Patent Abstract:
A gas cooking appliance includes a combination radiant/convection cooking system mounted below a bottom wall portion of an oven cavity. The combination cooking system includes a gas burner in the form of a ring element having a central portion within which is positioned a convection fan. In addition to the convection fan, a forced air combustion fan supplies a combustion airflow to the gas burner. The oven preferably includes a glass panel arranged in a bottom wall portion of the oven cavity, above the gas burner. Arranged about the central opening are a plurality of vented openings for introducing the convective airflow into the oven cavity. The glass panel provides both a conductive heat surface transmitting at least a portion of the radiate heat energy into the oven cavity and a viewing surface allowing a consumer to view the operation of the gas burner.

Full Description:
BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The present invention pertains to the art of cooking appliances and, more particularly, a gas cooking appliance including a combination radiant/convection cooking system employing a gas burner located below a glass panel arranged along a bottom wall of an oven cavity. 
   2. Discussion of the Prior Art 
   In general, combining convection and radiant cooking is well known in the art of gas cooking appliances. In typical arrangements, a convection fan or blower is mounted on a top or rear wall of an oven cavity, while a gas burner is mounted along a bottom wall. With this arrangement, the gas burner radiates heat into the oven cavity while, at  the same time, heats an airflow directed into the oven cavity by the convection blower. 
   Using this construction, in addition to ductwork required for combustion, cooling and exhaust air associated with the gas burner, additional ductwork is needed to carry the heated airflow from the gas burner to and from the convection blower. Obviously, this additional ductwork adds to the overall cost and complexity of the appliance, while also occupying space potentially available for other advantageous features. Furthermore, by transporting heated air through lengthy ducting, the efficiency of the appliance is reduced as a result of heat lost to the ducting and the surroundings. Finally, the need to draw the air from the burner up and into the oven cavity through the ducting increases the power requirement of the convection blower. 
   Based on the above, there exists a need in the art for a cooking appliance which positions the gas burner and blower assembly in close proximity to each other. Moreover, there exists a need in the art for a cooking appliance in which a gas burner is mounted in a protected region of an oven cavity, while still enabling the consumer to view the burner in operation. 
   SUMMARY OF THE INVENTION 
   The present invention is directed to a combination radiant/convection bake gas cooking appliance including a cabinet within which is arranged an oven cavity. Specifically, the appliance includes a  combination radiant/convection cooking system having a gas burner and a convection fan assembly arranged below a bottom wall of the oven cavity. More specifically, the gas burner constitutes a ring burner assembly having a central portion within which is positioned a convection fan or blower. 
   In a preferred embodiment, the cooking system is positioned below a central opening arranged on the bottom wall of the oven cavity. More specifically, arranged about the central opening are a plurality of convection air vents adapted to direct a convective airflow from the cooking system into the oven cavity. In the most preferred embodiment, a glass panel, preferably CERAN glass, is positioned across the central opening. In this preferred embodiment, the glass panel transmits at least a portion of the radiant heat energy from the gas burner to the oven cavity, while allowing a consumer to view the gas burner in operation. In a more preferred embodiment, the convection cooking system, in addition to the convection fan, includes a forced air combustion fan adapted to supply a forced combustion airflow to the gas burner. With this arrangement, the efficiency of the gas cooking system increased. 
   Additional objects, features and advantages of the present invention will become more readily apparent from the following detailed description of a preferred embodiment when taken in conjunction with the drawings wherein like reference numerals refer to corresponding parts in the several views.  

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
       FIG. 1  is a perspective view of a range incorporating a combination radiant/convection gas cooking system constructed in accordance with the present invention; and 
       FIG. 2  is a partial cross-sectional view of the range of  FIG. 1 . 
   

   DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
   With initial reference to  FIG. 1 , a cooking appliance  2  taking the form of a range includes a cabinet shell  4  provided with a cooktop  6 . As illustrated, cooktop  6  is provided with a plurality of gas heating elements  7 – 10  having a corresponding plurality of gas burner grates  11 – 14 . At this point, it should be noted that, although appliance  2  is shown to constitute a free standing gas range, the invention is equally applicable to various other types of types of gas ovens, including slide-in ranges, wall ovens and the like. 
   In a manner known in the art, gas cooking appliance  2  includes a control panel  16 , an interior oven cavity  19  having an associated door  21 , and a lower drawer or bin  24 . More specifically, drawer or bin  24  is adapted to be slid into and out of cabinet shell  4  in order to access an interior storage compartment (not shown) arranged therein. As illustrated, door  21  is adapted to pivot at a lower portion  27  to enable selective access to within oven cavity  19 . In a manner also known in the  art, door  21  is provided with a transparent zone  38  for viewing oven cavity  19  while door  21  is closed. In the embodiment shown, oven cavity  19  includes at least a top panel  31 , a bottom panel  32 , opposing side panels  33  and  34 , and a rear panel  35  (see  FIG. 2 ). Arranged on side panels  33  and  34  are a plurality of baking rack support elements or rails  37 . 
   A plurality of control knobs  42 – 45  for use in selectively activating and deactivating heating elements  7 – 10  respectively, are arranged on a front face portion  48  of cabinet shell  4 . The heating of oven cavity  19  is preferably electronically controlled, with control panel  16  including a display zone  51 , as well as a set of control buttons  54 – 57 , which enable a consumer to select a desired cooking operation, e.g., bake, convection bake, broil, or keep warm operations. In addition, an operational mode cancel button  58 , a light activation button  59  and a self-clean button  60  are provided on one side of display zone  51 . On the opposing side of display zone  51 , there is provided a operating set button  62 , a timer button  63 , cook and stop time buttons  64  and  65 , a clock button  66 , and a number pad  68 . 
   In general, the structure described above with respect to cooking appliance  2  is already known in the art and does not constitute part of the present invention. Therefore, this structure has only been described for the sake of completeness. Instead, the present invention is particularly directed to a combination radiant/convection heating system adapted to establish a heated cooking environment within oven cavity  19 .  
   Referring to  FIGS. 1 and 2 , bottom panel  32  of oven cavity  19  includes a central opening  80 . In the embodiment shown, central opening  80  is defined by an interior ledge portion  82  which supports a removable glass panel  86 . More specifically, glass panel  86  is formed from a heat resistant, substantially transparent material, preferably a high temperature ceramic material such as CERAN. However, other materials having similar qualities are equally acceptable. Although the actual size of opening  80  could vary, the preferred embodiment provides for at least a 12 inch×12 inch (approximately 30.5 cm×30.5 cm) opening  80 . 
   Along a front peripheral portion of central opening  80 , bottom panel  32  includes a downward and forward sloping portion  95  that leads to an upward and forward sloping portion  96 . With this construction, a front depression (not separately labeled) is defined forward of central opening  80 . Arranged in this front depression, specifically along sloping portion  96 , are a plurality of front vent openings generally indicated at  98 . Similarly, extending along a rear peripheral portion of central opening  80  is a downward and rearward sloping portion  103  that leads to an upward and rearward sloping portion  104 . In a manner similar to that illustrated for sloping portions  95  and  96 , a rear depression (not separately labeled) is defined in bottom panel  32  and a plurality of rear vent openings  106  are provided in sloping portion  104 . 
   As best shown in  FIG. 2 , a heating chamber  120 , having at least a bottom wall portion  125  and opposing front and rear wall portions  127  and  128 , is secured to bottom panel  32  of oven cavity  19 . More specifically, heating chamber  120  is secured to bottom panel  32  through attachment flanges  132  and  133 . As illustrated, positioned within heating  chamber  120  is a gas heating system  135  which, when activated, generates heat to be delivered into oven cavity  19 . In the embodiment shown, heating system  135  includes a gas burner  140  constituted by a ring-type burner having an outer peripheral portion  142 , about which extends a plurality of gas outlet vents  143 , and an open central portion  144 . 
   Heating system  135  of cooking appliance  2  also includes a convection fan assembly  150  which can be activated to perform a portion of an overall cooking process. As shown, convection fan assembly  150  includes a convection fan motor  157  operatively connected to a convection fan or blower  165  through a drive shaft  167 . Fan motor  157  is positioned within an air plenum  169  defined by a basin  170  having a bottom portion  171  and opposing side portions  172  and  173  which are secured to bottom wall portion  125 . Of particular note is the positioning of fan  165  within central portion  144  of ring-type gas burner  140 . 
   In the most preferred form of the invention, convection cooking system  150  includes a separate forced air convection system generally indicated at  175 . Forced air convection system  175  includes a forced air convection motor  176  operatively connected to a forced air convection fan or blower  177  arranged within a convection air box  180 . Motor  176  includes a motor shaft  181  drivingly connected to blower  177 . With this arrangement, forced air generated by convection system  175  travels to gas burner  140  through an air supply line  183 . That is, air supply line  183  has a first end  184  interconnected to convection air box  180  and a second end  185  connected to a junction fitting  188 . A gas supply line  190  has a first end  191  adapted to interconnect with a mains gas supply  and a second end  192  interconnected with junction fitting  188 . With this arrangement, forced air generated by convection system  175  and gas from the mains gas supply intermix and are thereafter delivered to gas burner  140  within a burner supply line  195  which extends from an outlet portion of junction fitting  188  to an inlet portion  199  of gas burner  140 . One type of acceptable system is that supplied by WAYNE COMBUSTION SYSTEMS. However, other similarly designed systems would be acceptable. 
   Having described a preferred construction of cooking appliance  2 , a preferred method of operation will now be described. Assuming a combination bake/convection cooking operation is selected through control panel  16 , forced air convection system  175  supplies forced air to burner  140 . Simultaneously, a valve (not shown) is opened allowing gas to flow from the mains supply through supply line  190  to gas burner  140 . At this point, the gas/air mixture is ignited through either a pilot light (not shown) or an electronic ignitor (also not shown). Upon activation, gas burner  140  emits a flame which is visible through glass panel  86 . As gas burner  140  continues to operate, the temperature of glass panel  86  and, by extension, the bottom panel  32  of oven cavity  19  begin to heat, thereby providing radiant heat energy to within oven cavity  18 . 
   Concurrently, electrical energy is supplied to convection fan motor  157  to rotate fan  165  in order to establish convective air streams generally indicated at A. As fan  165  operates, an incoming airflow C is drawn into air intake plenum  169  through a plurality of inlet ports, one of which is illustrated at  205 . Incoming airflow C is subsequently drawn into central portion  144  of gas burner  140  through an intake opening  210  arranged at  least partially about motor drive shaft  167 . With this arrangement, heat energy from gas burner  140  is transferred through a convective heat process to the incoming airflow C forming convective air streams A. As the heat energy transfers from gas burner  140  to air streams A, fan  165  drives heated air streams A from interior cavity  144  of gas burner  140  through front and rear vent openings  98  and  106  into oven cavity  19 . In this manner, food items placed in oven cavity  19  will be subjected to a more uniform cooking environment capable of performing a cooking process in less time than conventional ovens. 
   Although described with reference to a preferred embodiment of the present invention, it should be readily apparent to one of ordinary skill in the art that various changes and/or modifications can be made to the invention without departing from the spirit thereof. For instance, while the convective air inlet vent openings are shown extending along front and rear portions of the glass panel, other arrangements, including having the vents extend entirely about or even through the glass panel, would be acceptable. In addition, while the glass panel is described as having a dimension of 12″×12″ (30.5 cm×30.5 cm), an alternative arrangement would be to construct substantially the entire bottom panel of the oven cavity from glass. In addition to radiant and convection cooking, a microwave system could be added to further reduce the overall cook time. In general, the invention is only intended to be limited by the scope of the following claims.

Technology Classification (CPC): 5