Patent Publication Number: US-10307035-B2

Title: Dish treating appliance with leak detection

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims the benefit of and is a continuation of U.S. patent application Ser. No. 14/971,204, entitled “Dish Treating Appliance with Leak Detection,” filed Dec. 16, 2015, now U.S. Pat. No. 9,993,132, which is incorporated herein by reference in its entirety. 
    
    
     BACKGROUND 
     Contemporary automatic dish treating appliances for use in a typical household include a tub and at least one rack or basket for supporting soiled dishes within the tub. A spraying system with multiple sprayers can be provided for recirculating liquid throughout the tub to remove soils from the dishes. The spraying system can include various sprayers including a rotatable sprayer. A diverter valve having a rotatable valve body is used to selectively supply liquid from a recirculation pump to the various sprayers. The diverter can be located within the tub and a drive shaft extends through the tub to the rotatable valve body, with the rotation of the drive shaft effecting the rotation of the valve body. The interface between the drive shaft and the tub can provide a possible leak path from the tub. 
     BRIEF SUMMARY 
     In one aspect, an embodiment of the invention relates to a dish treating appliance for treating dishes according to an automatic cycle of operation, the dish treating appliance comprising a tub at least partially defining a treating chamber receiving dishes for treatment according to the automatic cycle of operation, multiple sprayers emitting a liquid into the treating chamber, and a diverter valve having a rotatable valve body, which can be rotated to discrete rotational positions to selectively fluidly couple with the multiple sprayers. A rotary drive is located exteriorly of the tub and comprises a housing defining an interior with a liquid leak reservoir, a motor carried by the housing, and an output shaft rotationally driven by the motor, extending through the housing and the tub, and operably coupled to the valve body. A printed circuit board (PCB) is located within the housing and has a liquid detection circuit comprising at least two traces extending into the liquid leak reservoir, wherein liquid leaking from the tub and running along the output shaft can enter the housing and flow along the liquid leak reservoir to short the two traces and provide an input to the liquid detection circuit. 
     In another aspect, an embodiment of the invention relates to a diverter valve assembly comprising a housing defining an interior with a liquid leak reservoir, a motor carried by the housing, an output shaft rotationally driven by the motor and extending through the housing, a printed circuit board (PCB) located within the housing and having a liquid detection circuit comprising at least two traces extending into the liquid leak reservoir, and a diverter valve having a rotatable valve body mounted to the output shaft, wherein liquid running along the output shaft can enter the housing and flow along the liquid leak reservoir to short the two traces and provide an input to the liquid detection circuit. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a perspective view of a dish treating appliance with a door opened and having a diverter valve according to an embodiment of the invention. 
         FIG. 2  is a partial schematic cross-sectional view of the dish treating appliance shown in  FIG. 1 , with the door closed. 
         FIG. 3  is a schematic view of a control system of the dish treating appliance of  FIG. 1 . 
         FIG. 4  is an exploded view of an exemplary diverter valve rotary drive that can be utilized in the dish treating appliance of  FIG. 2 . 
         FIG. 5  is an enlarged view of a printed circuit board that can be utilized in conjunction with the exemplary diverter valve rotary drive of  FIG. 4 . 
         FIG. 6  is a perspective view of a housing and a printed circuit board that can be utilized in the exemplary diverter valve rotary drive of  FIG. 4 . 
     
    
    
     DETAILED DESCRIPTION 
     Referring to  FIG. 1 , an automatic dish treating appliance  10  having a cabinet  12  defining an interior is illustrated. Depending on whether the dish treating appliance  10  is a stand-alone or built-in, the cabinet  12  can be a chassis/frame with or without panels attached, respectively. The dish treating appliance  10  shares many features of a conventional automatic dish treating appliance, which will not be described in detail herein except as necessary for a complete understanding of the invention. While the present invention is described in terms of a conventional dishwashing unit, it could also be implemented in other types of dishwashing units, such as in-sink dish treating appliances, multi-tub dish treating appliances, or drawer-type dish treating appliances. 
     The cabinet  12  encloses a tub  14  at least partially defining a treating chamber  16  for receiving dishes for treatment according to an automatic cycle of operation and defining an access opening  17 . The tub  14  has spaced top and lower or bottom walls  18  and  20 , spaced sidewalls  22 , a front wall  24 , and a rear wall  26 . In this configuration, the walls  18 ,  20 ,  22 ,  24 , and  26  collectively define the treating chamber  16  for treating or washing dishes. The bottom wall  20  may have a front lip  28  ( FIG. 2 ) with an upper portion  30  that may define a portion of the access opening  17 . The front wall  24  may be at least partially defined by a door  32  of the dish treating appliance  10 , which may be pivotally attached to the dish treating appliance  10  for providing accessibility to the treating chamber  16  through the access opening  17  for loading and unloading dishes or other washable items. More specifically, the door  32  may be configured to selectively open and close the access opening  17 . 
     Dish holders in the form of upper and lower dish racks  34 ,  36  are located within the treating chamber  16  and receive dishes for washing. The upper and lower racks  34 ,  36  may be mounted for slidable movement in and out of the treating chamber  16  for ease of loading and unloading. As used in this description, the term “dish(es)” is intended to be generic to any item, single or plural, that may be treated in the dish treating appliance  10 , including, without limitation; utensils, plates, pots, bowls, pans, glassware, and silverware. While not shown, additional utensil holders, such as a silverware basket on the interior of the door  32  or on a sidewall  22 , can also be provided. 
     Referring to  FIG. 2 , the major systems of the dish treating appliance  10  and their interrelationship may be seen. For example, a liquid recirculation system  38  is provided for spraying liquid within the treating chamber  16  to treat any dishes located therein. The liquid recirculation system  38  may include one or more sprayers configured to emit a corresponding spray of liquid into the treating chamber  16 . In the exemplary illustration, there are six sprayers: a first lower spray assembly  40 , a second lower spray assembly  42 , a third lower spray assembly  44 , a first mid-level spray assembly  46 , a second mid-level spray assembly  48 , and an upper spray assembly  50 . While six sprayers have been illustrated it will be understood that any number of sprayers can be included in the dish treating appliance, located in virtually any part of the treating chamber, and that at least one of the multiple sprayers can be included as a spray manifold having a plurality of nozzles. Such a spray manifold is set forth in detail in U.S. Pat. No. 7,594,513, issued Sep. 29, 2009, and titled “Multiple Wash Zone Dishwasher,” which is incorporated herein by reference in its entirety. 
     A sump  52  and pump assembly  53  can be included in the liquid recirculation system  38 . The sump  52  collects the liquid sprayed in the treating chamber  16  and can be formed by a sloped or recessed portion of a bottom wall  20  of the tub  14 . The pump assembly  53  can include both a wash or recirculation pump  54  and a drain pump  56 . The drain pump  56  can draw liquid from the sump  52  through a drain inlet  55  and pump the liquid out of the dish treating appliance  10  to a household drain line  57 . The recirculation pump  54  can draw liquid from the sump  52  and pump the liquid to the one or more of the spray assemblies  40 - 50  to supply liquid into the treating chamber  16 . While the pump assembly  53  is illustrated as having separate drain and recirculation pumps  54  and  56  in an alternative embodiment, the pump assembly  53  can include a single pump configured to selectively supply wash liquid to either the spray assemblies  40 - 50  or the drain line  57 , such as by configuring the pump to rotate in opposite directions, or by providing a suitable valve system. While not shown, a liquid supply system can include a water supply conduit coupled with a household water supply for supplying water to the sump  52 . 
     As shown herein, the recirculation pump  54  has a pump inlet  58  fluidly coupled to the treating chamber  16  via the sump  52  and a pump outlet  60  in fluid communication with a diverter valve  62 . The diverter valve  62  is coupled to a rotary drive  102  by an output shaft  112 . A number of liquid conduits  64 ,  66 ,  68 ,  70 ,  72 , and  74  in turn fluidly couple the diverter valve  62  to the spray assemblies  40 - 50 , respectively. In this manner, the pump outlet  60  is fluidly coupled to the spray assemblies  40 - 50  for discharging wash liquid from the recirculation pump  54  to the spray assemblies  40 - 50 . As illustrated, liquid can be supplied to the spray assemblies  42 - 50  through liquid conduits  66 ,  68 ,  70 ,  72 , and  74  that extend generally rearward from the recirculation pump  54  and upwardly along a rear wall of the tub  14 . Liquid can be supplied to the spray assembly  40  through the liquid conduit  64 . 
     The diverter valve  62  can control the flow of liquid within the dish treating appliance  10 . While the diverter valve  62  has been illustrated as being located in the middle of the tub  14  it will be understood that the diverter valve  62  can be located in any suitable location. The diverter valve  62  allows liquid to be selectively supplied to a subset of all of the sprayers, including to only a single sprayer, and/or simultaneously to all of the sprayers. The sump  52 , recirculation pump  54 , spray assemblies  40 - 50 , and liquid conduits  64 - 74  collectively form a recirculation flow path in the liquid recirculation system  38 . It will be understood that the recirculation flow path includes multiple recirculation circuits, with each circuit coupled to at least one of the sprayers forming the spray assemblies  40 - 50 . The recirculation pump  54  may be fluidly coupled to one or more of the circuits such that it draws liquid in through the pump inlet  58  and sump  52  and delivers it to one or more of the spray assemblies  40 - 50  through the liquid conduits  64 - 74  depending on the operation of the diverter valve  62 . The liquid is sprayed back into the treating chamber  16  through the spray assemblies  40 - 50  and drains back to the sump  52  where the process may be repeated. 
     A heating system having a heater  78  can be located within or near the sump  52  for heating liquid contained in the sump  52 . A filtering system (not shown) can be fluidly coupled with the recirculation flow path for filtering the recirculated liquid. 
     A control panel or user interface  80  provided on the dish treating appliance  10  and coupled to a controller  82  may be used to select a cycle of operation. The user interface  80  may be provided on the cabinet  12  or on the outer panel of the door  32  and can include operational controls such as dials, lights, switches, and displays enabling a user to input commands to the controller  82  and receive information about the selected cycle of operation. The dish treating appliance  10  may further include other conventional components such as additional valves, a dispensing system for dispensing treating chemistries or rinse aids, spray arms or nozzles, etc.; however, these components are not germane to the present invention and will not be described further herein. 
     As illustrated in  FIG. 3 , the controller  82  may be provided with a memory  84  and a central processing unit (CPU)  86 . The memory  84  may be used for storing control software that may be executed by the CPU  86  in completing a cycle of operation using the dish treating appliance  10  and any additional software. For example, the memory  84  may store one or more pre-programmed cycles of operation that may be selected by a user and completed by the dish treating appliance  10 . The controller  82  may be operably coupled with one or more components of the dish treating appliance  10  for communicating with and controlling the operation of the components to complete a cycle of operation. For example, the controller  82  may be coupled with the recirculation pump  54 , the diverter valve  62 , and a printed circuit board (PCB) for circulation of liquid in the wash tub  14  and the drain pump  56  for drainage of liquid in the wash tub  14 . Further, the controller  82  may also be coupled with one or more temperature sensors  88 , which are known in the art and not shown for simplicity, such that the controller  82  may control the duration of the steps of the cycle of operation based upon the temperature detected. The controller  82  may also receive inputs from one or more other optional sensor, which are known in the art and not shown for simplicity. The controller  82  may also be coupled to a dispenser  90 , which may dispense a detergent during the wash step of the cycle of operation or a rinse aid during the rinse step of the cycle of operation. 
       FIG. 4  illustrates an exploded view of an example of a rotary drive  102  for a diverter valve  62  having a rotatable valve body. The rotary drive  102  comprises a housing having a lower housing  104  and an upper housing  106 , a motor  110  carried by the upper housing  106 , and a printed circuit board (PCB)  114 , which are located external to the tub  14 . An output shaft  112  protrudes through the top of the upper housing  106  and extends up to the diverter valve  62 , passing through the bottom wall  20  of the tub  14 . A lip seal  100  is provided around the output shaft  112  at the point at which it passes through the bottom wall  20  of the tub  14 . The lower housing  104  defines an interior with a liquid leak reservoir  108 . The motor  110  is mounted to or adjacent the exterior of the upper housing  106 . The valve body of the diverter valve  62  is mounted to the output shaft  112  such that the output shaft  112  is operably coupled to the rotatable valve body. The PCB  114  is located within the lower housing  104  and has two traces  122 . A gear train  130  operably couples the electric motor  110  to the output shaft  112 . In a contemplated embodiment, the gear train  130  is provided as a reduction gear train. 
     The rotary drive  102  further comprises a rotary position sensor  116  for the output shaft  112  wherein the PCB  114  forms a part of the rotary position sensor  116 . The rotary position sensor  116  also comprises a microswitch  118  that is mounted on the PCB  114  with pins  120  that connect to the two traces  122 . The rotary position sensor  116  also comprises a detented cam  124  and a cam follower  126 . The detented cam  124  is coupled to the output shaft  112 . The angular spacing and shape of the detents on the face of the detented cam  124  are unique to the different positions corresponding to the different outlets that can be defined by the diverter valve  62 . The cam follower  126  is coupled to the output shaft  112  and is located between the microswitch  118  and the detented cam  124  of the rotary position sensor  116 . There is further provided a biasing element  128  to urge the cam follower  126  against the cam  124 . 
     The operation of the dish treating appliance  10  with the rotary drive  102  for the diverter valve  62  as illustrated will now be described. The user will initially select a cycle of operation via the user interface  80 , with the cycle of operation being implemented by the controller  82  controlling various components of the dish treating appliance  10  to implement the selected cycle of operation in the treating chamber  16 . Examples of cycles of operation include normal, light/china, heavy/pots and pans, and rinse only. The cycles of operation can include one or more of the following phases: a wash phase, a rinse phase, and a drying phase. The wash phase can further include a pre-wash phase and a main wash phase. The rinse phase can also include multiple phases such as one or more additional rinsing phases performed in addition to a first rinsing. During such cycles, wash fluid, such as water and/or treating chemistry (i.e., water and/or detergents, enzymes, surfactants, and other cleaning or conditioning chemistry) passes from the recirculation pump  54  into the liquid recirculation system  38  and then exits through the spray assemblies  40 - 50 . 
     Turning now to the operation of the rotary drive  102  for the diverter valve  62 , the motor  110  can then be operated, including via the controller  82 , to rotationally drive the output shaft  112  by way of the gear train  130 . The output shaft  112  is driven to rotate such that the cam  124  pushes upon the microswitch  118  as the output shaft  112  rotates. The rotatable valve body and coupled detented cam  124  can be rotated to discrete rotational positions in order to selectively fluidly couple with at least one of the multiple spray assemblies  40 - 50 . The detented cam  124  indicates the intended position of the diverter valve  62  by the identifiable and distinguishable detent patterns on the cam  124  that determine which path the flow of liquid through the diverter valve  62  will take so that a different spray assembly can be fluidly coupled with the recirculation pump  54 . The lip seal  100  is provided around the output shaft  112  to prevent the leakage of liquid from around the output shaft  112  where it passes through the tub  14 . If the lip seal  100  experiences wear with repeated use and rotation, liquid can leak from around the output shaft  112  and collect in the liquid leak reservoir  108  of the lower housing  104 . 
       FIG. 5  illustrates an enlarged view of the PCB  114  with the attached microswitch  118 . The PCB comprises a main body  132  portion and an extension  134  that is a projection from the main body  132 . The two traces  122  extend along and are located on the extension  134 . These two traces  122  make up a liquid detection circuit. While the embodiment exemplified herein illustrates the liquid detection circuit being made up of two traces  122 , it is also contemplated more than two traces  122  could make up the liquid detection circuit. 
       FIG. 6  illustrates a perspective view of the lower housing  104  and the PCB  114  in the orientation in which it is positioned within the lower housing  104 . The interior of the lower housing  104  defines the liquid leak reservoir  108 . In a corner portion of the lower housing  104 , there is provided a pair of spaced walls  136 ,  138  that define a channel  140 . The PCB  114  resides within the channel  140  in such a way that the PCB  114  is mounted generally orthogonal to the channel  140 . The extension  134  of the PCB  114  extends into the channel  140  of the liquid leak reservoir  108  and towards a bottom surface  142  of the lower housing  104 . 
     Referring now to the operation of the liquid detection circuit of the PCB  114 , when liquid leaks from the tub  14  and runs along the output shaft  112 , the liquid can enter the area of the lower housing  104  and flow along within the liquid leak reservoir  108 . As the leaked liquid flows within the liquid leak reservoir  108  and towards the channel  140 , the liquid will come into contact with the at least two traces  122  provided on the extension  134  of the PCB  114  that extends into the channel  140  of the liquid leak reservoir  108 . When liquid contacts the two traces  122 , a short will occur in the PCB  114 , which is provided as an input to the liquid detection circuit. Under normal circumstances with no leaking of liquid occurring, there is no liquid present in the liquid leak reservoir  108  and the PCB  114  will operate as designed. Once a short has occurred, the controller  82  is no longer able to sense the position of the diverter valve  62 . When the controller  82  registers that it cannot sense the diverter valve  62  position for more than a predetermined number of consecutive cycles, the controller  82  can send a signal to disable the diverter valve  62  to wait for service and repair. Alternatively, the short will close the circuit sending a constant signal, which also can be used to indicate the leak. 
     In an alternate embodiment, it is also considered that the PCB  114  could be provided without the extension  134 , such that the PCB  114  does not extend into the channel  140  of the liquid leak reservoir  108 . In this embodiment, the liquid leak reservoir  108  would function as a basin. If liquid were to leak from the tub  14 , run along the output shaft  112 , and enter the area of the lower housing  104 , the liquid would accumulate and fill the liquid leak reservoir  108 . When the liquid reaches a high enough level within the liquid leak reservoir  108 , the liquid would contact the body  132  of the PCB  114 , resulting in a short occurring in the PCB  114 , which provides an input to the liquid detection circuit. Once this short has occurred, the controller  82  is no longer able to sense the position of the diverter valve  62 . When the controller  82  registers that it cannot sense the position of the diverter valve  62 , the controller  82  can send a signal to disable the diverter valve  62  to wait for service and repair. Furthermore, the controller  82  can be configured to disable the dish treating appliance  10  entirely, such that a service call is required before the dish treating appliance  10  can execute a next cycle of operation. 
     The above-described embodiments provide a variety of benefits including that a diverter valve can be provided with a simple method for early detection of leaking along the seal of the diverter valve. The providing leak sensing concept is relatively low cost and upgrades the functionality of the microswitch and the PCB in order to improve moisture resistance capability and maintain the long lasting durability of the dish treating appliance. Being able to quickly detect any leaks present allows for prompt service and eliminates the risk of further wear or damage to the machine as a result of ongoing leaking. 
     To the extent not already described, the different features and structures of the various embodiments can be used in combination with each other as desired. That one feature cannot be illustrated in all of the embodiments is not meant to be construed that it cannot be, but is done for brevity of description. Thus, the various features of the different embodiments can be mixed and matched as desired to form new embodiments, whether or not the new embodiments are expressly described. All combinations or permutations of features described herein are covered by this disclosure. Further, while the invention has been specifically described in connection with certain specific embodiments thereof, it is to be understood that this is by way of illustration and not of limitation. 
     The patentable scope of the invention is defined by the claims, and can include other examples that occur to those skilled in the art. It will be understood that any features of the above-described embodiments can be combined in any manner. Reasonable variation and modification are possible within the scope of the forgoing disclosure and drawings without departing from the spirit of the invention, which is defined in the appended claims.