Method of operating a dishwasher

A method for removing moisture from moist air in an appliance, such as a treating chamber of a dishwasher, wherein a drying system includes a condensing system and heat exchange systems that enhance condensation with both ambient air and cold water. The method includes storing cold water for use during a cycle of operation; recirculating the moist air in the treating chamber through a condenser; during the recirculating, flowing ambient air over the condenser; and during the recirculating and after the flowing ambient air, flowing the cold water over the condenser.

BACKGROUND

Dishwashers can include a drying system for drying dishes in a treating chamber of the dishwasher. Such drying systems can rely on a static dry, in which air from the exterior of the dishwasher flows into the treating chamber to replace some of the moist air, reducing overall humidity of the treating chamber which aids in the evaporation of moisture from the dishes. A condenser system, through which the air in the treating chamber is circulated through a condenser, can be used to remove the moisture in the air by condensation. Condensing systems are typically operated as either a closed loop system, where they do not introduce ambient air, or an open loop system, where they do introduce ambient air.

BRIEF DESCRIPTION

In one aspect, the disclosure relates to a method for removing moisture from moist air in an appliance, such as a treating chamber of a dishwasher, wherein a drying system includes a condensing system and heat exchange systems that enhance condensation with both ambient air and cold water. The method includes storing cold water for use during a cycle of operation; recirculating the moist air in the treating chamber through a condenser; during the recirculating, flowing ambient air over the condenser; and during the recirculating and after the flowing ambient air, flowing the cold water over the condenser.

DESCRIPTION

The aspects of the present disclosure are generally directed toward a method for removing moisture from moist air such that drying time of dishes in a dishwasher is reduced. The method includes a drying system having a condensing system, an ambient air heat exchange system, and a cold water heat exchange system that enhance condensation in the condenser. Both ambient air and cold water heat exchanger systems can increase the temperature differential between the wall of the condenser and the moist air. The ambient air and cold water can be used simultaneously or sequentially, with the sequential application providing the greater overall benefit as the process is currently understood. The method can also optionally include one or both of heating the moist air or adding ambient air to the moist air to increase the rate of condensation or evaporation of liquid in the treating chamber into the moist air.

InFIG. 1, an automated dishwasher10according to an aspect of the present disclosure is illustrated. A chassis12can define an interior of the dishwasher10and can include a frame, with or without panels mounted to the frame. An open-faced tub14can be provided within the chassis12and can at least partially define a treating chamber16, having an open face, for washing dishes. A door assembly18can be movably mounted to the dishwasher10for movement between opened and closed positions to selectively open and close the open face of the tub14. Thus, the door assembly18provides accessibility to the treating chamber16for the loading and unloading of dishes or other washable items.

It should be appreciated that the door assembly18can be secured to the lower front edge of the chassis12or to the lower front edge of the tub14via a hinge assembly (not shown) configured to pivot the door assembly18. When the door assembly18is closed, user access to the treating chamber16can be prevented, whereas user access to the treating chamber16can be permitted when the door assembly18is open.

Dish holders, illustrated in the form of upper and lower dish racks26,28, are located within the treating chamber16and receive dishes for washing. The upper and lower racks26,28are typically mounted for slidable movement in and out of the treating chamber16for ease of loading and unloading. Other dish holders can be provided, such as a silverware basket. As used in this description, the term “dish(es)” is intended to be generic to any item, single or plural, that can be treated in the dishwasher10, including, without limitation, dishes, plates, pots, bowls, pans, glassware, and silverware.

A spray system is provided for spraying liquid in the treating chamber16and is provided in the form of a first lower spray assembly34, a second lower spray assembly36, a rotating mid-level spray arm assembly38, and/or an upper spray arm assembly40. Upper spray arm assembly40, mid-level rotatable sprayer38and lower rotatable sprayer34are located, respectively, above the upper rack26, beneath the upper rack26, and beneath the lower rack28and are illustrated as rotating spray arms. The second lower spray assembly36is illustrated as being located adjacent the lower dish rack28toward the rear of the treating chamber16. The second lower spray assembly36is illustrated as including a vertically oriented distribution header or spray manifold44. 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 recirculation system is provided for recirculating liquid from the treating chamber16to the spray system. The recirculation system can include a sump30and a pump assembly31. The sump30collects the liquid sprayed in the treating chamber16and can be formed by a sloped or recess portion of a bottom wall of the tub14. The pump assembly31can include both a drain pump32and one or more recirculation pumps33. The drain pump32can draw liquid from the sump30and pump the liquid out of the dishwasher10to a household drain line (not shown). The recirculation pump33can draw liquid from the sump30and the liquid can be simultaneously or selectively pumped through a supply tube42to each of the assemblies34,36,38,40for selective spraying. While not shown, a liquid supply system can include a water supply conduit coupled with a household water supply108for supplying water to the treating chamber16. The household water supply108can include a household cold water supply, household hot water supply, or a mixture as desired.

A heating system including a heating element46can be located within the sump30for heating the liquid contained in the sump30.

A controller50can also be included in the dishwasher10, which can be operably coupled with various components of the dishwasher10to implement a cycle of operation. The controller50can be located within the door assembly18as illustrated, or it can alternatively be located somewhere within the chassis12. The controller50can also be operably coupled with a control panel or user interface56for receiving user-selected inputs and communicating information to the user. The user interface56can include operational controls such as dials, lights, switches, and displays enabling a user to input commands, such as a cycle of operation, to the controller50and receive information.

As illustrated schematically inFIG. 2, the controller50can be coupled with the heating element46for heating the wash liquid during a cycle of operation, the drain pump32for draining liquid from the treating chamber16, and the recirculation pump33for recirculating the wash liquid during the cycle of operation. The controller50can be provided with a memory52and a central processing unit (CPU)54. The memory52can be used for storing control software that can be executed by the CPU54in completing a cycle of operation using the dishwasher10and any additional software. For example, the memory52can store one or more pre-programmed cycles of operation that can be selected by a user and completed by the dishwasher10. The controller50can also receive input from one or more sensors57. Non-limiting examples of sensors that can be communicably coupled with the controller50include a temperature sensor, humidity sensor, and turbidity sensor to determine the soil load associated with a selected grouping of dishes, such as the dishes associated with a particular area of the treating chamber16.

FIG. 3is a schematic front view of the dishwasher10fromFIG. 1having the controller50ofFIG. 2. A drying system60can be provided for removing moisture from the treating chamber16during a drying cycle of the dishwasher10. The drying system60includes a condensing system70, an ambient air heat exchange system80, and a cold water heat exchange system90. The condensing system70is fluidly coupled to the treating chamber16such that moist air in the treating chamber16is recirculated through the condensing system70to condense liquid from the moist air and thereby dry the contents of the treating chamber16. The ambient air heat exchange system80flows ambient air over at least a portion of the condensing system70to increase the temperature differential between the condensing system70and the moist air to increase the rate of condensing. Similarly, the cold water heat exchange system90flows cold water over at least a portion of the condensing system70or the ambient air heat exchange system80to also increase the temperature differential between the condensing system70and the moist air to increase the rate of condensing.

The condensing system70includes a condenser72with a supply segment74fluidly coupled to the treating chamber16upstream of the condenser72and a return segment78fluidly coupled to the treating chamber16downstream of the condenser72. A fan62has a first stage64fluidly located within the return segment78. Operation of the fan62results in moist air being supplied to the condenser72through the supply segment74and returned to the treating chamber16through the return segment78. An additional fan or the fan62can also be a single stage. The additional fan or the fan62can be located upstream of the condenser72to move moist air from treating chamber16through condensing system70. When operated in these manners, the condensing system70is operated in a closed loop mode, without the addition of ambient air to the moist air.

The supply segment74includes an inlet opening75in fluid communication with a first portion of the treating chamber16. As shown herein, the inlet opening75can be formed in an upper wall76of the treating chamber16, although other locations are possible. The return segment78can include an outlet79, downstream of the first stage64, fluidly coupled to a lower portion of the treating chamber16, although other locations are possible.

Additionally, a heating element can be incorporated in one or more locations of the condensing system70to heat the moist air to increase the moisture carrying capacity of the moist air. The heating element can be the heating element46(FIG. 1) in the treating chamber16or it can be a dedicated heating element77located in the condensing system70. Optionally, a portion of the return segment78can pass through the motor compartment48where the heat generated by components in the motor compartment48can heat the moist air in the return segment78. A further option for heating the moist air and adding moisture carrying capacity can include a first controllable gate58in the return segment78to fluidly couple the motor compartment48to the return segment78. When the first controllable gate58is opened, warm air is drawn from the motor compartment48into the return segment78, which will supply a charge of warm, ambient air to the moist air flowing through the return segment78. By “warm, ambient air”, it is meant that the air is at a higher temperature than an ambient air84. The ambient air84includes, for example, air from the environment exterior of the dishwasher10or at least exterior of the treating chamber16. Typically, the air in the motor compartment48is approximately 4° C. warmer than the ambient air84, at least when the first controllable gate58is initially opened. The warm, ambient air is also normally dryer than the air in the treating chamber16, at least when the first controllable gate58is initially opened. When the first controllable gate58is opened and a charge of warm, ambient air is introduced into the return segment78, the condensing system70is operated in an open loop mode, until the first controllable gate58is closed, at which time, the condensing system70is returned to operating in a closed loop mode. Once the condensing system70is returned to operating in a closed loop mode, a mixture of moist air and warm, ambient air can flow through the condenser72of the condensing system70.

The ambient air heat exchange system80includes an ambient air heat exchanger82in thermal transfer relationship with the condenser72. The ambient air heat exchanger82is supplied ambient air84by an ambient air supply segment86and an exhaust segment88exhausts the ambient air downstream of the ambient air heat exchanger82to the surrounding environment, such as the ambient air within or exterior of the appliance. A second stage66of the fan62is fluidly coupled to the ambient air supply segment86to serially flow ambient air84through the ambient air supply segment86, ambient air heat exchanger82, and exhaust segment88. The ambient air heat exchanger82can guide ambient air84into direct contact to the outside of the condenser72. Alternatively, the ambient air heat exchanger82can guide ambient air84into a conduit (or any other form of pipe, tank, reservoir, etc.) that is in contact with the outside of the condenser72.

Optionally, a second controllable gate59can fluidly connect the ambient air heat exchange system80to the condensing system70. The second controllable gate59, when open, can provide a charge of ambient air84from the ambient air heat exchange system80into the condensing system70. When the second controllable gate59is opened, the condensing system70temporarily functions as an open loop condensing system, until the second controllable gate59is closed, then the condensing system70returns to closed loop operation. Once the condensing system70is returned to operating in a closed loop mode, a mixture of moist air and ambient air can flow through the condenser72of the condensing system70.

The cold water heat exchange system90includes a cold water heat exchanger92in thermal transfer relationship with the condenser72. The cold water heat exchanger92is downstream of a water supply segment94and upstream of a water outlet segment96. The water supply segment94couples to a household water supply108, which, for most homes, provides cold water at a temperature cooler than ambient air. In many homes the household cold water is around 20° C. or cooler. The cold water is supplied to the cold water heat exchanger92via the water supply segment94. Optionally, the cold water heat exchanger92can be upstream of the water supply segment94.

A water outlet segment96is fluidly coupled downstream to the cold water heat exchanger92and can further connect to a water channel98. The water channel98can be upstream of a household drain or can fluidly connect to the treating chamber16, such as the sump30(FIG. 1) in the treating chamber16. In addition, the cold water heat exchange system90or the water channel98can include or be coupled to any number of valves, conduit, or pumps normally found in the dishwasher. For example, the drain or recirculation pumps32,33can be coupled to the water channel98for use in pumping the cold water through the cold water heat exchanger92, instead of relying solely on the water pressure of the household water supply108.

Optionally, the water outlet segment96can fluidly connect to a water recirculation system110. The water recirculation system110can include a first water storage area112, a second water storage116, and a water recirculation segment114. The second water storage area116can be downstream of the water outlet segment96and upstream of the water channel98. The second water storage116area can also be connected to a water recirculation segment114which can be coupled to either the first water storage area112or the water supply segment94. Alternatively, the location of the connection of the water recirculation segment114can be at any point such that it can fluidly connect a location downstream of the cold water heat exchanger92to a location upstream of the cold water heat exchanger92. Further, the water recirculation system110can have any number of storage areas and is not restricting the location or number to that in the disclosure. In addition, the water recirculation system110can include or be coupled to any number of valves, conduit, or pumps.

The water recirculation system110can be used to recirculate cold water from the household water supply108through the cold water heat exchanger92. In this way, a charge of cold water can be supplied to the cold water heat exchange system90and recirculated through the cold water heat exchanger92. The recirculation of a charge of cold water has the benefit of using less water than a continuous supply of cold water, which is contemplated. The disadvantage of the recirculation of a charge of cold water is that the cold water becomes heated over time and creates less of a temperature differential with the moist air. The continuous supply of cold water has the benefit of greater cooling, with the disadvantage of more cold water consumed. One way to remediate the extra use of water for cooling is to store the cold water in one of the first or second water storage areas112,116for reuse later in the current cycle of operation or in a subsequent cycle of operation.

Optionally, the dishwasher10can further include a water regeneration system100for regenerating softening agents used by a water softener (not shown) and having a regeneration tank102in fluid communication with the treating chamber16. The regeneration tank102can include a vent104that is fluidly coupled with the ambient air84which permits excess air in the regeneration tank102or treating chamber16to be exhausted from the dishwasher10. The vent104can be pressure-activated or can be selectively closed by a controllable closure means, such as a valve106. Alternatively, if no regeneration system is provided with the dishwasher10, excess air in the treating chamber16can be exhausted from the dishwasher10via seals around the door assembly18(FIG. 1), which can be configured to open at a certain pressure differential between the treating chamber16and the environment, or other openings in the treating chamber16or the chassis12.

FIG. 4illustrates a method for removing moisture from moist air200within the treating chamber16of the dishwasher10. The method200includes the recirculation of moist air at201through the condensing system70, demonstrated by air recirculation arrows63inFIG. 3. Other aspects of the method for removing moisture from moist air200include flowing ambient air84at202through the ambient air heat exchange system80and flowing cold water at203through the cold water heat exchange system90, wherein the ambient air heat exchanger82, the cold water heat exchanger92are in thermal contact with the condenser72of the condensing system70. The ambient air heat exchanger82and the cold water heat exchanger92help to precipitate moisture from the air in the condenser72. The method for removing moisture from moist air200can optionally include mixing moist air with warm, ambient air or ambient air84at204. The mixing of moist air with warm, ambient air or ambient air84at204can include, and is not limited to, the opening and closing of a first controllable gate58or a second controllable gate59. The moist air can also be heated without the addition of warm air.

In a typical cycle of operation, moist air is formed in the treating chamber16by a washing, rinsing, or sanitizing cycle. The method200can be used to remove moisture from moist air within a treating chamber16of a dishwasher10. At201the first stage64of the fan62recirculates air from the treating chamber16into the supply segment74, through the condenser72, and back to the treating chamber16via the return segment78. At202the second stage66of the fan62pulls ambient air84into the ambient air supply segment86, through the ambient air heat exchanger82, and discharges air through the exhaust segment88. The condenser72is in thermal contact with the ambient air heat exchanger82. Moisture is precipitated from the moist air. The condensed moisture drips down from the condenser72and back into the tub14, and can thereafter be drained or recirculated from or to the dishwasher10.

In203, the second stage66of the fan62ceases to pull in ambient air84and cold water from the household water supply108flows through the water supply segment94to the cold water heat exchanger92. The cold water heat exchanger92is in thermal communication with the condenser72of the condensing system70. The cold water precipitates moisture from the moist air. The condensed moisture drips down from the condenser72and back into the tub14, and can thereafter be drained or recirculated from or to the dishwasher10. While not illustrated, valves or other components that interface with the second stage66of the fan62or the input of the household water supply108can be controlled by the controller50.

Downstream of the cold water heat exchanger92, the water outlet segment96can be fluidly connected to the water recirculation system110that can include a first or second water storage area112,116and recirculation segment114. Cold water can be recirculated through the cold water heat exchanger92several times using the recirculation segment114. Water can also accumulate in the first or second water storage areas112,116where it can be stored for reuse during a cycle or in a future cycle. The water outlet segment96and the first or second water storage areas112,116can also be coupled to a water channel98. The water channel98allows water to be drained or recirculated to the treating chamber16.

Step203demonstrates a reduction in energy consumption as the second stage66of the fan62can be turned off while cold water enhances condensation. The water used to enhance condensation is conserved through the storage of water for use in a future cycle or recirculation in the same cycle as previously described.

Another aspect of the present disclosure in203is the flow of cold water from the household water supply108into a reservoir, so that in the reservoir brings the cold water into direct contact with the outside wall of the condenser72or the ambient air heat exchanger82. The reservoir can be fluidly connected to the water outlet segment96.

Optional step204can occur multiple times during, between, or after any or all of steps201-203. In optional step204, the condensing system70can briefly or intermittently be opened. The second controllable gate59can be opened to allow a charge of ambient air84to mix with the air in the condensing system70. The ambient air84can have a lower humidity than the moist air, and can absorb some of the humidity. As a charge of ambient air84is introduced into the condensing system70, and thus into the treating chamber16, excess air in the treating chamber16can be exhausted via the vent104of the regeneration system100or through other openings in the treating chamber16. A charge of ambient air84can take place at one or more times before, during, or after a cycle of operation. Once the second controllable gate59is closed, the condensing system70returns to operating as a closed loop.

Optional step204can be used to increase the moisture carrying capacity of the moist air by introducing a charge of ambient air or warm, ambient air by the opening and closing of one or both of the first and second controllable gates58,59during, between, or after any of the steps201-203.

Another aspect of the present disclosure, the ambient air heat exchanger82and cold water heat exchanger92can each be implemented simultaneously or sequentially for one or multiple times in the drying cycle47.

FIG. 5illustrates a specific implementation of the present disclosure; a method for removing moisture from moist air300within the treating chamber16of the dishwasher10. The method for removing moisture from moist air300includes a recirculation of moist air at301through the condensing system70. Similar to201, at302the recirculating air in the condenser72of the condensing system70comes into thermal contact with the ambient air heat exchanger82. The recirculation of moist air at301and flow of ambient air at302continue until a threshold is satisfied at303. The threshold could be at least one of, but not limited to: a time, a moisture content of the moist air, or a temperature difference between the moist air and the ambient air. The testing for a threshold could reflect efficiency by measuring an air temperature difference between the moist air in the condensing system70and the ambient air in the ambient air heat exchange system80. At the beginning of a drying cycle, the moist air can have a temperature of approximately 45-68 C. As the temperature differential decreases between the moist air within the treating chamber16and the ambient air84, the efficiency of the condenser72also decreases. To take appropriate measurements at303one or more sensors57can be coupled to a controller50to obtain input to establish if a predetermined threshold is satisfied.

Once the at least one threshold is satisfied at303, recirculation of moist air continues at301, flowing ambient air ceases, and a flowing of cold water begins at304from the household water supply108through a cold water heat exchange system90. The cold water heat exchanger92of the cold water heat exchange system90is thermal contact with the condenser72of the condensing system70. The recirculation of moist air at301and the flowing of cold water at304continues until a threshold is satisfied at305for at least one of, and not limited to: a time, a moisture content of the air, or a temperature difference between the moist air and the cold water. The efficiency of the condensation depends on a temperature differential between the moist air in the condenser72and the cold water in the cold water heat exchanger92. Cold water can enter the dishwasher10at a temperature of 20° C. or less, increasing efficiency and reducing the length of time needed to dry the dishes in the treating chamber16. At305one or more sensors57coupled to a controller50can provide input to establish if a predetermined threshold is satisfied. If satisfied; the method can end at307.

Optionally at306, a charge occurs of warm, ambient air or ambient air into the recirculated moist air. Optional set306can occur at any time or at multiple times during the method for removing moisture from moist air300. The charge of warm, ambient air or ambient air at306can include, and is not limited to, the opening and closing of a first or second controllable gate58,59.

FIG. 6illustrates a perspective view of a dishwasher10in accordance with various aspects described herein with a specific implementation of a condensing system170, ambient air heat exchange system180, and cold water heat exchange system190, which operate in the same manner as previously described. The condensing system170includes a serpentine condenser172positioned inside a tank400formed on the side of the dishwasher10. The tank400can function as both an ambient air heat exchanger and a cold water heat exchanger. When used as an ambient air heat exchanger, ambient air84flows through the tank400, where the ambient air84comes into direct thermal contact with the serpentine condenser172. When used as a cold water heat exchanger, cold water is flowed into or through the tank400, where the cold water comes into direct thermal contact with the serpentine condenser172.

The methods200,300disclosed herein reduces the moisture in moist air of the treating chamber16of a dishwasher10. One advantage that can be realized is the utilization of both ambient air84at202,302and cold water at203,304to enhance condensation. An improvement in the efficiency of condensation will reduce drying time as well as the overall cycle time of the dishwasher10. Reducing drying time and cycle time also reduces energy consumption.

Another advantage that can be realized in the aspects of the present disclosure is the possibility that ambient air84is mixed with moist air at204,306to reduce overall moisture level. A reduction in moisture level can reduce drying time.

Another advantage that can be realized in the aspects of the present disclosure is the possibility that a charge of warm, ambient air from the first controllable gate58is mixed with moist air at204,306to reduce overall moisture level and increase the efficiency of the drying system60. Reduction in moisture level can reduce drying time or conserve energy.

Another advantage that can be realized in the aspects of the present disclosure is the possibility of water storage (112,116) for reuse of the flowing cold water. After flowing cold water (203,304) enhances condensation, the water can be stored in a water storage area (112,116) for reuse in the current or future cycle.

To the extent not already described, the different features and structures of the various aspects can be used in combination with each other as desired. That one feature cannot be illustrated in all of the aspects is not meant to be construed that it cannot be, but is done for brevity of description. Thus, the various features of the different aspects can be mixed and matched as desired to form new aspects, whether or not the new aspects are expressly described. Combinations or permutations of features described herein are covered by this disclosure.

This written description uses examples to disclose aspects of the disclosure, including the best mode, and also to enable any person skilled in the art to practice aspects of the disclosure, including making and using any devices or systems and performing any incorporated methods. While aspects of the disclosure have been specifically described in connection with certain specific details 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 disclosure, which is defined in the appended claims.