Patent Application
20250072712
Dishwashers are used in many single-family and multi-family residential applications to clean dishes, silverware, cutlery, cups, glasses, pots, pans, etc. (collectively referred to herein as “utensils”). Drying utensils at the end of a wash cycle, however, can be time consuming, and can lead to extended cycle times.
One manner of decreasing the drying time in a dishwasher is to introduce ambient air into a wash tub to mix with water vapor present in the wash tub, and then exhausting the resulting humid air back into the surrounding environment. In many instances, a fan may be used to drive the air flow through the wash tub. In addition, in some instances, the ambient air may also be heated prior to introduction into the wash tub, as hotter air has a greater capacity to retain water vapor.
The rate at which air is circulated in this manner, however, is typically limited due to the relatively high humidity of the air being exhausted from the wash tub. In particular, if the dew point of the exhausted air is above the ambient room temperature, moisture in the exhausted air may undesirably condense on surfaces in the surrounding environment. As a result, many dishwasher designs limit the air flow rate through the wash tub to reduce condensation, but doing so increases the amount of time required to appropriately dry the utensils at the end of the wash cycle.
Therefore, a need exists in the art for a manner of accelerating drying of utensils at the end of a wash cycle performed by a dishwasher, while also limiting condensation on or around the dishwasher.
The herein-described embodiments address these and other problems associated with the art by providing a dishwasher including a drying system that incorporates a mixing conduit that mixes air streams from an exhaust fan that draws humid air from a wash tub and a mixing fan that draws ambient air from the surrounding environment of the dishwasher to lower a dew point of the air that is exhausted by the dishwasher. In some instances, an additional inlet fan may be used to direct ambient air into the wash tub, and in some instances, the ambient air drawing into the mixing conduit by the mixing fan may be untreated.
Therefore, consistent with one aspect of the invention, a dishwasher may include a wash tub, at least one spray device disposed in the wash tub, a fluid supply configured to supply wash fluid to the at least one spray device, an air supply in fluid communication with the wash tub and configured to direct an inlet air stream into the wash tub, the air supply including an inlet fan in fluid communication with and upstream of the wash tub, an exhaust fan configured to draw a humid air stream from the wash tub from a position downstream of the wash tub, a mixing conduit including first and second inlets and an outlet, the first inlet of the mixing conduit in fluid communication with and downstream of the exhaust fan, and a mixing fan in fluid communication with and upstream of the second inlet of the mixing conduit and configured to direct an ambient air stream into the second inlet of the mixing conduit to mix ambient air with the humid air stream and thereby lower a dew point of the humid air stream exhausted from the outlet of the mixing conduit.
In some embodiments, the air supply further includes a heater configured to heat the inlet air stream. Also, in some embodiments, the ambient air stream directed into the second inlet of the mixing conduit is untreated. In addition, some embodiments may further include at least one environmental sensor configured to sense an environmental condition of air exhausted from the outlet of the mixing conduit.
Some embodiments may further include a controller coupled to the at least one environmental sensor, the inlet fan, the exhaust fan, and the mixing fan, the controller configured to vary a speed of the inlet fan, the exhaust fan and/or the mixing fan to maintain the dew point of the humid air stream exhausted from the outlet of the mixing conduit below a temperature of an ambient environment within which the dishwasher is installed. Further, in some embodiments, the at least one environmental sensor is configured to sense a temperature and/or a humidity of the humid air stream exhausted from the outlet of the mixing conduit. In some embodiments, the controller is configured to determine the temperature of the ambient environment using the at least one environmental sensor and prior to performing a drying operation with the inlet fan, the exhaust fan and the mixing fan. In addition, in some embodiments, the controller is configured to determine the temperature of the ambient environment by communicating with a thermostat disposed in the ambient environment. In some embodiments, the at least one environmental sensor includes a first environmental sensor configured to sense the temperature and/or the humidity of the humid air stream exhausted from the outlet of the mixing conduit and a second environmental sensor configured to sense the temperature of the ambient environment.
In addition, in some embodiments, the controller is configured to vary the speed of the inlet fan, the exhaust fan and/or the mixing fan to maintain the dew point of the humid air stream exhausted from the outlet of the mixing conduit below the temperature of the ambient environment by, in response to determining that the dew point of the humid air stream exhausted from the outlet of the mixing conduit exceeds the ambient temperature, increasing the mixing fan speed and/or decreasing the exhaust and/or inlet fan speeds to lower the dew point of the humid air stream exhausted from the outlet of the mixing conduit. Moreover, in some embodiments, the controller is configured to vary the speed of the inlet fan, the exhaust fan and/or the mixing fan to maintain the dew point of the humid air stream exhausted from the outlet of the mixing conduit below the temperature of the ambient environment by, in response to determining that the dew point of the humid air stream exhausted from the outlet of the mixing conduit is less than the ambient temperature, decreasing the mixing fan speed and/or increasing the exhaust and/or inlet fan speeds to increase the dew point of the humid air stream exhausted from the outlet of the mixing conduit.
Consistent with another aspect of the invention, a dishwasher may include a wash tub, at least one spray device disposed in the wash tub, a fluid supply configured to supply wash fluid to the at least one spray device, an air supply in fluid communication with the wash tub and configured to direct an inlet air stream into the wash tub, an exhaust fan configured to draw a humid air stream from the wash tub from a position downstream of the wash tub, a mixing conduit including first and second inlets and an outlet, the first inlet of the mixing conduit in fluid communication with and downstream of the exhaust fan, and a mixing fan in fluid communication with and upstream of the second inlet of the mixing conduit and configured to direct an untreated ambient air stream into the second inlet of the mixing conduit to mix untreated ambient air with the humid air stream and thereby lower a dew point of the humid air stream exhausted from the outlet of the mixing conduit.
In some embodiments, the air supply includes an inlet fan in fluid communication with and upstream of the wash tub, and a heater configured to heat the inlet air stream. Some embodiments may also include at least one environmental sensor configured to sense an environmental condition of air exhausted from the outlet of the mixing conduit. Some embodiments may further include a controller coupled to the at least one environmental sensor, the exhaust fan, and the mixing fan, the controller configured to vary a speed of the exhaust fan and/or the mixing fan to maintain the dew point of the humid air stream exhausted from the outlet of the mixing conduit below a temperature of an ambient environment within which the dishwasher is installed. In some embodiments, the at least one environmental sensor is configured to sense a temperature and/or a humidity of the humid air stream exhausted from the outlet of the mixing conduit. In addition, in some embodiments, the controller is configured to determine the temperature of the ambient environment using the at least one environmental sensor and prior to performing a drying operation with the exhaust fan and the mixing fan. In some embodiments, the at least one environmental sensor includes a first environmental sensor configured to sense the temperature and/or the humidity of the humid air stream exhausted from the outlet of the mixing conduit and a second environmental sensor configured to sense the temperature of the ambient environment.
Moreover, in some embodiments, the controller is configured to vary the speed of the exhaust fan and/or the mixing fan to maintain the dew point of the humid air stream exhausted from the outlet of the mixing conduit below the temperature of the ambient environment by, in response to determining that the dew point of the humid air stream exhausted from the outlet of the mixing conduit exceeds the ambient temperature, increasing the mixing fan speed and/or decreasing the exhaust fan speed to lower the dew point of the humid air stream exhausted from the outlet of the mixing conduit. Also, in some embodiments, the controller is configured to vary the speed of the exhaust fan and/or the mixing fan to maintain the dew point of the humid air stream exhausted from the outlet of the mixing conduit below the temperature of the ambient environment by, in response to determining that the dew point of the humid air stream exhausted from the outlet of the mixing conduit is less than the ambient temperature, decreasing the mixing fan speed and/or increasing the exhaust fan speed to increase the dew point of the humid air stream exhausted from the outlet of the mixing conduit.
These and other advantages and features, which characterize the invention, are set forth in the claims annexed hereto and forming a further part hereof. However, for a better understanding of the invention, and of the advantages and objectives attained through its use, reference should be made to the Drawings, and to the accompanying descriptive matter, in which there is described example embodiments of the invention. This summary is merely provided to introduce a selection of concepts that are further described below in the detailed description, and is not intended to identify key or essential features of the claimed subject matter, nor is it intended to be used as an aid in limiting the scope of the claimed subject matter.
Turning now to the drawings, wherein like numbers denote like parts throughout the several views,
Control over dishwasher 10 by a user is generally managed through a control panel 28 typically disposed on a top or front of door 12, and it will be appreciated that in different dishwasher designs, the control panel may include various types of input and/or output devices, including various knobs, buttons, lights, switches, textual and/or graphical displays, touch screens, etc. through which a user may configure one or more settings and start and stop a wash cycle.
The embodiments discussed hereinafter will focus on the implementation of the hereinafter-described techniques within a hinged-door dishwasher. However, it will be appreciated that the herein-described techniques may also be used in connection with other types of dishwashers in some embodiments. For example, the herein-described techniques may be used in commercial applications in some embodiments. Moreover, at least some of the herein-described techniques may be used in connection with other dishwasher configurations, including dishwashers utilizing sliding drawers.
Now turning to
As shown in
Controller 30 may also be coupled to a water heater 38 that heats fluids, a pump 40 that recirculates fluid within the wash tub by pumping fluid to the wash arms and other spray devices in the dishwasher, a drain valve 42 that is coupled to a drain to direct fluids out of the dishwasher, and a diverter 44 that controls the routing of pumped fluid to different wash arms and/or other sprayers during a wash cycle. In some embodiments, a single pump 40 may be used, and drain valve 42 may be configured to direct pumped fluid either to a drain or to the diverter 44 such that pump 40 is used both to drain fluid from the dishwasher and to recirculate fluid throughout the dishwasher during a wash cycle. In other embodiments, separate pumps may be used for draining the dishwasher and recirculating fluid. Diverter 44 in some embodiments may be a passive diverter that automatically sequences between different outlets, while in some embodiments diverter 44 may be a powered diverter that is controllable to route fluid to specific outlets on demand. Generally, pump 40 may be considered to be a fluid supply in some embodiments as pump 40 supplies a pressurized source of fluid to diverter 44 for distribution to one or more spray arms and/or sprayers.
Controller 30 may also be coupled to a dispenser 46 to trigger the dispensing of detergent and/or rinse agent into the wash tub at appropriate points during a wash cycle. Additional sensors 48 and actuators may also be used in some embodiments, including, for example, a temperature sensor to determine a wash fluid temperature, a door switch to determine when door 12 is latched, various turbidity or conductivity sensors, etc. Moreover, controller 30 may be coupled to a user interface 50 including various input/output devices such as knobs, dials, sliders, switches, buttons, lights, textual and/or graphics displays, touch screen displays, speakers, image capture devices, microphones, etc. for receiving input from and communicating with a user (e.g., at least partially disposed on control panel 28 of
Moreover, in some embodiments, at least a portion of controller 30 may be implemented externally from dishwasher 10, e.g., within a mobile device, a cloud computing environment, etc., such that at least a portion of the functionality described herein is implemented within the portion of the controller that is externally implemented. In some embodiments, controller 30 may operate under the control of an operating system and may execute or otherwise rely upon various computer software applications, components, programs, objects, modules, data structures, etc. In addition, controller 30 may also incorporate hardware logic to implement some or all of the functionality disclosed herein. Further, in some embodiments, the sequences of operations performed by controller 30 to implement the embodiments disclosed herein may be implemented using program code including one or more instructions that are resident at various times in various memory and storage devices, and that, when read and executed by one or more hardware-based processors, perform the operations embodying desired functionality. Moreover, in some embodiments, such program code may be distributed as a program product in a variety of forms, and that the invention applies equally regardless of the particular type of computer readable media used to actually carry out the distribution, including, for example, non-transitory computer readable storage media. In addition, it will be appreciated that the various operations described herein may be combined, split, reordered, reversed, varied, omitted, parallelized and/or supplemented with other techniques known in the art, and therefore, the invention is not limited to the particular sequences of operations described herein.
Numerous variations and modifications to the dishwasher illustrated in
As noted above, the drying systems of many dishwashers utilize fans to force air, which in some instances may also be heated, through a wash tub to accelerate drying. Fan speeds, however, are typically limited due to the high humidity inside the wash tub, which can lead to condensation on external surfaces on and/or proximate the dishwasher when the dew point of the exhausted air is above the ambient room temperature.
In embodiments consistent with the invention, however, a mixing conduit may be used to mix air streams from an exhaust fan that draws humid air from a wash tub and a mixing fan that draws ambient air from the surrounding environment of the dishwasher to lower a dew point of the air that is exhausted by the dishwasher, and thereby reduce the likelihood of condensation on external surfaces on and/or surrounding the dishwasher. For the purposes of this disclosure, ambient air generally refers to air that is obtained from the environment surrounding the dishwasher, and which is generally representative of the air within the room in which the dishwasher is installed. Inlet air may be considered to refer to air that is being supplied to a wash tub during a drying operation, while exhaust air may be considered to refer to air that is being drawn or exhausted from a wash tub, which at least during the early stages of a drying operation, also may be considered to be humid air containing water vapor collected from the wash tub. Mixed exhaust air, in turn, refers to air that is a mixture of humid exhaust air drawn from the wash tub and ambient air that has been mixed with the humid exhaust air within the mixing conduit, and exhausted into the environment surrounding the dishwasher.
As will become more apparent below, in some instances, an additional inlet fan may be used to direct ambient air into the wash tub as inlet air, and in some instances, the ambient air directed into the mixing conduit by the mixing fan may be untreated, i.e., the ambient air is supplied to the mixing conduit without first being treated to control its temperature (e.g., with a heater or cooler) and/or humidity, such that the ambient air has substantially the same environmental characteristics of the room within which the dishwasher is located. In addition, in some embodiments, the ambient air is supplied to the mixing conduit independently from the supply of inlet air to the wash tub, such that the relative flow rates of the inlet air into the wash tub and the ambient air into the mixing conduit are independently controllable. In addition, in some instances, one or more of the fans may be variable speed fans, and the environmental conditions of the exhausted air and of the ambient environment (e.g., temperature and/or humidity) may be monitored during a drying phase of a wash cycle to control fan speed(s) to maintain the dew point of the exhausted air below the ambient room temperature.
With reference to
Exhaust fan 118 directs the humid air stream 122 into a first inlet 124 of a mixing conduit 126 that is in fluid communication with and downstream of the exhaust fan. In addition, a second inlet 128 of mixing conduit 126 is in fluid communication with an upstream mixing fan 130 that is configured to draw an ambient air stream 132 into second inlet 128 of mixing conduit 126. Within the mixing conduit, the humid and ambient air streams 122, 132 are mixed with one another, and exhausted from an outlet 134 of mixing conduit 136 as a mixed exhaust air stream 136.
In the illustrated embodiment, each of fans 106, 118, and 130 are variable speed fans, although in other embodiments, one or more of fans 106, 118, and 130 may be single speed. Each fan is controlled by a controller 138, which in some embodiments may be dedicated to the drying system, while in other embodiments, may be the main controller of dishwasher 100. Controller 138 may also control heater 112, and in some embodiments, may be capable of controlling the output power and/or heated inlet air stream 114 temperature. In other embodiments, however, heater 112 may simply be an on/off heater, and may not be regulated to a particular power level or air stream temperature.
Controller 138 may also be configured to receive various sensor inputs in order to control drying system 102. For example, one or more environmental sensors, e.g., temperature and/or humidity sensors, may be used to sense environmental conditions of one or more air streams. In the illustrated embodiment, for example, a temperature sensor 140 and humidity sensor 142 may be disposed within or proximate mixing conduit 126 (e.g., in outlet 134 or otherwise downstream of mixing conduit 126) in order to sense temperature and humidity of mixed exhaust air stream 136. In some embodiments, sensors 140 and 142 may also be combined into a single sensor. In addition, in some embodiments, an additional temperature sensor 144 and/or humidity sensor 146 may be used to sense ambient air conditions, e.g., in order to determine a temperature and/or dew point of the ambient air surrounding the dishwasher. In some embodiments, sensors 144, 146 may be disposed proximate an outlet of inlet fan 106, while in other embodiments, sensors 144, 146 may be disposed in other locations, e.g., proximate mixing fan 130 and upstream of mixing conduit 126. In still other embodiments, sensors 144, 146 may be omitted, and sensors 140 and/or 142 may be used to sense ambient air conditions, e.g., by capturing temperature and/or humidity prior to a wash cycle, or at least prior to the drying phase of a wash cycle.
With reference to
In addition, it will be appreciated that an inlet air conduit 150 may be used to route the heated inlet air stream from heater 112 to inlet 116 of wash tub 104, and an exhaust air conduit 152 may be used to route the humid air stream from outlet 120 of wash tub 104 to exhaust fan 118. Conduits 150, 152 are generally configured to route the air streams along the sidewalls of the wash tub from and to the space underneath the wash tub to limit the external visibility of the components of the drying system and stay within the required form factor of the dishwasher. It will also be appreciated that various vents, grates, filters, etc. may also be utilized in drying system 102 to provide access to the ambient environment around the dishwasher in an aesthetically acceptable manner.
An example implementation of an operational sequence that may be employed by controller 138 of
It will also be appreciated that a drying phase may be performed independently of or at different points within a wash cycle. It may be desirable, for example, to support a separate “dry only cycle,” or to periodically perform a drying phase or operation to prevent smells from building up in the wash tub.
Operational sequence 200 begins in block 202 by optionally capturing initial ambient temperature and humidity. As noted above, for example, it may be desirable in some embodiments to utilize only one temperature sensor 140 and one humidity sensor 142 disposed proximate the outlet of mixing conduit 126, and omit any additional sensors capable of sensing ambient environmental conditions. As such, at the start of a wash cycle, or in some instances, at other points in the wash cycle prior to the drying phase and prior to humid air being drawn from the wash tub, sensors 140, 142 may be used to capture ambient temperature and humidity. In other instances, ambient temperature and/or humidity may be captured incrementally throughout the day. Where additional sensors such as sensors 144, 146 are used, however, block 202 may be omitted. In addition, as noted above in connection with
Next, in block 204, the wash cycle is performed up to the drying phase, in a manner that will be understood by those of ordinary skill having the benefit of the instant disclosure. Thus, at the start of the drying phase, the wash tub is saturated with hot, humid air, and control passes to block 206 to start all fans on low speed. In some embodiments, the “low” fan speed may differ for each fan (and may be zero in some instances), and in some instances, the starting times at which each fan is started may differ (e.g., to delay starting the mixing fan). In some embodiments, for example, it may be desirable to maintain the wash tub environment at a lower pressure compared to the ambient environment, and to operate exhaust fan 118 at a speed that provides a higher flow rate of humid air out of wash tub 104 than the flow rate of inlet air into wash tub 104.
Next, in block 208, a heater temperature target (e.g., about 200 degrees Fahrenheit) may be set, and a loop may be initiated in block 210 to perform the drying phase until a drying phase completion criterion is met. In some embodiments, the criterion may be time based, while in other embodiments, the criterion may be based on sensed conditions, e.g., a humidity level sensed by humidity sensor 142 that is below a threshold, or within some threshold difference from the sensed ambient humidity. A time-based criterion may also be used to account for any sensor failures that inhibit meeting a humidity-based criterion within a predetermined period of time.
Assuming that the criterion is not met, block 210 passes control to block 212 to determine if an exit dew point, calculated based upon temperature and humidity readings captured by sensors 140, 142, is below ambient temperature (calculated in block 202 in some embodiments, or captured from temperature 144 in some embodiments). The exit dew point may be calculated from the temperature and humidity of the mixed exhaust air stream 136 in various manners understood by those of ordinary skill having the benefit of the instant disclosure, including, for example, the Magnus formula. In some embodiments, additional variables, e.g., atmospheric pressure, may also be sensed and utilized to calculate the dew point.
If the exit dew point is below ambient temperature, then there is a lowered risk that condensation will occur, so control passes to block 214 to determine if the inlet fan is currently at its maximum speed. If so, control passes to block 216 to decrement or decrease the mixing fan speed, and then control returns to block 210. If the inlet fan is not at its maximum speed, block 214 passes control to block 218 to increment or increase the exhaust and inlet fan speeds, such that the flow rate of the humid air stream supplied by exhaust fan 118 is increased relative to that of the ambient air stream supplied by mixing fan 130, and thus the volume of humid air in the mixed exhaust air stream is increased relative to that of the ambient air stream.
After block 218, block 220 determines if the inlet fan is above half speed (e.g., a PWM of 50% for a pulse modulated width-based fan control), and if so, passes control to block 222 to use the inlet vent as a target temperature for the heater. Control then returns to block 210. If, on the other hand, the inlet fan is not above half speed, block 220 skips block 222 and returns control to block 210, such that temperature directly next to the heater is used as the target temperature for the heater. In particular, in some embodiments, it may be desirable to sense temperature both directly next to the heater and farther downstream and proximate the inlet vent, but control the heater output at lower inlet fan speeds based upon the sensed temperature proximate the heater, while controlling the heater output at higher inlet fan speeds based upon sensed temperature further downstream. Doing so may mitigate large temperature gradients in the inlet conduit. In other embodiments, however, other manners of controlling the heater may be used, including control based on a temperature sensed at a single location. In still other embodiments, the heater output may be controlled independent from operational sequence 200.
Returning to block 212, if the exit dew point is not less than ambient temperature, then there is an increased risk that condensation will occur, so control passes to block 224 to determine if the mixing fan is at its maximum speed. If not, control passes to block 226 to increment or increase the mixing fan speed, such that the flow rate of the ambient air stream supplied by mixing fan 130 is increased relative to that of the humid air stream supplied by exhaust fan 118, and thus the volume of humid air in the mixed exhaust air stream is decreased relative to that of the ambient air stream. Control then returns to block 210.
Returning to block 224, if the mixing fan is at its maximum speed, control passes to block 228 to decrement the exhaust and inlet fan speeds, which further decreases the volume of humid air in the mixed exhaust air stream relative to that of the ambient air stream. Control then returns to block 210.
The loop initiated in block 210 therefore continues until the drying phase completion criterion is determined to be met, and with the relative speeds of the inlet, exhaust and mixing fans regulated to exhaust humid air from the wash tub as quickly as possible, while still maintaining the dew point of the exhausted air below ambient temperature. Once the completion criterion is met, operational sequence 200, and the drying phase, is complete.
It will be appreciated that the relative speeds of the fans, the amounts they are incremented or decremented, and their respective minimum and maximum speeds may vary in different embodiments. In some instances, these variables may be determined empirically for a particular dishwasher design. In addition, other variables associated with operational sequence, e.g., target temperatures, polling intervals, etc. may vary in different embodiments. Therefore, the invention is not limited to the specific implementation illustrated in
Drying systems other than that illustrated in
It will also be appreciated that, while certain features may be discussed herein in connection with certain embodiments and/or in connection with certain figures, unless expressly stated to the contrary, such features generally may be incorporated into any of the embodiments discussed and illustrated herein. Moreover, features that are disclosed as being combined in some embodiments may generally be implemented separately in other embodiments, and features that are disclosed as being implemented separately in some embodiments may be combined in other embodiments, so the fact that a particular feature is discussed in the context of one embodiment but not another should not be construed as an admission that those two embodiments are mutually exclusive of one another. Various additional modifications may be made to the illustrated embodiments consistent with the invention. Therefore, the invention lies in the claims hereinafter appended.
