Abstract:
A medium having a support structure configured for circulation of a fluid therein, such as a replaceable filter cartridge, including a sanitizing agent which contains one or more reactants that are chemically configured for delivering chlorine dioxide or other sanitizing agents in a controlled dose to sanitize, deodorize, and disinfect upon being wetted by the fluid and positioned in the medium support structure to be exposed to the fluid circulating therein.

Description:
CROSS-REFERENCE TO RELATED APPLICATION(S)  
       [0001]    The subject application claims the benefit of priority to U.S. Provisional Patent Application No. 60/366,144, filed Mar. 20, 2002, the disclosure of which is herein incorporated by reference in its entirety. 
     
    
     
       BACKGROUND OF THE INVENTION  
         [0002]    1. Field of the Invention  
           [0003]    The subject invention relates to a system and method of water treatment, and more particularly, to systems and methods of delivering controlled doses of chlorine dioxide or other sanitizing agents into a pressurized water system. 2. Background of the Related Art  
           [0004]    Potable water contains various levels of background contaminants such as HPC, pathogenic bacteria and algae, even after municipal treatment. In most instances, chlorine is used to reduce the concentration of such background contaminants. Chlorine and chlorine compounds used for sanitization or disinfection are often removed from water supplies prior to use in drinking water systems, food service beverage systems and ice dispensing equipment. The reasons for removal vary depending on the application or system. For example, the presence of chlorine in the water supply to certain beverage systems may negatively impact a particular quality of the beverage product, such as its taste.  
           [0005]    There are also a significant amount of downstream potable water systems that do not use disinfection chemicals. This results in increased levels of microorganisms and biofilm build-up. The build-up increases within dechlorination filters, resin beds, and other finely divided media filters during periods of stagnation. The build-up can be released downstream at high levels causing health concerns, as well as severe off-tastes and odors. Over a prolonged period of time biofilm coats water lines and wetted parts of dispensing equipment, thus compounding the problem.  
           [0006]    The concern generated by known high levels of microorganism build-up has caused many in the food service and drinking water industry to periodically sanitize water lines, often reaching the threshold allowable by state or local regulations. Many of the sanitization procedures currently available are difficult to administer, costly, service intensive and use highly toxic chemicals. Some of the chemicals typically used in these procedures include peroxide, chlorine derivatives, muric acid and citric acid. Although the desired sanitizing effect may be achieved by these procedures, they are seldom implemented due to the aforementioned problems.  
           [0007]    Chlorine dioxide or other sanitizing agents have also been found to be highly effective as a sanitizer for use in potable water lines. Prior treatment procedures employed a highly concentrated solution of chlorine dioxide or other sanitizing agents, which is formed independently in a remote container and then pumped into the system lines. This solution is allowed to remain in the system lines for extended periods of time while the pressure in the water line is shut off.  
           [0008]    One of the primary disadvantages of using chlorine dioxide or other sanitizing agents as a sanitizer according to prior treatment procedures is the economic cost associated with the resulting system downtime since the system being sanitized is unusable during the treatment. Also, due to the toxic nature of the chlorine dioxide or other sanitizing agents solution, a specially trained service technician is often required to remain on-site until the solution is completely flushed out, thus further adding to the financial burden associated with these prior treatment procedures.  
           [0009]    The flushing process itself often significantly extends the system downtime of the prior treatment procedures because of a residue left in the system lines by the prolonged static exposure to the chlorine or other sanitizing agents solution. This residue is often difficult to remove, and even low levels of such residue may be considered toxic or noxious, thus requiring the repeated flushing of the system.  
           [0010]    It would be beneficial therefore, to provide a system and method for delivering controlled doses of chlorine dioxide or other sanitizing agents into a pressurized water system, which overcomes the deficiencies of the prior art.  
         SUMMARY OF THE INVENTION  
         [0011]    The present invention provides new and useful systems and methods for delivering controlled doses of chlorine dioxide or other sanitizing agents into a pressurized potable water system which overcomes the problems associated with the prior art.  
           [0012]    A medium having a support structure with an inlet configured for receiving a fluid, an outlet configured for delivering a fluid and a body configured for circulating a fluid therein, such as a replaceable filter cartridge, which includes a sanitizing agent containing one or more reactants that are chemically configured for releasing a compound having sanitizing properties, such as chlorine dioxide, in a controlled dose upon being wetted by the fluid and positioned within the medium to be exposed to the fluid circulating therein.  
           [0013]    Preferably, the sanitizing agent releases chlorine dioxide or other sanitizing agents in specific amounts, at a specific and controlled constant rate, to sanitize, deodorize, and disinfect equipment pipes connected to the medium outlet. The rate of chlorine dioxide or other sanitizing agents release would be set to dilute in water with a constant flow rate for a duration equivalent to perform the desired task, such as sanitize, deodorize, or disinfect water lines and equipment wetted parts.  
           [0014]    The preferred mediums to be used in accordance with the present invention include systems or disposable cartridges. In particular, the present invention, is directed to a system for delivering a sanitizing agent to a fluid, which includes a substantially hollow vessel and a sanitizing agent having one or more reactants which are chemically configured to release a compound having sanitizing properties upon exposure to the fluid. The hollow vessel includes an inlet passage configured for receiving fluid flow, an outlet passage configured for fluid egress, and an interior chamber configured for receiving fluid from the inlet passage and providing temporary confinement of the fluid therein prior to egress from the outlet passage. The sanitizing agent is disposed in the chamber and the confinement of water therein may be provided by an independent valve.  
           [0015]    The present invention is also directed to a filter cartridge that includes a hollow housing with a filter media chamber defined therein and a sanitizing agent disposed in the filter media chamber. The sanitizing agent preferably includes one or more reactants which are chemically configured to release a compound having sanitizing properties upon exposure to the fluid in the filter media chamber.  
           [0016]    There can be inlet passage in the housing configured to provide fluid communication with the chamber and an outlet passage in the housing configured to provide fluid communication with the chamber. The fluid is directed to the inlet passage and flows through the filter media chamber, exiting the outlet passage with chlorine dioxide or other sanitizing agents from a portion of fluid included therewith having been exposed to the sanitizing agent in the filter media chamber.  
           [0017]    Preferably, the fluid is water and the compound is chlorine dioxide or other sanitizing agents, in which case, the one or more reactants can include a chlorite and the release of chlorine dioxide or other sanitizing agents is initiated by contact with the water. The chlorite may be an aqueous soluble chlorite selected from the group consisting of sodium chlorite and potassium chlorite and mixtures thereof. Preferably, the one or more reactants include an aqueous soluble chlorite and an aqueous soluble acid. Preferably, the aqueous soluble acid is selected from the group consisting of phosphoric acid, fumaric acid, glycolic acid, acetic acid, ascorbic acid, oxalic acid, maleic acid, lactic acid, tartaric acid, citric acid and mixtures thereof.  
           [0018]    In addition, the system or filter cartridge of the present invention may also include a filtration media disposed in the chamber along with the sanitizing agent. The filtration media may be configured to provide chemical or mechanical filtration depending on the application. Preferably, the filtration media and sanitizing agent are disposed in the chamber and configured so that fluid entering the chamber is first exposed to the filtration media prior to being exposed to the sanitizing agent and exiting the outlet.  
           [0019]    In another embodiment which can be implemented in any medium (e.g., cartridge or system) constructed in accordance with the present invention, a solution may be disposed in the chamber that includes a second compound having sanitizing properties, such as chlorine. This solution is then mixed with fluid flowing in the chamber and exits through the outlet passage.  
           [0020]    In yet another embodiment which can be implemented in any medium constructed in accordance with the present invention, a substantially hollow neck is mated with the chamber. The neck has an inlet port in fluid communication with an inlet passage that is configured to be in fluid communication with the chamber, and an outlet port in fluid communication with an outlet passage that is also configured to be in fluid communication with the chamber. The inlet passage and outlet passage are both disposed in the neck and configured to provide dual fluid flow within the neck and independent fluid communication with the chamber.  
           [0021]    The aforementioned embodiment may further include a tubular member disposed axially in the neck and having a portion with a porous periphery extending into the chamber. The tubular member defines an inner axial passage therein and a radially outer axial passage bounded by the periphery of the tubular member and inner surface of the neck. Thus, the outer axial passage and the inner axial passage can provide the inlet and outlet passages, respectively. A filtration media may be disposed along the porous periphery of the portion of the tubular member extending into the filter media chamber and the sanitizing agent can be disposed within the inner axial passage of the portion of the tubular member extending into the chamber. Preferably, the sanitizing agent is separated from the filtration media by an inert porous divider.  
           [0022]    In yet another embodiment which can be implemented in any medium constructed in accordance with the present invention, a second outlet port may be added to the housing or vessel at a position where it will be in fluid communication with the chamber, and adjacent relative to the position of the sanitizing agent within the chamber, so that a majority or substantially all of the fluid exposed to the sanitizing agent exits this second outlet.  
           [0023]    Further features of the subject invention will become more apparent from the detailed description of the present invention that follows taken in conjunction with the drawings. 
       
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0024]    So that those having ordinary skill in the art to which the present application appertains will more readily understand how to make and use the same, reference may be had to the drawings wherein:  
         [0025]    [0025]FIG. 1 is a representative illustration of a system for providing controlled dosing of chlorine dioxide or other sanitizing agents to sanitize and clean equipment pipes or lines constructed in accordance with a preferred embodiment of the present invention, which depicts the system including a dry sanitizing agent, which releases chlorine dioxide or other sanitizing agents upon wetting with water, and a liquid sanitizing agent and a filter head for connecting the system with the equipment;  
         [0026]    [0026]FIG. 2 is a representative illustration of a filter cartridge for providing controlled dosing of chlorine dioxide or other sanitizing agents to sanitize and clean equipment pipes or lines constructed in accordance with a preferred embodiment of the present invention, including a dry sanitizing agent, which releases chlorine dioxide or other sanitizing agents upon wetting with water, a filtration media, a first outlet for water exposed to the filtration media, and a second outlet for providing water exposed to the sanitizing agent; and  
         [0027]    [0027]FIG. 3 is a representative illustration of a filter cartridge for providing controlled dosing of chlorine dioxide or other sanitizing agents to sanitize and clean equipment pipes or lines constructed in accordance with a preferred embodiment of the present invention, including a dry sanitizing agent, which releases chlorine dioxide or other sanitizing agents upon wetting with water and a filtration media, wherein the outlet stream from the filter cartridge contains a blend of water exposed to the filtration media and water exposed to the sanitizing agent. 
     
    
       [0028]    These and other features of the subject invention will become more readily apparent to those having ordinary skill in the art from the following description of the preferred embodiment.  
       DETAILED DESCRIPTION OF THE INVENTION  
       [0029]    In the following detailed description of the present invention, references are made to the accompanying drawings, which form a part hereof, and in which is shown by way of illustration specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention, and it is to be understood that other embodiments may be utilized and that structural changes may be made without departing from the spirit and scope of the present invention. The following detailed description is, therefore, not to be taken in a limiting sense, and the scope of the present invention is defined by the appended claims and equivalents thereof.  
         [0030]    The present invention provides vehicles, such as replaceable filter cartridges, for delivering chlorine dioxide or other sanitizing agents to a water system in a variety of controlled doses periodically by exposure of the water in the system to sanitizing or cleaning agents. These agents may include stable dry chemicals such as, but not limited to, those which are disclosed in the herein incorporated Published International Patent Application WO 01/60750A3 (PCT/US01/05002), capable of generating chlorine dioxide or other sanitizing agents when wetted. Preferably, the agent or agents release a specific amount of chlorine dioxide or other sanitizing agents, at a specific and controlled constant rate. The rate of chlorine dioxide or other sanitizing agents release would be set to dilute in water with a constant flow rate for a duration equivalent to clean (sanitize) water lines and equipment wetted parts.  
         [0031]    Referring now to the drawings wherein like reference numerals identify similar structural features of the invention, there is illustrated in FIG. 1, a representative depiction of a stand-alone type system for providing controlled dosing of sanitizer/cleaner into pressurized water systems which is constructed in accordance with a preferred embodiment of the subject invention and designated generally by reference numeral  10 .  
         [0032]    System  10  includes a pressure vessel  12  having a first end  14  and a second end  16  defining a hollowed out, generally cylindrical chamber  18  therein. First end  14  has a neck  20  which has an inlet port  22  in fluid communication with an inlet passage for directing fluid flow into chamber  18  according to arrow  24  (hereinafter referred to as “inlet passage  24 ”). Neck  20  also includes an outlet port  26  in fluid communication with an outlet tube  28  which extends axially into chamber  18 . In this embodiment, neck  20  also includes an optional bypass passage which provides fluid communication between inlet passage  24  and outlet port  26  in accordance with arrow  30  (hereinafter referred to as “bypass passage  30 ”).  
         [0033]    Chamber  18  includes an unfilled region  32  adjacent first end  14 , a first treatment region  34  containing a dry sanitizing agent  36  with controlled reaction dissolution and a second treatment region  38  containing a concentrated sanitizing liquid  40  adjacent second end  16 . First treatment region  34  and second treatment region  38  are separated from each other by a porous inert divider  42 . Sanitizing liquid  40  is preferably chlorine and may also include a dye indicator for facilitating awareness of its exhaustion.  
         [0034]    System  10  is attachable to the water supply line (not shown) to a master system (not shown), such as a beverage preparation device or ice making machine, via a filter head  44  having a first line  46  for receiving fluid from a supply line (not shown), a second line  48  for providing fluid to the master system and a treatment device port  50 . Filter head  44  may be constructed with or retrofitted onto the supply line or any other lines in the master system. System  10  may also be connected to the master system in other ways, such as by a permanent connection having flow control valves. Treatment device port  50  separates first line  46  and second line  48  and to provide a space in which neck  20  of system  10  may be inserted. Filter head  44  may also include a line pressure bypass with constant flow rate. The flow rate may vary depending on the application but typically ranges from about 0.25 gallons per minute to about 5.0 gallons per minute.  
         [0035]    Preferably, the outer periphery of neck  20  and the inner surface of treatment device port  50  are configured to be engaged by corresponding cooperative structures defined respectively thereon. The cooperative structures may consist of a proprietary interconnection Also, it is preferable that neck  20  and treatment device port  50  be sealingly engaged (e.g., using water resistant sealing rings fabricated of an elastomeric material) to maintain the integrity of fluid communication between the first line  46  and inlet port  22 , and between outlet port  26  and second line  48 , respectively.  
         [0036]    Once system  10  is installed in filter head  44  (i.e., neck  20  is engaged with treatment device port  50 ), water is provided to first line  46  and allowed to enter inlet port  22 . A portion of the water flow entering inlet port  22  will travel through inlet passage  24  into chamber  18  while the remaining portion of water flow will travel through bypass passage  30 . Bypass passage  30  is configured to direct the water flowing therein through outlet port  26  sans treatment, to be diluted with the treated water also exiting from outlet port  26 .  
         [0037]    The water flowing through inlet passage  24  pours into unfilled region  32  of chamber  18  creating turbulence as indicated by arrows  52  which facilitates better mixing of the untreated water and greater contact with the sanitizers in treatment regions  34  and  38  within chamber  18 .  
         [0038]    The pressure of the incoming flow forces water within unfilled region  32  through first treatment region  34 , porous divider  42 , and second treatment region  38  before exiting chamber  18  via outlet tube  28 . As the water passes through treatment regions  34  and  38 , it is exposed to dry sanitizing agent  36  and concentrated sanitizing liquid  40 . The flow from outlet tube  28  mixes with untreated water flowing from outlet  26  via bypass passage  30  (if included) before being directed to the master system via second line  48  in filter head  44 . Preferably, for this embodiment, the water flowing to the master system contains about 0.1 parts per million of sanitizer to about 10 parts per million of sanitizer after passage through system  10 .  
         [0039]    Another preferred embodiment of the present invention is represented by the depiction in FIG. 2 of a filter cartridge having a separate sanitizer stream for providing controlled dosing of sanitizer/cleaner into pressurized water systems, which is constructed in accordance with the subject invention and designated generally by reference numeral  110 .  
         [0040]    System  110  includes a filter cartridge housing  112  having a first end  114  and a second end  116  defining a hollowed out, generally cylindrical chamber  118  therein. First end  114  has a neck  120  which has an inlet port  122  in fluid communication with an inlet passage for directing fluid flow into chamber  118  according to arrow  124  (hereinafter referred to as “inlet passage  124 ”). Neck  120  also includes an outlet port  126  in fluid communication with an outlet tube  128  extending axially into chamber  118 . In this embodiment, filter cartridge housing  112  also includes a separate sanitizer line  154  that draws fluid from chamber  118  adjacent to second end  116  of filter cartridge housing  112 .  
         [0041]    Chamber  118  includes an axially disposed, radially porous center core  156  and radially outer first treatment region  134  containing a filtration media  158  adjacent first end  114 , which may be mechanical or chemical in nature (e.g., a peat block, screen, activated carbon block, sediment block, granular media, etc.), and which substantially surrounds center core  156 . Center core  156  includes a first open axial end  160  adjacent to first end  114  of filter cartridge housing  112  and a second open axial end  162  adjacent to second end  116  of filter cartridge housing  112 .  
         [0042]    The second open end  162  of center core  156  is adjacent to a second treatment region  138  containing a dry sanitizing agent  136  with controlled reaction dissolution. First treatment region  134  and second treatment region  138  are separated by a porous inert divider  142 . In addition, filtration media  158  is configured and dimensioned to fit within filter cartridge housing  112  to define an unfilled annular region  132  between the inner circumferential surface of chamber  118  and the outer periphery of filtration media  158  for fluid flow therebetween, as illustrated by arrows  164 .  
         [0043]    Filter cartridge  110  is attachable to a supply line (not shown), preferably located within the housing of a master system (not shown), such as a beverage preparation device or ice making machine. This may be accomplished via a filter head (not shown) as in the previous embodiment or other connection having a port configured to engage neck  120 .  
         [0044]    When system  110  is in use, water pumped through the supply line enters inlet port  122  and flows into chamber  118  through inlet passage  124  in neck  120  of filter cartridge housing  112 . As illustrated by arrows  164 , the water flows through the unfilled annular region  132  and is pushed radially inward by the fluid pressure created in cartridge housing  112 . The water is forced through filtration media  158  and into center core  156 . A portion of the water flow in center core  156  is directed towards first end  114  and into outlet tube  128 , eventually exiting filter cartridge housing  112  through outlet port  126 , as illustrated by arrows  166 . Preferably, the majority of the water flow follows the path shown by arrows  166 .  
         [0045]    A portion of the water entering unfilled annular region  132  flows axially toward second end  116  in chamber  118  and into second treatment region  138  through porous inert divider  142  without passing through filtration media  158 , as illustrated by arrow  168 . A portion of the water flow in center core  156  which has passed through filtration media  158  is directed by pressure, or lack thereof, toward second end  116 . This flow of treated water exits center core  156  from second open end  162  and enters into second treatment region  138  through porous inert divider  142 , as illustrated by arrow  170 . Water flowing within second treatment region  138  contacts dry sanitizing agent  136  and then exits filter cartridge housing  112  through separate sanitizer line  154 . The water exposed to dry sanitizing agent  136  may be controlled by a control valve  172  in sanitizer line  154 .  
         [0046]    Another preferred embodiment of the present invention is represented by the depiction in FIG. 3 of a filter cartridge having an encapsulated sanitizing agent for providing controlled dosing of sanitizer/cleaner into pressurized water systems, which is constructed in accordance with the subject invention and designated generally by reference numeral  210 .  
         [0047]    System  210  includes a filter cartridge housing  212  having a first end  214  and a second end  216  defining a hollowed out, generally cylindrical chamber  218  therein. First end  214  has a neck  220  which has an inlet port  222  in fluid communication with an inlet passage for directing fluid flow into chamber  218  according to arrow  224  (hereinafter referred to as “inlet passage  224 ”). Neck  220  also includes an outlet port  226  in fluid communication with an outlet tube  228  extending axially into chamber  218 .  
         [0048]    Chamber  218  includes an axially disposed, radially porous center core  256  and radially outer first treatment region  234  containing a filtration media  258  that extends axially substantially from first end  214  to second end  216  and substantially surrounds center core  256 . Filtration media  258  is configured and dimensioned to provide an unfilled annular region  232  between the inner circumferential surface of chamber  218  and the outer periphery of filtration media  258  for fluid flow therebetween, as illustrated by arrows  264 . Filtration media  258  may be mechanical or chemical in nature (e.g., a peat block, screen, activated carbon block, sediment block, granular media, etc.).  
         [0049]    Center core  256  includes an open axial end  260  adjacent to first end  214  of filter cartridge housing  212  and a second treatment region  238  containing a dry sanitizing agent  236  with controlled reaction dissolution adjacent to second end  216  of filter cartridge housing  212 . An axially disposed porous inert divider  242  separates second treatment region  238  from the remaining portion of center core  256 .  
         [0050]    Filter cartridge  210  is attachable to a supply line (not shown), preferably located within the housing of a master system (not shown), such as a beverage preparation device or ice making machine. This may be accomplished via a filter head (not shown) as in the previous embodiments or other connection having a port configured to engage neck  220 .  
         [0051]    In use, water is pumped through supply line and flows from inlet port  222  to chamber  218  through inlet passage  224  in neck  220  of filter cartridge housing  212 . As illustrated by arrows  264 , the water flows through the unfilled annular region  232  and is pushed radially inward by fluid pressure. Water is forced through filtration media  258  and into center core  256 , where it makes its way into outlet tube  228  and exits cartridge housing  212  through outlet port  226 , as illustrated by arrows  266 .  
         [0052]    A portion of the water flow forced through filtration media  258  also enters second treatment region  238  and contacts dry sanitizing agent  236 , as illustrated by arrow  268 . The water exposed to dry sanitizing agent  236  flows through porous inert divider  242 , as shown by arrows  270 , where it mixes with water which has not been treated by dry sanitizing agent  236  before exiting filter cartridge housing  212 , as described above.  
         [0053]    Preferably, predetermined amounts of dry sanitizing agent  236  is encapsulated in a sanitary cartridge such as cartridge  110  and  210 , in a way, that would allow the full flow of fluid therethrough. A suitable encapsulated sanitary cartridge configuration is manufactured by Cuno Incorporated of Meriden, Conn., and sold under the tradename SQC® series drinking water system.  
         [0054]    System  10  and cartridges  110  and  210 , or other similar devices constructed in accordance with the present invention, may have a variety of end connector configurations to fit existing filter systems for periodic insertion and activation, as well as proprietary interconnects. A system or cartridge constructed in accordance with the present invention can also be incorporated into master system downstream of any absorbent media and can be removed or left in place until replaced for another treatment depending upon the filter head configuration. Furthermore, a system or cartridge of the present invention can be a standard component, which would be either supplied as part of a new installation, as a retrofit or as a replacement medium for chlorine dioxide or other sanitizing agents dosing.  
         [0055]    Various doses of chlorine dioxide or other sanitizing agents may be administered via the systems and cartridges of the present invention. For example, the periodic high dosing of chlorine dioxide or other sanitizing agents may be accomplished by utilizing predetermined amounts of a sanitizing agent that also allows full flow through the cartridge. Once installed, water can be introduced into a system or cartridge of the present invention is filled with the outlet port restricted. Once wetted the agent would generate chlorine dioxide or other sanitizing agents within the cartridge for a predetermined period of time, until a high level (e.g., 50 parts per million to 100 parts per million) is dissolved into the water in the system or cartridge chamber. The outlet port may be opened when ready and the chlorine dioxide or other sanitizing agents rich water can be forced by water pressure downstream into the water lines and equipment wetted parts, thereby stripping biofilm therefrom.  
         [0056]    The concentrated solution may be allowed to reach all exit ports of the downstream equipment. Thereafter, the outlet line of the master system can be shut off. The chlorine dioxide or other sanitizing agents rich solution may be held for a predetermined amount of time (e.g., from twenty minutes to several hours) to facilitate the stripping of biofilm buildup in the master system lines and sanitize the water and wetted equipment parts. The master system can then be flushed for a prescribed amount of time so as to clear the water lines and cartridge of any remaining chlorine dioxide or other sanitizing agents residue. One of the advantages of using chlorine dioxide or other sanitizing agents is its powerful oxidation capabilities and the ease by which residue is flushed out of the system.  
         [0057]    For high dosing as described above, the rate of chlorine dioxide or other sanitizing agents generation is rapid, but its release from the cartridge or stand alone system can be set to dilute in water with a constant flow rate, preferably between 50 parts per million and 100 parts per million, for a duration equivalent to fill water lines and equipment wetted parts.  
         [0058]    Low doses of chlorine dioxide or other sanitizing agents (i.e., about 0.1 parts per million to about 0.5 parts per million) can also be delivered into the water system periodically by exposure of the water in the system to sanitizing or cleaning agents contained in a system or cartridge constructed in accordance with the present invention. For example, a low-level chlorine dioxide or other sanitizing agents dosing agent may be incorporated into a cartridge, such as cartridge  210 , which are constructed in accordance with the present invention, along with other reduction, removal or absorptive capabilities, or combinations thereof. Upon installation, the agent can generate chlorine dioxide or other sanitizing agents at a low controlled rate for a short duration. Preferably, the chlorine dioxide or other sanitizing agents generation occurs at a location that is downstream of any absorbent media within the same cartridge. As water enters the filter cartridge, chlorine dioxide or other sanitizing agents generation begins. The absorbent and reduction media would perform as normal for their prescribed life (e.g., 3 months, 6 months or 1 year), while the chlorine dioxide or other sanitizing agents generation would end within the first few minutes of use (e.g., from about 5 to about 20 minutes). The net result would be the periodic sanitization of water lines and equipment wetted parts with the convenience of a standard cartridge replacement.  
         [0059]    In addition, a system or cartridge constructed in accordance with the present invention provides for the safe transportation and handling of chlorine dioxide or other sanitizing agents producing agents, controlled low level dosing rate in a dynamic flowing condition, controlled dosing duration, and system or cartridge formats and head assemblies which can introduce chlorine dioxide or other sanitizing agents into a pressurized water line.  
         [0060]    While the present invention has been described with respect to preferred embodiments, those skilled in the art will readily appreciate that various changes and/or modifications can be made to the present invention with departing from the spirit or scope of the invention. For example, a filter cartridge may be constructed having a sanitizing agent in accordance with the present invention and with a bypass feature such as, but not limited to, those filter cartridges which are disclosed in the herein incorporated, copending and commonly owned U.S. patent application Ser. No. 10/337,832 filed on Jan. 7, 2003.