Patent Publication Number: US-8984692-B2

Title: Active moisture removal in a laundry treating appliance

Description:
BACKGROUND OF THE INVENTION 
     Laundry treating appliances, such as clothes washers, clothes dryers, refreshers, and non-aqueous systems, have a treating chamber, which may have a configuration of a rotating drum, in which laundry items are placed for treating according to a cycle of operation. The laundry treating appliance may have a controller communicably and operably connected with the various components of the appliance for controlling the appliance to execute the cycle of operation. The cycle of operation may be selected manually by the user or automatically based on one or more conditions determined by the controller. 
     After the completion of the cycle of operation, the laundry may still contain moisture and/or there may still be moisture within the treating chamber or other areas of the appliance. If the moisture-laden laundry is left in the treating chamber too long, it may begin to mold or mildew, which may create a sour smell that most users find unpleasant. The moisture remaining within the treating chamber or other areas of the appliance may cause a similar result. 
     BRIEF DESCRIPTION OF THE INVENTION 
     The invention relates to an apparatus and method for actively dehumidifying the treating chamber of a laundry treating appliance to retard or eliminate the adverse effects of moisture-laden laundry remaining in the treating chamber or moisture remaining in the treating chamber or other areas of the appliance. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       In the drawings: 
         FIG. 1  is a schematic view of a laundry treating appliance according to a first embodiment of the invention. 
         FIG. 2  is a schematic view of a laundry treating appliance according to a second embodiment of the invention. 
         FIG. 3  is a schematic view of a control system of the laundry treating appliance of  FIG. 2  according to the second embodiment. 
         FIG. 4  is a flow chart illustrating a method for decreasing the humidity within a laundry treating appliance according to a third embodiment of the invention. 
         FIG. 5  is a flow chart illustrating a method for determining the humidity within a laundry treating appliance and controlling the operation of the laundry treating appliance in accordance with the determined humidity according to a fourth embodiment of the invention. 
     
    
    
     DESCRIPTION OF EMBODIMENTS OF THE INVENTION 
       FIG. 1  illustrates one embodiment of a laundry treating appliance according to the invention. The laundry treating appliance  10 , according to the invention, may be any appliance which performs a cycle of operation on laundry, non-limiting examples of which include a horizontal or vertical axis clothes washer; a combination washing machine and dryer; a tumbling or stationary refreshing/revitalizing machine; an extractor; a non-aqueous washing apparatus; and a revitalizing machine. 
     The laundry treating appliance  10  may comprise a cabinet  12  in having a controller  14  for controlling the operation of the laundry treating appliance  10  to complete a cycle of operation. A treating chamber  28  may be located within the cabinet  12  for receiving laundry to be treated during a cycle of operation. A treatment dispenser  32  may be fluidly coupled with the treating chamber  28  through a dispensing conduit  36  and operably coupled to the controller  14  to deliver a treatment chemistry to the treating chamber  28  during a cycle of operation in response to instructions from the controller  14 . 
     The laundry treating appliance  10  may further include a dehumidifying device  70 , which is illustrated as a fan, for dehumidifying the air within the laundry treating appliance  10 . The dehumidifying device  70  may dehumidify the air within the treating chamber  28  by venting and/or supplying air from the exterior of the treating chamber  28  to the interior of the treating chamber  28 . 
     While the dehumidifying device  70  is illustrated as a fan, the dehumidifying device  70  may be any device and/or material capable of dehumidifying the air within the laundry treating appliance  10 . Additional examples include a heat source, an evaporator, a condenser, or, a desiccant, for example. Any of these devices or materials may be used alone or in combination with another type of device or material. For example, the dehumidifying device  70  may include a fan for circulating air through the treating chamber  28  in addition to an incandescent light bulb for heating the contents of the treating chamber  28 . In another example, the dehumidifying device  70  may include a fan and a heating element, such as a resistive heating element or light bulb, for heating air circulated by the fan. As used herein, the term dehumidify may refer to both removing moisture from the air, replacing the air with less humid air, and drying a surface as a result of removal of moisture and moisture-laden air from the surface and surrounding environment. 
     The number and location of the dehumidifying device  70  may be selected to achieve the desired flow of air through the treating chamber  28  and level of dehumidification. As illustrated in  FIG. 1 , one example of a suitable location for the dehumidifying device  70  is the dispensing conduit  36 . The dehumidifying device  70  may be located within the dispensing conduit  36  for drawing air from the exterior of the treating chamber  28 , including exterior of the laundry treating appliance  10 , through the treatment dispenser  32  and into the treating chamber  28 . The treatment dispenser  32  may be open to the ambient air surrounding the laundry treating appliance  10  such that the dehumidifying device  70  may draw in or exhaust air from the treating chamber  28  through the treatment dispenser  32 . 
     In another example, the dehumidifying device  70  may be located within a vent tube, such as a child safety vent  74  that may exhaust to a rear side of the laundry treating appliance  10 . In yet another example, the dehumidifying device  70  may be coupled with the treating chamber  28  through a separate dehumidifying conduit  72 . The location of the dehumidifying device  70  may be selected to dry certain surfaces within the treating chamber  28  that are not normally cleaned during the wash process, such as the surfaces above the water fill line  73 . One or more dehumidifying devices  70  may be coupled with the treatment chamber  28  such that air flows to these locations to ensure drying of these surfaces. 
     As illustrated by the arrows  76  in  FIG. 1 , one or more of the dehumidifying devices  70  may be operated such that air is drawn in from the exterior of the laundry treating appliance  10  through the treatment dispenser  32  and into the treating chamber  28  to replace the air within the treating chamber  28 . The air from within the treating chamber  28  may then be exhausted to the rear of the laundry treating appliance  10  through the child safety vent  74  or the dehumidifying conduit  72 . The dispensing conduit  36 , the child safety vent  74  and/or dehumidifying conduit  72  may be provided with a dehumidifying device  70  either alone or in combination to facilitate the flow of air through the treating chamber  28 . 
     For example, the dehumidifying device  70  within the child safety vent  74  may be operated to draw air from the exterior of the laundry treating appliance  10  through the treatment dispenser  32  and dispending conduit  32  into the treating chamber  28 , where it may then be exhausted through the child safety vent  74 . A dehumidifying device  70  may also be provided within the dispensing conduit  32  to facilitate the movement of air from the exterior of the laundry treating appliance  10  through the treatment dispenser  36 . The process may also be operated in reverse such that air is drawn in through the child safety vent  74  and exhausted through the treatment dispenser  36 . 
     Alternatively, rather than drawing and exhausting air to the exterior of the laundry treating appliance  10 , air may be drawn in and/or exhausted into an interior space defined by the cabinet  12 . It is also within the scope of the invention for the air to be drawn into the treating chamber  28  through a conduit other than the dispensing conduit  36  or any other suitable opening which fluidly couples the treating chamber  28  with the interior space defined by the cabinet  12  or the exterior of the laundry treating appliance  10 . 
     In addition, the laundry treating appliance  10  may include one or more interior humidity sensors  80  for measuring the humidity within the treating chamber  28  and one or more exterior humidity sensors  82  for measuring the humidity of the environment in which the laundry treating appliance  10  is located. The interior and exterior humidity sensors  80  and  82  may be any suitable type of sensor or combination of sensors capable of determining relative or absolute humidity such as an infrared sensor, a capacitive sensor, a resistive sensor or a thermal conductivity sensor, for example. Alternatively, the interior and/or exterior humidity sensors  80 ,  82  may include a pressure and a temperature sensor for determining the dew point. The determined dew point may then be used to calculate the relative humidity. 
     The interior humidity sensor  80  may be located in any suitable location within the laundry treating appliance  10  for determining the humidity within the treating chamber  28 . For example, the interior humidity sensor  80  may be located anywhere along the air flow path  76 , such as in the treating chamber  28 , the dispensing conduit  36 , the child safety vent  74  and/or the dehumidifying conduit  72 . It is within the scope of the invention for multiple humidity sensors  80  to be located at multiple locations within the laundry treating appliance  10 . 
     The exterior humidity sensor  82  may be located anywhere in the cabinet  12  such that it may be able to determine the humidity of the environment in which the laundry treating appliance  10  is located. 
     As illustrated, the humidity sensors  80 ,  82  may be used to determine their respective internal/external humidity and output a signal indicative thereof. However, it is possible to use a single sensor that outputs a signal indicative of the difference between the internal/external humidity. 
     The controller  14  may be operably coupled with one or more components of the laundry treating appliance  10  for communicating with and controlling the operation of the component to complete a cycle of operation. For example, the controller  14  may be coupled with the treatment dispenser  32  for dispensing a treatment during a cycle of operation and the dehumidifying device  70  for dehumidifying the treating chamber  28 . 
     The controller  14  may also be coupled with the interior humidity sensor  80  for determining the humidity within the treating chamber  28  and the exterior humidity sensor  82  for determining the humidity of the exterior environment. The sensor reading or readings in the form of a signal may be sent to the controller  14  and analyzed using analysis software provided to the controller to determine the humidity within the treating chamber  28 . The signal may be analog, digital, continuous, or discontinuous. The signal may be indicative of an absolute value of the humidity or may be otherwise indicative of the humidity. For example, the output signal may be a voltage signal having an amplitude that is indicative of the absolute or relative humidity value. The type of the signal is not limiting. The controller  14  may then determine whether to activate or deactivate the dehumidifying device  70  based on the determined humidity within the treating chamber  28  and the humidity of the exterior environment. 
       FIG. 2  illustrates a second embodiment of the invention in the form of a washing machine  110  which is similar in structure to the laundry treating appliance  10 . Therefore, elements in the washing machine  110  similar to the laundry treating appliance  10  will be numbered with the prefix  100 . The washing machine  110  described herein shares many features of a traditional automatic washing machine, which will not be described in detail except as necessary for a complete understanding of the invention. 
     The washing machine  110  may comprise a cabinet  112  in which is provided a controller  114  that may receive input from a user through a user interface  115  for selecting a cycle of operation and controlling the operation of the washing machine  110  to implement the selected cycle of operation. A stationary tub  116  may located within the cabinet  112  and define an interior chamber  118 . 
     A rotatable drum  120  may be located within the interior chamber  118  and may include a plurality of perforations  121 . Liquid may flow between the tub  116  and the drum  120  through the perforations  121 . The drum  120  may further include one or more lifters or baffles  122  disposed on an inner surface of the drum  120  to lift fabric items contained in the drum  120  while the drum  120  rotates. The drum  120  may define a treating chamber  128  for receiving fabric items to be cleaned. 
     The drum  120  may be rotated by a suitable drive mechanism, which is illustrated as a motor  123  coupled to the drum  120  through a belt  124  and a drive shaft  125 . The motor  123  may be operably coupled to the controller  114  to control the rotation of the drum  120  to complete a cycle of operation. Other drive mechanisms, such as direct drive, may also be used. 
     Both the tub  116  and the drum  120  may be selectively closed by a door  126 . A bellows  127  may couple an open face of the tub  116  with the cabinet  112 , and the door  126  seals against the bellows  127  when the door  126  closes the tub  116 . 
     While the drum  120  is illustrated and described herein as defining the treating chamber  128 , the tub  116  and/or the drum  120  may be considered a receptacle, with either of them defining the treating chamber  128  for receiving fabric items to be treated. While the illustrated washing machine  110  includes both the tub  116  and the drum  120 , it is within the scope of the invention for the laundry treating appliance to include only one receptacle, with the receptacle defining the treating chamber  128  for receiving the fabric items to be treated. 
     The washing machine  110  of  FIG. 2  may further include a liquid supply and recirculation system. Liquid, such as water or water with a wash aid, may be supplied to the washing machine  110  from a water supply  129 , such as a household water supply. A first supply conduit  130  may fluidly couple the water supply  129  to a treatment dispenser  132 . An inlet valve  134  may control flow of the liquid from the water supply  129  and through the first supply conduit  130  to the treatment dispenser  132 . A dispensing conduit  136  may fluidly couple the treatment dispenser  132  with the tub  116 . 
     Liquid that flows from the treatment dispenser  132  through the flow conduit  136  to the tub  116  typically enters a space between the tub  116  and the drum  120  and may flow by gravity to a sump  138  formed in part by a lower portion  140  of the tub  116 . The sump  138  may also be formed by a sump conduit  142  that may fluidly couple the lower portion  140  of the tub  116  to a pump  144 . 
     The pump  144  may direct fluid to a drain conduit  146 , which may drain the liquid from the washing machine  110 , or to a recirculation conduit  148 , which may terminate at a recirculation inlet  150 . The recirculation inlet  150  may direct the liquid from the recirculation conduit  148  into the drum  120 . The recirculation inlet  150  may introduce the liquid into the drum  120  in any suitable manner, such as by spraying, dripping, or providing a steady flow of the liquid. 
     Still referring to  FIG. 2 , the washing machine  110  may include a sump heater  152  which may be located in the sump  138 . The sump heater  152  may be any type of heater and is illustrated as a resistive heating element for exemplary purposes. The sump  138  may also include a one-way check valve  153  for draining any liquid in the sump  138 . The sump heater  152  may be used alone or in combination with a steam generator  160  to add heat to the chamber  20 . 
     The washing machine  110  may optionally include a steam generation system including a steam generator  160  that may receive liquid from the water supply  129  through a second supply conduit  162 , optionally via a reservoir  164 . The inlet valve  134  may control flow of the liquid from the water supply  129  and through the second supply conduit  162  and the reservoir  164  to the steam generator  160 . A steam conduit  166  may fluidly couple the steam generator  160  to a steam inlet  168 , which may introduce steam into the tub  116 . The steam that enters the tub  116  through the steam inlet  168  may subsequently enter the drum  120  through the perforations  121 . Alternatively, the steam inlet  168  may be configured to introduce the steam directly into the drum  120 . 
     The type of steam generation system is not germane to the invention and may include any type of steam generator  160  that converts liquid to steam. For example, the sump heater  152  may also be operated as a steam generator in place of or in addition to the steam generator  160 . 
     The liquid supply and recirculation system and the steam generation system may differ from the configuration shown in  FIG. 2 , such as by inclusion of other valves, conduits, wash aid dispensers, and the like, to control the flow of liquid and steam through the washing machine  110  and for the introduction of more than one type of detergent/wash aid. 
     The washing machine  110  may further include a dehumidifying device  170 , which is illustrated as a dehumidifying fan, for dehumidifying the air within the washing machine  110 . The dehumidifying device  170  may dehumidify the air within the washing machine  110  by venting and/or supplying air from the exterior of the washing machine  110  to the tub  116 . While the dehumidifying device is illustrated as a dehumidifying device  170 , the dehumidifying device may be any device and/or material capable of dehumidifying the air within the washing machine  110 . It is within the scope of the invention for other types of dehumidifying devices to be used such as those discussed above with respect to the laundry treating appliance  10  illustrated in  FIG. 1 . 
     The dehumidifying device  170  may be fluidly coupled with the tub  116  through a first ventilation conduit  172  for venting the interior of the tub  116  which includes the interior chamber  118  and the treating chamber  128 . The treating chamber  128  may be fluidly coupled with the interior chamber  118  through the perforations  121  in the drum  120  such that air may flow between the two chambers. 
     In operation, the dehumidifying device  170  may draw in ambient air from the exterior of the washing machine  110  through the dispenser  132 , as illustrated by arrows  176 . The dispenser  132  may be provided such that the dispensing conduit  136  is fluidly connected with the ambient air exterior to the washing machine  110 . The air flow  176  may be drawn into the tub  116  from the dispenser  132  through the dispensing conduit  136  that may be coupled with the tub  116  or the bellows  127 . The air  176  drawn into the tub  116  may enter the interior chamber  118  and pass into the treating chamber  128  through the perforations  121  in the drum  120 . The air may exit the treating chamber  128  in the same manner. The air may be withdrawn from the tub  116  through the ventilation conduit  172  and exhausted to the outside of the washing machine  110  through the dehumidifying device  170 . In this manner, the dispenser  132 , dispensing conduit  136 , tub  116 , drum  120 , ventilation conduit  172  and dehumidifying device  170  provide a ventilation flow path for drawing ambient air into the tub  116  and exhausting air from the tub  116  to the exterior of the washing machine  110 . 
     The dehumidifying device  170  may be operated such that air is drawn into the tub  116  through the treatment dispenser  132  and exhausted through the ventilation conduit  172  as illustrated by the arrows  176 . Alternatively, the dehumidifying device  170  may be operated such that air is blown into the tub  116  through the ventilation conduit  172  and then exhausted through the treatment dispenser  132 . It is also within the scope of the invention for a user to select the desired direction of the air flow through the washing machine  110  through the user interface  115 . 
     The number and location of the dehumidifying device  170  may be selected to achieve the desired air flow path and level of dehumidification. For example, the location of the dehumidifying device  170  may be selected to dry certain surfaces of the tub  116  that are not normally cleaned during the wash process, such as the surfaces above the water fill line  173 . One or more dehumidifying devices  170  may be coupled with the tub  116  such that air flows to these locations to ensure drying of these surfaces. Multiple dehumidifying devices  170  may also be provided to facilitate the movement of air through the washing machine  110 . For example, an additional dehumidifying device  170  may be located within the dispensing conduit  136  to facilitate drawing air through the treatment dispenser  132 . 
     Alternatively, rather than drawing and exhausting air to the exterior of the washing machine  110 , air may be drawn in and/or exhausted into an interior space defined by the cabinet  112 . It is also within the scope of the invention for the air to be drawn into the treating chamber  128  through a conduit other than the dispensing conduit  136  or any other suitable opening which fluidly couples the treating chamber  128  with the interior space defined by the cabinet  112  or the exterior of the washing machine  110 . 
     In addition, the washing machine  110  may include one or more interior humidity sensors  180  for measuring the humidity within the tub  116  and one or more exterior humidity sensors  182  for measuring the humidity of the environment in which the washing machine  110  is located. The interior and exterior humidity sensors  180  and  182  may be any suitable type of sensor or combination of sensors capable of determining relative or absolute humidity such as an infrared sensor, a capacitive sensor, a resistive sensor or a thermal conductivity sensor, for example. Alternatively, the interior and/or exterior humidity sensors  180  and  182  may include a pressure and a temperature sensor for determining the dew point. The determined dew point may then be used to calculate the relative humidity. 
     The interior humidity sensor  180  may be located in any suitable location within the washing machine  110  for determining the humidity within the tub  116 . For example, the interior humidity sensor  180  may be located anywhere along the air flow path  176 , such as in the tub  116 , the ventilation conduit  172  or the dispensing conduit  136 . It is also within the scope of the invention for multiple interior humidity sensors  80  to be located at multiple locations along the air flow path  176 . 
     The exterior humidity sensor  182  may be located anywhere in the cabinet  112  such that it may be able to determine the humidity of the environment in which the washing machine  110  is located. 
     As illustrated in  FIG. 3 , the controller  114  may be provided with a memory  190  and a central processing unit (CPU)  192 . The memory  190  may be used for storing the control software that is executed by the CPU  192  in completing a cycle of operation using the washing machine  110  and any additional software, such as software for determining the size and type of the laundry, for example. The memory  190  may also be used to store information, such as a database or table, and to store data received from one or more components of the washing machine  110  that may be communicably coupled with the controller  114 . It is also within the scope of the invention for the controller  114  to be used with the laundry treating appliance  10  according to the first embodiment of the invention. 
     The controller  114  may be operably coupled with one or more components of the washing machine  110  for communicating with and controlling the operation of the component to complete a cycle of operation. For example, the controller  114  may be coupled with the motor  123  for controlling the direction and speed of rotation of the drum  120 ; the treatment dispenser  132  or steam generator  160  for dispensing a treatment during a cycle of operation; the sump heater  152  for heating the wash liquid during a cycle of operation; the pump  144  for recycling liquid from the sump  38  back to the drum  120 ; and the dehumidifying device  170  for venting the tub  116 . The controller  114  may also be coupled with the user interface  115  for receiving user selected inputs and communicating information to the user. 
     The controller  114  may also receive input from one or more sensors  194 , which are known in the art and not shown for simplicity. Non-limiting examples of sensors  194  that may be communicably coupled with the controller  114  include: a treating chamber  128  temperature sensor, a moisture sensor, a load size sensor, and a motor torque sensor. 
     For example, the controller  114  may be communicably coupled with a door sensor  196  for determining when the door  126  is opened and closed. The door sensor  196  may be any suitable type of sensor such as a mechanical pressure sensor or a magnetic sensor, for example. Alternatively, the door sensor  196  may be an optical sensor having a light emitting and light detecting means for determining if the door  126  is open or closed. In another example, the door sensor  196  may be in the form of an imaging device, such as a camera, that is capable of determining if the door  126  is open or closed. 
     The controller  114  may also be coupled with the interior humidity sensor  180  for determining the humidity within the tub  116  and the exterior humidity sensor  182  for determining the humidity of the environment surrounding the washing machine  110 . The sensor reading or readings may be sent to the controller  114  and analyzed using analysis software stored in the memory  190  to determine the humidity within the tub  116 . The controller  114  may then determine whether to activate or deactivate the dehumidifying device  170  based on the determined humidity within the tub  116 . 
     It is also within the scope of the invention for the interior and/or exterior humidity sensors  180 ,  182  to have a memory and a microprocessor for storing information and software and executing the software, respectively. In this manner, the interior and exterior humidity sensors  180  and  182  may analyze the data and communicate the results of the analysis with the controller  114 . 
     The previously described laundry treating appliances  10  and  110  may be used to implement one or more embodiments of a method of the invention. Several embodiments of the method will now be described in terms of the operation of the washing machine  110 . While the methods are described with respect to the washing machine  110 , the methods may also be used with the laundry treating appliance  10  of the first embodiment of the invention. The embodiments of the method function to automatically determine the humidity within the tub  116  and control the operation of the dehumidifying device  170  based on the determination. 
     High humidity levels, such as above 50-70% relative humidity or higher, for example, may contribute to an increase in the growth of microorganisms in the laundry and within the washing machine  110 . Under normal conditions and expected standards of operation, the high humidity levels are not reached. However, on some occasions, the user may forget to remove the laundry, causing the humidity in the treating chamber  128  to reach the high humidity levels. The growth of these microorganisms may generate an unpleasant odor that may permeate the laundry and pervade the washing machine  110 . Operation of the dehumidifying device  170  to draw ambient air into the tub  116  and exhaust the air within the tub  116  to the exterior of the washing machine  110  may decrease the humidity of the environment within the tub  116 , inhibiting the growth of these odor-producing microorganisms. The dehumidifying device  170  may also have an additional benefit of reducing the temperature of the laundry, which also facilitates the inhibition of the growth of microorganisms. 
     Referring now to  FIG. 4 , a flow chart of one embodiment  200  of the method for reducing the humidity within the tub  116  is disclosed. The sequence of steps depicted is for illustrative purposes only, and is not meant to limit the method  200  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 invention. 
     The method  200  starts at  202  during the execution of a cycle of operation. The cycle of operation may be any cycle of operation, including any one of the several well known cycles of operation, such as a wash cycle or refreshed cycle, to name a couple non-limiting examples. The dehumidifying process at  204  may be executed automatically by the controller  214  during or after the completion of the cycle of operation at  202  and may be initiated on a predetermined schedule following an event such as the selection of a cycle of operation or the closing of the door  126 . At  206  the dehumidifying process may be terminated. This may occur when the internal humidity reaches a predetermined threshold or reference value, which may be related to the external humidity. 
     Referring to  FIG. 5 , a flow chart of one embodiment of a method  300  for dehumidifying the washing machine  110  is disclosed. The method  300  may be executed by the controller  114  during at  204  of the method  200  shown in  FIG. 4 . The sequence of steps depicted is for illustrative purposes only, and is not meant to limit the method  300  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 invention. The humidity is reduced by determining the humidity in the treating chamber and controlling the operation of the dehumidifying device  170  based on the determined humidity to reduce the humidity. 
     The method  300  starts at  302  by obtaining at least one sensor reading from the interior humidity sensor  180 . The interior humidity sensor  180  may acquire a single reading or multiple readings. If the interior humidity sensor  180  acquires multiple readings, the readings may be processed, e.g. filtered or analyzed, before being communicated with the controller  114 . The readings acquired at  302  may be sent to the controller  114  for analysis at  304  using software that is stored in the memory  190  of the controller  114 . 
     At  306 , the controller  114  may use the sensor data analyzed at  304  to determine if the humidity within the tub  116  is above a predetermined threshold value. If the humidity is equal to or above the predetermined threshold value, the dehumidifying device  170  may be activated at  308 . 
     If the humidity is below the predetermined threshold value at  306 , the controller  114  may determine if the dehumidifying device  170  is already running at  310 . If the dehumidifying device  170  is already running, it may be deactivated at  312 . If the dehumidifying device  170  is not running, the controller  114  may maintain the dehumidifying device  170  in its deactivated state at  314 . 
     The method  300  at  302  through  314  may be repeated continuously or on a scheduled basis throughout the lifetime of the washing machine  110  or after an initiation event, such as the closing of the door  126  or the selection or completion of a cycle of operation. In this manner, the controller  114  may operate the dehumidifying device  170  only when the humidity value is above a predetermined threshold, such as 60% for example, to minimize the growth of odor-causing microorganisms within the tub  116 . Operating the dehumidifying device  170  only when it is may also have the additional benefit of increasing the lifespan of the dehumidifying device  170 . 
     Still referring to  FIG. 5 , the method  300  may also include an optional process  316  for comparing the measured humidity within the washing machine  110  determined in at  302  and  304  with the ambient humidity of the environment outside the washing machine  110 . According to this embodiment of the invention, the washing machine  110  may include an additional exterior humidity sensor  182 , which may be similar to interior humidity sensor  180 , for measuring the ambient humidity. If the humidity in the washing machine  110  determined at  304  is greater than the ambient humidity, then the dehumidifying device  170  may be activated at  308 . If the humidity in the washing machine  110  is less than or equal to the ambient humidity, the method may move to  110 . Alternatively, the dehumidifying device  170  may be activated if the difference between the humidity within the washing machine  110  determined by the interior humidity sensor  80  and the humidity determined by the exterior humidity sensor  82  is equal to or larger than a predetermined threshold. 
     Optional process  316  may be beneficial in environments where warm and humid weather occurs. The operation of the dehumidifying device  170  alone will not be able to decrease the humidity within the tub  116  to a level less than the humidity of the environment surrounding the washing machine  110 . Therefore, in an effort to reduce energy consumption and the expenditure of the lifespan of the dehumidifying device  170 ,  316  may be provided in the method  300  to only operate the dehumidifying device  170  when the conditions exist such that dehumidifying device  170  may reduce the humidity within the tub  116 . This optional process addresses the occasions where the ambient humidity is greater than the threshold humidity making it impossible or impractical to reduce the humidity below the threshold value. 
     Several methods may be used to analyze the sensor readings at  304 . If the interior humidity sensor  180  is an infrared humidity sensor, the interior humidity sensor  180  may determine the relative humidity and communicate the results directly with the controller  114 . If the interior humidity sensor  180  consists of a pressure sensor and a temperature sensor, the pressure and temperature data obtained at  302  may be analyzed at  304  to determine the dew point temperature. The dew point temperature may be determined at  304  by consulting a look-up table stored in the controller memory  190  containing the dew point temperature for a given pair of pressure and temperature values. Alternatively, the dew point temperature may be determined by the controller  114  using a known function relating dew point temperature to pressure and temperature. 
     The controller  114  may then use the determined dew point temperature to determine the relative humidity within the tub  116 . The relative humidity may be determined using an appropriate function relating the dew point temperature and measured temperature to the relative humidity or the controller  114  may consult a look-up table stored in the controller memory  190  containing values for relative humidity based on the dew point and measured temperature. 
     The exterior humidity sensor  182  may be used in the same manner as the interior humidity sensor  180  to determine the humidity of the environment exterior to the washing machine  110 . 
     The dehumidification of the tub  116  by the dehumidifying device  170  may be facilitated by removing as much liquid as possible from the tub  116  and other components of the washing machine  110 . One method to facilitate removal of liquid from the tub  116  may involve activating the pump  144  to pump away any liquid that remains or may accumulate over time in the lower portion  140  of the tub  116  after the completion of a cycle of operation. In systems that do not have a pump, such as a clothes dryer, for example, another method for decreasing the amount of water in the system may involve activating the one-way check valve  153  to drain any liquid that remains or may accumulate over time in the lower portion  140  of the tub  116  after the completion of a cycle of operation. The pump  144  or check valve  153  may be connected with the controller  114  such that it is activated at the same time as the dehumidifying device  170  or at the start of the method  100  illustrated in  FIG. 5 . In another example, the pump  144  may be activated to remove any water that accumulates in the lower portion  140  of the tub  116 . 
     In another example, the washing machine  110  may be provided with a heat source, such as a resistive heating element or an incandescent light bulb, for example, that may promote the evaporation of any liquid remaining in the tub  116  or other components of the washing machine  110 . The heat source may be connected with the controller  114  such that it is activated at the same time as the dehumidifying device  170 . For example, the heat source may be activated at the same time as the dehumidifying device  170  to heat the air as it is drawn into the treating chamber  128 . 
     In another example, the washing machine  110  may be provided with a condensing apparatus, such as a thermal electric cooler, for example, to promote condensation of moisture from the air. The condensing apparatus may promote removal of moisture from the air by cooling the air such that the moisture condenses. In another example, the condensing apparatus may promote the removal of moisture from the air by changing the pressure. The condensing apparatus may be fluidly coupled with the sump  142  such that the condensed moisture may be drained from the washing machine  110  by the pump  144 . 
     Inhibiting the growth of microorganisms through the activation of the dehumidifying device  170  may also be facilitated by modifying existing cycles of operation or initiating additional cycles. For example, the growth of microorganisms is not only related to the humidity within the tub  116  but also to the water content of the laundry load. Existing cycles of operation may be modified such that the water content in the laundry at the end of the cycle is below a predetermined threshold value that may be determined empirically for different types of fabrics, fabric blends and fabric sizes and stored in the controller memory  190 . Alternatively, the predetermined threshold value may be determined automatically based on the type of fabrics, fabric blends and fabric sizes according to an algorithm stored in the controller memory  190 . The decrease in laundry water content and the decrease in tub humidity may both contribute to inhibiting the growth of microorganisms. 
     For example, it has been found that decreasing the water content in a load consisting of cotton fabrics to less than 15% in combination with active venting of the tub  116  by the dehumidifying device  170  is very effective at inhibiting the growth of microorganisms within the laundry when the laundry is left in the washing machine  110  for an extended period of time after the completion of a cycle of operation. The desired water content level that may be used in combination with active venting by the dehumidifying device  170  may vary depending on the type of fabric in the load. For example, to achieve the same level of inhibition of growth as the cotton load, the water content in a load of synthetic fabrics, such as polyester, may need to be as low as 4%. 
     The activation of the dehumidifying device  170  may also be combined with an additional tumble cycle after the completion of the user selected cycle of operation. Rotation of the drum  120  resulting in tumbling of the laundry load may facilitate evaporation of liquid from the laundry by exposing more of the surface of the laundry. In addition, tumbling of the laundry may contribute to the inhibition of growth by providing an unstable substrate (the laundry fabric) on which many microorganisms find it difficult to propagate. Evaporation of additional liquid from the laundry and subsequent removal of the humid air from the tub  116  by the dehumidifying device  170  may decrease the growth of odor-causing microorganisms in the laundry. Tumbling of the laundry load and activation of the dehumidifying device  170  may be used independently to inhibit the growth of microorganisms. Alternatively, the tumbling and the activation of the dehumidifying device  170  may be combined to provide an additive or synergistic effect to inhibit the growth of microorganisms. The rate and number of rotations of the drum  120  may be set such that the amount of mechanical damage to the load is less than the mechanical damage that occurs in the course of a cleaning cycle of operation. 
     The apparatus and methods described herein facilitate the inhibition of the growth of microorganisms that may generate unpleasant odors in the laundry load and laundry treating appliance. The use of humidity sensors to determine when to operate a dehumidifying process allows the process to be initiated based on the conditions within the system, not simply based on an event, such as the door remaining closed after the completion of the cycle of operation or an elapsed time. Condition variables such as the remaining moisture content of the load, the type of fabrics in the load, load size and the temperature of the final rinse cycle may all effect the growth rate of microorganisms. Operating the dehumidifying process based on an event such as elapsed time or the status of the door may not be able to account for the effect these variables have on the system. This may results in the dehumidifying process not being initiated in time to inhibit the growth of microorganisms and/or result in premature termination of the dehumidifying process before the humidity within the laundry treating appliance has been decreased to a level at which the growth of microorganisms is inhibited. The use of a humidity sensor allows the dehumidifying process to be initiated when it is needed, including during a cycle of operation, depending on the conditions within the system. The dehumidifying process may continue to operate until the conditions have changed such that the risk of the growth of microorganisms is significantly reduced or eliminated. 
     In addition, basing the dehumidifying process on whether or not the user opens the door after the completion of a cycle of operation only accounts for effects that the remaining moisture content in the load has on the growth of microorganisms, it does not account for the effects of moisture remaining in other parts of the washing machine. For example, moisture remaining in areas such as the dispensing system or surfaces of the tub that are not normally cleaned during a wash cycle may contribute to the growth of microorganisms in the laundry treating appliance that may lead to an unpleasant odor. The use of humidity sensors to determine if a dehumidifying process should be operated allows the process to be operated when it is needed based on the conditions in the laundry treating appliance that directly effect the growth of microorganisms, regardless of the status of the door or the presence of laundry within the system. In this manner, the growth of microorganisms both within the laundry and within the laundry treating appliance system may be inhibited. 
     An additional advantage of the use of humidity sensors to determine when to operate a dehumidifying process may be the increase in energy efficiency of the washing machine. An exterior humidity sensor may be used to determine the humidity of the environment exterior to the laundry treating appliance and the dehumidifying process may be operated accordingly such that energy is not wasted in an attempt to decrease the humidity within the laundry treating appliance to a level below the surrounding environment. This feature may be especially useful in environments where the weather may be hot and/or humid. Prior attempts to reduce the humidity in the treating chamber relied on time-based control of an exhaust fan. Such a time based approach tends to waste energy in humid environments as the fan continues to run without a further reduction in the internal humidity. The embodiments of the invention described herein address these shortcomings of the prior devices. In addition, operating the dehumidifying device only when needed may increase the lifetime of the device, providing increased cost savings and convenience to the user over the lifetime of the appliance. 
     While the different embodiments have been individually described, it is within the scope of the invention to combine the various elements of each embodiment with each other. Thus, the elements from all of the embodiments may be mixed or combined as desired. Elements in a single embodiment, not otherwise described as being combinable, may also be combined as desired. 
     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, and the scope of the appended claims should be construed as broadly as the prior art will permit. It should also be noted that all elements of all of the claims may be combined with each other in any possible combination, even if the combinations have not been expressly claimed.