Electrochemical Towel Apparatus and Operating Methods Thereof

FIELD AND BACKGROUND OF THE INVENTION

The present invention relates to towel dispensing apparatus such as disposable towel dispensing apparatus, and to methods of operating such apparatus to produce towels moistened with electrolyzed water.

There exist known methods for producing aqueous sanitizing solutions containing hypohalous acids (HOX) such as hypohalous chloride (HOC1). Figure 1 schematically illustrates a two-compartment electrochemical cell having an ion- exchange membrane 108 for producing such an aqueous sanitizing solution. Salt water (aqueous NaCl) feed 109 A, 109B is introduced to each compartment of the cell.

When electrically connected to a suitable power supply 101, the reactions that take place over the electrodes may be represented as follows: at the positive electrode (anode) 106:

2H ₂ 0^ 4H ⁺ + 0 ₂ +4e ^"

2NaCl^Cl ₂ + 2Na ⁺ +2e ^"

C1 ₂ +H ₂ 0^HC1 + HOC1

and at the negative electrode (cathode) 107:

2H ₂ 0+2e ^20H ^" +H ₂

At the positive electrode, water is electrolyzed to form hydrogen ions and oxygen. Chloride forms chlorine, which reacts with water to form HC1 and HOC1, which typically discharge 102 from the acidic compartment 104 of the cell at a pH within a range of 2-6, yielding electrolyzed water containing HOC1. Such electrolyzed water may serve as an aqueous sanitizing solution.

The membrane allows the transfer of cations such as Na ⁺ , which traverses the membrane and enters the negative compartment 105 of the cell. At the negative electrode, hydroxide (OH ^" ) is liberated, and hydrogen is evolved. The discharge 103 from the negative compartment may contain NaOH _(aq) , and typically has a pH of 8-13.

This process, which produces two product streams: acidic electrolyzed water and basic electrolyzed water, may be disadvantageous when solely one of the streams is to be utilized. SUMMARY OF THE INVENTION

According to an aspect of the present invention there is provided a method of producing a towel product moistened with an aqueous solution or electrolytic water containing a hypohalous acid (HOX), using a towel dispenser having a towel dispensing path, the method comprising: (a) producing, from a length of towel disposed in the towel dispenser, a length of treated towel, at least a portion of which is moistened with the aqueous solution containing the hypohalous acid (HOX); and (b) discharging the length of treated towel from the towel dispenser.

According to an aspect of the present invention there is provided a method of producing a towel product moistened with an aqueous solution or electrolytic water containing a hypohalous acid (HOX), using a towel dispenser having a towel dispensing path, the method comprising: (a) electrochemically generating, within the towel dispenser, an aqueous solution containing the hypohalous acid (HOX), such that a length of towel disposed in the towel dispenser becomes a length of treated towel, at least a portion of which is moistened with the aqueous solution containing the hypohalous acid (HOX); and (b) discharging the length of treated towel from the towel dispenser.

According to an aspect of the present invention there is provided a towel dispensing apparatus for producing an aqueous solution or electrolyzed water containing a hypohalous acid (HOX), and for moistening a length of towel of a roll of disposable towel therewith, the apparatus comprising: (a) a housing having an opening dimensioned to allow the length of towel therethrough; (b) a rotating axis, disposed within the housing, the rotating axis dimensioned to receive a core of the roll of disposable towel therearound; (c) a dispensing mechanism adapted, in an operative dispensing mode, with the roll of disposable towel disposed with the core around the rotating axis, and with an end of the roll of disposable towel engaged by the dispensing mechanism, to advance, or enable to advance, the length of towel along a towel dispensing path, and through the opening; (d) a production mechanism adapted to electrochemically produce, within the housing, the aqueous solution containing the hypohalous acid, and to provide the aqueous solution on the length of towel so as to produce a moistened length of towel that is moistened with the aqueous solution containing the hypohalous acid. According to an aspect of the present invention there is provided a towel dispensing apparatus for producing an aqueous solution or electroly ed water containing a hypohalous acid (HOX), and for moistening a length of towel of a roll of disposable towel therewith, the apparatus comprising: (a) a disposable towel dispenser; and (d) a production mechanism adapted to electrochemically produce, within the housing, the aqueous solution containing the hypohalous acid, and to provide the aqueous solution on the length of towel so as to obtain a length of towel that is moistened with the aqueous solution containing the hypohalous acid.

According to further features in the described preferred embodiments, the producing includes generating the hypohalous acid (HOX) within the towel dispenser.

According to still further features in the described preferred embodiments, the method further comprises detaching or tearing off the length of the treated towel to obtain the treated towel product moistened with the aqueous solution.

According to still further features in the described preferred embodiments, the discharging is effected by means of a discharge apparatus of the towel dispenser.

According to still further features in the described preferred embodiments, the discharging is effected via a discharge port or slot in the towel dispenser.

According to still further features in the described preferred embodiments, the hypohalous acid (HOX) within the aqueous solution includes hypochlorous acid (HOCl).

According to still further features in the described preferred embodiments, the hypochlorous acid (HOCl) makes up at least 50 mole%, at least 60 mole%, at least 80 mole%, at least 90 mole%, at least 95 mole%, or at least 99 mole% of the hypohalous acid (HOX), or wherein the hypohalous acid (HOX) is, or consists essentially of, the hypochlorous acid (HOCl).

According to still further features in the described preferred embodiments, the aqueous solution has a pH within a range of 2 to 12, 2 to 10, 2 to 8, 2 to 7, 2.5 to 6, 2.5 to 5.5, 2.5 to 5, or 2.5 to 4.5.

According to still further features in the described preferred embodiments, the aqueous solution further includes at least one alkali halide.

According to still further features in the described preferred embodiments, the aqueous solution further includes dissolved chlorine. According to still further features in the described preferred embodiments, the method further comprises, prior to the producing, providing the length of towel in the towel dispenser.

According to still further features in the described preferred embodiments, the length of towel in the towel dispenser is part of a roll of towel.

According to still further features in the described preferred embodiments, during at least a portion of the producing, the length of towel is in motion along the towel dispensing path within the towel dispenser.

According to still further features in the described preferred embodiments, the method further comprises providing, within the towel dispenser, a container containing the aqueous solution.

According to still further features in the described preferred embodiments, the container houses an electrochemical cell.

According to still further features in the described preferred embodiments, the method further comprises operating the electrochemical cell within the container to produce the hypohalous acid (HOX) or to substantially maintain a concentration thereof.

According to still further features in the described preferred embodiments, the producing includes applying the aqueous solution to the length of towel, to produce the length of treated towel.

According to still further features in the described preferred embodiments, the applying of the aqueous solution is effected by spraying.

According to still further features in the described preferred embodiments, the applying of the aqueous solution is controlled by a controller.

According to still further features in the described preferred embodiments, the method further comprises providing a demand indication for the towel product, by a user, the applying of the aqueous solution being triggered by the demand indication.

According to still further features in the described preferred embodiments, the demand indication is selected from the group of demand indications consisting of a demand input of the user of the paper towel dispenser, and a motion of a user within a pick-up path or line-of-sight of a motion sensor.

According to still further features in the described preferred embodiments, the producing includes electrochemical generation the hypohalous acid (HOX) within the towel dispenser.

According to still further features in the described preferred embodiments, the electrochemical generation is performed in an aqueous electrochemical cell.

According to still further features in the described preferred embodiments, the aqueous electrochemical cell is an asymmetric electrochemical cell having a positive electrode and a negative electrode, an electrochemical capacitance ratio (R _eC ) of the negative electrode to the positive electrode being at least 3 : 1, at least 5: 1, at least 6: 1, or at least 7: 1.

According to still further features in the described preferred embodiments, the method further comprising feeding the aqueous electrochemical cell with an aqueous, halide-containing solution.

According to still further features in the described preferred embodiments, the length of towel is a length of moistened towel moistened with an aqueous halide- containing solution, wherein the producing includes disposing the length of moistened towel along the towel dispensing path within the towel dispenser; and applying a voltage between electrodes disposed adjacent to the towel dispensing path, so as to electrochemically produce the hypohalous acid (HOX) of the aqueous solution on at least part of the length of moistened towel, so as to obtain the length of treated towel.

According to still further features in the described preferred embodiments, the aqueous, halide-containing solution contains at least 50ppm halide, at least 70ppm halide, at least lOOppm halide, at least 150ppm halide, at least 200ppm halide, at least 250ppm halide, or at least 300ppm halide, the halide optionally including, mainly including, consisting essentially of, or consisting of chloride.

According to still further features in the described preferred embodiments, the aqueous, halide-containing solution is tap water, the tap water containing at least 50ppm halide, at least 70ppm halide, at least lOOppm halide, at least 150ppm halide, at least 200ppm halide, at least 250ppm halide, or at least 300ppm halide.

According to still further features in the described preferred embodiments, the producing includes applying the aqueous, halide-containing solution to the length of towel to produce the length of moistened towel.

According to still further features in the described preferred embodiments, the applying of the aqueous, halide-containing solution is effected by spraying.

According to still further features in the described preferred embodiments, the applying of the aqueous, halide-containing solution is controlled by a controller.

According to still further features in the described preferred embodiments, the producing and the discharging are performed at least partially in a concurrent fashion.

According to still further features in the described preferred embodiments, the length of towel is made of paper.

According to still further features in the described preferred embodiments, the length of towel includes, or is made of, a woven fabric.

According to still further features in the described preferred embodiments, the length of towel includes, or is made of, a non-woven fabric.

According to still further features in the described preferred embodiments, the length of towel includes, or is made of, a natural fabric, or a synthetic fabric.

According to still further features in the described preferred embodiments, the towel roll is a paper towel roll, a roll of woven fabric, or a roll of non-woven fabric, the rolls being optionally perforated or optionally discontinuous (e.g., a series of spiraled wet wipes).

According to still further features in the described preferred embodiments, the towel dispensing apparatus further comprises a controller adapted to activate the production mechanism, in response to a user demand.

According to still further features in the described preferred embodiments, the production mechanism includes a sprayer assembly adapted to spray a liquid towards the towel dispensing path, within the housing.

According to still further features in the described preferred embodiments, the production mechanism includes a sprayer assembly adapted to spray a liquid towards the towel dispensing path, within the housing, such that in the operative dispensing mode, the liquid is sprayed by the sprayer assembly onto a surface of the length of towel disposed along the towel dispensing path, so as to moisten the length of towel.

According to still further features in the described preferred embodiments, the sprayer assembly includes a first electrochemical cell adapted, in the presence of an aqueous solution containing at least one alkali halide, to produce the aqueous solution.

According to still further features in the described preferred embodiments, the production mechanism includes at least a second electrochemical cell positioned such that, in the operative dispensing mode, the second electrochemical cell is disposed proximate to, or urged against, a portion of the length of towel along the towel dispensing path, and wherein, when the second electrochemical cell is in an electrochemically active mode, and the length of towel is moistened with an aqueous feed solution containing at least one alkali halide, the second electrochemical cell produces, from the aqueous feed solution, the aqueous solution containing the hypohalous acid, in situ, in pores within the length of towel, so as to produce the moistened length of towel moistened with the aqueous solution containing the hypohalous acid.

According to still further features in the described preferred embodiments, the dispensing mechanism is further adapted to advance the length of towel along the towel dispensing path, in response to a user demand.

According to still further features in the described preferred embodiments, the first electrochemical cell and/or the second electrochemical cell is an asymmetric electrochemical cell.

According to still further features in the described preferred embodiments, this asymmetric electrochemical cell includes: (a) at least a first electrode of a first polarity; and (b) at least a second electrode of a second, opposite polarity; wherein an electrochemical capacitance ratio (R _eC ) of the at least a first electrode to the at least a second electrode is at least 3 : 1, at least 5: 1, at least 7: 1, at least 10: 1, at least 12: 1, at least 15: 1, at least 20: 1, at least 30: 1, at least 50: 1, at least 100: 1, or at least 250: 1, and optionally, at most 1000, at most 800, at most 600, or at most 500.

According to still further features in the described preferred embodiments, an electrochemical method of producing a hypohalous acid (HOX), for use in conjunction with preferred embodiments of the inventive apparatus and methods, includes (a) in a first, semi-capacitive electrochemical stage, with the positive and negative electrodes immersed in the aqueous solution, applying a first electrical current between the positive and negative electrodes, such that: (i) a portion of the alkali metal cations (M ⁺ ) is adsorbed on a surface of the negative electrode in a capacitive mode, and (ii) the positive electrode produces the hypohalous acid from the halogen anions (X ^~ ), via a halogen intermediate, and liberates hydrogen ions (H ⁺ ); and subsequently, (b) applying a second electrical current between the positive and negative electrodes, in a second process stage, to produce the hypohalous acid in the aqueous solution, the aqueous solution containing the alkali metal cations (M ⁺ ); and the halogen anions (X ^~ ) corresponding to the hypohalous acid. The second current is generally much lower than the first current.

According to still further features in the described preferred embodiments, the applying of the second electrical current is initiated after a pH of the aqueous solution produced in the first stage is within a range of 2.0 to 4.0, or has stabilized within a range of 2.0 to 4.0.

According to still further features in the described preferred embodiments, the pH of the aqueous solution in the first stage is at least 2.2, at least 2.4, at least 2.5, or at least 2.6.

According to still further features in the described preferred embodiments, the pH of the aqueous solution in the first stage is at most 3.8, at most 3.6, at most 3.4, or at most 3.2.

According to still further features in the described preferred embodiments, the method further comprises replenishing the electrochemical cell of the spraying arrangement with a solution containing a dissolved alkali halide.

According to still further features in the described preferred embodiments, the method further comprises, subsequently to the replenishing, operating the asymmetric electrochemical cell by reversing a polarity between the positive and negative electrodes, such that the previously negative electrode, which is now a positively polarized electrode, desorbs the alkali metal cations and adsorbs the halide, and the previously positive electrode, which is now a negatively polarized electrodes, producing a basic solution containing a hypohalite (OX-) corresponding to the halide.

According to still further features in the described preferred embodiments, the method further comprises, subsequently to the producing of the basic solution: removing or completely removing the basic solution from the asymmetric electrochemical cell, so as to complete a regeneration of the negative electrode; replenishing the asymmetric electrochemical cell with a solution containing a dissolved alkali halide; and operating the asymmetric electrochemical cell to produce a hypohalous acid in an aqueous solution having a pH within a range of 2.0 to 4.5 or 2.0 to 4.0.

According to still further features in the described preferred embodiments, the method further comprises, subsequently to (b), rinsing the negative electrode with water, followed by drying the negative electrode, so as to regenerate the negative electrode. According to still further features in the described preferred embodiments, the initial concentration of the halogen anions or halides is at most 5M or at most 1M, and optionally, within a range of 0.001M to 5M, 0.001M to 2M, or 0.01M to 1M.

According to still further features in the described preferred embodiments, the at least one of the first current and the second current is applied such that a voltage across the positive and negative electrodes in the electrochemical sprayer is at most 5V, at most 4.5V, or at most 4V, and optionally, within a range of 2-4V.

According to still further features in the described preferred embodiments, the at least one of the first current and the second current is within a range of 1 to 2 amperes.

According to still further features in the described preferred embodiments, the second current of the electrochemical sprayer is at most 25%, at most 20%, at most 15%), or at most 12%> of the first current of the electrochemical sprayer.

According to still further features in the described preferred embodiments, the asymmetric electrochemical cell further comprises a switching mechanism, associated with the power supply, and adapted, in a third operative mode, to apply a third current between the first and second electrodes while reversing a polarity therebetween.

According to still further features in the described preferred embodiments, the processor is adapted to control the power supply such that with a solution containing alkali metal cations (M ⁺ ) and halogen anions (X ^~ ) corresponding to the hypohalous acid, disposed in the sprayer chamber, the third current is sufficient to desorb the alkali metal cations that were adsorbed on the surface of the first electrode, and to adsorb the halogen anions, so as to produce an alkaline solution containing a hypohalite (OX-).

According to still further features in the described preferred embodiments, the switching mechanism is responsive to the processor.

According to still further features in the described preferred embodiments, the first electrode includes, largely includes, or consists of, an activated carbon.

According to still further features in the described preferred embodiments, the second electrode includes, largely includes, at least one construct selected from the group consisting of a graphite sheet, a carbon cloth, a carbon paper, or a titanium sponge.

According to still further features in the described preferred embodiments, the cell is a membraneless asymmetric electrochemical cell. BRIEF DESCRIPTION OF THE DRAWINGS

The invention is herein described, by way of example only, with reference to the accompanying drawings. With specific reference now to the drawings in detail, it is stressed that the particulars shown are by way of example and for purposes of illustrative discussion of the preferred embodiments of the present invention only, and are presented in the cause of providing what is believed to be the most useful and readily understood description of the principles and conceptual aspects of the invention. In this regard, no attempt is made to show structural details of the invention in more detail than is necessary for a fundamental understanding of the invention, the description taken with the drawings making apparent to those skilled in the art how the several forms of the invention may be embodied in practice. Throughout the drawings, like-referenced characters are used to designate like elements.

In the drawings:

Figure 1 schematically illustrates a prior-art, two-compartment electrochemical cell having an ion-exchange membrane for producing an aqueous sanitizing solution, which may be used in conjunction with aspects of the present invention;

Figure 2 provides a schematic illustration of a towel dispensing apparatus having a sprayer, for producing disposable towels moistened with electrolyzed water, in accordance with aspects of the present invention;

Figure 2A provides a schematic, 3-dimensional view of a towel dispensing apparatus having a sprayer, for producing disposable towels moistened with electrolyzed water, in accordance with aspects of the present invention;

Figure 2B provides a partial 3-dimensional view of the towel dispensing apparatus of Figure 2;

Figure 2C provides a schematic illustration of the sprayer of Figure 2;

Figure 2D provides a schematic illustration of an electrode array or panel of the electrochemical arrangement of Figure 2;

Figure 3 is a schematic illustration of a single-compartment electrochemical cell for producing acidic electrolyzed water, which may be used in conjunction with aspects of the present invention;

Figure 4 is a schematic illustration of the single-compartment electrochemical cell of Figure 3, operated in regeneration mode, in conjunction with aspects of the present invention; Figure 5 is an exemplary, schematic electrical diagram of a towel dispensing apparatus for producing (disposable) towels moistened with electrolyzed water, in accordance with aspects of the present invention;

Figure 6 is a plot of hypochlorous anion (OO ) concentration as a function of the charge-discharge cycle number under constant current, applied to an asymmetric electrochemical cell;

Figure 7 is a plot of acidic pH development in the asymmetric electrochemical cell (low surface carbon side) of Figure 6, as a function of time (charge-discharge cycle number); and

Figure 8 is an equilibrium plot of available chlorine present as hypochlorous acid (HOC1), as a function of pH.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

The principles and operation of the asymmetric electrochemical cell technologies of the present invention may be better understood with reference to the drawings and the accompanying description.

Before explaining at least one embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and the arrangement of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments or of being practiced or carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein is for the purpose of description and should not be regarded as limiting.

Some aspects of the present invention relate to electrochemical apparatus and methods for the production of disposable hand towels and the like that are moistened with electrolyzed water. The inventive apparatus may be modifications of disposable hand towel dispensers that are well known in the art and have seen widespread commercial use. The moistened hand towels produced may possess antibacterial capabilities, and may be utilized for hygienic hand washing purposes. Moistened hand towels, particularly at higher pH levels, may be utilized for the treatment of skin problems, particularly acne, eczema, and oily skin. Such moistened hand towels may also be utilized to remove hazardous pesticide residues from the surface of fruits and vegetables. Some aspects of the present invention relate to electrochemical apparatus and methods for in-situ, well-controlled production of electrolyzed water (containing hypochlorous acid and/or alkali hypochlorite) on disposable hand towels that may pre- soaked with aqueous "feed" solutions, including tap water, that contain halogen ions (fluoride, chloride, bromide, and/or iodide). The aqueous feed solution may exhibit a pH within a wide range, e.g., from 2 to 10, and in some preferred embodiments, within a range of 2 to 6, 2 to 4.5 or 2 to 4.

The general method for the in-situ production of the electrolyzed water may be based on voltage polarity. Upon being in contact with the electrodes (e.g., graphite electrodes), a current is passed between the electrodes so as to produce the electrolyzed water. In some preferred embodiments, the concentration of hypochlorous acid within the aqueous solution moistening the hand towel (typically disposed within or between the fibers of the disposable hand towel) may be at least 10 ppm, at least 25 ppm, at least 40 ppm and more typically, within a range of 10-300 ppm, 30-300 ppm, 30-250 ppm, 50-250ppm, or 50-200ppm. In fact, an aqueous droplet entrapped within the disposable hand towel fibers, in conjunction with the graphite electrodes and a suitable electrical current or voltage, functions as an electrochemical cell, as described hereinbelow. The inventors have found that by providing suitable surface areas or electrochemical capacitance for the positive and negative electrodes (described hereinbelow), and appropriate positioning of the electrodes, as is known in the art, the current or voltage may be controlled so as to produce the electrolyzed water in-situ in the disposable hand towel, without damaging the delicate structure of the towel.

Since the hypochlorous acid, in terms of antibacterial activity, reaches its highest efficacy at low pH, it may be advantageous to pre-moisten the disposable hand towel roll with a low pH, aqueous saline solution (e.g., containing around 0.5% NaCl). Alternatively, alternate installation of graphite electrodes and high surface carbon electrodes may enable the production of hypochlorous acid in electrolytic water having a low pH, starting from disposable hand towel roll pre-wetted with neutral saline aqueous solution.

With reference now to the figures, Figure 2 provides a schematic, exemplary illustration of a towel dispensing apparatus or dispenser (which typically resembles a paper towel dispensing apparatus or dispenser 200) for producing absorbent sheets such as paper towels moistened with electrolyzed water, in accordance with aspects of the present invention. Aside from the sprayer assembly 210 and the electrochemical cell or cells described hereinbelow, paper towel dispensing apparatus 200 may be identical or substantially similar to any of various conventional paper towel dispensers. Paper towel dispensing apparatus 200 may have a housing 120, which may include, by way of example, a top housing section 122 and a bottom housing section 124. Housing 120 is equipped with an opening 126 for dispensing or discharging of a discharged length of a moistened, sanitizing towel or absorbent sheet such as moistened paper towel 128 therethrough. Opening 126 may be disposed in bottom housing section 124, or, as shown, in top housing section 122.

Top housing section 122 may be attached pivotally to bottom housing section

124, e.g., by means of hinges (not shown) or other known arrangements allowing top housing section 122 to be opened or removed for accessing the interior of dispenser 200. Typically, such access is needed for removing the empty (typically cardboard) roll core from axis 130, for mounting new paper towel rolls such as an inserted paper towel roll 132, and for other maintenance purposes. Axis 130 may be supported by at least one axis support 134, typically located at each side end of housing 120.

Top housing section 122 may typically be closed and held closed during operation of the electronic paper towel dispenser device by magnetic, friction or other suitable catches or latches (not shown), and may be locked closed by means of a key (not shown).

During operation, and upon demand, a length of paper towel 133 may be drawn from inserted paper towel roll 132, along a paper towel dispensing path (signi ied by arrow 140) within paper towel dispenser 200. In exemplary dispenser 200, this is effected by discharge rollers 150 and 152. Length of paper towel 133 may be supported or guided by top and/or bottom supports or guides 184 and 186.

Due to the close proximity of the discharge rollers 150 and 152 to the paper towel dispensing path 140, the rollers may be covered with electrodes, in a preferred embodiment, so as to electrochemically produce an aqueous solution containing hypochlorous acid (HOC1).

In some preferred embodiments, at least one of top and/or bottom supports or guides 184 and 186 may serve to support positive and negative electrodes or electrode arrays 182A, 182B such that they are fixed in close proximity to paper towel dispensing path 140, so as to electrochemically produce an aqueous solution containing hypochlorous acid (HOCl) when a length of paper towel 133, moistened with an aqueous, halide-containing feed solution, is drawn past electrodes 182A, 182B. In these embodiments, sprayer assembly 210 may be filled with such an aqueous, halide- containing feed solution.

In some preferred embodiments, inserted paper towel roll 132 may be a pre- moistened paper towel roll that has been pre-moistened with such an aqueous, halide- containing feed solution (e.g., a pre-moistened paper towel roll consumable that may be hermetically sealed in a package).

In some preferred embodiments, and especially when such a pre-moistened paper towel roll is utilized, a humidifying agent or apparatus may be disposed within the interior of dispenser 200.

In some preferred embodiments, electrodes 182A, 182B are positioned on opposite sides of paper towel dispensing path 140.

In some preferred embodiments, positive electrodes 182A and negative electrodes 182B are positioned on a single side of paper towel dispensing path 140.

At least one of discharge rollers 150 and 152 may be a drive roller. In an exemplary embodiment, discharge roller 152 is a drive roller, adapted to be driven by a strictly mechanical mechanism (e.g., by the user turning a connected rotating mechanism disposed outside of housing 120) or by a mechanical mechanism actuated by an electrical mechanism, both types of mechanism being well known in the art. The drive roller may be connected by a drive shaft (not shown) to a drive motor 153.

In some embodiments, the electrical mechanism may be actuated by an input element (e.g., button or switch) 156 disposed on housing 120.

In some embodiments, the electrical mechanism may be actuated by a sensor 158 such as a motion sensor, typically located on or near the front of housing 120.

In some embodiments, the electrical mechanism may be actuated by a sensor such as a motion sensor (not shown), typically located on or near discharge roller 152.

An electronics panel or electronics unit 160 is typically disposed within paper towel dispenser 200, and is described in greater detail hereinbelow, with respect to Figure 5.

With regard to moistening of the paper towel, the inventors have found that it may be advantageous for the paper towel to be moist, without being overly wet, which may compromise the structural integrity of the paper, and/or may result in dripping within the dispensing apparatus or while being detached or being used by the consumer. Thus, in some preferred embodiments, the water coverage on the paper towel may advantageously be at most 5ml or at most 4ml per 100cm ² of wetted paper towel, and more typically, at most 3.0ml, at most 2.5ml, at most 2.2ml at most 2.0ml, at most 1.8ml or at most 1.6ml, per 100cm ² of wetted paper towel.

In some preferred embodiments, the water coverage on the paper towel may advantageously be at least 0.3ml, at least 0.5ml, at least 0.8ml, at least 1.0ml, or at least 1.2ml, per 100cm ² of wetted paper towel.

While a typical application of some methods and apparatus of the present invention focuses on producing sanitizing (e.g., impregnated with electrolyzed water containing HOX) paper towels from a continuous roll of paper towel, it will be appreciated that the broad scope of the disclosed invention is not limited to paper towels, nor to the use of continuous rolls of towel. For example, in some preferred embodiments, a plurality of individual towels or wipes may be treated to produce disposable, sanitizing towels. Such a plurality of individual towels or wipes may be inserted into apparatus of the present invention as a roll of discontinuous sheets, for example, with adjacent sheets (made of paper, woven fabric, or non-woven fabric) spiraled so as to have a partial overlap. Preferably, in at least a portion of the overlapping area, such adjacent sheets adhere to one another (e.g., by means of an adhesive), or have an adhesive affinity towards one another (e.g., surface energy properties of the materials, and/or sheet topography). In some embodiments, the shear or peel force applied to a sheet disposed along towel dispensing path 140, would be sufficient to separate between adjacent sheets. Such force may be applied, by way of example, by a drive roller. U.S. Patent No. 7,294,378, which is hereby incorporated in its entirety by reference into the specification, for all purposes, discloses various rolls of wet wipes that may be used in a system and apparatus for dispensing wet wipes, and that could be used in conjunction with the present invention to produce disposable, sanitizing towels such as sanitizing wet wipes.

Figure 2 A provides a schematic, 3 -dimensional view of a paper towel dispensing apparatus having a sprayer 210, for producing paper towels moistened with electrolyzed water, in accordance with aspects of the present invention. Substantially as in Figure 2, housing 120 is equipped with opening 126 for dispensing or discharging of a length of paper towel 128 therethrough. In a preferred embodiment, opening 126 may be equipped with a cutting edge 129 such as a serrated blade or surface to facilitate detaching or tearing off (e.g., from paper towel roll 132) a length of the moistened, sanitizing paper towel 128 that has been dispensed via opening 126.

Figure 2B provides a partial 3-dimensional view of the paper towel dispensing apparatus of Figure 2. During operation, and upon demand, a length of paper towel 133 may be drawn from inserted paper towel roll 132, along a paper towel dispensing path (signified by arrow 140), between top and/or bottom supports or guides 184 and 186 between discharge rollers 150 and 152, and out of discharge opening 126 (shown in Figure 2A). One of discharge rollers 150 and 152 typically serves as a drive roller for driving/pulling length of paper towel 133 away from paper towel roll 132 and through discharge opening 126.

Figure 2C provides a magnified, schematic illustration of sprayer 210 of Figure 2, featuring sprayer electrodes 112A, 112B disposed within a fill chamber 113 of sprayer 210. The broad surfaces of electrodes 112A, 112B face each other, but are set apart at a distance, so as to allow the flow of liquid therethrough. These broad surfaces are generally aligned in a parallel manner with respect to one another. Fill chamber 113 may be equipped with a chamber filling port 116, for facile filling and refilling of fill chamber 113. Fluidly communicating with fill chamber 113 is spray nozzle 114, which may advantageously be disposed and aligned such that the liquid discharged therethrough is directed towards a length of paper towel 133 disposed along paper towel path 140 (both shown in Figure 2B), so as to produce a moistened length of paper towel.

Figure 2D provides a schematic illustration of an exemplary electrode array or panel such as electrode array 182A of the electrochemical arrangement of Figure 2. Exemplary array 182A contains a plurality of individual electrodes 183, fixedly supported in place by support 184.

In some preferred embodiments, electrode array 182A may solely include negative electrodes.

In some preferred embodiments, electrode array 182A may solely include positive electrodes.

In some preferred embodiments, electrode array 182A may include both positive and negative electrodes, for example, disposed in an alternate pattern. Materials of construction for the positive and negative electrodes are discussed hereinbelow.

Figure 5 is an exemplary, schematic electrical diagram of a paper towel dispensing apparatus for producing paper towels moistened with electrolyzed water, in accordance with aspects of the present invention. In some embodiments, a power source 125, which is typically disposed externally to dispenser 200, may connect to electronics unit 160 via a power source port 127 (e.g., a USB connection).

Electronics unit 160 typically includes a power supply 131, which in some embodiments, is electrically connected to an on-board battery 135 via a battery housing.

Power supply 131 may be responsive to a processing unit, such as a central processing unit (CPU) 145, which is typically equipped with an internal memory, but alternatively or additionally, may communicate with an external memory 146. At least one switch or modulating module 147, which may contain a plurality of individual switches, may be responsive to CPU 145.

Various electrical elements and arrangements may be powered directly by power supply 131, or indirectly (e.g., via CPU 145), depending on voltage requirements and other factors.

In some embodiments, switch module 147 is electrically connected to sprayer electrodes 112A, 112B disposed within sprayer assembly or sprayer 210, for example, to turn on or off, or otherwise modulate, the current to sprayer electrodes 112A, 112B.

In some embodiments, switch module 147 is electrically connected to positive and negative electrodes 182A, 182B within "in situ" electrochemical cell arrangement 180, for example, to turn on or off the current to electrodes or electrode arrays 182A, 182B

In some embodiments, switch module 147 is electrically connected to a mechanical pressurizer 191 associated with sprayer 210, such that responsive to CPU 145, sprayer 210 discharges, via spray nozzle 114, a portion of water or aqueous liquid disposed therein. Spray nozzle 114 may be disposed and aligned such that the liquid discharged therethrough is directed towards a length of paper towel disposed along paper towel path 140, so as to produce a moistened length of paper towel.

In some embodiments, switch module 147 is electrically connected to a water feed valve 192 associated with sprayer 210, such that responsive to CPU 145, a water or aqueous halide feed source (typically tap water containing relatively minute quantities of dissolved sodium chloride) may be introduced to sprayer 210.

Mechanical pressurizer 191 may be any of various elements or arrangements known in the art, and may typically include a piston adapted and positioned whereby, in an active mode, the internal volume or chamber of sprayer 210 is reduced. The increase in pressure within the chamber drives a dose of liquid out of the chamber through at least one aperture or orifice such as spray nozzle 114. The dose may be a fixed dose. In some preferred embodiments, the dose volume may be controlled by controlling the pressure applied by mechanical pressurizer 191.

A display 144 may also be responsive to CPU 145. In some embodiments, display 144 may have a first indicator (e.g., a LED light) for indicating that the cell is operating, and a second indicator for indicating that the desired pH has been obtained, such that the solution produced is ready for consumption. In some embodiments, the first indicator may indicate that the cell is operational (i.e., has attained an operational mode, while at least a second indicator indicates that the cell is non-operational (i.e., has not yet attained that operational mode, e.g., the pH level is still out of range, or the cell is operating in regeneration mode).

Figure 3 is a schematic illustration of an electrochemical cell 300 for producing acidic electrolyzed water, which cell may be used in conjunction with aspects of the present invention. In some preferred embodiments, electrochemical cell 300 is an asymmetric, typically single-compartment electrochemical cell. Electrochemical cell 300 includes a cell vessel or housing 310 adapted to contain at least one positive electrode 305 and at least one negative electrode 306. Positive electrode 305 and negative electrode 306 are electrically connected to a power supply 301, and with the water or aqueous solution disposed within cell housing 310, forms an electrical circuit.

The feed or operating solution 307 to asymmetric electrochemical cell 300 contains an alkali halide solute, typically Na ⁺ and/or K ⁺ , and chloride (CI ^" ). Other halides (e.g., fluoride, bromide, and iodide), including various mixtures thereof, may be utilized.

In some preferred embodiments, the pH of feed solution 307 may be set so as to obtain a sanitizing solution having a pH within a particular or pre-set range.

Asymmetric electrochemical cell 300, while having a structure similar to the electrochemical cell of Figure 2, may advantageously be used to produce electrolyzed water (or "sanitizing solution ^" ). The sanitizing solution may have a pH within a range of 2 to 12, 2 to 10, 2 to 8, 2 to 7, 2.5 to 6, 2.5 to 5.5, 2.5 to 5, 2.5 to 4.5, or 2.0 to 4.0. Electrolyzed water within a pH range of 2.5 to 4.5, or 2.0 to 4.0, may be particularly efficacious, from an anti-microbial standpoint.

In some preferred embodiments, an electrochemical method of producing a hypohalous acid (HOX), for use in conjunction with preferred embodiments of the inventive apparatus and methods, includes (a) in a first, semi-capacitive electrochemical stage, with the positive and negative electrodes immersed in the aqueous solution, applying a first electrical current between the positive and negative electrodes, such that: (i) a portion of the alkali metal cations (M ⁺ ) is adsorbed on a surface of the negative electrode in a capacitive mode, and (ii) the positive electrode produces the hypohalous acid from the halogen anions (X ^~ ), via a halogen intermediate, and liberates hydrogen ions (H ⁺ ); and subsequently, (b) applying a second electrical current between the positive and negative electrodes, in a second, faradaic process stage, to produce the hypohalous acid in the aqueous solution, the aqueous solution containing the alkali metal cations (M ⁺ ); and the halogen anions (X ^~ ) corresponding to the hypohalous acid. The second current is generally much lower than the first current.

In some embodiments, the electrochemical cell is designed or operated to achieve a pH within a range of 2.0 to 4.5 or 2.0 to 4.0.

In order to sufficiently reduce the pH of the aqueous solution to 4.5, 4.0 or less during the first, semi-capacitive electrochemical stage, the electrochemical capacitance ratio (Rec) of the negative electrode to the positive electrode being may be at least 3 : 1, at least 4: 1, or at least 5: 1, and more typically, at least 7: 1, and more typically, at least 10: 1, at least 12: 1, at least 15: 1, at least 20: 1, at least 30: 1, at least 50: 1, at least 100: 1, or at least 250: 1. Typically, the Re _C is at most 1000: 1, at most 700: 1, at most 500: 1, or at most 400: 1.

It will be appreciated that the lower pH to be attained ("target pH"), and/or the higher the initial pH of the feed solution, the larger the Re _C or the differential between the electrochemical capacitance of the negative electrode and the electrochemical capacitance of the positive electrode (A _ec ).

Similarly, increasing the volume of the aqueous solution within the electrochemical cell may require a larger Re _C and/or a larger A _ec .

Alternatively and additionally, the pH of the feed solution may be adjusted to achieve the target pH, even for other electrochemical capacitance ratios. Thus, an electrochemical cell similar to that of Figure 3, but having a more balanced electrochemical capacitance ratio (R _eC ) of the negative electrode to the positive electrode, may be used in electrochemical sprayer 210 and in "in situ" electrochemical cell arrangement 180.

Similarly, the product streams of prior-art electrochemical cell 100 may also be utilized.

Figure 4 is a schematic illustration of an asymmetric, typically single- compartment electrochemical cell 400 being operated in a regeneration mode. In this regeneration mode, alkaline electrolyzed water 402 is produced. Electrochemical cell 400, the structure of which may be identical or substantially identical to electrochemical cell 300 shown in Figure 3, includes a cell vessel or housing 410 adapted to contain at least one positive electrode 405 and at least one negative electrode 406. Positive electrode 405 and negative electrode 406 are electrically connected to a power supply 401, and with the water or aqueous solution disposed within cell housing 410, forms an electrical circuit.

As described hereinabove, the feed or operating solution 407 to the asymmetric electrochemical cell contains an alkali halide solute, typically Na ⁺ or K ⁺ , and chloride

(CO.

Significantly, the asymmetry in asymmetric electrochemical cell 400 is the opposite of the asymmetry in asymmetric electrochemical cell 300 described hereinabove: the surface area, or electrochemical capacitance of positive electrode 405 is appreciably larger than that of the at least one negative electrode 406.

During the regeneration mode, asymmetric electrochemical cell 400 may be used to produce electrolyzed water having a basic pH, for example, a pH of at least 10, at least 11, at least 12, or at least 13 or higher. Electrolyzed water at such an elevated pH of is particularly efficacious in degreasing applications and in removing pesticides from goods and produce.

Typically, solely one electrode (i.e., the low-surface area electrode) needs to be resistive to electrolysis reactions. For the high surface area electrode, relatively inexpensive materials such as activated carbon may be utilized.

In some preferred embodiments, and for various applications requiring basic or highly basic moistened towels, electrochemical cell 400 may be operated to obtain electrolyzed water having a basic pH, for producing moistened towels having the required basic pH.

Operation of the electrochemical sprayer arrangement is now described in more detail, and in exemplary fashion. With reference again to Figure 5, power source 125 is connected to the device, e.g., via a USB cable. When connecting the cell in this fashion, a voltage of up to about 5V may be applied between the high surface-area electrodes and the low surface area electrodes. The high surface-area electrodes are negatively polarized and electrostatically filled with counter ions (e.g., Na ⁺ and/or K ⁺ ), in a capacitive manner. The low surface-area electrodes are positively polarized and create electrochemical interactions with the solution, which result in the production of hypochlorous acid and hydrochloric acid. The pH may be determined by, or strongly influenced by, the surface area of the high surface-area electrodes with respect to the low surface-area electrodes (or more precisely, the electrochemical capacitance of the high surface-area electrodes with respect to the electrochemical capacitance of the low surface-area electrodes), the solution volume, and the cumulative charge applied. Using a particular surface area of the high surface area electrodes and a particular (often predetermined) solution volume, and by charging to the maximum electrochemical capacitance of the high surface-area electrodes, the cell can be constrained to produce the hypohalous acid around a particular or predetermined pH. The inventors have determined that a pH of around 2.8 (2.6 to 3.0, 2.7 to 3.0, or 2.7 to 2.9) may be optimal for the active hypochlorous acid, particularly for skin disinfection applications.

When the electrochemical sprayer 210 is connected to the power source, a low pH environment (e.g., pH = 3) may be achieved, and the solution produced may contain relatively concentrated hypochlorous acid. CPU 145 may be adapted to control the display 144 (e.g., to activate the green light) after calculating the cumulative charge consumption.

The CPU may be advantageously adapted to count the (cumulative) charge delivered between the electrodes over the time period of the 1 ^st operative mode (AQ), for example, using the equation:

where F is the Faraday constant, and V is the volume of the solution. The CPU may be advantageously further adapted to trigger or initiate the 2nd operative mode based on such a charge calculation, particularly when using a predetermined solution volume, or a solution volume within a particular range. Once the device enters the 2 ^nd operative mode, the current may be appreciably lowered, typically by tenfold. The CPU (in this 2 ^nd operative mode) may apply a maximal voltage of around 2 Volts. Once the volume of the solution decreases, the voltage will tend to increase (due to the nominal surface area of the electrode decreases). Consequently, the CPU may control the magnitude of the current such that the voltage does not exceed an undesired or otherwise predetermined value.

As disclosed hereinabove, at such a low pH, the hypochlorous acid is not stable, such that the concentration of hypochlorous acid drops with time. The inventors have found that by applying a relatively low current (e.g., via the on-board battery), after the high surface-area electrodes are "filled" with counter-ions, the high surface-area electrodes cannot continue to function in a capacitive mode, and begin to function in a faradaic mode. Thus, while maintaining a very low current between the low and high surface area electrodes, a target pH may be substantially sustained. In the faradaic mode, both electrodes break, or react with, the solution: the low surface-area electrodes produce H ⁺ ions and the high surface-area electrodes produce OH ^" ions; these react with the H ⁺ ions to produce water. It must be emphasized, however, that the low surface- area electrodes also create hypochlorite ions that are converted to hypochlorous acid. Consequently, maintaining such a low current replenishes the hypochlorous acid and makes up for the hypochlorous acid depleted over time, such that the concentration of hypochlorous acid in the solution of the electrochemical device or sprayer may be substantially constant over time, even at low pH values at which the hypochlorous acid is unstable.

One method of regenerating the negative electrode is to dry the negative, high- surface electrode after rinsing out the concentrated solution with water, e.g., tap water (to avoid fouling reactions). When the high-surface electrode is dry, the adsorbed counter-ions are released, thereby reducing the electric charge on the surface of the electrode.

In some preferred embodiments, the electrochemical sprayer utilizes a graphite electrode as the lower surface area electrode, and an activated carbon sheet, or a graphite sheet coated with activated carbon, as the high surface area electrode.

In some preferred embodiments, both positive and negative electrodes 112A, 112B of electrochemical sprayer 210 or both positive and negative electrodes 182A, 182B of "in situ" electrochemical cell arrangement 180, may be graphite electrodes. The electrodes may have similar levels of electrochemical capacitance, such that operation of the cell may be substantially fully faradaic. In this case, the target pH can be achieved by accordingly adjusting the pH of the aqueous feed solution, for example, adding the requisite amount of HC1 (in addition to the alkali halide salt) when the target pH is in an acidic range.

Figure 6 plots hypochlorous anion (OQ ) concentration as a function of the charge-discharge cycle number under constant current, applied to an electrochemical sprayer containing a 1M solution of NaCl. Periodically, the low surface area carbon cloth was positively polarized, using a constant current, up to a potential difference above 4 Volts (with respect to a reference electrode, in tap water), for 6 minutes, followed by negative polarization for 2 minutes, to obtain a neutral environment around the electrode, until the next polarization cycle. It can be observed that the electrode exhibits a substantially steady-state behavior over 100 cycles.

Figure 7 is a plot of acidic pH development in the sprayer (low surface area carbon cloth) as a function of time (charge-discharge cycle number). The power source was controlled by the on-board CPU to apply a potential of 5 Volts.

Figure 8 is an equilibrium plot of available chlorine present as hypochlorous acid (HOC1), as a function of pH. It may be seen that the hypochlorous acid is most stable when the pH is within a range of 4 to 5. At pH 2, where the hypochlorous acid is the most active, only about 70% of the chlorine in the system exists as hypochlorous acid, with the remaining 30% existing as active chlorine. It is thus evident that HOC1 is not stable in acidic media. Consequently, the acidic/oxi dative electrolyzed water product is best used immediately, to avoid a significant decrease in the concentration of the hypochlorous (or more generally, hypohalous) acid.

Since the efficacy of hypohalous acids such as hypochlorous acid as an antibacterial agent may decrease appreciably with time (often on the order of 10 minutes), the application of current or voltage may be synchronized with demand for the disposable hand towel demand.

Alternatively or additionally, during periods of low demand, or no demand, the electrochemical cell of the sprayer assembly may be controlled to operate at a relatively low magnitude of current or voltage, so as to substantially maintain the hypohalous acid concentration, or so as to substantially maintain the hypohalous acid concentration at or above a particular concentration threshold. As used herein in the specification and in the claims section that follows, the term "electrochemical capacitance", with respect to an electrode, is generally defined by:

C=Q E,

where C is the electrochemical capacitance (in F/g), Q is the charge (in coulombs) and E is the potential difference (in Volts) of the electrode with respect to a reference electrode. When possible, the electrochemical capacitance is yet more accurately calculated using the equation:

Cd=dQ/dE,

where Cd is the differential electrochemical capacitance,

Quantitative measurement of "electrochemical capacitance" is performed by cyclic voltammetry, as is known to those of skill in the art, and specifically, as disclosed by B.E. Conway, Electrochemical Supercapacitors: Scientific Fundamentals and Technological Applications (Kluwer Academic/Plenum Publishers, New York, NY (1999)), which is hereby incorporated by reference for all purposes as if fully set forth herein.

In cyclic voltammetry, the potential of the electrode (with respect to a reference electrode) is linearly scanned (usually starting from the initial immersion potential, which may be denoted as potential of zero charge (PZC) back and forth. The output is the current (vertical axis) versus the potential. Since the scan rate (dE/dt) is constant and the current (I) equals dQ/dt (t = time), dividing the current values from the vertical axis by the scan rate value provides the differential capacitance (Cd) with respect to the potential (i.e., Cd(E)). A more detailed description of such a conventional technique is disclosed by Conway.

As used herein in the specification and in the claims section that follows, the term "portable" with respect to an electrochemical device or cell, refers to a device or cell that can be freely ported, or freely moved around, by a user, while functioning in an operative, electrochemical mode using an on-board or other cordless power supply.

As used herein in the specification and in the claims section that follows, the term "percent", or "%", refers to percent by weight, unless specifically indicated otherwise.

Similarly, the term "ratio", as used herein in the specification and in the claims section that follows, refers to a weight ratio, unless specifically indicated otherwise. As used herein in the specification and in the claims section that follows, the term "largely includes", with respect to a component within a formulation, refers to a weight content of at least 30%, at least 40%, at least 50%, or at least 60%.

As used herein in the specification and in the claims section that follows, the term "mostly includes", or "mainly includes", typically with respect to a component within a formulation, refers to a weight content (or when relevant, molar content) of at least 50%.

The modifier "about" used in connection with a quantity is inclusive of the stated value and has the meaning dictated by the context (for example, it includes at least the degree of error associated with the measurement of the particular quantity). When used with a specific value, it should also be considered as disclosing that value.

It will be appreciated that certain features of the invention, which are, for clarity, described in the context of separate embodiments, may also be provided in combination in a single embodiment. Conversely, various features of the invention, which are, for brevity, described in the context of a single embodiment, may also be provided separately or in any suitable sub-combination.

Although the invention has been described in conjunction with specific embodiments thereof, it is evident that many alternatives, modifications and variations will be apparent to those skilled in the art. Accordingly, it is intended to embrace all such alternatives, modifications and variations that fall within the spirit and broad scope of the appended claims. All publications, patents and patent applications mentioned in this specification, as well as U.S. Provisional Patent Application Serial No. 62/209,399, PCT Application No. PCT/IB2016/055079, U.S. Patent No. 9,481,575, and U.S. Patent No. 7,294,378, and U.S. Patent Publication No. 20050139465 are herein incorporated in their entirety by reference into the specification, for all purposes, to the same extent as if each individual publication, patent or patent application was specifically and individually indicated to be incorporated herein by reference. In addition, citation or identification of any reference in this application shall not be construed as an admission that such reference is available as prior art to the present invention.