Patent Publication Number: US-2015074917-A1

Title: Washing machine appliance and a method for detecting an oversuds condition

Description:
FIELD OF THE INVENTION 
     The present subject matter relates generally to washing machine appliances and methods for detecting oversuds conditions therein. 
     BACKGROUND OF THE INVENTION 
     Washing machine appliances generally include a tub for containing wash fluid, e.g., water, detergent, and/or bleach. A basket is rotatably mounted within the tub and defines a wash chamber for receipt of articles for washing. During operation of such washing machine appliances, wash fluid is directed into the tub and onto articles within the wash chamber of the basket. The basket can rotate at various speeds to agitate articles within the wash chamber in the wash fluid, to wring wash fluid from articles within the wash chamber, etc. 
     During operation of certain washing machine appliances, a spin cycle is performed to wring wash fluid from the articles within the wash chamber. The spin cycle typically entails rotating the basket at a relatively high rate of speed for a period of time. Typically, and desirably, the tub is generally empty of wash fluid and suds (caused by interaction between water and detergent, etc.). In some cases, however, an oversuds condition can occur, when suds remain in the tub during the spin cycle. If an oversuds condition occurs, the suds can overflow from the washing machine appliance and potentially damage, for example, surrounding floor areas. 
     Attempts have been made to reduce the risk of oversuds conditions in washing machine appliances. For example, additional water has been added before spin cycles in attempts to reduce suds within the tub and basket. The speed at which the basket rotates during the spin cycle has been reduced. The spin cycle ramp up period has been lengthened. Reductions in recirculation have been made. However, these attempts have not suitably reduced the risk of oversuds conditions occurring. 
     Accordingly, improved washing machine appliances and methods for detecting oversuds conditions in washing machine appliances are desired. In particular, methods and apparatus that result in improved reductions in the potential for oversuds conditions during spin cycles would be advantageous. 
     BRIEF DESCRIPTION OF THE INVENTION 
     In one embodiment, the present disclosure is directed to a method for detecting an oversuds condition in a washing machine appliance. The washing machine appliance has a tub and a basket rotatably mounted within the tub, the basket defining a chamber for receipt of articles for washing. The method includes measuring a pressure within the tub during a spin cycle, comparing the pressure to a threshold oversuds pressure level, and pausing the spin cycle and enacting an oversuds removal cycle if the pressure exceeds the threshold oversuds pressure level. 
     In another embodiment, the present disclosure is directed to a washing machine appliance. The washing machine appliance includes a tub and a basket rotatably mounted within the tub, the basket defining a chamber for receipt of articles for washing. The washing machine appliance further includes a valve, a spout configured for directing fluid from the valve into the tub, and a motor in mechanical communication with the basket, the motor configured for selectively rotating the basket within the tub. The washing machine appliance further includes a pressure sensor configured for measuring a pressure within the tub, and a controller in operative communication with the valve, the motor and the pressure sensor. The controller is configured for comparing the pressure measured during a spin cycle to a threshold oversuds pressure level, and pausing the spin cycle and enacting an oversuds removal cycle if the pressure exceeds the threshold oversuds pressure level. 
     These and other features, aspects and advantages of the present invention will become better understood with reference to the following description and appended claims. The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       A full and enabling disclosure of the present invention, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures. 
         FIG. 1  provides a perspective view of a washing machine appliance according to an exemplary embodiment of the present subject matter. 
         FIG. 2  provides a front, section view of the exemplary washing machine appliance of  FIG. 1 . 
         FIG. 3  is a flow chart illustrating a method according to an exemplary embodiment of the present disclosure. 
     
    
    
     DETAILED DESCRIPTION 
     Reference now will be made in detail to embodiments of the invention, one or more examples of which are illustrated in the drawings. Each example is provided by way of explanation of the invention, not limitation of the invention. In fact, it will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the scope or spirit of the invention. For instance, features illustrated or described as part of one embodiment can be used with another embodiment to yield a still further embodiment. Thus, it is intended that the present invention covers such modifications and variations as come within the scope of the appended claims and their equivalents. 
       FIG. 1  is a perspective view of a washing machine appliance  50  according to an exemplary embodiment of the present subject matter. As may be seen in  FIG. 1 , washing machine appliance  50  includes a cabinet  52  and a cover  54 . A backsplash  56  extends from cover  54 , and a control panel  58  including a plurality of input selectors  60  is coupled to backsplash  56 . Control panel  58  and input selectors  60  collectively form a user interface input for operator selection of machine cycles and features, and in one embodiment, a display  61  indicates selected features, a countdown timer, and/or other items of interest to machine users. A lid  62  is mounted to cover  54  and is rotatable between an open position (not shown) facilitating access to a wash tub  64  ( FIG. 2 ) located within cabinet  52  and a closed position (shown in  FIG. 1 ) forming an enclosure over tub  64 . 
       FIG. 2  provides a front, cross-section view of washing machine appliance  50 . As may be seen in  FIG. 2 , tub  64  includes a bottom wall  66  and a sidewall  68 . A wash basket or wash drum  70  is rotatably mounted within tub  64 . In exemplary embodiments as shown, basket  70  is rotatable about a vertical axis V. Thus, washing machine appliance  50  in these embodiments is generally referred to as a vertical axis washing machine appliance. Basket  70  defines a wash chamber  73  for receipt of articles for washing and extends, e.g., vertically, between a bottom portion  80  and a top portion  82 . Basket  70  includes a plurality of openings or perforations  71  therein to facilitate fluid communication between an interior of basket  70  and tub  64 . 
     A spout  72  is configured for directing a flow of fluid into tub  64 . In particular, spout  72  may be positioned at or adjacent top portion  82  of basket  70 . Spout  72  may be in fluid communication with a water supply (not shown) in order to direct fluid (e.g., liquid water) into tub  64  and/or onto articles within chamber  73  of basket  70 . A valve  74  regulates the flow of fluid through spout  72 . For example, valve  74  can selectively adjust to a closed position in order to terminate or obstruct the flow of fluid through spout  72 . A pump assembly  90  (shown schematically in  FIG. 2 ) is located beneath tub  64  and basket  70  for gravity assisted flow to drain tub  64 . 
     An agitation element  92 , shown as an impeller in  FIG. 2 , is disposed in basket  70  to impart an oscillatory motion to articles and liquid in chamber  73  of basket  70 . In various exemplary embodiments, agitation element  92  includes a single action element (i.e., oscillatory only), double action (oscillatory movement at one end, single direction rotation at the other end) or triple action (oscillatory movement plus single direction rotation at one end, singe direction rotation at the other end). As illustrated in  FIG. 2 , agitation element  92  is oriented to rotate about vertical axis V. Basket  70  and agitation element  92  are driven by a pancake motor  94 . As motor output shaft  98  is rotated, basket  70  and agitation element  92  are operated for rotatable movement within tub  64 , e.g., about vertical axis V. Washing machine appliance  50  may also include a brake assembly (not shown) selectively applied or released for respectively maintaining basket  70  in a stationary position within tub  64  or for allowing basket  70  to spin within tub  64 . 
     Operation of washing machine appliance  50  is controlled by a processing device or controller  100 , that is operatively coupled to the user interface input located on washing machine backsplash  56  (shown in  FIG. 1 ) for user manipulation to select washing machine cycles and features. In response to user manipulation of the user interface input, controller  100  operates the various components of washing machine appliance  50  to execute selected machine cycles and features. 
     Controller  100  may include a memory and microprocessor, such as a general or special purpose microprocessor operable to execute programming instructions or micro-control code associated with a cleaning cycle. The memory may represent random access memory such as DRAM, or read only memory such as ROM or FLASH. In one embodiment, the processor executes programming instructions stored in memory. The memory may be a separate component from the processor or may be included onboard within the processor. Alternatively, controller  100  may be constructed without using a microprocessor, e.g., using a combination of discrete analog and/or digital logic circuitry (such as switches, amplifiers, integrators, comparators, flip-flops, AND gates, and the like) to perform control functionality instead of relying upon software. Control panel  58  and other components of washing machine appliance  50  may be in communication with controller  100  via one or more signal lines or shared communication busses. 
     In an illustrative embodiment, laundry items are loaded into chamber  73  of basket  70 , and washing operation is initiated through operator manipulation of control input selectors  60 . Tub  64  is filled with water and mixed with detergent to form a wash fluid. Valve  74  can be opened to initiate a flow of water into tub  64  via spout  72 , and tub  64  can be filled to the appropriate level for the amount of articles being washed. Once tub  64  is properly filled with wash fluid, the contents of the basket  70  are agitated with agitation element  92  for cleaning of laundry items in basket  70 . More specifically, agitation element  92  is moved back and forth in an oscillatory motion. 
     After the agitation phase of the wash cycle is completed, tub  64  is drained. Laundry articles can then be rinsed by again adding fluid to tub  64 , depending on the particulars of the cleaning cycle selected by a user, agitation element  92  may again provide agitation within basket  70 . One or more spin cycles may also be used. In particular, a spin cycle may be applied after the wash cycle and/or after the rinse cycle in order to wring wash fluid from the articles being washed. During a spin cycle, basket  70  is rotated at relatively high speeds. 
     While described in the context of a specific embodiment of washing machine appliance  50 , using the teachings disclosed herein it will be understood that washing machine appliance  50  is provided by way of example only. Other washing machine appliances having different configurations (such as horizontal-axis washing machine appliances), different appearances, and/or different features may also be utilized with the present subject matter as well. 
     Referring still to  FIG. 2 , a pressure chamber  110  may be defined in the tub  64 . The pressure chamber  110  may be provided for facilitating tub pressure measurements. For example, a hose  112  may connect the pressure chamber  110  to a pressure sensor  114 . Pressure sensor  114  may measure the pressure in the pressure chamber  110  or at another suitable location within the tub  64 , and may be in operative communication with the controller  100 . The pressure sensor  114  may be a component of controller  100 , or may be a separate component from the controller  100  which is in communication with the controller  100  through a suitable wired or wireless connection. A pressure sensor  114  may, for example, be an analog pressure sensor, a digital pressure sensor, a mechanical pressure switch, or any other suitable device capable of measuring pressure as required herein. Pressure chamber  110  may include an inner opening  120  and an outer opening  122 , and may extend between these openings to place the interior of the tub  64  and the hose  112  in fluid communication. Inner opening  120  may thus be defined in a sidewall  68  of the tub  64 . 
     Further, a deflector  130  may be disposed within and mounted to the tub  64 , such as to a sidewall  68  and/or tub bottom  66  thereof. Deflector  130  generally extends inwardly from the sidewall  68  and tub bottom  66  between the tub  64  and basket  70 , and deflects and redirects water therein. Inner opening  120  may be defined adjacent to the deflector  130 , such that deflector  130  redirects water from the inner opening  120 . 
     As discussed, improved methods and apparatus for detecting, as well as reducing or eliminating, oversuds conditions are desired in the art. The present disclosure is thus further direction to methods for detecting oversuds conditions in washing machine appliances  50 . Such methods may advantageously reduce leakages and other issues caused by oversuds conditions by efficiently detecting and facilitating elimination of such conditions. Such methods are additionally unlikely to confuse oversuds conditions with normal washing machine appliance operations, thus increasing the efficiency and reliability of the washing machine appliances. Further, such methods are advantageously robust, and do not require parameter adjustments, when utilized with varying loads, fluid levels, detergent brands and amounts, fluid temperatures and hardnesses, etc. 
     For example, a method according to the present disclosure may include the step  200  of measuring a pressure  202  within the tub  64  during a spin cycle  204 . Such measurement may be taken in exemplary embodiments by pressure sensor  114  and in pressure chamber  110 . 
     During a typical spin cycle, the pressure  202  may generally read as approximately an atmospheric pressure level (gauge) due to the relative lack of fluids, such as wash fluids and suds. However, if an oversuds condition occurs, the pressure  202  may change. An oversuds condition is generally a condition wherein excess fluids, such as wash fluids and suds, are present in a tub. For example, in some embodiments, the existence of a deflector  130  adjacent to the pressure chamber  110  inner opening  120  may create a vacuum within the pressure chamber  110 , such as adjacent or in the inner opening  120 , during an oversuds condition. This may cause a negative pressure reading relative to the atmospheric pressure level. In other embodiments, the existence of an oversuds condition may cause a positive pressure reading relative to the atmospheric pressure level. 
     Accordingly, a method according to the present disclosure may further include the step  210  of comparing the pressure  202  to a threshold oversuds pressure level  212 . The threshold level  212  may be, for example, a relative positive or negative pressure level which is higher than or lower than the atmospheric pressure level. In some embodiments, for example, a threshold oversuds pressure level  212  may be between approximately 0.2 inches H 2 O and approximately 3.0 inches H 2 O above or below the atmospheric pressure level, such as between approximately 0.5 inches H 2 O and approximately 2.0 inches H 2 O above or below the atmospheric pressure level, such as in some exemplary embodiments approximately 0.5 inches H 2 O above or below the atmospheric pressure level. 
     Further, a method according to the present disclosure may include the step  220  of pausing the spin cycle  204  and enacting an oversuds removal cycle  222  if the pressure  202  exceeds the threshold oversuds pressure level  212 . Thus, a determination may be made by, for example controller  100  in communication with pressure sensor  114 , that the pressure  202  exceeds a threshold oversuds pressure level  212 . Such determining step may be denoted, for example, as step  225 . In embodiments wherein a threshold oversuds pressure level  212  is a relatively positive threshold pressure, the pressure  202  exceeds the threshold oversuds pressure level  212  when it is greater than the threshold oversuds pressure level  212 . In embodiments wherein a threshold oversuds pressure level  212  is a relatively negative threshold pressure, the pressure  202  exceeds the threshold oversuds pressure level  212  when it is less than the threshold oversuds pressure level  212 . 
     An oversuds removal cycle  222  may generally be a cycle which lessens the amount of suds within the tub  64 , thus reducing or eliminating the oversuds condition. For example, in some embodiments, an oversuds removal cycle  222  may include the step  230  of adding a fluid to the tub  64 . The fluid may, for example, in exemplary embodiments be a liquid such as water. Valve  74  and spout  72  may be utilized to supply such fluid. An oversuds removal cycle  222  may further include the step  232  of agitating the basket  70 . For example, motor  94  may be utilized to spin the basket  70 , as discussed above. An oversuds removal cycle  222  may further include the step  234  of draining the fluid from the tub  64 . For example, the fluid may be drained through conventional drain apparatus in the tub  64  and appliance  50 . Such steps, and the oversuds removal cycle  222  comprised thereof, may serve to dilute the existing suds in the tub  64  and reduce or eliminate the suds, thus reducing or eliminating an oversuds condition. 
     Details of one suitable oversuds removal cycle  222  may be established in accordance with methods described in U.S. Pat. No. 4,410,329 to Blevins et al. which issued on Oct. 18, 1983, the disclosure of which is incorporated by reference herein. 
     In some embodiments, a method according to the present disclosure may further include the step  240  of continuing the spin cycle  204  after the oversuds removal cycle  222  has concluded. Thus, normal operation of the appliance may continue after the oversuds condition has been reduced or eliminated. 
     In some embodiments, a method according to the present disclosure may further include the step  250  of continuing the spin cycle  204  in the pressure  202  does not exceed the threshold oversuds pressure level  212 . For example, pressures  202  may be compared to threshold oversuds pressure levels  212  during operation of the appliance  50 , and specifically during spin cycles, constantly or intermittently. Thus, a determination may be made by, for example controller  100  in communication with pressure sensor  114 , that the pressure  202  does not exceed a threshold oversuds pressure level  212 . Such determining step may be denoted, for example, as step  255 . If a pressure  202  does not exceed a threshold oversuds pressure level  212 , the spin cycle  204  may not pause, and rather may continue as per normal appliance  50  operation. 
     It should be understood that various method steps as discussed herein may be performed during appliance  50  operation by the controller  100  thereof. Thus, for example, a controller  100  may be configured for comparing the pressure  202  measured during a spin cycle  204  to a threshold oversuds pressure level  212 , and pausing the spin cycle  204  and enacting an oversuds removal cycle  222  if the pressure  202  exceeds the threshold oversuds pressure level  212 . The controller  100  may further be configured for continuing the spin cycle  202  after the oversuds removal cycle  222  has concluded, and continuing the spin cycle  204  if the pressure  202  does not exceed the threshold oversuds pressure level  212 . 
     This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they include structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.