Dishwasher, a door assembly for the dishwasher, and an associated method for drying dishware

A dishwasher, a door assembly for the dishwasher and a method of drying the dishware in the dishwasher are provided. The dishwasher may include a sensor configured to measure the turbidity of the water in the dishwasher which is used to determine a wash load size. A control unit of the dishwasher may determine and control cycle times, temperatures, heating elements and a blower of the dishwasher based on the wash load size. The dishwasher may include a humidity level determination that may also be used by the control unit to control the operations of the dishwasher. The door assembly may include a duct configured to receive moisture-laden air creating during the drying cycle and encourage the condensation of the water from the air such that the water may be redirected back to the tub portion of the dishwasher and the dry air may be directed out of the dishwasher.

BACKGROUND

1. Field of the Invention

The present invention generally relates to dishwashers and, more particularly, to drying systems of dishwashers and associated methods thereto.

2. Description of Related Art

A dishwasher typically employs a series of cycles for cleaning dishware disposed within a tub portion of the dishwasher. One particular cycle, a drying cycle, is normally reserved as the final step in the cleaning process, the drying cycle is used to remove residual water from the dishware after the wash and rinse cycles are complete. Dishware is typically stacked vertically in upper and lower dish racks within the tub portion such that a substantial amount of the water used during a wash/rinse cycle runs off the dishware toward the bottom of the tub portion for collection in a sump. By such stacking, the amount of water collecting on the dishware is reduced or minimized (i.e., water is less likely to collect in the bowls, plates, cups, etc.).

Nevertheless, some residual water remains on the dishware (normally due to surface tension) and must be removed by employing the drying cycle. To that end, the dishwasher typically includes a heat source to warm the air that is forced into and circulated within the tub portion, wherein the heated air absorbs the residual water remaining on the dishware, resulting in humid air/moisture stagnating within the dishwasher to a point of saturation. At predetermined intervals, as usually determined when a humidity sensor measures a threshold level, the humid air is evacuated from within the tub portion, and the heat source again generates heated air to further dry the dishware, typically until the humidity sensor measures a predetermined moisture level signaling that further drying is not required. Often, these systems are somewhat ineffective in that the residual water is not completely removed from the dishware, and a “hand-dry” step is further needed to remove such residual water (e.g., a hand-towel is often used to remove residual water spots), much to the dissatisfaction of the user. Thus, the drying performance of such systems is limited, causing additional time to be needed once the dishwashing process has completed. That is, the user is not able to directly move the dishware from the dishwasher to cabinetry for storage due to the need for an additional drying step.

Accordingly, an improved drying system for a dishwasher and associated method may be desirable.

BRIEF SUMMARY

Embodiments of the present invention address the above by providing a method of drying dishware in a tub portion of a dishwasher, a dishwasher, and a door assembly for a dishwasher. For example, according to an embodiment, a method of drying dishware in a tub portion of a dishwasher is provided. The method may include determining a wash load size of dishware disposed in the tub portion; determining at least one of a rinse water temperature and a cycle time duration based on the wash load size; rinsing the dishware in a tub portion, with the water at the rinse water temperature for the cycle time duration; determining a humidity level in the tub portion; cyclically actuating at least one heating element based, at least partially, on the humidity level, to heat air within and promote vaporization of water disposed on the dishware; cyclically actuating a blower based, at least partially, on the humidity level to direct the heated air and vaporized water toward a duct associated with the tub portion; condensing the vaporized water through interaction thereof with at least one condensing surface disposed within the duct, as the air and vaporized water are directed along the duct; and directing the condensed water back into the tub portion and directing the air out of the tub portion.

In other embodiments, the method may further include determining a turbidity of water used in a washing cycle. The determination of the wash load size may be based, at least partially, on the determined turbidity. The method may also include determining the humidity level in the duct and ceasing the cyclical actuation of the at least one heating element and the blower upon determining that the humidity level in one of the tub portion and the duct is below a threshold. The condensation of the vaporized water may include directing the air and the vaporized water along a tortuous path defined by the duct to promote the interaction of the vaporized water with the at least one condensing surface disposed within the duct.

In another embodiment, a dishwasher is provided. The dishwasher may a tub portion adapted to hold dishware, a sensor configured to measure a turbidity of water in the tub portion, and a control unit. The control unit may be in communication with the first sensor and configured to determine a wash load size associated with the dishware within the tub portion based, at least partially, on the turbidity. The control unit may be further configured to determine at least one of a rinse water temperature and a cycle time duration based, at least partially, on the wash load size.

The dishwasher may further include a heating element, a blower and a duct. The heating element is proximate a bottom of the tub portion and configured to heat air inside the tub portion during a drying cycle. The heat causes the air to rise toward a top of the tub portion and collect vaporized water from the dishware. The blower is configured to direct the air and vaporized water into the duct having an inlet proximate the top of the tub portion. The duct is configured to receive the air and the vaporized water.

The duct may extend from the inlet to an outlet and be configured to facilitate condensation of the vaporized water as the air and vaporized water are directed travels from the inlet toward the outlet. In some embodiments, the duct may define a tortuous path extending at least partially between the inlet and the outlet. The tortuous path is configured to facilitate the condensation of the vaporized water as the air and vaporized water are directed from the inlet toward the outlet. The duct may also define a drain opening configured to direct the condensed water back toward the tub portion and the outlet may be configured to direct the air outside of the tub portion. For example, the drain opening may be disposed about a lowest, gravity-fed portion of the tortuous path. The duct may also include at least one condensing surface configured to facilitate condensation of the vaporized water upon interaction therewith as the air and vaporized water are directed from the inlet toward the outlet.

Another embodiment provides a door assembly operably engaged with and configured to provide access to the tub portion and a housing. The duct may extend between an outer wall and an inner wall of the door assembly. The housing may extend between the inlet of the duct and an inner facing side of the inner wall such that the inlet of the duct is in communication with the tub portion through the housing. In some embodiments, the blower is remotely disposed with respect to the housing.

Referring back to the door assembly, in an embodiment, the inner and outer walls define a plane extending therebetween. The duct may extend parallel to the plane and further include a fluid containment element disposed on opposite sides of the drain opening. The fluid containment element may extend perpendicularly to the plane, from a portion of the duct disposed adjacent to the outer wall and toward an opposing portion of the duct disposed adjacent to the inner wall, so as to retain fluid therebetween and to direct the fluid toward the drain opening, when the inner and outer walls are horizontally disposed with the door assembly in an open position.

In yet another embodiment, the dishwasher further includes a second sensor configured to measure a humidity level. The control unit may be in communication with the second sensor and may be configured to selectively actuate and de-actuate at least one of the heating element and the blower, at least partially based on the humidity level. The second sensor may be disposed in the duct.

FIG. 1illustrates an example of a dishwasher10that may benefit from various embodiments of the present invention. The dishwasher10may include a tub portion12(partly broken away inFIG. 1to show internal details) having a door assembly50and a plurality of walls13that together form an enclosure in which dishes, utensils, and other dishware may be placed for washing. The tub portion12may also define a forward access opening, generally designated as16. As known in the art, the dishwasher10may also include slidable lower and upper racks (not shown) for holding the dishes, utensils, and other dishware to be washed. The tub portion12may define a sump, generally designated as14, in which wash water or rinse water is collected, typically under the influence of gravity. The wash/rinse water may be pumped by a pump15out of the sump14to various spray arms20mounted in the interior of the tub portion12for spraying the wash/rinse water, under pressure, onto the dishes, utensils, and other dishware contained therein. The pump15and/or other operational components (e.g., circulation pump, drain pump, water valve) may be housed, disposed, or otherwise positioned within a base portion/component22positioned beneath the tub portion12, wherein the base portion22receives and supports a lower end, generally designated as18of the tub portion12. In some instances, the base portion22may be a separate component with respect to the tub portion12, such as, for example, a molded polymer component, while in other instances the base portion22may be integral with the tub portion12such that the side walls forming the tub portion12also at least partially form the base portion22.

The door assembly50may be pivotably engaged with the tub portion12about the lower end18thereof so as to selectively permit access to the interior of the tub portion12. That is, a lower edge26of the door assembly50may be pivotably engaged (e.g., hinged) with the lower end18of the tub portion12such that the door assembly50is pivotable about the lower edge26thereof to cover and seal the forward access opening16in a closed position when the dishwasher10is in operation, and to provide access to the interior of the tub portion12through the forward access opening16when the door assembly50is pivoted from the closed position to an opened position. In some instances, the door assembly50may comprise an inner wall60and an outer wall70. The door assembly50may include a handle member24disposed on an outer surface72of the outer wall70, to provide the user with a grasping portion.

Embodiments of the present invention generally relate to a drying system of the dishwasher configured to help remove moisture from the dishwasher during a drying cycle so as to help dry the dishware disposed in the tub portion. According to an embodiment of the present invention, the drying system may be generally disposed within the door assembly of the dishwasher. For example and as illustrated inFIGS. 2 through 5, the drying system200may include a blower210(e.g., a centrifugal blower) and a duct220, both of which may be positioned in the door assembly of the dishwasher.

More specifically, the blower210may positioned proximate the top of the door assembly250such that an inlet212of the blower is disposed on an interior wall or other interior portion of the door assembly250. In such a position, the blower210is configured to draw or force air, such as the moist air during a drying cycle, from the tub portion toward the duct220inside of the door assembly250. The inlet212may include a plurality of louvered fins (not visible inFIGS. 2 through 4) forming a barrier to minimize water (from spray or in the form of airborne droplets) from being pulled into the blower210. As discussed further herein, in addition to the blower210, the dishwasher may include a heating device or element (not visible inFIGS. 2 through 4) configured to heat the air within the tub portion. Heating the air causes the air to rise toward the upper end of the tub portion and toward the blower210.

The duct220may extend from an inlet end222to an outlet end224in the door assembly between an inner wall and an outer wall of the door assembly. The inlet end222of the duct may be communication with the blower210such that as the moist air is drawn out of the tub portion by the blower210, the moist air is directed substantially into the inlet end222of the duct.FIGS. 2 and 3illustrate an example of the inlet end222being in communication with the blower210. In particular,FIG. 2illustrates the inner facing side of the interior wall of the door assembly250in which the inlet212of the blower is visible.FIGS. 2 and 3illustrate the outer facing side of the interior wall of the door assembly250with the majority of the duct220being visible and a portion of the inlet end222of the duct removed to allow the blower210to be visible for illustration purposes only.

The duct220may include a plurality of ribs228configured to interact with the air as the air is drawn in from the tub portion by the blower210. As the air passes through the duct220, the ribs228create multiple surfaces for the air to interact with so as to remove moisture from the air. As such, the moist air condenses as it navigates through the ribs228of the duct220. Proximate the outlet end224, the duct220may be in communication with a drain opening226disposed proximate the bottom of the door assembly250. The drain opening may be disposed on the interior wall or other interior portion of the door assembly250such that as the water condenses due to the ribs228, the water flows through the duct220, out of the drain opening, and into the bottom of the tub portion to be collected in the sump of the dishwasher. As the water is drained through the drain opening226, the resultant “drier” air flowing through the duct220is directed to the outlet end224of the duct which may disposed on the outer wall or other outer portion of the door assembly250, e.g., as illustrated inFIG. 5, such that the drier air (i.e., drier as a result from the condensation process) exits the dishwasher.

In another embodiment, a blower610may be disposed remotely from the duct620. As an example and as illustrated inFIGS. 6 through 10, the blower610may be disposed in an upper wall604of the tub portion602and configured to draw air into the tub portion602from outside the dishwasher600. A heating device or element606, e.g., disposed in or proximate to the lower end of the tub portion602, heats the air within the tub portion602. As the air is heated, the air will rise to the upper end of the tub portion602collecting moisture along the way.

In at least some instances, these factors may combine to pressurize the air in the tub portion602. Once pressurized the air is directed toward and into a housing615of the drying system. The housing615may be positioned proximate the top of the door assembly650such that an inlet of the housing is disposed on an interior wall or other interior portion of the door assembly650and in communication with a duct620extending from an inlet end to an outlet end within the door assembly.

To facilitate the communication between the housing615and the duct620(i.e., the fluid transfer between the two), the housing615and the duct620may configured to connect together.FIG. 10provides an example of such a configuration in which the housing615includes a projection616configured to engage a side opening621of the duct and, thus, connecting the housing615and the duct620together.FIG. 11provides another example of such a configuration in which the housing1115includes a projection1116configured to engage a top opening1121of the duct and, thus, connecting the housing1115and the duct1120together.

As shown in bothFIGS. 10 and 11, the housing615,1115may include an inlet. The inlet may include a plurality of louvered fins617,1117forming a barrier to minimize water (from spray or in the form of airborne droplets) from being pulled into the housing615,1115.

Referring back to the duct620, the duct620may extend from an inlet end622to an outlet end624for example as illustrated inFIGS. 7 and 12. In general, the duct is configured to condense the moisture from the air and direct the condensed moisture back into the tub portion and/or direct the drier air outside the dishwasher. For example, as explained above, the duct may include a plurality of ribs to create multiple surfaces for the air to interact with so as to promote condensation.

Instead of or in addition to the ribs, the duct620may be configured to traverse or extend along a tortuous path, in the plane of the door assembly, at least partially between the inlet and outlet ends. As used herein, a “tortuous path” means that the path includes multiple bends or turns and changes in directions, e.g., as illustrated inFIGS. 7 and 12. In this manner, the moisture-laden air interacts more with the walls defining the duct620than it would if the duct took a more linear path. This increased interaction with the walls increases the amount of moisture from the air that is condensed as the air travels through the duct620.

The duct620may also include a drain port or opening626, as shown inFIG. 12. More specifically, about a lowest, gravity-fed portion of the tortuous duct620, the duct may define a drain opening or port configured to collect the condense moisture and direct the moisture back toward the bottom of the tub portion to be collected in the sump of the dishwasher.

The duct620may be further configured in a tortuous manner in a plane perpendicular to the plane of the door assembly650, e.g., as illustrated inFIGS. 13 and 14. In particular, and as illustrated, the duct620may further include one or more portions628varying from the path of the duct620, perpendicularly to the plane of the door assembly650. In some instances, e.g., the illustrated embodiment ofFIGS. 13 and 14, one such portion may be disposed on either side of the drain opening626defining a drain extension628. The orientation or direction of the drain extension628is intended to lead the water back into the tub portion602(e.g., in instances, where a user may spill water into the duct with the door in an open position, the orientation of the drain extension628is intended to lead the spill water back toward the tub portion602rather than outside the dishwasher).

Embodiments of the dishwasher1500may further include a control unit1550and one or more sensors, e.g., as shown as a block diagram inFIG. 15. The control unit1550may be configured to control, adjust, and/or synchronize one or more of the operations of the dishwasher, at least partially, based on information received from the sensors. The control unit may be embodied as a processor(s), coprocessor(s), a controller(s) or various other processing means or devices including, without limitation, integrated circuits. Examples of sensors include, without limitation, a turbidity sensor1570, a humidity sensor1580, and a temperature sensor1590. In general, a turbidity sensor is a device configured to measure the level of particulates (or simply referred to as the “dirtiness”) of water or other liquids. A humidity sensor is a device configured to measure the amount of moisture in or relative humidity of a medium such as air. And a temperature sensor is a device configured to measure the temperature of a medium such as air or water. As explained above, components of the dishwasher may include, without limitation, one or more heating elements1560, a blower1510, a spray arm1520, and a pump1515. The control unit1550may be in electrical communication with the one or more sensors1570,1580,1590such the control unit1550receives information, e.g., level of dirtiness, level of humidity, and temperature. Based on the received information, the control unit1550, which is in electrical communication with the components1510,1515,1520,1560of the dishwasher, may send commands to one or more of the components1510,1515,1520,1560, e.g., turn on or off and/or increase or decrease an output. In addition to or instead of the sensors, the control unit1550may receive instructions or other information from an input device1552, such as a control panel on the front side of the door assembly. The dishwasher1500may further include one or more memory elements1554for storing instructions (e.g., a software program) for the control unit1550.

FIG. 16illustrates an example of a method of drying dishware in a dishwasher that may be implemented by one or more of the embodiments disclosed herein. The method includes determining a wash load size of the dishwasher1600. In general, the wash load size provides an approximation of the amount of soils that need to be removed from the dishware. The wash load size may be relatively large due to the amount of dishware (e.g., large number of plates and bowls) and/or the amount of soil that is on the dishware (e.g., the relative dirtiness of the dishware). Rather than provide an approximate value to the wash load size, embodiments may employ relative sizes, such as, small, medium, and large. According to an embodiment, the wash load size may be determined solely or at least partially through the measurement of the dirtiness or turbidity of the water in the tub portion or the sump. In general, more “soils” in the water indicates a larger wash load size. The turbidity of the water may be measured by a turbidity sensor, as explained above, either during a wash or rinse cycle. The location of the turbidity sensor may vary, e.g., the sensor may be in the sump or bottom portion of the tub portion. In another embodiment, instead or in addition to the turbidity sensor, the determination of the wash load size may rely on an input from an operator. For example, an operator may input a wash load size through an input device.

The method may further include heating water to a rinse water temperature. For example, the heated water may come from an external source such as, e.g., the water system of a house. The water may be heated as part of the water system, e.g., an external water heater, and/or be heated by one or more heating elements in the dishwasher. Rinsing the dishware with the heated water will heat the dishware to a dishware temperature based on the rinse water temperature, the wash load size, and the rinse cycle time. In general, the rinse water temperature has a direct relationship with the dishware temperature, i.e., the higher the rinse water temperature then the higher the dishware temperature. The wash load size provides an indication of the total thermal mass of the dishware. A greater wash load size generally indicates a greater thermal mass. The thermal mass of the dishware provides an indication of the time it may take to heat the dishware to a desired dishware temperature in that a larger thermal mass takes longer to heat then a small thermal mass. Therefore, it is believed that determining the wash load size helps to determine a preferred water rinse temperature and/or a preferred cycle time needed to obtain a particular dishware temperature and to effectively clean the dishware and/or effectively sanitize the dishware. In other words, the method may include determining at least one of a rinse water temperature and a cycle time based on the wash load size in order to obtain a preferred dishware temperature1610and rinsing the dishware in the tub portion of the dishwasher with the water at the rinse water temperature and for the duration of the cycle time1620. In some embodiments, the final rinse water temperature may be limited or fixed due to the limitations of the external water and heating elements of the dishwasher or the water system and, thus, in some embodiments, only the cycle time may be adjusted according to the wash load size. It should be understood that the determination of the preferred rinse water temperature and/or the cycle time based on the wash load size may apply to one or both of the wash and rinse cycles.

As illustrated inFIG. 16, the method may also include determining a humidity level in the dishwasher1630. According to an embodiment, the humidity is measured by a humidity sensor located in the duct (e.g., as illustrated inFIG. 12, wherein the humidity sensor is represented by1580). It is believed that inside the duct is a preferred location for the humidity sensor because the environment inside the duct has a relatively low level of water or liquid compared to the tub portion and sump. It is also believed that the level of humidity in the duct provides an indication of how dry the dishware is in the tub portion. For example, after the cleaning and rinse cycles, the surfaces of the dishware may be wet. Therefore, as explained herein, as the air is heated during the dry cycle, the water on the surfaces of the dishware may start to evaporate or vaporize into the air in the tub portion such that as the air and vaporized water enters in the duct, the measured humidity will be relatively high. As the dishware starts to dry, less and less water will be vaporized into the air and, thus, the air entering the duct will contain less vaporized water and the measured humidity will be less. Once the humidity level reaches a certain minimal level, the dishware may be considered dry and the drying cycle may stop, i.e., the method may further include ending the pulsing or cyclically actuating of the one or more heating elements and the blower upon the humidity level reaching a minimum level as discussed further herein.

As part of the drying cycle, the method may include cyclically actuating one or more heating elements on and off based, at least partially, on the humidity level to heat the air in the tub portion and promote vaporization of water from the dishware to the air1650and pulsing a blower on and off based, at least partially, on the humidity level to help direct the air and the vaporized water in the air to a duct1660. “Pulsing” or “cyclically actuating” generally means selectively activating or cycling the blower and the heating elements rather than constantly having these components on. The humidity level and, in some embodiments, the determined wash load size, may be used, for example, by the control unit to determine the preferred cycles or activation periods for the components. For example, the pulsing of the heating elements is configured to provide the requisite or optimal heat to a tub portion of the dishwasher in order to evaporate or vaporize water residual left on the dishware, i.e., to help dry the dishware, while conserving energy compared to if the heating elements were constantly on. The pulsing of the blower is configured to provide additional air from outside the dishware in order to help pressure the tub portion or to otherwise encourage the air containing the water vapor toward the duct.

The method may further include condensing the vaporized water through the interaction of the vaporized water and one or more surfaces inside the duct (e.g., due to a tortuous path of the duct and/or fins or ribs in the duct) as the air travels through the duct1660. The method may further include directing the condensed water back into the tub portion and directing the drier air resulting from the condensation process out of the dishwasher1670.

The above embodiment, through the determination of wash load size and the relative humidity or level of humidity in the duct, allows the control unit to optimize the drying cycle in that it can control the operations of the blower and the heating elements selectively and thereby conserve energy while drying the dishware in the tub portion.