Patent Publication Number: US-10314458-B2

Title: Fluid circulation system for dishwasher appliances and related methods

Description:
FIELD OF THE INVENTION 
     The subject matter of the present disclosure relates generally to dishwasher appliances, and more particularly to fluid circulation and filtration systems within dishwasher appliances and related methods. 
     BACKGROUND OF THE INVENTION 
     Dishwasher appliances generally include a tub that defines a wash compartment. Rack assemblies can be mounted within the wash chamber of the tub for receipt of articles for washing. Spray assemblies within the wash chamber can apply or direct wash fluid towards articles disposed within the rack assemblies in order to clean such articles. Multiple spray assemblies can be provided including, e.g., a lower spray arm assembly mounted to the tub at a bottom of the wash chamber, a mid-level spray arm assembly mounted to one of the rack assemblies, and/or an upper spray assembly mounted to the tub at a top of the wash chamber. 
     Dishwasher appliances further typically include a fluid circulation system which is in fluid communication with the spray assemblies for circulating fluid to the spray assemblies. The fluid circulation system generally receives fluid from the wash chamber, filters soil from the fluid, and flows the filtered fluid to the spray assemblies. Additionally, unfiltered fluid can be flowed to a drain as required. 
     Some known fluid circulation systems utilize a large, flat, coarse filter and a cylindrical fine filter to filter soil. These filters are generally horizontally positioned within the fluid circulation system, and fluid typically flows through either the coarse filter or the fine filter as the fluid is flowed towards a pump of the fluid circulation system for recirculation. 
     More recently, improved filter arrangements have been utilized. These filters have perforated sidewalls which are generally vertically positioned and, for example, cylindrical. A pump is at least partially disposed within such a filter. Generally all wash fluid flowed to the pump is flowed through the filter. Such filter arrangements generally provide improved filtering and fluid flow relative to previously known filter arrangements. 
     However, some issues remain with such improved filter arrangements. For example, a fundamental issue with filters is that the filters must remain sufficiently clear to allow fluid to flow therethrough. Excess soil that remains on the filter can block such fluid flow. Accordingly, cleaning of the filter to prevent such blockages during operation is desired. One solution is to actively spray fluid at the filter to remove the soil therefrom. However, known arrangements which provide such active spraying constantly divert fluid from the spray assemblies and require that significantly more water is utilized during operation of the dishwasher appliance. The resulting increase in energy and water usage decreases the efficiency of the dishwasher appliance and is thus undesirable. 
     Accordingly, improved fluid circulation systems for dishwasher appliances are desired. In particular, fluid circulation systems which provide improved fluid filtering, and in particular improved filter cleaning during dishwasher appliance operation, would be advantageous. 
     BRIEF DESCRIPTION OF THE INVENTION 
     A method of operating a dishwasher appliance includes initiating a wash cycle of the dishwasher appliance. The wash cycle includes operating the dishwasher appliance in a wash mode for a first predetermined amount of time by positioning a diverter in a first position to direct a fluid flow to a spray assembly of the dishwasher appliance. The method also includes positioning the diverter in a second position to direct the fluid flow to a filter cleaning manifold for a second predetermined amount of time. The method further includes sensing the second position of the diverter with a position sensor. The method further includes performing a predetermined action after the second predetermined amount of time when the second position of the diverter is sensed before the first predetermined amount of time has elapsed. Additional aspects and advantages of the invention will be set forth in part in the following description, or may be obvious from the description, or may be learned through practice of the invention. 
     In accordance with one embodiment, a method of operating a dishwasher appliance is provided. The method includes initiating a wash cycle of the dishwasher appliance. The wash cycle includes operating the dishwasher appliance in a wash mode for a first predetermined amount of time and operating the dishwasher appliance in the wash mode includes positioning a diverter in a first position to direct a fluid flow to a spray arm of the dishwasher appliance. The method further includes positioning the diverter in a second position to direct the fluid flow to a filter cleaning manifold for a second predetermined amount of time. The method also includes sensing the second position of the diverter with a position sensor and returning the dishwasher appliance to the wash mode after the second predetermined amount of time when the second position of the diverter is sensed after the first predetermined amount of time has elapsed. The method further includes performing a predetermined action after the second predetermined amount of time when the second position of the diverter is sensed before the first predetermined amount of time has elapsed. 
     In accordance with another embodiment, a method of operating a dishwasher appliance is provided. The method includes operating the dishwasher appliance in a wash mode for a first period of time. The wash mode includes circulating fluid in the dishwasher appliance. Circulating fluid includes receiving fluid from a wash chamber of the dishwasher appliance, filtering the received fluid at a filtration rate with a filter medium, the filtration rate inversely proportional to a fouling status of the filter medium, and flowing the filtered fluid to a diverter such that the flow of filtered fluid urges the diverter to a first position. The diverter directs the filtered fluid to flow to a spray assembly when the diverter is in the first position. The method also includes initiating a filter cleaning mode after operating the dishwasher appliance in the wash mode for the first period of time. Initiating the filter cleaning mode includes moving the diverter to a second position. The diverter directs the filtered fluid to flow to a filter cleaning assembly when the diverter is in the second position. The diverter moves from the first position to the second position in response to a change in the filtration rate of the filter medium. The method further includes detecting that the dishwasher appliance is in the filter cleaning mode and operating the dishwasher in the filter cleaning mode for a second period of time. The method also includes performing a predetermined action after the second period of time. 
     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 
       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: 
         FIG. 1  provides a front view of a dishwasher appliance in accordance with one embodiment of the present disclosure; 
         FIG. 2  provides a side, cross-sectional view of a dishwasher appliance in accordance with one embodiment of the present disclosure; 
         FIG. 3  provides a cross-sectional view of a fluid circulation system for a dishwasher appliance with a diverter in a first position in accordance with one embodiment of the present disclosure; 
         FIG. 4  provides a cross-sectional view of the fluid circulation system of  FIG. 3  with the diverter in a second position; 
         FIG. 5  provides a cross-sectional view of the fluid circulation system of  FIG. 3  with the diverter in a third position; 
         FIG. 6  provides a top-down view of the fluid circulation system of  FIG. 3 ; 
         FIG. 7  provides a perspective view of a diverter according to an exemplary embodiment of the present disclosure; 
         FIG. 8  provides a cross-sectional view of the exemplary diverter of  FIG. 7  with a diverter valve shown in a first position; 
         FIG. 9  provides a cross-sectional view of the exemplary diverter of  FIG. 7  with a diverter valve shown in a second position; 
         FIG. 10  provides a perspective view of the diverter valve of  FIGS. 8 and 9 ; 
         FIG. 11  provides a perspective view of a portion of the exemplary diverter of  FIG. 7 ; 
         FIG. 12  provides a flowchart of a method of operating an appliance according to an exemplary embodiment of the present subject matter; and 
         FIG. 13  provides a flowchart of another method of operating an appliance according to an exemplary embodiment of the present subject matter. 
     
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     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. 
     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 “fluid” refers to a liquid used for washing and/or rinsing the articles and is typically made up of water that may include additives such as e.g., detergent or other treatments. 
     As used herein, the terms “first,” “second,” and “third” may be used interchangeably to distinguish one component from another and are not intended to signify location or importance of the individual components. The terms “upstream” and “downstream” refer to the relative direction with respect to fluid flow in a fluid pathway. For example, “upstream” refers to the direction from which the fluid flows, and “downstream” refers to the direction to which the fluid flows. The term “radially” refers to the relative direction that is substantially perpendicular to an axial centerline of a particular component, the term “axially” refers to the relative direction that is substantially parallel and/or coaxially aligned to an axial centerline of a particular component and the term “circumferentially” refers to the relative direction that extends around the axial centerline of a particular component. 
     The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting. As used herein, the singular forms “a,” “an,” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “comprises” and/or “comprising,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof. 
       FIGS. 1 and 2  depict an exemplary domestic dishwasher appliance  100  that may be configured in accordance with aspects of the present disclosure. For the particular embodiment of  FIGS. 1 and 2 , the dishwasher appliance  100  includes a cabinet  102  having a tub  104  therein that defines a wash chamber  106 . As shown, the dishwasher appliance  100  (such as the cabinet  102  thereof) defines a vertical direction V, a lateral direction L, and a transverse direction T, which are mutually orthogonal and define a coordinate system for the dishwasher appliance. 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. A latch  123  may be used to lock and unlock door  120  for access to chamber  106 . 
     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 . 
     The dishwasher appliance  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 bottom wall  142  of the tub  104  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 . 
     Each spray assembly  144 ,  148 ,  150  may include a spray arm or other sprayer and a conduit in fluid communication with the sprayer. For example, mid-level spray-arm assembly  148  may include a spray arm  160  and a conduit  162 . Lower spray-arm assembly  144  may include a spray arm  164  and a conduit  166 . Additionally, upper spray assembly  150  may include a spray head  170  and a conduit  172  in fluid communication with the spray head  170 . Each spray assembly  144 ,  148 ,  150  includes an arrangement of discharge ports or orifices for directing washing liquid received from diverter  300  onto dishes or other articles located in rack assemblies  130  and  132 . The arrangement of the discharge ports in spray-arm assemblies  144  and  148  provides a rotational force by virtue of washing fluid flowing through the discharge ports. The resultant rotation of the spray-arm assemblies  144  and  148  and the operation thereof using fluid from diverter  300  provides coverage of dishes and other dishwasher contents with a washing spray. Other configurations of spray assemblies may be used as well. For example, dishwasher  100  may have additional spray assemblies for cleaning silverware, for scouring casserole dishes, for spraying pots and pans, for cleaning bottles, etc. 
     The lower and mid-level spray-arm assemblies  144 ,  148  and the upper spray assembly  150  are part of a fluid circulation system  152  for circulating fluid in the dishwasher appliance  100 . The fluid circulation system  152  also includes various components for receiving fluid from the wash chamber  106 , filtering the fluid, and flowing the fluid to the various spray assemblies such as the lower and mid-level spray-arm assemblies  144 ,  148  and the upper spray assembly  150 . 
     Each spray assembly  144 ,  148 ,  150  may receive an independent stream of fluid, may be stationary, and/or may be configured to rotate in one or both directions. For example, a single spray arm may have multiple sets of discharge ports, each set receiving wash fluid from a different fluid conduit, and each set being configured to spray in opposite directions and impart opposite rotational forces on the spray arm. In order to avoid stalling the rotation of such a spray arm, wash fluid is typically only supplied to one of the sets of discharge ports at a time. 
     The dishwasher appliance  100  is further equipped with a controller  137  to regulate operation of the dishwasher appliance  100 . The controller may include one or more memory devices and one or more microprocessors, such as 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. 
     The controller  137  may be positioned in a variety of locations throughout dishwasher appliance  100 . In the illustrated embodiment, the controller  137  may be located within a control panel area  121  of door  120  as shown in  FIGS. 1 and 2 . 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. It should be noted that controllers  137  as disclosed herein are capable of and may be operable to perform any methods and associated method steps as disclosed herein. 
     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 , different combinations of spray assemblies may be utilized, and other differences may be applied as well. 
     Referring now to  FIGS. 3 through 5 , embodiments of portions of the fluid circulation system  152  of a dishwasher appliance  100  are illustrated. As shown, system  152  may include, for example, a sump  200  (shown in  FIG. 2 ) for receiving fluid from the wash chamber  106 . The sump  200  may be mounted to the bottom wall  142  and fluid may for example flow from the bottom wall  142  into the sump  200 . 
     Sump  200  may include and define, for example, a chamber  202  which receives the fluid from the wash chamber  106 . As illustrated, sump  200  may include a sidewall  204  and a base wall  208  which define the chamber  202 . For example, an inner surface  207  of the sidewall  204  may defined the chamber  202 . The sidewall  204  may extend from the base wall  208 , such as generally along the vertical direction V. As used herein, “generally” in the context of an angle or direction means within ten degrees, e.g., generally along the vertical direction may include within ten degrees of vertical. In some embodiments, the sidewall  204  may have a generally circular cross-sectional shape. Alternatively, the sidewall  204  may have a generally rectangular or other suitable polygonal cross-sectional shape, with multiple linear or curvilinear portions. Sidewall  204  may extend between a bottom end  205  (which may be connected to the base wall  208 ) and a top end  206  (which may be spaced from the base wall  208  along the vertical direction V). 
     Sump  200  may additionally include a skirt  209 . The skirt  209  may extend from the sidewall  204 , such as from the top end  206 , away from the chamber  202  and away from a filter  250  disposed at least partially within the chamber  202  (as discussed herein). For example, the skirt  209  may extend generally perpendicularly to sidewall  204  and/or generally radially from the sidewall  204 . As noted above, generally perpendicular is understood to include forming an angle within ten degrees of perpendicular, e.g., from eighty degrees to one hundred degrees, similarly, generally radial includes within ten degrees of radial. Fluid flowing into the chamber  202  may flow along skirt  209  until the skirt  209  reaches the sidewall  204 , and the fluid may then flow into the chamber  202 . Skirt  209  may, for example, be mounted to bottom wall  142 . 
     System  152  may further include a pump  210  which provides pressurized fluid flow to a diverter  300  via a conduit  220 . Pump  210  may include an impeller  212  which is disposed within the chamber  202 . In some embodiments, the impeller  212  may be enclosed within a housing  211 , and the housing  211  may include an intake  213  for drawing fluid into pump  210 , e.g., to the impeller  212 . Pump  210  may further include a motor  214  and a shaft  216  which connects the motor  214  and impeller  212 . For example, the motor  214  may be disposed within the chamber  202 , and may be hermetically sealed to prevent damage thereto from fluids within the chamber  202 . Alternatively, the shaft  216  may extend through the base wall  208 , and the motor  214  may be external to the chamber  202 . Impeller  212  may spin within the chamber  202  when activated by the motor  214  to influence the flow of fluid within the chamber  202 . 
     As further illustrated, a filter  250  may be disposed at least partially within the chamber  202 . As shown, the filter  250  surrounds the impeller  212 , and can additionally surround other components of the pump  210  such as the motor  214 . As illustrated, a filter  250  in accordance with the present disclosure may include a sidewall  252 . Filter  250  may further include a top wall  254 . Still further, filter  250  may include a base wall  255 . The sidewall  252  may extend generally along the vertical direction V, e.g., within 10 degrees of vertical, and between the top wall  254  and bottom wall  255 . Accordingly, the filter  250  may define an unfiltered volume  244  and a filtered volume  246  within the sump chamber  202 . That is, the unfiltered volume  244  may be the portion of sump chamber  202  upstream of the filter  250  with respect to a primary flow direction and the filtered volume  246  may be the portion of sump chamber  202  downstream of the filter  250  with respect to the primary flow direction. Further, it is understood that the unfiltered volume  244  is unfiltered relative to the filter  250 . In some embodiments, the sidewall  252  may have a generally circular cross-sectional shape, as illustrated in  FIG. 3 . Alternatively, the sidewall  252  may have a generally rectangular or other suitable polygonal cross-sectional shape, with multiple linear or curvilinear portions. 
     The sidewall  252  may include a filter media defining an outer surface  257  and an inner surface  258  of the sidewall  252 . Some embodiments may include filter media, e.g., screen or mesh, having pore or hole sizes in the range of about four thousandths (0.004 or 4/1000) of an inch to about eighty thousandths (0.08 or 80/1000) of an inch in diameter, or the pores may otherwise be sized and shaped to allow fluid flow therethrough, while preventing the flow of soil therethrough, thus filtering the fluid as the fluid flows into the filter  250  through the walls thereof. 
     As further illustrated, system  152  may further include a cleaning manifold  270 . The cleaning manifold may be configured to provide fluid to the outer surface  257  of the filter sidewall  252  for cleaning of the sidewall  252 . In particular, fluid flowing through the outlet conduit  220  may, as discussed herein, be diverted to the manifold  270 . The fluid in the manifold  270  may then be flowed from the manifold  270  towards and onto the outer surface  257 . The flow of fluid onto and on the outer surface  257  may advantageously clean the sidewall  252  by dislodging and removing soil from the sidewall  252 . In exemplary embodiments, the fluid exhausted from the cleaning manifold  270  may be exhausted in a plurality of streams, which may for example, be relatively high velocity jets of fluid, towards the outer surface  257 . The fluid may, for example, be exhausted generally along the vertical direction V onto the outer surface  257 , and may flow generally along the vertical direction V (e.g., generally parallel to the outer surface  257 ) to clean the sidewall  252 . 
     Cleaning manifold  270  may be disposed proximate the outer surface  257 , and may for example wrap around at least a portion of the perimeter of the sidewall  252 . As illustrated, manifold  270  may for example contact the outer surface  257 . Further, in exemplary embodiments, manifold  270  may be disposed proximate the top wall  254 . A plurality of apertures  272  may be defined in the manifold  270  for flowing fluid therethrough. Each aperture  272  may be oriented to direct fluid exhausted therefrom towards the outer surface  257 . For example, fluid exhausted from each aperture  272  may be flowed generally along the vertical direction V and along the outer surface  257 . 
     System  152  may further include a diverter  300 . Diverter  300  may be configured for selectively flowing fluid to the wash chamber  106  (such as via one or more of the spray assemblies) or to the cleaning manifold  270 , depending on the position of the valve  310 . Use of such a diverter  300  in accordance with the present disclosure may advantageously provide improved cleaning of the filter  250  without requiring an increase in water usage or an increase in energy usage or motor size. Such improved cleaning is provided by, for example, selective diversion of the fluid to the cleaning manifold  270  for periodic amounts of time to clean the filter  250 , such as the sidewall  252  thereof, as needed. Further, as discussed herein, the diverter  300  may advantageously only be utilized to divert fluid to the cleaning manifold  270  when cleaning is needed, and may automatically select between flowing fluid to the wash chamber  106  (such as via one or more of the spray assemblies) or to the cleaning manifold  270 . 
     As shown in  FIG. 7 , an exemplary diverter  300  may include an inlet  302  in fluid communication with the pump  210 , e.g., via conduit  220 , for receiving a flow of fluid from pump  210  that is to be supplied to spray assemblies  144 ,  148 , and/or  150  or cleaning manifold  270 , as well as other fluid-using components during cleaning operations. As stated, pump  210  receives fluid from, e.g., sump  200  and provides a fluid flow to diverter  300 . The exemplary diverter  300  includes a plurality of outlets, e.g., as illustrated in  FIG. 7 , the diverter  300  may include four outlets, including first outlet  303 , second outlet  304 , third outlet  305 , and fourth outlet  306 . Diverter  300  includes a valve  310  (see, e.g.,  FIG. 8 ), more fully described below, that can be selectively switched between outlets  303 ,  304 ,  305 , and  306  by hydraulic actuation. 
     By way of example, first outlet  303  can be fluidly connected with upper spray assembly  150  and lower spray arm assembly  144  and second outlet  304  can be fluidly connected with mid-level spray arm assembly  148 . Third outlet  305  may be fluidly connected with another fluid-using component, e.g., for cleaning silverware. Fourth outlet  306  may be fluidly connected to cleaning manifold  270 . Other spray assemblies and connection configurations may be used as well. As such, the rotation of valve  310  in diverter  300  can be used to selectively place pump  210  in fluid communication with spray assemblies  144 ,  148 , or  150 , another fluid-using component, or cleaning manifold  270 , by way of outlets  303 ,  304 ,  305 , and  306 , as described in an exemplary embodiment below. 
     In other embodiments of the invention, two, three, or more than four outlets may be provided in diverter  300  depending upon e.g., the number of switchable outlets desired for selectively placing pump  210  in fluid communication with different fluid-using elements of appliance  100 . For example, in some embodiments, the plurality of outlets may include a first outlet and a second outlet, the second outlet in fluid communication with the cleaning manifold  270 . In some embodiments, the first outlet may be in fluid communication with one or more spray assemblies  144 ,  148 , and/or  150 , such as lower spray arm assembly  144  and/or upper spray assembly  150 . Also, some embodiments of the plurality of outlets may further include a third outlet in fluid communication with others of the spray assemblies  144 ,  148 , and/or  150 , such as mid-level spray arm  148 . As used herein, the terms “first,” “second,” and “third” do not necessarily denote order or sequence, e.g., in the foregoing example embodiments, the diverter may be configured to provide flow to the third outlet before the second outlet. 
     As may be seen in  FIGS. 8 and 9 , the exemplary diverter  300  includes a housing  314 . Housing  314  includes two portions which are spaced apart, e.g., along the vertical direction V. Thus, in the illustrated example, the housing  314  includes an upper portion  318  and a lower portion  320 , however, the terms “upper” and “lower” are used by way of example only and without limitation. Rather, portion  318  and portion  320  may be spaced apart along any suitable direction depending on the particular configuration of pump  210  and diverter  300 . Housing  314  defines a chamber  324  into which fluid flows through fluid inlet  302 . Chamber  324  also provides fluid communication to one or more of the outlets  303 ,  304 ,  305  and  306 . Valve  310  (best seen in  FIG. 10 ) is positioned within chamber  324  and defines an axial direction A, a radial direction R, and a circumferential direction C (see, e.g.,  FIG. 7 ). More particularly, valve  310  includes a circular main body or disk  356  with at least one aperture  372  defined therein, and a cylindrical shaft  340  that extends along the axial direction A and is received into a cylindrical well  342  formed in housing  314 . This cylindrical shaft  340  is slidably received within the well  342  of the housing  314 , such that valve  310  is rotatable about the axial direction A, e.g., along the circumferential direction C, relative to housing  314  and movable back and forth along axial direction A. 
     As can be seen by comparing  FIGS. 8 and 9 , valve  310  is movable along the axial direction A between a first position shown in  FIG. 8  and a second position shown in  FIG. 9 . In the first position shown in  FIG. 8 , valve  310  rests on lower portion  320  of housing  314 . In the second position shown in  FIG. 9 , valve  310  is pressed against upper portion  318  of housing  314 . For this exemplary embodiment, a top surface  360  ( FIG. 10 ) of valve  310  contacts an interior surface  362  of housing  314  when valve  310  is in the second position. 
     Movement of valve  310  back and forth between the first position shown in  FIG. 8  and the second position shown in  FIG. 9  is provided by two opposing forces: i) a flow of fluid, e.g., water, passing through diverter  300  that is counteracted by ii) a biasing element  370 . More particularly, when pump  310  is off, biasing element  370  pushes along axial direction A against valve  310  and forces valve  310  in a first direction, e.g., downward, along the axial direction A to the position shown in  FIG. 8 . Conversely, when there is a sufficient flow of fluid through diverter housing  314 , the momentum of the fluid will impact valve  310 , this momentum overcomes the force provided by biasing element  370  so as to shift valve  310  along axial direction A in a second direction opposing the first direction, e.g., upward and away from diverter lower portion  320  towards diverter upper portion  318 , to the second position shown in  FIG. 9 . 
     Disk  356  assists in capturing the momentum provided by fluid flow through chamber  324 . In addition, as shown in  FIG. 10 , a bottom surface  380  of disk  356  of valve  310  may further include a plurality of arcuate ribs  382 . These arcuate ribs  382  capture the momentum and of the fluid flow and tend to cause the valve  310  to rotate in only one direction. The arcuate ribs  382  cause the valve  310  to rotate in a clockwise manner about axial direction A when viewed from bottom of valve  310 . As shown in  FIG. 10 , the disk  256  may include a plurality of arcuate ribs  382 , one skilled in the art will appreciate that any number of arcuate ribs may be used. Similarly, the ribs may be different size, shape, or orientation depending on the needs of the application. 
     Valve  310  will remain in the second position until the fluid flow ends or drops below a certain flow rate. Then, biasing element  370  urges valve  310  along axial direction A away from diverter upper portion  318  towards diverter lower portion  320  and back into the first position shown in  FIG. 8 . As shown in the exemplary embodiment of  FIGS. 8 and 9 , the biasing element  370  extends between a boss  384  on the upper portion  318  of the housing  314  and the valve shaft  340  and is configured to urge the valve  310  toward the first position. In this regard, boss  384  may define a recess  386  into which a top end  388  of the biasing element  370  may be slidably received, and a bottom end  390  of the biasing element  370  may be received in a conically-shaped seat  392  defined, for example, at the bottom of an interior channel  394  of valve shaft  340 . The biasing element  370  of the illustrated embodiment in  FIGS. 8 and 9  includes a plunger  402  and a compression spring  408 . Plunger  402  may, for example, include a shaft  401  and a head  403 , the plunger head  403  may have a larger diameter than the plunger shaft  401  and a compression spring  408  may be received onto the plunger shaft  401  and compressed against the plunger head  403 . One skilled in the art will appreciate that the illustrated biasing element is only an example, and other types of biasing elements are possible. For example, in some embodiments, the biasing element may be a simple compression spring. 
     The movement of valve  310  back and forth along the axial direction A between the first and second positions shown in  FIGS. 8 and 9  also causes valve  310  to rotate about the axial direction A so that the aperture  372  switches between outlets  303 ,  304 ,  305 , and  306 . For this exemplary embodiment, a single movement in either direction, e.g., from the first position to the second position or vice versa, causes valve  310  to rotate forty-five degrees. Accordingly, valve  310  rotates about the axial direction A by a total of ninety degrees each time valve  310  is moved out of, and then returned to, the second position ( FIG. 9 ). 
     As noted above, disk  356  of valve  310  may include an aperture  372 , which may be selectively placed in fluid communication with one of outlets  303 ,  304 ,  305 , and  306  to provide fluid flow to spray assemblies  144 ,  148 , and  150 , etc. For example, disk  256  may be rotated so as to place aperture  372  in fluid communication with one of outlets  303 ,  304 ,  305 , and  306 . In other embodiments, it is also possible to provide two or more apertures which may be in fluid communication with one or more of the outlets  303 ,  304 ,  305 , and  306  at a time. As shown in  FIGS. 6 and 7 , fluid outlets  303 ,  304 ,  305 , and  306  are spaced apart circumferentially on upper portion  318  of housing  314  by ninety degrees. Thus, each time valve  310  travels from and then returns to the second position, as described above, the valve  310 , and more particularly the aperture  372  in the disk  356  thereof, rotates ninety degrees and thereby moves from one outlet, e.g., first outlet  303 , to the next outlet, e.g., second outlet  304 . 
     As described below, the diverter  300  may include a positioning assembly for rotating the valve  310 , and in particular the diverter disk  356  thereof, about the axial direction incrementally through a plurality of angular positions. For example, each incremental rotation may include a first rotation as the valve  310  travels from the second position to the first position along the axial direction A and a second rotation as the valve  310  returns to the second position from the first position. The plurality of angular positions of the disk  356  may correspond to the plurality of outlets  303 ,  304 ,  305 , and  306  from the diverter  300  such that the aperture  372  is aligned with a respective one of the plurality of outlets  303 ,  304 ,  305 , and  306  in each of the plurality of angular positions. In various embodiments, the plurality of angular positions may include two angular positions spaced apart by one hundred and eighty degrees and the plurality of outlets may include two outlets spaced apart by one hundred and eighty degrees, the plurality of angular positions may include three angular positions spaced apart by sixty degrees and the plurality of outlets may include three outlets spaced apart by sixty degrees, or the plurality of angular positions may include four angular positions spaced apart by ninety degrees and the plurality of outlets may include four outlets spaced apart by ninety degrees. Several other variations and combinations are possible, for example, the disk  356  may include a plurality of apertures  372  and may rotate through a greater number of angular positions than there are outlets, e.g., to selectively provide fluid flow to one or more outlets at a time. 
     Although the illustrated embodiment shows a valve  310  including diverter disk  356  having one aperture  372  and rotating in ninety degree increments, one skilled in the art will appreciate that this configuration is provided only as an example. Diverter disk  256  may have more apertures and may be indexed in different increments. Similarly, housing  314  may have more or fewer than four outlets. For example, the disk  356  may rotate in one hundred twenty degree increments such that the aperture  372  travels between three outlets, the three outlets equidistantly spaced apart along the circumferential direction of upper portion  318  of housing  314 . 
     A positioning assembly including a plurality of guide element  330 ,  332  and/or positioning cams  352  may be provided in some exemplary embodiments. Referring now to  FIG. 11 , a cylindrically-shaped boss  384  extends along axial direction A from upper portion  318  of housing  314  into an interior channel  394  ( FIGS. 8 and 9 ) defined by valve  310 . As mentioned above, boss  384  defines recess  386  into which a first end  388  of biasing element  370  is received. Boss  384  also includes a plurality of guide elements  330  and  332  that are spaced apart from each other along circumferential direction C and extend radially outward from the boss  384 . Upper guide elements  330  and lower guide elements  332  are spaced apart along axial direction A and are also offset from each other along circumferential direction C. More particularly, as best seen in  FIG. 11 , along axial direction A, each of upper guide elements  332  is aligned with a gap positioned between a respective pair of the lower guide elements  330 . Conversely, each of lower guide elements  330  is aligned with a gap between a respective pair of upper guide elements  332 . 
     As stated and shown, boss  384  is received into an interior channel  394  defined by the shaft  340  of valve  310 . As may be seen in  FIGS. 8 and 9 , a plurality of cams  352  are positioned on the interior channel  394  of the cylindrical valve shaft  340  and project radially inward (i.e., along radial direction R) from cylindrical shaft  340  into interior channel  394 . Each cam  352  is spaced apart from adjacent cams  352  along the circumferential direction C, and each cam  352  is at the same axial position along the axial direction A. Accordingly, as described herein, one of skill in the art will appreciate that the guide elements  330 ,  332  and the cams  352  are configured to contact each other when the valve  310  moves into the second position so as to cause the valve  310  to rotate incrementally through a plurality of angular positions, e.g., to rotate forty five degrees as valve  310  travels from the first position to the second position, as described above. 
     Turning again to  FIGS. 3 through 5 , the diverter  300  may be configured to direct fluid from the pump  210  to the first outlet  303  in response to fluid pressure of the fluid from the pump  210  and to direct fluid from the pump  210  to another outlet, e.g., second outlet  304 , in response to a change in the fluid pressure of the fluid from the pump  210 . For example, upon an initial activation of the appliance  100 , e.g., at the initiation of a cleaning operation or cycle, the pump  210  may be activated, supplying fluid under pressure to chamber  324 , which, as described above may urge the diverter disk  356  to move from the first position as shown in  FIG. 8  to the second position as shown in  FIG. 9 , and further aperture  372  may move into alignment with first outlet  303  as the disk  356  moves to the second position. Accordingly, the first position prior to the initial activation may be a first axial position and may correspond to a first circumferential position, e.g., wherein aperture  372  is positioned between fourth outlet  306  and first outlet  303 . Further, the second position may be a second axial position and may correspond to a second circumferential position, e.g., wherein aperture  372  is aligned with first outlet  303 . At a subsequent time, the pump  210  may be slowed or deactivated, such that the fluid pressure changes, e.g., decreases, such that the biasing element  370  urges the valve  310  back to the first axial position, which may then correspond to a third circumferential position, e.g., wherein the aperture  372  is positioned between the first outlet  303  and the second outlet  304 . When the pump  210  may be sped up or reactivated, the fluid pressure may continue to change, e.g., increase, such that the valve  310  returns to the second axial position, this time corresponding to a fourth circumferential position, e.g., wherein the aperture  372  is aligned with the second outlet  304 . Such cycles, e.g., changes in pressure, may be repeated until the aperture  372  is aligned with fourth outlet  306 , which in the illustrated example would include the second axial position and an eighth circumferential position. For example, the pump  210  may be activated/deactivated and/or have its speed changed as in the foregoing description by the controller  137  according to a predetermined program or sequence of operations. 
     As another example, the pump  210  may change speeds or deactivate in response to a fluid level within the filter  250  and in particular within filtered volume  246 . As mentioned above, pump  210  may include an intake  213 . Further, the intake  213  may define an intake height, e.g., along the vertical direction V. When the fluid level within the filtered volume  246  falls below the intake height, fluid will not be drawn into the intake  213  and to the impeller  212 , such that the pump  210  will become air-locked and not draw liquid through intake  213 . As described in more detail below, fluid level within the filtered volume  246  may fall below the intake  213  when the filter  250  is fouled or in need of cleaning. Thus, as mentioned above, the diverter  300  may advantageously be utilized to divert fluid to the cleaning manifold  270  when cleaning is needed, and may automatically select between flowing fluid to the wash chamber  106  (such as via one or more of the spray assemblies) or to the cleaning manifold  270 . 
     The level of fluid within filtered volume  246  may be a function of two flow rates, first a rate of flow into the filtered volume  246  through the filter  250 , e.g., a filtration rate, and second a rate of flow out of the filtered volume  246 , e.g., a pumping rate of pump  210 . The filtration rate will be inversely proportional to a fouling status of the filter medium, for example, when relatively less soil is lodged in the holes or pores of the sidewall  252 , fluid flow through the sidewall  252  may be relatively higher, and the level of fluid within the filter  250  may be at, for example, a first height as shown in  FIG. 3 . However, as the fouling status increases, e.g., as more soil becomes lodged in the holes or pores of the filter medium, fluid flow through the sidewall  252  may be reduced, and the height of fluid within the filter  250  may be at, for example, a lower height as shown in  FIG. 4 . The height of fluid in the filter  250  can thus be utilized as an indicator of whether sidewall cleaning  252  is required. 
     As illustrated in  FIG. 4 , when the fluid height is reduced sufficiently, e.g., to below the level of the intake  213 , pump  210  deactivates, and the valve  310  may thus be moved to the first position by the biasing element  370 . Also, as described above, valve  310  will rotate as valve  310  moves along the axial direction from the second position, e.g., as shown in  FIG. 3 , to the first position, e.g., as shown in  FIG. 4 . With the pump off, e.g., the pumping rate at zero, the level of fluid within the filtered volume  246  will gradually increase due to the filtration rate until the fluid level again reaches at or above the intake  213 , such as a second height as is illustrated in  FIG. 5 , which is less than the first height as illustrated in  FIG. 3 . Once the fluid level within filtered volume  246  is sufficient to prime the pump  210 , e.g., is at or above the intake  213 , pump  210  may re-activate, pressurizing the chamber  324  which, as described above, moves the valve  310  back to the second axial position and to a subsequent circumferential position, e.g., such that the aperture  372  is aligned with fourth outlet  306  to provide fluid communication from chamber  324  to fourth outlet  306  and to cleaning manifold  270 . At this point, the dishwasher appliance  100  may be considered as operating in a filter cleaning mode, wherein the fluid flowing from the pump  210  is directed to cleaning manifold  270  to clean the outer surface  257  of the filter  250 , as described above. 
     When the diverter  300  directs fluid flow to the cleaning manifold  270 , the fouling status of the filter  250  is reduced as a result of the cleaning action of fluid issuing from apertures  272  in cleaning manifold  270 . Once the diverter  300  reaches a position wherein the diverter  300  directs fluid flow to the cleaning manifold  270 , the diverter  300  tends to stay in that position because the filtration rate remains sufficient to keep up with the pumping rate as long as the filter  250  is kept clean. Thus, the controller  137  may be configured to detect that the dishwasher appliance  100  is in the filter cleaning mode and, based upon certain additional conditions, such as an operation status of the dishwasher appliance  100 , the controller  137  may perform one or more of several possible predetermined actions. 
     For example, the controller  137  may be programmed to perform an operation cycle of the dishwasher appliance  100  which includes predetermined periods of time in which pump  210  is activated and deactivated. As described above, when the pump  210  is deactivated, the loss of pressure within the chamber  324  of diverter  300  causes the valve  310  of the diverter  300  to move to the first position ( FIG. 8 ), and when the pump  210  is subsequently reactivates, the fluid pressure causes the valve  310  to return to the second position ( FIG. 9 ), while the valve  310  also rotates along the circumferential direction C as the valve  310  travels between the first position and the second position to selectively provide fluid flow to one or more of the outlets  303 ,  304 ,  305 , and  306 . Accordingly, when the controller  137  activates and deactivates the pump  210 , the diverter  310  advances through a variety of positions and provides fluid flow to various fluid-using components of the dishwasher appliance  100 , including the cleaning manifold  270 . Thus, in some instances, the dishwasher appliance  100  may enter the filter cleaning mode in accordance with a predetermined operation cycle, e.g., where the diverter  300  advances to the position wherein the diverter  300  directs fluid flow to the cleaning manifold  270  based on activation and deactivation of the pump  210  by the controller  137 . 
     However, in other instances, the pump  210  may deactivate as a result of depletion of the fluid within the filtered volume  246  of the filter  250 , e.g., when the filter  250  is fouled and the pump  210  pumps fluid out faster than the fluid passes through the filter  250 , as described above. In such instances, it may be advantageous to return the dishwasher appliance  100  to the previous operating cycle, or it may be advantageous to drain the dishwasher appliance  100 , particularly the sump  200  thereof, and re-fill with cleaner water before returning the dishwasher appliance  100  to the previous operating cycle. It is to be understood that “previous operating cycle” refers to the cycle or mode in which the dishwasher appliance  100  was operating immediately prior to advancing to the filter cleaning mode. 
     The controller  137  may be configured to detect that the dishwasher appliance  100  is in the filter cleaning mode based upon a position sensor  374  ( FIG. 10 ). For example, the position sensor  374  may be located on valve  310  and may be configured to send a signal to the controller  137  when the valve  310  is positioned such that the aperture  372  is in fluid communication with the cleaning manifold  270 . 
     In some example embodiments, the position sensor  374  may be a reed switch sensor comprising a magnet and a plurality of reeds. As is understood in the art, the reeds may comprise a circuit and may be normally open or normally closed, wherein the reeds are configured to displace when in proximity to the magnet, e.g., to open or close the circuit in response to the proximity of the magnet. The general structure and operation of a reed switch are understood by those of skill in the art and are not described in further detail herein. In some example embodiments, the position sensor  374  may comprise a reed switch having the reeds thereof positioned on or near the housing  314  of the diverter  300  and the magnet thereof on the valve  310  such that when the valve  310  is positioned to provide fluid flow to the cleaning manifold  270  the magnet will be proximate to the reeds. 
       FIG. 12  illustrates an example method  1000  of operating a dishwasher appliance  100 . The method  1000  includes step  1010  of initiating a wash cycle of the dishwasher appliance  100 . As shown at step  1012 , the wash cycle includes operating the dishwasher appliance  100  in a wash mode for a first predetermined amount of time. Also, as shown at step  1014 , operating the dishwasher appliance  100  in the wash mode may include positioning a diverter  300  in a first position to direct a fluid flow to a spray assembly  144 ,  148 , or  150  of the dishwasher appliance  100 . The method  1000  further includes a step  1020  of positioning the diverter  300  in a second position to direct the fluid flow to a filter cleaning manifold  270  for a second predetermined amount of time and step  1030  of sensing the second position of the diverter  300  with a position sensor  374 . As discussed above, the diverter may be positioned in the second position as a result of sequential activation and deactivation of pump  210 . Also as discussed above, the sequential activation and deactivation of pump  210  may occur either in accordance with a predetermined operation cycle or in response to a fouling status of a filter  250 . When the second position of the diverter is sensed after the first predetermined amount of time has elapsed, e.g., after the wash mode has completed in accordance with the predetermined operation cycle, the method  1000  may then include step  1041  of returning the dishwasher appliance to the wash mode after the second predetermined amount of time. When the second position of the diverter is sensed before the first predetermined amount of time has elapsed, e.g., when the filter cleaning mode was initiated in response to a fouling status of the filter  250  before the wash mode has completed, the method  1000  may then include step  1042  of performing a predetermined action after the second predetermined amount of time. 
     In various embodiments, the predetermined action after the second period of time may include one of resuming operation according to the predetermined operation cycle, continuing to clean the filter for an additional period of time, or draining and re-filling the dishwasher appliance. In some embodiments, the predetermined action may be based on an operation status of the dishwasher appliance  100 , e.g., a percentage of completion of the wash cycle, at the time the diverter  300  was positioned in the second position to direct the fluid flow to the filter cleaning manifold  270 . For example, the predetermined action may include returning the dishwasher appliance  100  to the wash mode when the percentage of completion of the wash cycle is less than fifty percent. As another example, the predetermined action may include draining and re-filling the dishwasher appliance  100  when the percentage of completion of the wash cycle is greater than fifty percent. 
     In other example embodiments, the predetermined action may be based on the number of times that the second position of the diverter  300  has been sensed before the first predetermined amount of time has elapsed. For example, the predetermined action may include returning the dishwasher appliance  100  to the wash mode when the second position of the diverter  300  has been sensed less than three times before the first predetermined amount of time has elapsed. As another example, the predetermined action may include keeping the diverter  300  in the second position for an additional amount of time when the second position of the diverter  300  has been sensed two times before the first predetermined amount of time has elapsed. As a further example, the predetermined action may include draining and re-filling the dishwasher appliance when the second position of the diverter has been sensed three or more times before the first predetermined amount of time has elapsed. 
       FIG. 13  illustrates another example method  2000  of operating a dishwasher appliance  100 . The method  2000  includes a step  2010  of operating the dishwasher appliance in a wash mode for a first period of time. The wash mode includes circulating fluid in the dishwasher appliance. As shown at  2012 , circulating fluid includes receiving fluid from a wash chamber  106  of the dishwasher appliance  100  and filtering the received fluid at a filtration rate with a filter medium of a filter  250 . The filtration rate is inversely proportional to a fouling status of the filter medium. As shown at  2014 , circulating fluid also includes flowing the filtered fluid to a diverter  300  such that the flow of filtered fluid urges the diverter  300  to a first position. The diverter  300  directs the filtered fluid to flow to a spray assembly  144 ,  148 , or  150  when the diverter  300  is in the first position. 
     Still with reference to  FIG. 13 , method  2000  further includes a step  2020  of initiating a filter cleaning mode after operating the dishwasher appliance  100  in the wash mode for the first period of time. Initiating the filter cleaning mode includes moving the diverter  300  to a second position, the diverter  300  directs the filtered fluid to flow to a filter cleaning assembly  270  when the diverter  300  is in the second position. The diverter  300  moves from the first position to the second position in response to a change in the filtration rate of the filter medium of filter  250 . For example, when the filter fouls and clogs, the filtration rate decreases and the pump runs dry and deactivates, such that the biasing element  370  urges the valve  310  to the second position in response to the decreased filtration rate. Method  2000  also includes a step  2030  of detecting that the dishwasher appliance  100  is in the filter cleaning mode and a step  2040  of operating the dishwasher in the filter cleaning mode for a second period of time. The method  2000  further includes step  2050  of performing a predetermined action after the second period of time. 
     In some embodiments, the predetermined action may be based on an operation status of the dishwasher appliance  100 , e.g., operating the dishwasher appliance in the wash mode may include a first rinse cycle and a second rinse cycle subsequent to the first rinse cycle, and the predetermined action may be based on whether the first rinse cycle has been completed at the time that the filter cleaning mode is initiated. For example, the predetermined action may include returning the dishwasher appliance  100  to the wash mode when the filter cleaning mode was initiated during the first rinse cycle. As another example, the predetermined action may include draining and re-filling the dishwasher appliance  100  when the filter cleaning mode was initiated after the first rinse cycle has been completed. 
     In some embodiments, the predetermined action may be based on a number of times the filter cleaning mode has been initiated during a current operating cycle of the dishwasher appliance. For example, the predetermined action may include returning the dishwasher appliance  100  to the wash mode when the filter cleaning mode has been initiated less than three times during the current operating cycle of the dishwasher appliance  100 . As another example, the predetermined action may include continuing to clean the filter  250  for an additional period of time, e.g., operating the dishwasher appliance  100  in the filter cleaning mode for a third period of time when the filter cleaning mode has been initiated two times during the current operating cycle of the dishwasher appliance  100 . As still another example, the predetermined action may include draining and re-filling the dishwasher appliance  100  when the filter cleaning mode has been initiated three or more times during the current operating cycle of the dishwasher appliance  100 . 
     In additional example embodiments, the predetermined action may be based on an amount of time since the second position of the diverter  300  was last sensed and/or an amount of time since the filter cleaning mode was last initiated. 
     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 language of the claims.