the current supplied to the electrodes, and (c) the voltage between the electrodes. Therefore, in some embodiments, the generator includes a device for determining the sodium chloride concentration in the brine solution fed to the electrolytic cell. Suitable devices are known to those skilled in the art and include, for example, a detector for measuring the conductivity of the solution, which provides information about the sodium chloride concentration in the brine solution. In some embodiments, the generator includes a device for adjusting the sodium chloride concentration in the brine solution in response to the measured concentration. For example, if the measured concentration is above a predetermined threshold, the brine solution can be diluted with water to reduce the sodium chloride concentration before being fed to the cell.

[0126] In some embodiments, the voltage between the electrodes is controlled using PWM as described above to ensure a constant average voltage during electrolysis and improve the consistency of electrolysis. The constant average voltage can provide a constant effective current through the battery, thereby improving the consistency of product generation. Although the current can drop slightly over time due to reasons such as increased resistance caused by scale accumulation on the electrodes, this can be solved by using polarity switching to provide a cleaning cycle, and is expected to have a smaller impact than the current drop that occurs due to the voltage drop when the battery discharges in the absence of PWM.

[0127] In some embodiments, the generator further comprises means for combining the product streams in predetermined proportions. For example, sodium hydroxide solution and hypochlorous acid solution may be combined in predetermined proportions to provide a product having a predetermined pH or chemical composition, thereby providing a product that can be customized for a particular end use.

[0128] In some embodiments, the hypochlorous acid generator includes a control unit that facilitates controlling one or more of the first flow rate and the second flow rate of the liquid outflow pool. For example, the control unit can provide a user with a device that controls one or both of the first flow rate and the second flow rate. In some embodiments, the control unit provides a device that only controls the second flow rate. In some embodiments, the first flow rate is fixed and cannot be adjusted by the user.

[0129] By providing the user with a control unit that includes means for controlling the liquid flow rate in this way, the user is able to select specific settings or conditions of the generator so as to produce a liquid product having customized properties.

[0130] The flow rate can be controlled using any suitable device known to those skilled in the art. For example, the control unit may include an input device that allows a user to increase or decrease the flow rate. The input device may include, for example, a control knob or button. The control unit may include a display that includes an indication of the current flow setting. The control unit may include indicia, such as information on a digital display, that provides information about the properties of the product produced by the generator at the currently selected flow rate.

[0131] In some embodiments, the generator does not include any pumps at a location upstream of the cell. In some embodiments, the generator does not include any pumps at a location upstream of the first and second liquid outlets. In other words, the flow of liquid through the cell is achieved entirely by using one or more downstream pumps to "pull" the liquid through the cell and out of the liquid outlet, without the need for any pumps to "push" the liquid through the cell from upstream. It has been found that this arrangement can more accurately control the flow of liquid through the cell and is conducive to achieving a flow imbalance between the first and second liquid outlets. By "pulling" liquid from each outlet individually without any "pushing", the flow rate of the leaching outlet can be fine-tuned, and thus the composition of the electrolysis product leaving the generator can be fine-tuned.

[0132] A third aspect of the invention is a method for producing hypochlorous acid using a cell according to the first aspect, the method comprising:

[0133] allowing brine to enter the electrolysis chamber through a brine inlet;

[0134] applying a voltage across the electrical connections of the anode and cathode to electrolyze the salt water;

[0135] drawing a first product stream from a first liquid outlet at a first flow rate, the first product stream comprising hypochlorous acid; and

[0136] drawing a second product stream from a second liquid outlet at a second flow rate, the second product stream comprising sodium hydroxide;

[0137] The concentration of hypochlorous acid in the first product stream is higher than the concentration of hypochlorous acid in the second product stream.

[0138] In some embodiments, the second flow rate is higher than the first flow rate. In some embodiments, the second flow rate is at least 110% of the first flow rate, such as at least 115%, at least 120%, at least 125%, at least 130%, at least 135%, at least 140%, at least 145%, or at least 150% of the first flow rate. In some embodiments, the second flow rate is 110-250% of the first flow rate, such as 110-220%, 110-200%, 120-200%, 120-180%, 120-150%, 120-140%, or 130-140%.

[0139] In some embodiments, the second flow rate is at least 2 mL / min higher than the first flow rate, such as at least 5 mL / min or at least 10 mL / min. In some embodiments, the second flow rate is 11 mL / min higher than the first flow rate.

[0140] In some embodiments, the first flow rate is 2 to 30 mL / min, such as 3 to 25 mL / min, 4 to 24 mL / min, or 5.5 to 22 mL / min. In some embodiments, the first flow rate is about 5.5 mL / min.

[0141] In some embodiments, the second flow rate is 5 to 60 mL / min, such as 6 to 55 mL / min, such as 7 to 50 mL / min. In some embodiments, the first flow rate is about 7.7 mL / min.

[0142] In some embodiments, the method includes varying one or more of the first flow rate and the second flow rate to adjust the composition or property of the product produced at one or more of the first liquid outlet and the second liquid outlet.

[0143] In some embodiments, the method includes fixing the first flow rate and adjusting the second flow rate to change the composition of the first product stream drawn from the first liquid outlet. We have found that adjusting the second flow rate is a convenient way to change the pH value in the pool, thereby affecting the properties of the product dispensed from the first liquid outlet, as explained in detail above.

[0144] In some embodiments, the method includes fixing the first flow rate at a value F1 and adjusting the second flow rate F2 to change the composition of the first product flow withdrawn from the first liquid outlet, wherein F2>F1 both before and after the adjustment.

[0145] Ensuring that F2 remains higher than F1 throughout the process facilitates efficient extraction of hydrogen bubbles formed at the cathode from the second liquid outlet of the cell.

[0146] In some embodiments, F2 / F1 takes a value in the range of 1.1 to 2.0 before adjustment, and takes a value in the range of 1.1 to 2.0 after adjustment, wherein the values ​​of F2 / F1 before and after adjustment are different from each other. In this way, the relative flow rates before and after adjustment are different, thereby changing the composition of the product sucked from the first liquid outlet. In some embodiments, the value of F1 is the same before and after adjustment (i.e., the first flow rate F1 remains unchanged).

[0147] In some embodiments, the method includes fixing the first flow rate F1 at a value of 2 to 30 mL / min, and adjusting the second flow rate F2 from a first value in the range of 5 to 60 mL / min to a second value in the range of 5 to 60 mL / min that is different from the first value, wherein the first value and the second value of the second flow rate F2 are both 1.1 to 2.0 times greater than F1, for example 1.1 to 1.5 times, or 1.2 to 1.4 times.

[0148] In some embodiments, the method includes pumping a first product flow from a first liquid outlet at a first flow rate using a first peristaltic pump, and pumping a second product flow from a second liquid outlet at a second flow rate using a second peristaltic pump. The first and second peristaltic pumps may be located downstream of the respective first and second liquid outlets, thereby being arranged to "pull" liquid from each outlet.

[0149] In some embodiments, the method does not include any step of operating a pump upstream of the reservoir.For the reasons set out above in relation to the first aspect, "pulling" liquid through the reservoir has advantages over "pushing" liquid.

[0150] In some embodiments, the brine has a NaCl concentration of 0.5 to 20 g / L, such as 0.5 to 15 g / L, 0.5 to 10 g / L, or 1 to 10 g / L, prior to passing through the liquid inlet.

[0151] In some embodiments, the method further comprises reversing the polarity of the anode and cathode after a predetermined electrolysis period. Reversing polarity in this manner may be particularly useful when using hard water as a basis for making a brine solution. Using hard water can cause scale deposits to form on the electrodes during electrolysis, and the accumulation of deposits can reduce the efficiency of electrolysis. Reversing the polarity will help remove these deposits, allowing the cell to continue to operate properly.

[0152] In some embodiments, the method includes performing the reversals at intervals of up to 10 minutes.

[0153] In some embodiments, the ratio of operating time in normal (product generation) mode to operating time in polarity switching (cleaning) mode is 5:1 to 20:1, such as 5:1 to 15:1, such as 10:1 to 15:1, such as about 12:1.

[0154] In some embodiments, for each 60 minute period in normal (product making) mode, the method comprises running the cell in polarity switching (cleaning) mode for 2 to 10 minutes, such as 3 to 8 minutes, such as about 5 minutes.

[0155] In some embodiments, the cell is operated under constant current conditions. In other words, the cell is operated by supplying a fixed average current to the cell. This ensures consistent electrolysis and consistent product formation. Additionally, changes in voltage during constant current operation can be detected and can provide information about the current condition of the cell, such as whether scale has accumulated, causing a decrease in cell performance, and whether polarity reversal is required to remove scale from the electrodes and restore cell performance.

[0156] In some embodiments, the flow rate of saline into the liquid inlet is 2 to 50 mL / min, such as 5 to 50 mL / min, 2 to 22 mL / min, or 5 to 22 mL / min.

[0157] In some embodiments, the first product stream and the second product stream are combined in a predetermined ratio to provide a third product stream. For example, sodium hydroxide solution and hypochlorous acid solution can be mixed in a predetermined ratio to provide a third product stream having a predetermined pH value or chemical composition, thereby providing a product that can be customized for a specific end use.

[0158] In some embodiments, the method further comprises diluting one or more of the first product stream and the second product stream with water to provide a diluted product stream, wherein the diluted product stream has a NaCl concentration of less than 1 g / L.

[0159] In some embodiments, the pool is at least partially submerged in a brine reservoir containing brine, and the method includes drawing brine from the brine reservoir into the pool through the brine inlet.

[0160] In other embodiments, the saline is delivered to the saline inlet of the pool via a saline supply conduit. The saline supply conduit may be connected to the saline inlet of the pool and is adapted to supply saline from a saline reservoir to the pool. The saline supply conduit may include a tube, such as a flexible tube. The saline supply conduit may include a flexible plastic tube.

[0161] In some embodiments, the cell is operated at a current in the range of 0.4 to 1.5A, such as 0.5 to 1.2A, 0.6 to 1.0A, 0.7 to 0.9A, or about 0.8A.

[0162] In some embodiments, the cell operates at a voltage in the range of 5 to 20V, such as 6 to 18V, 6 to 15V, 6 to 12V, or 7 to 9V.

[0163] In some embodiments, the cell operates at a current in the range of 0.4 to 1.5A and a voltage in the range of 5 to 20V.

[0164] In some embodiments, the cell is operated at a current of about 0.8A and a voltage of about 7-9V.

[0165] In some embodiments, the voltage is delivered by a battery (a rechargeable battery such as a lithium-ion battery) through a pulse width modulation (PWM) module.

[0166] In some embodiments, the pH value in the cell is maintained in the range of 4.5 to 9.5 during electrolysis.

[0167] In some embodiments, the method includes adjusting the pH within the pool by adjusting one or more of the first and second flow rates.

[0168] A fourth aspect of the invention is a household cleaning product dispenser comprising an electrolytic cell according to the first aspect. The dispenser comprises a suitable dispensing device. Any suitable dispensing device known to those skilled in the art may be used, for example a nozzle, such as a pump action nozzle comprising a mechanical actuator. The mechanical actuator may be a trigger for a user to actuate to dispense the cleaning product.

[0169] In some embodiments, the household cleaning product dispenser includes a control device to adjust the composition of the product to be dispensed. In some embodiments, the control device may include an adjustable input adapted to change one or more of the first flow rate and the second flow rate to adjust the properties of the product, such as adjusting the pH of the product. In this way, a user of the household cleaning product dispenser may control the properties of the dispensed product and be able to adjust the properties of the product according to the intended use. BRIEF DESCRIPTION OF THE DRAWINGS

[0170] Figure 1 is a perspective cross-sectional view of an electrolytic cell according to a first embodiment of the present invention.

[0171] Figure 2 are (a) a top view of an electrolytic cell according to a first embodiment of the present invention, and (b) a bottom view of an electrolytic cell according to a first embodiment of the present invention.

[0172] Figure 3 is a side view of an electrolytic cell according to a first embodiment of the present invention.

[0173] Figure 4 is a schematic diagram showing unit operations of a hypochlorous acid generator according to an embodiment of the present invention.

[0174] Figure 5 are graphs of pH and HOCl output measured over a range of outlet flow deviations. DETAILED DESCRIPTION

[0175] Figure 1An exemplary embodiment of an electrolytic cell 1 according to the invention is shown, the figure showing a perspective view of the cell partly in section.

[0176] The cell comprises an anode 101 and a cathode 102 contained within a housing or casing 103 which defines an electrolysis chamber 104. The electrolysis chamber comprises the anode 101 and the cathode 102 with a membrane 105 disposed therebetween.

[0177] The housing 103 is made of acrylic and the thickness of the wall of the housing is 3-12 mm. The width of the housing is 58 mm and the total height of the housing is 80 mm.

[0178] Each of the anode 101 and the cathode 102 is made of titanium with an IrO2 / RuO2 mixed metal oxide catalyst coating. Each of the anode 101 and the cathode 102 is a mesh including a plurality of holes 106, 107.

[0179] The diaphragm 105 is made of lint-free cloth and has a thickness of 0.3 mm.

[0180] The spacing between the anode 101 and the cathode 102 is 3 mm. In the cell, the anode and cathode are parallel to each other.

[0181] The presence of the anode 101 and the cathode 102 within the cell divides the internal cell volume to define an inlet chamber 108 located between the anode 101 and the cathode 102, and includes a diaphragm 105, and two collection chambers: an anode collection chamber 109 located between the anode 101 and the inner wall of the outer shell 103, and a cathode collection chamber 110 located between the cathode 102 and the inner wall of the outer shell 103.

[0182] A first liquid outlet 111 is provided on a wall of the housing 103 near the anode 101. The first liquid outlet 111 consists of a short conduit 112 having an opening 113 in the wall of the housing 103. The conduit leads out of the housing from the opening for the liquid to flow out of the pool. The conduit extends into a short rod that terminates in an open end 114 that is suitable for connection to a pipeline (e.g., a flexible tube) to supply the liquid to a storage tank or a distributor (not shown). The rod of the conduit 112 has a beveled ring at the end around the opening 114 for connection to such a pipeline.

[0183] A second liquid outlet 115 is provided in the wall of the housing 103 near the cathode 102. The second liquid outlet 115 is similar to the first liquid outlet and consists of a short conduit having an opening in the wall of the housing 103. The conduit leads out of the housing from the opening for allowing liquid to flow out of the reservoir. The conduit extends as a short rod terminating in an open end suitable for connection to a conduit (e.g., a flexible tube) to supply liquid to a storage tank or dispenser (not shown). The rod of the conduit has a beveled ring at the end around the opening to facilitate connection to such conduit (note that for clarity, the rod is not shown). Figure 1 Features of the second liquid outlet similar to those of the first liquid outlet already discussed above are not labeled).

[0184] A first peristaltic pump head (not shown) is associated with a tube of a short conduit 112 connected to a first liquid outlet 111. Operation of the first peristaltic pump head is provided by the action of a separate motor (not shown) powered by a battery power source via a PWM module (not shown) to pump liquid out of the reservoir through the tube.

[0185] Similarly, a second peristaltic pump head (not shown) is associated with tubing connected to the second liquid outlet 115. Operation of the second peristaltic pump head is provided by the action of a separate motor (not shown) powered by a battery power source via a PWM module (not shown) to pump liquid out of the reservoir through the tubing.

[0186] The first and second peristaltic pump heads are each powered by the same battery via the same motor and PWM module.

[0187] The cell also includes a first electrical connection 116 extending from the housing 103 and electrically connected to the anode 101. Similarly, a second electrical connector 117 extending from the housing 103 is electrically connected to the cathode 102. The connectors 116 and 117 can be connected to an external power source (not shown), such as a battery, to apply a voltage between the anode and cathode to electrolyze the solution in the electrolysis chamber 104.

[0188] The same battery that supplies power to the first and second peristaltic pump heads via the motors also supplies power for electrolysis by delivering a voltage across the cell.

[0189] It will be appreciated by those skilled in the art that while the above explanation identifies the first electrode 101 as the anode and the second electrode 102 as the cathode, the identity of the electrodes as anodes or cathodes in practice depends on the polarity of the voltage applied to the electrical connections 115 and 116. Of course, the voltage applied to the connections can be reversed, in which case the electrode 102 will become the anode and the electrode 101 will become the cathode. Such a reversal may be useful, for example, in placing the pool in a cleaning state, as the polarity reversal will help remove undesirable deposits that may have accumulated on the electrodes during the electrolysis process, particularly when using hard water as the water source supplied to the pool.

[0190] from Figure 1 It can be clearly seen that a portion 118 of the wall of the housing 103 near the first liquid outlet 111 is angled towards the first liquid outlet 111. This provides a funnel-like structure of the inner wall of the housing 103, which funnels or narrows towards the opening 113 in the first liquid outlet 111. This helps to remove any air bubbles from the pool through the first liquid outlet.

[0191] Similarly, a portion 119 of the wall of the housing 103 adjacent to the second liquid outlet 115 is angled towards the second liquid outlet 115. This provides a funnel-like structure of the inner wall of the housing 103, which funnels or narrows towards the opening in the second liquid outlet 115. This helps to remove any air bubbles from the pool through the second liquid outlet.

[0192] The pool housing 103 defines an opening 120 at the base of the housing that provides fluid communication between the environment outside the housing 103 and a salt water inlet (not shown) located within the inner wall of the housing 103 at the base of the pool. The opening 120 is located at Figure 2 Thus, when housing 103 is placed within a liquid reservoir (eg, a saline reservoir), opening 120 allows liquid (saline) to flow into the pool.

[0193] Figure 2 (a) shows a top view of the cell 1, wherein the first and second liquid outlets 111, 115 and the first and second electrical connections 116, 117 can be easily seen.

[0194] Figure 2 (b) shows a top view of the pool 1, where the opening 120 in the pool can be seen.

[0195] Figure 3 A side view of the pool 1 is shown.

[0196] The cell can be used for the electrolysis of a brine solution (sodium chloride solution). To use the cell in this manner, a brine reservoir (not shown) needs to be prepared by dissolving sodium chloride in water. The consumer can do this as desired, for example at home or at work. The brine reservoir can be an open-top tank or container that is at least partially filled with brine prior to use of the electrolytic cell and is sized to be inserted and held in an upright position in the housing 103 of the electrolytic cell 1.

[0197] When the housing 103 is placed in such a reservoir and submerged in such a manner that the saline within the reservoir enters and covers the opening 120 at the base of the housing 103, drawing liquid from the first and / or second liquid outlets 111, 115 will initiate liquid flow through the pool, drawing liquid into the pool through the opening 120 in the base of the housing 103.

[0198] As the brine enters opening 120, it will flow through the brine inlet (not shown) into the central inlet chamber 108 portion of the electrolysis chamber 104. A first portion of the brine will enter a first half of the inlet chamber 108 on the side of the diaphragm 105 proximate to the anode 101, and a second portion of the brine will enter a second half of the inlet chamber 108 on the side of the diaphragm 105 proximate to the cathode 102. The flow conditions established by the operation of the peristaltic pump (not shown) are such that the first portion of the brine continues to flow toward the mesh structure of the anode 101 and eventually through the mesh structure of the anode into the anode collection chamber 109. Similarly, the second portion of the brine will continue to flow toward the mesh structure of the cathode 102 and eventually through the mesh structure of the cathode into the cathode collection chamber 110. At an appropriate time after the peristaltic pump is activated and liquid begins to flow through the cell, an appropriate voltage will be applied across electrical connections 116, 117 from a battery power source (not shown) via a PWM module (not shown). When the salt water contacts the anode 101, the solvated chloride ions in the solution will be oxidized to form chlorine, which in turn reacts with water to form hypochlorous acid. When the salt water contacts the cathode 102, the water molecules in the solution will be reduced to form solvated hydroxide ions.

[0199] In this way, the anode collecting chamber 109 will contain a relatively high concentration of hypochlorous acid solution, and the cathode collecting chamber 110 will contain a relatively high concentration of sodium hydroxide solution.

[0200] Continued operation of the peristaltic pump (not shown) draws hypochlorous acid solution from the tank through the first liquid outlet 111 and into a suitable conduit (not shown), which delivers the hypochlorous acid solution to a suitable container or dispenser (not shown). Sodium hydroxide solution is drawn from the tank through the second liquid outlet 115 and into a suitable conduit (not shown), which delivers the sodium hydroxide solution to a suitable container or dispenser (not shown).

[0201] During operation, the second peristaltic pump head generally provides a greater liquid flow rate than the first peristaltic pump head, so that the liquid flows out of the second liquid outlet 115 faster than the first liquid outlet 111. This helps extract hydrogen bubbles from near the cathode and establish a pH value in the cell that is conducive to the production of hypochlorous acid at the anode.

[0202] After performing the above-described polarity reversal (e.g., performed to clean the electrodes), it will be appreciated that the identity of the electrodes will be reversed, and similarly, the identity of the first and second liquid outlets will also be reversed. Thus, after the polarity reversal, the flow rate will be adjusted to ensure that liquid still flows out of the second liquid outlet (which was the first liquid outlet before the reversal) faster.

[0203] The user of the cell is able to adjust the flow rate out of the first and second liquid outlets 111, 115. By providing the user with the ability to adjust the flow rate, the user can customize the properties of the product produced by the cell.

[0204] The tank 1 may form part of a hypochlorous acid generator. Figure 4 A schematic diagram of an embodiment of a hypochlorous acid generator comprising a cell 1 is shown.

[0205] The brine is stored in a brine reservoir 2, which can be a simple container, such as a beaker into which the brine is injected or poured. A user (e.g., a consumer using the generator at home) can prepare a brine solution by adding table salt to tap water and mixing to dissolve and form a uniform solution. The brine is then fed into the pool 1. The brine can be delivered by a tube, or the pool can be simply placed in a brine reservoir to allow the brine to enter the inlet of the feed pool. The first peristaltic pump head 3 pumps the hypochlorous acid-rich product solution out of the pool. The second peristaltic pump head 4 pumps the sodium hydroxide-rich product solution out of the pool. Both peristaltic pump heads are driven by a motor 5, which is powered by a battery pack 8 (e.g., a rechargeable lithium-ion battery pack) via a pulse width modulation (PWM) module 11. The battery pack 8 also provides a voltage to the pool 1 via a second PWM module 9 to establish a voltage between the electrodes of the pool and drive electrolysis.

[0206] The hypochlorous acid solution from the tank is pumped into the storage container 6 via the peristaltic pump head 3. A third peristaltic pump head 10, also driven by the motor 5, can be used to pump brine from the brine container 2 directly into the storage container 6 in order to dilute the stored hypochlorous acid solution as required by the application.

[0207] The sodium hydroxide solution from the tank is pumped into the storage container 7 by the peristaltic pump head 4.

[0208] The hypochlorous acid solution in storage container 6 and the sodium hydroxide solution in storage container 7 can be dispensed, for example using a suitable dispenser (eg, a pump sprayer), and used for disinfection or cleaning purposes as required.

[0209] Example

[0210] Towards Figure 1-3 A brine solution was added to the electrolytic cell shown, and electrolysis was performed according to the process conditions shown in Table 1.

[0211] The anode flow rate was fixed as shown in Table 1, while the cathode flow rate varied.

[0212] When testing cells using a brine solution made with very hard water (hardness approximately 300 ppm calcium), switch the polarity of the cell at least every 10 minutes during electrolysis operation to remove scaling debris from the electrodes.

[0213] In each test run, electrolysis was performed for more than 200 hours.

[0214] Table 1

[0215] Example 1 Example 2 Example 3 Example 4 Brine NaCl concentration / g / L 4 4 4 4 Anode flow rate / mL / min 5.5 5.5 5.5 5.5 Cathode flow rate / mL / min 5.5 6.5 7.5 8.5 Current / A 0.8 0.8 0.8 0.8

[0216] Figure 5 The electrolysis operation results of Examples 1 to 4 are shown. With a fixed anode flow rate of 5.5 mL / min, the changes in HOCl output and pH value at three different cathode flow rates.

[0217] Example 1

[0218] At the equilibrium flow rates of Example 1 (5.5 mL / min at the cathode and 5.5 mL / min at the anode), the HOCl output was relatively low. Without being bound by theory, we believe that the lower cathode flow means that the H2 bubbles formed near the cathode are not fully released there. This causes more NaOH to seep into the cell, slightly increasing the pH, thereby increasing the amount of active chlorine at the anode in the form of sodium hypochlorite rather than hypochlorous acid. Although the solution's near-neutral pH (pH 7.4) makes it more suitable for delicate surfaces that may be damaged by lower pH values, and it still has disinfecting properties, the disinfecting ability of the solution will be lower due to the relatively low content of active chlorine in the form of HOCl.

[0219] Example 2

[0220] When the cathode flow rate is increased to 6.5 mL / min, the amount of HOCl produced at the cathode increases. The pH value is similar to that of Example 1. The slightly higher cathode flow rate removes more H2 gas from the cell, thereby increasing the amount of HOCl produced at the anode relative to Example 1.

[0221] Example 3

[0222] When the flow imbalance favoring the cathode was moderate (7.5 mL / min at the cathode and 5.5 mL / min at the anode), the highest amount of HOCl produced at the cathode was observed, about 9300 ppm.mL / min. The pH was slightly lower than that observed in Example 1 (about pH 6), further favoring the formation of HOCl at the anode. Without being bound by theory, we believe that this flow imbalance is sufficient to prevent H2 bubbles from accumulating at the cathode, thereby keeping the pH at the anode low enough to favor the formation of HOCl. However, the flow imbalance was not sufficient to cause a large amount of HOCl leakage to the cathode, so the HOCl output at the anode remained high.

[0223] Example 4

[0224] When the flow imbalance in favor of the cathode is very high (8.5 ml / min at cathode and 5.5 ml / min at anode), the HOCl generated begins to seep into the cathode stream, reducing the amount of HOCl generated. High cathode flow rates mean that more H2 is removed with the cathode stream, reducing the pH of the anode solution to around pH 1. This solution can be used in applications where a more acidic hypochlorous acid solution is required and will still have disinfecting properties, but due to the relatively low level of active chlorine in the form of HOCl, the disinfecting ability of the solution will be lower. Due to the high dissolved chlorine concentration and low pH, this product can be suitable for disinfecting hard surfaces. Also due to the high chlorine concentration, this product can also be used after dilution downstream.

[0225] Table 2 lists typical operating conditions of the electrolytic cell of the present invention.

[0226] Table 2

[0227]

[0228]

Claims

1. An electrolytic cell for producing hypochlorous acid and sodium hydroxide as separate product streams from brine, the electrolytic cell comprising: an electrolysis chamber, including an anode and a cathode; an electrical connection to each of the anode and cathode; a brine inlet into the electrolysis chamber for supplying a brine solution into the electrolysis chamber; a first liquid outlet from the electrolysis chamber proximate the anode; a second liquid outlet from the electrolysis chamber proximate the cathode; as well as at least one pump arranged to draw liquid from the electrolysis chamber at a first flow rate through the first liquid outlet and at a second flow rate through the second liquid outlet; wherein: (a) the first and second flow rates are variable relative to each other; or (b) The first flow rate and the second flow rate are fixed relative to each other at a predetermined flow rate difference.

2. The electrolytic cell of claim 1 , wherein the at least one pump comprises: a first pump arranged to draw liquid from the electrolysis chamber through the first liquid outlet at the first flow rate; as well as A second pump is arranged to draw liquid from the electrolysis chamber through the second liquid outlet at the second flow rate.

3. The electrolytic cell of claim 1 or 2, wherein each of the anode and cathode is liquid permeable.

4. An electrolytic cell according to any one of the preceding claims, wherein one or both of the anode and cathode comprise a metal substrate and a noble metal oxide catalyst supported on the substrate.

5. An electrolytic cell according to any one of the preceding claims, wherein the anode and the first liquid outlet are arranged so that at least a portion of the liquid flowing from the brine inlet to the first liquid outlet must flow through the anode; and / or The cathode and the second liquid outlet are arranged such that at least a portion of the liquid flowing from the brine inlet to the second liquid outlet must flow through the cathode.

6. An electrolytic cell according to any one of the preceding claims, comprising a housing defining an electrolysis chamber and containing an anode and a cathode, the housing including an opening in fluid communication with a brine inlet and the electrolysis chamber, so that when the housing is at least partially immersed in a brine reservoir, brine from the reservoir enters the housing through the opening and is drawn through the cell by operation of the at least one pump to draw liquid from the electrolysis chamber.

7. An electrolytic cell according to any preceding claim, comprising a porous membrane arranged between the anode and the cathode.

8. The electrolytic cell of claim 7, wherein the porous diaphragm is a lint-free cloth.

9. The electrolytic cell according to any one of claims 1 to 6, wherein the electrolytic cell does not comprise any diaphragm structure between the anode and the cathode.

10. An electrolytic cell according to any preceding claim, wherein the cell is configured to provide a higher liquid flow rate from the second liquid outlet than from the first liquid outlet.

11. The electrolytic cell of any one of the preceding claims, wherein the anode divides the electrolysis chamber into an inlet chamber located on a first side of the anode and adjacent to the cathode and an anode collecting chamber located on a second side of the anode, wherein the first liquid outlet is located in the anode collecting chamber; In use, liquid flows from the brine inlet into the inlet chamber, then passes through the anode into the anode collecting chamber, and then flows out from the first liquid outlet.

12. The electrolytic cell of any one of the preceding claims, wherein the cathode divides the electrolysis chamber into an inlet chamber located on a first side of the cathode and adjacent to the anode and a cathode collecting chamber located on a second side of the cathode, wherein the second liquid outlet is located in the cathode collecting chamber; In use, liquid flows from the brine inlet into the inlet chamber, then passes through the cathode into the cathode collecting chamber, and then flows out from the second liquid outlet.

13. An electrolytic cell according to any preceding claim, wherein each of the anode and cathode is liquid permeable and the cell comprises means for passing liquid through or around the electrodes.

14. A hypochlorous acid generator comprising an electrolytic cell according to any one of the preceding claims, further comprising: one or more of a saline reservoir and a saline supply conduit; Hypochlorous acid storage unit; Sodium hydroxide storage unit; Power source; as well as Product dispensing device.

15. A method of producing hypochlorous acid using a cell according to any one of claims 1 to 13, the method comprising: allowing brine to enter the electrolysis chamber through the brine inlet; applying a voltage at the electrical connection between the anode and the cathode to electrolyze the brine; drawing a first product stream from the first liquid outlet at a first flow rate, the first product stream comprising hypochlorous acid; as well as drawing a second product stream from the second liquid outlet at a second flow rate, the second product stream comprising sodium hydroxide; The concentration of hypochlorous acid in the first product flow is higher than the concentration of hypochlorous acid in the second product flow. The method of claim 15 , wherein the second flow rate is higher than the first flow rate.

17. The method of claim 15 or 16, wherein the brine has a NaCl concentration of 0.5 to 20 g / L before passing through the liquid inlet.

18. The method of any one of claims 15 to 17, further comprising reversing the polarity of the anode and cathode after a predetermined electrolysis period.

19. A method according to any one of claims 15 to 18, wherein the cell is operated under constant current conditions.

20. The method of any one of claims 15 to 19, wherein the flow rate of the saline into the liquid inlet is 2 to 50 mL / min.

21. A method according to any one of claims 15 to 20, wherein the first product flow and the second product flow are combined together in a predetermined ratio to provide a third product flow.

22. The method of any one of claims 15 to 21, further comprising diluting one or more of the first product stream and the second product stream with water to provide a diluted product stream, wherein the diluted product stream has a NaCl concentration of less than 1 g / L.

23. A method according to any one of claims 15 to 22, wherein the pool is at least partially submerged in a brine reservoir containing brine, and the method comprises drawing brine from the brine reservoir into the pool through the brine inlet.

24. A method according to any one of claims 15 to 23, wherein the cell is operated at a current in the range of 0.4 to 0.8 A and a voltage in the range of 5 to 20 V.

25. A method according to any one of claims 14 to 23, wherein the pH value within the cell is maintained in the range of 4.5 to 9.5 during electrolysis.

26. A household cleaning product dispenser comprising an electrolytic cell according to any one of claims 1 to 13.

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