Patent Application
20160060800
Fatty soils such as sweat, body soils, oily soils, and fat-based greases can be difficult to remove from laundry. The low wash liquid volume and low wash liquid temperature typically used in high efficiency washing machines is generally not conducive to removing these types of fatty soils from laundry. If not removed, these fatty soils may accumulate on laundry items, eventually resulting in staining, dinginess and sometimes malodor, particularly on active or sportswear items. Some detergent compositions have attempted to address the issue of fatty soil removal by using an increase in nonionic surfactants, an optimization of the ratio of anionic to nonionic surfactants, or an increase in hydrogen peroxide bleach. However, the effectiveness of these detergent compositions are effected by the parameters of the cycle of operation in which they are used. Active and sportswear textile and garment makers have attempted to address this issue through the use of different textiles and fabric finishes, such as silver ions, chitosan, or polymer shields. While these finishes may reduce the issue of malodor generation, they do not inhibit accumulation of the fatty soils onto the item.
A laundry treating appliance and cycle of operation for treating laundry within a laundry appliance that includes a cycle of operation comprising an anti-stain setting phase and a pre-wash phase.
In the drawings:
The washing machine 10 includes a cabinet or housing 12 and an imperforate tub 14 that defines an interior 16 of the washing machine 10. A sump 18 may be in fluid communication with the interior 16 of the tub 14. A perforated wash basket or drum 20 may be located within the interior 16 and rotatable relative to the tub 14 and may define a laundry treating chamber 22 for receiving a laundry load for treatment according to an automatic cycle of operation. Rotation of the drum 20 may be considered as rotation of any items located within the treating chamber 22. The drum 20 may include a plurality of perforations or apertures 24 such that liquid supplied to the drum 20 may flow through the perforations 24 to the tub 14. An agitator or clothes mover 26 may be located within the laundry treating chamber 22 and rotatable relative to and/or with the drum 20. While the embodiments of the invention are described in the context of a washing machine having a rotatable drum located within a tub, it will be understood that the embodiments may also be used in a washing machine which has an imperforate drum without a tub.
The drum 20 and/or the clothes mover 26 may be driven by an electrical motor 28, which may or may not include a gear case, operably connected to the drum 20 and/or the clothes mover 26. The clothes mover 26 may be commonly oscillated or rotated about its axis of rotation during a cycle of operation in order to provide movement to the load contained within the laundry treating chamber 22. The drum 20 may be rotated at high speed to centrifugally extract liquid from the load and to discharge the extracted liquid from the drum 20. The top of the housing 12 may include a selectively openable lid 30 to provide access into the laundry treating chamber 22 through an open top of the drum 20.
The washing machine 10 also includes a liquid supply system for supplying water to the washing machine 10 for use in the treatment of laundry during a cycle of operation. The liquid supply system may include a source of water, such as a household water supply source 42, which may include separate valves 46, 48 for controlling the flow of hot and cold water, respectively. Water may be supplied through an inlet conduit 50 directly to the drum 20 by controlling a diverter valve 52. The diverter valve 52 may be a diverter valve having two outlets such that the diverter valve 52 may selectively direct a flow of liquid to one or both of two flow paths. Water from the household water supply source 42 may flow through the inlet conduit 50 to the diverter valve 52 which may direct the flow of liquid to an outlet conduit 54 which may be provided with a spray nozzle 56 configured to spray the flow of liquid into the drum 20. In this manner, water from the household water supply source 42 may be supplied directly to the drum 20.
The washing machine 10 may also be provided with a dispensing system for dispensing treating chemistry to the drum 20, either directly or mixed with water from the liquid supply system, for use in treating the laundry according to a cycle of operation. The dispensing system may include a dispenser 60 which may be a single use dispenser, a bulk dispenser or a combination of a single use and bulk dispenser. The dispensing system may include a dispenser which may be a single use dispenser, a bulk dispenser or a combination of a single use and bulk dispenser. Non-limiting examples of suitable dispensers are disclosed in U.S. Pat. No. 8,196,441 to Hendrickson et al., issued Jun. 12, 2012, entitled “Household Cleaning Appliance with a Dispensing System Operable Between a Single Use Dispensing System and a Bulk Dispensing System,” U.S. Pat. No. 8,388,695 to Hendrickson et al., issued Mar. 5, 2013, entitled “Apparatus and Method for Controlling Laundering Cycle by Sensing Wash Aid Concentration,” U.S. Pat. No. 8,397,328 to Hendrickson et al., issued Mar. 19, 2013, entitled “Apparatus and Method for Controlling Concentration of Wash Aid in Wash Liquid,” U.S. Pub. No. 2010/0000581 to Doyle et al., filed Jul. 1, 2008, entitled “Water Flow Paths in a Household Cleaning Appliance with Single Use and Bulk Dispensing,” U.S. Pub. No. 2010/0000264 to Luckman et al., filed Jul. 1, 2008, entitled “Method for Converting a Household Cleaning Appliance with a Non-Bulk Dispensing System to a Household Cleaning Appliance with a Bulk Dispensing System,” U.S. Pat. No. 8,397,544 to Hendrickson, issued Mar. 19, 2013, entitled “Household Cleaning Appliance with a Single Water Flow Path for Both Non-Bulk and Bulk Dispensing,” and U.S. Pat. No. 8,438,881, issued May 14, 2013, entitled “Method and Apparatus for Dispensing Treating Chemistry in a Laundry Treating Appliance,” which are herein incorporated by reference in full.
Regardless of the type of dispenser used, the dispenser 60 may be configured to dispense a treating chemistry directly to the drum 20 or mixed with water from the liquid supply system through a dispensing outlet conduit 62. The dispensing outlet conduit 62 may include a dispensing nozzle 64 configured to dispense the treating chemistry into the drum 20 in a desired pattern and under a desired amount of pressure. For example, the dispensing nozzle 64 may be configured to dispense a flow or stream of treating chemistry into the drum 20 by gravity, i.e. a non-pressurized stream. Water may be supplied to the dispenser 60 from the inlet conduit 50 by directing the diverter valve 52 to direct the flow of water to a dispensing supply conduit 66.
The washing machine 10 may also include a recirculation and drain system for recirculating liquid within the laundry holding system and draining liquid from the washing machine 10. Liquid supplied to the drum 20 through outlet conduit 54 and/or the dispensing supply conduit 66 may flow by gravity to the sump 18 through the perforations 24 provided in the side wall and bottom wall of the drum 20. The sump 18 may also be formed by a sump conduit 70 that may fluidly couple the sump 18 to a pump 72. The pump 72 may have an inlet fluidly coupled to the sump 18 and an outlet configured to fluidly couple to either or both a household drain 74, which may drain the liquid from the washing machine 10, or a recirculation conduit 76, which may terminate at a recirculation inlet 78 to re-supply the recirculated liquid to the drum 20. In this configuration, the pump 72 may be used to drain or recirculate liquid in the sump 18, which is initially sprayed into the treating chamber 22, flows through the drum 20, and then into the sump 18. Alternatively, two separate pumps may be used instead of the single pump as previously described. The recirculation inlet 78 may introduce the liquid into the drum 20 in any suitable manner, such as by spraying, dripping, or providing a steady flow of liquid. In this manner, liquid provided to the tub 14, with or without treating chemistry, may be recirculated into the treating chamber 22 for treating the laundry within.
The washing machine 10 may also be provided with a heating system (not shown) to heat liquid provided to the treating chamber 22. In one example, the heating system can include a heating element provided in the sump 18 to heat liquid that collects in the sump 18. Alternatively, the heating system may be in the form of an in-line heater that heats the liquid as it flows through the liquid supply, dispensing and/or recirculation systems.
The liquid supply, dispensing, and recirculation and drain systems may differ from the configuration shown in
Referring now to
The controller 82 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 82 may include the machine controller and a motor controller. Many known types of controllers may be used for the controller 82. The specific type of controller is not germane to the invention. It is contemplated that the controller 82 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
The controller 82 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 82 may be operably coupled with the motor 28, the pump 72, the dispensing nozzle 64, the dispenser 60, the valves 46, 48, and 52, and any other additional components that may be present such as a steam generator, and a sump heater (not shown) to control the operation of these and other components to implement one or more of the cycles of operation.
The controller 82 may also be coupled with one or more temperature sensors 92 to determine a temperature of the liquid provided by the water supply source 42, the liquid recirculated by the recirculation system, a temperature of the treating chamber 22, a temperature of liquid in the sump 18 and/or the temperature of the laundry items. The one or more temperature sensors 92 can be provided in the sump 18 or anywhere along the path of fluid flow from the water supply source 42 to the inlet conduit 50, outlet conduit 54 and through the spray nozzle 56, for example. The controller 82 may also be coupled with one or more additional sensors 94 provided in one or more of the systems of the washing machine 10 to receive input from the sensors 94, which are known in the art and not shown for simplicity. Non-limiting examples of sensors 94 that may be communicably coupled with the controller 82 include: a moisture sensor, a weight sensor, a chemical sensor, an optical sensor, a conductivity sensor, a turbidity sensor, a position sensor and a motor torque sensor, which may be used to determine a variety of system, laundry and liquid characteristics, such as laundry load inertia or mass.
The controller 82 may also be programmed to determine an amount and/or type of laundry. The amount of laundry may be qualitative or quantitative and may be determined manually based on user input through the user interface 84 or automatically by the washing machine 10 using input provided by one or more sensors according to a laundry amount determination method. A qualitative determination of the laundry amount may include determining whether the laundry is a small, medium or large load. A quantitative determination may include determining a weight or volume of the laundry within the treating chamber 22. The type of fabric may be determined based on user input, such as based on the selected cycle or one or more selected options, or automatically determined based on sensor input using any known method. The methods for determining the amount and/or type of fabric forming the laundry load are not germane to the embodiments of the invention.
The automatic cycle of operation and methods described herein also utilize an initial cold liquid treatment prior to the pre-wash phase to minimize the setting of protein-based stains. Applicants have found that while the high liquid temperatures facilitate the removal of fatty soils, those same high liquid temperatures may set some protein-based soils, such as blood, for example, resulting in the formation of protein-based stains that are difficult, if not impossible to remove without damaging the laundry item. Thus, the cycle of operation and methods described herein include an initial anti-stain setting phase prior to treatment of the laundry at high temperatures in the hot pre-wash phase to minimize setting protein-based soils, while still facilitating the removal of fatty-based soils from the laundry.
As used herein, a pre-wash phase refers to a phase, prior to the main wash phase, in which the laundry is treated with a treating chemistry according to different operating parameters than the main wash phase. Non-limiting examples of operating parameters that may vary between the pre-wash phase and the main wash phase include a temperature of the wash liquid, a concentration of a treating chemistry in the wash liquid, a volume of the wash liquid, a duration of the phase, an amount and/or type of mechanical energy imparted to the laundry, and combinations thereof. In the exemplary cycle described below, the pre-wash phase is implemented using a higher temperature wash liquid, a higher concentration of treating chemistry, a lower volume of wash liquid than the main wash phase. In addition an amount of mechanical energy imparted during the pre-wash phase may be lower than that imparted during the main wash phase, as well as the manner in which the mechanical energy is imparted may differ between the pre-wash and main phases. For example, mechanical energy may be imparted to the load by rotating the drum 20 according to a predetermined rotation profile, actuating the clothes mover 26, and/or recirculation the liquid.
The sequence of steps depicted for the cycle of operation and the subsequent methods are for illustrative purposes only, and are not meant to limit any of the cycles or methods 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 cycle of operation 100 begins with assuming that a user has placed laundry items for treatment into the drum 20 and selected the cycle of operation. The cycle of operation 100 may begin at 101 with an anti-stain setting phase in which the laundry is treated with cold water that does not include detergent. The cycle of operation 100 then proceeds to a pre-wash phase 102 in which the laundry is treated with a low volume of a hot pre-wash liquid that includes a detergent composition that includes at least one detergent at a higher concentration than used in a main wash phase 104. At 104, additional water from the water supply source 42 is supplied to the tub 14 to increase the volume of wash liquid to a main wash fill level and to decrease the concentration of the detergent composition to a main wash phase concentration to form a main wash liquid. The main wash phase 104 may also include treatment of the laundry with additional treating chemistries. An extraction and/or drain phase may be implemented at 106 in which wash liquid collected in the sump 18 is drained from the treating chamber 22 and an optional extraction phase in which the laundry is rotated to facilitate the extraction of liquid from the laundry, which may subsequently be drained from the sump 18. A rinse phase in which fresh liquid from the water supply source 42 is supplied to the laundry, and optionally recirculated onto the laundry, one or more times, may be implemented at 108 to remove the wash liquid and soil/debris from the laundry. The rinse phase 108 may also include treatment of the laundry with additional treating chemistries, such as a rinse aid or fabric softener, for example. An additional extraction and/or drain phase 110 may be implemented prior to completing the cycle at 112.
The amount of liquid supplied to the washing machine 10 during any of the anti-stain setting phase 101, pre-wash phase 102 and the main wash phase 104 may be determined according to any suitable method and the method used during one of the phases 101, 102 and 104 may be different than the method used during the other phases. In one example, the amount of supplied liquid may be determined using one or more liquid level sensors provided in the tub 14 and/or sump 18. Non-limiting examples of liquid level sensors include pressure sensors and optical sensors.
Alternatively, the amount of supplied liquid may be determined according to a time-based method based on an amount of time the hot or cold water valves 46 and 48 are open and a flow rate of water supplied from each. The washing machine 10 may be provided with a liquid flow sensor that is operably coupled with the controller 82 to provide flow rate information to the controller 82 for determining an amount of liquid supplied based on the amount of time the hot or cold water valves 46, 48 are open. In another example, the washing machine 10 may be provided with a flow rate limiter that limits the flow of water from the water supply source 42 to a predetermined flow rate. The controller 82 may then use this predetermined flow rate and the amount of time the hot or cold water valves 46, 48 are open to determine the amount of liquid supplied.
A time-based method for determining an amount of supplied liquid may be particularly useful during phases in which the amount of liquid supplied may not be sufficient for use with a liquid level sensor provided in the tub/sump area. For example, the anti-stain setting phase 101 uses low liquid volumes which may not be sufficient for measurement using a traditional liquid level pressure sensor in the sump. In washing machines in which the liquid is supplied directly to the treating chamber rather than into the tub, the supplied liquid during the low volume anti-stain setting phase 101 may be completely absorbed by the laundry and little to no liquid may collect in the sump.
In an exemplary embodiment, the cycle of operation 100 corresponds to an active or sportswear cycle. The user interface 84 may be configured to provide the user with the ability to select the active or sportswear cycle. Active or sportswear typically include instructions to wash the items in cold or warm water. In the exemplary embodiment, when the active or sportswear cycle is selected by the user, the main wash phase 104 may be configured to wash the laundry in cold or warm water and automatically treat the laundry according to anti-stain setting phase 101 and pre-wash phase 102.
The predetermined amount of anti-stain setting liquid formed at 202 may be an amount which wets or dampens the laundry load without overly saturating the load and may be based on an amount and/or type of fabric forming the laundry load, characteristics of the specific washing machine implementing the cycle, and/or a predetermined time period. Adding too much cold liquid at 202 may increase the amount of hot liquid needed to reach the desired temperature in the next stage in the cycle, which may undesirably increase the length of the cycle. The amount of anti-stain setting liquid may be determined by the controller 82 using pre-programmed algorithms or stored look-up tables relating the amount of anti-stain setting liquid to one or more characteristics of the laundry, such as an amount of fabric type, the selected cycle of operation, and/or the specific machine implementing the cycle. Generally, the amount of anti-stain setting liquid supplied at 202 is in the range of 2-8 liters, and may vary depending on the type and/or amount of laundry and characteristics of the washing machine, such as the dimensions of the tub, drum and/or sump. An illustrative amount of anti-stain setting liquid for a 3.6 kg standard 100% cotton load is 4 liters of cold water. The standard load is based on the standards set forth in the Association of Home Appliance Manufacturers (AHAM) “Performance Evaluation Procedures for Household Clothes Washers” AHAM HLW-1-2010.
In one example, the volume of anti-stain setting liquid may be based on satisfying a predetermined liquid to laundry ratio (e.g. kilograms of liquid per kilogram of laundry). As used herein, liquid to laundry ratio refers to the ratio of all the liquid in the washing machine (including free liquid in the drum 20, liquid absorbed by the laundry, and free liquid within the tub 14 and sump 18) to the total laundry amount. For example, the anti-stain setting liquid may be supplied to provide a liquid to laundry ratio in the range of 0.5-2.2. The amount of anti-stain setting liquid may be determined by the controller 82 using pre-programmed algorithms or stored look-up tables relating an amount of laundry to an amount of anti-stain setting liquid based on satisfying a predetermined liquid to laundry ratio.
Alternatively, the amount of anti-stain setting liquid may correspond to a predetermined default amount. For example, the default amount may correspond to an amount that is sufficient to wet an average load for a particular machine and/or cycle. The default amount may be determined empirically based on average load size and an amount of anti-stain setting liquid that provides the desired anti-stain setting properties a predetermined proportion of the time (e.g. 75% of the time).
The temperature of the cold anti-stain setting liquid formed at 202 may be within a range of 60-86° F. As of the filing of this application, the United States Federal Trade Commission defines “cold water” as used for fabric care labels as having a temperature less than 86° F. In a preferred embodiment, the anti-stain setting liquid may be within a range of about 60-80° F. and more preferably about 60° F.
At 204, the cold anti-stain setting liquid can be supplied directly to the laundry through the spray nozzle 56 and may optionally be recirculated onto the laundry to facilitate evenly wetting the laundry. The drum 20 may be rotated to and the clothes mover 26 may optionally be activated to agitate the laundry to facilitate evenly wetting the laundry. In an exemplary cycle, the drum 20 may be rotated at low speed, e.g. 0-40 rpm, to distribute the anti-stain setting liquid onto the laundry. In another example, the motor 28 may be alternately turned “on” and “off” to facilitate uniform wetting of the laundry.
An optional extraction and/or drain stage may be implemented during the transition from the anti-stain setting phase 101 to the pre-wash phase 102 to extract and/or drain any liquid that may have collected in the sump 18 during the supply of cold anti-stain setting liquid to the laundry at 202. Typically, a drain stage will not be necessary, as the amount of cold liquid is preferably selected so as to not over saturate the laundry such that liquid runs off the laundry and collects in the sump 18. Cold liquid collected within the sump 18 may increase an amount of hot liquid and/or an amount of time needed to form the hot pre-wash liquid at the next stage 206, and thus a drain stage may be implemented to drain any cold liquid from the sump 18.
Subsequent to the anti-stain setting phase 101, at 206 a hot pre-wash liquid comprising a mixture of hot water and a detergent composition is formed. The hot pre-wash liquid may be formed such that a temperature of the liquid satisfies a first temperature threshold. Satisfying the first temperature threshold may include comparing a determined temperature of the pre-wash liquid to a predetermined reference value that may be a range of reference values, an upper threshold or a lower threshold stored in the memory 88 of the controller 82. The term “satisfies” the threshold is used herein to mean that the variation satisfies the predetermined threshold, such as being equal to, less than, or greater than the threshold value. It will be understood that such a determination may easily be altered to be satisfied by a positive/negative comparison or a true/false comparison. For example, a less than threshold value can easily be satisfied by applying a greater than test when the data is numerically inverted. The temperature of the pre-wash liquid may be determined using the temperature sensor 92 which outputs a value indicative of the temperature of the wash liquid to the controller 82.
In one example, the first temperature threshold may be satisfied when the pre-wash liquid temperature is within a range of 95-115° F., inclusive of end points. In another example, the first temperature threshold may be satisfied when the pre-wash liquid temperature is at least 98° F. Many of the fatty soils that may be deposited on laundry, such as sweat, body soils, and greases, have a melting or softening temperature in the range of mammalian body temperature of 90-105° F. As described above, treating the laundry with a pre-wash liquid heated to within a specific range to melt or soften the fatty soils may facilitate lifting the soils from the laundry.
Forming the hot pre-wash liquid at 206 may include controlling the hot water valve 46 of the water supply source 42 to supply hot water to the washing machine 10 and/or heating liquid supplied to the washing machine 10 using an internal heating system within the washing machine 10. Some washing machines may only be connected with a supply of cold water and thus an internal heating system, such as a sump heater, may be used to heat the liquid to satisfy the first temperature threshold. Alternatively, some washing machines may not include an internal heating system and thus the only source of hot water is an externally heated water supply. In another example, externally heated water supplied to the washing machine 10 may further be heated using an internal heating system to more quickly increase the temperature of the liquid to satisfy the first temperature threshold. The detergent composition may be provided at any point before, during or after the temperature of the water satisfies the first temperature threshold.
The volume of hot pre-wash liquid may correspond to a tub fill level that is less than a tub fill level used during the main wash phase 104. In this manner the laundry is treated with the detergent composition at a higher concentration than during the main wash phase 104. The pre-wash tub fill level may be determined by the controller 82 using pre-programmed algorithms or stored look-up tables relating the fill level to one or more characteristics of the laundry, the selected cycle of operation, and/or the specific machine implementing the cycle. Generally, the pre-wash tub fill level is in the range of 8-18 liters, and may vary depending on the type and/or amount of laundry and characteristics of the washing machine, such as the dimensions of the tub, drum and/or sump. An illustrative amount of hot pre-wash liquid for a 3.6 kg AHAM standard 100% cotton load is 16 liters.
In one example, the volume of hot pre-wash liquid may be based on satisfying a predetermined liquid to laundry ratio (e.g. kilograms of liquid per kilogram of laundry) that corresponds to a low volume pre-wash fill level. For example, the volume of hot pre-wash liquid may correspond to a liquid to laundry ratio greater than 0 and less than or equal to 5, preferably in the range of 2.2 to 5. In another example, the volume of the hot pre-wash liquid may correspond to a fill level that partially immerses or fully submerges the laundry. Alternatively, the fill level may correspond to a level that does not contact the laundry such that the laundry is only wet by recirculation of the liquid onto the laundry.
Additionally, or alternatively, the volume of hot pre-wash liquid may correspond to a volume of liquid which provides a concentration of the detergent composition within a range of 1.5 to 4.5 times the concentration of the detergent composition during the main wash phase 104, preferably 1.5 to 2 times the concentration of the detergent composition during the main wash phase 104. The tub fill level for the pre-wash phase 102 and/or main wash phase 104 may be based on the load amount and/or type, which may be determined as described above at 202.
Additionally, or alternatively, for a washing machine connected with a supply of externally heated water, the volume of hot pre-wash liquid may be based on supplying the externally heated water to the tub 14 until a temperature of the wash liquid in the tub 14 satisfies the first temperature threshold. In this scenario, a temperature sensor 92 may be configured to determine a temperature of the liquid collecting in the tub 14 and the controller 82 may be configured to stop the supply of liquid when the liquid in the tub 14 satisfies the first predetermined temperature threshold.
At 208 the laundry load may be moved through the hot pre-wash liquid to facilitate treatment of the laundry load with the pre-wash liquid. Moving the laundry through the hot pre-wash liquid may include recirculating the pre-wash liquid collected in the tub 14 through the recirculation system and/or rotating the drum 20. Alternatively, or additionally, the clothes mover 26 can be actuated to move the laundry load through the pre-wash liquid to facilitate treating the laundry with the pre-wash liquid. When the volume of pre-wash liquid is such that the laundry is partially immersed or fully submerged in the pre-wash liquid, rotation of the drum 20 and actuation of the clothes mover 26 may be used to facilitate treating the laundry with the pre-wash liquid. Recirculation of the pre-wash liquid may be utilized to further facilitate treating the laundry with the pre-wash liquid. When the volume of pre-wash liquid is such that the fill level is below a level which contacts the laundry, recirculation may be used to treat the laundry with the pre-wash liquid and rotation of the drum 20 and actuation of the clothes mover 26 may optionally be used to move the laundry to facilitate evenly treating the laundry. Rotation of the drum 20 and actuation of the clothes mover 26 may also impart mechanical action to the laundry to facilitate lifting soils from the laundry. The laundry load may be moved through the pre-wash liquid for a predetermined period time to soften and melt fatty based soils present on the laundry to facilitate lifting of the soils by the detergent composition. However, it may be beneficial to minimize prolonged exposure to hot liquid in a temperature range of 95-115° F. to avoid damaging the laundry fabric. In one example, the laundry may be moved through the hot pre-wash liquid for a period of 2 to 10 minutes.
Still referring to
In one exemplary embodiment, the controller 82 controls the cold water valve 48 to supply cold water to the tub 14 to form a main wash liquid having a temperature less than the temperature of the pre-wash liquid during the pre-wash phase 102. A preferred temperature range for the main wash liquid is in the range of 60-95° F., although the temperature may vary depending on the selected cycle of operation, the volume of water added and the temperature of the water added. The temperature of the wash liquid may be monitored using the temperature sensor 92 and the volume and temperature of the added water may be controlled by the controller 82 such that the temperature of the main wash liquid when the main wash fill level is reached satisfies a predetermined temperature threshold. Alternatively, cold water may be added to the tub 14 to reach the main wash fill level with the assumption that the temperature of the main wash liquid at the main wash fill level satisfies a predetermined temperature threshold, such as below 95° F., for example.
In most scenarios, because of the high temperature of the hot pre-wash liquid, only cold water will be supplied to the tub 14 to reach the main wash fill level and decrease the temperature of the wash liquid to a temperature suitable for the main wash phase 104. However, it is within the scope of the invention for both hot and cold water to be added to the tub 14 to form the main wash liquid having a desired temperature at 210.
The increase in volume from the pre-wash fill level to the main wash fill level decreases the concentration of the detergent composition, and any additional treating chemistries that may have been added prior to or during the pre-wash phase 102. The amount of detergent composition supplied during the pre-wash phase 102 may have been selected at least in part to provide a predetermined concentration of the detergent composition during the main wash phase 104. Depending on the amount of liquid added to form the main wash liquid, additional detergent composition may be added to provide the main wash liquid with the desired concentration of the of the detergent composition during the main wash phase 104. Additional detergent and other treating chemistries may also be added during the main wash phase 104 depending on the selected cycle of operation.
At 212, the laundry load may be moved through the main wash liquid to facilitate treatment of the laundry load with the main wash liquid. Moving the laundry through the main wash liquid may include recirculating the main wash liquid in the tub 14 through the recirculation system and/or rotating the drum 20. Alternatively, or additionally, the clothes mover 26 may be actuated to move the laundry load through the wash liquid to facilitate treating the laundry with the wash liquid. When the volume of wash liquid is such that the laundry is partially immersed or fully submerged in the wash liquid, rotation of the drum 20 and actuation of the clothes mover 26 may be used to facilitate treating the laundry with the wash liquid. Recirculation of the wash liquid may be utilized to further facilitate treating the laundry with the wash liquid. When the volume of wash liquid is such that the fill level is below a level which contacts the laundry, recirculation may be used to treat the laundry with the wash liquid and rotation of the drum 20 and actuation of the clothes mover 26 may optionally be used to move the laundry to facilitate evenly treating the laundry. Rotation of the drum 20 and actuation of the clothes mover 26 may also be used to impart mechanical action to the laundry to facilitate lifting soils from the laundry. At 214, the cycle may continue on to the remaining phases of the cycle.
Table 1 illustrates an exemplary cycle of operation for a 3.6 kg AHAM 100% cotton load treated according to the cycle of operation 100 and method 200 of
Referring now to
Still referring to
If the temperature of the wash liquid satisfies the second temperature threshold at 306, the method may proceed at “A” to 206 of the method 200 of
Preferably the amount of time it takes to form the hot pre-wash liquid is minimized, as it is generally not desirable to lengthen a cycle of operation any more than is necessary to provide the desired laundry treatment. During the anti-stain setting phase 101, cold water from the water supply source 42 is supplied to the laundry, which may result in cold water remaining in a path between the spray nozzle 56 and the cold water valve 48. The cold water remaining in this path will be supplied into the tub 14 when the hot water valve 46 is opened. Depending on the amount and temperature of the cold water in this path, the cold water may undesirably increase the time and amount of hot water that needs to be supplied to form the hot pre-wash liquid at a temperature that satisfies the first predetermined temperature threshold. The method 300 may be used to purge this cold water from the system prior to adding hot water to avoid unnecessarily lengthening the cycle or increasing the volume of the pre-wash liquid.
The second predetermined temperature threshold at 306 may be the same as the first predetermined temperature threshold at 206 of the method 200 of
The threshold for the number of drain cycles at 308 may be set at any desired number such that the method 300 is only repeated a predetermined number of times before the cycle continues onto the next phase or stage so as to not extend the length of the cycle more than a desired amount.
During the supply of hot liquid at 302, the liquid is preferably added to the tub 14 without contacting the laundry. In this manner, if the temperature of the supplied liquid is lower than desired, the low temperature liquid does not contact the laundry, which may increase the time and energy required to form the hot pre-wash liquid to melt and/or soften the fatty soils. Some washing machines supply the water from the water supply source 42 directly to the tub 14. However, for washing machines in which the water is supplied into the drum 20, such as illustrated for the washing machine 10 of
The cycle and methods for implementing the cycle described herein provide a method for removing fatty soils from laundry that may be difficult to remove, especially in high efficiency washing machines which use low fill levels and low liquid temperatures as well as on laundry which typically includes instructions to wash at low temperatures, such as active or sportswear. The embodiments described herein utilize a hot pre-wash liquid at temperatures that may melt or soften many of these fatty soils to facilitate lifting the soils from the laundry by a detergent composition, which is present at a higher concentration in the pre-wash liquid than used during a typical wash phase to further facilitate lifting the soils from the laundry.
However, as discussed above, hot liquid, particularly in the temperature ranges according to the embodiments of the invention that melt/soften fatty soils, may set some protein-based stains, such as blood, which make these stains difficult, if not impossible to remove. A protein in its native 3-D shape will have hydrophobic amino acids hidden within the structure of the protein and hydrophilic amino acids on the outside, enabling the protein to be soluble in water. When denatured, the bonds holding the amino acids together are disrupted and the protein loses its 3-D structure and so some hydrophobic amino acids may become exposed on the surface of the structure, decreasing the water solubility of the protein. Decreasing the water solubility of the protein may result in the protein precipitating out of solution, but in some cases, depending on the nature of the fabric, may actually result in an increase in the interaction between the denatured protein and the fabric. Fabrics having a hydrophobic component, such as polyester and other synthetics, which are often used in active and sportswear, may interact with the exposed hydrophobic amino acids, inhibiting removal of the protein from the fabric surface. The embodiments of the invention described herein provide a method for facilitating the removal of fatty soils without undesirably diminishing the ability to remove protein-based stains.
The embodiments of the invention may be used with an active or sportswear cycle to facilitate removal of fatty soils from active or sportswear items, especially those made using synthetic materials. Most active or sportswear cycles are designed to wash the items in cold or warm water, with gentle agitation, and in the case of high efficiency washers, low fill volume. These parameters—cold/warm water, gentle agitation, and low volume—are generally not efficient in lifting fatty stains. The cycle and methods described herein provide a hot, low volume, concentrated detergent pre-wash phase which facilitates removal of fatty stains that may be combined with a main wash phase configured to wash the laundry in accordance with typical active/sportswear wash instructions, while at the same time providing an anti-stain setting phase minimize setting stains during the hot pre-wash phase.
To the extent not already described, the different features and structures of the various embodiments of the invention may be used in combination with each other as desired. For example, one or more of the features illustrated and/or described with respect to one of the cycles or methods 100, 200 or 300, can be used with or combined with one or more features illustrated and/or described with respect to the other of the cycles or methods 100, 200 or 300. 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.
