Patent Publication Number: US-10329707-B2

Title: Laundry treating appliance with pre-filter backwashing

Description:
BACKGROUND OF THE INVENTION 
     Laundry treating appliances, such as clothes washers, typically include a tub in which is mounted a rotatable wash basket for treating laundry articles according to a treating cycle of operation. The laundry articles may include dyed fabric articles. Depending on a variety of factors, the dye may loosen from a dyed article and become mixed with the wash liquid, along with non-dye materials such as lint. It is known to use a dye filter to capture the dye from the wash liquid to minimize contamination of laundry articles by the dye in the liquid. However, non-dye materials inhibit the efficacy of dye filters. 
     BRIEF DESCRIPTION 
     A method for operating a laundry treating appliance having a treating chamber for receiving a load of laundry for treatment includes performing a cycle of operation on the load of laundry wherein a dye-containing liquid is generated in the treating chamber, pumping the dye-containing liquid from the treating chamber through an upstream end of a pre-filter to remove non-dye material from the dye-containing liquid and from a downstream end of the pre-filter to a dye filter to remove dye from the dye containing liquid, and backwashing the pre-filter to remove the non-dye material from the pre-filter. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         FIG. 1  is a schematic cross-sectional view of a laundry treating appliance having a dye filter system, according to a first embodiment of the invention, illustrating the dye filter system is under a dye filtering step. 
         FIG. 2  is a schematic view of a controller of the laundry treating appliance of  FIG. 1 . 
         FIG. 3  is a schematic cross-sectional view of the laundry treating appliance of  FIG. 1  having the dye filter system, according to the first embodiment of the invention, illustrating the dye filter system under a backwashing step. 
         FIG. 4  is a schematic cross-sectional view of the laundry treating appliance according to a second embodiment of the invention, illustrating the flow of liquid reversed by gravity. 
         FIG. 5  is a schematic cross-sectional view of the laundry treating appliance according to a third embodiment of the invention, illustrating the backwashing step using both a recirculation pump and a drain pump. 
         FIG. 6  is a schematic cross-sectional view of the laundry treating appliance according to a fourth embodiment of the invention, illustrating the backwashing step without any valves. 
     
    
    
     DETAILED DESCRIPTION 
     Referring now to the figures,  FIG. 1  is a schematic view of an exemplary laundry treating appliance  10  in the form of a washing machine having a dye filter system, according to a first embodiment of the invention. While the laundry treating appliance  10  is illustrated as a vertical axis, top-fill washing machine, the invention may have applicability in other laundry treating appliances, such as a horizontal axis washing machine, combination laundry treating appliance and dryer, an extractor, a non-aqueous laundry treating appliance, and a tumbling or stationary refreshing/revitalizing machine, for example. 
     The washing machine  10  may include a cabinet or housing  12  and an imperforate tub  14  that defines an interior  15  of the washing machine  10 . A sump  16  may be in fluid communication with the interior  15  of the tub  14 . A drum or perforated wash basket  18  may be located within and rotatable relative to the interior  15  of the tub  14  and may define a laundry treating chamber  19  in the form of a deep fill chamber for receiving a laundry load. The wash basket  18  may include a plurality of perforations or apertures (not shown) such that liquid supplied to the wash basket  18  may flow through the perforations to the tub  14 . An agitator or clothes mover  20  may be located within the laundry treating chamber  19  and rotatable relative to and/or with the wash basket  18 . 
     The wash basket  18  and/or the clothes mover  20  may be driven by an electrical motor  22 , which may or may not include a gear case, operably connected to the wash basket  18  and/or the clothes mover  20 . The clothes mover  20  may be commonly oscillated or rotated about its axis of rotation during a cycle of operation in order to provide movement to the fabric load contained within the laundry treating chamber  19 . The wash basket  18  may be rotated at high speed to centrifugally extract liquid from the fabric load and to discharge it from the wash basket  18 . The top of the housing  12  may include a selectively openable lid  24  to provide access into the laundry treating chamber  19  through the open top of the wash basket  18 . 
     Still referring to  FIG. 1 , a spraying system  30  may be provided to spray liquid, such as water or a combination of water and one or more treating agents into the open top of the wash basket  18  and onto laundry placed within the laundry treating chamber  19 . Non-limiting examples of treating chemistries that may be dispensed by the dispensing system during a cycle of operation include one or more of the following: water, surfactants, enzymes, fragrances, stiffness/sizing agents, wrinkle releasers/reducers, softeners, antistatic or electrostatic agents, stain repellants, water repellants, energy reduction/extraction aids, antibacterial agents, medicinal agents, vitamins, moisturizers, shrinkage inhibitors, and color fidelity agents, and combinations thereof. 
     The spraying system  30  may be configured to supply water directly from a household water supply  32  and/or from the tub  14  and spray it onto the laundry through a sprayer  33 . The spraying system  30  may also be configured to recirculate liquid from the tub  14 , including the sump  16 , and spray it onto the laundry. The spraying system  30  can also include additional sprayers and other components to supply liquid to one or more additional locations, such as a portion of the interior  15  between the wash basket  18  and the tub  14 , an exterior surface of the wash basket  18 , an interior surface of the wash basket  18  and an internal surface of the tub  14 . The nature of the spraying system is not germane to the invention, and thus any suitable spraying system may be used with the laundry treating appliance  10 . 
     A pump  34  may be housed below the tub  14 . The pump  34  may have an inlet  36  fluidly coupled to the sump  16  and an outlet  38  configured to fluidly couple to a recirculation conduit  42 . In this configuration, the pump  34  may be used to drain or recirculate liquid in the sump  16 , which is initially sprayed into the wash basket  18 , flows through the wash basket  18 , and then into the sump  16 . It is understood that the pump  34  may be configured to switch the pumping direction by operating the motor coupled to the pump  34  in the reverse direction. It is also understood that the location and number of the pump  34  are not limited. Instead, one or more pumps may be located anywhere in the laundry treating appliance  10  as long as the pump is provided with the liquid via any conduit. 
     Alternatively, two separate pumps, such as a recirculation pump and a drain pump, may be used instead of the single pump as previously described, in which case, at least one of the recirculation pump or the drain pump may be fluidly coupled to a drain conduit for flushing the liquid out of the laundry treating appliance  10  according to a treating cycle of operation. It is understood that the recirculation pump, similar to the pump  34 , may be configured to switch the pumping direction by operating the motor in the reverse direction. 
     A dye filter system  43  may be provided for removing dye from the dye-containing liquid. The dye filter system  43  may include a pre-filter  44 , a dye filter  46 , a plurality of valves  48 ,  50 ,  52 , and a drain conduit  54 . The dye filter system  43  also includes a plurality of conduits  42 ,  56 ,  58 , which are fluidly coupled to at least one of the pre-filter  44 , dye filter  46  and valves  48 ,  50 ,  52 , for selectively passing the liquid received from the sump  16 . It may be understood that the dye filter system  43  is illustrated as positioned exteriorly of the housing  12  of the washing machine  10 ; in another embodiment, the dye filter system  43  may be housed in the interior of the housing  12 . 
     The pre-filter  44  may be positioned between the pump  34  and the dye filter  46  for removing any non-dye material in the liquid before the liquid flows to the dye filter. The pre-filter  44  may comprise a mesh screen, with an opening size of the mesh screen typically ranging from 25 to 500 microns. The dye filter  46  may be configured to fluidly couple the pre-filter  44  to the sprayer  33  for removing dye from the liquid. In the illustrated embodiment the dye filter  46  may be positioned above the pre-filter  44 , but it will be understood that a vertical orientation is not required for the invention. Non-limiting examples of the dye filter  46  include activated carbon, Nylon Beads, Poly(vinylpyridine), clay, ground corn cob, and treated cellulose. It is also understood that the height H of conduit between the pre-filter  44  and the dye filter  46  in the illustrated embodiment may be adjusted as necessary. 
     The first, second and third valves  48 ,  50 ,  52  are provided to the dye filter system  43  to control the flow direction of liquid. The valves  48 ,  50 ,  52  may be in the form of diverter valves, such that the flow of liquid may be controllably diverted. Alternatively, the valves  48 ,  50 ,  52  may be any valves that may reverse the liquid flow through the valve. 
     The first valve  48  may be positioned between the pump  34  and the upstream end of pre-filter  44  for controlling the flow either to the pre-filter  44  or to the drain conduit  54 . The second valve  50  may be positioned between the pump  34  and the first valve  48  for controllably diverting the liquid either to the recirculation conduit  56  or a bypass conduit  58 . The third valve  52  may be positioned between the downstream end of the pre-filter  44  and the upstream end of the dye filter  46 . The third valve  52  may divert the liquid to the upstream end of the dye filter  46  either from the bypass conduit  58  or from the downstream end of the pre-filter  44 . 
     As used herein, the term liquid typically includes a combination of water and one or more treating chemistries or treating agent capable of treating laundry according to a cycle of operation. The term liquid may also include water supplied from the household water supply  32  that has not been mixed with a treating agent prior to being applied to the laundry. 
     One or more sensors may be provided to the washing machine  10  to control the flow of liquid through the washing machine  10 . Non-limiting examples of the sensors include flow rate sensor, chemical sensor, water level sensor, temperature sensor, and the like. 
     The washing machine  10  also includes a control system for controlling the operation of the washing machine  10  to implement one or more treating cycles of operation. The control system may include a controller  60  located within the cabinet  12  and a user interface  62  that is operably coupled with the controller  60 . The user interface  62  may include one or more knobs, dials, switches, displays, touch screens and the like for communicating with the user, such as to receive input and provide output. The user may enter different types of information including, without limitation, cycle selection and cycle parameters, such as cycle options. 
     The controller  60  may include the machine controller and any additional controllers provided for controlling any of the components of the washing machine  10 . For example, the controller  60  may include the machine controller and a motor controller. Many known types of controllers may be used for the controller  60 . The specific type of controller is not germane to the invention. It is contemplated that the controller  60  is a microprocessor-based controller that implements control software and sends/receives one or more electrical signals to/from each of the various working components to effect the control software. As an example, proportional control (P), proportional integral control (PI), and proportional derivative control (PD), or a combination thereof, a proportional integral derivative control (PID control), may be used to control the various components. 
     As illustrated in  FIG. 2 , the controller  60  may be provided with a memory  70  and a central processing unit (CPU)  72 . The memory  70  may be used for storing the control software that is executed by the CPU  72  in implementing a cycle of operation using the washing machine  10  and any additional software. Examples, without limitation, of cycles of operation include: wash, heavy duty wash, delicate wash, quick wash, pre-wash, refresh, rinse only, and timed wash. A common wash cycle includes a wash phase, a rinse phase, and a spin extraction phase. Other phases for cycles of operation include, but are not limited to, intermediate extraction phases, such as between the wash and rinse phases, and a pre-wash phase preceding the wash phase, and some cycles of operation include only a select one or more of these exemplary phases. 
     The memory  70  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  10  that may be communicably coupled with the controller  60 . The database or table may be used to store the various operating parameters for the one or more treating cycles of operation, including factory default values for the operating parameters and any adjustments to them by the control system or by user input. 
     The controller  60  may be operably coupled with one or more components of the washing machine  10  for communicating with and controlling the operation of the component to complete a cycle of operation. For example, the controller  60  may be operably coupled with the motor  22 , the pump  34 , and the spraying system  30  to control the operation of these and other components to implement one or more of the cycles of operation. 
     The controller  60  may also be coupled with one or more sensors  64  provided in one or more of the systems of the washing machine to receive input from the sensors  64 , which are known in the art and not shown for simplicity. Non-limiting examples of sensors  64  that may be communicably coupled with the controller  60  include: a flow rate sensor, a chemical sensor, a temperature sensor, a moisture sensor, a weight sensor, a position sensor and a motor torque sensor, which may be used to determine a variety of laundry treating appliance system and laundry characteristics. 
     The controller  60  may further be operably coupled with the valves  48 ,  50 ,  52  for controlling the flow direction of the liquid for operating the dye filter system  43 . In one example, the controller  60  may control the flow direction of the liquid based on the information communicably received from one or more sensors  64 . 
     The controller  60  is used to implement a treating cycle of operation, wherein the treating cycle of operation may include a wash phase in which a liquid, e.g., water or a mixture of water and one or more treating chemistries, is applied to the laundry, a rinse phase in which the liquid is removed from the laundry by rinsing the laundry with rinse liquid, and a spin extraction phase in which at least a portion of the rinse liquid is extracted from the laundry by spinning the laundry at high speeds. 
     The laundry article may comprise dyed fabric, and the dye in the fabric may not be permanently coupled to the fabric. Instead, depending on factors such as the parameters of a treating cycle of operation, the nature of the dye, or the nature of the fabric, dye may be loosened from the fabric, and released to be free in the liquid. The dye, once in the liquid, may move freely in the liquid, and may adhere to or be adsorbed by laundry articles comprising fabrics where such contamination is unwanted. As a result, when a treating cycle of operation is complete, the laundry may have undesirable effects caused by dyes. To prevent the contamination of laundry articles by dye in the liquid, the dye may be captured by the dye filter  46  while the liquid is recirculated through the laundry treating appliance. 
     While the liquid includes dye that may need to be removed to minimize cross contamination of laundry, it is also understood that the liquid may also include non-dye material. Non-dye material may refer to an impurity material that is physically and/or chemically coupled to the laundry articles, and may be larger in size than chemical dye. For example, a piece of paper towel or paper tissue may be received in the pocket of a pair of pants prior to being subject to a cycle of operation in the liquid. In another example, small pieces of food may also be stuck to the laundry for a treating cycle of operation. In yet another example, lint material may be released from the laundry articles, and then mixed with the liquid. 
     During the recirculation of liquid in a treating cycle of operation, the liquid may be supplied from the sump  16  to the sprayer  33  by way of the dye filter system  43 , as illustrated in  FIG. 1 . The liquid is first pumped from the sump  16 , passes through the pre-filter  44  and the dye filter  46 , respectively, and then supplied back to the laundry treating chamber  19  via the sprayer  33 . It may be understood that the flow path of liquid during the dye filtering step is set to be identical to the one during liquid recirculation. That said, when the liquid is recirculated during a cycle of operation, the dye in the liquid is also filtered in the dye filtering step. 
     For the dye filtering step, the second valve  50  may be set to a second position to pass the liquid from the pump  34  to the first valve  48 . The first valve  48  may be set to a second position such that the liquid may be supplied from the second valve  50  to the upstream end of the pre-filter  44 . 
     When the liquid passes through the pre-filter  44 , the non-dye material may be filtered by the pre-filter  44 . A portion of the non-dye material may be simply blocked from passing the pre-filter  44 , and may stay in the liquid. Over time non-dye material may begin to build-up at the upstream end of the pre-filter  44 . In one example, the amount of non-dye material build-up in the pre-filter  44  may be proportional to the operation time of the washing machine  10 . For example, the longer the washing machine  10  operates, the greater will be the amount of non-dye material captured by the pre-filter  44 . With further increase in the operation time of the washing machine  10 , the non-dye material may be further pushed by the pressure exerted by the liquid during the recirculation, and eventually captured toward the interior of the pre-filter  44 , away from the surface of the pre-filter  44 . The build-up of the non-dye material may at least partially block the openings of the pre-filter  44 , and correspondingly impede the flow of liquid through the pre-filter  44 . As a result, the liquid passing through the pre-filter  44  downstream may be at a reduced flow rate and/or reduced pressure, compared to the liquid at the upstream end of the pre-filter  44 . 
     The third valve  52  may be set to a second position to pass the liquid from the downstream end of the pre-filter  44  to the upstream end of the dye filter  46 . The dye in the liquid may be removed by the dye filter  46 , and the liquid, now free from dye, may be supplied to the sprayer  33  to provide a liquid spray to the laundry articles in the laundry treating chamber  19 . 
     Referring to  FIG. 3 , the laundry treating appliance with the dye filter system  43  in a backwashing step is illustrated, where the pre-filter  44  is backwashed by diverting liquid to the pre-filter  44  to remove non-dye material that has built up in the pre-filter  44 . 
     The backwashing step may be performed when it is determined that the pre-filter  44  is blocked from passing the liquid. The blockage of the pre-filter  44  may be determined by monitoring the operating conditions of the washing machine  10 . For example, during a treating cycle of operation, if the flow rate sensor determines that the flow rate of the liquid passing through the dye filter  46  is below a threshold, it may be determined that the pre-filter  44  is clogged by the build-up of non-dye material, and the controller  60  may perform the backwashing step. 
     Alternatively, the backwashing step may be determined based on the performance of the dye filter  46 . In one example, when there is a decrease in the adhesion force between dye and dye filter  46  below a threshold, as determined by the chemical sensor, the pre-filter  44  may include a blockage in the pre-filter  44 , and the controller  60  may begin a backwashing step to increase the liquid flow to the dye filter  46  and decrease the adhesion force between dye and the dye filter. 
     Alternatively, the backwashing step may be incorporated into a treating cycle of operation for the washing machine  10 , such as at least one of prior to, during, and after the cycle of operation, independent of information from sensor indicating that the pre-filter  44  is blocked. For example, the backwashing step may be performed every time after a cycle of operation is complete or prior to a cycle of operation. 
     The backwashing step may be conducted by diverting the liquid to the downstream end of the pre-filter  44 . For this, the second valve  50  may be set to a first position to direct the liquid from the sump  16  to the third  52 . The third valve  52  may be set to a first position for directing the liquid from the second valve  50  to the downstream end of the pre-filter  44 . When the pre-filter  44  is provided with the liquid from the downstream end, the liquid may transfer kinetic energy to the non-dye material collected to the pre-filter  44  toward the upstream end of the pre-filter  44 . As a result, the non-dye material may be removed from the pre-filter  44 . 
     During the backwashing step, the first valve  48  may be set to a first position to direct the liquid, which now includes non-dye material decoupled from the pre-filter  44 , to the drain conduit  54 . After the backwashing step, additional water may be optionally supplied from a household water supply  32  into the treating chamber  19  for making up the liquid drained during the backwashing step. 
     Referring to  FIG. 4 , a second embodiment for backwashing the pre-filter  44  is illustrated, where the flow direction of liquid is reversed by gravity for backwashing the pre-filter  44 . As illustrated, the backwashing of the pre-filter  44  by gravity may not need the second and third valves,  50 ,  52 , as well as the bypass conduit  58 , compared to the first embodiment illustrated in  FIG. 3 . 
     During the dye filtering step, the liquid in the sump may be continuously circulated through in the order of the pump  34 , the pre-filter  44 , and then the dye filter  46 , for continuously removing the dye in the liquid, as previously described for  FIG. 1 . When it is determined that backwashing step may be necessary, the pump  34  may be turned off by the controller  60 . Once the pump  34  is turned off, the liquid upwardly passing the conduit  56  between the pre-filter  44  and dye filter  46  may lose the driving force from the pump  34 , and may not further be upwardly pumped. 
     Instead, the liquid may reverse the flow direction and flow downwardly by gravity to the downstream end of the pre-filter  44 . Since the liquid under gravity is provided with kinetic energy that is proportional to the conduit height H between the pre-filter  44  and the dye filter  46 , the liquid may transfer the kinetic energy to the non-dye material in the pre-filter  44  in a similar way to the embodiment as illustrated in  FIG. 3 . The first valve  48  may be set to the first position to divert the liquid with the non-dye material from the upstream end of the pre-filter  44  to the drain conduit  54 . 
     While the liquid in the volume of conduit  56  between the pre-filter  44  and dye filter  46  may be enough for backwashing the pre-filter  44 , it may be noted that a liquid container (not shown) may also be added to the dye filter system  43  for temporarily storing the liquid for offering increased amount of liquid to backwash the pre-filter  44 . In one example, the liquid container may be positioned to fluidly couple the pre-filter  44  and the dye filter  46 , while the liquid container may be positioned between the downstream end of dye filter  46  and the sprayer  33  in another embodiment. In another example, the liquid container may be provided with a valve such that the liquid collected in the liquid container may be controllably released to the downstream end of the pre-filter  44  during the backwashing step. 
     Regarding  FIGS. 5 and 6 , the backwashing step in the laundry treating appliance having both a recirculation pump and a drain pump is illustrated, according to third and fourth embodiments of the invention, respectively. In  FIG. 5 , the liquid, which is provided from the sump  16 , may be directed to the downstream end of the pre-filter  44  through the second valve  50  and third valve  52 , then pass through the pre-filter  44 , as previously described for backwash in the embodiment illustrated in  FIG. 3 . After a predetermined time period, the recirculation pump  35  may reverse the pumping direction, such that the liquid in the dye filter system  43  flows back to the sump  16  by passing through the second valve  50  set to a third position to pass the liquid from the upstream end of the pre-filter  44  to the recirculation pump  35 , and an inlet and outlet  39 ,  41  of the recirculation pump  35 . It may be understood that the inlet and outlet  39 ,  41  are coupled to the reversely operable recirculation pump  35 , therefore the inlet and outlet  39 ,  41  may work as outlet and inlet in another mode of operation. The liquid collected in the sump  16  may be provided to a drain pump  37  to be flushed out of the washing machine  10  via the drain conduit  54 . Alternatively, first valve  48  may be provided in the recirculation conduit  56  between the pre-filter  44  and the second valve  50  to direct backwash liquid from the pre-filter through a separate conduit (not shown) to the sump  16 , in which case the recirculation pump  35  need not be reversed and the second valve  50  need not be set to third position. 
     While  FIG. 5  illustrates the backwashing step using both the recirculation pump  35  and the drain pump  37 . In another embodiment, the single pump may be used instead of the recirculation pump  35  and the drain pump  37 . The single pump may be provided with the recirculation conduit  42  and the drain conduit  54  such that the liquid may not need to flow back into the sump  16  before being drained out of the washing machine  10 . For example, after the liquid is diverted to the downstream end of the pre-filter  44  and downwardly passed through the pre-filter  44 , the liquid may be directed back to the single pump, to which the drain conduit may be fluidly coupled. The liquid may be diverted from the single pump to the drain conduit without being routed to the sump  16 . 
       FIG. 6  illustrates the backwashing step of the laundry treating appliance, where the backwashing step is performed without any valves. The operation of the backwashing step may be similar to the second embodiment illustrated in  FIG. 4 , in that the backwashing step of the pre-filter  44  is performed using the reversed flow of liquid by gravity. The difference between the embodiments in  FIG. 4  and  FIG. 6  is that the embodiment in  FIG. 6  may be implemented without using any valve. 
     During the backwashing step, as illustrated in the embodiment of  FIG. 4 , when the recirculation pump  35  is turned off, the liquid flowing upwardly in the conduit  56  between the pre-filter  44  and the dye filter  46  may flow downwardly by gravity. Due to the absence of any valve in the conduit  56 , the liquid may be collected to the lower portion of the conduit  56 , and then directed to the sump  16  by the reverse operation of the recirculation pump  35 . The liquid collected in the sump  16  may be provided to the drain pump  37  to be flushed out of the washing machine  10  via the drain conduit  54 . 
     As described above for  FIG. 5 , it may be noted that the single pump may be used in replace of the recirculation pump  35  and drain pump  37  to route the liquid directly from the single pump to the drain conduit, without entering into the sump  16 . Further, it may be that the recirculation pump  35  is positioned such that gravity will direct a backflow of liquid to the sump  16  without action of the pump. 
     The invention described herein may be used in removing non-dye material from the pre-filter during the dye filtering step, before the pre-filter blocks the passage of liquid through the pre-filter. Non-dye material, which is collected by the pre-filter during the dye filtering step, may be removed from the pre-filter by backwashing the pre-filter by controllably directing the liquid to the downstream end of the pre-filter. Alternatively, the pre-filter may be backwashed by reversing the flow of liquid to the downstream end of the pre-filter by gravity. 
     To the extent not already described, the different features and structures of the various embodiments may be used in combination with each other as desired. That one feature may not be illustrated in all of the embodiments is not meant to be construed that it cannot be, but is done for brevity of description. Thus, the various features of the different embodiments may be mixed and matched as desired to form new embodiments, whether or not the new embodiments are expressly described. 
     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. Reasonable variation and modification are possible within the scope of the forgoing disclosure and drawings without departing from the spirit of the invention which is defined in the appended claims.