Patent Publication Number: US-2011048964-A1

Title: Axial-sump electrolytic flow cell

Description:
RELATED APPLICATION 
     The present application claims the benefit of U.S. Provisional Application No. 61/181,980 filed May 28, 2009, and entitled “AXIAL-SUMP ELECTROLYTIC FLOW CELL”, which is incorporated herein in its entirety by reference. 
    
    
     FIELD OF THE INVENTION 
     The present invention relates to a device which treats fluid electrolytically, typically by generating gases and such that can be dissolved into the fluid. More specifically, the present invention relates to an electrolytic flow cell device having an improved design utilizing easily replaceable to components to promote ease of use and installation as well as reduced costs of operation. 
     BACKGROUND OF THE INVENTION 
     Electrolytic flow-through cells are used extensively in treating swimming pool water. In a pool installation, these electrolytic flow-through cells are utilized to generate chlorine from a chloride-based salt that is added to the water. When this salt containing water is passed through the electrolytic flow-through cell, the electrodes contained therein pass electrical current through the salt water passing from electrode to electrode. The resulting current flow generates chlorine, molecular oxygen, and molecular hydrogen. The electrodes can be made from any electrically conductive material but are frequently constructed of titanium due to its high resistance to corrosion. Additionally, the electrodes are typically coated with metallic oxides such as, for example, ruthenium, iridium, platinum, rhodium, and palladium that serve to reduce the oxidation of the titanium electrodes and augments the generation of gasses, oxidizing and reducing agents such as, for example, hydrogen peroxide, ozone, atomic oxygen, atomic hydrogen, hydrogen ions, and hydroxide ions. Absent this metallic oxide coating, the active surfaces of the titanium electrodes will oxidize and have a detrimental effect on the active surfaces until the titanium electrode is ineffective. Additionally, any uncoated or raw edges provide unwanted nucleation sites which precipitate scale. 
     Electrolytic flow-through cells similar to these pool devices have been developed to treat water to affect its potability. Various contaminants including metallic ions such as, for example, manganese, iron, arsenic, lead, chrome, aluminum, antimony, radium, and uranium, and other undesirable compounds such as, for example, hydrogen sulfides can be physically altered by interacting with electrolyzed fluids such that physical filtration can thereafter remove the contaminant. The list of known contaminants that can be successfully treated by this type of process continues to expand. Water sources which are desired to be used as sources of potable water have on average, significantly less dissolved solids, typically ranging from a conductivity of 100 to 1200 microsiemens, as compared to what is normally found in swimming pools. Also, the type of dissolved solids required for swimming pool water disinfection must contain chlorides and these are most often derived from using sodium chloride salt. Thus the chlorides are converted into chlorine-based disinfectants, while the sodium metals remain soft. Soft minerals do not destructively scale electrodes in the manner that hard minerals such as calcium and magnesium do. Also, chlorine compounds tend to assist in keeping the electrodes clean. Water sources, such as well water are mostly full of hard minerals without chlorine and therefore tend to cause significant scaling issues and can greatly degrade the long-term performance of these electrolytic flow-through cells. 
     While there are have been many different types of geometries available to arrange electrodes in a cell to treat a flow of aqueous fluid, the axial-flow variant is most common. Axial flow electrodes can typically take advantage of cylindrical conduits particularly when any significant pressure is present. Unfortunately, there are many disadvantages with a purely axial design such as, for example, small flow cross-sections, rectangular flow passageways, small aspect ratios, side electrical contacts, run-dry concerns, difficulty with electrode replacement, fluid mixing issues, compactness and materials of construction as detailed below. 
     Any fluid distribution system has conduit, i.e., pipes or tubing, which is selected for the required flow rate and having an acceptable pressure loss. For example, residential plumbing systems are typically ¾″ to 1″ in pipe size, which has an internal dimension (d) of 1″ or less. It is difficult to arrange electrodes inside a similarly sized residential plumbing system without reducing the net flow area and such arrangements typically require very long electrodes to gain the necessary surface area to conduct enough electrical current. These long electrode arrangements are often problematic in trapping scale and can become less efficient when large current densities coupled with low fluid flow rates aerate the electrode with excessive gas bubble formation. Therefore, electrolytic flow-cells which take advantage of properly sized electrodes generally reside in conduits having a significantly larger cross-sections. 
     The most practical method of manufacturing electrodes is in flat sheets of titanium. These sheets are then coated with iridium, ruthenium, platinum, rhodium, and/or palladium. After these metals are thermally bonded to the titanium, the flat sheets are then blanked into flat electrode shapes. The cell arrangement of flat blades which provides the best use of surface area is a parallel stack of blades with alternating polarities. For example, a cathode, anode, cathode . . . array of (n) blades of dimension (x) by (y) provides for a total active surface area of xy (n−1). While other flat and non-flat blade geometries are possible, the flat sandwich geometry is practical and is widely used in the industry. These sandwich type geometries almost always have a parallelogram cross-section. If the blade thickness is (t) and the interspacing between the electrodes is (s), then the dimension of the flow cross section width is x(tn+s(n−1)). The flow area therefore becomes xs(n−1). Lastly, it is advantageous to have flow area xs(n−1)&gt;π d 2 /4. For example, a square flow cross section of (9) blades each having a blade thickness (t) of 0.025″ thick requires an internal conduit size of at least 1.42 times larger than a 1″ internal diameter pipe to carry the required flow without any additional pressure drop. However, the chamber internal diameter should be even larger to accommodate any scale build-up. This means that a starting design point for an axial flow chamber must be a 1½″ pipe to be used with 1″ pipe systems. For this example, the blades would have a width (x) of 0.886″ with an internal spacing of 0.098″. 
     If the above example is expanded to create a typical axial-flow cell with a 80 sq. inch surface area, than the (9) blades would have n−1 or (8) active surface areas. 80/8=10″. Each blade is required to be 10″ long. The resulting aspect ratio is 0.886/10 or 0.089. This means that the blade is 11.28 times longer than it is wide or its width is 0.089 times its length. When the blades have aspect ratio smaller than about 0.25, there can be difficulty in dislodging scale during polarity reversals and excessive ventilation due to bubbles forming and keeping the downstream regions of the blades wet and conducting electrical current. For this reason, it is preferred to have shorter, wider blades than narrow longer blades. Creating a square cross section with a 0.25 aspect ratio is not possible with a small number of blades. If more blades are added, then the costs of the blades and connection hardware multiply accordingly. In order to optimize economics, it is desirable to keep the blade count as small as possible. 
     Given a purely axial-flow electrode design, it is necessary for the electrical contact to exit 90 degrees from the flow axis. Such cross connections are not advantageous to economic blade manufacturing and they necessarily complicate chamber design. Any side opening in a conduit is a potential cause of structural concerns and requires gaskets, potting agents, caps, or suitable secondary conductors. Any time the electrical connection is made internal to the chamber, the metals must be the very same material or galvanic corrosion will rapidly degrade the contacts. Also, to achieve a robust electrical connection, any active coatings on the electrodes should be removed to get to un-oxidized base metals. For example, if an electrode is made from titanium with an iridium oxide coating, then the coating should be removed and a suitable titanium connector must be joined gas-tight to effect a solid connection. This is not only expensive in terms of material and parts but also in assembly labor. This also creates a joint which is inferior to passing an integral blade tab through the side of the conduit. 
     Operation of axial-flow chambers in a horizontal manner can subject them to partial-flow conditions when the fluid flow rate is less than maximum and/or there is entrapped air resulting in the electrodes being only partially wet. Partial-flow conditions do not promote efficient operation and can reduce the net effectiveness of the electrolytic flow-through cell. If axial flow chambers are used in a vertical pipe run, then the fluid can either be flowing upward, or downward. In a downward flow condition, the fluid can simply drop down the pipe and not even fill the chamber allowing it to run dry. The only effective orientation for an axial-flow chamber is vertical up-flow. However, such a vertical up-flow orientation can often require special modifications to the existing piping scheme and may not be suitable for many applications. 
     With respect to electrode replacement, use of an axial flow design can necessitate the placement of a large access port on the conduit. Alternatively, the entire axial-flow chamber can be designed to be removed from the piping/tubing scheme. 
     Electrolyzed water is more effective in treating the contaminants in the fluid if there is some type of mixing that can transpire as close to the actual electrolysis as possible. When the mixing occurs in the direct vicinity of the electrodes, mixing features can result in the formation of flow eddies. These turbulent non-laminar flow conditions can greatly augment the formation of scale, particularly on the flow-disturbing feature itself. Scale which develops on these flow disturbing features will grow rapidly and soon completely occlude the chamber. Therefore, traditional axial-flow chambers should have perfectly laminar flow conditions in the direct regions of the electrodes. If the fluid is to be mixed, it should therefore be done after the chamber and thus requires additional system length, complexity, and can result in unwanted pressure drops. 
     It is often desirable to keep any fluid system component compact to enable it to be easily adapted into the plumbing system or flow apparatus. Axial-flow chambers are the longest type of electrode system and require the most space for their operation. 
     With respect to materials of construction, ABS, PVC, and PPO are commonly used in water treatment devices. These materials are resistant to the typical concentrations of chemicals found and used in potable water and are also structurally sound and economic to use. These materials exhibit a high surface energy to enable adhesives bonding, particularly where an electrode tab exits the housing wall. Many structural potting agents can make hermitic long-term bonds to these plastics. Unfortunately, electrolytic cells fabricated with these materials tend to enable the precipitation and adherence of scale. Scale tends to precipitate when these plastic materials are in close proximity to the electrical field of the electrodes. Once scale begins to adhere to the plastic material, the scale continues to rapidly build and eventually grows to plug the chamber resulting in increased back pressure and reducing or eliminating fluid flow. Scale in contact with these plastic materials is not able to be dissolved by the operation of anodic acid production during electrolysis. Polarity reversal is only marginally helpful at preventing, controlling, or removing scale formations remotely located from the surface of the electrode. 
     There are materials which are better at preventing the adherence or precipitation of scale deposits. There are materials which discourage the formation of scale such as acrylic, polycarbonate, polysulfone, and polyethylene. Unfortunately, acrylic is to brittle for structural integrity during pressure cycles, polycarbonate has poor chemical resistance to chemicals used with potable water, and polysulfone is expensive. Polyethylene has many attractive benefits, low cost, high chemical resistance, low scale build, very fatigue resistant and it is easy to mold. Unfortunately, PE has very low surface energy and therefore it is very difficult to use potting agents such as epoxy and the like to create a long-term hermitic bond to seal integral electrode conductors through the housing wall. PE is also a poor material to use with high-pressure because of excessive elongation, flexing and creep in moderate to high stress applications. 
     As discussed above, current designs of axial-flow style electrolytic flow-though chambers suffer a variety of problems that can lead to inefficiency and increased operational costs. As such, it would be beneficial to have new designs for electrolytic flow-through chambers that overcome the limitations of current devices. 
     SUMMARY OF THE INVENTION 
     The present disclosure is directed to an electrolytic cell for operation in low to medium conductivity hard water that can keep its electrode scale free for an extended life cycle before maintenance. In view of the aforementioned issues with the current design of electrolytic flow-through cells, it is the intent of this invention to define multiple improvements to the existing designs. As part of this invention, an improved electrolytic cell will generally include easily replaceable components providing for ease of maintenance, low-cost replacement, and the lowest impact to the environment for the service life of the system. A representative axial-flow sump design of the present invention provides for a solution to all of the previously stated shortcomings of existing axial-flow systems. In general, the axial-flow sump system can comprise a replaceable electrode cartridge that is housed in a sump. In one representative embodiment, the replaceable electrode cartridge comprises a quarter-turn bayonet type electrode cartridge for replaceable mounting in the sump. 
     In a preferred embodiment of an axial-flow sump cell, the fluid flow path is arranged to allow fluid entry perpendicular to a main flow axis at a top of the sump and then allowing the fluid to flow axially downward thereafter to exit inline with the major flow axis. The major flow axis is defined as a vertical line centered about the middle of the electrode array. When the fluid flow is allowed to enter on the side of the electrode array, the problems of inlet flow area cross-section are avoided and can be made much larger without impacting the diameter of any conduit diameter. The inlet cross-section is no longer defined by the limitations of traditional axial-flow cell geometry, but can take advantage of additional flow area on the side of the electrodes. The exit flow can be in-line with the major flow axis, perpendicular to it, or vented out both sides as desired thereby increasing flow cross-section as desired. 
     In an embodiment of the axial-flow sump cell, the electrodes are arranged in a traditional alternating parallel array and as such result in a rectangular flow cross section on a plane perpendicular to the major flow axis. When an electrode pack is immersed into a sump, the issues of creating a rectangular flow passageway which is suitable as a hydraulic super structure are no longer necessary as the sump provides ample volume to house the rectangular flow passageways without impacting the housing geometry. Also, the sump and head can be optimized for hydraulic structural integrity. The uses of a round sump and head are divorced from and have no impact on the shape of the removable electrode cartridge. 
     In a representative embodiment, a sump and head can be made of sufficient size to allow for large electrode widths and short lengths independent from the normal constraints of traditional axial-flow cell design. The aspect ratio of the present axial-flow sump electrode can be better than 0.25. Also, sump length can be increased to allow a variety of different electrode cartridges, each having differing amounts of surface area, blade spacing, and coatings as desired for various functions. In one presently contemplated embodiment, an electrode can be 5.25″ long by 1.50″ wide to provide an aspect ratio of 0.29 (1.50/5.25=0.29). This means that the electrode is only 3.5 times as long as it is wide which shortens the length that scale needs to be scavenged and limits the size of the resulting bubble formations as they coalesce and grow along the blade. Smaller bubbles dissolve into the fluid faster and more efficiently then larger ones. Also, a shorter electrode tends to get less ventilated at low fluid flow rates and can thereby remain wetted and operational during electrolysis. 
     In another embodiment, the axial-flow sump of the present invention allows for electrodes to be fabricated with integral conductor tabs extend outward in line with a major flow axis. Such an orientation allows the electrodes to be easily fashioned into a removable cartridge having a round sealing means such as, for example, a gasket or o-ring style seal. This round sealing means enables rotary motion to be utilized in facilitating installation and removal of an electrode cartridge. In some embodiments, the electrode cartridge can comprise at least one bayonet tab that serves to engage the cartridge with a sump to provide a secure connection during operation and to facilitate removal via rotation of the electrode cartridge with respect to the sump. The electrode cartridge can also rotatably connect to the sump using other attachment means such as, for example, threads, or through suitable axial attachment means including quick-connect style connections. 
     Another aspect of the axial-flow sump of the present invention is that sump geometry insures immersion of electrode packs in a volume of fluid at all times. The nature of the sump is such that gravity always keeps the sump filled with fluid so that there is no condition in which the electrodes will be in operation without fluid being present. In the event that the fluid flow rate is very low, the fluid in the inlet and exit conduits can be in a partial flow condition. Even in this partial flow condition, the design of the sump still provides sufficient fluid volume to keep the majority of the electrode immersed and therefore operable. 
     In another aspect of the present disclosure, an axial-flow sump features a removable electrode pack or electrode cartridge. Electrodes can be easily disconnected from an electrical connection via a plug if desired, or alternatively, wires can be potted into the electrode cartridge as desired. In one embodiment, a power plug is attached to the electrode cartridge as it can reduce manufacturing and consequently, replacement cost of the replaceable electrode cartridge. Further, the removable electrode cartridge can be divorced from any additional electrical control or monitoring instrumentation such as temperature, pressure, and flow transducers that can be integral to a sump or within a flow system. By separating the removable electrode cartridge from any control or monitoring function, there exists no requirement for circuitry such as printed circuit boards, lights, or similar elements to be integrated into the removable electrode cartridge. As such, the design of the removable electrode cartridge can be optimized for the electrodes and without sacrificing electrode performance so as to accommodate system control or monitoring. In general, the replacement cost of this removable electrode cartridge is reduced as there is little additional material than the electrode blades themselves. As the electrodes are the elements that require the most maintenance due to their tendency to foul with mineral scale, the removable cartridge can be easily removed and placed into a suitable cleaning fluid such as muriatic acid without worry that something will be damaged. In the event that the precious metal coating on the electrode has worn off due to long-term use, replacement of the removable electrode cartridge is fast and easy and can be done without specialized tools or the need for service technicians. In addition, a removable cartridge can be small in size so as to generate minimal material waste for environmentally conscious recycling. 
     In another aspect of the present disclosure, axial flow-sump geometry as disclosed provides the advantage of mixing evolved gas bubbles into a fluid stream to promote oxidation/reduction of contaminants contained in the fluid stream. A treated fluid stream exits the bottom of the electrodes and then is forced to take a 180 degree directional change in a large flow cross-section so as to limit any resulting back pressure. The treated fluids can remain in contact for additional time as they mix within the sump and precipitate contaminants before being collected into the exit port for subsequent filtration. The nature of a vertically descending fluid flow and open bottom electrode array is that gravity can assist any precipitated solids to drop clear of the electrodes and fall to the bottom of the sump. When the flow rate is elevated, these solids can be fluidized and swept out of the sump to be captured in the filter. 
     In another aspect of the present disclosure, an axial-flow sump architecture takes advantage of a vertical electrode that can be housed in sump of any length with horizontal inlet and outlet connections. A resulting horizontal run between the inlet and outlet connection is kept substantially short to allow for easy connection with a horizontal conduit scheme. The axial-flow sump architecture is both easy to connect to an existing piping system and correspondingly difficult to install in an incorrect or unadvantageous orientation unlike traditional axial-flow systems. While the axial-flow sump architecture tends to emphasize fluid flow in a single direction, the fluid flow can also be reversed if desired without impacting performance of the axial-flow sump. 
     In another aspect of the present disclosure, it can be advantageous to use polyethylene in close proximity to the electrodes due to the polyethylene&#39;s resistance to scale formation. However, as the polyethylene is not a good choice for a hermetic blade conductor seal or a structural housing, polyethylene can be used as a sleeve or shroud to surround the electrodes. While using polyethylene as a sleeve or shroud around the electrodes, a main structural element of electrode cartridge can be made from a non-conductive material such as ABS, PVC, and PPO to meet structural requirements. Electrode conductors can be passed through appropriate molded or otherwise formed apertures and potted with traditional agents such as, for example, urethane, epoxy, or acrylic. The electrodes can be surrounded by a thin shroud of polyethylene or material exhibiting similar properties including resistance to scale formation while remaining free from the structural strength and hermetic sealing requirements of the main structural element of the electrode cartridge. Anywhere there is an electrical field or ionic activity on or near the electrodes, materials necessary for supporting the electrodes and controlling the flow path therefrom can be made from polyethylene to reduce scale buildup. When the electrodes are surrounded by a sleeve or shroud, it is generally desirable to provide for a sleeve or shroud shape that forces all of the fluid to be treated into a region between an anode and cathode. Any fluid forced to pass between a cathode and anode will have the best possible interaction with high-energy oxidation and reduction activity proximate to active electrode surfaces 
     In another aspect of the present disclosure, an electrode can be fabricated such that any region of the electrode which is not active such as, for example, the edges can be covered by a material which shields the inactive edge from a fluid stream or alternatively, the edges can be activated by coating them with precious metals that prevent the base titanium from becoming oxidized and/or causing scale build-up. Since it is often labor intensive and expensive to coat electrodes with these precious metals such as iridium, ruthenium, palladium, rhodium, and platinum, it is desirable to stamp the profile of the electrode after it has been coated with these precious metals. Careful arrangement of the electrode design can allow for an exit edge to remain coated after blanking the coated sheet. With the exit edge coated, the only other exposed edge of the electrode not in contact with a polyethylene shroud is an inlet edge which can have a suitable inlet grate fashioned so as to cap the inlet edge. 
     In yet another aspect of the present disclosure, a removable electrolytic cartridge can be mounted within a flow system with a means for mounting. In one embodiment, the means for mounting can comprise a sump head such an electrode assembly is positioned within an attached sump chamber. Alternatively, the means for mounting can comprise a cartridge fitting such as, for example, an elbow, “T” or other port assembly for mounting the electrode assembly directly within a length of conduit for inline operation. 
     The above summary of the invention is not intended to describe each illustrated embodiment or every implementation of the present invention. The Figures and the Detailed Description that follow more particularly exemplify these embodiments. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       The invention can be more completely understood in consideration of the following detailed description of various embodiments of the invention in connection with the accompanying drawings, in which: 
       FIG. is a rear, perspective view of a representative axial-flow sump electrolysis chamber according to an embodiment of the present disclosure. 
         FIG. 2  is a side view of an outlet side of the axial-flow sump electrolysis chamber of  FIG. 1 . 
         FIG. 3  is a section view of the axial-flow sump electrolysis chamber of  FIG. 1  taken at line A-A of  FIG. 2 . 
         FIG. 4  is a top view of the axial-flow sump electrolysis chamber of  FIG. 1 . 
         FIG. 5  is an exploded, top perspective view of an axial-flow sump and a removable electrode cartridge according to an embodiment of the present disclosure. 
         FIG. 6  is a rear, perspective view of the axial-flow sump electrolysis chamber of  FIG. 1  with a plug assembly shown detached from a removable electrode cartridge according to an embodiment of the present disclosure. 
         FIG. 7  is a rear, perspective view of the axial-flow sump electrolysis chamber of  FIG. 1  with a sump housing shown detached from a sump head according to an embodiment of the present disclosure. 
         FIG. 8  is an exploded, perspective view of a representative embodiment of a removable electrode cartridge according to the present disclosure. 
         FIG. 9  is a section view of the axial-flow sump electrolysis chamber of  FIG. 1  taken at line B-B of  FIG. 4 . 
         FIG. 10  is a section view of axial flow sump electrolysis chamber of  FIG. 1  taken at Detail C of  FIG. 9 . 
         FIG. 11  is a bottom, perspective view of a representative embodiment of a removable power plug according to the present disclosure. 
         FIG. 12  is an exploded, top perspective view of a flow assembly for mounting a removable electrolytic cartridge directly within a fluid conduit according to an embodiment of the present disclosure. 
     
    
    
     While the invention is amenable to various modifications and alternative forms, specifics thereof have been shown by way of example in the drawings and will be described in detail. It should be understood, however, that the intention is not to limit the invention to the particular embodiments described. On the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. 
     DETAILED DESCRIPTION OF THE DRAWINGS 
     Referring to  FIGS. 1 ,  2 ,  4 ,  6 ,  7 , a representative embodiment of an axial-flow electrolytic cell  100  generally comprises a sump assembly  102 , a removable electrolytic cartridge  104  and a plug assembly  106 . Axial-flow electrolytic cell  100  is generally mountable within a fluid flow system by coupling the sump assembly  102  to a flow inlet line  108  and a flow outlet line  110 . In a preferred embodiment, flow inlet line  108  and flow inlet line  110  are aligned in a generally axial orientation. 
     As illustrated in  FIGS. 3 ,  7  and  9 , sump assembly  102  generally comprises a sump head  120  and a sump chamber  122 . Sump head  120  generally includes a head body  124  having a sump mounting width  125 . Head body  124  includes an inlet flow port  126  and an outlet flow port  128 . Sump head  120  can include one or more connectors  129  for retainably engaging the flow inlet line  108  to the inlet flow port  126  and the outlet flow line  110  to the outlet flow port  128 . Connector  129  can comprise a u-clip retention feature to enable fittings for PVC, pipe, copper, or PEX tubing as desired for easily removable connections that are free of stresses. The head body  124  can comprise a head perimeter wall  130  having an upper perimeter portion  132  and a lower perimeter portion  134 . A lower head flange  136  is defined at the interface between the upper perimeter portion  132  and the lower perimeter portion  134 . The lower perimeter portion  134  can include a lower exterior thread  136 . The head perimeter wall  130  defines an upper head surface  138  and a lower head surface  140 . A cartridge aperture  142  extends continuously between the upper head surface  138  and the lower head surface  140 . Surrounding the cartridge aperture  142  on the upper head surface  138  is an upper recess  144 . A capture plate  146  can be mounted within the upper recess  144  using fasteners  148 . Sump head  120  generally comprises a molded assembly formed of a suitable polymer material such as, for example, ABS, PVC, and PPO and the like. 
     Sump chamber  122  can have a generally cylindrical perimeter wall  150  defining an internal sump volume  152 . The cylindrical perimeter wall  150  extends between an upper chamber surface  154  and a lower chamber surface  156 . A chamber opening  158  is defined at the upper chamber surface  154 . Proximate the upper chamber surface  154 , the sump chamber  122  can include an internal chamber thread  160 . Sump head  120  comprises a molded assembly and can be formed of a suitable polymer material including, for example, ABS, PVC, and PPO and the like. In one preferred embodiment, sump chamber  122  is molded of a transparent polymer such that fluid flow can be viewed through the cylindrical perimeter wall  150 . 
     Referring to  FIGS. 5 and 8 , removable electrolytic cartridge  104  generally comprises a cartridge head  170 , an electrode sleeve  171  and an electrode assembly  172 . Cartridge head  170  has a mounting body  174  defining an upper cartridge surface  176 , a perimeter cartridge surface  178  and a lower cartridge surface  180 . Projecting outwardly from perimeter cartridge surface  178  is one or more cartridge attachment tabs  182 . Perimeter cartridge surface  178  can further comprise a cartridge sealing groove  184  for accommodating a cartridge sealing member  186 . Perimeter cartridge surface  178  defines a cartridge inlet  188 . A connection recess  192  is formed within the upper cartridge surface  176 . Lower cartridge surface  180  can comprise one or more cathode apertures  194  and one or more anode apertures  196  that extend into the connection recess  192 . 
     Electrode sleeve  171  generally comprises a rectangular perimeter  200  that resembles the size and shape of electrode assembly  172 . Electrode sleeve  171  includes a hollow sleeve interior  174  that extends between an upper sleeve surface  202  and a lower sleeve surface  204 . Proximate the upper sleeve surface  202 , electrode sleeve  171  includes a sleeve inlet aperture  206 . 
     As illustrated in  FIGS. 8 ,  9  and  10 , electrode assembly  172  generally comprises a stacked arrangement of individual electrode blades  210 . Each individual blade  210  includes a conductor end  212  with a cathode  214  and an anode  216 . The arrangement of the individual cathodes  214  and electrodes  216  is alternated with each individual electrode layer. Each electrode blade  210  has an electrode length  218  and an electrode width  220 . In order to promote efficiency, an aspect ratio defined as electrode width  220  divided by electrode length  218  can be greater than 0.25. In one representative embodiment, each individual blade  210  can have electrode length  218  equal to 5.25″ with electrode width  220  being equal to 1.50″ to provide an aspect ratio of 0.29 (1.50/5.25=0.29). In this embodiment, electrode blade  210  is approximately 3.5 times as long as it is wide which shortens the length along the electrode blade  210  that scale needs to be scavenged and limits the size of the resulting bubble formations as they coalesce and grow along each electrode blade  210 . Each electrode blade  210  generally comprises a titanium based coated with a precious metal such as, for example, iridium, ruthenium, palladium, rhodium, and platinum. Preferably, electrode length  218  exceeds the sump mounting width  125  so as to increase the amount of the exposed electrode surface beyond the space required for mounting the axial-flow electrolytic cell  100  within a flow system. 
     Generally, removable electrolytic cartridge  104  is fabricated by molding the cartridge head  170  of a non-conductive polymer material such as, for example, ABS, PVC, and PPO. For compatibility purposes, it can be advantages to mold the cartridge head  170  and sump head  120  of the same material. Due to its proximity to the electrode assembly  172 , electrode sleeve  171  is preferably molded of a scale-resistant polymer such as, for example, polyethylene. Electrode assembly  172  is attached to the cartridge head  170  by inserting the cathodes  214  and anodes  216  on conductor end  212  into the corresponding one or more cathode apertures  194  and one or more anode apertures  196  on lower cartridge surface  180  such that cathodes  214  and anodes  216  are exposed in connection recess  192 . The cathodes  214  and anodes  216  can be potted with an appropriate potting agent such as epoxy, urethane, or acrylic. In some embodiments, cathodes  214  and anodes  216  can be insert molded into the cartridge head  170 . Electrode sleeve  170  can be slidably advanced over the electrode assembly  172  such that upper sleeve surface  202  engages the lower cartridge surface  180  and sleeve inlet aperture  206  aligns with cartridge inlet  188 . The edges of each electrode blade  210  can be in direct contact with the electrode sleeve  171  such that no flow disturbances are created in the region of the electrode blades  210  so as to avoid turbulent flow and potential scale precipitation. It is also possible to have the edges of the electrode blades  210  spaced a small distance from the interior walls of the electrode sleeve  171  as long as the edges are masked by a suitable coating such as the precious metals of iridium, ruthenium, palladium, rhodium, and/or platinum. This small spacing or gap will also reduce the interaction of materials from precipitating or collecting and scale buildup. Alternatively, the edges can be coated in a material which prevents fluid contact such as a plastic or glass insulator. 
     Referring to  FIG. 11 , plug assembly  106  generally comprises a plug body  230  and a plug wire  232 . Plug body  230  has a plug perimeter wall  234 , an upper plug surface  236  and a lower plug surface  238 . Lower plug surface  238  includes one or more electrical contacts  240  for engaging and supplying power to cathodes  214  and anodes  216 . Plug body  230  is constructed such that plug perimeter wall  234  substantially resembles the shape of connection recess  192  such that plug body  230  is slidably insertable and snugly retained within the connection recess  192 . With plug body  230  retained within connection recess  192 , electrical contacts  240  are electrically engaged to cathodes  214  and anodes  216 . The plug assembly  106  has a 3×2 conductor array to connect to (5) separate electrodes; (2) anodes  216  and (3) cathodes  214 . It should be understood that during polarity reversal schemes, the electrodes are constructed and coated with identical materials such that anode  216  can become cathode  214  as the voltage and current are reversed for scale cleaning. The plug can be configured symmetrically for an even number of electrodes, or asymmetrical as desired to fit any electrode geometry. While plug assembly  106  provides for easy and quick replacement of removable electrolytic cartridges  104 , some embodiments of cartridge head  170  can include the plug wire  232  and electrical contacts  240  formed as integral components of the cartridge head  170 . 
     Generally, axial flow electrolytic cell is assembled by first assembling the sump assembly  102 , attaching the removable electrolytic cartridge  104  and finally connecting the plug assembly  106 . To assembly the sump assembly  102 , the sump chamber  122  is positioned such that the upper chamber surface  154  is proximate the lower perimeter portion  134  of the sump head  120 . The lower perimeter portion  134  is inserted into the chamber opening  158  such that the lower exterior thread  136  engages the internal chamber thread  160 . By rotating the sump chamber  122  relative to the sump head  120 , the lower exterior thread  136  and the internal chamber thread  160  interface and engage to retainably connect the sump head  120  and sump chamber  122 . As the sump head  120  and sump chamber  122  are connected, a sump seal member  240  can be compressed between the lower perimeter portion  134  and a thread flange  242  proximate the internal chamber thread  160  to prevent leakage under typical operation pressures. 
     Once the sump assembly  102  is sealably connected, the removable electrolytic cartridge  104  can be coupled to the sump head  120 . Removable electrolytic cartridge  104  is arranged such that lower sleeve surface  204  is proximate the cartridge aperture  142  as seen in Figure XX. Electrode sleeve  171  is advanced through the cartridge aperture  142  such that lower sleeve surface  204  enters the internal sump volume  152 . Cartridge head  170  is constructed such that mounting body  174  fits snugly within the cartridge aperture  142 . As lower sleeve surface  204  approaches the lower chamber surface  156 , cartridge sealing member  186  is compressed against the sump head  120  to provide a liquid tight seal under typical operating pressures. Lower sleeve surface  204  is spaced apart from the lower chamber surface  156  with enough clearance to hold any temporary scale which might collect during operation at low flow rates. Cartridge attachment tabs  182  enter the cartridge aperture  142 , whereby a turn of the removable electrolytic cartridge  104  results in the positive capture of the cartridge attachment tabs  182  below the capture plate  146 . With the cartridge attachment tabs  182  positioned below the capture plate  146 , the removable electrolytic cartridge  104  is retainably coupled to the sump assembly  102 . In a preferred embodiment, the cartridge attachment tabs  180  and capture plate  146  define a bayonet style capture mechanism where a quarter turn of the removable electrolytic cartridge  104  results in successful engagement of the removable electrolytic cartridge  104  and the sump assembly  102 . In some embodiments, cartridge aperture  142  can include one or more kick-off ramps to allow for a camming action as the cartridge attachment tabs  182  engage the capture plate  146 . One particular benefit of straight attachment tabs  182  as opposed to threads is that any pressure which would push outward on the removable electrolytic cartridge  104  does not result in back-driving of the removable electrolytic cartridge  104  and potential disconnection at operating pressures. In the event that a removable electrolytic element  104  has reached the end of it useful service life, removal is the reverse of the installation and a second, identical removable electrolytic element  104  can be installed to continue operation. 
     Once the removable electrolytic cartridge  104  is attached to the sump assembly  102 , the plug assembly can be attached to the removable electrolytic cartridge  104  by positioning the plug body  230  within the connection recess  192  with the lower plug surface  238  arranged such that electrical contacts  240  are electrically engaged to cathodes  214  and anodes  216 . Finally, plug wire  232  can be coupled to a power source such that power can be supplied to the electrode assembly  172  and electrolysis can be accomplished along electrode blades  210 . 
     Generally, axial-flow electrolytic cell  100  is installed within a fluid system by coupling flow inlet line  108  to an inlet conduit and the flow outlet line  110  to an outlet conduit. A fluid stream  300  to be treated enters the inlet line  108 , flows though the inlet flow port  126  and into the cartridge inlet  188  as illustrated in  FIG. 3 . From cartridge inlet  188 , fluid stream  300  is directed into the electrode sleeve  171  though the sleeve inlet aperture  206 . Once inside the electrode sleeve  171 , fluid stream  300  is directed downwards along electrode blades  210  where electrolysis and the generation of oxygen and hydrogen bubbles occur. Fluid stream  300  flows along the major axis or electrode length  218  and is forced between the individual electrode blades  210  such that the fluid stream  300  is fully exposed to the electrical influence of the electrolytically generated oxidation and reduction activity. Fluid steam  300  is bounded by the sides of each electrode blade  210  and the electrode sleeve  171 . Fluid stream  300  exits electrode sleeve  171  at the lower sleeve surface  204  and is forced to make a 180 degree toroidal turn which serves to mix the fluid stream  300 . Within the sump chamber  122 , the fluid stream  300  experiences additional contact time with the electrolytically generated gases oxygen until the fluid stream exits the sump chamber  122  through the outlet flow port  128  and out the flow outlet line  110 . After fluid stream  300  is treated by the axial-flow electrolytic cell  100 , the fluid stream  300  can be directed to points of use or through additional filtering means to remove any precipitated contaminants resulting from the electrolysis reactions. If during operation, scale begins to accumulate within the sump chamber  122 , the axial-flow electrolytic cell  100  can be backwashed with fluid stream  300  running in a reverse direction to remove scale. 
     With the rotatably connectable design of axial-flow electrolytic cell  100 , it will be understood that various capacity modifications can be made without substantially altering the system design. For instance, sump chamber  122  can be replaced with second sump chamber  122  having a similar diameter but a longer overall sump to increase the internal sump volume  152 . With a large internal sump volume  152 , a second removable electrolytic cartridge  104  having an electrode assembly  172  with electrode blades  210  having an increased electrode length  218  can be attached to the sump head  120 . In this manner, capacity or electrolytic performance can be varied without impacting connection of the sump head  120  or the plug assembly  106 . 
     Referring now to  FIG. 12 , removable electrolytic cartridge  104  can be employed directly within a fluid conduit as part of an inline flow system  400 . Generally inline flow system  400  comprises an upstream fluid conduit  402 , a downstream fluid conduit  403 , a cartridge fitting  404 , the removable electrolytic cartridge  104  and the plug assembly  106 . As shown in  FIG. 12 , cartridge fitting  404  can comprise an orientation that allows the electrode sleeve  171  to be positioned directly within a conduit flow stream so as to provide the benefits of electrolysis directly within the flow stream and the conduit. In some embodiments, cartridge fitting  404  can comprise an elbow body  406  having an elbow inlet  408  and an elbow outlet  410 . Alternatively, cartridge fitting  404  can comprise other suitable configurations including, for example, T&#39;s, and various pipe port designs. The elbow body  406  comprises a mounting surface  412  including a cartridge attachment aperture  414 . A retention plate  416  can be mounted to the mounting surface  412  with fasteners  418 . The removable electrolytic cartridge  104  is attached to the cartridge fitting  404  in the same manner as removable electrolytic cartridge  104  was attached to the sump head  120 . Specifically, the electrode sleeve is slidably inserted into the cartridge attachment aperture  414  such that the electrode sleeve  171 , and consequently, the electrode assembly  172  is positioned directly within the upstream fluid conduit  402 . Use of the cartridge fitting  404  provides for a space saving installation while providing for quick and easy change out of spent electrodes in an inline flow arrangement with the removable electrolytic cartridge  104 . 
     Although specific examples have been illustrated and described herein, it will be appreciated by those of ordinary skill in the art that any arrangement calculated to achieve the same purpose could be substituted for the specific examples shown. This application is intended to cover adaptations or variations of the present subject matter. Therefore, it is intended that the invention be defined by the attached claims and their legal equivalents.