Patent Application
20220396505
The present invention relates generally to an improved system and method for producing electrochemically activated (ECA) solutions. More particularly, the present invention relates to a system and method for producing cleaning, degreasing, sanitizing and disinfecting solutions utilizing the electrochemically activated water (EAW) process. In an advantageous embodiment, the present invention is a generator for producing hypochlorous acid (HOCl) solution and sodium hydroxide (NaOH) solution, and an associated method for controlling the pH of the HOCl solution and/or the free available chlorine (FAC) in the HOCl solution.
Many facilities, including hospitals, nursing homes, prisons, schools and public terminals, are highly susceptible to multi-drug resistant organisms (MDROs), commonly referred to as infectious bacteria and viruses. For example, the Centers for Disease Control and Prevention (CDCP) estimates that infections acquired from healthcare and food service facilities kill more individuals each year than vehicle accidents, breast cancer or AIDS. As a result, the Environmental Protection Agency (EPA) and the Food and Drug Administration (FDA) prescribe effective cleaning and disinfecting procedures to be used in facilities that provide healthcare services and/or food services. In response, hospitals, nursing homes, prisons and schools have instituted detailed cleaning and disinfecting protocols along with intensive training programs for environmental services personnel to ensure that areas accessed by patients, staff and the public are clean and hygienic.
The aforementioned facilities, especially healthcare facilities, have historically utilized a variety of high, medium and low level disinfectants, including formaldehyde, hydrogen peroxide, peracetic acid and chlorine-releasing agents (CRAs), including sodium hypochlorite, iodophor and phenol solutions. More recently, solutions of hypochlorous acid (HOCl) have been introduced as an efficacious and environmentally friendly alternative to traditional disinfectants. HOCl is a weak acid formed when chlorine dissolves in water and partially dissociates. Consequently, HOCl acts as an oxidizer and a primary disinfecting agent in a chlorine solution. The beneficial characteristics attributed to HOCl include that it is a highly effective disinfectant for destroying infectious bacteria and viruses, most notably C. diff, E-Coli, MRSA (Staph), Salmonella, Tuberculosis, Human Immunodeficiency Virus (HIV), and Severe Acute Respiratory Syndrome (SARS). Despite being highly effective, HOCl is relatively harmless to humans at concentrations sufficient for effective sanitizing and disinfecting. Consequently, HOCl solutions are approved for use as sanitizers and disinfectants in hospitals, nursing homes, prisons, schools and public terminals.
Other cleaning and disinfectant agents commonly used in the aforementioned facilities are not as environmentally friendly or as effective as HOCl in destroying harmful and deadly bacteria and viruses. As a result, it is not uncommon for individuals to contract serious illnesses from the bacteria and viruses at those facilities that are treated with other disinfectants. The inability to effectively destroy infectious organisms increases healthcare costs and causes physical harm to individuals that could have been prevented with the use of the more effective HOCl sanitizing and disinfecting agent.
Although highly effective, HOCl has a limited lifespan of effectiveness as a disinfectant, referred to commercially as its “shelf life.” Over time HOCl decomposes to chloric acid, hydrochloric acid, and oxygen; none of which separately exhibits the same desirable disinfectant properties as a full strength HOCl solution. The shelf life for HOCl solution as a sanitizing and disinfecting agent is limited from the time it is produced based on its free available chlorine (FAC) concentration. As used herein, the term “free available chlorine (FAC)” is intended to mean the portion of total chlorine in the solution that is present as hypochlorous acid (HOCl) or hypochlorite ion (OCl—). Consequently, it is imperative to take steps to ensure that an effective HOCl disinfectant solution is being used by environmental services personnel in an established cleaning and disinfecting protocol at facilities such as hospitals, nursing homes, prisons, schools and public terminals. In particular, it is essential that environmental services personnel use an HOCl solution that is within the life cycle of effectiveness that is acceptable for its cleaning, sanitizing and/or disinfecting purpose.
Another critical component in the production of an effective HOCl solution is control of the hydrogen ion concentration, commonly referred to as pH, of the solution. In the production of HOCl solution utilizing the EAW process, the co-product NaOH essentially dictates the pH of the HOCl solution because NaOH has a naturally higher pH. Consequently, the more NaOH present in the EAW process the higher the pH of the HOCl, and conversely, the less NaOH present in the EAW process the lower the pH of the HOCl. Existing systems for producing HOCl and NaOH solutions, referred to herein as generators, utilize a flow restricting valve in the form of a needle valve to increase or decrease backpressure on the NaOH output as a means for controlling the pH of the HOCl solution. The backpressure causes a portion of the NaOH solution in the NaOH output line to re-circulate back through the generator instead of into the NaOH receptacle. As a result, the additional NaOH solution in the generator raises the pH of the HOCl solution. As such, the pH of the HOCl solution can be adjusted upwards or downwards using the needle valve to increase or decrease the backpressure on the NaOH output and thereby increase or decrease, respectively, the NaOH solution re-circulated through the generator.
The needle valve allows a technician to balance the flow of the NaOH solution between the generator and the NaOH output receptacle, and in so doing, calibrate the pH of the HOCl solution to a desired pH between about 5.5 and about 7.5, and more particularly between about 6.0 and about 7.0. However, the needle valve also has the negative effect of introducing the opportunity for inexperienced or inattentive technicians to tamper with the needle valve setting, thereby causing an inconsistent pH of the HOCl solution. Furthermore, the needle valve adversely increases the cost, complexity and maintenance of a generator for producing HOCl and NaOH solutions. Thus, it would be advantageous to eliminate the needle valve from the conventional generator, while maintaining a means for precisely controlling the pH of the HOCl solution and/or the FAC in the HOCl solution.
In view of the foregoing, it is apparent a need exists for an improved system and method for producing ECA solutions. A more particular need exists for a system and method for producing cleaning, degreasing, disinfecting and sanitizing solutions utilizing an EAW process. Furthermore, a specific need exists for a generator for producing HOCl and NaOH solutions, and a method for controlling the pH of the HOCl solution and/or the FAC in the HOCl solution. Such a system and method would necessarily produce environmentally safe and effective NaOH cleaning and degreasing solutions, as well as environmentally safe and highly effective HOCl sanitizing and disinfecting solutions in compliance with EPA and FDA requirements.
Certain aspects, objects, features and advantages of the invention will be made apparent, or will be readily understood and appreciated by those skilled in the relevant art, with reference to the exemplary embodiments of the invention described herein and shown in the accompanying drawing figures. It is intended that the certain aspects, objects, features and advantages of the invention set forth herein be construed in accordance with the ordinary and customary meaning of the elements, terms and limitations of the appended claims given their broadest reasonable interpretation consistent with this written disclosure and accompanying drawing figures. Some or all aspects, objects, features and advantages of the invention, as well as others not expressly or inherently disclosed herein, may be accomplished by one or more of the exemplary embodiments described herein and shown in the accompanying drawing figures. However, it should be appreciated that the written description and drawing figures are for illustrative purposes only, and that many modifications, substitutions or revisions may be made to the exemplary embodiments without departing from the general concepts of the invention and the intended broad scope and proper construction of the appended claims.
The aforementioned aspects, objects, features and advantages of the invention will be more fully understood and appreciated when considered with reference to the accompanying drawing figures, in which like reference characters designate the same or similar parts throughout the several views.
Exemplary embodiments of the present invention are described in greater detail and shown in the accompanying drawing figures. The embodiments described and shown herein are directed to an improved system and method for producing ECA solutions. More particularly, the present invention is an improved system and method for producing cleaning, degreasing, sanitizing and disinfecting solutions utilizing the EAW process. ECA is a technology that produces the non-synthetic and biodegradable biocide compound hypochlorous acid (HOCl) solution and the cleaning agent sodium hydroxide (NaOH) solution. An ECA solutions generator produces HOCl solution and NaOH solution from water, salt and electricity utilizing an electrolysis cell. In an advantageous embodiment, the present invention is a generator for producing HOCl and NaOH solutions, and an associated method for controlling the pH of the HOCl solution and/or the FAC in the HOCl solution. Various aspects, objects, features and advantages of the present invention are illustrated by exemplary embodiments of an improved system and an associated method for producing HOCl and NaOH solutions. In a particularly advantageous embodiment, the system and method includes a generator operable for controlling the pH of the HOCl solution and/or the FAC in the HOCl solution, as will be described in greater detail hereafter.
System 10 further comprises a first receptacle 16 that is likewise in fluid (flow) communication with the generator 30, and a second receptacle 18 that is also in fluid (flow) communication with the generator 30. First receptacle 16 is configured to receive and retain HOCl solution produced by the generator 30 through HOCl output conduit 16A. Similarly, second receptacle 18 is configured to receive and retain NaOH solution produced by the generator 30 through NaOH output conduit 18A. The first receptacle, also referred to herein as HOCl tank 16, is provided with a gravity nozzle in the form of a first spigot 16B for dispensing the HOCl solution from the HOCl tank 16 into another container, such as a spray bottle (not shown). Likewise, the second receptacle, also referred to herein as NaOH tank 18, is provided with a gravity nozzle in the form of a second spigot 18B for dispensing the NaOH solution from the NaOH tank 18 into another container, such as a spray bottle (not shown).
As shown in
Electrolysis cell 50 of generator 30 is configured to receive the mixture of fresh water and brine via the water/brine input conduit 48.
As best shown in
Cathode 52 is formed from a material that is at least a relatively good conductor of electricity. In an advantageous embodiment, cathode 52 (and consequently input end cap 62) is made of a stainless steel material, such as SS 316. Anode 54 likewise is formed of a material that is at least a relatively good conductor of electricity. In an advantageous embodiment, anode 54 is made of a titanium material, such as Ti 6Al-4V. Preferably, the titanium metal of anode 54 is provided with a coating 55 that inhibits the rapid corrosion caused by the highly corrosive environment within the electrolysis cell 50 of the generator 30 in the EAW process. As depicted by
The membrane 56 disposed between the radially inner cathode 52 and the radially outer anode 54 is formed from a material that has at least a relatively high porosity and has at least a relatively high hardness with sufficient tensile and compressive strength. In an advantageous embodiment, membrane 56 is preferably made of a ceramic material, such as aluminum oxide (Al2O3) or silicon dioxide (SiO2). The input chamber 58 and the output chamber 60 are each formed from a material that is at least relatively resistant to corrosion and that has at least a relatively high hardness. Preferably, input chamber 58 and output chamber 60 are each made of a hard plastic material, such as a thermoplastic polymer. By way of example and not limitation, in an advantageous embodiment the input chamber 58 and the output chamber 60 are each made of a high-density polyethylene (HDPE) material, also known as polyethylene high-density (PEHD) material. If desired, input conduit 48, HOCl output conduit 16A and NaOH output conduit 18A may be made of the same HDPE or PEHD material for purposes of material compatibility and cost reduction.
As best depicted by
Input chamber 58 is provided with a first input port 58A configured for introducing the mixture of fresh water and brine delivered to the electrolysis cell 50 through the water/brine input conduit 48. Input chamber 58 is also provided with a second input port 58B for a purpose to be described hereafter. As the mixture of fresh water and brine passes through the electrolysis cell 50, electricity is applied to an electrically conductive tab 54C provided on the anode 54 that serves as a positive terminal for the electrolysis cell 50. Another electrically conductive tab 62A provided on the input end cap 62 serves as a negative (neutral or ground) terminal for the electrolysis cell 50. Cathode 52 and anode 54 separate the electrically charged ions of the mixture of fresh water and brine across the porous membrane 56 into an NaOH solution at the cathode 52 and an HOCl solution at the anode 54 in a manner well known to those skilled in the art. As a result, the HOCl solution is available at an output port 60A provided on the output chamber 60 and the NaOH solution is available at an output port 60B likewise provided on the output chamber 60.
As previously mentioned, the pH of the HOCl solution is essentially dictated by the pH of the NaOH solution because NaOH has a naturally higher pH. Consequently, the introduction of additional NaOH into the EAW process results in a responsive increase in the pH of the HOCl solution. Conventional generators for producing HOCl solution and NaOH solution utilize a needle valve to create backpressure in the output line of the NaOH solution to introduce additional NaOH into the EAW process. However, a needle valve adds cost and complexity to the manufacture of the generator, while reducing the reliability and accuracy of the generator due to the opportunity for technician error and/or tampering. In addition, the inner walls of the needle valve also create flow turbulence that results in an inconsistent pH of the HOCl solution. The present invention eliminates the needle valve and other components of a conventional generator to thereby provide a more economical, less complex and more reliable system and method for producing ECA solutions. By way of example and not limitation, the improved system 10 and associated method of the present invention eliminates the need for internal pH monitoring, needle valve calibration and flow meter components of the generator 30.
As best shown in
It should be noted that in an advantageous embodiment, the FFR 70 is interchangeable so that the pH of the HOCl solution delivered to the HOCl tank 16 via HOCl output conduit 16A can be precisely controlled. As will be readily apparent to those skilled in the art, varying the diameter D2 of the fluid passageway 75 (the inner diameter of insert 74) and the length L of the insert 74 changes the backpressure created in the NaOH output conduit 18A and thereby the amount of the NaOH solution that is diverted through return conduit 60C and re-circulated through the electrolysis cell 50 in a calculable manner. Consequently, the dimensions D2 and L of the insert 74 can be selected to produce a desired hydrogen ion concentration to control the pH of the HOCl solution. Accordingly, the present invention provides an associated method of controlling the pH of an HOCl solution produced utilizing the EAW process by selecting the diameter D2 of the fluid passageway 75 and the length L of the insert 74 of the FFR 70 for the electrolysis cell 50 of the generator 30.
In an advantageous embodiment, the inner diameter D2 of the insert 74 is selected from the range of about 0.02 to about 0.08 inches, preferably from about 0.02 to about 0.07 inches, and most preferably from about 0.055 to about 0.0625 inches, wherein the outer diameter D1 of the insert 74 is about 0.25 inches. In general, the length L of the insert 74 is less for a smaller diameter D2 of the fluid passageway 75 and the length L of the insert 74 is greater for a larger diameter D2 of the fluid passageway 75. The appropriate dimensions D2 and L to produce an ECA solution having a desired pH may be determined by a site survey of the water hardness and pH at a particular installation site. In addition, it should be noted that the FFR 70 may be located at any point within the NaOH output conduit 18A between the NaOH return conduit 60C and the NaOH tank 18. By way of example and not limitation, the FFR 70 alternatively may be positioned within the NaOH output conduit 18A adjacent the fluid coupling leading into the NaOH tank 18, as depicted in
Furthermore, a FFR 80 configured in the same manner as FFR 70 described herein with reference to
As a result, the FFR 70 of the system 10 controls the pH of the HOCl solution and the FFR 80 of the system 10 controls the FAC in the HOCl solution produced by the generator 30 in the EAW process. Consequently, the FFR 70 and/or the FFR 80 reduce the complexity, cost and maintenance of the system 10, while increasing the flexibility and reliability of the system 10 since the purely mechanical FFR utilizes no moving parts and no electrical or computer controlled components.
The foregoing detailed description of exemplary embodiments of the system and associated method is merely illustrative of the general concepts and principles of the present invention. Regardless of the foregoing detailed description and illustrated embodiments, various other configurations of the system and other steps of the associated method, as well as reasonable equivalents thereof, will be readily apparent and understood by those having ordinary skill in the art. Accordingly, equivalents to those shown in the accompanying drawing figures and described in the written description are intended to be encompassed by the broadest reasonable interpretation and construction of the appended claims. Furthermore, as numerous modifications and changes to the exemplary embodiments will readily occur to those skilled in the art, the present invention is not to be limited to the specific configuration, construction, materials, manner of use and operation shown and described herein. Instead, all reasonably predictable and suitable equivalents and obvious modifications to the invention should be determined to fall within the scope of the appended claims given their broadest reasonable interpretation and construction in view of the accompanying written description and drawing figures in view of the combined teachings of the disclosures of the relevant prior art.
