METHOD OF SANITIZATION IN A LAUNDRY TREATING APPLIANCE

Abstract

A method of operating a laundry treating appliance having a rotatable drum for at least partially defining a treating chamber and for holding laundry, for substantially removing bacteria from laundry received in the interior of the drum without energizing a heating element of the laundry treating appliance, according to a predetermined sanitization cycle of operation.

Description

BACKGROUND

Laundry treating appliances, such as clothes washers, may implement a sanitization cycle for sanitizing and disinfecting laundry articles placed in a rotatable drum that defines a treating chamber in which laundry items are placed for treating. The sanitization cycle may typically be implemented by heating the liquid and/or laundry articles in the treating chamber using at least one of a heating element or a steam generator above a threshold temperature to effectively remove bacteria, allergen, dust or other bio-substances from laundry items. The sanitization cycle employing the heating element or steam generator may require substantial amount of time until completion. Further, the operation of the heating element or steam generator may necessarily require a considerable amount of energy and water consumption.

BRIEF SUMMARY

According to an embodiment of the invention, a method of substantially removing bacteria from laundry in a laundry treating chamber of a washing machine without using a heating element, comprises adding first hot water to a first predetermined level in the laundry treating chamber at a first predetermined temperature; dispensing a mixture of stain removing agent and detergent to the water in the laundry treating chamber; tumbling the laundry in the hot water for a first predetermined time; adding second hot water to a second predetermined level in the laundry treating chamber; tumbling the laundry in the hot water for a second predetermined time; adding first cold water in stepped increments to the hot water, tumbling the laundry for a third predetermined time; and adding second cold water to a fourth predetermined level in the laundry treating chamber, tumbling the laundry for a fourth predetermined time.

BRIEF DESCRIPTION OF THE DRAWINGS

In the drawings:

FIG. 1 is a schematic view of a laundry treating appliance in the form of a washing machine according to one embodiment of the invention.

FIG. 2 is a schematic of a control system of the laundry treating appliance of FIG. 1.

FIGS. 3A-3D are a schematic illustration of a sanitization cycle for laundry articles in the washing machine according to one embodiment of the invention, wherein hot/cold water supplies, a water level, a sump temperature and a drum speed are illustrated with respect to elapsed time in FIGS. 3A, 3B, 3C and 3D, respectively.

FIG. 4 is a flow chart illustrating a method of sanitizing laundry articles in a treating chamber of the washing machine according to one embodiment of the invention.

DETAILED DESCRIPTION

FIG. 1 is a schematic view of a laundry treating appliance according to one embodiment of the invention. The laundry treating appliance may be any appliance which performs a cycle of operation to clean or otherwise treat items placed therein, non-limiting examples of which include a horizontal or vertical axis clothes washer; a combination washing machine and dryer; a tumbling or stationary refreshing/revitalizing machine; an extractor; a non-aqueous washing apparatus; and a revitalizing machine.

The laundry treating appliance of FIG. 1 is illustrated as a washing machine 10, which may include a structural support system comprising a cabinet 12 which defines a housing within which a laundry holding system resides. The cabinet 12 may be a housing having a chassis and/or a frame, defining an interior that encloses components typically found in a conventional washing machine, such as motors, pumps, fluid lines, controls, sensors, transducers, and the like. Such components will not be described further herein except as necessary for a complete understanding of the invention.

The laundry holding system comprises a tub 14 supported within the cabinet 12 by a suitable suspension system and a drum 16 provided within the tub 14, the drum 16 defining at least a portion of a laundry treating chamber 18. The drum 16 may include a plurality of perforations 20 such that liquid may flow between the tub 14 and the drum 16 through the perforations 20. A plurality of devices 22 may be disposed on an inner surface of the drum 16 to impact the movement and distribution of wash loads, water and treating chemistries, or any other material present in the interior of the drum 16 in the treating chamber 18 while the drum 16 rotates. It is also within the scope of the invention for the laundry holding system to comprise only a tub with the tub defining the laundry treating chamber.

The laundry holding system may further include a door 24 which may be movably mounted to the cabinet 12 to selectively close both the tub 14 and the drum 16. A bellows 26 may couple an open face of the tub 14 with the cabinet 12, with the door 24 sealing against the bellows 26 when the door 24 closes the tub 14.

The washing machine 10 may further include a suspension system 28 for dynamically suspending the laundry holding system within the structural support system.

The washing machine 10 may further include a liquid supply system for supplying water to the washing machine 10 for use in treating laundry during a cycle of operation. The liquid supply system may include a source of water, such as a household water supply 40, which may include separate valves, such as hot water valve 42 and cold water valve 44 for controlling the flow of hot and cold water, respectively. Water may be supplied through an inlet conduit 46 directly to the tub 14 by controlling first and second diverter mechanisms 48 and 50, respectively. The diverter mechanisms 48, 50 may be a diverter valve having two outlets such that the diverter mechanisms 48, 50 may selectively direct a flow of liquid to one or both of two flow paths. Water from the household water supply 40 may flow through the inlet conduit 46 to the first diverter mechanism 48 which may direct the flow of liquid to a supply conduit 52. The second diverter mechanism 50 on the supply conduit 52 may direct the flow of liquid to a tub outlet conduit 54 which may be provided with a spray nozzle 56 configured to spray the flow of liquid into the tub 14. In this manner, water from the household water supply 40 may be supplied directly to the tub 14.

The washing machine 10 may also be provided with a dispensing system for dispensing treating chemistry to the treating chamber 18 for use in treating the laundry according to a cycle of operation. The dispensing system may include a dispenser 62 which may be a single use dispenser, a bulk dispenser or a combination of a single and bulk dispenser. Non-limiting examples of suitable dispensers are disclosed in U.S. Pub. No. 2010/0000022 to Hendrickson et al., filed Jul. 1, 2008, entitled “Household Cleaning Appliance with a Dispensing System Operable Between a Single Use Dispensing System and a Bulk Dispensing System,” U.S. Pub. No. 2010/0000024 to Hendrickson et al., filed Jul. 1, 2008, entitled “Apparatus and Method for Controlling Laundering Cycle by Sensing Wash Aid Concentration,” U.S. Pub. No. 2010/0000573 to Hendrickson et al., filed Jul. 1, 2008, 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. Pub. No. 2010/0000586 to Hendrickson, filed Jun. 23, 2009, entitled “Household Cleaning Appliance with a Single Water Flow Path for Both Non-Bulk and Bulk Dispensing,” and application Ser. No. 13/093,132, filed Apr. 25, 2011, 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 62 may be configured to dispense a treating chemistry directly to the tub 14 or mixed with water from the liquid supply system through a dispensing outlet conduit 64. The dispensing outlet conduit 64 may include a dispensing nozzle 66 configured to dispense the treating chemistry into the tub 14 in a desired pattern and under a desired amount of pressure. For example, the dispensing nozzle 66 may be configured to dispense a flow or stream of treating chemistry into the tub 14 by gravity, i.e. a non-pressurized stream. In another example, water may be dispensed from the dispenser 62 into the tub 14 through a rear dispenser outlet conduit 67, which may be provided with a dispensing nozzle 69. Water may be supplied to the dispenser 62 from the supply conduit 52 by directing the diverter mechanism 50 to direct the flow of water to a dispensing supply conduit 68.

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, 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 treating chemistries may be in the form of a liquid or a solid such as powders, granules, or pods.

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 tub 14 through tub outlet conduit 54 and/or dispensing supply conduit 68 typically enters a space between the tub 14 and the drum 16 and may flow by gravity to a sump 70 formed in part by a lower portion of the tub 14. The sump 70 may also be formed by a sump conduit 72 that may fluidly couple the lower portion of the tub 14 to a pump 74. The pump 74 may direct liquid to a drain conduit 76, which may drain the liquid from the washing machine 10, or to a recirculation conduit 78, which may terminate at a recirculation inlet 80. The recirculation inlet 80 may direct the liquid from the recirculation conduit 78 into the drum 16. The recirculation inlet 80 may introduce the liquid into the drum 16 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 18 for treating the laundry within.

The liquid supply and/or recirculation and drain system may be provided with a heating system which may include one or more devices for heating laundry and/or liquid supplied to the tub 14, such as a steam generator 82 and/or a sump heater 84. Liquid from the household water supply 40 may be provided to the steam generator 82 through the inlet conduit 46 by controlling the first diverter mechanism 48 to direct the flow of liquid to a steam supply conduit 86. Steam generated by the steam generator 82 may be supplied to the tub 14 through a steam outlet conduit 87. The steam generator 82 may be any suitable type of steam generator such as a flow through steam generator or a tank-type steam generator. Alternatively, the sump heater 84 may be used to generate steam in place of or in addition to the steam generator 82. In addition or alternatively to generating steam, the steam generator 82 and/or sump heater 84 may be used to heat the laundry and/or liquid within the tub 14 as part of a cycle of operation.

Additionally, the liquid supply and recirculation and drain system may differ from the configuration shown in FIG. 1, such as by inclusion of other valves, conduits, treating chemistry dispensers, sensors, such as water level sensors and temperature sensors, and the like, to control the flow of liquid through the washing machine 10 and for the introduction of more than one type of treating chemistry. As well, liquid may be supplied from the bottom where it is not filled into the drum directly onto a load, but into the sump. The load would get exposed to the water by the water level rising from the bottom, penetrating the drum starting at its lowest point.

The washing machine 10 also includes a drive system for rotating the drum 16 within the tub 14. The drive system may include a motor 88, which may be directly coupled with the drum 16 through a drive shaft 90 to rotate the drum 14 about a rotational axis during a cycle of operation. The motor 88 may be a brushless permanent magnet (BPM) motor having a stator 92 and a rotor 94. Alternately, the motor 88 may be coupled to the drum 16 through a belt and a drive shaft to rotate the drum 16, as is known in the art. Other motors, such as an induction motor or a permanent split capacitor (PSC) motor, may also be used. The motor 88 may rotate the drum 16 at various speeds in either rotational direction.

The washing machine 10 also includes a control system for controlling the operation of the washing machine 10 to implement one or more cycles of operation. The control system may include a controller 96 located within the cabinet 12 and a user interface 98 that is operably coupled with the controller 96. The user interface 98 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. A user may enter different types of information including, without limitation, cycle selection and cycle parameters, such as cycle options.

The controller 96 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 96 may include the machine controller and a motor controller. Many known types of controllers may be used for the controller 96. The specific type of controller is not germane to the invention. It is contemplated that the controller 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 96 may be provided with a memory 100 and a central processing unit (CPU) 102. The memory 100 may be used for storing the control software that is executed by the CPU 102 in completing 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. The memory 100 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 96. The database or table may be used to store the various operating parameters for the one or more 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 96 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 96 may be operably coupled with the motor 88, the pump 74, the dispenser 62, the steam generator 82 and the sump heater 84 to control the operation of these and other components to implement one or more of the cycles of operation.

The controller 96 may also be coupled with one or more sensors 104 provided in one or more of the systems of the washing machine 10 to receive input from the sensors, which are known in the art and not shown for simplicity. Non-limiting examples of sensors 104 that may be communicably coupled with the controller 96 include: a treating chamber temperature sensor, a pressure sensor for determining water level in the treating chamber 18, a moisture sensor, a weight sensor, a chemical sensor, a position sensor and a motor torque sensor, which may be used to determine a variety of system and laundry characteristics, such as laundry load inertia or mass.

The laundry articles to be treated in the treating chamber 18 may be contaminated by bacteria, allergens or other bio-substances, and may need to be treated under a sanitization cycle to eliminate or neutralize the bacteria, allergens or other bio-substances. Typically the sanitization cycle may be implemented by providing steam to the contaminated laundry items in the treating chamber 18 using the steam generator 82 or the sump heater 84. The operation of the steam generator 82 or sump heater 84 may necessitate additional energy consumption and extended sanitization cycle time, which may result in consumer dissatisfaction.

The present invention addresses the problem of consuming additional energy and unnecessarily long sanitization cycle time caused by heating the wash liquid by means of the steam generator 82 or a heating element in the form of a sump heater 84. The embodiments of the invention address the problem by supplying two, time-spaced charges of hot water from the hot water valve 42, supplying a mixture of treating chemistries, followed by supplying two or more charges of cold water from the cold water valve 44, with controlled drum rotation for tumbling laundry, without using the steam generator 82 or the sump heater 84.

Referring now to FIGS. 3A, 3B, 3C and 3D, schematics of a sanitization cycle for laundry items in the washing machine 10 according to one embodiment of the invention are illustrated, where hot/cold water supplies, a water level, a sump temperature and the drum speed are illustrated with respect to the cycle time, in FIGS. 3A, 3B, 3C and 3D, respectively.

Prior to the onset of the sanitization cycle, the laundry articles to be sanitized may be received in the treating chamber 18. It may be noted that, in the present invention of sanitization cycle, hot water supply may comprise two, time-spaced charges of hot water from the hot water valve 42. As illustrated in FIG. 3A, a first charge of hot water may be supplied from the hot water valve 42 into the treating chamber 18 until the volume of water added to the treating chamber 18 ranges approximately between 18 and 22 liters. Alternatively, the amount of the first charge of hot water may be determined by monitoring the sensor output of the pressure sensor. For example, as illustrated in FIG. 3B, the first charge of hot water may be supplied until a first water level 310, determined by the pressure sensor, reaches approximately 60 mmWC. The hot water temperature may be controlled such that the sump temperature 320, i.e., the water temperature measured at the sump 74, may range between 42 and 45 degrees Celcius (° C.), as illustrated in FIG. 3C.

A mixture of two different treating chemistries may be dispensed to the first charge of hot water supplied to the treating chamber 18. The mixture may include a stain removing agent and a detergent. In one example, OxiClean® powder and Tide® HE liquid may be used as stain removing agent and detergent, respectively, for the sanitization cycle of the present invention. Other stain removing agents and detergents may also be used for the sanitization cycle.

By “mixture,” it is meant that both the stain removing agent and the detergent may be supplied to the treating chamber 18 and mixed with each other in the treating chamber 18 for sanitizing laundry during the sanitization cycle. By “mixture,” it is not necessarily meant that both stain removing agent and detergent are physically or chemically mixed in the dispenser before being dispensed into the treating chamber 18. Therefore, for example, a powder-type stain removing agent may be supplied to the laundry articles in the treating chamber 18 prior to the onset of the sanitization cycle, and a liquid-type detergent may be mixed with the water supply, and then dispensed from the dispenser 62 into the treating chamber 18 to be mixed with the stain removing agent, which is already present in the treating chamber. In another embodiment, the stain removing agent and detergent may be separately dispensed into the treating chamber 18 from the detergent dispenser 62.

The mixture of stain removing agent and detergent may comprise about 1.3 parts of the stain removing agent by weight and about 1.0 part of detergent by volume. The amount of the mixture may be determined based on the laundry size. In one example, the weight of the stain removing agent may be designed to be about 1.3-1.5% of the laundry weight.

After the stain removing agent and detergent are supplied to the treating chamber 18, the laundry may be tumbled in the rotating drum 16, rotating at a low speed for a predetermined time in a first tumbling step 330 as show in FIG. 3D. In one example, the laundry articles received in the drum 16 may be tumbled for about 25-35 minutes at or below 100 rpm for uniformly dissolving the mixture in the hot water, and for uniformly exposing the dissolved mixture to laundry articles for sanitization. The time for the tumbling step may vary depending on the degree of soil in the laundry. Typically longer tumbling time may be required for heavily soiled laundry. During the first tumbling step 330, due to the heat transfer between wash liquid and treating chamber 18 with respect to time, the water temperature may decline by 3-4° C. at the end of first tumbling step 330 and the sump temperature 322 may be in a range of 38-42° C.

A second charge of hot water 302 may subsequently be supplied from the hot water valve 42 into the treating chamber 18 for compensating the heat energy loss during the first tumbling step 330. The second charge of hot water 302 may typically be supplied to the treating chamber 18 once the first tumbling step 330 is complete. Alternately, the supply of the second charge of hot water 302 may be initiated when the first charge of hot water 300 cools down to satisfy a predetermined threshold temperature.

The second charge of hot water 302 may be added by approximately 6 liters to the first charge of hot water 300, which is already present in the treating chamber 18. Alternately, the second charge of hot water 302 may be added to the treating chamber until a second water level 312 achieves a pressure of approximately 110 mmWC. The supply of second charge of hot water 302 may increase the water temperature by about 1-3° C., so that the water temperature may then range between 41 and 44° C. While the second charge 302 of hot water is supplied, the laundry may be tumbled for a second tumbling step 332 for further sanitization. For example, the laundry may be tumbled for about 25-35 minutes in the drum 16 rotating at or below 100 rpm.

When the second tumbling step 332 is complete, the wash liquid in the treating chamber 18 may be drained from the washing machine 10 by the pump 74 to the drain conduit 76. At the same time, the drum 16 may be accelerated to high speed for extracting wash liquid from the laundry to the exterior of the washing machine 10. The drum 16 may typically be accelerated to 700-800 rpm at a high speed tumbling step 350, where the excess wash liquid may be extracted for about 2 minutes before being decelerated to below 100 rpm.

When the third tumbling step 350 is complete, the addition of cold water may take place in multiple steps for rinsing the laundry. As illustrated in FIG. 3A, cold water may be added in two steps 340, 342. It may also be understood that, depending on the treating cycle of operation, cold water may be added in any number of steps. For example, cold water may be added only in one step, while cold water may be added in three or more stepped increments in another embodiment.

For a first charge of cold water, approximately 17-23 liters of cold water 340 may typically be added to the treating chamber 18. With the addition of cold water 340, the sump temperature 324 may steeply drop down to about 23° C. in FIG. 3C. While the first charge of cold water 340 is added, the laundry may be tumbled in the drum 16 rotating at low spin speed, such as at or below 100 rpm, for about 8-10 minutes. Subsequently, the first charge of cold water 340 may be drained from the washing machine 10 by the pump 74 to the drain conduit 76, while the drum 10 is accelerated above 700 rpm during a high speed tumbling step 352 for extracting the wash liquid from laundry for about 2 minutes to the exterior of the washing machine 10.

A second charge of cold water 342 may be supplied to the treating chamber 18 after the drum 16 is decelerated in the fourth tumbling step 352. Approximately 17-23 liters of cold water 342 may be provided to the treating chamber 18 while the drum 16 rotates at or below 100 rpm for about 8-10 minutes, before the cold water 342 is drained to the drain conduit 76 and the drum 16 is again accelerated in a high speed tumbling step 354 approximately up to 700 rpm for dehydration of laundry articles. The drum 16 with laundry articles may also be accelerated in a high speed tumbling step 356 above 1000 rpm, for completing the rinsing step and sanitization cycle. The addition of the second charge of cold water 342 may drop the sump temperature 326 further down to about 20° C., as illustrated in FIG. 3C.

The sanitization cycle described in detail in FIGS. 3A, 3B, 3C and 3D was found to be highly effective in sanitizing the laundry by substantially removing known bacteria from the laundry without applying heat energy from the sump heater 84 or the steam generator 82. In a lab test conducted for testing the performance of the sanitization cycle in the present invention, it was confirmed that more than 99.9% of Pseudomonas aeruginosa, a bacterium causing inflammation and sepsis, was eliminated from a laundry sample after passing through the sanitization cycle described in the present invention. It was also observed that more than 99.9% of Staphylococcus aureus and Klebsiella pneumoniae were eliminated from a laundry sample after the sanitization cycle in the present invention.

Referring now to FIG. 4, a flow chart of a method 400 for conducting the sanitizing cycle for laundry in the laundry treating appliance without using the sump heater or steam generator is illustrated. The sequence of steps depicted for this method and the proceeding methods are for illustrative purposes only, and is not meant to limit any of the 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. It may be understood that the method may be incorporated into a cycle of operation for the laundry treating appliance, such as prior to or as part of any phase of treating cycle of operation. The method may also be a stand-alone cycle.

The method 400 starts with assuming that the user has placed laundry articles for sanitization within the treating chamber 18 and selected a cycle of operation for sanitization through the user interface 98. At 402, the first charge of hot water at a predetermined temperature may be added to a first predetermined level of the treating chamber 18. The amount of water may range between 18 and 22 liters. Alternatively, the amount of water may be supplied until the water level achieves a pressure of approximately 60 mmWC. The hot water temperature may range between 42 and 45° C.

At 404, the mixture of stain removing agent and detergent may be provided to the hot water in the treating chamber 18, followed by further tumbling of drum 16 at low speed for about 25-35 minutes uniformly dissolving the mixture in the hot water, as well as sanitizing laundry articles. Liquid type detergent may be mixed with water to be supplied from the dispenser 62 to the treating chamber 18. Solid or powder type stain removing agent may be loaded with laundry prior to onset of the sanitization cycle, while may be supplied from the dispenser 62. While the mixture of stain removing agent and detergent may be supplied to the treating chamber 18 after first charge of hot water is added to the treating chamber 18, it is also possible that the stain removing agent, detergent, laundry articles and first charge of hot water may be supplied to the treating chamber 18 substantially at the same time.

During the low speed tumbling, hot water and the treating chamber 18 exchanges heat energy with each other, and hot water may cool down. For compensating the heat energy loss, at 406, the second charge of hot water may be added to the first charge of hot water such that the water temperature may range between 41 and 44° C. About 6 liters of hot water may be supplied as the second charge of hot water. Alternately, the hot water may be added until the water level achieves a pressure of approximately 110 mmWC. The laundry articles in the treating chamber 18 may be further tumbled for another 25-35 minutes at low speed for further sanitization of laundry articles. Subsequently, the hot water may be drained from the treating chamber 18, and the drum 16 may subject to a high speed tumbling step 350 above 700 rpm to promote excess water extraction from the laundry articles.

When the drum 16 decelerates from high speed rotation, at 408, the pump 74 stops to drain the hot water. Approximately 17-23 liters of the first charge of cold water may be subsequently added to the treating chamber 18 for rinsing the laundry articles. The drum 16 may continue to rotate at low speed for about 10 minutes, before the first charge of cold water is drained from the washing machine 10 and the drum 16 rotates at high speed for dehydrating laundry articles at 352.

When the drum 16 decelerates from a high speed tumbling, the second charge of 17-23 liters of cold water 342 may be added to the treating chamber 18 at 410. The laundry may be tumbled in the drum 16 rotating at low speed for about 10 minutes. Subsequently, the second charge of cold water may be drained by turning on the pump 74, and the drum 16 may accelerated to a high speed for extracting excess water in the laundry at 354. The drum 16 may be subject to additional high speed tumbling step 356 before the sanitization cycle is complete. In another embodiment, two high speed drum tumbling steps 354, 356 may be combined into one high speed drum tumbling step. During the final high speed drum tumbling step 356, a predetermined amount of cold water may be supplied to the treating chamber 18 for completing the rinsing of laundry articles.

The invention described herein provides a method for conducting the sanitization cycle for laundry without using a heater or steam generator in the laundry treating appliance. The method may advantageously be used when the user may need to sanitize laundry without using the heater or steam generator in the laundry treating appliance, in a reduced time period. The possibility of substantially eliminating almost all of bacteria from the laundry may be maximized by employing the sanitization cycle comprising two, time-spaced hot water supplies, supply of the mixture of stain remover and detergent, and supply of two or more cold water in stepped increments combined with multiple times of intermittent high speed drum rotations.

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. For example, while the invention is described for a horizontal axis washing machine, the invention may also be implemented for a vertical axis washing machine. The drum rotation for the horizontal axis washing machine may be replaced with the agitation by means of the laundry agitator for the vertical axis washing machine in uniformly distributing the mixture in the water and/or sanitizing laundry. It will be understood that the values described herein are exemplary only and may vary by model or genus of washing machine. Water amounts, durations, water levels, temperatures, speed, may be different than described. Water consumption may also vary and the described water amounts may be determined by or controlled by the time a valve or valves may be on, by a predetermined water level reached or by a predetermined temperature target reached. Further, water amounts may be determined by or controlled by a predetermined detergent concentration reached or by a predetermined turbidity level reached.

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.

Claims

1. A method of substantially removing bacteria from laundry in a laundry treating chamber of a washing machine without using a heating element, comprising:

adding a first hot water charge to a first predetermined level in the laundry treating chamber at a first predetermined temperature;

dispensing a mixture of stain removing agent and detergent to the water in the laundry treating chamber;

tumbling the laundry in the hot water for a first predetermined time;

adding a second hot water charge to a second predetermined level in the laundry treating chamber;

tumbling the laundry in the hot water for a second predetermined time;

adding a first cold water charge to a third predetermined level in the laundry treating chamber, tumbling the laundry for a third predetermined time; and

adding a second cold water charge to a fourth predetermined level in the laundry treating chamber, tumbling the laundry for a fourth predetermined time.

2. The method of claim 1 wherein the first predetermined level ranges from 18 to 22 liters.

3. The method of claim 1 wherein the first predetermined level is about 60 mm Water Column for laundry size of 4.53 Kg.

4. The method of claim 1 wherein the first predetermined temperature ranges between 42° C. and 45° C.

5. The method of claim 1 wherein the first predetermined time ranges from 25 to 35 minutes.

6. The method of claim 1 wherein the second predetermined level is about 6 liters more than the first predetermined level.

7. The method of claim 1 wherein the second predetermined level is about 110 mm Water Column.

8. The method of claim 1 wherein the second predetermined time ranges from 25 to 35 minutes.

9. The method of claim 1 further comprising adding a third cold water charge to a fifth predetermined level, and tumbling the laundry for a fifth predetermined time.

10. The method of claim 9 wherein each cold water charge ranges from 17 to 23 liters.

11. The method of claim 1 wherein the third predetermined time is about 8 to 10 minutes.

12. The method of claim 1 wherein the mixture includes about 1.3 parts stain removing agent by weight and about 1.0 part detergent by volume.

13. The method of claim 1 wherein the weight of stain removing agent is about 1.3-1.5% of the weight of the laundry.