Patent Publication Number: US-6666220-B2

Title: Cookware washer

Description:
BACKGROUND OF INVENTION 
     This invention relates generally to domestic warewashing machines and systems, and more particularly to a domestic warewasher system adapted for washing cookware. 
     Known domestic dishwasher systems for residential use include a cabinet, a tub within the cabinet that defines an open sided wash chamber, and a door assembly that seals the open side of the wash chamber when the dishwasher is in use. The door assembly is attached to the dishwasher at a bottom end of the door and pivots about a hinge between fully open and fully closed positions, and dishes, glasses, utensils, food and beverage containers, etc., are loaded onto and from roller-equipped racks before and after operation of the dishwasher. The wash chamber includes a sump portion where washing fluid is pumped from a fluid circulation assembly through spray arm conduits to wash items loaded onto dishwasher racks in the wash chamber, and also where wash fluid is collected after being circulated throughout the wash chamber. 
     Conventionally, and despite the presence of a dishwasher, certain items are washed by hand instead of in the dishwasher. For example, some items, including larger cookware items such as pots and pans, lids, casserole dishes serving platters, and large cooking utensils are too large to fit in the dishwasher or of a shape that cannot be adequately accommodated by the dishwasher racks. In addition, while some dishwasher systems have specially designed cycles for pots and pans, the aforementioned difficulties in loading pots and pans into dishwasher racks often negates their use, and furthermore, experience has shown that baked-on adhered soils and residue typically remain after completion of such cycles. Still further, some manufacturers recommend against the use of certain cookware with dishwasher systems due to chemical resistance issues with detergents used in dishwasher systems. For at least these reasons, the belief that optimum washing and drying of cookware in conventional systems cannot be realized has taken root, and most residential users therefore hand wash and hand dry cookware and utensils with baked-on adhered soils, while the dishwasher is reserved for washing dishes, flatware, and eating utensils with non-baked on soils. 
     While specialized utensil holders have been developed to accommodate odd-shaped utensils, such as spatulas, serving spoons, ladles, tongs, long knives, etc., see, for example, U.S. Pat. No. 5,462,348, it has been generally found that conventional dishwasher cycles do not adequately clean such items, especially when they contain baked-on adhered soil and residue. Further, commercial pot and pan washing machines are available for use in the food service industry. See, for example, U.S. Pat. Nos. 5,131,419, 4,773,436, and 4,653,520. The large size and high cost of these units, however, render them generally impractical and unjustifiable for home use. 
     SUMMARY OF INVENTION 
     In one aspect, a cookware washer is provided. The cookware washer comprises a wash chamber, and a lower rack positioned within said wash chamber. The lower rack comprises a substantially unobstructed bottom surface. 
     In another aspect, a cookware washer is provided that comprises a wash chamber and a lower rack slidably coupled to said wash chamber. The lower rack comprises a substantially flat and unobstructed bottom surface adapted for retaining cookware. The cookware washer also comprises a fluid circulation assembly comprising a lower spray arm assembly proximate said lower rack, and a controller operatively coupled to said fluid circulation assembly. The controller is configured to operate said fluid circulation assembly for an extended time period and at elevated temperatures to clean soiled cookware items. 
     In still another aspect, a cookware washer for washing cookware items having baked-on food residue is provided. The cookware washer comprises a tub comprising a wash chamber, an upper rack coupled to said wash chamber and comprising a substantially flat bottom surface adapted for retaining cookware items, a lower rack coupled to said wash chamber and comprising a substantially flat bottom surface adapted for retaining cookware items, a fluid circulation assembly in flow communication with said wash chamber, and a controller operatively coupled to said fluid circulation assembly. Each of said upper and lower rack is horizontally positionable within said wash chamber, and the controller is configured to operate said fluid circulation assembly for an extended time period and at elevated temperatures to remove baked-on residue. 
     In yet another aspect, a residential cookware washer for washing cookware items having baked-on food residue is provided. The cookware washer comprises a tub comprising a wash chamber and at least one heavy duty rack coupled to said tub and adapted for horizontal movement between an extended position and a retracted position relative to said wash chamber. The at least one rack comprises a substantially flat bottom surface adapted for retaining cookware items, and said at least one rack is located in said wash chamber to provide a vertical clearance of at least 14 inches for cookware items. A door assembly is pivotally mounted to said tub and selectively positionable about a horizontal axis between an open position providing access to said wash chamber and a closed position closing said wash chamber. A fluid circulation assembly is in flow communication with said wash chamber and a controller is operatively coupled to said fluid circulation assembly and is configured to operate said fluid circulation assembly for an extended time period and at elevated temperatures to remove baked-on residue from cookware located in said at least one rack. 
    
    
     BRIEF DESCRIPTION OF DRAWINGS 
     FIG. 1 is a side elevational view of an exemplary cookware washer system. 
     FIG. 2 is a front perspective view of the cookware washer shown in FIG.  1 . 
     FIG. 3 is a perspective view of a lower rack for the cookware washer system shown in FIGS. 1 and 2. 
     FIG. 4 is a perspective view of an upper rack for the cookware washer system shown in FIGS. 1 and 2. 
     FIG. 5 is a schematic block diagram of the cookware washer system shown in FIGS.  1  and  2 . 
    
    
     DETAILED DESCRIPTION 
     FIG. 1 is a side elevational view of an exemplary cookware washer system  100  suitable for domestic, or residential, use. As used herein cookware shall refer generally to cooking utensils and items used predominately for food preparation, and therefore likely to encounter hard-to-clean baked-on residue and caked foodstuffs in use, as opposed to relatively lightly soiled flatware used predominately for food serving (e.g., serving plates, silverware, glassware and food storage containers) which is manageable by conventional dishwasher systems. For example, and unlike conventional dishwasher systems, cookware washer  100  is especially suited for pots and pans, lids for pots and pans, casserole dishes, serving platters, cookie sheets, mixing bowls, baking dishes, rotisserie pans, cutting boards, colanders cake pans, broiler inserts, graters, measuring cups, and large cooking utensils such as spatulas, serving spoons, ladles, tongs, and long knives that are generally incompatible with conventional dishwashers. Thus, cookware washer  100  is intended primarily for cookware items that conventionally are not washed in conventional dishwashers due to size constraints and baked-on adhered residue that is beyond the cleaning capability of conventional dishwashers. It is contemplated, however, that cookware washer  100  may be employed to wash heavily soiled flatware in addition to cookware. 
     Cookware washer  100  includes a cabinet  102  having a tub  104  therein and forming a wash chamber  106 . Tub  104  includes a front opening (not shown in FIG. 1) and a door assembly  120  hinged at its bottom  122  for movement about a horizontal axis between a normally closed vertical position (shown in FIG. 1) wherein wash chamber  106  is sealed shut for washing operation, and a horizontal open position (shown in FIG. 2) for loading and unloading of cookware from wash chamber  106 . Upper and lower guide rails  124 ,  126  are mounted on side walls of tub  104  and accommodate a lower cookware rack  130  and an upper cookware rack  132  respectively. 
     In one embodiment, each of racks  130 ,  132  is fabricated from steel and coated with a durable nylon material into a into a heavy duty lattice structure. The lattice structure is stronger and fabricated from a greater diameter wire material than conventional dishwasher racks. Lower rack  132  is taller than conventional dishwasher racks and therefore suited, as further described below, for accommodating larger cookware such as pots and pans. Upper rack  132 , as also described below is adapted to accommodate smaller cookware and cooking items. Each rack  130 ,  132  is adapted for horizontal movement on rollers  134  between an extended loading position (not shown) in which the rack is substantially positioned outside wash chamber  106 , and a retracted position (shown in FIG. 1) in which the rack is located inside wash chamber  106 . Additional rollers  134  are employed on each side of rack  130 ,  132  due to increased weight of cookware items relative to flatware items used with conventional dishwasher systems. A cookware utensil basket (not shown in FIG. 1) is removably attached to lower rack  132  for placement of cookware utensils. 
     A control panel (not shown in FIG. 1) is integrated into an escutcheon  136  that is mounted to door assembly  120 , or in further and/or alternative embodiments control selectors, (e.g., buttons, switches or knobs) or control displays, etc. may be mounted at a convenient location on an outer face  138  of door assembly  120 . The control panel and associated selectors and displays are coupled to control circuitry (not shown) and control mechanisms (not shown in FIG. 1) for operating a fluid circulation assembly (not shown in FIG. 1) that circulates water and wash fluid in cookware washer tub  104 . The fluid circulation assembly is located in a machinery compartment  140  located below a bottom sump portion  142  of tub  104 . 
     A lower spray-arm-assembly  144  is rotatably mounted within a lower region  146  of wash chamber  106  and above tub sump portion  142  so as to rotate in relatively close proximity to lower rack  130 . A mid-level spray-arm assembly  148  is located in an upper region of wash chamber  106  and is located in close proximity to upper rack  132  and at a sufficient height above lower rack  130  to accommodate a largest cookware item that is expected to be placed in lower rack  130  and washed in cookware washer  100 . In one embodiment, lower rack  130  and mid-level spray arm assembly are positioned relative to one another such that a vertical clearance C L  of approximately 15 inches is created between a bottom of lower rack  130  and mid-level spray-arm assembly  148 . As such, lower rack  130  may accommodate items of a larger size than conventional flatware such as, for example, a 14 inch circular cutting board or a 10 inch by 14 inch cookie sheet. 
     In a further embodiment, an upper spray arm assembly (not shown) is located above upper rack  130  at a sufficient height to accommodate cookware items. Upper rack  132  is positioned with respect the upper spray-arm assembly such that a second vertical clearance C U  is created to accommodate a largest cookware item expected to be washed in upper rack  132 . For example, in an illustrative embodiment, clearance C U  is sufficient to accommodate a 3 quart mixing bowl. 
     It is noted that in one embodiment, clearances C U  and C L  are accommodated in a tub  104  that is sized approximately equal to conventional dishwasher systems. As such, cookware washer  100  may be installed under-the-counter in a residential kitchen in a similar fashion to known dishwashers. It is contemplated, however, that dimensions of tub  104  may be varied to produce washers of varied capacities. 
     Lower and mid-level spray-arm assemblies  144 ,  148  and the upper spray arm assembly are fed by the fluid circulation assembly, and each spray-arm assembly includes an arrangement of discharge ports or orifices for directing washing liquid onto dishes located in upper and lower racks  132 ,  130 , respectively. The arrangement of the discharge ports in at least lower spray-arm assembly  144  provides a rotational force by virtue of washing fluid flowing through the discharge ports. The resultant rotation of lower spray-arm assembly  144  provides coverage of cookware with a washing spray. In various alternative embodiments, mid-level spray arm  148  and/or the upper spray arm are also rotatably mounted and configured to generate a swirling spray pattern above and below upper rack  132  when the fluid circulation assembly is activated and door assembly  120  is properly closed to seal wash chamber  106  for operation. 
     FIG. 2 is a front perspective view of cookware washer  100  with upper and lower spray arm assemblies  144 ,  148  (shown in FIG. 1) removed. Door assembly  120  is pivoted about a horizontal axis  150  extending through the door assembly hinge to an open position wherein racks  130 ,  132  may be loaded and unloaded. Racks  130 ,  132  are sized and dimensioned to substantially fill wash chamber  106  when racks  130 ,  132  are fully loaded with cookware items. Lower rack  130  is taller than upper rack  132  to accommodate taller items within rack  130 . Both racks  130 ,  132  are generally open and free from obstructions common to known dishwasher racks that may hinder or prevent placement of cookware therein. Lower rack  130  includes a utensil basket  152  for convenient loading and unloading of cooking utensils 
     Racks  130 ,  132  and clearances C U  and C L  permit loading of cookware item combinations that are not possible in conventional dishwashers. For example, in one illustrative embodiment, lower rack  130  has been found capable of holding a ceramic cooking tray, a 14 inch circular cooking board, a rotisserie pan, a 10 inch frying pan, a 7 quart pasta tray, two graters, and a 24 oz. glass baking dish, while upper rack  132  has been found to simultaneously contain a 1.5 quart mixing bowl, a 3 quart mixing bowl, a 10 inch frying pan, and a 2.5 liter backing dish. Thus, all these cookware items can be washed at once in cookware washer  100 . 
     In another illustrative example, the following items may be contained in racks  130 ,  132  and may be simultaneously washed in cookware washer  100 . A 3 quart mixing bowl, a 1.5 quart mixing bowl, a 9 inch round cake pan, and a 10 inch square cake pan may be loaded in upper rack  132 , while lower rack  130  contains a 14 inch by 17.5 inch cookie sheet, a 10 inch by 14 inch cookie sheet, an 8 inch square cake pan, a 4 quart double broiler insert, a 5 quart colander, an 8 inch ceramic baking dish, a 10 inch ceramic baking dish, a measuring cup, and a variety of cookware utensils in utensil basket  150 . 
     In yet another illustrative example to illustrate the versatility of cookware washer  100 , the following items may be washed together in cookware washer  100 . Two 10 inch frying pans, a 1.5 quart mixing bowl, and a 3 quart mixing bowl may be loaded in upper rack  132 , while a rotisserie pan, a 7 quart mixing bowl, a 14 inch frying pan, a 4 quart sauce pan, and a 12 quart stock pot may be loaded into lower rack  130 . 
     It is therefore evident that many other combinations of cookware items may be employed in cookware washer  100  that may not be contained in a conventional dishwasher system. When used in conjunction with a conventional dishwasher in the home, cookware washer  100  facilitates washing of cookware for a complete meal and the dishwasher facilitates washing of flatware for serving the meal with virtually no washing of items by hand. Thus, time consuming kitchen clean-up and cookware washing is substantially reduced and valuable time may be reserved for other more desirable pursuits. 
     FIG. 3 is a perspective view of lower rack  130  for the cookware washer  100  (shown in FIGS.  1  and  2 ). Lower rack  130  includes opposite front and back sides  160 ,  162 , lateral sides  164 ,  166  extending between respective edges of front and rear sides  160 ,  162 , and a substantially flat and unobstructed bottom  168  extending between lower edges of respective front and back sides  160 ,  162  and lateral sides  164 ,  166 . Each of rack sides  160 ,  162 ,  164 ,  166  and rack bottom  168  are formed by a plurality of heavy duty wire members, and rack lateral sides  164 ,  166  are extended to accommodate large cookware items, such as frying pan  170  without the items contacting side walls of cookware washer tub  104  (shown in FIG.  1 ). 
     Rack bottom  168  includes a plurality of cookware retainers  172  in which the wire members are upwardly extended in a curved configuration to facilitate placement of cookware items  170  in an upright position. Retainers  172 , in one embodiment, are integrally formed into continuously extending wire members in rack bottom  168  between rack front and back sides  160 ,  162 . Thus, additional frying pans, cookie sheets, baking plates, etc. may be contained side-by-side in an upright position between retainers  172  and rack lateral sides  164 ,  166 . In a further embodiment, retainers  172  are relatively low profile or, in other words, extend above rack bottom  162  a sufficient amount to retain cookware items without compromising an ability to place other cookware, such a stock pot (not shown) over retainers  172 . Due to the flat unobstructed bottom  168  of rack  130  and to the positions of retainers  172 , a wide variety of cookware items can be placed in lower rack  130 . 
     While the illustrated embodiment includes eight retainers  172 , it is appreciated that more or less retainers  172  may be employed in alternative embodiments within the scope of the present invention. Additionally, it is contemplated that other retainers could be employed in alternative embodiments in lieu of retainers  172 . For example, retainers similar to conventional upstanding tines commonly used in dishwasher racks may be employed, albeit with appropriate modification for employment with heavy duty lower rack  130 . 
     FIG. 4 is a perspective view of upper rack for  132  for cookware washer  100  (shown in FIGS.  1  and  2 ). Upper rack  132  includes opposite front and back sides  180 ,  182 , lateral sides  184 ,  186  extending between respective edges of front and rear sides  180 ,  182 , and a substantially flat and unobstructed bottom  188  extending between lower edges of respective front and back sides  180 ,  182 , and lateral sides  184 ,  186 . Each of rack sides  180 ,  182 ,  184 ,  186  and rack bottom  188  are formed by a plurality of heavy duty wire members, and rack lateral sides  184 ,  186  are extended to accommodate cookware items, such as sauce pan  190  and casserole dish  192  without the items contacting side walls of cookware washer tub  104  (shown in FIG.  1 ). 
     In one embodiment rack bottom  188  includes a plurality of fold down tines  196  (shown in phantom in FIG.  4 ). Tines  196  are selectively positionable between a folded position substantially flush with rack bottom  188 , and an upright position (not shown) wherein tines  196  extend substantially vertically from rack bottom  188 . When in the upright position, a plurality of cookware items, such as lids for pots and pans, may be arranged side-by-side between the tines and in an upright position. When tines  196  are folded down, cookware items may be placed face down on rack bottom  88 , as illustrated with pan  190  and casserole dish  192 . A raised handle portion  196  extends upwardly from rack front side  180 . 
     In an alternative embodiment, rack  132  includes retainers similar to retainers  172  (shown in FIG. 3) in lieu of tines  196 . 
     Aside from rack  130  (shown in FIG. 3) and rack  132  (shown in FIG. 4) that are each configured to accept a multitude of cookware items in an efficient and organized fashion, cookware washer  100  (shown in FIGS. 1 and 2) also includes a control system, unlike conventional dishwashers, that is adapted especially for adequately washing and drying and cookware placed in cookware wash chamber  106  (shown in FIG.  1 ). 
     FIG. 5 is a schematic block diagram of a cookware washer control system  200  for use with cookware washer  100  (shown in FIGS.  1  and  2 ). Control system  200  includes a controller  202  which may, for example, be a microcomputer  204  coupled to a user interface input  206 . An operator may enter instructions or select desired cookware washer cycles and features via user interface input  206 , and a display  208  coupled to microcomputer  204  displays appropriate messages, indicators, a timer, and other known items of interest to cookware washer users. A memory  210  is also coupled to microcomputer  204  and stores instructions, calibration constants, and other information as required to satisfactorily complete a selected wash cycle. Memory  210  may, for example, be a random access memory (RAM). In alternative embodiments, other forms of memory could be used in conjunction with RAM memory, including but not limited to electronically erasable programmable read only memory (EEPROM). 
     Power to system  200  is supplied to controller  202  by a power supply  212  configured to be coupled to a power line L. Analog to digital and digital to analog converters (not shown) are coupled to controller  202  to implement controller inputs and executable instructions to generate controller output to a fluid circulation assembly  214  according to known methods. Fluid circulation assembly  214  includes a water pump, water heater, water filters, etc. to deliver washing fluids and rinses to spray-arm assemblies  144 ,  148  (shown in FIG.  1 ). In response to manipulation of user interface input  206 , controller  202  monitors various operational factors of cookware washer  100 , and executes operator selected functions and features according to known methods. Of course, controller  202  may be used to control system elements and execute functions beyond that specifically described herein. 
     Controller  202  operates the various components of fluid circulation assembly  214  in a designated wash cycle familiar to those in the art of dishwashers. 
     However, and unlike known dishwasher systems, controller  202  executes extended wash cycles adequate to remove baked-on adhered food product and residue from cookware. More specifically, controller memory  210  includes a plurality of lookup tables  216  including constants and function parameters for operation of fluid circulation assembly  214  in response to a selected wash cycle via manipulation of user interface input  206 . However, each of the lookup tables  216  includes data pertaining to cookware wash cycles, i.e., wash cycles specifically created to address baked-on adhered residues common to cookware. 
     For example, washing efficacy of cookware in cookware washer  100  is largely attributable to three parameters, wash cycle time (in part a function of the number of water fills of the sump portion for circulation in wash chamber  106  by fluid circulation assembly  214 ), a water temperature of the water fills, and the detergent composition used in cookware washer  100 . It has been found that with appropriate adjustment of the cycle time and the water temperature, cookware may be adequately washed with conventional dishwasher detergents. 
     For example, an approximate comparison of a typical dishwasher operation and a cookware washer cycle for cookware washer  100  (shown in FIGS. 1 and 2) appears in the tables below for a variety of washer settings. 
     
       
         
           
               
               
               
               
             
               
                 TABLE 1 
               
               
                   
               
               
                   
                 DISHWASHER 
                 WATER TEMP 
                 CYCLE TIME 
               
               
                 CYCLE 
                 FILLS 
                 (° F.) 
                 (minutes) 
               
               
                   
               
             
            
               
                 Heavy, Sanitation 
                 6 
                 160 
                 76 
               
               
                 Temperature 
               
               
                 Normal, High 
                 5 
                 135 
                 67 
               
               
                 Temperature 
               
               
                 Light, Normal 
                 4 
                 125 
                 26 
               
               
                 Temperature 
               
               
                   
               
            
           
         
       
     
     
       
         
           
               
               
               
               
             
               
                 TABLE 2 
               
               
                   
               
               
                   
                 COOKWARE 
                 WATER TEMP 
                 CYCLE TIME 
               
               
                 CYCLE 
                 FILLS 
                 (° F.) 
                 (minutes) 
               
               
                   
               
             
            
               
                   
               
            
           
           
               
               
               
               
            
               
                 Heavy, Sanitation 
                 7 
                 171 
                 107 
               
               
                 Temperature 
               
               
                 Normal, High 
                 5 
                 145 
                 89 
               
               
                 Temperature 
               
               
                 Light, Normal 
                 4 
                 135 
                 37 
               
               
                 Temperature 
               
               
                   
               
            
           
         
       
     
     Therefore, with increased cycle time and increased temperatures, cookware may be effectively washed in cookware washer  100 . Of course, other acceptable cookware cycles may be empirically or theoretically determined. 
     Control parameters to drive the cycle length, water fills, and water temperature to acceptable levels for washing cookware, such as those set forth above, are believed to be within the purview of those in the art and beyond the scope of the present invention. It is further believed that one of ordinary skill in the art would be able to construct and program such a cookware washer controller without further explanation. 
     A convenient domestic cookware washer system is therefore provided in a compact and comparatively cost effective package in relation to known commercial pot and pan washing machines. Cookware washer  100  may be inconspicuously mounted under a countertop in a residential kitchen and in one embodiment occupies approximately the same space as a conventional dishwasher. Time intensive hand washing of cookware items is substantially avoided by virtue of cookware washer  100 , thereby increasing convenience in residential kitchens and allowing more time for entertainment of guests and pursuit of worthier interests. 
     While the invention has been described in terms of various specific embodiments, those skilled in the art will recognize that the invention can be practiced with modification within the spirit and scope of the claims.