Abstract:
A multirack speedcook oven includes a cooking cavity, a plurality of racks within the cooking cavity, an RF generation module operationally coupled to the cooking cavity and configured to deliver microwave energy into the cooking cavity, at least one heat source positioned within the cavity and configured to supply heat energy to the cooking cavity, and a control configured to accept data regarding said plurality of racks, the control operationally coupled to the RF generation module, and the at least one heat source for selective control thereof based on the accepted data.

Description:
BACKGROUND OF THE INVENTION 
     This invention relates generally to ovens and, more particularly, to an oven operable in speedcooking, microwave, and convection/bake modes. 
     Ovens typically are either, for example, microwave, radiant, or thermal/convection cooking type ovens. For example, a microwave oven includes a magnetron for generating RF energy used to cook food in an oven cooking cavity. Although microwave ovens cook food more quickly than radiant or thermal/convection ovens, microwave ovens do not brown the food. Microwave ovens therefore typically are not used to cook as wide a variety of foods as radiant or thermal/convection ovens. 
     Radiant cooking ovens include an energy source such as lamps which generate light energy used to cook the food. Radiant ovens brown the food and generally can be used to cook a wider variety of foods than microwave ovens. Radiant ovens, however, cook many foods slower than microwave ovens. 
     In thermal/convection ovens, the food is cooked by the air in the cooking cavity, which is heated by a heat source. Standard thermal ovens do not have a fan to circulate the hot air in the cooking cavity. Convection ovens use the same heat source as a standard thermal oven, but add a fan to increase cooking efficiency by circulating the hot air around the food. Thermal/convection ovens cook the widest variety of foods. Such ovens, however, do not cook as fast as radiant or microwave ovens. 
     One way to achieve speedcooking in an oven is to include both microwave and radiant energy sources in a microwave assist mode. The combination of microwave and radiant energy sources facilitates fast cooking of foods. In addition, and as compared to microwave only cooking, a combination of microwave and radiant energy sources can cook a wider variety of foods. 
     Microwave assist ovens do not feature multirack cooking in their speedcook modes or do not recommend cooking multiple racks of food in the speedcook mode. With the addition of multiple racks in the oven, evenness of cooking becomes a greater issue. The relative position of food within the cooking cavity with respect to the air flow paths within the oven impacts the evenness of cooking. For example, if a portion of the food is directly in the flow path of air from the convection fan, such food portion may cook more quickly than another portion of the food that is not in the direct air flow path. Uneven cooking can cause variation in browning and a darkening around the edges in baked products. 
     BRIEF DESCRIPTION OF THE INVENTION 
     In one aspect, an oven includes a cooking cavity, a plurality of racks within the cooking cavity, an RF generation module operationally coupled to the cooking cavity and configured to deliver microwave energy into the cooking cavity, at least one heat source positioned within the cavity and configured to supply heat energy to the cooking cavity, and a control configured to accept data regarding said plurality of racks, the control operationally coupled to the RF generation module, and the at least one heat source for selective control thereof based on the accepted data. 
     In another aspect, a method for operating a multirack oven having a microcomputer, an RF generation module, a bake element, a broil element, and a convection element, includes, obtaining at least one input from a user indicative of whether the oven is to operate in a microwave mode, a convection mode, a bake mode, a broil mode, and a speedcooking mode, obtaining a further input from a user indicative of a number of racks, and energizing the RF generation module, the bake element, the broil element, and the convection element in accordance with the user input. 
     In yet another aspect, a method for operating a speedcook oven in a speedcook mode, includes, receiving an indication of a number of racks, operating the oven in a predetermined radiant cooking cycle based on the received indication of a number of racks, operating the oven in a predetermined microwave cooking cycle based on the received indication of a number of racks, operating the oven in a predetermined convection fan cycle based on the received indication of a number of racks, and wherein the operating steps are performed concurrently for a user specified cooking time. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is a front view of a speedcook wall oven. 
     FIG. 2 is a perspective view of the oven shown in FIG.  1 . 
     FIG. 3 is an exploded view of the oven shown in FIG.  1  and FIG.  2 . 
     FIG. 4 is an exploded view of control panel that can be used with the oven shown in FIG. 1, FIG. 2, and FIG.  3 . 
     FIG. 5 is a front view of a speedcook range. 
     FIG. 6 is a perspective view of the oven shown in FIG.  4 . 
     FIG. 7 is a schematic illustration of the oven shown in FIG.  4  and FIG.  5 . 
     FIG. 8 is a chart of a speedcook algorithm for use in multirack cooking. 
     FIG. 9 is a front view of another embodiment of an oven. 
     FIG. 10 is a schematic illustration of the oven shown in FIG.  9 . 
     FIG. 11 is a schematic illustration of the oven shown in FIG. 9 in multirack speedcooking mode. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In the exemplary embodiment, the methods and apparatus described herein are applicable to the operation of an oven that includes sources of radiant and microwave energy as well as a convection heating element and a bake heating element. Although three specific embodiments of such an oven are described herein, it should be understood that the present invention can be utilized in combination with many other such ovens and is not limited to practice with the ovens described herein. For example, one oven described herein below is a speedcook oven including a range. The present invention, however, is not limited to practice with just full-size ovens that include a rangetop, but can be used with many other types of ovens such as countertop or built-in wall ovens, over the range type ovens, and a double wall oven. 
     FIG. 1 is a front view of a speedcook oven  10 . FIG. 2 is a perspective view of speed cook oven  10 . FIG. 3 is an exploded view of the oven shown in FIG.  1  and FIG.  2 . In the exemplary embodiment, speedcook oven  10  includes an oven cavity  12 , a door  14  including a window  16  provided for viewing food in oven cooking cavity  12 , and a handle  18  secured to door  14 . Oven  10  also includes a control panel  20  that includes at least one display  22 , a plurality of tactile control buttons  24 , and various knobs or dials. 
     Speedcooking oven  10  includes a broil heating element  26 , a bake heating element  28 , a convection heating element  30 , a convection fan  32 , and a convection motor  34  mechanically coupled to convection fan  32  such that heat generated by convection element  30  is provided to oven cavity  12 . Speedcooking oven  10  also includes a magnetron  36  and a temperature sensor  38  configured to sense the temperature within cavity  12 . Broil heating element  26  is located at a top area inside speedcooking oven  10  and bake heating element  28  is located at a bottom area inside speedcooking oven  10 . Convection heating element  30  and convection fan  32  are located at a back area inside speedcooking oven  10 . A cover  40  can be provided to shield a user from convection heating element  30  and convection fan  32 . Magnetron  36  is located above broil heating element  26 . A plurality of removable oven racks  19  are positioned within oven cavity  12 . 
     Magnetron  36  generates microwave energy to speed cook various food items, which are supported by racks  19 . The microwaves are evenly distributed inside speedcooking oven  10  by a microwave dispersement plate (not shown in FIGS. 1-3) positioned between magnetron  36  and broil heating element  26 . The microwave dispersement plate is similar to the match plate described in U.S. Pat. No. 6,452,142. Door  14  of speedcooking oven  10  allows access to speedcooking oven  10 . Door  14  includes an interlock (not shown) configured to de-energize magnetron  36  when door  14  is opened while continuing cycling of the other heating elements. In use, broil heating element  26 , bake heating element  28 , convection heating element  30 , and convection fan  32  will continue to operate in accordance with the methods described herein for a first time to allow an operator to enter additional cooking time if desired or to check on the completeness of the food. At the completion of the first time, all heating elements still operating will be de-energized. 
     FIG. 4 is an exploded view of control panel  20  that includes a first display  42 , a second display  44 , and a control board  46 . In the exemplary embodiment, first display  42  is an alphanumeric menu display  42  that allows the user to choose between various functions that speedcooking oven  10  performs, and second display  44  is a status display  44  that notifies the user of various conditions inside speedcooking oven  10 . For example, status display  44  can notify the user that the temperature inside speedcooking oven is 327 degrees Fahrenheit. 
     Speedcooking oven  10  also include a microprocessor  48  positioned on a control board  46  and electrically coupled to alphanumeric display  42 . Microprocessor  48  is configured to operate various components of oven  10 , such as, but not limited to, broiler heating element  26 , bake heating element  28 , convection fan  32 , and magnetron  36 , and convection heating element  30 . In the exemplary embodiment, temperature sensor  38  is located at least partially within cavity  12  and microprocessor  48  is configured to receive an input from temperature sensor  38 . Microprocessor  48  is programmed to perform functions described herein, and as used herein, the term microprocessor is not limited to just those integrated circuits referred to in the art as microprocessors, but broadly refers to computers, processors, microcontrollers, microcomputers, programmable logic controllers, application specific integrated circuits, and other programmable logic circuits, and these terms are used interchangeably herein. 
     In use, cooking selections are made by depressing tactile control buttons  24  and when the desired selection is displayed, pressing a start button. For example, many cooking algorithms can be preprogrammed in the oven memory for man different types of foods. When a user is cooking a particular food item for which there is a preprogrammed cooking algorithm, the preprogrammed cooking algorithm is selected by operating the control buttons  24  until the selected food name is displayed and then pressing a start button. Instructions and selections are displayed on display  44 . 
     FIG. 5 is a front view of a speedcook oven  50  including a rangetop  51 . FIG. 6 is a perspective view of speed cook oven  50 . FIG. 7 is an exploded view of the oven shown in FIG.  5  and FIG.  6 . In the exemplary embodiment, speedcook oven  50  includes an oven cavity  52 , a door  54  including a window  56  provided for viewing food in oven cooking cavity  52 , and a handle  58  is secured to door  54 . Oven  50  also includes a control panel  60  that includes at least one display  62 , a plurality of tactile control buttons  64 , and various knobs or dials.: 
     Speedcooking oven  50  includes a broil heating element (not shown), a bake heating element  59 , a convection heating element (not shown), a convection fan (not shown), and a convection motor (not shown) mechanically coupled to the convection fan such that heat generated by the convection element is provided to oven cavity  52 . Speedcooking oven  50  also includes a magnetron (not shown) and a thermistor (not shown) configured to sense the temperature within cavity  52 . In the exemplary embodiment, the broil heating element is located at a top area inside speedcooking oven  50  and bake heating element  59  is located at a bottom area inside speedcooking oven  50 . The convection heating element and the convection fan are located at a back area inside speedcooking oven  50 . A cover (not shown) can be provided to shield a user from the convection heating element and the convection fan. The magnetron is located approximately above the broil heating element. 
     The magnetron generates microwave energy to speed cook various food items, which are supported by a rack (not shown). The microwaves are evenly distributed inside speedcooking oven  50  by a microwave disbursement plate (not shown) positioned between the magnetron and the broil heating element. Door  54  of speedcooking oven  50  allows access to speedcooking oven  50 . In the exemplary embodiment, speedcooking oven  50  also includes control panel  20  shown in FIG.  4 . 
     Some of the cooking functions of ovens  10  and  50  include the further option of cooking in single rack mode or multirack mode. In single rack mode, food is being cooked only on one oven rack. In multirack mode, food items are being cooked on more than one oven rack. Display  22  includes a multi light (not shown). When the user selects oven/bake a first time, multi light is illuminated indicating that oven  10  is in multirack mode as explained in detail below. When the user selects oven/bake a second time, multi light is not illuminated indicating that oven  10  is in single rack mode as explained below. 
     The user can toggle between single rack mode and multirack mode. In one embodiment, however, multirack mode is the only mode. In an alternative embodiment, and rather than relying on user input regarding selection of the number of racks on which food is located, at least one sensor senses whether one rack or multiple racks (e.g., by pressure or weight on a rack, or by sensing the presence of baking ware) are being used and provides an indication of rack mode to an oven controller automatically. Additionally, multirack mode need not be the first mode. For example, when the user selects oven/bake a first time, multi light is not illuminated indicating that oven  10  is in single rack mode, and when the user selects oven bake a second time, multi light is illuminated indicating that oven  10  is in multirack mode. 
     In multirack cooking, food is placed at multiple levels within oven  10 . Throughput of food through oven  10  is increased while maintaining evenness of cooking. Through the combination of speedcooking with multirack cooking, greater amounts of food are prepared quickly. Coordination and application of energy from bake element  28 , broil element  26 , convection element  30 , and microwave source  36 , is controlled by programmed algorithms in an oven controller. 
     Such algorithms generally combine radiant and microwave cooking modes with convection fan cycling and are used in speedcooking where the user has no specific recipe for the food being prepared. For instance, the algorithm includes a radiant phase where bake, and/or broil, and/or convection elements are operated with each element being turned on for a prescribed period of time. Also, there is a microwave phase, concurrently with the radiant phase, whereby the microwave source is cycled on and off. Additionally, a convection fan cycle includes reversal of fan direction of rotation concurrently with the radiant and microwave heating phases. 
     One such Algorithm  700 , shown in FIG. 8, has empirically provided successful results. Algorithm  700  includes a radiant phase  710 , a microwave phase  720 , and a fan cycling phase  730 . As applied to ovens  10  and  50 , in radiant phase  710 , convection element  30  is operated continuously with no off time. In microwave phase  720 , there is a 30 second cycle where magnetron  36  is energized for 7 seconds and then deenergized for 23 seconds, after which the cycle is repeated. Microwave phase  720  operates concurrently with radiant phase  710 . Convection fan cycling phase  730  also operates concurrently with radiant phase  710  and microwave heating phase  720 , wherein convection fan  32  is operated on an 80 second cycle including 30 seconds rotating in one direction, and then 30 seconds rotating in the opposite direction, with 10 seconds allotted for the fan to slow down before reversing directions. Algorithm  700  is invoked when the user selects speedcook and multirack cooking mode. 
     FIG. 9 is a front view of an over the range type oven  100  in accordance with one embodiment of the present invention. Oven  100  includes an outer case  102 , a plastic door frame  104 , and a control panel frame  106 . Oven  100  further includes a stainless steel door  108  mounted within door frame  104 , an injection molded grille  110 , and a bottom panel  112 . A window  114  in door  108  is provided for viewing food in the oven cooking cavity, and an injection molded plastic handle  116  is secured to door  108 . A control panel  118  is mounted within control panel frame  106 . 
     Control panel  118  includes a display  120 , an injection molded knob or dial  122 , and tactile control buttons  124 . Selections are made by rotating dial  122  clockwise or counterclockwise and when the desired selection is displayed, pressing dial  122 . Instructions and selections are displayed on vacuum fluorescent display  120 . A number of cooking modes are provided, including basic modes such as bake mode, broil mode, and microwave mode, in addition to a convection mode and a speedcook mode, all of which will be described in greater detail below. 
     FIG. 10 is a schematic illustration of oven  100  shown in FIG.  9 . As shown in FIG. 10, and in an exemplary embodiment , oven  100  includes a shell  126 , and a cooking cavity  128  is located within shell  126 . Cooking cavity  128  is constructed using high reflectivity (e.g., 72% reflectivity) stainless steel, and a turntable  130  is located in cavity  128  for locating food. Oven  100  includes a microwave module, for microwave cooking, among others, an upper heater module  132 , for use in broil mode, among others, and a lower heater module  134 , used in bake mode, among others. Microwave module includes a magnetron located on a side of cavity. Magnetron, in an exemplary embodiment, delivers a nominal 900 W into cavity according to standard IEC (International Electrotechnical Commission) procedure. Upper heater module  132  includes radiant heating elements illustratively embodied as a ceramic heater  136  and a halogen cooking lamp  138 . In the exemplary embodiment, ceramic heater  136  is rated at 600 W and halogen cooking lamp  138  is rated at 500 W. Upper heater module  132  also includes a sheath heater  140 . In the exemplary embodiment, sheath heater  140  is rated at 1100 W. A convection fan  142  is provided for blowing air over heating elements and into cooking cavity  128 . Lower heater module  134  includes at least one radiant heating element illustrated as a ceramic heater  144  rated at 375 W. 
     The specific heating elements and RF generation system (e.g., a magnetron) can vary from embodiment to embodiment, and the elements and system. described above are exemplary only. For example, the upper heater module can include any combination of heaters including combinations of halogen lamps, ceramic lamps, and/or sheath heaters. Similarly, lower heater module can include any combination of heaters including combinations of halogen lamps, ceramic lamps, and/or sheath heaters. In addition, the heaters can all be one type of heater. The specific ratings and number of lamps and/or heaters utilized in the upper and lower modules can vary from embodiment to embodiment. Generally, the combinations of lamps, heaters, and RF generation system is selected to provide the desired cooking characteristics for speedcooking, microwave, and convection bake modes. 
     FIG. 11 is a schematic illustration of oven  100  including an oven rack  219  positioned within cooking cavity  128  for multirack cooking. It is to be understood that the oven floor is also a rack, and, though rack  219  includes two additional racks, there could be only one rack in addition to the oven floor in multirack cooking. When oven  100  is in multirack mode, it is not necessary that every rack in oven  100  contain food items, rather, this only indicates that food items are being prepared on more than one rack. Generally, for the speedcook mode, a user places food in cavity and selects “Speedcook” from control panel  118  and selects multirack mode if desired. The user then uses dial  122  to select a food type and then selects “Start”. Radiant heaters  136  and  138  and convection fan  142  are used to heat the outside of the food, and microwave energy is used to heat the inside of the food. As described below in more detail, the radiant heaters and the magnetron are preferably cycled throughout the cooking cycle to provide the desired cooking results. 
     Some of the cooking options include the further option of a single rack mode or multirack mode. In single rack mode, food is being cooked only on one oven rack. In multirack mode, food items are being cooked on more than one oven rack. Control panel  118  includes a multi light  125 . When the user selects oven/bake a first time, multi light  125  is illuminated indicating that oven  100  is in multirack mode as explained in detail below. When the user selects oven/bake a second time, multi light  125  is not illuminated indicating that oven  100  is in single. rack mode as explained below. 
     The user can toggle between single rack mode and multirack mode. However, in one embodiment, multirack mode is the only mode. In an alternative embodiment, and rather than relying on user input regarding selection of the number of racks on which food is located, at least one sensor senses whether one rack or multiple racks (e.g., by pressure or weight on a rack, or by sensing the presence of baking ware) arc being used and provides an indication of rack mode to an oven controller automatically. Additionally, multirack mode need not be the first mode. For example, when the user selects oven/bake a first time, multi light  125  is not illuminated indicating that oven  100  is in single rack mode, and when the user selects oven bake a second time, multi light  125  is illuminated indicating that oven  100  is in multirack mode. The following functions can be selected from respective key pads  124  of control panel  118 . 
     SPEEDCOOK Selecting this pad enables an operator to perform the following speedcook functions: 1) manually enter speed cooking time, and powerlevels, and select single rack or multirack 2) select preprogrammed control algorithms, or 3)store manually programmed algorithms as recipes 
     OVEN/BAKE Selecting this pad enables an operator to manually enter cooking time and temperature and select single rack or multirack for the oven/bake mode. 
     MICROWAVE Selecting this pad enables an operator to manually enter cooking time and power level for the microwave mode, as well as use pre-programmed microwave features, such as sensor cooking. 
     START/PAUSE Selecting this pad enables an operator to start or pause cooking. 
     CLEAR/OFF Selecting this pad stops all cooking and erases the current program. 
     MICROWAVE EXPRESS Selecting this pad enables an instant 30 seconds of full-power microwave for quick and easy warming of a sandwich, or reheat of coffee. 
     BACK Selecting this pad causes the oven to return to the previous selection. 
     WARM Selecting this pad causes the oven to enter the warming and reheating mode. 
     POWER LEVEL Selecting this pad enables adjusting the power levels for speed cooking and microwave cooking. 
     TIMER Selecting this pad controls a general purpose timer (e.g., minutes and seconds) 
     REMINDER Selecting this pad enables an operator to select a time at which an alarm is to sound. 
     HELP Selecting this pad enables an operator to find out more about the oven and its features. 
     OPTIONS Selecting this pad enables access to the auto night light, beeper volume control, clock, clock display, and display scroll speed features. 
     VENT FAN Selecting this pad enables an operator to clear the cooktop area of smoke or steam. 
     SURFACE LIGHT Selecting this pad turns ON/OFF the surface light for the cooktop. 
     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.