Abstract:
An improved chlorination system for pools, spas, potable water supplies, and the like, provides a vertically oriented electrolytic cell connected between a pump and a lightly salinated pool. The cell preferably contains a metallic electrode, such as copper, and a precious metal coated titanium electrode, and has means for passing an electric current through the cell. The present invention further provides a novel electrode stack design, conducive for forming an efficient chlorinator comprising a plurality of interconnecting electrode stacks of separate electrical cells.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS  
       [0001]     The inventor hereof claims priority based upon and pursuant to U.S. provisional patent application Ser. No. 60/145,537 filed Jul. 26, 1999, U.S. provisional patent application Ser. No. 60/148,452 filed Aug. 12, 1999, U.S. non-provisional patent application Ser. No. 09/592,719 filed Jun. 13, 2000, now abandoned, and U.S. non-provisional patent application Ser. No. 10/173,359 filed Jun. 17, 2002, now U.S. Pat. No. ______ TBD. 
     
    
     BACKGROUND OF THE INVENTION  
       [0002]     1. Technical Field  
         [0003]     The present invention relates to systems for the electrolytic chlorination of bodies of water; and, more particularly, to such a system whereby a vertically oriented electrolytic cell containing a metallic electrode, such as copper, and a precious metal coated titanium electrode is connected between a pump and a body of water, such as a pool, spa, supply of potable water, or the like, containing a saline solution, and having means for passing an electric current through the cell. The present invention further provides a novel electrode stack design, conducive for forming an efficient chlorinator comprising a plurality of interconnecting electrode stacks of separate electrical cells.  
         [0004]     2. Description of Related Art  
         [0005]     As is well known, swimming pools, spas, and the like, must be chlorinated to prevent accumulation of algae and bacteria, transfer of disease, and the like. Heretofore, such chlorination has been accomplished by depositing relatively large quantities of sodium hypochlorite into the water to be gradually dissolved over time. Unfortunately, with this procedure, the high quantities of chlorine released immediately after the sodium hypochlorite has been added to the water gives off a strong and offensive odor that makes swimming unpleasant. Also, the high concentration of chlorine results in bleaching bathing suits, towels, and the like. Further, a high concentration of chlorine often results in eye and skin irritation, and may even discolor the swimmers&#39; hair. Obviously, none of these effects is desirable.  
         [0006]     On the other hand, between treatments, the chlorine level often falls below a biologically effective level, which allows buildup of bacteria and algae, and allows transfer of disease. This, too, is undesirable. Thus, the chlorine treatments systems of the prior art have not been entirely satisfactory.  
         [0007]     Various attempts have been made to provide systems for improving the effective treatment of such bodies of water. Such systems may comprise electrolytic cells for dissociation of a salt to yield a bioactive agent, or may provide for periodic infusion into a body of water of chlorine, provided, for example, by a floating reserve of chlorine tablets. Examples of such systems may be seen with reference to British Patent Number 1,426,017 to Miles; U.S. Pat. No. 3,792,979 to Clinton; U.S. Pat. No. 4,869,016 to Diprose et al.; U.S. Pat. No. 5,460,706 to Lisboa; and, U.S. Pat. No. 5,468,360 to David et al.  
         [0008]     None of these systems, however, are seen to provide the several benefits, features, and advantages of the present invention. Further, none are seen to provide an electrode stack design that is conducive for forming an efficient electrolytic cell comprising a plurality of independent, but electrically interconnected, electrode stacks forming adjacent cells within the common housing of a single chlorinator. Through use of such a chlorinator, better control of bioactive chlorination within a body of water may be maintained.  
       BRIEF SUMMARY OF THE INVENTION  
       [0009]     These disadvantages of the prior art are overcome with the present invention, and an improved method of chlorinating swimming pools, spas, potable water supplies, and the like, is provided which constantly maintains the water at a desired level of chlorination without significant variation and which prevents fading of clothing, discoloration of hair, irritation of skin and eyes, and other disagreeable and dangerous side effects, while discouraging growth of bacteria and algae, and ensuring that the water will be safe for bathers.  
         [0010]     These advantages of the present invention are preferably attained by providing an improved chlorination system for pools, spas, potable water supplies, and the like, comprising means for maintaining an approximate 0.7% saline solution in said body of water and providing a vertically-oriented electrolytic cell connected between the pump and the body of water. The electrolytic cell contains a metallic electrode, such as copper, and a precious metal coated titanium electrode, and has means for passing an electric current through the cell.  
         [0011]     The present invention further provides a novel electrode stack design, conducive for forming an efficient electrolytic cell comprising a plurality of interconnecting electrode stacks. Accordingly, provided is an electrode having a tab adjacent its top for electrical interconnection with other like-charged electrodes, and for offsetting oppositely charged, but similarly interconnected, electrodes in a staggered manner. Non-conductive spacer elements are provided between electrodes, and, further, between electrode stacks, to prevent current leakage and shorting therebetween. A plurality of electrically interconnected electrode stacks within a common housing form a plurality of independent, but electrically interconnected cells, within a single chlorinator. Electrical connection of this plurality of cells in series provides a highly efficient, low current, high yield chlorinator previously unknown in the art.  
         [0012]     Accordingly, it is an object of the present invention to provide an improved chlorination system for pools, spas, potable water supplies, and the like.  
         [0013]     Another object of the present invention is to provide an improved chlorination system for pools, spas, potable water supplies, and the like, which constantly maintains the water at a desired level of chlorination without significant variation.  
         [0014]     Still another object of the present invention is to provide an improved chlorination system for pools, spas, potable water supplies, and the like, which prevents fading of clothing.  
         [0015]     Yet another object of the present invention is to provide an improved chlorination system for pools, spas, potable water supplies, and the like, which prevents discoloration of hair.  
         [0016]     Yet still another object of the present invention is to provide an improved chlorination system for pools, spas, potable water supplies, and the like, which prevents irritation of skin and eyes and other disagreeable and dangerous side effects.  
         [0017]     A further object of the present invention is to provide an improved chlorination system for pools, spas, and the like, which prevents disagreeable side effects while discouraging growth of bacteria and algae, and ensuring that the water will be safe for its intended use.  
         [0018]     Still a further object of the present invention is to provide an improved chlorination system for pools, spas, and the like, comprising means for maintaining a 0.7% saline solution in said pool and providing an electrolytic cell connected between the pump and the pool, and containing a metallic electrode, such as copper, and a precious metal coated titanium electrode, and having means for passing an electric current through said cell.  
         [0019]     Yet still a further object of the present invention is to provide an improved chlorination system for pools, spas, and the like, comprising a novel electrode stack design, conducive for forming an efficient electrolytic cell comprising a plurality of interconnecting electrode stacks.  
         [0020]     Yet still another object of the present invention is to provide an improved chlorination system for pools, spas, and the like, wherein the chlorinator comprises an electrode having a tab adjacent its top for electrical interconnection with other like-charged electrodes, and for offsetting oppositely charged, but similarly interconnected, electrodes in a staggered manner.  
         [0021]     Yet still another and further object of the present invention is to provide an improved chlorination system for pools, spas, and the like, wherein the chlorinator further comprises non-conductive spacer elements provided between electrodes, and, further, between electrode stacks, to prevent current leakage and shorting therebetween.  
         [0022]     Still a further object of the present invention is to provide an improved chlorination system for pools, spas, and the like, wherein the chlorinator comprises a plurality of electrically interconnected electrode stacks within a common housing to form a plurality of independent, but electrically interconnected cells, within a single chlorinator, and wherein electrical connection of this plurality of cells in series provides a highly efficient, low current, high yield chlorinator.  
         [0023]     These and other objects, features, and advantages of the invention will become more apparent to those ordinarily skilled in the art after reading the following Detailed Description and claims in light of the accompanying drawing Figures.  
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0024]     Accordingly, the present invention will be understood best through consideration of, and reference to, the following Figures, viewed in conjunction with the Detailed Description of the Preferred Embodiment referring thereto, in which like reference numbers throughout the various Figures designate like structure and in which:  
         [0025]      FIG. 1  is a diagrammatic representation of a pool chlorination system embodying the present invention;  
         [0026]      FIG. 2  is a vertical section through an electrolytic cell of the chlorination system of  FIG. 1  showing a single electrode of each polarity;  
         [0027]      FIG. 2A  is a perspective elevation view of a single-cell electrode stack in accordance with the chlorination system of  FIG. 1 ;  
         [0028]      FIG. 2B  is a perspective elevation view of a three-cell electrode stack in accordance with the chlorination system of  FIG. 1 ;  
         [0029]      FIG. 2C  is a side elevation view of a three-cell electrode stack in accordance with the chlorination system of  FIG. 1 ;  
         [0030]      FIG. 2D  is a front elevation view of a three-cell electrode stack in accordance with the chlorination system of  FIG. 1 ;  
         [0031]      FIG. 2E  is a front elevation view of two exemplary electrode plates of an electrode stack in accordance with the chlorination system of  FIG. 1 ;  
         [0032]      FIG. 2F  is a perspective view of the electrode plate connecting elements for an electrode stack in accordance with the chlorination system of  FIG. 1 ;  
         [0033]      FIG. 2G  is a perspective view of a current header connecting rod showing its placement in association with the electrode plate connecting elements for an electrode stack in accordance with the chlorination system of  FIG. 1 ;  
         [0034]      FIG. 2H  is a perspective view of a current header connecting rod showing its preferred offset hole arrangement for placement in association with the electrode plate connecting elements for an electrode stack in accordance with the chlorination system of  FIG. 1 ; and,  
         [0035]      FIG. 3  is a perspective view of an assembled chlorinator in accordance with the chlorination system of  FIG. 1  showing the position of a three-cell electrode stack and an exemplary electrical connection between the stacks. 
     
    
       [0036]     It is to be noted that the drawings presented are intended solely for the purpose of illustration and that they are, therefore, neither desired nor intended to limit the invention to any or all of the exact details of construction shown, except insofar as they may be deemed essential to the claimed invention.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0037]     In describing preferred embodiments of the present invention illustrated in the Figures, specific terminology is employed for the sake of clarity. The invention, however, is not intended to be limited to the specific terminology so selected, and it is to be understood that each specific element includes all technical equivalents that operate in a similar manner to accomplish a similar purpose.  
         [0038]     In that form of the present invention chosen for purposes of illustration,  FIG. 1  shows a swimming pool  10  having strainer  11  and pump  12 , strainer  11  being provided advance of pump  12  to reduce introduction of floating debris into pump  12 . Pump  12  acts to deliver water through pipe  14 , filter  16 , delivery pipe  18 , filter inlet pipes  20 ,  22  and  24  to circulate water through pool  10 . In accordance with the present invention, chlorinator  26  is connected by inlet pipe  28  and return pipe  30  to cause water from pipe  14  to pass through chlorinator  26  for chlorination and be inserted into delivery pipe  18  to deliver the chlorine into pool  10 .  
         [0039]     As best seen in  FIG. 2 , chlorinator  26  is a hollow cylindrical member, preferably vertically-oriented, having cell stack containment housing  32  formed of electrically insulating material, such as clear polyvinyl chloride (hereinafter, “PVC”) tubing. Flanged union  34 , or other suitable removable cap, preferably of PVC, is provided atop housing  32 , through which are mounted a pair of current header connecting rod conductors  36 ,  38  which connect to electrodes  40 ,  42 , respectively.  
         [0040]     Direct current power supply  44  is connected by wires  46 ,  48  to current header connecting rod conductors  36 ,  38  in order to cause a low voltage (less than 12 volts) direct current to flow between electrodes  40 ,  42 . Metallic electrode  40  preferably is formed of copper and, in normal operation, is connected to the negative pole of power supply  44 , while electrode  42  preferably is formed of titanium and is coated with a precious metal, such as a platinum group metal or combination of platinum group metals, and, in normal operation, is connected to the positive pole of power supply  44 . It will be recognized by those ordinarily skilled in the art that the just-described normal operating polarity may be reversed in order to provide touch-free cleaning of electrodes  40 ,  42 .  
         [0041]     Turning again to  FIG. 1 , suitable means  50 , such as a porous float, feeder mechanism, dispenser, or the like, optionally are provided for adding water softener grade granular salt directly to pool  10  in order to enhance the electrical conductivity of the water. This is typically done by adding 40 pound bags of salt which dissolve into the water of the pool to maintain the salinity of the pool at approximately a 0.07% level, which is approximately equal to the salinity of human tears and, hence, will not cause irritation or discomfort to swimmers&#39; eyes. Any salt concentration which is lost in the pool as by backwashing the filter, pool leaks, or dilution can be replaced by adding appropriate amounts of salt directly to the pool water.  
         [0042]     While  FIG. 2  shows, for convenience of understanding, only a single electrode of each respective material and polarity, it will be recognized with reference to  FIGS. 2A-2E  and  FIG. 3 , along with the following discussion thereof, that a plurality of electrodes  40 ,  42  are provided for forming, in combination, one or more electrode stacks  52 . Within each electrode stack  52 , each electrode  40  is electrically connected in parallel with other electrodes  40 . Similarly, within each electrode stack  52 , each electrode  42  is electrically connected in parallel with other electrodes  42 .  
         [0043]     Accordingly, each electrode stack  52  forms an operable electrolytic cell within chlorinator  26 . Each electrode stack  52  is insulated from other electrode stacks by non-conducting spacer  54 , preferably formed of non-conducting plastic. As best seen in  FIG. 3 , each electrode stack  52  is electrically connected in series with other electrode stacks  52 .  
         [0044]     Accordingly,  FIGS. 2A-2H  and  FIG. 3  have been chosen to illustrate the preferred construction of chlorinator  26 , and, especially, the preferred construction of electrode stack  52 . Advantageous to the vertical construction and orientation of chlorinator  26 , in combination with the above-described flanged union  34 , electrode stack  52  is easily removable from clear containment housing  32 . Such construction aids operator viewing of the condition of the elements internal to chlorinator  26 , and is convenient to maintenance operations.  
         [0045]     Turning now to the details of preferred construction of chlorinator  26 ,  FIG. 2A  illustrates a single-cell electrode stack  52  of the present invention. A plurality of metallic plate electrodes  40 , preferably of copper, are alternately interspersed with a plurality of precious metal coated titanium plate electrodes  42 . Current connector tabs  56  preferably are formed integrally with electrodes  40 ,  42  adjacent the top thereof. Connecting hole  58   a  is provided within each tab  56 . Additional connecting holes  58   b  are provided within each electrode  40 ,  42  for purposes described more fully hereinbelow.  
         [0046]     A plurality of metallic spacers  60  are disposed between current connector tabs  56  of electrodes  40  at connecting holes  58   a  so as to electrically connect electrodes  40 , while bridging and separating electrodes  40  from oppositely charged electrodes  42 . Similarly, a plurality of titanium spacers  62  are disposed between current connector tabs  56  of electrodes  42  at connecting holes  58   a  so as to electrically connect electrodes  42 , while bridging and separating electrodes  42  from oppositely charged electrodes  40 . A plurality of non-conducting spacers  64  are disposed between each electrode  40 ,  42  at additional connecting holes  58   b  within each electrode  40 ,  42  in order to provide electrode stack  52  with sufficient structural rigidity for operation and handling of stack  52 , while maintaining electrical separation of each electrodes  40 ,  42 .  
         [0047]     Turning next to  FIG. 2B , a three-cell electrode stack  52  in accordance with the present invention is shown. Each cell is constructed substantially as described with reference to  FIG. 2A ; and, further, non-conducting spacer  54  separates each cell to prevent channeling of current between adjacent cells. As can be seen in this  FIG. 2B , and specifically advantageous to the present invention, current connector tabs  56  may be formed and disposed within each stack  52  so as to maintain appropriate electrical connectivity, while alternating in horizontal placement relative to each other stack  52 , similar to conventional paper file folder tabs. Such arrangement provides the ability to design an optimal number of electrodes  40 ,  42  forming an optimal number of separate stacks  52 , and resulting in a large number of adjacent, insulated, and separate, but electrically interconnected, electrolytic cells within a given size of containment housing  32 .  
         [0048]      FIG. 2C  illustrates further details of construction of a three-cell electrode stack  52  of the present invention. Titanium threaded rod  66  is carried within connecting holes  58   a  of tabs  56  of electrodes  42 . Titanium threaded rod  66  further carries titanium spacers  62 , and titanium nuts  68  are provided to assemble this portion of electrode stack  52 . Similar construction is made with regard to electrodes  40 ; however, it will be recognized that metallic threaded rod, spacer, and nut components are selected for compatibility of use and operation with electrodes  40 .  
         [0049]     It will be further apparent that, in order to provide electrode stack  52  with sufficient structural rigidity for operation and handling of stack  52 , while maintaining electrical separation of each electrode  40 ,  42 , a plurality of non-conducting spacers  64 , preferably of PVC material, are disposed between each electrode ˜ 40 ,  42  at additional connecting holes  58   b  within each electrode  40 ,  42 . Spacers  64  are carried by non-conducting threaded rods  70  and are joined together with non-conductive nuts  72 , both preferably of PVC material. Such an arrangement, in association with herein-described conductive elements, provides for desirable continuity of contact between electrode plates of like charge, while providing for desirable separation of electrode plates of unlike charge.  
         [0050]      FIG. 2D  further illustrates a three-cell electrode stack  52 , better showing from front elevation view the alternating, or staggered, current connector tabs  56  of the present invention. Also shown within  FIGS. 2D-2E  is a preferred connecting hole pattern for connecting holes  58   a  within current connector tabs  56 ; and, a preferred connecting hole pattern for connecting holes  58   b  within each of electrodes  40 ,  42 . As may be seen, alternating current connector tabs  56  of the present invention, are formed and disposed within each stack  52  so as to maintain appropriate electrical connectivity, while alternating in horizontal placement relative to each other stack  52 , similar to conventional paper file folder tabs, in order to obtain a maximized number of electrolytic cells within a chlorinator  26  of any given size.  
         [0051]      FIG. 2F  illustrates additional details of construction of electrode  40 ,  42  connecting elements for electrode stack  52  in accordance with the present invention. Shown are titanium threaded rod  66 , titanium spacers  62 , and titanium nut  68 , all for use in association with electrodes  42 . It will be recognized that similar construction is made with regard to electrodes  40 ; however, metallic threaded rod, spacer, and nut components are selected for compatibility of use and operation with electrodes  40 . It will be further recognized that similar construction is made with regard to non-conductive components for use in association with connecting holes  58   b ; however, non-conductive threaded rod, spacer, and nut components are selected for electrical insulation and structural rigidity characteristics of stack  52 , all consistent with the criteria hereinabove described.  
         [0052]     In  FIG. 2G , current header connecting rod  38  is shown in relative placement in association with connecting elements for electrode  42 . Current header connecting rod  38  is mechanically and electrically interconnected with titanium threaded rod  66  at a flattened portion near the bottom thereof, titanium spacers  62 , and titanium nuts  68  (not shown in this Figure). Current header connecting rod  38  may further be provided with threaded lughole  74  for attachment of a lug carrying wire  48 . Again, it will be recognized that similar construction is made with regard to electrodes  40 ; however, metallic threaded rod, spacer, and nut components are selected for compatibility of use and operation with electrodes  40 .  
         [0053]     Best seen with reference to  FIG. 2H , current header connecting rod  38  carries offset hole  76  within its flattened portion for use in association with threaded rod  66 . Offset hole  76  is positioned to one side of a central axis through current header connecting rod  38 . Through use of offset hole  76 , electrodes  40 ,  42  are better prevented from touching, and thereby, shorting, and allow for a more compact cell construction within the available space of chlorinator  26  and flanged union  34 . It will again be recognized that similar construction may be provided with regard to current header connecting rod  36 .  
         [0054]     Turning now to  FIG. 3 , an assembled three-cell chlorinator  26  in accordance with the present invention is illustrated. Best seen with reference to this Figure is the general position of an exemplary three-cell electrode stack  52  within containment housing  32 . Sealing containment housing  32  at its lower end is lower containment housing cap  78 , preferably formed of PVC material. Lower containment housing cap  78  provides for introduction of water via inlet pipe  28 . Flanged union  34  carries current header connecting rods  36 ,  38 .  
         [0055]     Electrical link  80   a  connects, in series, an exemplary first and second cell stack. Electrical link  80   b  connects, in series, the exemplary second cell stack and an exemplary third cell stack. Accordingly, electrical interconnection of the stacks, in series, is completed. Following exposure within chlorinator  26 , treated water is exhausted via return pipe  30 .  
         [0056]     It will be observed that chlorinator  26  of the present invention, constructed as described herein, allows current header connecting rods  36 ,  38  to assume a central position at the top of stacks  52 ; thereby, ensuring even current flow distribution to stacks  52 . Such an arrangement minimizes heat build-up at maximum design current flow through connecting rods  36 ,  38  to electrodes  40 ,  42 . Accordingly, no ancillary cooling means are generally required for chlorinators of the present invention.  
         [0057]     Additionally, electrical series connection between stacks reduces the current required for equivalent chlorine production capacity, as compared to a single electrode stack design. Accordingly, smaller, lighter, and more cost-effective cables, transformers, and related ancillary electrical devices may be used in association with the present invention.  
         [0058]     Furthermore, the electrode tab configuration of the present invention provides for multiple cell stacks, in electrical series connection, to be accommodated within a single housing, minimizing space requirements and facilitating easy handling and removal of the overall cell stack for maintenance, scheduled cleaning, or the like.  
         [0059]     Such features render the present invention more economical, efficient, and safe than other prior art devices. Such features represent a distinct advance over other prior art devices.  
         [0060]     Accordingly, and with continuing reference to  FIG. 1 , pump  12  serves to circulate water from pool  10 , through filter  16  and chlorinator  26 , and returns the water to pool  10 . As the water flows through chlorinator  26 , electricity from power supply  44  produces an electrical current between electrodes  40 ,  42  which causes a chemical reaction in the water, changing the salty water to sodium hypochlorite and releasing free hydrogen, which is absorbed into the atmosphere.  
         [0061]     It is noted with regard to the production of free hydrogen gas that the vertical stack arrangement of chlorinator  26  is believed to be significantly safer than many other chlorinators currently available. This is because the vertical arrangement of chlorinator  26  provides, generally, a significantly smaller volume, as compared with horizontal units, within which the hydrogen gas may collect. Additionally, it will be recognized that chlorinator  26  of the present invention may be constructed without valves; thereby, avoiding unsafe compression of any trapped hydrogen gas.  
         [0062]     The sodium hypochlorite passes from chlorinator  26  through return pipe  30  and delivery pipe  18  to pool  10 , where it serves to prevent growth of algae and to disinfect the water of pool  10 . The rate at which the sodium hypochlorite is produced is relatively small, but is continuous. Consequently, the chlorine level in pool  10  remains at a desired level at all times and does not go through the fluctuations previously encountered when the sodium hypochlorite was added in crystalline form. Thus, the chlorine never reaches high levels where it could bleach bathing suits, turn hair green, or cause irritation of eyes and skin.  
         [0063]     On the other hand, the chlorine level never falls to such a low level as to allow bacterial growth or algae. Thus, the pool is protected safely and efficiently, without requiring periodic feeding of powdered chlorine and without the dangers and inconveniences that are encountered with the use of powdered chlorine.  
         [0064]     Having, thus, described exemplary embodiments of the present invention, it should be noted by those skilled in the art that the within disclosures are exemplary only and that various other alternatives, adaptations, and modifications may be made within the scope and spirit of the present invention. Accordingly, the present invention is not limited to the specific embodiments as illustrated herein, but is only limited by the following claims.