Abstract:
The subject matter of this specification can be embodied in, among other things, a filter replacement kit that includes a filter cartridge. The filter cartridge includes a filter body, a filter media disposed within the filter body, a neck portion having a fluid inlet and a fluid outlet, and a cartridge engagement mechanism on the neck portion for engaging a manifold assembly. The cartridge engagement mechanism includes at least one filter engagement surface. The filter replacement kit also includes compatibility indicia indicating that the filter cartridge is compatible with at least one appliance. The at least one appliance includes the manifold assembly including a manifold engagement mechanism having a manifold engagement surface with first and second horizontal portions, and an angled portion disposed between and joining the first horizontal portion to the second horizontal portion, wherein the filter engagement surface is non-congruent to the manifold engagement surface.

Description:
CROSS REFERENCE TO RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. Provisional Application Ser. No. 62/076,409, filed Nov. 6, 2014, the content of which is incorporated herein by reference in its entirety. 
     
    
     TECHNICAL FIELD 
       [0002]    This instant specification relates to filter assemblies. 
       BACKGROUND 
       [0003]    The present disclosure relates generally to the field of residential and commercial filtration products, such as water filtration products. The filter assemblies can be used to filter any one of a range of fluids, such as water, oil, biological preparations, beer, wine, other beverages, other consumable liquids and the like. For convenience, the discussion below focuses on water filtration, although the filter assemblies can generally be used for other applications based on the disclosure herein. 
         [0004]    Water filter assemblies, such as point-of-use water filtration systems have become increasingly common in the residential and commercial environment. There are many advantages to these types of systems in addition to the improvements to taste and appearance of the water. In situations where the source water has been municipally treated, point-of-use systems allow the water to retain the disinfecting properties imparted by the municipality until the moment of use such that chances of undesirable microbial contamination is correspondingly reduced. These point-of-use filtration systems can also be individually tailored to treat specific properties of the source water. 
         [0005]    One disadvantage of point-of-use filtration systems in the residential and commercial environment is that they must be designed to fit in the limited spaces available to house the systems in these markets. As the design must be compact and unobtrusive, these systems must be designed to allow for frequent and easy replacement of used and exhausted filter elements. Because many of the users in the commercial and residential market may be unfamiliar with the potential dangers of working with a pressurized system, the filtration systems must also be designed with the safety of the user in mind. 
         [0006]    To that end, during normal operation of the filters utilized in the point-of-use water filtration systems, the potential for self uncoupling, i.e., disconnection without user intervention, of the filter cartridge from the filter manifold should be eliminated to prevent unwanted leakage and subsequent disengagement of the filter assembly while also permitting the assembly to disconnect safely should an increased pressure condition occur beyond the structural failure point of the filter assembly. Further, the act of uncoupling the filter cartridge utilized in the point-of-use water filtration systems from the filter manifold utilized in the system should also permit the relief of any excess pressure in a controlled manner to reduce the risk of damage or personal injury to the point-of-use water filtration system user. 
       SUMMARY 
       [0007]    In general, this document describes replacement filter assemblies. 
         [0008]    In a first aspect, a filter replacement kit includes a filter cartridge. The filter cartridge includes a filter body, a filter media disposed within the filter body, a neck portion having a fluid inlet and a fluid outlet, and a cartridge engagement mechanism on the neck portion for engaging a manifold assembly, the cartridge engagement mechanism including at least one filter engagement surface. The filter replacement kit also includes compatibility indicia, wherein the compatibility indicia indicates that the filter cartridge is compatible with at least one appliance. The at least one appliance includes the manifold assembly including a manifold engagement mechanism having a manifold engagement surface with a first horizontal portion, a second horizontal portion, and an angled portion disposed between and joining the first horizontal portion to the second horizontal portion, and wherein the filter engagement surface is non-congruent to the manifold engagement surface. 
         [0009]    Various embodiments can include some, all, or none of the following features. The filter engagement surface may not include a first filter horizontal portion, a second filter horizontal portion and an angled filter portion disposed between and joining the first filter horizontal portion to the second filter horizontal portion. The at least one filter engagement surface can include first and second filter engagement surfaces on generally opposite sides of the neck portion, wherein the first filter engagement surface may include no more than one horizontal portion. The at least one filter engagement surface can include first and second filter engagement surfaces on generally opposite sides of the neck portion, wherein the first filter engagement surface may include no more than one horizontal portion and an angled portion. The filter engagement surface can include an arcuate portion. The filter engagement surface can include two separated arcuate surfaces extending from an outer surface of the neck portion and disposed within 180 degrees of rotation on the outer surface, wherein the two arcuate surfaces may be spaced axially and circumferentially apart from each other with respect to a centerline axis of the filter cartridge extending in a longitudinal direction. The filter engagement surface can include two posts. The filter engagement surface can include two arcs. The filter engagement surface can include two separated tabs on an outer surface of the neck portion disposed within 180 degrees of rotation on the outer surface and the two separated tabs can be spaced axially and circumferentially apart from each other with respect to a centerline axis of the filter cartridge extending in a longitudinal direction. The at least one appliance can be a refrigerator manufactured by Electrolux, GE, Haier, or Bosch with the manifold assembly. 
         [0010]    In a second aspect, a filter replacement kit includes a replacement filter cartridge. The replacement filter cartridge includes a filter body, a filter media disposed within the filter body, a neck portion having a fluid inlet and a fluid outlet, and a cartridge engagement mechanism on the neck portion for engaging a manifold assembly, the cartridge engagement mechanism comprising at least one filter engagement surface, and compatibility indicia, wherein the compatibility indicia indicates that the replacement filter cartridge is a compatible replacement for at least one replaceable filter cartridge. The at least one replaceable filter cartridge includes a replaceable filter engagement mechanism having a replaceable filter engagement surface with a first horizontal portion, a second horizontal portion, and an angled portion disposed between and joining the first horizontal portion to the second horizontal portion, and the filter engagement surface is non-congruent to the replaceable filter engagement surface. 
         [0011]    Various embodiments can include some, all, or none of the following features. The filter engagement surface may not include a first filter horizontal portion, a second filter horizontal portion and an angled filter portion disposed between and joining the first filter horizontal portion to the second filter horizontal portion. The at least one filter engagement surface can include first and second filter engagement surfaces on generally opposite sides of the neck portion, wherein the first filter engagement surface may include no more than one horizontal portion. The at least one filter engagement surface can include first and second filter engagement surfaces on generally opposite sides of the neck portion, wherein the first filter engagement surface can include no more than one horizontal portion and an angled portion. The filter engagement surface can include an arcuate portion. The filter engagement surface can include two separated arcuate surfaces extending from an outer surface of the neck portion and disposed within 180 degrees of rotation on the outer surface, wherein the two arcuate surfaces may be spaced axially and circumferentially apart from each other with respect to a centerline axis of the filter cartridge extending in a longitudinal direction. The filter engagement surface can include two posts. The filter engagement surface can include two arcs. The filter engagement surface can include two separated tabs on an outer surface of the neck portion disposed within 180 degrees of rotation on the outer surface and the two separated tabs can be spaced axially and circumferentially apart from each other with respect to a centerline axis of the filter cartridge extending in a longitudinal direction. The at least one replaceable filter cartridge can be a replaceable filter cartridge having a model identifier selected from the group consisting of EPTWFU01, EWF02, MSWF, 60218743, 9000 674655, 4US-MAXL-F01 &amp; 4US-MAXS-F01, 4US-RO-POST, 4US-RO-POSTH, 4WH-QCTO-F01, 4WH-QS-F01, and 4WH-QSS-F01H. 
         [0012]    In a third aspect, a method of replacing a filter cartridge includes removing a replaceable filter cartridge from a manifold assembly, wherein the manifold assembly comprising a manifold engagement mechanism having a manifold engagement surface with a first horizontal portion, a second horizontal portion, and an angled portion disposed between and joining the first horizontal portion to the second horizontal portion, inserting a replacement filter cartridge into the manifold assembly, wherein the replacement filter cartridge comprises a replacement cartridge engagement mechanism comprising a replacement cartridge engagement surface that is non-congruent to the manifold engagement surface and turning the replacement filter cartridge to engage the filter engagement surface with the manifold engagement surface. 
         [0013]    Various implementations can include some, all, or none of the following features. The replaceable filter cartridge can include a replaceable filter engagement mechanism with a replaceable filter engagement surface that is congruent to the manifold engagement surface. The method can also include sliding the filter engagement surface against the second horizontal portion, sliding the filter engagement surface against the angled portion after sliding the filter engagement surface against the second horizontal portion, and sliding the filter engagement surface against the first horizontal portion after sliding the filter engagement surface against the angled portion. 
         [0014]    In a fourth aspect a filter cartridge includes a filter body, a filter media disposed within the filter body, and a neck portion having a fluid inlet and a fluid outlet. A cartridge engagement mechanism on the neck portion is configured for engaging a manifold assembly with a manifold attachment member comprising a manifold engagement surface comprising a first horizontal portion, a second horizontal portion, and an angled portion disposed between and joining the first horizontal portion to the second horizontal portion. The cartridge engagement mechanism includes a filter engagement surface that is non-congruent with the manifold engagement surface. 
         [0015]    Various embodiments can include some, all, or none of the following features. The cartridge engagement mechanism on the neck portion can be configured for engaging at least one manifold assembly having a model identifier selected from the group including PureSource Ultra II-M, PureSource Ultra II-U, PureAdvantage Ultra-M, PureAdvantage Ultra-U, GE MSWF, 60820860, 9000 225170, 9000 705475, 9000 777508, 4US-MAXL-S01, 4US-MAXS-S01, 4US-RO-S01, 4US-RO-S01 H, 4WH-Q Series, 4WH-QS-S01, 4WH-QCTO-S01, and 4WH-QSS-S01H. 
         [0016]    In a fifth aspect, a filter cartridge includes a filter body, a filter media disposed within the filter body, and a neck portion having a fluid inlet and a fluid outlet. A cartridge engagement mechanism on the neck portion includes a means for engaging a compatible manifold assembly with a manifold attachment member comprising a manifold engagement surface comprising a first horizontal portion, a second horizontal portion, and an angled portion disposed between and joining the first horizontal portion to the second horizontal portion. 
         [0017]    Various embodiments can include some, all, or none of the following features. The means for engaging a compatible manifold assembly can include a filter engagement surface that is non-congruent with the manifold engagement surface. 
         [0018]    In a sixth aspect, a system includes a manifold assembly including a manifold engagement mechanism having a manifold engagement surface with a first horizontal portion, a second horizontal portion, and an angled portion disposed between and joining the first horizontal portion to the second horizontal portion, and a replacement filter cartridge including a filter body, a filter media disposed within the filter body, a neck portion having a fluid inlet and a fluid outlet, and a cartridge engagement mechanism for engaging the manifold assembly, the cartridge engagement mechanism comprising at least one a filter engagement surface. The replacement filter cartridge is attached to the manifold assembly with the filter engagement surface engaged with the manifold engagement surface and wherein the filter engagement surface is non-congruent to the manifold engagement surface. 
         [0019]    Various embodiments can include some, all, or none of the following features. The filter engagement surface may not include a first filter horizontal portion, a second filter horizontal portion and an angled filter portion disposed between and joining the first filter horizontal portion to the second filter horizontal portion. The at least one filter engagement surface can include first and second filter engagement surfaces on generally opposite sides of the neck portion, wherein the first filter engagement surface can include no more than one horizontal portion. The at least one filter engagement surface includes first and second filter engagement surfaces on generally opposite sides of the neck portion, wherein the first filter engagement surface includes no more than one horizontal portion and an angled portion. The filter engagement surface can includes an arcuate portion. The filter engagement surface can include two separated arcuate surfaces extending from an outer surface of the neck portion and disposed within 180 degrees of rotation on the outer surface, wherein the two arcuate surfaces are spaced axially and circumferentially apart from each other with respect to a centerline axis of the filter cartridge extending in a longitudinal direction. The filter engagement surface can include two posts. The filter engagement surface can include two arcs. The filter engagement surface can include two separated tabs on an outer surface of the neck portion disposed within 180 degrees of rotation on the outer surface and the two separated tabs can be spaced axially and circumferentially apart from each other with respect to a centerline axis of the filter cartridge extending in a longitudinal direction. The manifold assembly can be a manifold assembly having a model identifier selected from the group consisting of PureSource Ultra II-M, PureSource Ultra II-U, PureAdvantage Ultra-M, PureAdvantage Ultra-U, GE MSWF, 60820860, 9000 225170, 9000 705475, 9000 777508, 4US-MAXL-S01, 4US-MAXS-S01, 4US-RO-S01, 4US-RO-S01 H, 4WH-Q Series, 4WH-QS-S01, 4WH-QCTO-S01, and 4WH-QSS-S01 H. 
         [0020]    The systems and techniques described here may provide one or more of the following advantages. First, a system can provide a filter cartridge assembly that is easily removed and replaced by an end-user. The system can provide filter engagement features that can engage with a number of different models of filter manifolds and appliance models. The system can provide a number of different configurations of engagement features that can compatibly engage with filter manifolds having two-stage engagement and disengagement features. 
         [0021]    The details of one or more implementations are set forth in the accompanying drawings and the description below. Other features and advantages will be apparent from the description and drawings, and from the claims. 
     
    
     
       DESCRIPTION OF DRAWINGS 
         [0022]      FIG. 1  is a sectional view of the manifold assembly member of the present disclosure taken through the inlet and outlet ports. 
           [0023]      FIG. 2  is a sectional view of the manifold assembly member of the present disclosure taken perpendicular to  FIG. 1 . 
           [0024]      FIG. 3  is an exploded perspective view of the manifold assembly. 
           [0025]      FIG. 4  is an underside perspective view of the manifold assembly. 
           [0026]      FIG. 5  is a plan view of the cartridge top member. 
           [0027]      FIG. 6  is a perspective view of the cartridge top member, topside. 
           [0028]      FIG. 7  is a perspective view of the cartridge top member, underside. 
           [0029]      FIG. 8  is a cross sectional view of the cartridge top member taken through its center. 
           [0030]      FIG. 9  is an exploded perspective view of the cartridge assembly. 
           [0031]      FIG. 10  is a side elevational sectional view of the cartridge assembly. 
           [0032]      FIG. 11  is a perspective view of the cartridge filter glue dam; and 
           [0033]      FIG. 12  is a plan view of the filter cartridge glue dam. 
           [0034]      FIG. 13  is a perspective, cap-side view of an embodiment of a filter cartridge having a multiple stage attachment mechanism. 
           [0035]      FIG. 14  is a perspective, base-side view of the filter cartridge of  FIG. 13 . 
           [0036]      FIG. 15  is an exploded, perspective view of the filter cartridge of  FIG. 13 . 
           [0037]      FIG. 16  is a side view of the filter cartridge of  FIG. 13 . 
           [0038]      FIG. 17  is an alternative side view of the filter cartridge of  FIG. 13 . 
           [0039]      FIG. 18  is a cap-side end view of the filter cartridge of  FIG. 13 . 
           [0040]      FIG. 19  is a base-side end view of the filter cartridge of  FIG. 13 . 
           [0041]      FIG. 20  is a fragmentary perspective view of the filter cartridge of  FIG. 13  with an expanded view of a filter cap. 
           [0042]      FIG. 21  is a cap-side perspective view of the filter cap of  FIG. 20 . 
           [0043]      FIG. 22  is a fragmentary side view of the filter cartridge of  FIG. 13  with an expanded view of the filter cap of  FIG. 20 . 
           [0044]      FIG. 23  is a section view of the filter cartridge of  FIG. 13  in which the section is taken through the center of the cartridge. 
           [0045]      FIG. 24  is an exploded, perspective view of a distribution manifold. 
           [0046]      FIG. 25  is a filter-connection end view of the distribution manifold of  FIG. 24 . 
           [0047]      FIG. 26  is an inflow-outflow-connection end view of the distribution manifold of  FIG. 24 . 
           [0048]      FIG. 27  is a side view of the distribution manifold of  FIG. 24  with hidden structure shown in phantom lines. 
           [0049]      FIG. 28  is a sectional side view of the distribution manifold of  FIG. 24  taken along line  28 - 28  of  FIG. 27 . 
           [0050]      FIG. 29  is a side view of the distribution manifold of  FIG. 24 . 
           [0051]      FIG. 30  is a section view of the distribution manifold of  FIG. 24  taken at line  30 - 30  of  FIG. 29 . 
           [0052]      FIG. 31  is an exploded, perspective view of a water filtration system comprising the filter cartridge of  FIG. 13  and the distribution manifold of  FIG. 24 . 
           [0053]      FIG. 32  is an alternative exploded, perspective view of the water filtration system of  FIG. 31  with the manifold and filter cartridge aligned for attachment. 
           [0054]      FIG. 33  is a fragmentary, cut-away side view of the water filtration system of  FIG. 31  with a portion of the wall of the manifold cut away to show a portion of the multistage ramp engagement mechanism. 
           [0055]      FIG. 34  is a side view of a multiple-stage ramp engagement mechanism in a disconnected orientation. 
           [0056]      FIG. 35  is a side view of the multiple-stage ramp engagement mechanism of  FIG. 34  in a first partially-engaged orientation. 
           [0057]      FIG. 36  is a side view of the multiple-stage ramp engagement mechanism of  FIG. 34  in a second partially-engaged orientation. 
           [0058]      FIG. 37  is a side view of the multiple-stage ramp engagement mechanism of  FIG. 34  in a third partially-engaged orientation. 
           [0059]      FIG. 38  is a side view of the multiple-stage ramp engagement mechanism of  FIG. 34  in a fully engaged orientation. 
           [0060]      FIG. 39  is a side, perspective view of an adapter for adapting the manifold assembly of  FIG. 1  to accept the filter cartridge of  FIG. 13 . 
           [0061]      FIG. 40  is an exploded, perspective view of a distribution manifold and a filter cartridge having a linear multi-stage interconnection mechanism. 
           [0062]      FIG. 41A  is a fragmentary perspective view of an embodiment of the filter cartridge of  FIG. 13  with an expanded view of another example filter cap. 
           [0063]      FIG. 41B  is a fragmentary side view of an embodiment of the filter cartridge of  FIG. 13  with an expanded view of the filter cap of  FIG. 41A . 
           [0064]      FIG. 42A  is a fragmentary perspective view of an embodiment of the filter cartridge of  FIG. 13  with an expanded view of another example filter cap. 
           [0065]      FIG. 42B  is a fragmentary side view of an embodiment of the filter cartridge of  FIG. 13  with an expanded view of the filter cap of  FIG. 42A . 
           [0066]      FIG. 43A  is a fragmentary perspective view of an embodiment of the filter cartridge of  FIG. 13  with an expanded view of another example filter cap. 
           [0067]      FIG. 43B  is a fragmentary side view of an embodiment of the filter cartridge of  FIG. 13  with an expanded view of the filter cap of  FIG. 43A . 
           [0068]      FIG. 44A  is a fragmentary perspective view of an embodiment of the filter cartridge of  FIG. 13  with an expanded view of another example filter cap. 
           [0069]      FIG. 44B  is a fragmentary side view of an embodiment of the filter cartridge of  FIG. 13  with an expanded view of the filter cap of  FIG. 44A . 
           [0070]      FIG. 45A  is a fragmentary perspective view of an embodiment of the filter cartridge of  FIG. 13  with an expanded view of another example filter cap. 
           [0071]      FIG. 45B  is a fragmentary side view of an embodiment of the filter cartridge of  FIG. 13  with an expanded view of the filter cap of  FIG. 45A . 
           [0072]      FIG. 46A  is a fragmentary perspective view of an embodiment of the filter cartridge of  FIG. 13  with an expanded view of another example filter cap. 
           [0073]      FIG. 46B  is a fragmentary side view of an embodiment of the filter cartridge of  FIG. 13  with an expanded view of the filter cap of  FIG. 46A . 
           [0074]      FIG. 47  is a flow diagram of an example process for replacing a filter cartridge. 
       
    
    
     DETAILED DESCRIPTION 
       [0075]    An example filter assembly or point-of-use water filtration system of the present disclosure is shown generally at  10  in the figures. The filter assembly  10  includes two major components: a manifold assembly  12  and a cartridge assembly  14 . The cartridge assembly  14  includes three major subcomponents: a cartridge top member  16 , a cartridge housing  18 , and a filter element  19 . 
         [0076]    As illustrated in  FIGS. 1, 2, 3, and 4 , the manifold assembly  12  includes a manifold assembly body  20 . An inlet cartridge fitting  23  is press-fit into an inlet bore  21  of the manifold assembly body  20 , forming an inlet port  22 . A gap  27 , illustrated in  FIG. 1 , is formed between the inlet bore  21  and the inlet cartridge fitting  23 . The inlet port  22  is sealed from a gap  27  by means of an O-ring  30  or the like. The inlet port  22  narrows into a tubular inlet flow passage  29 . The inlet flow passage  29  leads to a valve well  42 . The valve well  42  is positioned to accept both a high-flow valve  28  and a biasing spring  26 . The valve well  42  is fluidly operatively connected to an inlet bore  52  of a cartridge insert  50  (see  FIG. 3 ). The high-flow valve  28  is seated in and also longitudinally translates within the valve well  42 . The inlet bore  52  has an annular surface  37  upon which a ridge  33  of the high-flow valve  28  sits to create a substantially water-tight seal when the biasing spring  26  is decompressed. 
         [0077]    From  FIG. 3 , the cartridge insert  50  has two main sections, an expanded upper body portion  54  and a second reduced body portion  56 . The body portion  56  has a significantly reduced diameter when compared to the diameter of an upper body portion  54 . The cartridge insert  50  is fixedly operatively connected to a base assembly  43  of the manifold assembly  12  at a sealing surface  47 , as shown in  FIG. 4 . The cartridge insert  50  and the base assembly  43  are substantially sealed therein by a gasket  48  or the like, which separates pressurized inlet and outlet water from the cavity of the manifold assembly body  20 . The base assembly  43  is operatively connected with the cartridge insert  50  and fluidly connects an outlet  44  of the manifold assembly  20  with and inlet bore  52  of the cartridge insert  50 , as well as an inlet  46  of the manifold assembly  20  with an outlet bore  40  of the cartridge insert  50 . 
         [0078]    An expanded upper body portion  54  includes a groove  38 . The groove  38  includes a seal  34 , such as an O-ring, for substantially sealing pressurized water from within a receiver well  106  of the cartridge top member  16  (shown in  FIG. 6  and described below) from the cavity of the manifold assembly body  20 . The reduced body portion  56  also includes a pair of grooves  36 . The grooves  36  are arranged in series and hold a collection of seals  32 , such as O-rings, to separate unfiltered inlet water within the receiver well  106  from filtered outlet water. The reduced body portion  56  also has bored through its longitudinal center an outlet bore  40  for conveying filtered outlet water from the cartridge assembly  14 . 
         [0079]    Turning now to  FIG. 3 , the outlet bore  40  continues through the expanded upper body portion  54  by means of a conical projection  59  within which filtered outlet water flows. The conical projection  59  has a wider diameter at its base than its peak, the base therefore narrowing to its point of fluid coupling with an outlet flow passage  31 . The outlet bore  40  retains a substantially constant inside diameter flow path. From  FIG. 1 , the flow passage  31  has an approximate 90-degree turn leading to an outlet flow passage  35 . As before, the outlet port  24  is formed from the press-fitting of the outlet cartridge fitting  25  into the outlet bore  39  of the manifold assembly body  20 . A similar sealing means of an O-ring  30  is employed to seal the subsequent gap  27  formed between the outlet cartridge fitting  25  and the outlet bore  39 . 
         [0080]    The manifold assembly  12  also includes a top manifold hood  62  attached to the manifold assembly body  20  using a collection of manifold hood connectors  60  as shown in  FIG. 3 . 
         [0081]    Referring to  FIG. 4 , the underside of the manifold assembly body  20  has protruding therefrom a cartridge receiver  72  for operatively connecting with the cartridge top member  16 . The operatively connecting mechanism between the cartridge receiver  72  and the cartridge top member  16  is through a collection of interior helical tabs  70  located on the inside margin  73  of the cartridge receiver  72 . The tabs  70  are diametrically opposed on the inside margin  73 . The tabs  70  extend flush from the bottom surface of the receiver  72  and spiral upward at an approximate 8-degree angle along the margin  73  to a position less than half the circumference away from their point of origin. The top surface  74  of the tabs  70  provides the supporting structure for and operatively connects with a collection of external helical tabs  104  of the cartridge top member  16 , shown in  FIG. 6  and described below. 
         [0082]    Turning now to  FIGS. 6 and 7 , cartridge top member  16  includes member body  100 . The cartridge top member  16  provides a neck portion having a fluid inlet and a fluid outlet. Member body  100  has a margin  101  from which a collection of exterior helical tabs  104  operatively connect with the interior helical tabs  70  of cartridge receiver  72 . As with the interior helical tabs  70 , the exterior helical tabs  104  spiral upward at an approximate 8-degree angle along the margin  101  to a position less than approximately half the circumference away from their point of origin. An underside surface  128  of these tabs is supported by a top surface  74  of the interior helical tabs  70  of manifold assembly  12 , shown in  FIG. 4 . As can be seen in  FIGS. 6 and 7 , each of the exterior helical tabs  104  has at its end point a ramp  120  for facilitating engagement with the interior helical tabs  70 . 
         [0083]    The cartridge top member body  100  has defined therein an interior receiver well  106  with an inside margin  112  for substantially sealing with an O-ring  34  of the manifold assembly  12  as shown in  FIG. 1 . This substantially effects a fluid seal between unfiltered inlet water within the receiver well  106  and the cavity of the manifold assembly body  20 . 
         [0084]    As illustrated  FIGS. 5, 6, 7, and 8 , a collection of inlet orifices  114  are formed within the bottom surface of the receiver well  106 . The orifices  114  are spaced circumferentially and substantially equidistant from each other, although any other appropriate spacing and numbers of orifices can be used. In some embodiments, the inside diameter of any individual orifice can be designed such that the adhesive forces between the inside surface and any remaining water within that orifice may allow for capillary action to prevent dripping when the cartridge assembly  14  is disengaged from the manifold assembly  12 . The orifices  114  direct inlet water to the cartridge housing  18 . 
         [0085]    An outlet bore  122  is bored through the center of the cartridge top member  16 . Within the outlet bore  122 , the reduced body portion  56  of the cartridge insert  50  is engaged for conveyance of filtered water. A lip  124  protrudes from the underside of the outlet bore  122 , positioning the filter  19  within the cartridge assembly  14 . Two of the ramps  102  extend upward from the bottom of the receiver well  106 . One or the other of the ramps  102  radially aligns with a high-flow valve  28  contact surface  41  to compress and open the valve  28  when the cartridge top member  16  is rotatably moved into place to operatively connect with the manifold assembly  12 . 
         [0086]    The underside surface  128  of each of the helical tabs  104  has a locking tab  108  for operatively connecting with a cooperative depression  109  located in the interior helical tab  70  of the manifold assembly  12 . In some embodiments, the locking tabs  108  can interface with a collection of depressions  109  during engagement of the cartridge assembly  14  with the manifold assembly  12  to lock the cartridge assembly  14  in place and to provide a degree of burst protection to the components of the filter assembly  10 , for example to resist unexpected disconnection of the cartridge assembly  14  from the manifold assembly  12 . In some embodiments, the locking tabs  108  can disengage from the respective depressions  109  permitting the cartridge assembly  14  to back off from the manifold assembly  12  at a predefined level of hydraulic pressure for the benign disengagement thereof. 
         [0087]    Referring to  FIGS. 4 and 6 , the manifold assembly  12  and the cartridge top member  16  have alignment markers,  200  and  202  respectively, to indicate alignment of both components and engagement of the locking tabs  108 . 
         [0088]    As illustrated in  FIG. 7 , the cartridge top member  16  has an exterior face  116  extending circumferentially from the body  100 . The interior face  117  of the exterior face  116  progressively slopes centerward to the inlet orifices  114 . In some embodiments, this slope can allow for a smoother transition and flow pattern from the interior space within the exterior face  116 . Also on the interior face  117  are two weld facilitators  118 . The weld facilitators  118  are diametrically opposed from each other. 
         [0089]    As illustrated in  FIGS. 6 and 8 , defined around the perimeter of upper sealing surface  112  of the receiver well  106  are a collection of vent ports  110 . The vent ports  110  are spaced approximately equidistant around the diameter of the sealing surface  112 . The vent ports  110  separate the surface  112  from the interior cavity of the manifold assembly body  20 , as shown in  FIG. 1 . As will be seen, the vent ports  110  allow for relief of pressure trapped in the cartridge assembly  14  before complete disengagement during the disassembly of the cartridge assembly  14  from the manifold assembly  12 . The top edge  126  of the receiver well  106  is chamfered to facilitate this relief of pressure. 
         [0090]    Turning now to the example cartridge housing assembly  18  as shown in  FIGS. 9 and 10 , the cartridge housing assembly  18  includes a cartridge housing body  150  and its components as well as a filter assembly  19 . The cartridge housing body  150  is a cylindrical housing tapered at one end for insertion of the filter assembly  19 . A collection of lateral supports  154  protrude inward from the bottom of body  150  (e.g., the narrow end) for longitudinally supporting the filter assembly  19  in place. Concentric and center to the supports  154  is an upward directed alignment projectile  156 , also used to support and center the filter assembly  19  within the cartridge housing body  150 . A handle  158  is formed from the bottom of the housing body  150  and is utilized to assist in applying rotational force to the cartridge assembly  14 . 
         [0091]    The filter  19  includes a carbon filter  180  or other type filter. The carbon filter  180  is made of activated carbon with roughly about one micron particle size in a binder. The carbon block forming the carbon filter  180  has an inner margin  191  that defines an axial bore  190 . In the illustrated example, the carbon filter  180  is a molded design as shown in  FIG. 10  in which the axial bore  190  does not extend all the way through the filter  180 , but instead to a point in which a portion of filter medium exists between the end of the axial bore  190  and an alignment projectile  156 . In such examples, the full exterior surface of the filter  180  in fluid contact with the inlet water serves as a filter medium. 
         [0092]    In some embodiments, the filter  19  includes an extruded design in which axial bore  190  does extend all the way through carbon filter  180 . The extruded design includes an end dam on the bottom of the carbon filter  180  to prevent unfiltered water migration into the axial bore  190 . The extruded embodiment is defined by a dashed lines  199  extending through the carbon filter  180 , as shown in  FIG. 10 . 
         [0093]    The outlet of filter element  19  includes an adhesive layer  182  and a glue dam  184 . As shown in  FIGS. 11 and 12 , the glue dam  184  further includes a disc  185 , a collection of supports  186 , and an outlet tube  188 . The disc  185  has a diameter that is less than that of the inside surface of the cartridge housing body  150 , providing a flow path for unfiltered water to the filter  180 , shown as an annular space  152  in  FIG. 10 . To facilitate the flow of water, the outer edge of the disc  185  angles downward via an outer edge  187 . 
         [0094]    The disc  185  also includes a collection of spacers  189  placed approximately equidistant around an outer edge  187 , further defining the annular space available as a path for unfiltered water. A collection of angled supports  186  are spaced approximately equidistant around the top face of the glue dam  184  to brace an outlet tube  188 . The interior surface of the outlet tube  188  provides a sealing surface  192 . The sealing surface  192  is sized to accept one or more O-rings  32  or the like as described above in  FIG. 3  for the purpose of separating unfiltered inlet water from filtered outlet water. The bottom of a sealing surface  192  provides an outlet face  195 . Within the outlet face  195  is a bore defining outlet orifice  194 , for fluidly connecting filtered outlet water of the filter bore  190  to the outlet bore  40  of the cartridge insert  50 . 
         [0095]    As shown in  FIG. 9 , the cartridge top member  16  connects with the cartridge housing assembly  18  through the coupling of the exterior face  116  with the inside surface  196  of the cartridge housing  150 . 
         [0096]    In operation, from an external connection (not shown), unfiltered water flows through the inlet port  22  of  FIG. 1  to the inlet flow passage  29  and into the valve well  42 . When the manifold assembly  12  is not engaged with the cartridge assembly  14 , the biasing spring  26  imparts a force upon the high-flow valve  28 , depressing it from the valve well  42  into the inlet bore  52  of the cartridge insert  50 . This effects a substantially watertight seal at the annular surface  37  between the valve well  42  and the inlet bore  52  of the cartridge insert  50 . 
         [0097]    In coupling operation, the manifold assembly  12  is engaged with the cartridge assembly  14  and specifically, the cartridge top member  16  as follows. The manifold assembly  12  is engaged with the cartridge assembly  14  by matching up the external helical tabs  104  of the cartridge top member  16  with the internal helical tabs  70  of the manifold assembly  12 , using one or more of the ramps  120  as an initial guide. The operatively connecting helical tabs  70 ,  104  will begin to engage the manifold assembly  12  with the cartridge assembly  14  when a rotational motion is imparted to the cartridge assembly  14  relative to the manifold assembly  12 . This rotational motion will translate into a longitudinal displacement of the cartridge assembly  14  into the manifold assembly  12 , substantially sealing both the interior sealing surface  192  of the outlet tube  188  on  FIG. 8 , as well as the sealing surface  112  of the cartridge top member  16 . 
         [0098]    When the alignment marker  200  of the manifold assembly  12  (see  FIG. 4 ) is lined up with the alignment marker  202  of the cartridge top member  16  (see  FIG. 6 ), then the ramp  102  of the cartridge top member  16  will have depressed the high-flow valve  28  within the valve well  42  of the manifold assembly  12  against the compressive force of the biasing spring  26 . This allows inlet water to flow through as described above. The alignment of the markers  200  and  202  also indicates that the locking tabs  108  have engaged the depressions  109 . 
         [0099]    During normal engagement, as described below, the axial force imparted on the high-flow valve  28  by the ramps  102  of the cartridge top member  16  translates through the body of the valve  28 , compressing the biasing spring  26  and allowing inlet water to flow from the inlet flow passage  29  through to the receiver well  106  of the cartridge top member  16 . 
         [0100]    Within the receiver well  106 , pressurized water flows through the inlet bores  114  (see  FIG. 6 ) along the interior surface  117  of  FIG. 7  and guided around to the outer circumference of the disc  185  and down an outer edge  187  of  FIG. 9 . Flow proceeds into the annular space  152  defined between the exterior of the filter  180  and the interior surface of the cartridge housing  150  as shown in  FIG. 10 . Differential pressure between the exterior of the filter  180  and the axial bore  190  forces this inlet water from the annular space  152  through the filter to the axial bore  190 . From the axial bore  190 , filtered water now flows through the flow restriction outlet orifice  194  through the outlet bore  40  of the cartridge insert  50  to the outlet flow passage  31  of the manifold assembly  12 . From there, filtered water exits the manifold assembly  12  through the outlet flow passage  35  and out the outlet port  24  to an external means connected thereto (not shown). 
         [0101]    In some embodiments, an adapter can be used to facilitate interconnection of the cartridge assembly  14  and the manifold assembly  12 . Such an adapter can allow for the use of filter assembly components  10  not originally designed for use with one another. 
         [0102]    The disengagement of the manifold assembly  12  from the cartridge assembly  14  proceeds as follows. With the alignment marker  200  of the manifold assembly  12  aligned with the alignment marker  202  of the cartridge top member  16 , at 0 degrees. In some examples, relative rotational motion between the manifold assembly  12  and the cartridge assembly  14  may also provide relative motion along the longitudinal axis. As rotational force is applied to the cartridge assembly  14  to disengage it from the manifold assembly  12 , from 0 degrees to substantially 17 degrees from alignment, the locking tabs  108  are unseated from the depressions  109 . Simultaneously, the compressive force of the biasing spring  26  acts to close the high-flow valve  28  as the valve  28  rides down the ramp  102  (see  FIG. 6 ). As valve  28  descends (longitudinal relative motion), the ridge  33  approaches the annular sealing surface  37 . At substantially 17 degrees of rotation, the biasing spring  26  presses the ridge  33  of the high-flow valve  28  into contact with the annular sealing surface  37 , thereby stopping the flow of inlet water to the cartridge assembly. As rotation proceeds, at substantially 34 degrees from alignment, the sealing surface  112  begins to disengage longitudinally from the O-ring  34 , thus opening the vent ports  110  to ambient pressure and allowing the vent ports  110  to relieve excess pressure within the cartridge assembly  14 . As separation of the cartridge assembly  14  from the manifold assembly  20  advances at approximately 120 degrees from alignment, the cartridge assembly  14  will be free to fully disengage from the manifold assembly  12 . 
         [0103]    In some embodiments, the locking tabs  108  and the depressions  109  can retain a connection between the manifold assembly  12  and the cartridge assembly  14  under predetermined pressures and flows as described above, and can be manually disengaged in order to separate the manifold assembly  12  from the cartridge assembly  14  (e.g., to facilitate replacement of the cartridge assembly  14 ). In some embodiments, upon an overpressure condition within the filter assembly, internal pressure can unseat the locking tabs  108  from the depressions  109  without manual intervention and cause disengagement of the cartridge assembly  14  from the manifold assembly  12 . 
         [0104]    Referring to  FIGS. 13-23 , a representative embodiment of a filter cartridge  300  comprising a filter cap  302 , a filter media  303  and a filter body  304  is illustrated in which the filter cartridge can be used to compete a two stage engagement structure. In general, the filter cap provides a neck having a fluid inlet and a fluid outlet. The filter media  303  can include a wide variety of filtering medias, for example, depth filtration media, surface filtration media, sand filtration media, activated carbon filtration media, ion exchange filtration media, cross-flow membrane filtration media, and hollow fiber filtration media. The filter cap  302  and the filter body  304  can be fabricated of suitable polymeric materials such as polypropylene, polycarbonate or polyethylene. Alternatively, the filter cartridge  300  can be fabricated from modified polyolefins such as, for example, metallocene modified polypropylene or polyethylene polymers and copolymers, as well as either high or low density polyethylene polymers, having properties such as increased strength, elasticity or increased elongation percentages such as disclosed in U.S. patent application Ser. No. 10/377,022, published as U.S. Pat. Pub. No. 2004/0094468 A1, which is herein incorporated by reference to the extent not inconsistent with the present disclosure. In some embodiments, the filter cap  302  may be constructed of a first polymer, such as polypropylene, having a specific quality such as, for example, strength or rigidity while the filter body  304  is constructed of a second polymer having a different design quality such as, for example, increased elongation percentage or increased stretch. Examples of suitable polymers include metallocene modified polypropylene or polyethylene polymers and copolymers as well as either high or low density polyethylene polymers. The filter cap  302  and the filter body  304  are operatively joined using any suitable joining technique such as, for example, an engageable thread  305  as illustrated in  FIG. 15  or, for example, other joining techniques such as adhesives, heat welding, spin welding, ultrasonic welding and any other appropriate means for joining components. The filter cartridge  300  generally comprises an attachment end  306  and a handling end  308 . 
         [0105]    The filter cap  302  can include a pair of opposed and identically configured multi-stage filter attachment members  310   a ,  310   b , for example attachment ramps as illustrated in  FIGS. 13-23 . As illustrated in  FIGS. 17, 20 and 21 , the multi-stage filter attachment members  310   a ,  310   b  include a first angled portion  312   a  adjacent to a first horizontal portion  314   a , the first horizontal portion  314   a  facing toward the filter body, a second angled portion  316   a  adjacent to the first horizontal portion  314   a , a second horizontal portion  318   a  facing toward the filter body, and a third angled portion  319   a  adjacent to the second horizontal portion  318   a . The multi-stage filter attachment member  310   b  can include a first angled portion  312   b , a first horizontal portion  314   b , a second angled portion  316   b , a second horizontal portion  318   b  and a third angled portion  319   b.    
         [0106]    As illustrated in  FIGS. 18, 20, 21 and 23 , the filter cap  302  comprises a projecting insertion wall  320 . A plurality of venting notches  322  is spaced about the inner rim of the insertion wall  320 , although a single vent or a different number of venting notches can be used relative to the venting notches shown in the figures. The filter cap  302  further comprises an interface surface  324  having a plurality of feed throughbores  326  and a return throughbore  328 . As illustrated, the interface surface  324  also includes a pair of arcuate kick-off ramps  330   a ,  330   b.    
         [0107]    Referring now to  FIGS. 24-30 , an embodiment of a distribution manifold  332  configured for operable interfacing with the filter cartridge  300  is illustrated. The distribution manifold  332  generally comprises a filter end  334  and a distribution end  336 , although alternative embodiments can have distribution connections along a side and/or in the same general direction as the filter end  334 . In some embodiments, the distribution manifold  332  can be constructed of the same polymeric material as filter cartridge  300 . In some embodiments, the distribution manifold  332  can include a material selected for qualities such as strength, rigidity, cost, and/or ease of fabrication. As illustrated in  FIGS. 26, 29 and 30 , the distribution end  336  includes a pair of tube connectors  338   a ,  338   b  for interconnection to a feed water tube  340  and a filtered water tube  342 . As illustrated in  FIGS. 25, 29 and 30 , the filter end  334  includes an exterior wall  344 , an engagement surface  346  and an engagement body  348 . The engagement surface  346  includes a feed throughbore  347   a , configured to operatively accept a feed valve assembly  349 , and a return throughbore  347   b . The feed valve assembly  349  includes a valve body  349   a  and a spring  349   b . The engagement body  348  includes a projecting member  350 , a projecting feed throughbore  351   a , a projecting return throughbore  351   b , a pair of projection grooves  352   a ,  352   b , a pair of projection seals  353   a ,  353   b , a circumferential groove  354 , and a circumferential seal  355 . The engagement body  348  is operatively connected to engagement surface  346  such that a feed fluid circuit  357   a  is defined by the projecting feed throughbore  351   a , the feed throughbore  347   a , the tube connector  338   a  and feed water tube  340  while a filtered fluid circuit  357   b  is defined by the projecting return throughbore  351   b , the return throughbore  347   b , the tube connector  338   b  and filtered water tube  342 . Return throughbore  351   b  is fluidly interconnected with the filtered water tube  342  while the feed throughbore  347  is fluidly interconnected with the feed water tube  340 . 
         [0108]    In some embodiments, the manifold  332  can be a refrigerator manifold assembly. For example, the manifold  332  can be a manifold assembly of a filter system model listed in TABLE 1, or any other appropriate manifold assembly for a refrigerator, under-sink water filtration system, or other appliance. In some embodiments, the filter cartridge  300  can replace a filter cartridge having a model number listed in TABLE 1. 
         [0000]    
       
         
               
               
               
               
             
           
               
                   
                 TABLE 1 
               
               
                   
                   
               
               
                   
                   
                   
                 Replacement 
               
               
                   
                 Manufacturer 
                 Filter System Model 
                 Filter Model 
               
               
                   
                   
               
             
             
               
                   
                 Electrolux 
                 PureSource Ultra II-M 
                 EPTWFU01 
               
               
                   
                   
                 PureSource Ultra II-U 
               
               
                   
                   
                 PureAdvantage Ultra-M 
                 EWF02 
               
               
                   
                   
                 PureAdvantage Ultra-U 
               
               
                   
                 GE 
                 GE MSWF 
                 MSWF 
               
               
                   
                 Haier 
                 60820860 
                 60218743 
               
               
                   
                 Bosch 
                 9000 225170 
                 9000 674655 
               
               
                   
                   
                 9000 705475 
               
               
                   
                   
                 9000 777508 
               
               
                   
                 3M 
                 4US-MAXL-S01 
                 4US-MAXL-F01 &amp; 
               
               
                   
                   
                 4US-MAXS-S01 
                 4US-MAXS-F01 
               
               
                   
                   
                 4US-RO-S01 
                 4US-RO-POST 
               
               
                   
                   
                 4US-RO-S01H 
                 4US-RO-POSTH 
               
               
                   
                   
                 4WH-Q Series 
                 4WH-QCTO-F01 
               
               
                   
                   
                 4WH-QS-S01 
                 4WH-QS-F01 
               
               
                   
                   
                 4WH-QCTO-S01 
                 4WH-QCTO-F01 
               
               
                   
                   
                 4WH-QSS-S01H 
                 4WH-QSS-F01H 
               
               
                   
                   
               
             
          
         
       
     
         [0109]    As illustrated in  FIGS. 25, 28 and 33 , the filter end  334  comprises a pair of multi-stage manifold attachment members  356   a ,  356   b , illustrated as attachment ramps, on an interior perimeter wall  359  of the distribution manifold  332 . The manifold attachment members  356   a ,  356   b  are configured correspondingly to the multi-stage filter attachment members  310   a ,  310   b  such that the manifold attachment member  356   a  includes a first angled portion  358   a , a first horizontal portion  360   a , a second angled portion  362   a , second horizontal portion  364   a  and third angled portion  365   a  while the manifold attachment member  356   b  similarly comprises a first angled portion  358   b , a first horizontal portion  360   b , a second angled portion  362   b , second horizontal portion  364   b  and third angled portion  365   b . The multi-stage filter attachment members  310   a ,  310   b  provide a pair of filter engagement surfaces. 
         [0110]    In some embodiments, the filter engagement surfaces may not include a first filter horizontal portion, a second filter horizontal portion, and an angled filter portion disposed between and joining the first filter horizontal portion to the second filter horizontal portion. In some embodiments, the at least one filter engagement surface may include a first and a second filter engagement surface on generally opposite sides of the filter cap  302  (e.g., the neck portion), and the first filter engagement surface may include no more than one horizontal portion or even no horizontal portions. Embodiments such as these will be discussed further in the descriptions of  FIGS. 41A-46B . 
         [0111]    In order to provide filtered water, the filter cartridge  300  is operatively connected to the distribution manifold  332  to form a filtration system  366 , as illustrated in an example disconnected configuration in  FIGS. 31, 32 and 33 . First, the attachment end  306  is oriented to face the filter end  334 , as shown in  FIGS. 32 and 33 . The filter cartridge  300  is directed toward the distribution manifold  332  such that the insertion wall  320  enters the interior space defined by the exterior wall  344 . The projecting member  350  is aligned with the return throughbore  328 . In such a configuration, the filter attachment members  310   a ,  310   b  are in proximity to the manifold attachment members  356   a ,  356   b , for example as illustrated in  FIG. 34 . While engagement of the filter attachment members  310   a ,  310   b  and the manifold attachment members  356   a ,  356   b  is illustrated with respect to the filter attachment member  310   a  and the manifold attachment member  356   a , in some embodiments the filter attachment member  310   b  and the manifold attachment member  356   b  can engage in a like manner. In some embodiments both of the filter attachment members  310   a ,  310   b  and the manifold attachment members  356   a ,  356   b  can be configured in an opposed relation such that the filter attachment member  310   a  can engage similarly with both of the manifold attachment members  356   a ,  356   b  while the filter attachment member  310   b  can also engage with both of the manifold attachment members  356   a ,  356   b . In some alternative embodiments, there can be instances in which one operable orientation is desired for the filter cartridge  300  to operatively connect to the distribution manifold  332  to form the filtration system  366 . One example can include the filtration system  366  utilizing crossflow filtration media with the filter cartridge  300 , such as, for example, membrane or hollow-fiber based crossflow filtration systems as disclosed in U.S. patent application Ser. No. 10/838,140, published as U.S. Pat. Pub. No. 2004/0251192, which is herein incorporated by reference to the extent not inconsistent with the present disclosure. 
         [0112]    As illustrated in  FIG. 34 , the filter attachment member  310   a  and the manifold attachment member  356   a  can be positioned such that the first angled portion  312   a  is in proximity to the first angled portion  358   a . In use, an installer can rotatably direct the handling end  308  such that the filter cartridge  300  may be rotatably inserted with respect to the distribution manifold  332 . As the first angled portion  312   a  and the first angled portion  358   a  engage each other, the filter cartridge  300  and distribution manifold  332  are drawn closer together. As the filter cartridge  300  is rotated further, the first horizontal portion  314   a  and the first horizontal portion  360   a  are directed into intimate contact as shown in  FIG. 35 . In some implementations, this configuration may correspond with the first engagement stage and can be a stable engagement position. 
         [0113]    As the filter cartridge  300  is rotated further, the first angled portion  312   a  interfaces with the second angled portion  362   a  while the second angled portion  316   a  engages the first angled portion  358   a  as shown in  FIG. 36 , thus, further drawing together the filter cartridge  300  and the distribution manifold  332  such that the projection seals  353   a ,  353   b  sealingly engage the wall surrounding the return throughbore  328  while the circumferential seal  355  sealingly engages the interior perimeter surface of the projecting insertion wall  320 . Continued rotation of the filter cartridge  300  causes the first horizontal portion  314  to slidingly contact the second horizontal portion  364   a  while the second horizontal portion  318   a  engages the first horizontal portion  360   a , as shown in  FIG. 37 . In some implementations, this configuration can be the second engagement stage. It will be understood by a person of skill in the art that horizontal portions are substantially horizontal in that they provide resistance against rotation in response to predetermined operating pressures exerted on the filter cartridge. Attachment of the filter cartridge  300  to the distribution manifold  312  is complete when the first angle portion  312   a  seats against the third angled portion  365   a  while the third angle portion  319   a  engages the first angle portion  358   a , as illustrated in  FIG. 38 . As the filter cartridge  300  and the distribution manifold  312  approach an installed position, one of the arcuate kick-off ramps  330   a ,  330   b  engages the feed valve assembly  349  such that the spring  349   b  is compressed and the feed fluid circuit  357   a  is opened to incoming water. As the rotation of filter cartridge  300  is completed, the filter cartridge  300  and the distribution manifold  332  cannot disengage without rotating the filter cartridge  300  in a direction opposed to that indicated in  FIGS. 40-44 . 
         [0114]    In operation, feed water flows through the feed flow circuit  357   a  into the filter cartridge  300 . The feed water is directed through the filter media  303  such that selected contaminants such as, for example, ionic, organic or particulate, are removed from the water such that filtered water is present in the center of the filter media  303 . Purified water flows out of the filter cartridge  300  by way of the return throughbore  328  and the filtered fluid circuit  357   b.    
         [0115]    As illustrated in  FIG. 39 , an adapter  400  can be used to impart features such as, for example, multi-stage engagement mechanisms to water filtration systems lacking such features. The adapter  400  can include a manifold end  402  and a filter end  404 . As shown in  FIG. 39 , the adapter  400  is adapted such that the previously described manifold assembly  12  can accept the filter cartridge  300 . As shown in  FIG. 39 , the manifold end  402  can substantially resemble the cartridge top member  16  while the filter end  404  can substantially resemble the filter end  334 . The manifold end  402  can comprise, for example, a pair of manifold attachment members  406   a ,  406   b , shown in  FIG. 39  as helical engagement members, such that the manifold end  402  is operatively connectable to the manifold assembly  12 . The filter end  404  can include a pair of multi-stage engagement mechanisms  408 , such that the filter end  404  can operatively connectable to the filter cartridge  300 . The manifold end  402  can be adapted such that the adapter  400  remains either permanently operatively connected to the manifold assembly  12  or removal of adapter  400  from manifold assembly  12  requires more torque as compared to removal of the filter cartridge  300  from the filter end  404  such that the adapter  400  need only be attached to the manifold assembly  12  one time. 
         [0116]    In addition to rotational engagement of a filter cartridge to a manifold, a filter cartridge  500  and a distribution manifold  502  can be linearly engaged in a multi-stage manner so as allow venting of any entrained energy within the filter cartridge  500 , for example, as shown in  FIG. 40 . The filter cartridge  500  includes a filter body  504 , a pair of engagement arms  506   a ,  506   b , a filter inlet  508  and a filter outlet  510 . The engagement arms  506   a ,  506   b  include an engagement tab  512 . The filter inlet  508  and the filter outlet  510  can each comprise at least one sealing member  514 . The distribution manifold  502  can comprise a manifold body  516 , a feed supply tube  518 , a distribution tube  520 , a supply bore  522  and a return bore  524 . The supply bore  522  and the return bore  524  can each comprise at least one vent channel  526 . The manifold body  516  includes a first engagement recess  528  and a second engagement recess  530  on each side of the manifold body  516 . 
         [0117]    The filter cartridge  500  is slidably attached to the distribution manifold  502  by directing the filter inlet  508  into the supply bore  522  and the filter outlet  510  into the return bore  524 . The engagement arms  506   a ,  506   b  are configured to slidably advance over the outside of the manifold body  516  until the engagement tab  512  is retainably positioned within the corresponding first engagement recess  528 . At this point, the sealing members  514  sealingly engage the inside perimeters of the supply bore  522  and the return bore  524  such that water to be filtered can flow from the feed supply tube  518 , through the supply bore  522 , into the filter cartridge  500  through the filter inlet  508 , out the filter cartridge  500  through the filter outlet  510  and to points of use through the distribution tube  520 . 
         [0118]    To remove or replace the filter cartridge  500 , a user can slidably directs the filter cartridge  500  away from the distribution manifold  502 . As the engagement tab  512  approaches the second engagement recess  530 , the seal created by the sealing members  514  and the inner perimeter of the supply bore  522  and the return bore  524  are broken allowing any retained energy in the filter cartridge  500  to be released or vented through the vent channel  526 . As the filter cartridge  500  is vented, the filter cartridge  500  is retainably attached to the distribution manifold  502  through the interaction of the engagement tabs  512  and the second engagement recesses  530 . In some embodiments, the fluid connections and engagement structures or portions thereof can be reversed relative to the filter cartridge and the manifold assembly to form other slidably engaging filter assemblies. Similarly, other designs of flow connectors can be effectively used for slidably engaging structures. 
         [0119]    It has now been determined that filters having non-congruent engagement surfaces, structures, or tabs located on the filter can be compatible with the filter manifold depicted in  FIGS. 27-33 . The manifold depicted in  FIGS. 27-33  includes the manifold attachment members  356   a  and  356   b  that are configured to be congruent to the multi-stage filter attachment members  310   a ,  310   b . The manifold attachment member  356   a  includes a first angled portion  358   a , a first horizontal portion  360   a , a second angled portion  362   a , second horizontal portion  364   a  and third angled portion  365   a . While the manifold attachment member  356   b  similarly comprises a first angled portion  358   b , a first horizontal portion  360   b , a second angled portion  362   b , second horizontal portion  364   b  and third angled portion  365   b . A congruent filter includes the multi-stage filter attachment members  310   a ,  310   b . The multi-stage attachment member  310   a  can include a first angled portion  312   a  adjacent to a first horizontal portion  314   a , the first horizontal portion  314   a  facing toward the filter body, a second angled portion  316   a  adjacent to the first horizontal portion  314   a , a second horizontal portion  318   a  facing toward the filter body, and a third angled portion  319   a  adjacent to the second horizontal portion  318   a . The multi-stage filter attachment member  310   b  can include a first angled portion  312   b , a first horizontal portion  314   b , a second angled portion  316   b , a second horizontal portion  318   b  and a third angled portion  319   b . As best seen in  FIG. 38 , when the congruent filter is fully installed into the manifold, the first angled portions ( 358   a ,  319   a ), the first horizontal portions ( 360   a ,  318   a ), the second angled portions ( 362   a ,  316   a ), the second horizontal portions ( 364   a ,  314   a ), and the third angled portions ( 365   a ,  312   a ) of the multi-stage attachment members on both the manifold and the filter are substantially parallel to each other and touching along their respective lengths. A non-congruent filter is any filter engagement surface, structure, or tab that, at least, does not include a first horizontal portion  314 , a second horizontal portion  318 , and a second angled portion  316  disposed between and joining the first horizontal portion  314  to the second horizontal portion  318  as best seen  FIGS. 17 and 25 . 
         [0120]      FIGS. 41A and 41B  are fragmentary perspective and side views of a filter cartridge  4000 , which is an embodiment of the filter cartridge of  FIG. 13  with an expanded view of another example filter cap  4100 . In some embodiments, the filter cap  4100  can be used with the filter cartridge  4000  in place of the filter cap  302 . In some embodiments, some or all of the features of the filter cap  302  not explicitly shown or discussed with respect to the filter cap  4100  may be included in the filter cap  4100  as well. 
         [0121]    In some embodiments, the filter cap  4100  may be used with the filter cartridge  4000  to provide an engagement structure. In some embodiments, the filter cap  4100  may be constructed of a first polymer, such as polypropylene, having a specific quality such as, for example, strength or rigidity. Examples of suitable polymers include metallocene modified polypropylene or polyethylene polymers and copolymers as well as either high or low density polyethylene polymers. In some embodiments, the filter cap  4100  and the filter body  304  may be joined by, for example, an engageable thread or other joining techniques such as adhesives, heat welding, spin welding, ultrasonic welding and any other appropriate means for joining components. In some embodiments, the filter cap  4100  can be integrally formed with the filter body  304  such that the filter cap  4100  is an integral neck portion of the filter body  304 . 
         [0122]    The filter cap  4100  includes a collection of multi-stage filter attachment members  4110   a - 4110   d . The multi-stage filter attachment members  4110   a - 4110   d  are formed as semi-elliptical arcuate ramps or arcs that each include a first end  4112   a  and a second end  4112   b , and an arcuate surface  4114 . In some embodiments, the multi-stage filter attachment members  4110   a - 4110   d  provide a replacement cartridge engagement surface. The arcuate surface  4114  faces the filter body  304  with the peak of the surface directed generally toward the filter body  304 . The multi-stage filter attachment members  4110   a  and  4110   b  are arranged as a pair  4116   a  in relatively proximity to each other, and spaced apart from the multi-stage filter attachment members  4110   c  and  4110   d  which are arranged as a pair  4116   b  generally radially opposed to the pair  4116   a  across the filter cap  4100 . In the illustrated example, the filter engagement surface includes two of the arcuate surfaces  4114  extending from an outer surface of the filter cap  4100  (e.g., the neck portion) and disposed within 180 degrees of rotation on the outer surface. The two arcuate surfaces  4114  are spaced axially and circumferentially apart from each other with respect to a centerline axis of the filter cartridge  4000  and the filter cap  4100  extending in a longitudinal direction. 
         [0123]    In the pair  4116   a , the multi-stage filter attachment member  4110   a  is arranged axially closer to the filter body  304  than the multi-stage filter attachment member  4110   b . In the pair  4116   b , the multi-stage filter attachment member  4110   c  is arranged axially closer to the filter body  304  than the multi-stage filter attachment member  4110   d . The multi-stage filter attachment members  4110   a - 4110   d  form filter engagement surfaces that are non-congruent to the manifold engagement surfaces, e.g., the multi-stage manifold attachment members  356   a ,  356   b . In use, the axially and radially offset relative arrangement of the multi-stage filter attachment members  4110   a - 4110   d  provide surfaces that can engage with the pair of multi-stage manifold attachment members  356   a ,  356   b , illustrated as attachment ramps, on an interior perimeter wall  359  of the distribution manifold  332  of  FIGS. 25, 28 and 33 . The multi-stage filter attachment members  4110   a - 4110   d  can be non-congruent to the manifold engagement surfaces of the multi-stage manifold attachment members  356   a ,  356   b  and yet be suitable for engaging with the manifold engagement surfaces of the multi-stage manifold attachment members  356   a ,  356   b . In some embodiments, the shape and structure of the filter cartridge  4000  and/or the filter cap  4100  can be modified as suitable for the application. For example, in some embodiments the filter cap  4100  can be omitted and the multi-stage filter attachment members  4110   a - 4110   d  can be otherwise connected to the filter cartridge  4000 . 
         [0124]    The multi-stage filter attachment members  4110   a  and  4110   b  are arranged as a pair in relatively proximity to each other, and spaced apart from the multi-stage filter attachment members  4110   c  and  4110   d  which are arranged as a pair generally radially opposed to the pair  4110   a  and  4110   b  across the filter cap  4100  (e.g., the neck portion). Furthermore, the multi-stage filter attachment members are disposed on the neck portion with at least one vent port also located on the neck portion. As seen in the embodiment in  FIG. 41A , two vent ports ( 4119   a  and  4119   b ) are located in the neck portion. The vent ports  4119   a  and  4119   b  are generally radially opposed to each other and approximately orthogonal to the filter attachment members  4110   b  and  4110   c . The vent ports allow for relief of pressure trapped in the filter cartridge before complete disengagement during the removal of the filter cartridge from the manifold. The filter may include an indicium  4120  in some embodiments. In some embodiments, the indicium  4120  can be a label, sticker, stamp, impression, or any other appropriate indicator that can be visible upon the filter cap  4100  or elsewhere on the filter cartridge  4000  or on the filter&#39;s packaging at the point of sale. The indicium  4120  provides compatibility information that indicates the distribution manifolds  332  and/or appliances to which the filter cartridge  4000  can be engaged or that indicates a replaceable filter cartridge. The indicium  4120  can be an indicium selected from the group consisting of a model number and/or other indicium listed in TABLE 1. For example, in one embodiment the indicium  4120  could read “60218743” and in another embodiment the indicium could read “Haier 60218743”. 
         [0125]    The indicium  4120  and the filter cartridge  4000  can be combined as a kit. In some embodiments, the indicium  4120  can be printed directly on the filter cartridge  4000  or can be printed on a label and attached to the filter cartridge  4000 . In some embodiments, the indicium  4120  can be printed on or attached to packaging (not shown) that contains the filter cartridge  4000 . In some embodiments, the indicium can be printed on a label or insert that is packaged with the filter cartridge  4000 . 
         [0126]      FIGS. 42A and 42B  are fragmentary perspective and side views of a filter cartridge  4002 , which is another embodiment of the filter cartridge of  FIG. 13  with an expanded view of another example filter cap  4200 . In some embodiments, the filter cap  4200  can be used with the filter cartridge  4002  in place of the filter cap  302 . In some embodiments, some or all of the features of the filter cap  302  not explicitly shown or discussed with respect to the filter cap  4200  may be included in the filter cap  4200  as well. 
         [0127]    In some embodiments, the filter cap  4200  may be used with the filter cartridge  4002  to provide an engagement structure. In some embodiments, the filter cap  4200  may be constructed of a first polymer, such as polypropylene, having a specific quality such as, for example, strength or rigidity. Examples of suitable polymers include metallocene modified polypropylene or polyethylene polymers and copolymers as well as either high or low density polyethylene polymers. In some embodiments, the filter cap  4200  and the filter body  304  may be joined by, for example, an engageable thread or other joining techniques such as adhesives, heat welding, spin welding, ultrasonic welding and any other appropriate means for joining components. In some embodiments, the filter cap  4200  can be integrally formed with the filter body  304  such that the filter cap  4200  is an integral neck portion of the filter body  304 . 
         [0128]    The filter cap  4200  includes a pair of opposed multi-stage filter attachment members  4210   a ,  4210   b , for example attachment ramps as illustrated in  FIGS. 42A and 42B . In some embodiments, the multi-stage filter attachment members  4210   a  can be identically configured to the multi-stage filter attachment members  4210   b . In some embodiments, the multi-stage filter attachment members  4210   a  can be different than the multi-stage filter attachment members  4210   b . In some embodiments, the multi-stage filter attachment members  4210   a - 4210   b  provide a replacement cartridge engagement surface. The multi-stage filter attachment members  4210   a ,  4210   b  are generally S-shaped curved members that include a curved portion  4212  extending from a first portion  4214   a  that is either horizontal as shown or optionally curved (not illustrated), which faces the filter body, to a second portion  4214   b  that is either horizontal as shown or optionally curved (not illustrated), which also faces the filter body. The first portion  4214   a  is located relatively axially closer to the filter body than the second portion  4214   b . The multi-stage filter attachment member  4210   b  is arranged axially opposite the multi-stage filter attachment member  4210   a  and is not clearly shown in  FIGS. 42A and 42B . The multi-stage filter attachment member  4210   b  is configured substantially the same as the multi-stage filter attachment member  4210   a . In the illustrated example, the filter engagement surface includes the multi-stage filter attachment members  4210   a  and  4310   b  extending from an outer surface of the filter cap  4200  (e.g., the neck portion) and disposed within 180 degrees of rotation on the outer surface. The multi-stage filter attachment members  4210   a  and  4310   b  are spaced axially and circumferentially apart from each other with respect to a centerline axis of the filter cartridge  4002  and the filter cap  4200  extending in a longitudinal direction. 
         [0129]    The multi-stage filter attachment members  4210   a - 4210   b  form filter engagement surfaces that are non-congruent to the manifold engagement surfaces, e.g., the multi-stage manifold attachment members  356   a ,  356   b . In use, the multi-stage filter attachment members  4210   a - 4210   d  provide surfaces that can engage with the pair of multi-stage manifold attachment members  356   a ,  356   b , illustrated as attachment ramps, on an interior perimeter wall  359  of the distribution manifold  332  of  FIGS. 25, 28 and 33 . The multi-stage filter attachment members  4210   a - 4210   b  can be non-congruent to the manifold engagement surfaces of the multi-stage manifold attachment members  356   a ,  356   b  and yet be suitable for engaging with the manifold engagement surfaces of the multi-stage manifold attachment members  356   a ,  356   b . In some embodiments, the shape and structure of the filter cartridge  4002  and/or the filter cap  4200  can be modified as suitable for the application. For example, in some embodiments the filter cap  4200  can be omitted and the multi-stage filter attachment members  4210   a - 4210   b  can be otherwise connected to the filter cartridge  4002 . 
         [0130]    The filter cap  4200  includes the pair of opposed multi-stage filter attachment members  4210   a ,  4210   b , for example attachment ramps as illustrated in  FIGS. 42A . Furthermore, the multi-stage filter attachment members are disposed on the neck portion with at least one vent port also located on the neck portion. As seen in the embodiment in  FIG. 41A , two vent ports ( 4219   a  and  4219   b ) are located in the neck portion. The vent ports  4219   a  and  4219   b  are generally radially opposed to each other and approximately orthogonal to the filter attachment members  4210   a  and  4210   b . The vent ports allow for relief of pressure trapped in the filter cartridge before complete disengagement during the removal of the filter cartridge from the manifold. 
         [0131]    The filter cap  4200  includes an indicium  4220 . In some embodiments, the indicium  4220  can be a label, sticker, stamp, impression, or any other appropriate indicator that can be visible upon the filter cap  4200  or elsewhere on the filter cartridge  4002  or filter packaging. The indicium  4220  provides compatibility information that indicates the distribution manifolds  332  and/or appliances to which the filter cartridge  4002  can be engaged or that indicates a replaceable filter cartridge. The indicium  4220  can be an indicium selected from the group consisting of a model number and/or other indicium listed in TABLE 1. 
         [0132]      FIGS. 43A and 43B  are fragmentary perspective and side views of a filter cartridge  4004 , which is another embodiment of the filter cartridge of  FIG. 13  with an expanded view of another example filter cap  4300 . In some embodiments, the filter cap  4300  can be used with the filter cartridge  4004  in place of the filter cap  302 . In some embodiments, some or all of the features of the filter cap  302  not explicitly shown or discussed with respect to the filter cap  4300  may be included in the filter cap  4300  as well. 
         [0133]    In some embodiments, the filter cap  4300  may be used with the filter cartridge  4004  to provide an engagement structure. In some embodiments, the filter cap  4300  may be constructed of a first polymer, such as polypropylene, having a specific quality such as, for example, strength or rigidity. Examples of suitable polymers include metallocene modified polypropylene or polyethylene polymers and copolymers as well as either high or low density polyethylene polymers. In some embodiments, the filter cap  4300  and the filter body  304  may be joined by, for example, an engageable thread or other joining techniques such as adhesives, heat welding, spin welding, ultrasonic welding and any other appropriate means for joining components. In some embodiments, the filter cap  4300  can be integrally formed with the filter body  304  such that the filter cap  4300  is an integral neck portion of the filter body  304 . 
         [0134]    The filter cap  4300  includes a collection of multi-stage filter attachment members  4310   a - 4310   d . The multi-stage filter attachment members  4310   a - 4310   d  are formed as rounded or elliptical posts projecting radially outward from an attachment end  4306 . The multi-stage filter attachment members  4310   a  and  4310   b  are arranged as a pair  4316   a  in relatively proximity to each other, and spaced apart from the multi-stage filter attachment members  4310   c  and  4310   d  which are arranged as a pair  4316   b  generally radially opposed to the pair  4316   a  across the filter cap  4300 . In some embodiments, the multi-stage filter attachment members  4310   a - 4310   d  provide a replacement cartridge engagement surface. In the illustrated example, the filter engagement surface includes the pairs  4316   a  and  4316   b  extending from an outer surface of the filter cap  4300  (e.g., the neck portion) and disposed within 180 degrees of rotation on the outer surface. The pairs  4310   a  and  4310   b  are spaced axially and circumferentially apart from each other with respect to a centerline axis of the filter cartridge  4004  and the filter cap  4300  extending in a longitudinal direction. 
         [0135]    In the pair  4316   a , the multi-stage filter attachment member  4310   a  is arranged axially closer to the filter body than the multi-stage filter attachment member  4310   b . In the pair  4316   b , the multi-stage filter attachment member  4310   c  is arranged axially closer to the filter body than the multi-stage filter attachment member  4310   d . The multi-stage filter attachment members  4310   a - 4310   d  form filter engagement surfaces that are non-congruent to the manifold engagement surfaces, e.g., the multi-stage manifold attachment members  356   a ,  356   b . In use, the axially and radially offset relative arrangement of the multi-stage filter attachment members  4310   a - 4310   d  provide surfaces that can engage with the pair of multi-stage manifold attachment members  356   a ,  356   b , illustrated as attachment ramps, on an interior perimeter wall  359  of the distribution manifold  332  of  FIGS. 25, 28 and 33 . The multi-stage filter attachment members  4310   a - 4310   d  can be non-congruent to the manifold engagement surfaces of the multi-stage manifold attachment members  356   a ,  356   b  and yet be suitable for engaging with the manifold engagement surfaces of the multi-stage manifold attachment members  356   a ,  356   b . In some embodiments, the shape and structure of the filter cartridge  4004  and/or the filter cap  4300  can be modified as suitable for the application. For example, in some embodiments the filter cap  4300  can be omitted and the multi-stage filter attachment members  4310   a - 4310   d  can be otherwise connected to the filter cartridge  4004 . 
         [0136]    The multi-stage filter attachment members  4310   a - 4310   d  are formed as rounded or elliptical posts projecting radially outward from an attachment end  4306 . Furthermore, the multi-stage filter attachment members are disposed on the neck portion with at least one vent port also located on the neck portion. As seen in the embodiment in  FIG. 43A , two vent ports ( 4319   a  and  4319   b ) are located in the neck portion. The vent ports  4319   a  and  4319   b  are generally radially opposed to each other and between multi-stage filter attachment members  4310   b  and  4310   d . The vent ports allow for relief of pressure trapped in the filter cartridge before complete disengagement during the removal of the filter cartridge from the manifold. 
         [0137]    The filter cap  4300  includes an indicium  4320 . In some embodiments, the indicium  4320  can be a label, sticker, stamp, impression, or any other appropriate indicator that can be visible upon the filter cap  4300  or elsewhere on the filter cartridge  4004 . The indicium  4320  provides compatibility information that indicates the distribution manifolds  332  and/or appliances to which the filter cartridge  4004  can be engaged or that indicates a replaceable filter cartridge. The indicium  4320  can be an indicium selected from the group consisting of a model number and/or other indicium listed in TABLE 1. 
         [0138]      FIGS. 44A and 44B  are fragmentary perspective and side views of a filter cartridge  4006 , which is another embodiment of the filter cartridge of  FIG. 13  with an expanded view of another example filter cap  4400 . In some embodiments, the filter cap  4400  can be used with the filter cartridge  4006  in place of the filter cap  302 . In some embodiments, some or all of the features of the filter cap  302  not explicitly shown or discussed with respect to the filter cap  4400  may be included in the filter cap  4400  as well. 
         [0139]    In some embodiments, the filter cap  4400  may be used with the filter cartridge  4006  to provide an engagement structure. In some embodiments, the filter cap  4400  may be constructed of a first polymer, such as polypropylene, having a specific quality such as, for example, strength or rigidity. Examples of suitable polymers include metallocene modified polypropylene or polyethylene polymers and copolymers as well as either high or low density polyethylene polymers. In some embodiments, the filter cap  4400  and the filter body  304  may be joined by, for example, an engageable thread or other joining techniques such as adhesives, heat welding, spin welding, ultrasonic welding and any other appropriate means for joining components. In some embodiments, the filter cap  4400  can be integrally formed with the filter body  304  such that the filter cap  4400  is an integral neck portion of the filter body  304 . 
         [0140]    The filter cap  4400  includes a pair  4416   a  of multi-stage filter attachment members  4410   a ,  4410   b , and a pair  4416   b  (not shown) of multi-stage filter attachment members  4410   c ,  4410   d , for example attachment ramps as illustrated in  FIGS. 44A and 44B . In some embodiments, the multi-stage filter attachment members  4410   a - 4410   b  provide a replacement cartridge engagement surface. The multi-stage filter attachment members  4410   a ,  4410   b  are generally semi-elliptical (e.g., half circular) members that include a substantially flat portion  4412  extending from an attachment end  4406 . In some embodiments, the members  4410   a ,  4410   b  may have topside geometries that are not rounded (e.g., rectangular, prismatic). The flat portions  4412  generally face the filter body, with the flat portions  4412  of the multi-stage filter attachment members  4410   a  and  4410   c  arranged substantially perpendicular relative to the axis of the filter body, and the flat portions  4412  of the multi-stage filter attachment members  4410   b  and  4410   d  arranged at an angle between perpendicular and parallel relative to the axis of the filter body (e.g., at a 30 degree angle, 45 degree angle, 60 degree angle). The multi-stage filter attachment members  4410   a  and  4410   c  are located relatively axially closer to the filter body than the multi-stage filter attachment members  4410   b  and  4410   d . The multi-stage filter attachment member  4410   a  is arranged axially opposite the multi-stage filter attachment member  4410   c  (not shown). The multi-stage filter attachment member  4410   b  is arranged axially opposite the multi-stage filter attachment member  4410   d.    
         [0141]    In the illustrated example, the filter engagement surface includes the pairs  4416   a  and  4416   b  extending from an outer surface of the filter cap  4400  (e.g., the neck portion) and disposed within 180 degrees of rotation on the outer surface. The pairs  4410   a  and  4410   b  are spaced axially and circumferentially apart from each other with respect to a centerline axis of the filter cartridge and the filter cap  4400  extending in a longitudinal direction. 
         [0142]    The multi-stage filter attachment members  4410   a - 4410   d  form filter engagement surfaces that are non-congruent to the manifold engagement surfaces, e.g., the multi-stage manifold attachment members  356   a ,  356   b . In use, the axially and radially offset relative arrangement of the multi-stage filter attachment members  4410   a - 4410   d  provide surfaces that can engage with the pair of multi-stage manifold attachment members  356   a ,  356   b , illustrated as attachment ramps, on an interior perimeter wall  359  of the distribution manifold  332  of  FIGS. 25, 28 and 33 . The multi-stage filter attachment members  4410   a - 4410   d  can be non-congruent to the manifold engagement surfaces of the multi-stage manifold attachment members  356   a ,  356   b  and yet be suitable for engaging with the manifold engagement surfaces of the multi-stage manifold attachment members  356   a ,  356   b . In some embodiments, the shape and structure of the filter cartridge  4006  and/or the filter cap  4400  can be modified as suitable for the application. For example, in some embodiments the filter cap  4400  can be omitted and the multi-stage filter attachment members  4410   a - 4410   d  can be otherwise connected to the filter cartridge  4006 . 
         [0143]    The filter cap  4400  includes an indicium  4420 . In some embodiments, the indicium  4420  can be a label, sticker, stamp, impression, or any other appropriate indicator that can be visible upon the filter cap  4400  or elsewhere on the filter cartridge  4006  or packaging. The indicium  4420  provides compatibility information that indicates the distribution manifolds  332  and/or appliances to which the filter cartridge  4006  can be engaged or that indicates a replaceable filter cartridge. The indicium  4420  can be an indicium selected from the group consisting of a model number and/or other indicium listed in TABLE 1. 
         [0144]      FIGS. 45A and 45B  are fragmentary perspective and side views of a filter cartridge  4008 , which is another embodiment of the filter cartridge of  FIG. 13  with an expanded view of another example filter cap  4500 . In some embodiments, the filter cap  4500  can be used with the filter cartridge  4008  in place of the filter cap  302 . In some embodiments, some or all of the features of the filter cap  302  not explicitly shown or discussed with respect to the filter cap  4500  may be included in the filter cap  4500  as well. 
         [0145]    In some embodiments, the filter cap  4500  may be used with the filter cartridge  4008  to provide an engagement structure. In some embodiments, the filter cap  4500  may be constructed of a first polymer, such as polypropylene, having a specific quality such as, for example, strength or rigidity. Examples of suitable polymers include metallocene modified polypropylene or polyethylene polymers and copolymers as well as either high or low density polyethylene polymers. In some embodiments, the filter cap  4500  and the filter body  304  may be joined by, for example, an engageable thread or other joining techniques such as adhesives, heat welding, spin welding, ultrasonic welding and any other appropriate means for joining components. In some embodiments, the filter cap  4500  can be integrally formed with the filter body  304  such that the filter cap  4500  is an integral neck portion of the filter body  304 . 
         [0146]    The filter cap  4500  can include a pair of opposed and similarly configured multi-stage filter attachment members  4510   a ,  4510   b , for example attachment ramps as illustrated in  FIGS. 45A and 45B . In some embodiments, the multi-stage filter attachment members  4510   a - 4510   b  provide a replacement cartridge engagement surface. The multi-stage filter attachment members  4510   a ,  4510   b  include a first angled portion  4512   a  adjacent to a first horizontal portion  4514   a , the first horizontal portion  4514   a  facing toward the filter body, a second angled portion  4516   a  adjacent to the first horizontal portion  4514   a , a second horizontal portion  4518   a  facing toward the filter body, and a third angled portion  4519   a  adjacent to the second horizontal portion  4518   a . The multi-stage filter attachment member  4510   b  can include a first angled portion  4512   b , a first horizontal portion  4514   b , a second angled portion  4516   b , a second horizontal portion  4518   b  and a third angled portion  4519   b.    
         [0147]    In the illustrated example, the filter engagement surface includes the multi-stage filter attachment members  4510   a  and  4510   b  extending from an outer surface of the filter cap  4500  (e.g., the neck portion) and disposed generally opposed to each other on the outer surface. The multi-stage filter attachment members  4510   a  and  4510   b  are spaced axially and circumferentially apart from each other with respect to a centerline axis of the filter cartridge  4008  and the filter cap  4500  extending in a longitudinal direction. 
         [0148]    The horizontal portions  4514   a ,  4514   b ,  4518   a , and  4518   b  each include a collection of sprags  4522  oriented toward the filter body. The sprags  4522  form a generally sawtooth pattern along the otherwise generally horizontal portions  4514   a ,  4514   b ,  4518   a , and  4518   b . The sprags  4522  can each extend to a point, such that one, more, or all of the horizontal portions  4514   a ,  4514   b ,  4518   a , and  4518   b  include substantially no continuous, horizontal surface. The multi-stage filter attachment members  4510   a - 4510   b  form filter engagement surfaces that are non-congruent to the manifold engagement surfaces, e.g., the multi-stage manifold attachment members  356   a ,  356   b . In use, the configuration of the multi-stage filter attachment members  4510   a  and  4510   b  provide surfaces that can engage with the pair of multi-stage manifold attachment members  356   a ,  356   b , illustrated as attachment ramps, on an interior perimeter wall  359  of the distribution manifold  332  of  FIGS. 25, 28 and 33 . The tips of the sprags  4522  can slidingly contact multi-stage manifold attachment members  356   a ,  356   b . The multi-stage filter attachment members  4510   a - 4510   b  can be non-congruent to the manifold engagement surfaces of the multi-stage manifold attachment members  356   a ,  356   b  and yet be suitable for engaging with the manifold engagement surfaces of the multi-stage manifold attachment members  356   a ,  356   b . In some embodiments, the shape and structure of the filter cartridge  4008  and/or the filter cap  4500  can be modified as suitable for the application. For example, in some embodiments the filter cap  4500  can be omitted and the multi-stage filter attachment members  4510   a - 4510   b  can be otherwise connected to the filter cartridge  4008 . 
         [0149]    The filter cap  4500  can include a pair of opposed and similarly configured multi-stage filter attachment members  4510   a ,  4510   b , for example attachment ramps as illustrated in  FIGS. 45A and 45B . that are disposed on the neck portion with at least one vent port also located on the neck portion. As seen in the embodiment in  FIG. 45A , two vent ports ( 4530   a  and  4530   b ) are located in the neck portion. The vent ports  4530   a  and  4530   b  are generally radially opposed to each other. The vent ports allow for relief of pressure trapped in the filter cartridge before complete disengagement during the removal of the filter cartridge from the manifold. 
         [0150]    The filter cap  4500  includes an indicium  4520 . In some embodiments, the indicium  4520  can be a label, sticker, stamp, impression, or any other appropriate indicator that can be visible upon the filter cap  4500  or elsewhere on the filter cartridge  4008  or packaging. The indicium  4520  provides compatibility information that indicates the distribution manifolds  332  and/or appliances to which the filter cartridge  4008  can be engaged or that indicates a replaceable filter cartridge. The indicium  4520  can be an indicium selected from the group consisting of a model number and/or other indicium listed in TABLE 1. 
         [0151]      FIGS. 46A and 46B  are fragmentary perspective and side views of a filter cartridge  4010 , which is another embodiment of the filter cartridge of  FIG. 13  with an expanded view of another example filter cap  4600 . In some embodiments, the filter cap  4600  can be used with the filter cartridge  300  in place of the filter cap  4010 . In some embodiments, some or all of the features of the filter cap  302  not explicitly shown or discussed with respect to the filter cap  4600  may be included in the filter cap  4600  as well. 
         [0152]    In some embodiments, the filter cap  4600  may be used with the filter cartridge  4010  to provide an engagement structure. In some embodiments, the filter cap  4600  may be constructed of a first polymer, such as polypropylene, having a specific quality such as, for example, strength or rigidity. Examples of suitable polymers include metallocene modified polypropylene or polyethylene polymers and copolymers as well as either high or low density polyethylene polymers. In some embodiments, the filter cap  4600  and the filter body  304  may be joined by, for example, an engageable thread or other joining techniques such as adhesives, heat welding, spin welding, ultrasonic welding and any other appropriate means for joining components. In some embodiments, the filter cap  4600  can be integrally formed with the filter body  304  such that the filter cap  4600  is an integral neck portion of the filter body  304 . 
         [0153]    The filter cap  4600  can include a pair of opposed and similarly configured multi-stage filter attachment members  4610   a ,  4610   b , for example attachment ramps as illustrated in  FIGS. 46A and 46B . In some embodiments, the multi-stage filter attachment members  4610   a - 4610   b  provide a replacement cartridge engagement surface. The multi-stage filter attachment members  4610   a ,  4610   b  include a first angled portion  4612   a  adjacent to a first horizontal portion  4614   a , the first horizontal portion  4614   a  facing toward the filter body resembling a “hockey stick”. The multi-stage filter attachment member  4610   b  can include a first angled portion  4612  and a first horizontal portion  4614   b.    
         [0154]    In the illustrated example, the filter engagement surface includes the multi-stage filter attachment members  4610   a  and  4610   b  extending from an outer surface of the filter cap  4600  (e.g., the neck portion) and disposed within 180 degrees of rotation on the outer surface. The multi-stage filter attachment members  4610   a  and  4610   b  are spaced axially and circumferentially apart from each other with respect to a centerline axis of the filter cartridge and the filter cap  4600  extending in a longitudinal direction. 
         [0155]    The multi-stage filter attachment members  4610   a - 4610   b  form filter engagement surfaces that are non-congruent to the manifold engagement surfaces, e.g., the multi-stage manifold attachment members  356   a ,  356   b . In use, the configuration of the multi-stage filter attachment members  4610   a  and  4610   b  provide surfaces that can engage with the pair of multi-stage manifold attachment members  356   a ,  356   b , illustrated as attachment ramps, on an interior perimeter wall  359  of the distribution manifold  332  of  FIGS. 25, 28 and 33 . The multi-stage filter attachment members  4610   a - 4610   b  can be non-congruent to the manifold engagement surfaces of the multi-stage manifold attachment members  356   a ,  356   b  and yet be suitable for engaging with the manifold engagement surfaces of the multi-stage manifold attachment members  356   a ,  356   b . In some embodiments, the shape and structure of the filter cartridge  4010  and/or the filter cap  4600  can be modified as suitable for the application. For example, in some embodiments the filter cap  4600  can be omitted and the multi-stage filter attachment members  4610   a - 4610   b  can be otherwise connected to the filter cartridge  4010 . 
         [0156]    The filter cap  4600  can include a pair of opposed and similarly configured multi-stage filter attachment members  4610   a ,  4610   b , for example attachment ramps as illustrated in  FIGS. 46A and 46B  that are disposed on the neck portion with at least one vent port also located on the neck portion. As seen in the embodiment in  FIG. 46A , two vent ports ( 4630   a  and  4630   b ) are located in the neck portion. The vent ports  4630   a  and  4630   b  are generally radially opposed to each other. The vent ports allow for relief of pressure trapped in the filter cartridge before complete disengagement during the removal of the filter cartridge from the manifold. 
         [0157]    The filter cap  4600  includes an indicium  4620 . In some embodiments, the indicium  4620  can be a label, sticker, stamp, impression, or any other appropriate indicator that can be visible upon the filter cap  4600  or elsewhere on the filter cartridge  4010  or packaging. The indicium  4620  provides compatibility information that indicates the distribution manifolds  332  and/or appliances to which the filter cartridge  4010  can be engaged or that indicates a replaceable filter cartridge. The indicium  4620  can be an indicium selected from the group consisting of a model number and/or other indicium listed in TABLE 1. 
         [0158]      FIG. 47  is a flow diagram of an example process  4700  for replacing a filter cartridge. In some implementations, the process  4700  can be used with the filter cartridges  4000 ,  4002 ,  4004 ,  4006 ,  4008 , and/or  4010 , the filter caps  4100 ,  4200 ,  4300 ,  4400 ,  4500 , and/or  4600 , and the distribution manifold  332  of  FIGS. 1-46 . 
         [0159]    At step  4710 , a replaceable filter cartridge is removed from a manifold assembly. The manifold assembly includes a manifold engagement mechanism having a manifold engagement surface with a first horizontal portion, a second horizontal portion, and an angled portion disposed between and joining the first horizontal portion to the second horizontal portion. For example, the filter cartridge  300  can be removed from the distribution manifold  332 , which includes the attachment members  356   a ,  356   b.    
         [0160]    At step  4720 , a replacement filter cartridge is inserted into the manifold assembly. The replacement filter cartridge includes a replacement cartridge engagement mechanism having a replacement cartridge engagement surface that is non-congruent to the manifold engagement surface. For example, the filter cap  4100 ,  4200 ,  4300 ,  4400 ,  4500 , or  4600  include corresponding multi-stage filter attachment members that are configured and arranged to provide a replacement cartridge engagement mechanism that is non-congruent to the manifold members  356   a ,  356   b.    
         [0161]    At  4730 , the replacement filter cartridge is turned to engage the filter engagement surface with the manifold engagement surface. In some implementations, the process  4700  can also include sliding the filter engagement surface against the second horizontal portion, sliding the filter engagement surface against the angled portion after sliding the filter engagement surface against the second horizontal portion, and sliding the filter engagement surface against the first horizontal portion after sliding the filter engagement surface against the angled portion. For example, any of the filter cartridges  4000 ,  4002 ,  4004 ,  4006 ,  4008 , or  4010 , configured with any of the filter caps  4100 ,  4200 ,  4300 ,  4400 ,  4500 , or  4600 , can be operatively connected to the distribution manifold  332  to form a filtration system similar to the filtration system  366 , as discussed previously in the descriptions of  FIGS. 31, 32 and 33 . 
         [0162]    Although a few implementations have been described in detail above, other modifications are possible. For example, in the logic flows depicted in the figures, steps may be provided, or steps may be eliminated, from the described flows, and other components may be added to, or removed from, the described systems. Components and features from different filter cartridges may be combined or modified as suitable for a particular application. For example, with respect to the filter cartridge  4002 , the filter attachment member  4210   a  can be omitted and replaced with the filter attachment member  4310   b  positioned substantially opposite the filter attachment member  4210   b . Accordingly, other implementations are within the scope of the following claims.