Abstract:
A crossflow filtration system including at least one quick dry change crossflow filtration cartridge designed to rotatably interface with a manifold assembly. The quick dry change crossflow filtration cartridge can comprise a membrane element, for example an ultrafiltration membrane, microfiltration membrane, nanofiltration membrane or reverse osmosis membrane element enclosed within a housing. The quick dry change cartridge includes an inlet stream, a permeate stream and a concentrate stream. The manifold assembly includes three similar flow paths; an inlet stream, a permeate stream and a concentrate stream. When engaged, the cartridge and manifold assembly define continuous inlet flow paths, permeate flow paths and concentrate flow paths that connect across the interface. Thus, all of the connections to the water filtration system can be made onto the manifold, and the resulting connected system is compact and easy to connect.

Description:
RELATED APPLICATIONS AND PRIORITY CLAIM 
       [0001]    This application is a continuation of U.S. application Ser. No. 10/838,140 filed May 3, 2004, now pending, which claims priority to U.S. Provisional Application No. 60/467,663, filed May 2, 2003 entitled, “RESIDENTIAL REVERSE OSMOSIS SYSTEM WITH QUICK DRY CHANGE ELEMENTS,” which is hereby incorporated by reference in its entirety. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates generally to the field of water filtrations systems. More specifically, the present invention relates to crossflow filtration systems utilizing a crossflow filtration element capable of being added and replaced by a quick connect attachment. 
       BACKGROUND OF THE INVENTION 
       [0003]    Water filtration systems designed for use in the home are well known. Due to increasing concerns with regard to water quality, be it supplied by a well or a municipality, the popularity of such systems has increased markedly. Some water filtration systems incorporate reverse osmosis filtration. 
         [0004]    Typical reverse osmosis systems include a reverse osmosis membrane assembly, a pressure tank, a control element, a purified water faucet and a tubing/piping assembly defining the various flow paths. In general, an inlet water source is supplied to the membrane assembly where it is separated into a purified water stream (commonly referred to as permeate) and a concentrated waste stream (commonly referred to as concentrate). The permeate may flow to a pressure tank where it can subsequently be accessed through the pure water faucet. The concentrate is typically piped directly to drain. The control element working in conjunction with a series of valves in the tubing/piping assembly and the pure water faucet generally operates the system and may include various monitoring sensors, for example conductivity/resistivity and flow sensors to insure the system is functioning properly. 
       SUMMARY OF THE INVENTION 
       [0005]    The present invention comprises a crossflow filtration system, for example a residential crossflow filtration system, including at least one quick dry change crossflow filtration cartridge designed to rotatably interface with a manifold assembly. The quick dry change crossflow filtration cartridge can comprise a membrane element, for example an ultrafiltration membrane, microfiltration membrane, nanofiltration membrane or reverse osmosis membrane element enclosed within a housing. A rotatably engaging cartridge fastener has two mated elements with one element attached to the housing of the filtration cartridge and the mated second element of the fastener attached to a docking port on the manifold. The housing includes a housing cap having the first fastener element for rotatably connecting to the mated second fastening element at the docking port on the manifold assembly. The fastener can comprise a variety of designs of mated elements, for example, angled tabs, grooves, helical threads, multi-stage engagement members using threads and/or tabs and combinations thereof. Similarly, the mated second fastening element can comprise corresponding mated elements, such as angled tabs, grooves, ramps, multi-stage engagement members or combinations thereof, for interfacing with the first fastener element. The port on the manifold can also comprise a variety of capture mechanisms such that the cartridge fastener does not disengage unintentionally. Examples of appropriate rotatably engaging cartridge fasteners contemplated for use with the water purification systems described herein include, for example, those disclosed in U.S. patent application Ser. Nos. 09/618,686, 10/196,340, 10/202,290 and 10/406,637, all of which are hereby incorporated by reference in their entirety. 
         [0006]    The quick dry change cartridge includes three flow paths within the housing and a crossflow filtration media element. The three flow paths include an inlet stream, a permeate stream and a concentrate stream. The manifold assembly includes three similar flow paths; an inlet stream, a permeate stream and a concentrate stream. When engaged, the cartridge and manifold assembly define continuous inlet flow paths, permeate flow paths and concentrate flow paths that connect across the interface. Thus, all of the connections to the water filtration system can be made onto the manifold, and the resulting connected system is compact and easy to connect. In contrast, reverse osmosis designs with a separate condensate drain are represented by U.S. Pat. Nos. 3,746,640, 4,391,712, 4,876,002, 5,122,265, 5,435,909, 5,527,450, 5,580,444 and 6,436,282, all of which are hereby incorporated by reference in their entirety. 
         [0007]    When the filtering capacity of the crossflow filtration media element is consumed, the unitary construction of the cartridge allows for quick and easy replacement with a new cartridge containing a new crossflow filtration media element. As there is no disassembly of the cartridge filter, the replacement process can be accomplished without water spillage. In addition, the time required is only that necessary to rotatably remove a spent cartridge and rotatably install a new cartridge. Generally, disassembly and reassembly of the housing and filter cartridge can be performed by hand without any tool, although a tool can be used if desired. In certain embodiments, the filtering characteristics of the crossflow filtration system can be adjustably varied by replacing a cartridge filter having a first media with a new cartridge filter having a second type of filtration media. In addition, operational performance of the crossflow filtration system can be adjusted, which may be desired due to changes in the feedwater chemistry, simply by replacing cartridge filters wherein the cartridge filter includes a specific orifice, thereby controlling overall recovery of the crossflow filtration system. Adjustment can be performed by varying the backpressure on the concentrate stream, for example, by using a flow restrictor such as an orifice or valve. 
         [0008]    In a first aspect, the invention pertains to a crossflow filtration system comprising a crossflow cartridge filter and a manifold. The crossflow cartridge filter can comprise a housing, an enclosed crossflow filtration media and a first fastener element defining three filter connections that are respectively in fluid communication with a filter feed channel, a filter permeate channel and a filter concentrate channel passing within the cartridge filter. The manifold can comprise a second fastener element mated with the first fastener element, the manifold having three manifold flow channels that connect respectively to three manifold connections on the second fastener element. The three manifold connections connect on a one-to-one basis with the three filter connections when the first fastener element is engaged with the second fastener element. 
         [0009]    In another aspect, the invention pertains to a crossflow filtration filter comprising a filter housing, a crossflow filtration element and a filter cap. The crossflow filtration element can comprise a crossflow filtration media such as a microfiltration membrane, an ultrafiltration membrane, a nanofiltration membrane or a reverse osmosis membrane. The filter cap can include channels for directing and distributing a feed water stream, a concentrate stream and a permeate stream. The filter cap can further comprise engagement members allowing for interconnection, for example rotatable engagement, with a filter manifold. 
         [0010]    In another aspect, the invention pertains to a crossflow filtration manifold comprising a manifold body and a manifold connection. The manifold body and the manifold connection can define a feed flow channel, a permeate flow channel and the a concentrate flow channel. The manifold connection can include an engagement member for allowing rotatable connection with a cartridge filter. The crossflow filtration manifold can include a flow restriction, such as a valve or orifice, in the concentrate flow channel to backpressure and control the water recovery for a crossflow filtration cartridge. The crossflow filtration manifold can include a biased closed valve in the feed flow channel to prevent water spillage when the manifold is not engaged with a cartridge filter. The crossflow filtration manifold can include a check valve in the permeate flow channel to prevent backward flow of filtered water through the manifold. 
         [0011]    In another aspect, the invention pertains to a method for forming a water filtration system with a crossflow filter. The method comprises connecting the crossflow filter to a manifold such a feed flow circuit, a permeate flow circuit and a concentrate flow circuit are formed and isolated by a crossflow filtration media. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0012]      FIG. 1  is a side view of a crossflow filtration assembly. 
           [0013]      FIG. 2  is an exploded, perspective view of a crossflow cartridge filter. 
           [0014]      FIG. 3  is a sectional, side view of a filter housing. 
           [0015]      FIG. 4  is a sectional, side view of a crossflow filtration element. 
           [0016]      FIG. 5  is a sectional, side view of a filter dam. 
           [0017]      FIG. 6  is a sectional, side view of a filter cap. 
           [0018]      FIG. 7  is a top, end view of the filter cap of  FIG. 6 . 
           [0019]      FIG. 8  is a bottom, end view of the filter cap of  FIG. 6 . 
           [0020]      FIG. 9  is a sectional, side view of a crossflow cartridge filter. 
           [0021]      FIG. 10  is an exploded, perspective view of a manifold assembly. 
           [0022]      FIG. 11  is a perspective view of a distributing member. 
           [0023]      FIG. 12  is a side view of a connecting member. 
           [0024]      FIG. 13  is a perspective view of the connecting member of  FIG. 12 . 
           [0025]      FIG. 14  is a sectional, side view of the connecting member of  FIG. 12 . 
           [0026]      FIG. 15  is a perspective, end view of the manifold assembly of  FIG. 10 . 
           [0027]      FIG. 16  is a side view of the manifold assembly of  FIG. 10 . 
           [0028]      FIG. 17  is a sectional, side view of the manifold assembly of  FIG. 10  take along line A-A of  FIG. 16 . 
           [0029]      FIG. 18  is a sectional, side view of the crossflow filtration assembly of  FIG. 1 . 
           [0030]      FIG. 19  is a schematic diagram of a water treatment system including a crossflow filtration assembly. 
           [0031]      FIG. 20  is an exploded, perspective view of an embodiment of a water treatment system. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0032]    As illustrated in  FIG. 1 , an embodiment of a crossflow filtration assembly  90  of the present invention comprises a manifold assembly  92  and at least one crossflow cartridge filter  94 . As depicted in  FIG. 1 , an embodiment of the crossflow filtration assembly  90  includes a supply tube  96 , a concentrate tube  98  and a permeate tube  100 . 
         [0033]    The crossflow cartridge filter  94  is more clearly illustrated in  FIG. 2 . Generally, crossflow cartridge filter  94  comprises a filter housing  108 , a crossflow filtration element  110 , a flow director  112  and a filter cap  114 . Filter housing  108 , flow director  112  and filter cap  114  are constructed of suitable polymers for example, polypropylene or polyethylene. Crossflow cartridge filter  94  is constructed so as to be fixedly sealed and closed such that when replacement is necessary, the entire cartridge is replaced as opposed to replacing individual cartridge components such as crossflow filtration element  110 . This system has a single filter element. Different systems can incorporate different numbers of filter elements, such as two, three, four or more of the same or different types, as well as holding tanks. One particular design with multistage filtration is described further below. 
         [0034]    As is shown in  FIGS. 2 and 3 , filter housing  108  comprises a molded polymeric structure having an open end  116  and a closed end  118 . In some embodiments, filter housing  108  comprises a gripping element  120  as shown in  FIG. 2 , for example a projecting surface, on closed end  118 . Open end  116  can include an internal circumferential notch  122  to promote the interconnection and assembly of crossflow cartridge filter  94 . Filter housing  108  generally can have a smooth inner wall  124  and can include an internal projection  126  protruding upward from the internal surface of closed end  118 , as shown in the cross-sectional view of  FIG. 3 . Internal projection  126  can comprise a tapered guide surface  128  for use during assembly of crossflow cartridge filter  94 . 
         [0035]    As depicted in  FIG. 4 , crossflow filtration element  110  can comprise a spirally wound design referred to as a spiral wound element, in which a crossflow filter membrane media  130  is glued to and wrapped around an interior permeate tube  132  having one or a plurality of tube bores  134 . Permeate tube  132  has a cylindrical configuration including an open tube end  136 , a closed end  138  and a tube recess  140 . At open tube end  136 , permeate tube  132  includes a weld channel  142 . A tube recess  140  can be dimensioned to accommodate insertion of internal projection  126  of filter housing  108  ( FIG. 3 ) during assembly. For purposes of clarity, it is to be understood that the tube bores  134  are located between open end  136  and closed end  138 . 
         [0036]    In some embodiments, the crossflow filter membrane media  130  can comprise two sheets of membrane, for example sheets of reverse osmosis, nanofiltration, ultrafiltration or microfiltration membrane, sandwiched over a spacer material. The two sheets of membrane can be glued around three sides with a fourth side being open and glued to the permeate tube  132  allowing water to be filtered through the individual flat sheets, into the spacer material, through the tube bores  134  and finally into permeate tube  132 . The crossflow filter membrane media  130  can be manufactured of polymers such as cellulose acetate, polyamide and polysulfone. Suitable crossflow filter membrane media  130  is manufactured and sold by companies such as GE Water Technologies (formerly Osmonics, Inc.), Dow Liquid Separations/FilmTec, Hydranautics and Koch Membrane Systems, among others. In alternative embodiments, the crossflow filter membrane  130  can comprise tubular elements and/or sheets of membrane. 
         [0037]    Flow director  112  depicted in  FIGS. 2 and 5 , comprises a media end  144 , a cap end  146 , a central throughbore  148  and a plurality of perimeter throughbores  150 . Central throughbore  148  and perimeter throughbores  150  are isolated by interior wall  152 . Media end  144  has a circular configuration with a diameter slightly greater than open end  136  of interior permeate tube  132  such that a circumferential projecting lip  154  projects around the perimeter of crossflow filtration element  110 . Central throughbore  148  interfaces with media end  144  at a projecting sealing surface  156 . Projecting sealing surface  156  is dimensioned for insertion into open end  136  and includes a flanged sealing surface  158  having a circumferential weld energy director  160  corresponding to weld channel  142  of interior permeate tube  132 . Cap end  146  is defined by end surfaces of an exterior wall  162 , interior wall  152  and a plurality of support ribs  164  shown in  FIG. 2 . 
         [0038]    Filter cap  114  depicted in  FIGS. 2 ,  6 ,  7  and  8  comprises a manifold engagement end  166 , a cartridge sealing end  168 , a plurality of supply throughbores  170 , a central permeate throughbore  172  and a concentrate bore  174 . Permeate throughbore  172  is dimensioned to accommodate the insertion of interior wall  152  of filter damn  112 . Concentrate bore  174  is defined by an outlet portion  174   a  and an inlet portion  174   b . Outlet portion  174   a  can comprise a precision drilled or molded bore restriction. Alternatively, an orifice, for example a drilled orifice with an orifice filter, can be mounted within the outlet portion  174   a  to provide a desired cross-sectional opening with the outlet portion  174   a . An interconnecting cavity  176  is exposed at manifold engagement end  166  and includes a plurality of notches  178  along a perimeter wall  180  of interconnecting cavity  176 . Also within interconnecting cavity  176  is a pair of arcuate interface ramps  182   a ,  182   b . A sealing cavity  184  is exposed at cartridge sealing end  168  and is dimensioned to accommodate flow director  112 . Filter cap  114  includes an exterior surface  186  including a fastening element for connecting with a mated fastening element on the assembly manifold  102 . The fastening element can comprise a pair of circumferential ramps  188   a ,  188   b , also depicted in  FIG. 2 . For interfacing with filter housing  108 , the filter cap comprises a circumferential insertion lip  190 , a circumferential recess  192  and a circumferential flange  194 . While in this embodiment filter damn  112  and filter cap  114  are separate elements, these elements can be formed as a single integral unit. 
         [0039]    A sectional view of an assembled crossflow cartridge filter  94  is illustrated in  FIG. 9 . Flow director  112  is positioned with respect to crossflow filtration element  110  such that the projecting sealing surface  156  is slidingly inserted into the open tube end  136 . When properly positioned, weld energy director  160  at least partially resides within weld channel  142 . Using a suitable welding process, for example spin welding or ultrasonic welding, the weld energy director  160  and weld channel  142  can be attached. At the same time, projecting lip  154  can be sealed by friction bonding and/or the use of a suitable adhesive about the outside of crossflow filtration element  110 . Crossflow filtration element  110  is directed into the open end  116  of filter housing  108  such that the internal projection  126  is inserted into the tube recess  140 . Filter cap  114  is positioned and directed such that the cartridge sealing end  168  is proximal the cap end  146  and the open end  116 , causing slidable insertion of the interior wall  152  into the central permeate throughbore  172 . Simultaneously, the circumferential insertion lip  190 , circumferential recess  192  and the circumferential flange  194  contact the filter housing  108 , for example at internal circumferential notch  122 . Using a suitable welding process, for example spin welding or ultrasonic welding, filter cap  114  is welded to filter housing  108  to form the completed crossflow cartridge filter  94 . Suitable adhesive sealing methods can also be employed during the assembly of crossflow cartridge filter  94  in addition or as an alternative to a welding process. 
         [0040]    When assembled, crossflow cartridge filter  94  defines three distinct flow circuits: a feed water flow circuit, a permeate flow circuit and a concentrate flow circuit. Incoming feed water enters the feed water flow circuit through the supply throughbores  170  such that the feed water flows through the filter cap  114 . The feed water then passes through the perimeter throughbores  150  on the flow director  112  and into crossflow filtration element  110 . As the feed water passes across the crossflow filter membrane media  130 , purified water enters the permeate flow circuit through the tube bores  134  in the interior permeate tube  132 . The permeate flow circuit is defined by the interior permeate tube  132 , the central throughbore  148  on the flow director  112  and the central permeate throughbore  172  on filter dam  114 . Any water that passes across crossflow filtration element  110  without entering the permeate flow circuit flows out the bottom of the crossflow filtration element  110  and into the concentrate flow circuit. The concentrate flow circuit is first defined by the gap between the exterior of the crossflow filtration element  110  and the smooth inner wall  124 . The concentrate fluid circuit is further defined by the concentrate bore  174  whereby concentrate is collected and distributed out of the crossflow cartridge filter  94 . 
         [0041]    As illustrated in  FIG. 10 , an embodiment of manifold assembly  92  can comprise a distributing member  196 , a connecting member  198 , a spring loaded valve  200 , a pair of first O-ring seals  202   a ,  202   b  and a pair of second O-ring seals  204   a ,  204   b.    
         [0042]    Distributing member  196  is illustrated in  FIGS. 10 and 11 . Distributing member  196  has a distribution end  206  and a connection end  208 . Extending between the distribution end  206  and the connection end  208  are a distribution feed throughbore  210 , a distribution concentrate throughbore  212  and a distribution permeate throughbore  214 . Located on connection end  208  is a pair of attachment projections  216 . Connection end  208  further includes a connecting surface  218  and a perimeter distribution wall  220 . Perimeter distribution wall  220  includes a filter receiving means, shown as a pair of tabs  222   a ,  222   b  and a pair of sloped members  224   a ,  224   b.    
         [0043]    Connecting member  198 , as shown in  FIGS. 12 ,  13  and  14 , includes a manifold attachment end  226  and a filter attachment end  228 . Manifold attachment end  226  includes a feed inlet bore  230 , a permeate outlet bore  232  and a concentrate outlet bore  234 . Manifold attachment end  226  further includes a pair of manifold attachment members  236  for interconnection of the connecting member  198  to the distributing member  196 . Filter attachment end  228  includes a connector projection  238  with a permeate throughbore  240  in fluid connection with the permeate outlet bore  232 . Filter attachment end  228  further includes a feed outlet bore  241 . Connector projection  238  has a pair of circumferential projection grooves  242   a ,  242   b  for receiving the O-ring seals  202   a ,  202   b . Connector projection  238  has a diameter such that connector projection  238  inserts into the central permeate throughbore  172 . Connecting member  198  includes a pair of circumferential body grooves  246   a ,  246   b  for receiving O-ring seals  204   a ,  204   b . Located between circumferential body grooves  246   a ,  246   b  is a concentrate inlet bore  250 . 
         [0044]    Manifold assembly  92  is generally constructed as shown in  FIGS. 10 ,  15 ,  16  and  17 . Distributing member  196  is oriented such that the connection end  208  is facing the manifold attachment end of the connecting member  198 . The spring loaded valve  200  is positioned such that it is captured and resides on a valve seat  251  within the distribution feed throughbore  210  and the feed inlet bore  230  as the distributing member  196  and the connecting member  198  are coupled. As the distributing member  196  and the connecting member  198  come into contact, the manifold attachment members  236  slide over the attachment projections  216 . Once the connection end  208  and the manifold attachment end  226  are in physical contact, the distributing member  196  and the connecting member  198  are joined with a suitable joining technique, for example sonic welding and/or adhesive bonding. When the distributing member  196  and the connecting member  198  are operably joined, a continuous manifold feed channel  252  is defined by the distribution feed throughbore  210 , the feed inlet bore  230  and the feed outlet bore  241 ; a continuous manifold concentrate channel  254  is defined by the concentrate inlet bore  250 , the concentrate outlet bore  234  and the distribution concentrate throughbore  212 ; and a continuous manifold permeate channel  256  is defined by the permeate throughbore  240 , the permeate outlet bore  232  and the distribution permeate throughbore  214 . In alternative embodiments, the distribution member and the connection member can be formed as a single integral unit. 
         [0045]    Following the assembly and plumbing of manifold assembly  92 , the crossflow cartridge filter  94  is sealingly attached to the manifold assembly  92  as shown in  FIG. 18 . In one embodiment, the crossflow cartridge filter  94  is rotatably coupled to the manifold assembly  92 . Crossflow cartridge filter  94  is positioned and aligned such that central throughbore  148  is in alignment with and proximate to connector projection  238 . Connector projection  238  is slidably inserted into central throughbore  148  such that circumferential ramps  188   a ,  188   b  physically contact tabs  222   a ,  222   b . Crossflow cartridge filter  94  is rotatably biased such that circumferential ramp  188   a  is captured between tab  222   a  and sloped member  224   a  while circumferential ramp  188   b  is simultaneously captured between tab  222   b  and sloped member  224   b . Further rotation of crossflow cartridge filter  94  causes approximation of the crossflow cartridge filter  94  and the manifold assembly  92  such that connector projection  238  is fully inserted into central throughbore  148 . Ultimately, the first pair of O-ring seals  202   a ,  202   b  create a fluid tight seal between connector projection  238  and central throughbore  148  to prevent water leakage. As connector projection  238  is fully inserted into central throughbore  148 , either arcuate interface ramp  182   a  or  182   b  contacts the spring loaded valve  200 . As crossflow cartridge filter  94  is rotated, arcuate interface ramp  182   a  or  182   b  causes spring loaded valve  200  to compress such that the spring loaded valve  200  is lifted from the valve seat  251 . As spring loaded valve  200  is lifted from valve seat  251 , feed water can begin to flow into the manifold assembly  92 . 
         [0046]    Once the crossflow filtration assembly  90  is assembled, feed water can begin to flow into the manifold assembly  92  through the supply tube  96 . The feed water flows past the spring loaded valve  200  within the manifold feed channel  252  and enters the crossflow cartridge filter  94  through the supply throughbores  170 . The feed water enters the crossflow filtration element  110  such that some water is directed through the membrane media  130 . As the water travels the length of crossflow filtration element  110 , the water volume decreases while the number of contaminants present within the water flow increases. At the end of the crossflow filtration element  100  nearest the closed end  118 , the concentrated feed water flows from the crossflow filtration element  110  to form a concentrate stream having a high concentration of contaminants. At the same time, purified water that has passed through the membrane media  130  is collected within the interior permeate tube  132  to form a permeate stream, essentially free of contaminants. 
         [0047]    The concentrate stream flows between the crossflow filtration element  110  and the inner wall  124 . By directing the concentrate stream in the gap between the crossflow filtration element  110  and the inner wall  124 , the potential for deadspots or regions of stagnant water is eliminated. By eliminating deadspots, the potential for biological growth and contamination within the crossflow filtration element  110  is minimized. The concentrate stream enters the circumferential concentrate bore  174  whereby the concentrate stream flows into the concentrate inlet bore  250 . O-ring seals  204   a ,  204   b  prevent the concentrate stream from contaminating either the feed stream or the permeate stream. From the concentrate inlet bore  250 , the concentrate stream is directed through the manifold concentrate channel  254  and to drain through the concentrate tube  98 . At various points, either within the manifold assembly  92  or the crossflow cartridge filter  94 , a restriction can be placed within the concentrate flow stream to backpressure the concentrate stream such that the volume of the permeate stream can be increased or decreased. For example, this restriction can take the form of a fixed or adjustable orifice located in first portion  174   a , or a valve within the manifold assembly  92 . The restriction is typically adjusted based on the water quality of the feed supply. For a high quality feed supply, the volume of the permeate stream can be increased as opposed to a feed water supply of a lower quality. For example, where the feed supply is of a poor quality, the recovery can be set at 50% wherein half of the incoming feed supply is filtered to become the permeate stream. Where the feed supply is of a high quality, the recovery can be set as high at 90% wherein the flow rate of the permeate stream is 90% of the flow rate of the feed supply. 
         [0048]    The purified permeate stream is collected within the interior permeate tube  132  whereby it flows through the central throughbore  148  and into the permeate throughbore  240 . Once in the permeate throughbore  240 , the permeate stream flows through the manifold permeate channel  256  whereby the permeate stream is directed to points of use by the permeate tube  100 . In an embodiment, permeate tube  100  may deliver the permeate stream to a pressurized permeate tank for subsequent distribution to points of use. In the case of a pressurized permeate tank, the manifold assembly  92  could include a checkvalve to prevent any backflow of permeate from the pressurized permeate tank when the crossflow cartridge filter  94  is removed from the manifold assembly  92 . 
         [0049]    As illustrated in  FIG. 19 , crossflow filtration assembly  90  can be used in conjunction with a pretreatment filter  300  and a posttreatment filter  302  to form a water treatment system  304 . As illustrated, water treatment system  304  can further comprise a feed inlet  306 , a pretreatment manifold  308 , a shutoff valve  310 , a checkvalve  312 , a flow restrictor  314 , a drain  316 , a permeate outlet  317 , a storage tank  318 , a posttreatment manifold  320 , distribution stream  321  and a distribution control  322 . The water treatment system  304  can be selectively configured, through the use of various pretreatment filters  300  and posttreatment filters  302  to provide a desired filtered water quality based upon the available feed water quality. For instance, pretreatment filter  300  can include a filter media to remove particulate matter, chlorine, chloramines, organics or hardness. Likewise, posttreatment filter  302  can include filter media to remove any remaining dissolved solids, chlorine, organics and biological material or to removed undesirable taste and/or odor associated with water stored in storage tank  318 . Furthermore, pretreatment filter  308  can be configured to increase the permeate recovery of the crossflow filtration assembly  90  such that the flow rate to drain  316  is reduced. The flow restrictor can be used to alter the performance of the filtration medium. In particular, a more restricting flow restrictor can be used to lower the ratio of concentrate flow to permeate flow, while a less restricting flow restrictor increases the ratio of concentrate flow to permeate flow. 
         [0050]    In one alternative embodiment of water treatment system  304  illustrated in  FIG. 20 , crossflow filtration assembly  90 , pretreatment filter  300 , posttreatment filter  302 , feed inlet  306 , pretreatment manifold  308 , shutoff valve  310 , checkvalve  312 , flow restrictor  314 , drain  316 , posttreatment manifold  320  and distribution stream  321  can be incorporated into a unitary manifold assembly  330 . Both pretreatment filter  300  and pretreatment manifold  308  as well as posttreatment filter  302  and posttreatment manifold  320  can make use of quick connect filter and manifold assembly designs having one inlet and one outlet, for example as disclosed in U.S. patent application Ser. Nos. 09/618,686, 10/196,340, 10/202,290 and 10/406,637. 
         [0051]    Although various embodiments of the present invention have been disclosed here for purposes of illustration, it should be understood that a variety of changes, modifications and substitutions might be incorporated without departing from either the spirit or scope of the present invention.