Abstract:
A method and apparatus turbulently exposes water flowing through a water system to a plurality of electrodes of an ion generator and provides a self-contained tank through which water flows. The generally cylindrical containment tank includes a tangential inlet pipe and an elliptical base having an outlet pipe. An aspect ratio, inlet pipe diameter versus containment tank diameter, is defined to achieve optimum ionization. A tank cover serves as the non-electrical conducting head for a plurality of electrodes which extend downwardly from the underside of the cover. The electrodes are functionally configured to maximize water flow between them. The rate of water flow within the containment tank is defined such that residence time of flow within the tank likewise optimizes water ionization. A sight glass allows for visualization of the container contents, and in particular anode wastage or wear, during operation.

Description:
FIELD OF THE INVENTION 
     This invention relates generally to methods and devices used with water systems. More particularly, it relates to a method and apparatus for exposing water which flows through a water system to an ion generator whereby ions which are generated are fed into the water flow to prevent fouling of the water system by algae, nuisance invertebrates, microorganisms, and inorganic salts. 
     BACKGROUND OF THE INVENTION 
     It has long been known that algae, nuisance invertebrates, microorganisms, and inorganic salts may foul water systems and lead to very significant water system inefficiencies. These inefficiencies result in increased energy consumption and increased maintenance demands which, in turn, increase overall operational and maintenance costs by several orders of magnitude. Ion generators have been employed in previous attempts to control algae, nuisance invertebrates, and microorganisms. Such ion generators are based on well-known principles of electrochemical reactions, one of which is referred to as electrolysis. Electrolysis is an electrochemical process by which electrical energy is used to promote chemical reactions that occur on the surface of functionally cooperating electrodes. One electrode, called the anode, involves the oxidation process where chemical species lose electrons. A second electrode, called the cathode, involves the reduction process where electrons are gained. In water, for example, oxygen is generated at the anode and hydrogen is generated at the cathode. The generation of hydrogen and oxygen in fresh water by the process of electrolysis will be weak due to the low electrical conductivity of the water. The oxygen generated aids in the prevention of the deposit of inorganic salts on the electrodes. The function of an ion generator is also to produce metal ions, typically copper ions or silver ions. Metal ion production is accomplished by use of an electrically charged metal anode which comprises atoms of the metal ions which are to be generated. It is the purpose of the ion generator to feed the metal ions out of the generator before they can be deposited on a cathode. Such depositing completely defeats the purpose of the ion generator as it is intended to be used in the application described here. The metal ions and oxygen, both of which are produced by the ion generator in the present application, are feed into the water stream of the water system to prevent fouling of the system by algae, nuisance invertebrates, microorganisms, and inorganic salts. 
     Copper, in its dissolved form, is one anthropogenic heavy metal that, although essential to biological functions in trace amounts, can be toxic at higher concentrations. The toxicity of copper to aquatic organisms is well established although the exact mechanism is not well defined. Copper toxicity is related to the form and, in general, copper must be in an ionic form in order for it to be toxic to invertebrates, microorganisms and algae. The eradication of microorganisms with copper ions is attributed to positively charged ions which are both surface active and microbiocidal. These ions attach themselves to the negatively charged bacterial cell wall of the microorganism and destroy cell wall permeability. This action, coupled with protein denaturation, induces cell lysis and eventual death. The in-water residence time for the biologically toxic portion of ionized copper may well be on the order of hours. One advantage to the use of copper ionization is that eradication efficacy is wholly unaffected by water temperature. Chlorine, a commonly used antifouling chemical, is somewhat temperature dependent. Furthermore, the copper ions actually kill the microorganisms, and other microorganism promoting bacteria and protozoa, rather than merely suppress them, as in the case of chlorine. This minimizes the possibility of later recolonization. Other advantages of copper ionization compared to other eradication techniques include relatively low cost, straight forward installation, easy maintenance, and the presence of residual disinfectant throughout the system. 
     A copper ion generator is, by way of specific example, an effective method for controlling legionella which is likely to be present in most water systems. Legionella is predominantly present in water cooling systems in microbial biofilms which become attached to surfaces submerged in the aquatic environment. These biofilms are typically found on the surfaces of pipes and stagnant areas of the water cooling system. Many components of most any man-made water system can be considered to be an amplifier for the organism (i.e., the organism can find a niche where it can grow to higher levels, or be amplified) or a disseminator of the organism. Examples of man-made amplifiers include cooling towers and evaporative condensers, humidifiers, potable water heaters and holding tanks, and conduits containing stagnant water. Showerheads, faucet aerators, and whirlpool baths may serve as amplifiers as well as disseminators. Human infection from exposure to legionella, or legionosis, can result in a pneumonia illness that is commonly referred to as Legionnaire&#39;s disease, namesake of the famous 1976 outbreak in Philadelphia. Since the Philadelphia outbreak, about 1,400 cases are officially reported to the Center for Disease Control annually. 
     Other bacteria and protozoa can also colonize water cooling system surfaces and some have been shown to promote legionella replication. Amoebae and other ciliated protozoa are natural hosts for legionella. Legionella multiply intracellularly within amoebae trophozoites.  Logionella pneumophila  is known to infect five different genera of amoebae, most notably  Hartmanella vermiformis  and Acanthamoeba. Legionella can also multiply within the ciliated protozoa, Tetrahymena. Bacterial species that appear to provide legionella with growth promoting factors include Pseudomonas, Acinetobactor, Flavobacterium, and Alcaligenes. Copper ions are an effective method of control for each of these bacteria and protozoa. 
     The controlled release of copper ions has also been known to serve as an effective attachment and growth control for such marine organisms as algae, mussels, oysters and barnacles. Copper ions can eliminate and control algae, for example, by inhibiting photosynthesis which leads to its demise. And copper ions have been shown to be more lethal to the zebra mussel than other metal ions. For effective zebra mussel control in freshwater, for example, copper ion concentrations of eight parts per billion are estimated to be required, which is a level well below that recommended by the Environmental Protection Agency for freshwater aquatic protection. 
     The design of ion generators for salt water can generally be considered trivial. Due the high electrical conductivity of salt water, factors such as electrode spacing are not important. In fact, electrodes used in salt water application can be spaced many tens of centimeters apart without any consequential effect on system operation. Problems such as “bridging” of inorganic salts between the anode and the cathode, which leads to electrical shorting and conductivity stratification, are not a factor. The design and operation of copper ion generators in fresh water systems is consequentially different than the design employed in salt water systems. Simply put, the design and operational differences of salt water and fresh water copper ion generation systems are fundamentally related to the large differences, of several orders of magnitude, in electrical conductivity. Because of those differences, the present art employed in the design and operation of commercial copper ion generators for fresh water cooling systems has significant operational problems. In the experience of these inventors, users of present copper ion generators in industrial cooling water systems have reported problems such as bridging which leads to electrical shorting, electrical conductivity stratification which results in uneven electrode erosion, and plating of copper on the cathode. 
     Bridging, as previously described, occurs because of the necessity of placing the anode and cathode in close proximity to one another in fresh water systems. One way of dealing with this problem is to periodically reverse polarity of the electrodes. This solution, however, introduces system inefficiencies due to the fact that polarity reversal renders the system non-functional for the period of time that polarity is reversed. Uneven electrode erosion due to electrical conductivity stratification occurs for the reason that nonuniform water flow occurs between electrodes. In present designs, the velocity of the water which flows between the electrodes is not generally constant over the electrode face. This leads to stratification of inorganic materials in the water which, in turn, produces electrical conductivity stratification. Finally, plating of the metal anode material on the cathode, as previously mentioned, completely defeats the purpose of the ion generator in the present application. When plating occurs, the metal ions are deposited on the cathode rather than being introduced into flow stream that is to be treated. In the experience of these inventors, each of these problems is related to water flow and to electrode spacing, which is required to be very close in fresh water systems when compared to systems designed for use in salt water. The spacing of the electrodes in close proximity to each other in fresh water systems is required if power system expectations are to be within reason, on the order of a few hundred watts. The system simply will not be economical if maximum power requirements exceed several kilowatts. 
     SUMMARY OF THE INVENTION 
     It is, therefore, a principal object of this invention to provide a new, useful, and uncomplicated method and apparatus for exposing the water flow within a water system to an ion generation device wherein water velocity is increased between the electrodes of the ion generator. It is another object of this invention to provide such a method and apparatus where a tangential inlet is provided to create a high velocity vortex flow within the system in the vicinity of the ion generator electrodes. It is yet another object to provide such a method and apparatus which avoids “dead zones,” or areas where water velocities in the vicinity of the ion generator electrodes are low. It is still another object of the present invention to provide such a method and apparatus in which the aspect ratio (i.e., the ratio between the system inlet and the system containment tank diameter) is defined to lock on to a water flow velocity range which must be maintained for proper system operation and in which the residence time of flow within the system is similarly defined and maintained. It is still another object to provide such a method and apparatus in which a non-electrical conducting head is used to mount the electrodes of the ion generator and where a plurality of cooperatively alternating anodes and cathodes may be used. It is yet another object of the present invention to provide such a method and apparatus in which an automatic discharge valve is provided to control the system water level within the ion generator thereby maintaining a minimum vertical velocity, within the system. It is still another object to provide a self-cleaning elliptical or conical base to the flow tank. It is yet another object to provide such a method and apparatus wherein a sight glass is utilized to allow for visual inspection of anode wastage. It is still another object to provide such a method and apparatus wherein performance is optimized while manufacturing costs are not increased significantly. 
     The present invention has obtained these objects. It overcomes the aforementioned problems and disadvantages by providing a method and apparatus in which water flowing through a water system is vigorously and turbulently exposed to a plurality of electrodes of an ion generator whereby ions which are generated are fed into the water flow to prevent fouling of the water system by algae, nuisance invertebrates, microorganisms, and inorganic salts. The present invention accomplishes this by providing an ion generator having a self-contained tank through which the water flows. The generally cylindrical containment tank includes a tangential inlet pipe at the uppermost portion of the tank. An elliptical tank base includes an outlet pipe in combination with a tank clean out device at the lowermost portion of the tank. An aspect ratio, inlet pipe diameter versus containment tank diameter, is defined to achieve optimum ionization. A tank cover is provided which serves as the non-electrical conducting head for a plurality of electrodes which extend downwardly from the underside of the cover. When the tank cover is in place in its normal operating position, the electrodes are suspended from the tank cover within the containment tank. The electrodes are functionally configured, both in size and placement, to maximize water flow between them. The rate of water flow within the containment tank is defined such that residence time of flow within the tank likewise optimizes water ionization. A sight glass is provided within the containment tank to allow for visualization and monitoring of the container contents, and in particular anode wastage or wear, during operation. The foregoing and other features of the method and apparatus of the present invention will be apparent from the detailed description which follows. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front and top perspective view of a water system fouling control apparatus constructed in accordance with the present invention. 
     FIG. 2 is a partially sectioned front, top and right side perspective view of the water system fouling control apparatus shown in FIG.  1 . 
     FIG. 3 is an enlarged front elevational view of the water system fouling control apparatus shown in FIG.  1 . 
     FIG. 4 is a top plan view of the water system fouling control apparatus shown in FIG.  3 . 
    
    
     DETAILED DESCRIPTION 
     Referring now to the drawings in detail, wherein like numerals represent like elements throughout, FIG. 1 illustrates a preferred embodiment of a device which utilizes the method and apparatus of the present invention. An ion generator assembly, generally identified  10 , includes a containment tank  12  which is generally cylindrical in physical configuration. The containment tank  12  includes an upper tank portion  14  and a lower tank portion  16 . Situated about the perimeter of the upper tank portion  14  is an upper tank flange  18 . Situated about the perimeter of the lower tank portion  16  is a lower tank flange  32 . In the preferred embodiment of the device of the present invention, the tank  12  is constructed of standard pipe having a  48  inch inner diameter. This dimension, though not significant in and of itself, is significant in view of other assembly dimensions which will become apparent later in this detailed description. 
     The containment tank  12  is supported about its outer perimeter by a plurality of support legs  44 , each support leg  44  being attached to the tank  12  by means of a support gusset  42 . Each leg  44  also includes a support foot  46  which rests upon a generally horizontal surface  88 . As shown in FIG. 4, three such legs  44  are illustrated. It is to be understood that more legs  44  could be utilized if such was desired or required, the number of such legs  44  not being a functional limitation of the present invention. 
     Attachable to the upper tank flange  18  is a tank cover or lid  20 . The lid  20  includes a lid perimeter  22 , a top lid surface  24  and a lid underside surface  26 . In the preferred embodiment, the lid  20  is constructed of a theroset plastic material which provides strength, durability and electrical nonconductivity. The significance of this electrical nonconductive, or electrical insulating, feature will become apparent later in this detailed description. The lid  20  is attachable to the upper tank portion  14  by means of a plurality of fasteners  86 , such as bolts, which are installed about the lid perimeter  22  and through the upper tank flange  18 . See FIG.  4 . Here again, the number of such fasteners  86  is not a functional limitation of the present invention. The number of fasteners  86  may be varied without deviating from the scope of this invention. The important feature of the fasteners  86  is that they prevent the lid  20  from coming away from the tank  12  and that they prevent rotation of the lid  20  about the tank  12 . 
     Attachable to the bottom tank flange  32  is an elliptical head  34  having a head flange  36 . In the preferred embodiment, the material and the diameter of the head  34  matches that of the tank  12 . The lowermost portion of the head  34  includes a centrally located bottom aperture  38 . Attached to the aperture  38  is a bottom flange  40 . Attached to the bottom flange  40  is an elbow  48  which includes a first flange  92 , a clean-out  94 , and a second flange  96 . Attached to the second flange  96  is a discharge pipe  98  through which tank discharge flow  8  is accomplished. 
     The upper tank portion  14  also includes an inlet pipe  30  which provides a continuum with the interior  80  of the containment tank  12 . As shown, the flow path  2  through the inlet pipe  30  is generally tangential to the tank interior  80 . In the preferred embodiment, the inner diameter of the inlet pipe  30  is 4 inches. In this fashion, the tank  12  diameter to inlet pipe  30  diameter ratio is 12:1. The tank  12 , the elliptical head  34  and the inlet pipe  30  are fictionally cooperative to allow water flow  2  through the inlet  30 , into the tank interior  80  in a whirlpool-like or vortex flow  4 , and out the bottom aperture  38  of the head  34  in a discharge flow  6 . See FIGS. 2 and 3. The significance of this flow pattern will become apparent later in this detailed description. The containment tank  12  also includes a sight glass aperture (not shown) defined within the wall of the tank  12 . Attached to the aperture is a sight glass flange  82  and a sight glass  84 . The purpose of the sight glass  84  is to provide visual access to the tank interior  80 . As shown, the axis of the pipe  30  is parallel to the axis of the sight glass  84 . This general alignment is desirable in the preferred embodiment, but not absolutely critical. 
     Attached to the underside  26  of the lid  20  are a number of functionally cooperating electrodes  50 ,  60 ,  70 . As shown in the preferred embodiment, an anode  50 , a first cathode  60  and a second cathode  70  are provided. The anode  50  is effectively “sandwiched” between the cathodes  60 ,  70 . Although only a single anode  50  and a pair of cathodes  60 ,  70  are shown, it is to be understood that the number of such electrodes  50 ,  60 ,  70 , and the combination of them, is not a functional limitation of the present invention. Other combinations could be provided, such as two anodes and three cathodes or three anodes and four cathodes, and so on, without deviating from the scope of the present invention. As shown, the anode  50  and each cathode  60 ,  70  are each fabricated in the shape of a rectangular prism. In the preferred embodiment, the anode  50  is made of copper or silver and each cathode  60 ,  70  is made of stainless steel. Again, the material from which each of the electrodes  50 ,  60 ,  70  is made is not a limitation of the present invention, other than that the materials used must be functionally conducive to the process of electrolysis. The anode  50  includes a top anode portion  52 , a central anode portion  54 , a bottom anode portion  58 , and a pair of anode faces  56 , the anode faces  56  being generally parallel to one another and providing the greatest surface area of the anode  50 . Similarly, each cathode  60 ,  70  includes a top cathode portion  62 ,  72 , a central anode portion  64 ,  74 , a bottom anode portion  68 ,  78 , and a pair of anode faces,  66 ,  76 , respectively. The anode  50  is attached centrally to the lid underside  26  by means of a plurality of anode fasteners  102 . See FIG.  4 . Similarly, each cathode  60 ,  70  is attached to the lid underside  26  by means of a plurality of cathode fasteners  104 ,  106 , respectively. At the bottom portion  58  of the anode  50  and the bottom portions  68 ,  78  of each of the cathodes  60 ,  70 , respectively, is a stabilizing element  90 . The stabilizing element  90  is functionally adapted to maintain the electrodes  50 ,  60 ,  70  in substantially parallel planar relationship. In this parallel planar relation, the plane defined by each electrode  50 ,  60 ,  70  is substantially parallel to the axis of the inlet pipe  30 . See FIGS. 2 and 4. As shown, one of the anode fasteners  102  is attached to a positive electrical lead  112  through which an electrical current may flow. Similarly, one of the cathode fasteners  104 ,  106  attached to each of the cathodes  60 ,  70 , respectively, is attached to a negative, or grounding, lead  114 ,  116 . An electrical potential or voltage may be applied across the anode lead  112  and each of the cathode leads  114 ,  116 , and therefor across the anode  50  and each of the cathodes  60 ,  70 . In the preferred embodiment, a power supply on the order of several hundred watts may be applied to achieve the electrochemical process of electrolysis across the electrodes  50 ,  60 ,  70 . 
     In application, water flow  2  is initiated to the interior  80  of the tank  12  by means of the tangential inlet pipe  30 . In this fashion, water enters the tank interior  80  and follows the annular wall surface in a whirlpool-like or turbulent vortex-type fashion, These inventors have found that water inlet velocity should not be less than 5 feet per second. This water flow  4  allows water to pass around, over and between the generally parallel electrodes  50 ,  60 ,  70 . This turbulence facilitates the electrolysis process and the migration of metal ions away from the anode  50  and away from the cathodes  60 ,  70  before the metal ions have a chance to attach themselves to the cathodes  60 ,  70  thus defeating the purpose of ionic water treatment. These inventory have also found that “residence time,” or vertical flow between the anode  50  and either cathode  60 ,  70  should be not less than 0.5 seconds and not more than 2.0 seconds. The minimum vertical velocity between the anode  50  and either cathode  60 ,  70  is 2 feet per second. These inventors have also found that additional hydrodynamically designed vanes or other flow directing devices (not shown) could be added at the point where the inlet pipe  30  intersects the tank  12  to accentuate or enhance vortex flow  4  within the tank interior  80 . Similar devices may be installed at the discharge aperture  38  of the head  34  for the same purpose. The flow  4  continues about the electrodes  50 ,  60 ,  70  until the water flow  6  discharges through the head aperture  38 , the water being properly ionized at this point. The elliptical head  34  and the aperture  38  defined in it serves a “self-cleaning” function by discharging suspended solids contained within the flow stream  6 . The water ionization at this point of discharge serves to control algae, nuisance invertebrates, microorganisms and inorganic salts lurking in other parts of the water system within which the ion generator assembly  10  of the present invention is incorporated. As the electrolysis process continues, the anode  50  effectively becomes used up as ions are given up to the water flow  4 . The sight glass  84  allows the user to view the containment tank interior  80  to determine if anode wastage has occurred to the point that the anode  50  must be replaced. Replacement of the anode  50  is easily accomplished by removal of the tank lid  20 , detachment of the anode lead  112 , withdrawal of the anode fasteners  102 , insertion of a new anode  50 , replacement of the anode fasteners  102 , reattachment of the anode lead  1   12  and reseating of the lid  20 . 
     From the foregoing description of the illustrative embodiment of the invention set forth herein, it will be apparent that there has been provided a new, useful, and uncomplicated method and apparatus for exposing the water flow within a water system to an ion generation device wherein water velocity is increased between the electrodes of the ion generator; where a tangential inlet is provided to create a high velocity vortex flow within the system in the vicinity of the ion generator electrodes and which avoids “dead zones,” or areas where water velocities in the vicinity of the ion generator electrodes are low; where the aspect ratio (i.e., the ratio between the system inlet and the system containment tank diameter) is defined to lock on to a water flow velocity range which must be maintained for proper system operation and the residence time of flow within the system is similarly defined and maintained; where a non-electrical conducting head is used to mount the electrodes of the ion generator and where a plurality of cooperatively alternating anodes and cathodes may be used; where an automatic discharge valve is provided to control the system water level within the ion generator thereby maintaining a minimum vertical velocity within the system; where a self-cleaning elliptical or conical base to the flow tank is provided; and where a sight glass is utilized to allow for visual inspection of anode wastage.