US20090283417A1

US20090283417A1 - Electrolytic Cell with Gas Driven Pumping

Info

Publication number: US20090283417A1
Application number: US12/468,781
Authority: US
Inventors: Justin Sanchez; Jeffrey Phillip Krom; Kevin Schwarz; Craig Milroy; Rodney E. Herrington
Original assignee: Miox Corp
Current assignee: De Nora Miox Inc
Priority date: 2008-05-19
Filing date: 2009-05-19
Publication date: 2009-11-19
Also published as: WO2009143184A2; WO2009143184A3

Abstract

An electrolytic cell that draws electrolyte from an electrolyte storage container to the inlet of the cell. The inlet of the cell preferably comprises a back flow prevention device that restricts flow of electrolyte from flowing back through the inlet of the cell. Gasses generated by the electrolysis operation, typically primarily hydrogen that is liberated at the cathode surface, forces electrolytic products such as oxidants out of the discharge port of the electrolytic cell, preferably in a continuous flow process.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority to and the benefit of filing of U.S. Provisional Patent Application Ser. No. 61/054,415, entitled “Electrolytic Cell with Gas Driven Pumping,” filed on May 19, 2008, which is incorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention (Technical Field)
The present invention relates to an electrolytic cell that preferably operates in continuous flow mode and preferably utilizes gas generated within the cell as the motive force to transfer fluid out of the cell.
2. Description of Related Art
Note that the following discussion refers to a number of publications and references. Discussion of such publications herein is given for more complete background of the scientific principles and is not to be construed as an admission that such publications are prior art for patentability determination purposes.
Electrolytic technology utilizing dimensionally stable anodes (DSA) has been used for years for the production of chlorine and other mixed-oxidant solutions. Dimensionally stable anodes are described in U.S. Pat. No. 3,234,110 to Beer, entitled “Electrode and Method of Making Same,” whereby a noble metal coating is applied over a titanium substrate.
An example of an electrolytic cell with membranes is described in U.S. Patent RE 32,077 to deNora, et al., entitled “Electrode Cell with Membrane and Method for Making Same,” whereby a circular dimensionally stable anode is utilized with a membrane wrapped around the anode, and a cathode concentrically located around the anode/membrane assembly. An electrolytic cell with dimensionally stable anodes without membranes is described in U.S. Pat. No. 4,761,208 to Gram, et al., entitled “Electrolytic Method and Cell for Sterilizing Water.”
Commercial electrolytic cells have been used routinely for oxidant production utilize a flow-through configuration that may or may not be under pressure that is adequate to create flow through the electrolytic device. Examples of cells of this configuration are described in U.S. Pat. No. 6,309,523 to Prasnikar, et al., entitled “Electrode and Electrolytic Cell Containing Same,” and U.S. Pat. No. 5,385,711 to Baker, et al., entitled “Electrolytic Cell for Generating Sterilization Solutions Having Increased Ozone Content,” and many other membrane-type cells.
In other configurations, the oxidant is produced in an open-type cell or drawn into the cell with a syringe or pump-type device, such as described in U.S. Pat. No. 6,524,475 to Herrington, et al., entitled “Portable Water Disinfection System.”
U.S. patent application Ser. No. 09/907,092 to Herrington, et al., entitled “Portable Water Disinfection System,” the specification of which is incorporated herein by reference, describes disinfection devices that utilize, in one instance, a cell chamber whereby hydrogen gas is generated during electrolysis of an electrolyte, and provides the driving force to expel oxidant from the cell chamber through restrictive check valve type devices. In this configuration, unconverted electrolyte is also expelled from the body of the cell as hydrogen gas is generated. In an alternate configuration in the same application, hydrogen gas pressure is contained in a cell chamber during electrolysis, but the pressure within the cell chamber is limited by the action of a spring loaded piston that continues to increase the volume of the cell chamber as gas volume increases. Ultimately, a valve mechanism opens, and the spring-loaded piston fills the complete volume of the cell chamber forcing the oxidant out of the cell chamber.
U.S. Pat. No. 7,005,075 to Herrington, et al., entitled “Gas Drive Electrolytic Cell,” the specification of which is incorporated herein by reference, teaches a disinfection device that incorporates an electrolyte solution and a gas head space within a closed electrolytic cell chamber. During electrolysis of electrolyte to a disinfectant solution, hydrogen gas is generated within the closed electrolytic cell thereby generating pressure within the closed cell. Upon completion of electrolysis of the electrolyte solution to produce the disinfectant solution, a discharge port on the electrolytic cell housing is opened. Gas pressure within the cell housing provides the motive force to expel all or most of the disinfectant out of the cell housing to such a point where the disinfectant solution is utilized. By definition, this device operates in batch mode.
Other inventions that utilize gas pressure generated from electrolysis are also described in the literature. U.S. Pat. No. 4,138,210, to Avedissian, entitled “Controlling the Pressure of a Gas Generator,” describes a gas torch that utilizes an electrolytic mechanism for generating and controlling pressure of hydrogen gas that is used as the feed gas for the torch. U.S. Pat. No. 5,221,451 to Seneff, et al., entitled “Automatic Chlorinating Apparatus,” describes a chlorine gas generating cell that operates at the same pressure as the treated water flow stream. Water under pressure flows through the closed cell and replenishes the electrolyte level in the cell. Partitions within the electrolytic cell maintain separation of the chlorine gas that is aspirated in the water stream. Chlorine and hydrogen gas generated within the cell maintain a pressure balance between the chlorine gas phase and the pressure of the liquid water flowing through the cell so that unconverted electrolyte is not drawn into the flowing water stream. U.S. Pat. No. 5,354,264 to Bae, et al., entitled “Gas Pressure Driven Infusion System by Hydrogel Electrolysis,” describes a system that generates and controls the production of oxygen and hydrogen gas in an electrolytic hydrogel process for the purpose of closely regulating the amount of liquid drugs that are delivered under gas pressure to the human body.
Inventions that use a gas bubble lift mechanism from boiling water, as in coffee makers, are also described in the literature. U.S. Pat. No. 4,331,067 to Mysicka et al., entitled “Coffeemaker”, and U.S. Pat. No. 4,744,291 to Wallin, entitled “Electric Coffee Maker” describe electric percolator type of coffee makers that utilize an electric heating coil with a check valve in the suction side of the coil. As water is boiled in the coil at the bottom of the coffee maker, the water vapor bubbles lift the liquid water up a tube to the top of the coffee maker. The check valve prevents back flow of the water in the coil. As the water is boiled out of the tube, water from a reservoir is gravity fed past the check valve to the heating coil thereby repeating or continuing the water heating cycle.

SUMMARY OF THE INVENTION

The present invention is a method for increasing an oxidant concentration in a solution, the method comprising the steps of transferring electrolyte from an electrolyte source to an electrolytic cell, electrolyzing the electrolyte to form one or more oxidants and gas the gas transferring the oxidants to a container, and increasing a concentration of oxidants in the container. The concentration of oxidants in the container is preferably between approximately three grams per liter of free available chlorine and approximately 15 grams per liter of free available chlorine. The container is preferably the electrolyte source. The outlet of the electrolytic cell is optionally disposed within the container, in which case the container is preferably configured so that the anode and cathode of the electrolytic cell do not contact the electrolyte or oxidant outside the electrolytic cell. The increasing step preferably comprises recirculating the oxidants in the container back through the electrolytic cell, thereby increasing an amount of oxidants in the container relative to an amount of electrolyte in the container. The method optionally further comprises the step of separating the oxidant from the electrolyte in the container, for example by flowing the oxidant along a winding path, thereby ejecting most of the electrolyte from the container before it is mixed with the oxidant. The method preferably further comprises the step of preventing the oxidants and gas from flowing through an inlet of the electrolytic cell back to the electrolyte source. The method preferably further comprises the step of controlling a volumetric flow rate and a concentration of oxidant transferred from the electrolytic cell, for example by flowing the electrolyte through the electrolytic cell vertically, horizontally, or at an angle therebetween. The method is preferably performed in a continuous flow mode.
The present invention is also a system for increasing oxidant strength, the system comprising an electrolyte source, an electrolytic cell for producing one or more oxidants and gas; the electrolytic cell comprising an inlet and an outlet; and a connection between the outlet and the electrolyte source for transferring the oxidants from the electrolytic cell to the electrolyte source. The system preferably further comprises a check valve preventing the oxidants and gas from flowing back through the inlet. The connection is formed by disposing the outlet within the electrolyte source, in which case the electrolyte source is preferably configured so that the anode and cathode of the electrolytic cell do not contact electrolyte or oxidant outside the electrolytic cell. The electrolyte source optionally comprises one or more weirs or a floating membrane for separating the oxidant and the electrolyte. The electrolytic cell is optionally disposed at an angle between horizontal and vertical. The system is preferably operated in a continuous flow mode. The concentration of oxidants in the electrolyte source is preferably between approximately three grams per liter of free available chlorine and approximately 15 grams per liter of free available chlorine.
Objects, advantages and novel features, and further scope of applicability of the present invention will be set forth in part in the detailed description to follow, taken in conjunction with the accompanying drawings, and in part will become apparent to those skilled in the art upon examination of the following, or may be learned by practice of the invention. The objects and advantages of the invention may be realized and attained by means of the instrumentalities and combinations particularly pointed out in the appended claims.

BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS

The accompanying drawings, which are incorporated into and form a part of the specification, illustrate several embodiments of the present invention and, together with the description, serve to explain the principles of the invention. The drawings are only for the purpose of illustrating a preferred embodiment of the invention and are not to be construed as limiting the invention. In the drawings:

FIG. 1 is a view of an electrolytic cell in a vertical orientation that cycles oxidant to a reservoir.

FIG. 2 is a system configuration with an electrolytic cell in a slanted orientation that cycles oxidant to a reservoir.

FIG. 3 is a diagram showing the relationship of oxidant concentration and flow rate with varying orientation angles of an electrolytic cell.

FIG. 4 is a plan view of a weir system in the electrolyte reservoir.

FIG. 5 is a system configuration of an electrolytic cell that transfers oxidant to a separate storage container.

FIG. 6 is a system configuration with the electrolytic cell immersed in the electrolyte reservoir.

DETAILED DESCRIPTION OF THE INVENTION

The present invention comprises an electrolytic cell and method for generation of electrolytic products preferably comprising oxidants that can be utilized to disinfect materials, surfaces, liquids, or airborne contaminants. An embodiment of the present invention is an apparatus to produce a disinfecting solution. The apparatus preferably comprises at least one electrolytic cell. The cell preferably comprises at least two electrodes wherein at least one electrode comprises at least one cathode and at least one electrode comprises at least one anode. The apparatus preferably comprises a control circuit for providing an electrical potential between at least one cathode and at least one anode, wherein the control circuit is in electrical contact with at least one cathode and at least one anode. The apparatus further preferably comprises a check valve on or in line with the inlet of the electrolytic cell to prevent backward flow of disinfectant solution.
During generation of oxidants, electrolyte is located within the cell housing between the anode and cathode, and a controlled electrical charge passes through the electrolytic solution from at least one cathode and at least one anode, thereby generating at least one oxidant in the electrolyte. It is well known to those versed in the industry that a single anode and a single cathode electrolytic cell configuration comprises a mono-polar electrolytic cell. In an alternative embodiment of the electrolytic cell, one primary anode and one primary cathode are opposed to each other, and intermediate electrodes are placed between the primary anode and primary cathode. With any number of intermediate electrodes, the electrolytic cell configuration is known as a bi-polar electrolytic cell configuration. An energy source in electrical contact with the primary anode and primary cathode and an optional control circuit deliver a controlled electrical charge preferably having a predetermined charge value.
An electrolytic cell housing preferably encloses the anode and a cathode, and electrolyte solution flows into the inlet of the cell. The source of electrolyte preferably comprises a storage container located at an elevation higher than the electrolytic cell. In this configuration, electrolyte from the storage container will gravity flow from the storage container to the electrolytic cell housing. Alternatively, electrolyte may be pumped into the cell either continuously or in batches.
In addition to liquid electrolyte, the electrolysis process typically also produces hydrogen gas at the cathode electrode. The fluid entering the electrolytic cell typically comprises a liquid such as a dissolved salt solution—typically sodium chloride brine. During electrolysis, hydrogen gas is formed. Subsequently, the discharge solution from the electrolytic cell typically comprises a two phase solution, the two phases being liquid and gas. With a back flow preventer, for example a check valve, on the inlet of the electrolytic cell, fluid cannot flow back through the inlet of the electrolytic cell. Flow can only go in one direction, to the outlet of the electrolytic cell. As gas is mixed with liquid in the discharge pipe exiting the cell, the mass density of the two phase discharge solution is lower than the mass density of the single phase fluid (liquid) entering the cell. If, for example, the source of the electrolyte solution is located at an elevation greater than the electrolytic cell, gravity will cause the liquid solution to flow in to the electrolytic cell since the force of gravity on the outlet port of the cell will be lower due to the lower mass density of the solution in the discharge column from the cell. Thus gas bubbles formed in the electrolysis process preferably create a gas lift effect in a tube or pipe connected to the outlet of the electrolytic cell. The effectiveness of this gas lift effect is a function of the gas generation rate, the specific gravity of the fluid in solution, the viscosity and surface tension of the fluid in the system, and the diameter of the discharge pipe or tube from the electrolytic cell.
In one embodiment of the present invention, oxidants produced within the electrolytic cell are preferably discharged from the outlet port of the electrolytic cell, through a tube or pipe, and then return back to the electrolyte storage tank. In this configuration, the electrolyte is continually re-circulated to the electrolytic cell whereby the electrolyte is converted to oxidants, and the oxidants are circulated back to the electrolyte storage tank, thereby gradually increasing the concentration of the oxidants in the storage tank. In this configuration, which preferably operates in a continuous flow mode, the duration of the re-circulating process determines the ultimate concentration of the oxidants in the storage tank. A high concentration oxidant can thus be created in the process. In an alternative embodiment of this configuration, the electrolytic cell can be immersed in the electrolyte solution with inlet and outlet ports on the cell housing immersed in the electrolyte solution.
In an alternative embodiment of the present invention, the discharge of oxidant from the electrolytic cell can be returned to a separate container and not returned back to the electrolyte storage tank. In this manner, a fixed concentration oxidant can be transferred to a separate oxidant storage tank for subsequent use as a disinfectant or sterilizing solution.
Referring to FIG. 1, electrolyte solution 26, preferably comprising a sodium chloride brine solution, is introduced into cell housing 10 which comprises positive anode 12 and negative cathode 13 wherein electrolyte solution 26 is electrolytically converted to an oxidant solution within the confined space of electrolytic cell 10. Any electrolyte solution for generating an oxidant may be used in accordance with the present invention. The rate of electrolysis in electrolytic cell 10 is preferably controlled by controller 28. Electrolyte 26 is stored in container 24 and transferred to electrolytic cell 10 where the electrolyte is converted to one or more oxidants 16 and then transferred out of electrolytic cell 10 back to container 24.
During electrolysis, hydrogen gas 14 is liberated at cathode 13 and accumulates in the upper spaces of cell housing 10. As hydrogen gas 14 accumulates in the upper portion of cell housing 10, gas pressure increases according to the well known gas equation, PV=nRT wherein P is the pressure of the gas, V is the volume of the chamber, n is the moles of gas, R is the molar gas constant, and T is the absolute temperature. The production of hydrogen gas 14 causes a motive force to transfer oxidant 16 back to container 24. Because of the difference in density of the fluid in supply line 20 versus the density of the two-phase fluid (liquid plus gas) in return line 18, gravity causes electrolyte 26 to flow through inlet pipe 20 to electrolytic cell 10. Back flow valve 22 prevents fluid and gas from flowing backwards up inlet pipe 20 in the fluid circuit. In the preferred embodiment of the present invention, electrolyte 26 is gradually converted to oxidant 16 in container 24. Because the system continually circulates fluid, a high concentration of oxidant 16 can be generated in container 24, preferably greater than 3 grams per liter free available chlorine but less than 15 grams per liter concentration of free available chlorine.
A variety of variables can impact the rate of oxidant production and concentration. For instance, the amperage or voltage applied to the anode and cathode electrodes will impact the production of oxidants. The size of the electrodes will impact the volume of oxidants produced. The flow rate will impact the concentration of oxidants assuming the energy applied to the anode and cathode electrodes remains constant. The angle of the electrolytic cell (i.e. the elevation difference between the inlet and outlet ports of the cell) will also impact the volume versus oxidant concentration. When the energy applied to the electrolytic cell remains constant, the total production of oxidants produced within the electrolytic cell over time will remain constant. However, as the electrolytic cell is disposed in a more horizontal position, the volumetric flow rate of solution will increase but the concentration of oxidants will decrease. When the orientation of the electrolytic cell is more vertical, the volumetric flow rate will be lower but the oxidant concentration will be higher. In both cases, however, the total mass of oxidants produced will be the same. The product of the volume of oxidants and the concentration of the oxidants will be the same in either case, no matter what the angle of orientation of the electrolytic cell may be.
In an alternative embodiment of the present invention shown in FIG. 2, electrolytic cell 30 is orientated at an angle to horizontal. Preferably, controller 48 provides power to anode 36 and cathode 37 within electrolytic cell 30. Electrolyte 46 is transferred from container 44 via inlet pipe 40 through backflow valve 42 to electrolytic cell 30 where oxidant 34 is produced within electrolytic cell 30 and then transferred via return pipe 38 back to container 44. Hydrogen gas 32 facilitates transfer of oxidant 34 to container 44 by means previously discussed. FIG. 3 shows the correlation between volumetric flow of oxidant 34 from electrolytic cell 30 and the angle of inclination of electrolytic cell 30 as the cell changes from the horizontal position (0 degree position) to the vertical position (90 degree position). At the horizontal position, gas dynamics cause more volume of fluid to be transferred with each bubble of gas. This results in higher flow rate of fluid through electrolytic cell 30. Since controller 48 applies a constant current to the electrodes in electrolytic cell 30, the total mass production of oxidants 34 remains constant. The mass production of oxidants 34 is the product of the concentration in milligrams per liter (mg/L) of oxidant 34 times the volumetric flow rate of oxidants 34. Since the volumetric flow rate of oxidant 34 is higher at the horizontal orientation of electrolytic cell 30, the concentration of oxidant 34 will be lower. Likewise, if the orientation of electrolytic cell 30 is in the more vertical direction, the volumetric flow rate of oxidant 34 through electrolytic cell 30 will be lower but the concentration of oxidant 34 will be higher. The concentration of oxidant 34 can have important consideration when it comes to field applications of oxidant 34. For instance, in drinking water applications, the concentration of oxidant 34 may need to be low to properly dose the water or other fluid to be treated. Likewise, it may be advantageous for oxidant 34 to have a higher concentration for applications such as cleaning of hard surfaces such as those in restaurants. In other applications, such as in a medical setting, it may be advantages to have concentrations of oxidant 34 at even higher settings. It should also be noted that other operating parameters can affect the concentration of oxidants 34. These other factors include the concentration of halide salts in electrolyte 46, the size of anode 36 and cathode 37, the amount of current applied on the electrodes by controller 48, and the sizes of inlet pipe 40 and return pipe 38, for example.
Empirical data indicates that the rate of oxidant production during the recycling operation, whereby oxidant is transferred back to the electrolyte container, causes a slowdown in the rate of oxidant concentration buildup as time proceeds in the process. Stated alternately, as time progresses the change in concentration slows down as the solution concentration increases. This can be caused by a number of factors, including the depletion of halide salt ions in the electrolyte solution, heating of the electrolyte solution causing increased ion mobility in the electrolytic cell, and other effects. In an effort to reduce these effects, it may be beneficial to create a fluid barrier to avoid rapid mixing of oxidant with electrolyte (such as brine) as the electrolyte enters the electrolyte storage container, thus enabling the utilization of most or all of the electrolyte before the oxidant is mixed with the electrolyte. This will have the effect of maintaining high concentration of halide salts as they enter the electrolytic cell, as well as maintaining lower temperatures entering the electrolytic cell, at least during the first hydraulic pass of the system. Weirs in the bulk storage tank, which create a long return path for the oxidant prior to the oxidant returning back to the storage tank, may be employed. Alternatively, a floating membrane can be used to segregate the two solutions. Or, the oxidant can be returned to a separate container from the electrolyte solution. When the electrolyte solution is depleted, valves or hydraulic mechanisms can be utilized to transfer the contents of the oxidant container to the electrolyte container.
FIG. 4 demonstrates one method for maintaining such a hydraulic barrier. This figure represents a plan view of electrolyte storage container 100. Electrolyte storage container 100 comprises weirs 104 which preferably provide a tortuous and long path for the fluid to flow. As oxidant is returned to electrolyte storage container 100 via oxidant inlet port 102, the oxidant follows a long path around weirs 104 within electrolyte storage container 100 (although the weirs may also be disposed outside of electrolyte storage container 100). This long path creates a “barrier” between the oxidant and the electrolyte as the electrolyte is ejected through electrolyte discharge port 106. In this manner, the electrolyte will exit discharge port 106 before it is exposed to significant concentrations of oxidant.
In the alternative embodiment of the present invention shown in FIG. 5, oxidants 56 can be transferred to separate oxidant storage container 70 rather than returned to electrolyte storage container 64. In this embodiment, electrolyte 66 is contained in electrolyte storage container 64 and transferred via inlet pipe 60 through back flow control valve 62 to electrolytic cell 50 where electrolyte 66 is converted to oxidants 56 as well as hydrogen gas 54, and the oxidant is transferred to oxidant storage container 70 via outlet pipe 58. Mass production of oxidants 56 is preferably controlled by controller 68 by applying the appropriate power to anode 52 and cathode 53 within electrolytic cell 50. By controlling the angular orientation of electrolytic cell 50 as discussed previously, the concentration and flow rate of oxidants 56 can be selected or varied for oxidants 56 ultimately stored in oxidant storage container 70. Use of storage container 70 is optional; oxidants 56 may alternatively be directly used for a desired application without first being stored.
In the alternative embodiment of the present invention shown in FIG. 6, electrolytic cell 82 can be substantially disposed within electrolyte storage container 88. Electrolyte 86 is drawn via back flow control valve 90 into electrolytic cell 82 whereby oxidants 80 are produced by power applied from controller 92 to electrodes within electrolytic cell 82. Hydrogen gas 84 produced within electrolytic cell 82 provides the motive gasses need to transfer oxidants 80 back into electrolyte storage container 88, thereby gradually increasing the concentration of oxidants 80 within electrolyte storage container 86. Electrolytic cell 82 can be configured within electrolyte storage container 86 in such a manner as to avoid electrical shorting of anode 94 and cathode 96 with electrolyte 86. For example, anode 94 and cathode 96 can extend out of a dry recessed compartment 98 in the bottom of electrolyte storage container 88.
Applications of the present invention are especially applicable to low-cost water treatment systems for the home-use and consumer market. However, it will be obvious to those versed in the art that this invention can be utilized in a variety of applications including spray bottle applications for surface cleaning, potable water treatment systems, wastewater treatment systems, swimming pool treatment systems, cooling tower treatment systems, and other applications where a disinfectant is utilized to treat a fluid.
Although the invention has been described in detail with particular reference to these preferred embodiments, other embodiments can achieve the same results. Variations and modifications of the present invention will be obvious to those skilled in the art and it is intended to cover in the appended claims all such modifications and equivalents. The entire disclosures of all references, applications, patents, and publications cited above are hereby incorporated by reference.

Claims

1. A method for increasing an oxidant concentration in a solution, the method comprising the steps of:

transferring electrolyte from an electrolyte source to an electrolytic cell;

electrolyzing the electrolyte to form one or more oxidants and gas;

the gas transferring the oxidants to a container; and

increasing a concentration of oxidants in the container.

2. The method of claim 1 wherein the concentration of oxidants in the container is between approximately three grams per liter of free available chlorine and approximately 15 grams per liter of free available chlorine.

3. The method of claim 1 wherein the container is the electrolyte source.

4. The method of claim 3 wherein an outlet of the electrolytic cell is disposed within the container.

5. The method of claim 4 wherein the container is configured so that an anode and cathode of the electrolytic cell do not contact the electrolyte or oxidant outside the electrolytic cell.

6. The method of claim 3 wherein the increasing step comprises recirculating the oxidants in the container back through the electrolytic cell, thereby increasing an amount of oxidants in the container relative to an amount of electrolyte in the container.

7. The method of claim 3 further comprising the step of separating the oxidant from the electrolyte in the container.

8. The method of claim 7 wherein the separating step comprises flowing the oxidant along a winding path, thereby ejecting most of the electrolyte from the container before it is mixed with the oxidant.

9. The method of claim 1 further comprising the step of preventing the oxidants and gas from flowing through an inlet of the electrolytic cell back to the electrolyte source.

10. The method of claim 1 further comprising the step of controlling a volumetric flow rate and a concentration of oxidant transferred from the electrolytic cell.

11. The method of claim 10 wherein the controlling step comprises flowing the electrolyte through the electrolytic cell vertically, horizontally, or at an angle therebetween.

12. The method of claim 1 performed in a continuous flow mode.

13. A system for increasing oxidant concentration, the system comprising:

an electrolyte source;

an electrolytic cell for producing one or more oxidants and gas; the electrolytic cell comprising an inlet and an outlet; and

a connection between the outlet and said electrolyte source for transferring the oxidants from said electrolytic cell to said electrolyte source.

14. The system of claim 13 further comprising a check valve preventing the oxidants and gas from flowing back through the inlet.

15. The system of claim 13 wherein said connection is formed by disposing the outlet within the electrolyte source.

16. The system of claim 15 wherein said electrolyte source is configured so that an anode and cathode of said electrolytic cell do not contact electrolyte or oxidant outside said electrolytic cell.

17. The system of claim 13 wherein said electrolyte source comprises one or more weirs or a floating membrane for separating the oxidant and the electrolyte.

18. The system of claim 13 wherein said electrolytic cell is disposed at an angle between horizontal and vertical.

19. The system of claim 13 operated in a continuous flow mode.

20. The system of claim 13 wherein a concentration of oxidants in the electrolyte source is between approximately three grams per liter of free available chlorine and approximately 15 grams per liter of free available chlorine.