Abstract:
A filtering system for a dishwashing appliance that can remove fine particles from the wash and rinse fluids is provided. A filter cartridge is provided with different filter media for the removal of different particulate sizes depending upon e.g., the cycle or stage of the cleaning process and/or anticipated particle size. The filter cartridge is positioned upstream from the pump inlet. A mechanism for diverting flow between filter media is provided. In certain embodiments, the filter cartridge can be removable for servicing.

Description:
FIELD OF THE INVENTION 
       [0001]    The subject matter of the present disclosure relates generally to filtration of the wash and/or rinse fluids in a dishwashing appliance. 
       BACKGROUND OF THE INVENTION 
       [0002]    During wash and rinse cycles, dishwashers typically circulate a fluid through a wash chamber over articles such as pots, pans, silverware, and other cooking utensils. The fluid can be e.g., various combinations of water and detergent during the wash cycle or water (which may include additives) during the rinse cycle. Typically the fluid is recirculated during a given cycle using a pump. Fluid is collected at or near the bottom of the wash chamber and pumped back into the chamber through e.g., nozzles in the spray arms and other openings that direct the fluid against the articles to be cleaned or rinsed. Fluids used in e.g., the wash or rinse cycles may be heated. For example, hot water may be supplied to the dishwasher and/or the dishwasher may include one or more heat sources (e.g., electrically-resistant heating elements) for heating fluids used in wash or rinse cycle and for providing heat during a drying cycle. 
         [0003]    Depending upon the level of soil upon the articles, fluids used during wash and rinse cycles will become contaminated with soils in the form of debris or particles that are carried with the fluid. In order to protect the pump and recirculate the fluid through the wash chamber, it is beneficial to filter the fluid so that relatively clean fluid is applied to the articles in the wash chamber and materials are removed or reduced from the fluid supplied to the pump. 
         [0004]    For mechanical filtration, the selectivity of the filter to remove soil particles of different sizes is typically determined by providing fluid paths (such as pores or apertures) through a filter media that are smaller than the particles for which filtration is desired. Particles having a dimension larger than the width of the fluid paths will be trapped or prevented from passing through the filter while particles smaller than the width of the fluid path will generally pass through. Some particle sizes and/or types may be not harmful to the pump or spray assemblies and, therefore, can be allowed to pass into the pump inlet. However, while some smaller particles may not be harmful to the pump, leaving such particles in the wash or rinse fluid may not be acceptable as these particles may become deposited on the articles being washed/rinsed and thereby affect the user&#39;s perception of the cleanliness and/or appearance. 
         [0005]    While larger particles can generally be readily removed from the fluid circulated through the wash chamber, challenges are presented in removing smaller particles—particularly as the particle size targeted for removal decreases. For example, if a dishwashing appliance is provided with a fine particle filter—such as one for removing particles 200 microns or larger—the filter can be prone to clogging particularly during the early stages of the cleaning process. During a pre-wash cycle or early stage of a wash cycle, a greater amount of larger food particles may be present on the articles placed in the wash chamber. A fine particle filter—such as one for removing particles 200 microns are larger—may become substantially clogged. 
         [0006]    To unclog the filter, a conventional approach has been to drain the dirty fluid from the wash chamber to remove the particles clogging the filter. New—i.e. clean fluid—is then reintroduced for cycling again. Depending on the level of soil still present on the articles, yet another cycle of draining and refilling may have to be repeated. Unfortunately, this run, drain, and refill approach for unclogging a filter is inefficient as it requires the use of additional fluid (i.e. water) and, when the fluid is heated, additional energy is consumed as the fluid is drained and the new water is reheated. Of course, a filter media can be selected that only captures larger particles so that it clogs less, such as e.g., 0.30″ or larger, but this comes at the expense of losing the ability to remove smaller particles from the fluid and an associated effect on the resulting cleanliness of the articles. 
         [0007]    Another challenge with filtration of the wash fluid is servicing of the filter and, more particularly, the filter media. Sometimes, for example, food particles can become lodged in the filter requiring that the filter be removed and either manually cleaned or replaced. Certain conventional dishwashing appliances do not have a filter that is readily accessible to the user and/or otherwise readily cleanable or serviceable. 
         [0008]    Accordingly, a dishwasher appliance having filtering system for the removal of particles from the wash fluid would be useful. More particularly, a filtering system that can remove both large and fine particles (e.g., 50 to 100 micron or larger) without repeated draining and refilling to unclog the filter would be particularly beneficial. Such a filtering system using a filter that can also be readily accessed and serviced would also be useful. 
       BRIEF DESCRIPTION OF THE INVENTION 
       [0009]    The present invention provides a filtering system for a dishwashing appliance that can remove fine particles from the wash and rinse fluids. A filter cartridge is provided with different filter media for the removal of different particulate sizes depending upon e.g., the cycle or stage of the cleaning process and/or anticipated particle size. The filter cartridge is positioned upstream from the pump inlet. A mechanism for diverting flow between filter media is provided. In certain embodiments, the filter cartridge can be removable for servicing. Additional aspects and advantages of the invention will be set forth in part in the following description, or may be apparent from the description, or may be learned through practice of the invention. 
         [0010]    In one exemplary embodiment, the present invention provides a dishwashing appliance that includes a wash chamber having a sump portion; at least one spray arm assembly for providing fluid onto articles placed in the wash chamber; a pump in fluid communication with the spray arm assembly, the pump having a pump inlet; and a filter system positioned at the sump portion of the wash chamber. The filter system is in fluid communication with, and upstream from, the pump inlet. The filter system includes a removable filter cartridge having a plurality of filter media positioned about the filter cartridge, each of the filter media configured for removing different sized particulates than the other filter media; a plurality of fluid channels, each fluid channel having a fluid inlet positioned to receive filtered fluid from one of the plurality of filter media, and a fluid outlet positioned downstream of the fluid inlet; and a diverter mechanism positioned downstream of the filter cartridge and upstream of the pump inlet, the diverter mechanism configured to selectively place any one of the fluid outlets of the fluid channels in fluid communication with the pump inlet. 
         [0011]    In another exemplary embodiment, the present invention provides a dishwashing appliance that includes a wash chamber having a sump portion. The sump portion includes a filter receptacle having a plurality of openings for the egress of filter fluid. A pump is provided for circulating fluid through the wash chamber, the pump having a pump inlet whereby the pump may receive filtered fluid from the filter receptacle. A filter cartridge is removably received into the filter receptacle. The filter cartridge defines a cylindrically-shaped wall surrounding an internal cavity and defines axial and circumferential directions. The cylindrically-shaped wall includes a plurality of filter media positioned proximate to each other along the circumferential direction. Each of the filter media is configured for removing different sized particulates than the other filter media. Each one of filter media is positioned adjacent to one of the openings of the filter receptacle. A diverter mechanism is positioned downstream of the filter cartridge and upstream of the pump inlet. The diverter mechanism is configured to selectively place any one of the openings of the filter receptacle in fluid communication with the pump inlet. 
         [0012]    These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0013]    A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which: 
           [0014]      FIG. 1  provides a front view of an exemplary dishwashing appliance of the present invention. 
           [0015]      FIG. 2  provides a cross-sectional side view of the exemplary dishwashing appliance of  FIG. 1  showing components of a wash chamber. 
           [0016]      FIG. 3  is a front perspective view of the floor of wash chamber from  FIGS. 1 and 2 . 
           [0017]      FIGS. 4 ,  5 , and  6  provide schematic views of an exemplary diverter mechanism of the present invention. 
           [0018]      FIG. 7  provides an exploded view an exemplary filter receptacle and filter of the present invention. 
           [0019]      FIG. 8  is a perspective and partial cross-sectional view of the exemplary filter receptacle of  FIG. 7 . 
           [0020]      FIG. 9  is another perspective and partial cross-sectional view of the exemplary filter receptacle of  FIG. 7 . 
           [0021]      FIG. 10  provides a cross-sectional view from the top of the exemplary filter receptacle of  FIG. 7 . 
           [0022]      FIG. 11  is another cross-sectional view of the exemplary filter receptacle of  FIG. 7 . 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0023]    Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents. 
         [0024]    As used herein, the term “article” may refer to, but need not be limited to, dishes, pots, pans, silverware, and other cooking utensils and items that can be cleaned in a dishwashing appliance. The term “wash cycle” is intended to refer to one or more periods of time during the cleaning process where a dishwashing appliance operates while containing articles to be washed and uses a detergent and water, preferably with agitation, to e.g., remove soil particles including food and other undesirable elements from the articles. The term “rinse cycle” is intended to refer to one or more periods of time during the cleaning process in which the dishwashing appliance operates to remove residual soil, detergents, and other undesirable elements that were retained by the articles after completion of the wash cycle. The term ‘drying cycle” is intended to refer to one or more periods of time in which the dishwashing appliance is operated to dry the articles by removing fluids from the wash chamber. The term “fluid” refers to a liquid used for washing and/or rinsing the articles and is typically made up of water that may include other additives such as detergent or other treatments. 
         [0025]      FIGS. 1 and 2  depict an exemplary domestic dishwasher  100  that may be configured in accordance with aspects of the present disclosure. For the particular embodiment of  FIGS. 1 and 2 , the dishwasher  100  includes a cabinet  102  having a tub  104  therein that defines a wash chamber  106 . The tub  104  includes a front opening (not shown) and a door  120  hinged at its bottom  122  for movement between a normally closed vertical position (shown in  FIGS. 1 and 2 ), wherein the wash chamber  106  is sealed shut for washing operation, and a horizontal open position for loading and unloading of articles from the dishwasher. Latch  123  is used to lock and unlock door  120  for access to chamber  106 . 
         [0026]    Upper and lower guide rails  124 ,  126  are mounted on tub side walls  128  and accommodate roller-equipped rack assemblies  130  and  132 . Each of the rack assemblies  130 ,  132  is fabricated into lattice structures including a plurality of elongated members  134  (for clarity of illustration, not all elongated members making up assemblies  130  and  132  are shown in  FIG. 2 ). Each rack  130 ,  132  is adapted for movement between an extended loading position (not shown) in which the rack is substantially positioned outside the wash chamber  106 , and a retracted position (shown in  FIGS. 1 and 2 ) in which the rack is located inside the wash chamber  106 . This is facilitated by rollers  135  and  139 , for example, mounted onto racks  130  and  132 , respectively. A silverware basket (not shown) may be removably attached to rack assembly  132  for placement of silverware, utensils, and the like, that are otherwise too small to be accommodated by the racks  130 ,  132 . 
         [0027]    The dishwasher  100  further includes a lower spray-arm assembly  144  that is rotatably mounted within a lower region  146  of the wash chamber  106  and above a tub sump portion  142  so as to rotate in relatively close proximity to rack assembly  132 . A mid-level spray-arm assembly  148  is located in an upper region of the wash chamber  106  and may be located in close proximity to upper rack  130 . Additionally, an upper spray assembly  150  may be located above the upper rack  130 . 
         [0028]    The lower and mid-level spray-arm assemblies  144 ,  148  and the upper spray assembly  150  are part of a fluid circulation assembly  152  for circulating water and dishwasher fluid in the tub  104 . The fluid circulation assembly  152  may also include a pump  154  located in a machinery compartment  140  located below the bottom sump portion  142  (i.e. bottom wall) of the tub  104 , as generally recognized in the art. Each spray-arm assembly  144 ,  148  includes an arrangement of discharge ports or orifices for directing washing liquid onto dishes or other articles located in rack assemblies  130  and  132 . The arrangement of the discharge ports in spray-arm assemblies  144 ,  148  provides a rotational force by virtue of washing fluid flowing through the discharge ports. The resultant rotation of the lower spray-arm assembly  144  provides coverage of dishes and other dishwasher contents with a washing spray. 
         [0029]    The dishwasher  100  is further equipped with a controller  137  to regulate operation of the dishwasher  100 . The controller may include one or more memory devices and one or more microprocessors, such as a general or special purpose microprocessors operable to execute programming instructions or micro-control code associated with a cleaning cycle. The memory may represent random access memory such as DRAM, or read only memory such as ROM or FLASH. In one embodiment, the processor executes programming instructions stored in memory. The memory may be a separate component from the processor or may be included onboard within the processor. 
         [0030]    The controller  137  may be positioned in a variety of locations throughout dishwasher  100 . In the illustrated embodiment, the controller  137  may be located within a control panel area  121  of door  120  as shown in  FIG. 1 . In such an embodiment, input/output (“I/O”) signals may be routed between the control system and various operational components of dishwasher  100  along wiring harnesses that may be routed through the bottom  122  of door  120 . Typically, the controller  137  includes a user interface panel/controls  136  through which a user may select various operational features and modes and monitor progress of the dishwasher  100 . In one embodiment, the user interface  136  may represent a general purpose I/O (“GPIO”) device or functional block. In one embodiment, the user interface  136  may include input components, such as one or more of a variety of electrical, mechanical or electro-mechanical input devices including rotary dials, push buttons, and touch pads. The user interface  136  may include a display component, such as a digital or analog display device designed to provide operational feedback to a user. The user interface  136  may be in communication with the controller  137  via one or more signal lines or shared communication busses. 
         [0031]    It should be appreciated that the invention is not limited to any particular style, model, or configuration of dishwasher. The exemplary embodiment depicted in  FIGS. 1 and 2  is for illustrative purposes only. For example, different locations may be provided for user interface  136 , different configurations may be provided for racks  130 ,  132 , and other differences may be applied as well. 
         [0032]    As shown in  FIGS. 2 and 3 , an elongated heating element  170  is located in wash chamber  106  and is positioned above sump portion  142 . Heating element  170  may be e.g., an electrically resistant heating element such as a type sold under the name CALROD®. Heating element  170  provides heat energy during a wash, rinse, and/or drying cycle to e.g., heat a fluid introduced into wash chamber  106  and/or to assist with drying articles. 
         [0033]    Referring now specifically to  FIGS. 2 ,  3 , and  4 , an exemplary embodiment of a filtering system  200  is located near front  202  and in sump portion  142 . As shown, sump portion  142  includes a filter receptacle  204  into which a filter cartridge  206  is removably received. Filter cartridge  206  has a top  208  that the user can grasp to remove filter cartridge  206  from receptacle  204  in sump portion  142  whereby e.g., filter cartridge  206  may be cleaned or replaced. A coarse filter  212  covers a recess  214  in sump portion  142 . Filter cartridge  206  can be removed from receptacle  204  by sliding along axial direction A ( FIG. 7 ). 
         [0034]    Filtering system  200  removes soiled particles from the fluid that is recirculated through the wash chamber  106  during operation of dishwasher  100 . After the fluid is filtered by passing through filter media of filter cartridge  206 , it is fed to the inlet  155  of pump  154  for return to the wash chamber  106  by way of fluid recirculation assembly  152 . After being sprayed onto articles in the dishwashing appliance using one or more of spray elements  144 ,  148 , and  150 , the fluid eventually flows to sump portion  142 . Based on the shape of sump portion  142  (see  FIG. 2 ), fluid flows through into an internal chamber  216  of filter cartridge  206  defined by a cylindrically-shaped wall  219  of filter cartridge  206 . 
         [0035]      FIGS. 4 ,  5 , and  6  provide schematic views of the operation of an exemplary filter system  200  as may be used with system  200  shown in  FIGS. 2 and 3 . Filter system  200  is in fluid communication with pump inlet  155  and is located upstream of pump inlet  155 . As shown by arrows F, fluid can flow from chamber  216  and through one of the plurality of filter media  218 ,  220 , or  222  of filter cartridge  206  whereby particulates are removed from the fluid as will be further described. Although three filter media are shown for this exemplary embodiment, the present invention includes filter systems having 2, 4 or more filter media as well. 
         [0036]    After passing through one the filter media  218 ,  220 , or  222 , filtered fluid eventually travels to pump inlet  155  to be returned to the wash chamber by pump  154  which is in fluid communication with spray arm assemblies  144  and  148  as previously described. Filtering system  200  acts to clean soil particles from the fluid and protect pump  154  from clogging as the fluid is recirculated during the cleaning process of the dishwashing appliance  100  such as e.g., a wash or rinse cycle of appliance  100 . 
         [0037]    In order to avoid clogging of filter cartridge  206  during operation of appliance  100 , filter system  200  includes a diverter mechanism  224  positioned downstream of the filter cartridge  206  and upstream of pump inlet  155 . Diverter mechanism  224  is configured to selectively determine through which of the filter media  218 ,  220 , or  222  the fluid will flow as illustrated by the different fluid paths in  FIGS. 4 ,  5 , and  6 . 
         [0038]    As shown, filter cartridge  206  defines an axial direction A ( FIG. 7 ), radial direction R, and circumferential direction C. Filter media  218 ,  220 , and  222  are positioned proximate or adjacent to each other along circumferential direction C. Each one of the filter media is configured for removing different sized and/or types of particulates than the other filter media. 
         [0039]    Filter system  200  also includes a plurality of fluid channels  228 ,  234 , and  240 —each with a fluid outlet positioned downstream of a fluid inlet. For example, fluid channel  228  has a fluid inlet  226  and a fluid outlet  230 . Fluid channel  234  has a fluid inlet  232  and a fluid outlet  236 . Fluid channel  240  has a fluid inlet  238  and a fluid outlet  242 . 
         [0040]    Each fluid inlet is positioned to receive filtered fluid from one of the plurality of filter media  218 ,  220 , and  222 . For example, referring to  FIG. 4 , fluid inlet  226  of fluid channel  228  is positioned to receive filtered fluid from first filter media  218 . Referring to  FIG. 5 , fluid inlet  232  of fluid channel  234  is positioned to receive filtered fluid from second filter media  220 . As shown in  FIG. 6 , fluid inlet  238  of fluid channel  240  is positioned to receive filtered fluid from third filter media  222 . 
         [0041]    Diverter mechanism  224  selectively places the fluid outlet of each fluid channel in fluid communication with pump inlet  155  depending upon which filter media is desired for use.  FIG. 4  shows a flow of filtered fluid to pump inlet  155  from first filter media  218 ,  FIG. 5  shows a flow of filtered fluid to pump inlet  155  from second filter media  220 , and  FIG. 6  shows a flow of filtered fluid to pump inlet  155  from third filter media  222 . 
         [0042]    By choosing the filter media so that each removes different sizes of particles from the fluid, filtering system  200  can be used to adjust the degree of filtration to the amount and size of particles present at different times during the cleaning process. For example, the filter media can be chosen using diverter mechanism  224  such that progressively finer filtration can be used—i.e. filtering of smaller and smaller particles by selecting between filter media  218 ,  220 , and  222 —as the cleaning process for articles placed in appliance  100  progresses. 
         [0043]    Accordingly, in one exemplary aspect of the present invention, first filter media  218  is configured for removing particles in the size range of about 0.030″ to about 0.060″ or equipped with holes of this size. For example, the filter media may be a screen or mesh having holes in the size range of about 0.030″ to about 0.060″. Second filter media  220  is configured for removing particles in the size range of about 300 micron to about 600 micron or e.g., is equipped with holes of this size. Third filter media  222  is configured for removing particles in the size range of about 50 micron to about 150 micron or equipped with holes of this size. These size ranges are provided by way of example only. Other ranges may be used in certain exemplary embodiments of the invention as well. 
         [0044]    By way of example, controller  137  can provide a signal that causes diverter mechanism  224  to place fluid outlet  230  into fluid communication with pump inlet  155  to provide filtered fluid from first filter media  218 . Controller  137  then causes appliance  100  to execute a pre-wash cycle where only larger particles are removed (about 0.030″ to about 0.060″ or larger) without necessarily clogging filter cartridge  206 . Next, in a main wash cycle, controller  137  provides a signal that causes diverter mechanism  224  to place fluid outlet  236  into fluid communication with pump inlet  155  to provide filtered fluid from second filter media  220  such that smaller particles are removed (about 300 micron to about 600 micron or larger) without necessarily clogging filter cartridge  206 . Finally, in a rinse cycle, controller  137  provides a signal that causes diverter mechanism  224  to place fluid outlet  242  into fluid communication with pump inlet  155  to provide filtered fluid from third filter media  222  such that finest of particles are removed (about 50 micron to about 150 micron or larger) while avoiding clogs of filter cartridge  206 . Other methods of operation including different steps and cycles may be used with the present invention as well. 
         [0045]    Pressure drop in the fluid flowing through filter cartridge  206  is affected by e.g., hole size in the filter media as well as the percent of open area of the filter media. In certain exemplary embodiments of the invention, a percent of open area of about 30 percent may be used. In another embodiment, a percent of open area of about 40 percent may be used. In still another embodiment, a percent of open area of about 50 percent may be used. 
         [0046]    Tests were conducted to determine the effect of different filter media on a user&#39;s ability to perceive soils or particles on dishes. Soiled dishes were washed with fluid filtration using different media as indicated in Table I below. Three test subjects were asked to evaluate the cleanliness of the dishes based on the grades shown in Table II. The results indicate that users can detect particles as small as 150 microns on dishes and may be able to detect particles smaller than 100 microns on dishes. Accordingly, a filtering system that can remove particles in the range of about 50 micron to about 150 microns without clogging is advantageous. 
         [0000]    
       
         
               
               
             
               
               
               
               
             
           
               
                   
                 TABLE I 
               
             
             
               
                   
                   
               
               
                   
                 CU Grading for Grits (0, 1, 2) 
               
             
          
           
               
                   
                 Oper #1 
                 Oper #2 
                 Oper #3 
               
               
                 Grit/Sieve Size 
                 Dish #1 to 10 
                 Dish #11 to 20 
                 Dish #21 to 30 
               
               
                   
               
               
                 No soil 
                 0 
                 0 
                 0 
               
               
                  45μ 
                 0 
                 0 
                 0 
               
               
                  88μ 
                 1 
                 1 
                 0 
               
               
                 150μ 
                 1 
                 1 
                 1 
               
               
                 250μ 
                 2 
                 2 
                 2 
               
               
                   
               
             
          
         
       
     
         [0000]    
       
         
               
               
               
             
           
               
                   
                 TABLE II 
               
               
                   
                   
               
               
                   
                 # Grades 
                 Grits 
               
               
                   
                   
               
             
             
               
                   
                 0 
                 NONE 
               
               
                   
                 1 
                 LIGHT 
               
               
                   
                 2 
                 HEAVY 
               
               
                   
                   
               
             
          
         
       
     
         [0047]      FIGS. 7 ,  8 ,  9 ,  10 , and  11  provide views of another exemplary embodiment of filter system  200  located upstream of pump inlet  155  and with a diverter mechanism  224 . As shown, sump portion  142  of wash chamber  106  includes a filter receptacle  204  having an internal cavity  244  into which filter cartridge  206  is removably received. Filter receptacle  204  defines a plurality of openings  246  and  248  configured to allow fluid to flow from cavity  244 , through opening  246  or  248 , and through one of the filter media  218  or  220 . More specifically, openings  246  and  248  are spaced apart from each other about the filter receptacle  204  with each opening  246  positioned adjacent to filter media  218  and opening  248  positioned adjacent to filter media  220 . As previously indicated, the use of only two filter media is by way of example and more than two filter media may be used as well. 
         [0048]    Filter system  200  includes fluid channels  228  and  234  positioned about filter cartridge  206  and radially outward thereof. More particularly, for this exemplary embodiment, filter cartridge  206  is cylindrically-shaped as shown in  FIG. 7 , cavity  206  is also cylindrically-shaped, and fluid channels  228  and  234  are concentric with, and radially outward of, filter cartridge  206 . Channel  228  has a fluid inlet  226  and a fluid outlet  230  while channel  234  has a fluid inlet  232  and a fluid outlet  236 . 
         [0049]    Filter media  218  is positioned at or adjacent to fluid inlet  226  while filter media  220  is positioned at or adjacent to fluid inlet  232 . Accordingly, channel  228  provides fluid communication between opening  246  and fluid outlet  230  while channel  234  provides fluid communication between opening  248  and fluid outlet  236 . 
         [0050]    Diverter mechanism  224  is positioned downstream of filter cartridge  206  and upstream of pump inlet  155 . Mechanism  224  is configured to selectively place any one of the openings  246  or  248  into fluid communication with pump inlet  155 . More particularly, for this exemplary embodiment, diverter mechanism  224  includes a gate  250  that is slidably received into a slot  252 . Gate  250  can move along slot  252  to block the flow of filtered fluid through either fluid channel  228  or fluid channel  234  depending on which filter media  218  of  220  is selected. 
         [0051]    For example, in  FIGS. 10 and 11 , gate  250  is blocking fluid outlet  230  so that fluid flows only from fluid outlet  236  as shown by arrows F. Gate  250  can be operated by e.g., a linear actuator (not shown) connected to shaft  254  so that gate  250  can be manipulated by e.g., controller  137  during various cycles as previously described. 
         [0052]    This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.