Abstract:
A set of vertically stackable interacting cartridges for improving the delivery of biocide of a bulk feeder by positioning the stackable cartridges in a stacked condition within a chamber in the bulk feeder wherein the stackable cartridges are maintained in vertical interacting flow alignment with each other to provide enhanced control of the delivery of the biocide carried within each of the stackable cartridges without replacing the control valves of the bulk feeder.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims priority from U.S. provisional application Ser. No. 61/628,089 filed Oct. 24, 2011. 
     
    
     FIELD OF THE INVENTION 
       [0002]    This invention relates generally to dispensing cartridges and, more specifically, to an interactive stackable cartridge system for dispensing water purification materials from a feeder such as a bulk dispenser. 
       STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
       [0003]    None 
       REFERENCE TO A MICROFICHE APPENDIX 
       [0004]    None 
       BACKGROUND OF THE INVENTION 
       [0005]    One of the ways of ridding pools, spas or other bodies of water of harmful organism is to add a halogen such as chlorine or bromine to the body of water. Typically, the halogen may be added to the body of water through a bulk feeder. In the bulk feeder tablets or pucks of chlorine or bromine are placed in a chamber of the bulk feeder where the water flowing through the bulk feeder comes into contact with the halogen located therein. One of the disadvantages of the bulk feeders is that it is difficult to control the level of halogen that is dispersed into the body of water, which often results in over chlorination or over brominating of the body of water. While such bulk feeders are relatively inexpensive the cost of the overuse of chlorine and or bromine in the bulk feeders can quickly negate any benefits of the bulk feeder. To reduce the problem of over chlorination or bromination as well as improving the control of the level of chlorine or bromine in a body of water other types of feeders that separately dispense two different biocides may be used. 
         [0006]    One method and apparatus for controlling the harmful organisms in a body of water in a bulk feeder uses two dispensers that deliver two different biocides. Such a device is shown in King U.S. Pat. No. 7,347,935. In this device the two biocides are located in two separate dispensers that are placed in a free or non-fitted condition in the chamber of a bulk feeder. The dispensers are allowed to move about in the chamber in response to the fluid flow through the chamber of the feeder, which enables the water to come into contact with the biocides located therein. As the dispensers move about in the chamber of the feeder the biocides therein are released into the water passing through the chamber of the feeder. In such devices in addition to the control valve on the feeder the dispensers may include adjustable valves on each dispenser in order to better control the dispersant level of each of the biocides. 
         [0007]    Another chemical feeder for dispensing two chemicals into a pool is shown in U.S. Pat. No. 5,251,656 where two compartments containing water treatment materials with a venturi housing to draw the water treatment materials out of each of the compartments and into the pool. 
         [0008]    U.S. Pat. No. 6,471,858 shows a dispensing apparatus where a pair of cylindrical containers containing water treatment materials are located in a coaxial condition. The containers are cantileverly mounted within a top chamber in a sand filter, which allows the water to flow through both of the containers before flowing through a bed of sand. 
         [0009]    Another method and apparatus for accurately delivering two biocides from a single chamber in an inline feeder is shown in King U.S. Pat. Nos. 6,527,952 and 6,190,547. In this device two nestable canisters are concentrically positioned in the chamber of an inline feeder with each of the nestable canisters having inlets and outlets that separate the flow of water into two separate streams with each of the two streams following separate but parallel flow paths through the biocides in their respective nestable canisters. 
         [0010]    Since most feeders are integrally mounted in a circulation line of a body of water such as a pool or spa the conversion of a bulk feeder to a cartridge system that can accurately deliver two different biocides becomes costly since one may have to remove and replace the existing bulk feeder with a feeder that provides parallel flow paths through the dispensers therein . In other cases where the dispensers are free to move about the chamber of the feeder the task of control of the delivery rate of the biocides from the separate dispensers becomes more delicate since in addition to adjusting the setting of the control valve of the bulk feeder the valve of one or both of the dispensers may need to be adjusted to control the flow of water through the dispensers and hence the level of biocide that is delivered to the body of water. Thus a need exists for a cartridge system that can be used in prior art bulk feeders to alleviate problems of over halogenation but also provide a system for delivering two or more biocides to the body of water, which for example may be a pool, a spa or the like although the cartridge system may be used with any body of water which requires delivery of a biocide thereto. 
         [0011]    In contrast to the prior art the system described herein the invention allows one to provide dispersant control which avoids over halogenation of the body of water in existing bulk feeders and without having to separately adjust gate valves on each of dispensers used in the bulk feeder. 
       SUMMARY OF THE INVENTION 
       [0012]    A set of inline vertically stackable cartridges for improving the delivery of a biocide from a prior art bulk feeder using a set of stackable cartridges located in an end to end condition within a chamber in a bulk feeder wherein the stackable cartridges are maintained in flow alignment with each other to provide an interactive flow resistance that results in the feeder providing enhanced control of the delivery of each of the biocides carried therein without need to replace the control valve of the bulk feeder or to install a feeder with fitted cartridges. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]      FIG. 1  shows in cross section an example of a prior art bulk halogen feeder; 
           [0014]      FIG. 2  shows cross section an example of another type of prior art bulk halogen feeder; 
           [0015]      FIG. 2A  shows a swimming pool with a bulk feeder; 
           [0016]      FIG. 3  shows a top perspective view of a stackable cartridge; 
           [0017]      FIG. 4  shows a bottom perspective view of the stackable cartridge of  FIG. 3 ; 
           [0018]      FIG. 5  shows a bottom perspective view of another stackable cartridge; 
           [0019]      FIG. 6  shows a top perspective view of the stackable cartridge of  FIG. 5 ; 
           [0020]      FIG. 7  shows the prior bulk halogen feeder of  FIG. 1  containing the stackable cartridge of  FIG. 3  and  FIG. 5 ; 
           [0021]      FIG. 8  is a graph of the comparative control of a halogen in a bulk feeder with and without the cartridges therein; 
           [0022]      FIG. 9  is a cross section view of the bulk feeder of  FIG. 2  with a set of stackable cartridges located therein; 
           [0023]      FIG. 10  is a top view of a stackable cartridge; 
           [0024]      FIG. 11  is a front view of the stackable cartridge of  FIG. 10   
           [0025]      FIG. 12  is a bottom view of the stackable cartridge of  FIG. 10   
           [0026]      FIG. 13  is a top view of a second stackable cartridge; 
           [0027]      FIG. 14  is a front view of the stackable cartridge of  FIG. 13 ; 
           [0028]      FIG. 15  is a bottom view of the stackable cartridge of  FIG. 13 ; and 
           [0029]      FIG. 16  shows is a cross section view of the bulk feeder of  FIG. 2  with a set of three stackable cartridges located therein. 
       
    
    
     DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0030]      FIG. 1  shows a typical example of a prior art bulk halogen feeder  10 , which is sold by Hayward Industries, Inc., having a frusto conical housing  11  with a lower venturi  13  having an inlet  14  for directing a portion of the water flowing therethrough into a channel  15  and through a passage  16  and into chamber  20  where the water contacts the halogen  21 , which is in bulk form and is shown located below the water line  20   a  in the chamber  20 . In this example a rotateable control valve  17  allows one to increase or decrease the amount of water flowing into chamber  20  and consequently into contact with the bulk chlorine tablets  21  by reducing or increasing the spacing between valve end  17   a  and passage  16 . Once the water contacts the halogen tablets  21  the water can flow out of chamber  20  through a fluid passage  23   a  in a vertical stand tube  23  and back into the venturi  13  through the port  24 . A cover  27 , which is sealed to the housing  11  through an annular seal  28 , normally maintains the bulk feeder in a closed condition when the system is in use. It is this type of feeder that is prone to over halogenation because the water flows freely through the halogen tablets  21  before being discharged through the stand tube  23 . 
         [0031]      FIG. 2  shows another typical example of a prior art bulk halogen feeder  30 , which is sold by Rainbow Lifeguard Products, Inc., having a cylindrical housing  31  with a lower main line fitting  32  which attaches to an inline circulating system. A side tap  33   a  directs a portion of the water from the main line fitting  32  through a pipe  33  to a control valve  34 , which can be used to limit the flow of water from the main line through the chamber  35 . The housing includes a cover  36  and an annular seal  37 , which creates an airtight chamber  35 . In operation a portion the water flowing through the main line fitting  32  flows into side tap  33   a  through pipe  33 , control valve  34 , pipe  42  and inlet  42   a  where it can then flow through the bulk chlorine tablets  41 , which are located below the water line  35   a  in chamber  35 . The water with the dissolved halogen therein then flows out of the chamber  35  through outlet  43  and into the fitting  32  where it is returned to the main inline circulation system. This type of system has also been found to become over halogenated since the halogen tablets  41  are rapidly dissolved by the water flowing through the open chamber  35 . 
         [0032]    Briefly, in both of the above type of systems the halogen in puck or tablet form is located in the chamber of the bulk feeder while one attempts to control the release of the halogen therefrom by using a flow valve on the feeder to direct more or less water through the bulk halogen tablets, which are stacked loosely and randomly in the chamber of the bulk feeder. Unfortunately, the accurate and controlled delivery of halogen to the body of water becomes difficult when the tablets or pucks are located in the chamber in the bulk feeder since the delivery rate is sensitive to the variable resistance offered by the dissolvable halogen pucks or tablets as well as the number tablets or pucks that are located below the water line  35   a.  Because of the difficulty in accurately delivering the proper amount of halogen through bulk feeders such as described an operator may want to ensure that a minimum amount of halogen is always available in the water, which may result in valve settings on the feeder that causes over halogenation i.e. over chlorination or over bromination of the body of water. The above are two examples of bulk halogen feeders that are prone to over halogenation, however, other types of feeders may also be prone to problems of over halogenation. 
         [0033]    In order to better control the levels of halogen in existing bulk feeders the invention described herein includes a set of vertically stackable cartridges that can be placed in fluid alignment in the open chamber of the prior art bulk feeders to allow an operator to more accurately control the level of halogen delivered to a body of water even though only one of the vertically stackable cartridges may contain a halogen in puck or tablet form. As pointed out, one of the difficulties with bulk feeder systems that rely only on a halogen is that the level of halogen in the system must be maintained relatively high in order to ensure that the water is free of harmful organisms, which may result in the body. of water having an annoying or obnoxious chlorine or bromine smell if the water is over halogenated. 
         [0034]    One of the ways of lowering the level of the necessary halogen in a body of water is to use a two bactericide system that uses a secondary biocide material such as a source of metal ions in addition to the halogen which allows the halogen level to be maintained at a lower level since the two bactericides working together can effectively kill harmful microorganisms that would normally require a higher halogen level if only the halogen were present. The combination of the simultaneous delivery of two biocides can be effective in maintaining a system free of harmful organisms while at the same time reducing the obnoxious presence of high levels of halogens in the body of water. An example of a two-biocide or bactericide system is shown in my U.S. Pat. No. 6,527,952, which is herby incorporated by reference. Unfortunately, such two bactericide systems require the homeowner to replace the bulk halogen feeder with a new inline cartridge feeder in order to properly dispense and maintain the lower halogen level since the bulk feeder controls and the open chamber in the bulk feeders are generally not well suited for maintaining low levels of halogen in the body of water. 
         [0035]    The system described herein comprises a set of interacting vertically stackable cartridges that can be placed in a chamber of a bulk feeder, which normally holds halogen in bulk form, to provide a cartridge system that can more precisely deliver a halogen at a lower rate to the body of water, which allows one to maintain a lower halogen level in the body of water, while still maintaining the body of water in a safe condition with the system including the ability to adjust the valve on the bulk feeder to maintain the chlorine level at about 0.5 ppm or lower without modification of the bulk feeder. 
         [0036]      FIG. 3  shows a top perspective view of a vertically stackable cartridge  50  and  FIG. 4  shows a bottom perspective view of the stackable cartridge  50  for placement in a bulk feeder as part of an interacting stackable two cartridge system, which may be used to reduce over chlorination or over bromination in a bulk feeder that normally holds a halogen in solid form therein. Typically, lower stackable cartridge  50  contains a biocide, which may be minerals, for example, a source of metal ions such as silver ions or copper ions. The stackable cartridge  50  comprises a cylindrical container having a circular top member  51 , a bottom member  59  and a cylindrical side wall  52  which coact to form a chamber therein for holding and dispensing a biocide such as metal ions therefrom. The metal ions such as copper ions, silver ions, or zinc ions can be delivered from the chamber by minerals which are retained within the stackable cartridge during the dispensing process to provide a relatively fixed fluid resistance of flow through the stackable cartridge  50 . Bottom member  59  includes a feature comprising a diametrical extending valley  63  with a first set of fluid passages  63   a  on one side of valley  63  with the fluid passage  63   a  providing a first bottom fluid inlet to the chamber therein and a second set of fluid passages  63   b  on the opposite side of valley  63  with the fluid passages  63   b  providing a second bottom fluid inlet to the chamber in stackable cartridge  50 . 
         [0037]    The top member  51  includes a set of centrally positioned top fluid passages  53  for a restrictive flow of fluid therethrough. The top fluid passages  53  and the bottom fluid passages are sized so as to retain the solid biocides within the chamber of the stackable cartridge  50  while allowing water to flow into and out of the chamber in stackable cartridge  50 . Located around fluid passages  53  is a cartridge support or spacer comprising a set of three axial protrusions  54 ,  55  and  56 , which extend upward from inner top member  57 . The purpose of the support is to at least partially support a stackable cartridge there above as well as to provide a diametrical flow passage between the bottom of a top stackable cartridge  70  and the top of the bottom stackable cartridge  50 . The support can thus maintain the second or top stackable cartridge in a stacked but bottom spaced condition from the first stackable cartridge. In order to maintain the stackable cartridge  50  in proper operating position cartridge  50  includes a feature or locater  58  comprising a semi hemispherical vertical notch, which engages with a vertical feature of the bulk feeder such as a standpipe  23  ( FIG. 7 ) of the bulk feeder to maintain the cartridge in a fixed rotational position therein. In addition the bottom of cartridge  50  includes a further feature or locater  63  comprising a valley as well as cross-valley  61  and  62  which are also configured so as to interact with internal features on the bottom of bulk feeder to prevent rotation of the stackable cartridge  50  during the operation of the bulk feeder with the stackable cartridges located therein. While the locater or feature on the stackable cartridges is shown as notches or valleys in a side of stackable cartridge  50 , other types of locaters or features of the stackable cartridges may be used for engagement with features of the bulk feeder to maintain the stackable cartridges in the proper orientation so that water can be directed through the biocide in the stackable cartridge  50 . In this example the locator on the cartridge  50  and the locater  74  on the stackable cartridge  70  are in engagement with a common feature of the bulk feeder, namely, the standpipe  23  of the bulk feeder to maintain the stackable cartridge  50  and the stackable cartridge  70  in fluid alignment with each other to permit flow through the stacked cartridges  50  and  70 . Thus the vertically stackable cartridge system described herein can take advantage of internal features of the bulk feeder to maintain the stackable cartridges in a fixed rotational condition and in fluid alignment with each other in a bulk feeder, which can eliminate the condition of random flow of water through the halogen which is located in the chamber of the feeder. A further feature of the inline stackable cartridges is the use of biocide such as a non-dissolvable source of minerals in one of the stackable cartridges, which can also be used to both deliver a biocide and maintain an internal inline flow resistance during the delivery of the biocide to the body of water. A dissolvable biocide such as chlorine or bromine may be located in the other inline stackable cartridge. 
         [0038]      FIG. 5  shows a bottom perspective view of a stackable cartridge  70  and  FIG. 6  shows a top perspective view of the stackable cartridge  70  for stacking with the stackable cartridge  50  of  FIG. 3  and  FIG. 4 . The stackable cartridge  70 , which typically contains a halogen, comprises a cylindrical container having a circular bottom member  71  , a closed top member  73  and a cylindrical sidewall  72  which coact to form a chamber therein with an upper portion of chamber for trapping air therein and for holding a portion of a halogen such as chlorine or bromine in solid form above a water line therein to limit the water contact with the halogen and thus limit the dissolution rate of the halogen. The internal flow resistance of the flow path established between and within stackable cartridges allows the existing feeder control valve on the bulk feeder to be used to deliver a halogen at a more sustainable rate then if only halogen is located in the feeder. 
         [0039]    Extending in an axial direction along sidewall  72  is a feature or locater comprising an elongated hemispherical notch  74 . Notch  74  engages with a feature of the interior of the bulk feeder such as a standpipe  23  ( FIG. 7 ) to maintain the fixed rotational position of the stackable cartridge  70  with respect to the bulk feeder. Since the bottom portion of stackable cartridge  50  includes a similar locater  58  for engaging with the same standpipe the stackable cartridge  50  and stackable cartidge  70  can be maintained in the same orientation with respect to each other and to the bulk feeder to provide fluid alignment between the stackable cartridges as water flow into the bottom inlet of stackable cartridge  50  and out the outlet port  75  in top stackable cartridge  70 . 
         [0040]      FIG. 5  shows a bottom perspective view of stackable cartridge  70 , which may be used as a halogen stackable cartridge  70  revealing a fluid port having set of openings  29  with the fluid port centrally located in bottom member  73 . Port  29  permits ingress and egress of fluids therein while retaining a halogen in solid form therein. 
         [0041]      FIG. 7  shows a sectional view of a prior art bulk feeder  10 , which has been converted to a two biocide feeder, with the stackable cartridge  70  and the stackable cartridge  50  in section therein. The stackable cartridge  70  is stacked is a spaced condition on top of the cartridge  50  to form a diametrical fluid passage  81  therebetween. When the stackable cartridges  50  and  70  are located in a stacked condition the fluid inlet  29  in top member  70  is in axial fluid alignment with fluid outlet  53  in bottom member  5  lof the cartridge mineral dispenser  50 . In addition the cartridge  50  is positioned in the bottom of bulk feeder chamber  20  such that fluid from inlet  16  flows not only into the diametrical passage way  81  but also into the chamber  82  formed between the outside of stackable cartridge  50  and the inside wall  11   a  of housing  11  and the chamber located below cartridge  50 . Thus both parallel and series flow exists in this arrangement. 
         [0042]    To appreciate the flow of water through a bulk feeder  10 , which contains the stackable cartridge dispensers  50  and  70 , reference should be made to  FIG. 7 , which shows multiple sets of arrows to indicate the flow of water into and through the stacked dispensing cartridges  50  and  70 .  FIG. 7  shows that water from the main line venturi  13  enters the bulk feeder chamber  20  through the side inlet  16 . The flow of water then separates with some of the water flowing into and through a diametrical passage  81  located between the top of stackable cartridge  50  and the bottom of stackable cartridge  70  while some of the water flows into the bulk feeder lower chamber  82 , which contains the stackable cartridge  50 . In this example the stackable cartridge  50  contains a source of metal ions  85  such as a batch of minerals in granular form. The water in chamber  82  flows upward through the minerals  85  which are located in chamber  86  of stackable cartridge  50  thereby releasing metal ions into the water in chamber  86 . A portion of the water in chamber  82  flows axially upward through top outlet  53  of cartridge  50  and into chamber  87  through the bottom inlet  29  of halogen cartridge  70  where the water contacts a halogen such as solid chlorine pucks or tablets  91  thereby releasing chorine into the water. The water level in chamber  87  is indicated by water line  87   a  with a portion of the pucks or tablets  91  located below the water line. The water, which is chlorinated through the dissolution of the tablets or pucks therein, is then discharged though outlet  75  into an outlet passage  23   a  in stand pipe  23 . In addition to water flowing through the chlorine tablets  91  a portion of the water from diametrical passage  81  and chamber  82  can flow upward outside of cartridge  50  and cartridge  70  until it discharges through the standpipe  23 . The flow of water through the fluid resistance provided by stacked cartridges  50  and  70  and the contents therein results in the level of halogen to be maintained at lower levels using only the existing control valve  17  than if the tablets or pucks where placed in chamber  20  without the stackable cartridges therein. Thus the placement of the stacked cartridges  50  and  70 , which are located in a flow path as shown in  FIG. 7 , provides more accurate control of the level of halogen delivered by the bulk feeder than if the halogen tablets were located in the open chamber  20 . In addition, although the stackable cartridges contain no control valve the flow resistance of the stackable cartridges allows one to maintain a lower level of halogen using the existing control valve of the feeder since the stackable cartridges eliminates a direct flow path into and through the bulk halogen, which has been believed to be at least a partial cause of a problem of over halogenation with bulk halogen feeders. 
         [0043]    To illustrate the benefits obtained with the use of the stackable cartridges in comparison to a feeder without stackable cartridges reference should be made to  FIG. 8 .  FIG. 8  a graph of the chlorine output of a bulk feeder as a function of the bulk feeder control valve setting under bulk feeder conditions and the chlorine output of a bulk feeder as a function of the bulk feeder control valve setting when two interactive stackable cartridges are located in the chamber of the bulk feeder. Line  92  represents the chlorine output in ounces/per hour as a function of the position or setting of the control valve  17  in the bulk feeder mode i.e. using tablets or pucks of halogens in the bulk feeder as shown in  FIG. 1  . Located below line  92  is a dashed line representing a second chlorine output line  91 , which represents a desired maximum chlorine output rate and dashed line  90 , which represents a minimum chlorine output rate that should be maintained by the feeder in order to properly control the level of halogen so as to avoid conditions that would lead to under halogenation or under halogenation of the body of water when a halogen is used in conjunction with a second biocide such as a source of metal ions. As evident from the chlorine output  92  obtained with bulk feeder control valve, the use of the bulk feeder control valve  17  alone lacks the ability to reduce the chlorine delivery rates to delivery rates which would fall between line  91  and line  90 . 
         [0044]    Located between chlorine output line  91  and chlorine output line  90  is a third chlorine output line  93  which represents the actual chlorine output of the bulk feeder  10  obtainable with a set of interacting stackable cartridges  50  and  70  located in fluid series in the chamber of a bulk feeder. More specifically, the output  93  reflects bulk feeder  10  with a first stackable cartridge  50 , which contains a source of minerals such as a source of metal ions therein, and a second stackable cartridge  70 , which contains a biocide such as chlorine in bulk form with the flow of water directed through both stackable cartridges. As can be seen from  FIG. 8  the use of the two interacting stackable cartridges  50  and  70  provides more precise control of the chlorine output rate since the chlorine output rate is delivered at a much lower rate as a function of the control valve setting. Thus, using the same bulk feeder  10  with stackable cartridges  70  and  50  and the same settings of the bulk feeder control valve  17  one can obtain a much lower chlorine level output rate and a finer control of the chlorine output from a chamber  87  of the bulk feeder  10  as evidenced by the more gradual slope of line  93  as opposed to the slope of line  92 . Although, not fully understood the stackable cartridges  50  and  70 , which both contain static inlet and outlet openings, are believed to provide an interaction and flow resistance that allows one to lower the delivery rate of chlorine as well as provide better control of the delivery rate and consequently avoid conditions which may cause over chlorination even though the bulk feeder control valve  17  remains the same. In addition the stacked cartridge system allows one to maintain a lower level of halogen in the body of water which makes it suitable for a system that uses a second biocide. 
         [0045]      FIG. 9  shows an example of prior art bulk feeder  30  with a slightly different set of stackable cartridges  100  and  110  located in a stacked condition therein. The bulk feeder  30  is characterized by lacking internal features for maintaining the stackable cartridges  100  and  110  in fluid alignment with each other and with an inlet from the control valve  34 . 
         [0046]      FIGS. 10-12  show the bottom stackable cartridge  110  and  FIGS. 13-15  shows the top stackable cartridge  100 . Bottom stackable cartridge  110  comprises an annular housing  111  having a top member  112  with a central axial fluid passage  115  extending therethrough and a feature or locater comprising a top port  116  for engagement with a feature or locater of cartridge  100 . In the example shown the spout  104  on stackable cartridge  100  provides a flow path between a chamber  132  ( FIG. 9 ) in cartridge  110  and a chamber  131  ( FIG. 9 ) in cartridge  100  as well as a feature or locater for maintaining the fixed rotational alignment of cartridge  100  with respect to cartridge  110  and correspondingly the fluid alignment of cartridge  100  to cartridge  110 . 
         [0047]      FIG. 9  shows the lower annular housing  113  of stackable cartridge  110  engages a bottom member  31   a  on feeder housing  31  to support the cartridge  110  in an upright or vertical position on the bottom of the bulk feeder  30 , however, the lack of features which could lockingly engage the housing  30  precludes aligning an inlet of the cartridge  110  with the inlet  42   a  of the bulk feeder  30 . Instead cartridge  110  includes a bottom inlet comprising a set of circumferential spaced ports  119  with an annular support  114  for engagement with the bottom surface  31   b  of bulk feeder  30 . The set of ports  119  extend around a periphery of housing  113 , which as shown in  FIG. 9  are spaced from the interior wall  31   a  to form an annular chamber  133  so that the lower portion of housing  113  occupies less than an entire volume of the lower portion of the bulk feeder to enable water enter housing  31  to flow into annular chamber  133  before entering the peripheral bottom inlet port  119  in cartridge  110 . The annular chamber  133  allows the cartridge  110  to be placed in the bottom of bulk feeder  30  without the need for a locater or feature to maintain a fixed rotational position of the cartridge  110  with respect to the bulk feeder  30  since fluid can flow into the cartridge  110  from all sides of the cartridge through the peripherally spaced ports  119 . That is, the first stackable cartridge  110  includes a cylindrical surface setback  113  of a lower portion of the first cylindrical cartridge  110  from the top portion of the first stackable cartridge to create an annular fluid chamber  133  between a bulk feeder sidewall  31   a  and the cylindrical surface setback of the first stackable cartridge to permit flow in the chamber  133  around the lower portion of the first stackable feeder  110  before the water enters the bottom of stackable cartridge through the bottom peripheral ports  19 , which are spaced around the exterior of the stackable cartridge  110 . Correspondingly, the cylindrical spacing of the upper portion of first stackable cartridge  110  from the sidewall  31   a  of the bulk feeder  30  is dimensioned so as to be able to maintain the first stackable cartridge  110  in a stable upright position with clearance therebetween to allow the first stackable cartridge to be removed from the bulk feeder without the aid of tools when either or both of the stackable cartridges need to be replaced. 
         [0048]      FIGS. 13-15  show an example of an upper stackable cartridge  100 , which normally contains a halogen such as bulk chlorine or bulk bromine tablets therein, having a cylindrical side wall  102  with a closed top  101  and a bottom member  103  having a set of centrally located ports  105  and a locater  104  comprising a neck or spout having a fluid passage  104   a  therein. The purpose of locater  104  is to maintain the alignment of the outlet port  116  in stackable cartridge  110  with the inlet fluid passage  104   a  so that water that flows through minerals  134 , which are located in stackable cartridge  110  (see  FIG. 7 ) can be directed into the chamber  131  of stackable cartridge  100  to contact the halogen tablets  130  located therein. The set of openings or ports  105  in stackable cartridge  100  permit flow of water out of chamber  131  but are sufficiently small so as to prevent tablets or pucks of a halogen from falling therethrough. 
         [0049]      FIG. 9  shows the interacting of stackable cartridge  100  and stackable cartridge  110  when the cartridges are located in chamber  35  of prior art bulk feeder  30 . Both the stacked dispensing cartridges and the bulk feeder are shown in section to reveal the flow patterns through the stackable cartridges. The bulk halogen  130  , which normally is located in chamber  35  of the bulk feeder (see  FIG. 2 ), is now located in chamber  131  of stackable cartridge  100 . The source of metal ions, which was not found in the bulk feeder  30  is now located in annular chamber  132  in stackable cartridge  110 . 
         [0050]    In operation of the stackable cartridge  100  and stackable cartridge  110  the existing unmodified control valve  34  of bulk feeder  30  directs water through pipe  42   a  nd the inlet  42   a  and into an annular plenum chamber  133  in bulk feeder  30 . The water enters the bottom of cartridge  110  by flowing radially inward through the peripheral inlet openings  119  and into the minerals  134  therein. Thus, in cartridge  110  the water flows upward through the minerals  131  and out of chamber  132  through the top port  116  of stackable cartridge  110 . The water then enters cartridge  100  through inlet  104  and circulates upward through the bulk halogen tablets  130 , which are located in chamber  131  of stackable cartridge  100 . The water which then picks up the halogen from the halogen tablets therein flows out of chamber  131  though outlet ports  105 , which are located in axial alignment with the axial passage  115  in stackable cartridge  110 . The water, with the halogen therein, flows through the bulk feeder outlet  43  where it enters the main line. 
         [0051]    Thus, in the example shown in  FIG. 9  a stackable cartridge  110  containing a batch of minerals  134  includes a top member  112  and a bottom member  113  each having an opening ( 119 ,  116 ) for flow of a liquid therethrough while preventing passage of the minerals therethrough. The stackable cartridge container  100  containing a batch of halogen in solid form with a bottom member  103  having an inlet  104  for ingress of liquid therethrough while retaining the halogen in solid form therein and an outlet located below a top of the halogen cartridge  100  with the halogen cartridge  100  stackable on top of the mineral cartridge  110  to provide a flow path therebetween and an axial flow path from the halogen cartridge  100  through the mineral dispensing cartridge  110  wherby the liquid flows through the outlet  43 . Thus the lower stackable cartridge  110  supports the upper stackable cartridge  100  in a stacked condition where fluid can be directed vertically upward through a first chamber  132  in stackable cartridge  110  and into the chamber  131  in stackable cartridge  100  where after picking up the biocides from each of the chambers it starts it return journey to the main line from whence it came. 
         [0052]    In each of the above examples the flow of water through the stackable cartridges has been restricted by the materials in the stackable cartridges or by restricted features in the flow path between stackable cartridges. 
         [0053]    While the use of two stackable cartridges are shown and described in some cases there may be benefit and advantages to use of multiple stackable cartridges.  FIG. 16  shows the feeder of  FIG. 9  with three stackable cartridges located in the chamber of the feeder. In this example the top stackable cartridge  100  of  FIG. 9  has been replaced with two stackable cartridges  141  and  140 , although other configurations or sizes may be used which when stacked fit within the chamber of the feeder housing. 
         [0054]    In this example the water enters the first stackable cartridge  110  through port  42   a  of cartridge  110  and flows through minerals  134  and out the top of cartridge  110  and into stackable cartridge  141  through an inlet spout  147  which forms a feature that fits into the opening  116  in cartridge  110  to maintain the cartridge  110  and  141  in fluid alignment with each other. The water then enters the chamber  159  in stackable cartridge  141  where it contacts a water treatment material  143 . The water treatment material may be any of a number of different types of water treatment materials including an algaecide, a clarifier, a pH adjuster or other materials that are beneficial in maintaining the body of water in a safe condition for use by humans. One of the advantages of the use of a multiple stackable cartridge system is that different types of water treatment materials can be delivered continuously. This is particularly beneficial with a water treatment material such as a clarifier, which is consumed during the operation of the pool and must be periodically added to the pool. With the multiple stackable cartridges the clarifier can be added when the stackable cartridges are replaced to thereby provide release of a clarifier during an extended period of time. 
         [0055]    After flowing through the water treatment material  141  the water flows into spout  157  of stackable cartridge  140  which forms a feature that fits into outlet  149  of stackable cartridge  141  to hold the stackable cartridge  140  in fluid alignment with stackable cartridge  141  which is in turn held in fluid alignment with stackable cartridge  110 . Although spouts and mating openings are shown as features to maintain the stackable cartridges in fluid alignment other features and methods may be used. 
         [0056]    The water enters chamber  145  through spout  157  with the water filling the lower portion of chamber  145  as indicated by water line  145   a,  i.e., the interface between the water and the air that is trapped in the top of stackable cartridge  140  by the closed top  146  and the cylindrical sides of stackable cartridge  140 . The water flows through the chlorine tablets  130  and then out through a restrictive opening comprising a set of small openings  142  which prevent the tablets of pucks from falling through but allow the dissolved material to flow therethrough. The contact between the chlorine tablets and the water in chamber is limited since a portion of the chlorine tablets  130  are located above the water line  145   a.  This feature allows one to reduce the rate of dissolution of the chlorine tablets since a portion of the chlorine tablets are maintained in an out of the water and in an undissolved or uneroded condition during the initial phase of the chlorination. As the chlorine tablets  130  dissolve the tablets that are above the water line gradually fall below the water line and are dissolved or eroded and directed into the main line through outlet  142 . Thus the water which now contains materials from stackable cartridges  110 , 157  and  140  then flows down through passage  150 , passage  115  and opening  43  where it is returned to the main line. 
         [0057]    While the stackable cartridge containing the halogen has been shown as the top most stackable cartridge it may be located at a different vertical position. 
         [0058]    If it is desired to extend the halogen delivery of the halogen cartridge the use of a closed chamber with an air pocket to trap air therein allows one to extend the time before the water comes into contact with the halogen. However, in some cases one may wish to dispense with the air pocket as a means for extending the delivery of the halogen. 
         [0059]    In the event the halogen cartridge was not the last cartridge in a series of stacked cartridges the water would be directed in and out of the stackable cartridge with the halogen but instead of the water going directly to a return line the water would flow upward into another stackable cartridge or cartridges before returning to the main line. 
         [0060]      FIG. 2A  shows a swimming pool  38  using an existing bulk feeder  30 , which contains two or more cartridges connected to a pool circulation system comprising pipe  46 , pump  39  and pipe  42  with the output side of bulk feeder  30  connected to pool  38  through pipe  48 . In this example no system changes are needed to deliver two or more materials.