System and method for preparation of antimicrobial solutions

Abstract

A system to prepare an antimicrobial solution by the electrolysis of brine is presented where the antimicrobial solution is a solution comprising HOCl that contains a HOCl concentration of 100 ppm or more at a pH of approximately 6.5. The system includes an electrolysis cell that is provided with a constant current by a digital DC power supply controlled by a microprocessor and a controlled brine concentration at a controlled rate, which can also be controlled by the microprocessor to deliver a fluid that is continuously observed by a pH probe and an ORP probe that provides input to the microprocessor to adjust voltage, pump rate and/or flow rate in a programmed manner by the microprocessor. A method to produce the antimicrobial solution, including a sporicidal solution, by the novel system is presented.

1 . An antimicrobial solution generating system comprising:
 a source of sediment free water;   a flow controller;   a source of brine;   a microprocessor having software to accept multiple input signals and generate multiple output signals wherein at least one of the input signals is provided by at least one user interfacing device;   a digital DC power supply;   at least one electrolysis cell;   a pH probe;   an oxidation/reduction potential (ORP) probe; and   a pump to deliver the brine solution into a stream of the sediment free water, wherein the microprocessor receives input signals from the pH probe and the ORP probe and provides at least one output signal to at least one of: the flow controller to set a flow; the power supply to set a voltage while having a constant current applied to electrodes of the electrolysis cell; and the pump to set a concentration of NaCl in a solution formed by combination of the water and the brine, wherein a solution comprising HOCl having a HOCl concentration of 100 to 1,000 ppm is generated.   
     
     
         2 . The system of  claim 1 , wherein the electrolysis cell comprises a pair of end-caps, an outer cylindrical electrode, an inner cylindrical electrode, and a cylindrical porous ceramic membrane situated between the inner and the outer electrodes. 
     
     
         3 . The system of  claim 2 , wherein one of the electrodes is an anode and comprises a titanium cylinder coated with a mixed metal oxide comprising ruthenium oxide. 
     
     
         4 . The system of  claim 1 , wherein the power supply has an AC input of 208 to 220 V and a DC output of up to 100 A and up to 100 V to the electrolysis cell. 
     
     
         5 . The system of  claim 1 , wherein the user interfacing device is a keyboard or a touch screen and wherein the interfacing device is local or remote to the microprocessor. 
     
     
         6 . The system of  claim 1 , further comprises at least one output device, wherein the microprocessor outputs a signal to be observed by an operator and/or recorded on a recording medium. 
     
     
         7 . The system of  claim 6 , wherein the output device comprises a display screen and/or a printer. 
     
     
         8 . The system of  claim 1 , further comprising a storage device wherein the input and output history and production and cleaning set points are stored. 
     
     
         9 . The system of  claim 8 , wherein the storage device is a magnetic, optical, or flash storage device. 
     
     
         10 . The system of  claim 1 , where in the solution comprising HOCl has a pH of 6.2 to 6.6. 
     
     
         11 . The system of  claim 1 , where in the solution comprising HOCl is produced at a rate of 50 to 5,000 L/hour. 
     
     
         12 . The system of  claim 1 , further comprising a flow indicator to deliver an input signal to the microprocessor. 
     
     
         13 . The system of  claim 1 , further comprising:
 a source of a cleaning solution;   a pump to deliver the cleaning solution;   at least one valve to selectively direct flow to one of a plurality of effluent outlets; and   at least one means to selectively deliver the brine or cleaning solution into the sediment free water, wherein the microprocessor directs the means to deliver to alternate between brine delivery for generation of the solution comprising HOCl and cleaning solution delivery for cleaning of the cell and the valve or valves to direct flow to one of the effluent outlets.   
     
     
         14 . The system of  claim 13 , wherein the means to selectively deliver comprises selectively powering only the pump to deliver brine or only the pump to deliver the cleaning solution. 
     
     
         15 . The system of  claim 14 , wherein the means to selectively deliver further comprises at least one 3-way valve or a plurality of valves. 
     
     
         16 . A method for producing an antimicrobial solution comprises providing water to at least one system according to  claim 1 , wherein a solution comprising HOCl having 100 to 1,000 ppm HOCl and a pH of 6.2 to 6.6 is produced at a rate of 50 to 5,000 L/hr per system. 
     
     
         17 . The method of  claim 16 , wherein the system according to  claim 13  alternates periods of solution comprising HOCl production and cleaning, wherein the production period is set at about 4 to about 6 hours and the cleaning period is set at about 2 to about 3 hours. 
     
     
         18 . The method of  claim 16 , wherein the system according to  claim 13  alternates periods of solution comprising HOCl production and cleaning, wherein the periods vary as determined by a program run on the microprocessor based on the input signals where the cleaning occurs only when the desired pH, ORP and minimum flow rate values cannot be maintained by changing the output brine pumping rate, flow rate and voltage. 
     
     
         19 . An antimicrobial fluid comprising an electrolytic solution comprising HOCl, wherein the HOCl concentration is 100 to 1,000 ppm and the solution's impurity profile is indicative of electrolysis of a NaCl solution, wherein solution conductance is less than 15 mS. 
     
     
         20 . The antimicrobial fluid of  claim 19 , wherein the HOCl concentration is 450 to 1,000 μm. 
     
     
         21 . The antimicrobial fluid of  claim 20 , wherein the HOCl concentration exceeds 450 ppm for more than 60 days after electrolytic production. 
     
     
         22 . The antimicrobial fluid of  claim 21 , wherein the HOCl concentration exceeds 90% of its original concentration for more than 180 days after electrolytic production.