Patent Publication Number: US-8968483-B2

Title: Method of using liquid in a dishwasher

Description:
BACKGROUND OF THE INVENTION 
     Contemporary dishwashers for use in a typical household include a tub for storing dishes during the implementation of a wash cycle within the tub for cleaning of the stored dishes. A reuse tank may be provided to store liquid captured from the tub during a previous wash/rinse phase of the wash cycle. The stored liquid may be used in the same or subsequent wash cycles. 
     BRIEF DESCRIPTION OF THE INVENTION 
     The invention relates to a method of operating a dishwasher having a treating chamber for receiving dishes according to an automatic cycle of operation, the method includes dispensing a detergent into the treating chamber, supplying of liquid to the treating chamber to mix with the detergent to form a wash liquid, storing a first portion of the wash liquid in a reuse tank in the dishwasher and using a second portion of the wash liquid in the treating chamber, supplying the first portion of the wash liquid from the reuse tank to the treating chamber, recirculating the first portion of the wash liquid through the treating chamber, and removing the wash liquid from the treating chamber. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a schematic, side view of a dishwasher according to a first embodiment of the invention. 
         FIG. 2  is a schematic view of a control system of the dishwasher in  FIG. 1 . 
         FIG. 3  is a flow chart of the operation of the dishwasher according to a second embodiment of the invention. 
         FIG. 4  is a schematic, side view of a dishwasher according to a third embodiment of the invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS OF THE INVENTION 
       FIG. 1  is a schematic, side view of a treating appliance according to a first embodiment of the invention, which is illustrated in the context of a dishwasher  10 . While the illustrated treating appliance is a dishwasher  10 , other treating appliances are possible, non-limiting examples of which include other types of dishwashing units, such as in-sink dishwashers, multi-tub dishwashers, or drawer-type dishwashers. The dishwasher  10 , which shares many features of a conventional automated dishwasher, will not be described in detail herein except as necessary for a complete understanding of the invention. 
     The dishwasher  10  may have a cabinet  12  defining an interior, which is accessible through a door  13 . The cabinet  12  may include a chassis or frame to which panels may be mounted. For built-in dishwashers, the outer panels are typically not needed. At least one tub  14  is provided within the interior of the cabinet  12  and defines a treating chamber  16  to receive and treat dishes according to a cycle of operation, often referred to a wash cycle whether or not washing occurs. The tub  14  has an open face that is closed by the door  13 . 
     For purposes of this description, the term “dish(es)” is intended to be generic to any item, single or plural, that may be treated in the dishwasher  10 , including, without limitation; utensils, plates, pots, bowls, pans, glassware, and silverware. 
     One or more dish racks, such as a lower dish rack  18  and an upper dish rack  20  may be provided in the treating chamber  16 . The racks  18 ,  20  hold dishes (not shown) that may be treated in the treating chamber  16 . The racks  18 ,  20  may be slid in and out of the treating chamber  16  through the opening closed by the door  13 . 
     A detergent dispenser  21  may be located in the door  13 . It will be understood that depending on the type of dishwasher and the type of detergent used, the detergent dispenser  21  may be incorporated into one dispensing mechanism. The detergent dispenser  21  may be of a single use dispenser type or a bulk dispenser type. In the case of bulk dispensing, the detergent and/or rinse aid can be selectively dispensed into the treating chamber  16  in a regulated quantity and at a predetermined time or multiple times during a cycle of operation. The detergent dispenser  21  may have a door or other mechanism through which the detergent may be dispensed. Further, in the case of a bulk dispenser the detergent dispenser  21  may include a pump or other mechanism for supplying a quantity of detergent to the treating chamber  16 . 
     A liquid supply system is provided for supplying liquid to the treating chamber  16  as part of a wash cycle for washing any dishes within the racks  18 ,  20 . The liquid supply system includes one or more liquid sprayers, which are illustrated in the form of spray arm assemblies  22 ,  24 ,  26 , that are provided within the treating chamber  16  and are oriented relative to the racks  18 ,  20  such that liquid sprayed from the spray arm assemblies  22 ,  24 ,  26  may be directed into one or more of the racks  18 ,  20 . 
     It should be noted that the stacked arrangement of the dish racks and the spray arm assemblies is not limiting to the invention. It merely serves to illustrate the invention. For example, the invention may be implemented in a stacked arrangement having a silverware basket, the lower and upper dish rack, and with upper, middle, and lower level spray arm assemblies having spray heads for the silverware basket alternatively arranged in between the lower and upper dish rack. 
     The liquid supply system may include a sump  30  to collect by gravity, liquid sprayed within the treating chamber  16 . The sump  30  is illustrated as being formed with or affixed to a lower portion of the tub  14  to collect liquid that may be supplied into or circulated in the tub  14  during, before, or after a cycle of operation. However, the sump  30  may be remote from the tub  14  and fluidly coupled by suitable fluid conduits. 
     A pump assembly  32  fluidly coupled to the sump  30  may also be included in the liquid supply system and may include a wash pump or recirculation pump  34  and a drain pump  36 . The recirculation pump  34  fluidly couples the sump  30  to the spray arm assemblies  22 ,  24 ,  26  through a spray arm supply conduit  37  to recirculate liquid that collects in the sump to the spray arm assemblies  22 ,  24 ,  26  for spraying on the racks  18 ,  20 . The drain pump  36  fluidly couples the sump  30  to a drain conduit  62  for draining liquid collected in the sump  30  to a household drain, such as a sewer line, or the like. 
     A reuse tank  52  for storing liquid captured during one or more phases/steps of a wash cycle for later use in the current wash cycle and/or a subsequent wash cycle may also be included in the liquid supply system. The reuse tank  52  may be fluidly coupled to the recirculation pump  34  by a reuse tank supply conduit  50  so that liquid from the sump  30  may be supplied to the reuse tank  52 . A control valve  48  controls the liquid from the recirculation pump  34  to either the spray arm supply conduit  37  or the reuse tank supply conduit  50 . The reuse tank  52  may also be fluidly coupled to the sump  30  by an outlet conduit  51  such that liquid in the reuse tank  52  may be supplied to the sump  30  for subsequent use. A control valve  56  is provided in the outlet conduit  51  to control the supply of liquid from the reuse tank  52  to the sump  30 . A supply conduit  64  may fluidly couple the reuse tank  52  to the drain pump  36  through a drain conduit  62  and a control valve  63 . The control valve  63  is provided to control the flow of liquid from the drain pump  36  to either the drain conduit  62  or the reuse tank  52 . 
     As illustrated, the physical relationship between the reuse tank  52  and the sump  30  uses gravity to supply the liquid from the reuse tank  52  to the sump  30 . Thus, liquid from the sump  30  may be supplied to the reuse tank  52  by either combination of recirculation pump  34 , control valve  56 , outlet conduit  51  or drain pump  36 , control valve  63 , supply conduit  64 , and valve  65 . With either configuration, the actuation of the corresponding control valve  48 ,  63  will redirect the output of the recirculation pump  34  or drain pump  36 , respectively, to the reuse tank  52 , through the corresponding conduit  50 ,  64  and the valve  65 . However, it is contemplated that the reuse tank  52  may be provided at other locations, some of which may be incapable of using gravity to supply the reuse liquid to the sump. Thus, it is contemplated that a pump could be provided to pump liquid from the reuse tank  52  to the sump  30 , regardless of whether gravity can be used to supply the reuse liquid. 
     While liquid may be provided to the reuse tank  52  through the tub  14  and the sump  30 , the liquid may be directly provided to the reuse tank  52 . For example, liquid having at least one of water, detergent, and treatment aid may be separately provided in the reuse tank  52  to form the liquid. Alternatively, premixed mixture having at least one of water, detergent, and treatment aid may be directly provided in the reuse tank  52  to clean the reuse tank  52 . 
     It is noted that the supplying of liquid from the sump  30  to the reuse tank  52  may be reiterated multiple times for the multiple wash/rinse phases of a cycle of operation until multiple capture steps may provide enough amount of liquid which is sufficient to fill up the reuse tank  52  while only one time capturing step during any wash/rinse phase may be performed. It is also noted that whole amount of liquid for any wash/rinse phase during a cycle of operation may be captured to the reuse tank  52  through either the recirculation pump  34  or drain pump  36  while only a portion of the liquid in the tub  14  may be captured and provided to the reuse tank  52 . 
     Further as illustrated, the liquid in the reuse tank  52  may be drained by supplying the liquid to the sump  30  and then actuating the drain pump  36 . It is contemplated that a separate drain conduit (not shown) can be provided from the reuse tank  52  to the drain pump  36  to directly drain the liquid in the reuse tank without the liquid entering the sump. 
     While the pump assembly  32  may include the recirculation pump  34  and the drain pump  36 , in an alternative embodiment, the pump assembly  32  may include a single pump, which may be operated to supply liquid to either the drain conduit  62  or the spray arm support conduit  37 , such as by rotating in opposite directions or by valves. 
     A water supply conduit  58  may fluidly couple a water supply to the treating chamber  16 . A control valve  59  may control the flow of water from the household supply to the treating chamber  16 . The water may be supplied to any portion of the treating chamber  16 . It is also contemplated that the water supply conduit  58  may supply water directly to the sump  30  or to a portion of the detergent dispenser  21 . 
     A control system having various components and sensors for controlling the flow and condition of the liquid to implement a wash cycle may be included in the dishwasher  10 . The control system includes a heater  38  that may be located within the sump  30  to selectively heat liquid collected in the sump  30 . The heater  38  may be an immersion heater in direct contact with liquid in the sump  30  to provide the liquid with predetermined heat energy. A temperature sensor such as a thermistor  42  may be provided in the sump  30  to provide an output that is indicative of the temperature of any fluid, liquid or air, in the sump  30 . A pH sensor  44  may also be located near the bottom of the wall or in the sump  30  and provide an output indicative of the pH of the liquid in the sump  30 . A turbidity sensor  71  may also be located in the sump  30 , near the bottom of the wall, or near the pump assembly  32  and provide an output that is indicative of the turbidity of the liquid in the sump  30 . 
     A heater  66  may be provided in the reuse tank  52  to heat the liquid in the reuse tank  52 . A thermistor  68  may be provided in the reuse tank and output a signal indicative of the temperature within the reuse tank  52 . Similar to the heater  38 , the heater  66  may also be in a direct fluid contact with liquid in the reuse tank  52  to provide heat energy to the liquid stored in the reuse tank  52 . The thermistor  68  may be positioned such that the thermistor  68  may be in direct fluid contact with liquid in the reuse tank  52  during measurement. A pH sensor  70  may be coupled to the reuse tank  52  to output a signal indicative of the pH of liquid in the reuse tank  52 . Additional sensors may be operably coupled to the reuse tank to monitor the characteristics of liquid in the reuse tank  52 . 
     It is also noted that additional sensors may be fluidly coupled to the tub  14  or reuse tank  52  to provide output indicative of condition of the liquid. Non-limiting examples of additional sensors include a turbidity sensor and a conductivity sensor. 
     A controller  40  may be included in the dishwasher  10  for implementing one or more cycles of operation. As seen in  FIG. 2 , the controller  40  is operably coupled to the pumps  34 ,  36 , heaters  38 ,  66 , control valves  48 ,  56 ,  59 ,  63 ,  65 , thermistors  42 ,  68 , pH sensors  44 ,  70 , and a turbidity sensor  71  to either control these components and/or receive their input for use in controlling the components. The controller  40  is also operably coupled to a user interface  72  to receive input from a user for the implementation of the wash cycle and provide the user with information regarding the wash cycle. In this way, the controller  40  can implement a wash cycle selected by a user according to any options selected by the user and provide related information to the user. 
     The controller  40  may also include a central processing unit (CPU)  80  and an associated memory  82  where various wash cycle and associated data, such as look-up tables, algorithms, may be stored. Non-limiting examples of treatment cycles include normal, light/china, heavy/pots and pans, and rinse only. One or more software applications, such as an arrangement of executable commands/instructions may be stored in the memory and executed by the CPU  80  to implement the one or more wash cycles. The controller  40  may further include a clock  84 . The clock  84  may be alternatively located in another component operably coupled to the controller  40 . 
     The user interface  72  provided on the dishwasher  10  and coupled to the controller  40  may include operational controls such as dials, lights, knobs, levers, buttons, switches, and displays enabling the user to input commands to the controller  40  and receive information about the selected treatment cycle. The user interface  72  may be used to select a treatment cycle to treat a load of dishes. Alternatively, the treatment cycle may be automatically selected by the controller  40  based on the soil levels sensed by any sensors in the dishwasher  10  to optimize the treatment performance of the dishwasher  10  for a particular load of dishes. 
     During operation of the dishwasher  10 , the controller  40  may be employed to control the components including the liquid supply system, the detergent dispenser  21 , and the pump assembly  32  to operate the dishwasher  10  according to a cycle of operation. In operation, liquid, such as water and/or treating chemistry (i.e., water and/or detergents, enzymes, surfactants, and other cleaning or conditioning chemistry), may enter the tub  14  and flows into the sump  30 . Liquid may then be directed back to the treating chamber through the spray assemblies  22 - 26 , to the ruse tank  52 , or to the drain conduit  62 . The drain pump  36  and/or the recirculation pump  34  may be used to store liquid in the reuse tank  52 . Any liquid and soils in the tub  14  may be drained by the drain pump  36 . 
     The dishwasher  10  may be operated in a variety of manners to obtain a variety of benefits. Including that, in one embodiment, the dishwasher  10  may be operated to store a first portion of the wash liquid in a reuse tank in the dishwasher and using a second portion of the wash liquid in the treating chamber. For example,  FIG. 3  is a flow chart of the operation of the dishwasher  10  according to a second embodiment of the invention. The sequence of steps depicted in  FIG. 4  is for illustrative purposes only, and is not meant to limit the method in any way as it is understood that the steps may proceed in a different logical order, additional or intervening steps may be included, or described steps may be divided into multiple steps, without detracting from the invention. The method may be implemented multiple times, either consecutively or intermittently, during, after or before a wash cycle. The method may be incorporated into a cycle of operation for the dishwasher  10 , such as prior to or as part of any phase of the wash cycle or the method may also be a stand-alone cycle. It is noted that the method may be used with or without the dishes placed within the treating chamber  16 . 
     The method  100  may begin at  102  by dispensing a detergent into the treating chamber  16 . More specifically, detergent may be dispensed from the detergent dispenser  21 . In the case where the detergent dispenser  21  may be of a single use dispenser type, the controller  40  may open a door of the detergent dispenser  21  to dispense the detergent into the treating chamber  16 . In the case where the detergent dispenser  21  is a bulk dispenser type dispenser the controller  40  may actuate a portion of the detergent dispenser  21 , such as a pump of the detergent dispenser to dispense the detergent into the treating chamber  16 . 
     At  104  a first amount of liquid, such as water, may be supplied to the treating chamber  16  to mix with the detergent to form a wash liquid. The control valve  59  may be operated to provide a flow of water from the household supply to the treating chamber  16 . When the liquid is supplied to the treating chamber  16 , the liquid may be collected in the sump  30  due to gravity. It is also contemplated that the liquid may be supplied directly to the sump  30 . Alternatively, it is contemplated that this may be done simultaneously with the addition of the detergent. For example, the water and the detergent may be pre-mixed before the mixture of water and the detergent is provided to the treating chamber  16 . It is also contemplated that liquid may be supplied from the reuse tank  52  to the treating chamber  16  to mix with the detergent to form a wash liquid at  104 . 
     At  106 , a first portion of the wash liquid may be stored in the reuse tank  52  while a second portion of the wash liquid may remain in the treating chamber for use of the second portion of the wash liquid. The first portion may be stored in the reuse tank through operation of the pump assembly  32 . It is contemplated that either the drain pump  36  or the recirculation pump  34  may be used to store the first portion of the wash liquid in the reuse tank  52 . More specifically, the first portion of the wash liquid may be drained through the drain pump  36 . The output of the drain pump  36  may be directed to the supply conduit  64  feeding the reuse tank  52  by the actuation of the control valve  63  until the first portion is stored. Alternatively, the control valve  48  may be actuated to direct the flow of liquid from the recirculation pump  34  to the reuse tank  52  to store the first portion of the wash liquid. More specifically, the output of the recirculation pump  34  may be directed to the conduit  50  feeding the reuse tank  52  by the actuation of the control valve  48  until the first portion is stored. The second portion of the wash liquid may then be used within the treating chamber  16 . 
     Regardless of which pump is used to store the first portion of the wash liquid in the reuse tank  52 , the controller  40  may control the pump to store the first portion of the wash liquid in the reuse tank  52 . It is contemplated that the first portion of wash liquid may be a predetermined amount and that a sensor such as a flow meter may be used to accurately store such an amount. Alternatively, a time-based approach may be used where the controller  40  operates the pump for a time period, which is sufficient to store the first portion of wash liquid. Such a time period may be empirically determined based on anticipated liquid volumes. The time-based approach runs the risk of under/over-shooting each of the portions if the volume condition varies from what was anticipated or for some reason the pump does not pump at the anticipated rate. 
     At  108 , after the storing of the first portion, the second portion of the wash liquid may be recirculated in the treating chamber  16 . More specifically, the second portion of the wash liquid may be recirculated to at least one of the spray arm assemblies  22 ,  24 ,  26  to provide a spray of liquid to clean the dishes in the dish racks  18 ,  20  in the treating chamber  16  according to a wash cycle. This may be done by directing the output of the recirculation pump  34  to the spray assemblies  22 - 26  through use of the control valve  48 . The recirculated second portion of the wash liquid may remove soil particles from any dishes within the treating chamber  16  and may form a wash liquid comprising a mixture of the second portion of the wash liquid and the soil particles. Alternatively, the second portion of the wash liquid may recirculate in the treating chamber  16  without the presence of dishes inside the treating chamber  16 , to remove any micro-organisms in the spray arm assemblies  22 ,  24 ,  26 , spray arm supply conduit  37 , and/or the treating chamber  16 , or to clean any remaining food soil in the treating chamber  16  that may have left from the previous wash cycle. 
     At  110 , the first portion of the wash liquid may be supplied from the reuse tank  52  to the treating chamber  16 . The stored liquid may be supplied back to the treating chamber  16  by gravity using outlet conduit  51  and control valve  56 . At  112 , the first portion of the wash liquid may be recirculated through the treating chamber similarly to the recirculation of the liquid at  408 . At  414 , when the recirculation ceases, the wash liquid having food soils, stains, or other impurities may be removed from the treating chamber  16 . More specifically, the wash liquid may be drained from the sump  30  by the drain pump  36 , with the control valve  63  actuated to direct the output of the drain pump  36  down the drain conduit  62 . It is further contemplated that after the recirculating of the first portion at least some of the wash liquid may be stored in the reuse tank  52 . 
     Regardless of the type of detergent dispenser  21  and the timing, it is contemplated that an amount of detergent for a single dose wash phase may be dispensed. Further, the first supply of liquid at  404  may include supplying an amount of liquid greater than a volume for a single dose wash phase, resulting in the wash liquid having a concentration of detergent less a single wash phase. In such an instance, the volume of the second portion may be a volume for a single dose wash phase. The volume of the first portion may also be a volume for a single dose wash phase. 
     It will be understood that the method  100  illustrated is merely for illustrative purposes. For example, the sequence of steps depicted is for illustrative purposes only, and is not meant to limit the method  100  in any way as it is understood that the steps may proceed in a different logical order or additional or intervening steps may be included without detracting from the embodiment of the invention. For example, at least some of the second portion of the wash liquid may be removed from the treating chamber  16  prior to the supplying of the first portion. Further, all of the second portion of the wash liquid may be removed from the treating chamber  16  prior to the supplying of the first portion. Alternatively, the first portion can be added to the second portion and the combined first and second portions can be recirculated. 
     A second amount of liquid may also be supplied to the treating chamber  16 , such as water from the household supply, until the combined volume of the supplied first portion and the second amount is sufficient for a single wash phase. A third amount of liquid may also be supplied to the treating chamber  16 , such as water from the household supply. Such a third supplying of water may form a rinse liquid in the treating chamber  16 . The rinse liquid may then be recirculated to rinse the dishes. The rinse liquid may then be drained or a portion of the rinse liquid may be stored in the reuse tank  52 . 
       FIG. 4  illustrates a dishwasher  200  according to a third embodiment. The third embodiment is similar to the first embodiment; therefore, like parts will be identified with like numerals increased by 200, with it being understood that the description of the like parts of the first embodiment applies to the fifth embodiment, unless otherwise noted. 
     One difference between the dishwasher  10  and the dishwasher  200  is that another or second reuse tank  253  is included in the dishwasher  200 . The second reuse tank  253  may also be used for storing liquid captured during one or more phases/steps of a wash cycle for later use in the current wash cycle and/or a subsequent wash cycle. The second reuse tank  253 , much like the first reuse tank  252 , may be fluidly coupled to the recirculation pump  234  by a reuse tank supply conduit  250  so that liquid from the sump  230  may be supplied to the reuse tank  252 . The control valve  248  may control the liquid from the recirculation pump  234  to the spray arm supply conduit  237 , the reuse tank supply conduit  250  that leads to the first reuse tank  252 , or the reuse supply tank conduit  257  leading to the second reuse tank  253 . The reuse tank  253  may also be fluidly coupled to the sump  230  by an outlet conduit  254  such that liquid in the reuse tank  253  may be supplied to the sump  230  for subsequent use. A control valve  255  is provided in the outlet conduit  254  to control the supply of liquid from the reuse tank  253  to the sump  230 . Although not illustrated a supply conduit may fluidly couple the reuse tank  253  to the drain pump  236  and a control valve may be provided to control the flow of liquid from the drain pump  236  to the drain conduit  262 , the first reuse tank  252  or the second reuse tank  253 . A heater  273 , a thermistor  269 , and a pH sensor  267  may be operably coupled to or included in the reuse tank  253  and operably coupled to the controller  240 . Additional sensors may be operably coupled to the reuse tank  253  to allow the controller  240  to monitor the characteristics of liquid in the reuse tank  253 . 
     It is contemplated that the dishwasher  200  may be operated much like the dishwasher  10 . For example, the dishwasher  200  may also be operated to carry out the method  100 . Either the first reuse tank  252  or the second reuse tank  253  may be used to store the first portion of the wash liquid while the second portion of the wash liquid is being used in the treating chamber  216 . Further, it is contemplated that there may also be a second supplying of liquid to the treating chamber  216 , such as water from the household supply, until the combined volume of the supplied first portion and the second supplying is sufficient for a single wash phase. There may also be a third supplying liquid to the treating chamber  216 , such as water from the household supply. Such a third supplying of water may form a rinse liquid in the treating chamber  216 . The rinse liquid may then be recirculated to rinse the dishes. The rinse liquid may then be drained or a portion of the rinse liquid may be stored in the first reuse tank  252  or the second reuse tank  253 . Alternatively, a portion of the rinse liquid may be stored in the second reuse tank  253  before recirculation of the rinse liquid. It is contemplated that at least one of the first and second supplying liquid comprises supplying liquid from the another reuse tank  253 . It is also contemplated that removing the wash liquid from the treating chamber  216  comprises storing at least some of the wash liquid in the first reuse tank or the another reuse tank  253 . 
     The embodiments of the invention described herein provide methods for operating a dishwasher fluidly coupled to at least one reuse tank. The methods of the invention can advantageously be used when the user may need to save water or any other liquid resources provided to the dishwasher. Further, by selectively storing wash liquid that includes detergent in the reuse tank, the reuse tank may be cleaned by the wash liquid. That is, the wash liquid with the detergent therein may be allowed to sit in the reuse tank while the other portion is being used, which may aid in keep the reuse tank clean. Further, the wash liquid may then be used in the treating chamber in as a second wash of relatively clean wash liquid. Further, if cold liquid is supplied to the treating chamber and then stored in the reuse tank it may be heated, either by ambient air or by a heater in the reuse tank before being supplied to the treating chamber. 
     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. 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.