Abstract:
An appliance having an enclosure arranged to receive articles to be treated also includes a water container and a steam chamber with a steam outlet. A water dispenser is arranged to dispense water from the water container to the steam chamber. A heating element is thermally associated with the steam chamber. A control is arranged to selectively operate the heating element. A steam path extends between the steam outlet and the enclosure. A chemical dispenser is positioned along the steam path. The heating element heats water in the steam chamber to create steam, and the chemical dispenser adds a chemical to the steam as the steam passes through the steam path.

Description:
BACKGROUND OF THE INVENTION 
       [0001]    The present invention relates to a method and apparatus for providing a bio prevention cycle for an automatic clothes washer, and more particularly to methods and systems for preventing the build-up of microorganisms or other materials in an automatic clothes washer or similar appliances. 
         [0002]    Under normal usage of an automatic clothes washer, detergent residues build up with minerals and soils, which harden on the washer, often in areas that the consumer cannot see. This is particularly true when a consumer uses a higher sudsing detergent. These soils then form an excellent medium for supporting and growing bacteria, fungi, and other microorganisms. Consumers rarely see such microorganisms, but the washer will eventually release or have a foul odor due to these microorganisms. 
         [0003]    It would therefore be an improvement in the art if there was provided a method or system for killing the microorganisms which are existing in an automatic clothes washer. 
       SUMMARY OF THE INVENTION 
       [0004]    The present invention provides an improvement in the art by providing methods and systems for an automatic washer which will kill microorganisms that are present in the washer. 
         [0005]    In an embodiment of the invention, an appliance having an enclosure arranged to receive articles to be treated also includes a water container and a steam chamber with a steam outlet. A water dispenser is arranged to dispense water from the water container to the steam chamber. A heating element is thermally associated with the steam chamber. A control is arranged to selectively operate the heating element. A steam path extends between the steam outlet and the enclosure. A chemical dispenser is positioned along the steam path. The heating element heats water in the steam chamber to create steam, and the chemical dispenser adds a chemical to the steam as the steam passes through the steam path. 
     
     
       BRIEF DESCRIPTION OF THE DRAWING 
         [0006]      FIG. 1  is a perspective view of an automatic washer embodying the principles of the present invention. 
           [0007]      FIG. 2  is a schematic partial view of the interior of one embodiment of the disinfecting unit of the automatic washer of  FIG. 1 , consistent with methods and systems embodying the principles of the present invention. 
           [0008]      FIG. 3  is a perspective view of one embodiment of the exterior of the disinfecting unit. 
           [0009]      FIG. 4  is a flow diagram of the steps performed by the disinfecting unit. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
       [0010]    The present invention is useful in many different types of appliances having a washing or cleaning cycle, such as clothes washers, dish washers, clothes refreshers, dry cleaning appliances, etc., in which various types of articles are to be treated. For the purposes of disclosing an embodiment of the invention, the environment of a clothes washer is used, although the invention is not limited to such an appliance, or to the particular type of clothes washer illustrated. 
         [0011]    In  FIG. 1  there is illustrated an appliance in the form of an automatic washer generally at  10  embodying the principles of the present invention. The washer has an outer cabinet  12  with an openable lid  13  which encloses an imperforate wash tub  14  for receiving a supply of wash liquid. Concentrically mounted within the wash tub is a wash basket  16  for receiving a load of materials to be washed and a vertical axis agitator  18 . A motor  20  is provided which is drivingly connected to the agitator  18  to rotatingly drive it in an oscillatory or rotary manner, and is also selectively connectable to the basket  16  for simultaneous rotation with the agitator  18 . The assembly of the tub  14 , wash basket  16 , agitator  18 , and motor  20  is mounted on a suspension system  22 . A plurality of controls  26  are provided on a control console  28  for automatically operating the washer through a series of washing, rinsing, and liquid extracting steps. 
         [0012]    The washer also includes a disinfecting unit  30 , which may be connected to an external water supply via a conduit  32  and to the wash tub  14 , or elsewhere in the enclosure formed by the outer cabinet  12 , via a conduit  34 . The location for the disinfecting unit  30  is only schematically illustrated, and it could actually be located in a variety of different locations in the cabinet  12 , where space permits, or even remote from the cabinet, such as in an adjacent cabinet or appliance. The invention can also be used with clothes washers that do not include a vertical agitator, such as those that agitate by other mechanisms, such as nutating plates, baffles on the basket, etc., as well as horizontal axis washers which provide agitation via tumbling. Other washing or cleaning appliances do not agitate the materials being washed or cleaned, but rather provide sprays or mists of water or other cleaning, washing, refreshing and rinsing fluids. 
         [0013]      FIG. 2  provides the details of the disinfecting unit  30 . The disinfecting unit  30  includes a water container  36 , a heating element  38 , a steam chamber  40 , a chemical or biocide container  42 , and a mixing chamber  44 . The mixing chamber  44  includes a projection which may be in the form of a wire  46  attached to a chemical dispenser  48 . The chemical dispenser  48  may be electrically or mechanically controlled, although a control is not necessary in all embodiments. The water container  36  may be automatically filled via the conduit  32  from an external water supply, such as that used to supply water to other parts of the washer  10 . 
         [0014]    In other embodiments, the water container  36  may include an openable cap  50  ( FIG. 3 ) and the user of the washer may refill the water container manually. The chemical container  42  may also include an openable cap  52  to permit refilling of the chemical. In some embodiments, the chemical container may contain a long term supply, such as a supply that should last for  10  years under normal usage. The chemical container  42  might be a cartridge that is removable and replaceable, with a fresh supply of chemical, separately from the remainder of the disinfecting unit  30 . In still other embodiments, the entire disinfecting unit  30  is removable and replaceable with a fresh unit, so that no refilling is necessary, or so that accessibility for refilling is improved. 
         [0015]    The water container  36  includes a water dispenser  54 , which also may be electrically or mechanically controlled, to cause drops of water to be dispensed into the steam chamber  40 , preferably located below the water container. The heating element  38  is thermally associated with a portion of the steam chamber  40  to heat the water drops that have entered the steam chamber. Although depicted as being at the bottom of the steam chamber  40 , one skilled in the art will recognize that the heating element  38  could be associated with the steam chamber in a number of configurations. For example, the heating element  38  could surround the steam chamber  40 , or it could be located in the center of the chamber. When the heating element  38  is located at the bottom of the steam chamber  40 , the water drops from the water container  36  will fall on a surface  56  heated by the heating element, and will quickly be converted to steam. 
         [0016]    A passageway  58  allows steam to flow along a path from the steam chamber  40  to the mixing chamber  44 . The chemical dispenser  48  allows chemical drops from within the chemical container  42  to flow along the wire  46  into the mixing chamber  44 . These drops will coat a large surface area of the wire  46 , allowing for quick and efficient absorption or adsorption of the chemical by the steam in the mixing chamber  44 . One skilled in the art will recognize that other configurations or arrangements to dispense the chemical into the mixing chamber  46  can be used. For example, the chemical could be a solid that dissolves upon contact with the steam, or the chemical could automatically travel down the wire without the dispenser, like a wick. 
         [0017]    A wide variety of chemicals may be used with the invention, including various pesticides, for example, common EPA registered antimicrobials, such as the full list of “MICROBAN” products. Also, hydrogen peroxide and its variations, silver, copper or zinc ions, chlorine bleach, and in some instances, simply steam. 
         [0018]    The steam chamber  40  may have a collection sump  60  for receiving any condensate from the steam that has not exited the steam chamber. The mixing chamber  44  may have a bottom wall or floor  62  which is sloped downwardly towards the passageway  58 , also to allow condensate, or excess chemical liquid, to flow into the collection sump  60  in the steam chamber  40 . If the disinfecting unit  30  is permanent or refillable, the sump may have an openable drain to allow removal of collected liquids from time to time. Alternatively, a liquid moving mechanism, such as a pump or piston, could be used to redirect the condensate back to the surface  58  heated by the heating element  38  to assure that all of the chemical and water is dispensed with the steam. 
         [0019]    In operation, when a disinfecting cycle is initiated, the water dispenser  54 , operated by a control  61 , permits drops of water to leave the water container  36  and fall into the steam chamber  40 . The heating element  38 , also operated by the control  61 , heats the water in the steam chamber  40  until steam is formed (step  63 ,  FIG. 4 ). The steam exits through the passageway  58  to enter mixing chamber  44 . The chemical dispenser  48  controllably allows chemical drops to enter the mixing chamber  44  via the wire  46 . The chemical drops are absorbed or adsorbed (depending on the solubility of the chemical in water) by the steam in the mixing chamber  46 , so that the steam becomes impregnated with the chemical (step  64 ). The impregnated steam enters the wash tub  14  through the conduit  34  (step  65 ). 
         [0020]    The heating element  38  continues to heat the water until the temperature in the wash tub  14  reaches a threshold temperature for a given duration (step  66 ). Temperature sensors  70  provided at appropriate locations within the appliance, which communicate with the control  61 , measure the temperature in the region of the wash tub. The threshold temperature may be 65° C., 70° C., 75° C. or higher for durations of 5 minutes, 10 minutes, 15 minutes, or longer to kill the microorganisms. Preferably, the temperature will be elevated to 67-70° C. for 10 minutes, as determined by a clock  74  in the control  61 . With increased temperatures, the duration may be shortened and with decreased temperatures, the duration may be increased. After the threshold temperature is reached for the given duration, the control  61  terminates operation of the heating element  38  to stop the heating of the water (step  76 ) and terminates the dispensing of water and chemical. For some chemicals, such as silver, copper or zinc ions, would allow for ambient temperatures to be used, rather than elevated temperatures for some given period of time. 
         [0021]    The steam impregnated with the chemical is used to thermally and/or chemically kill any microorganisms that exist in the appliance, or to provide other chemical treatment in the appliance, such as scale removal. The steam is able to transport the chemical to areas that are not typically reachable by other means, e.g., by rinsing the washer tub or basket with chemically treated water. In a washer environment, the present invention allows for treatment of the inside and outside of the basket, the tub, the sump, and all of the hoses. 
         [0022]    The bio prevention (or other chemical treatment) cycle can be performed as an automatic cycle by the control operating the washer  10 , such as at the end of each complete wash cycle. Alternatively, or in addition, the bio prevention cycle could be initiated by the user via a manual selection on a control panel of the washer. 
         [0023]    The use of the present invention could also provide for reduced water usage in a wash cycle. The water usage savings could come from the utilization of steam as the vehicle to deliver heat to the wash load, rather than a deep water fill. Less energy would be required to heat a smaller volume of water into steam for the heating, in addition to using less water in the wash cycle. 
         [0024]    As is apparent from the foregoing specification, the invention is susceptible of being embodied with various alterations and modifications which may differ particularly from those that have been described in the preceding specification and description. It should be understood that we wish to embody within the scope of the patent warranted hereon all such modifications as reasonably and properly come within the scope of our contribution to the art.