Abstract:
An oven having a heating element cavity including a heating element, an oven cavity including a plurality of inner walls, at least one of which includes a plurality of vertically and horizontally-spaced wall apertures that are in communication with the heating element cavity such that heated air may be received therefrom, and an air circulation mechanism associated with the oven cavity adapted to force air over the inner surface of the at least one inner wall. Each of the wall apertures may be covered by a louver.

Description:
BACKGROUND OF THE INVENTION 
     1. Field of Invention 
     The present invention relates generally to ovens and, more particularly, to ovens with air circulation mechanisms. 
     2. Description of the Related Art 
     Referring to FIG. 1, which is an illustration of a conventional convection oven intended for home use, conventional convection ovens typically include an oven cavity 10 and a heating element cavity 12 which includes a heating element (not shown) such as a gas burner. Oven cavities can be somewhat large. In fact, many oven cavities have a series of racks 14 that allow baking pans to be stacked within the oven cavity. A gap 16 is located between the oven wall 18 and the oven cavity floor 20. Due to the fact that hot air tends to rise relative to cooler air, air which is heated in the heating element cavity 12 travels upwardly into the oven cavity 10 through the gap 16. Some ovens also include small vents 21 in the oven cavity floor that allow heated air to pass into the oven cavity. Eventually, the air will pass through a vent 23. 
     Hot air which enters the oven cavity 10 of conventional convection ovens in this manner is not evenly distributed throughout the oven cavity (i.e. front to back, top to bottom, and side to side). As a result, the food products located therein are not evenly cooked. For example, sheets of cookies baked in a conventional convection oven will often have to be removed, rotated and returned to the oven in order to obtain even baking from cookie to cookie. The baking sheets may also have to be redistributed vertically because the top to bottom heat distribution within the oven cavity is not even. 
     In an attempt to more evenly distribute hot air over the food products within the oven cavity, conventional convection ovens include an air circulation mechanism, such as the fan 22 shown in FIG. 1. The fan 22 creates turbulence and circulates hot air within the oven cavity 10 by drawing air from the center of the oven cavity and then forcing it out from behind a baffle 24 in the manner shown by the arrows in FIG. 1. The fan 22 may also create a small pressure difference between the heating element cavity 12 and the oven cavity 10 which helps draw hot air into the oven cavity. The flow of hot air through the vent 23 also causes upward movement of hot air from the heating element cavity 12 to the oven cavity 10. 
     Most commercially sized convection ovens do not allow hot air into the oven cavity through gaps between the oven cavity wall and floor as shown in FIG. 1. Instead of the gaps, there is an exterior cavity that extends from the heating element cavity, around the exterior of the oven cavity and over the top surface of the oven cavity. A tube, which defines the only connection between the exterior cavity and the oven cavity, extends downwardly through the top surface of the oven cavity to a point adjacent to the fan. The fan draws hot air through the tube and then distributes the hot air in a manner similar to that shown in FIG. 1. 
     While the use of fans has improved heat distribution to some extent, heat distribution within conventional convection ovens intended for home use is still far from optimal. The efficiency of conventional convection ovens intended for commercial use is also far from optimal because the hot air produced in the heating element cavity loses energy as it heats the walls along its somewhat tortured path to the oven cavity. Additionally, conventional commercial convection ovens require a powerful fan to operate in the manner described above. Such a fan produces high pressure within the oven cavity which, in turn, forces much of the hot air out of the oven cavity through the vent. Therefore, a need exists for methods of improving the heat distribution and efficiency of convection ovens. 
     SUMMARY OF THE INVENTION 
     Accordingly, the general object of the present invention is to provide a convection oven which avoids, for practical purposes, the aforementioned problems. In particular, one object of the present invention is to provide a convection oven which distributes heat within the oven cavity in a more even manner than conventional convection ovens. 
     In order to accomplish these and other objectives, an oven in accordance with one embodiment of the present invention includes a heating element cavity including a heating element, an oven cavity including a plurality of inner walls, at least one of which includes a plurality of vertically and horizontally-spaced wall apertures that are in communication with the heating element cavity such that heated air may be received therefrom, and an air circulation mechanism associated with the oven cavity that is adapted to force air over the inner surface of the at least one inner wall of the oven cavity. 
     This aspect of the present invention provides a number of advantages over the prior art. For example, the present invention provides superior front to back, top to bottom and side to side heat distribution than convection ovens known heretofore. The present invention also operates more efficiently than conventional commercial convection ovens because the hot air in the present oven is not forced to travel over the aforementioned tortured path to the oven cavity. Additionally, because the present oven does not require the relatively powerful fan associated with conventional commercial convection ovens, large amounts of hot air is not unnecessarily and inefficiently forced through the vent. 
     In accordance with another advantageous embodiment of the present invention, each of the wall apertures may be covered by a louver. The louvers prevent the air forced over the inner surface of the oven cavity inner wall from interfering with the flow of air through the apertures. 
     The present invention is also applicable to ovens intended for home use as well as those intended for commercial use. 
     The above described and many other features and attendant advantages of the present invention will become apparent as the invention becomes better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Detailed description of preferred embodiments of the invention will be made with reference to the accompanying drawings. 
     FIG. 1 is a perspective view of the interior of a conventional convection oven intended for residential use. 
     FIG. 2 is a perspective view of a convection oven in accordance with a preferred embodiment of the present invention. 
     FIG. 3 is a perspective view of the interior of a convection oven in accordance with a preferred embodiment of the present invention. 
     FIG. 4 is a front view of the interior of a convection oven in accordance with a preferred embodiment of the present invention. 
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT 
     The following is a detailed description of the best presently known mode of carrying out the invention. This description is not to be taken in a limiting sense, but is made merely for the purpose of illustrating the general principles of the invention. The scope of the invention is defined by the appended claims. 
     As illustrated for example in FIGS. 2-4, a convection oven 26 in accordance with a preferred embodiment of the present invention includes a housing 28 having a door 30 and controls 31. The oven also includes a heating element cavity 32 and an oven cavity 34. The heating cavity 32 includes a heating element 36 which, in the exemplary embodiment, is a gas burner and, optionally, a deflector 37. A pair of openings 38 are also provided. The oven cavity 34 is defined in part by inner walls 40, 42 and 44. A pair of passages 46 are formed between inner walls 42 and 44 and the housing 28. Inner walls 42 and 44 also include a plurality of apertures 48 which are spaced front to back and top to bottom along the inner walls. The oven cavity also includes a roof 41 having a vent 43. 
     In the illustrated embodiment, the heating element cavity 32 and oven cavity 34 are separated by a floor 50 which abuts the inner walls 40, 42 and 44. Preferably, the floor 50 abuts the inner walls and creates an air tight seal therewith. Thus, the openings 38, passages 46 and apertures 48 define the only pathway for heated air to travel between the heating element cavity 32 and oven cavity 34. As best seen in FIG. 4, the exemplary inner walls 40, 42, and 44 extend downwardly to the oven base 52 and, therefore, form the walls of the heating element cavity 32. 
     In the exemplary embodiment, the inner walls 40, 42 and 44 are liners, which are formed from materials such as stainless steel or cold rolled steel with a porcelain finish. The housing 28 includes a heat shield 33 as well as insulation 35. 
     An air circulation mechanism 54 is associated with inner wall 40 which, in the illustrated embodiment, is the rearward wall. The exemplary air circulation mechanism 54 draws in air from approximately the center of the oven cavity 34. Some of the air is then forced over inner walls 42 and 44 as shown with the relatively large arrows in FIG. 3. As shown by way of example in FIGS. 3 and 4, the air circulation mechanism 54 includes a fan 56 and a baffle 58. The fan 56 draws air from the center of the oven cavity 34. The exemplary baffle 58, which is primarily composed of a plate that is located in spaced relation to the inner wall 40, defines longitudinal ends 60 and 62, a top end 64 and a bottom end 66. In the exemplary embodiment, the baffle includes a top plate (not shown) that extends to the inner wall 40, thereby preventing air drawn into the baffle 58 by the fan 56 from exiting through the top end 64. Conversely, the side ends 60 and 62 and at least a portion of the bottom end 66 are open so that air drawn into the baffle may flow outwardly therefrom in the manner shown in FIG. 3. 
     In accordance with another aspect of the illustrated embodiment, louvers 68 cover each of the apertures 48. The louvers 68 include downwardly facing openings 70 which allow hot air to pass from the apertures 48 to the oven cavity 34 as illustrated, for example, in FIGS. 3 and 4. During operation, air traveling at a relatively high speed from the longitudinal ends 60 and 62 of the baffle passes over the louvers 68, thereby creating a suction force at the openings 70 which helps draw hot air through the apertures 48. As best seen in FIG. 3, the exemplary louvers 68 include side portions which are generally perpendicular to the inner walls and a curved top portion. Other louver configuration will also produce satisfactory results. For example, a louver may simply consist of a plate which extends from a portion of the oven cavity inner wall adjacent to an aperture 48 and which is located between the aperture and the air circulation mechanism 54. The louvers prevent the air forced over the inner walls 42 and 44 from interfering with the flow of air through the apertures 48. 
     With respect to the number and spacing of the apertures 48 (and louvers 68), there is preferably one row (extending front to back) of apertures above and below each rack. Where, as shown by way of example in FIGS. 3 and 4, there are two racks 72 and 74 on each inner wall, there will be four rows of apertures. In an oven intended for residential use which produces approximately 18 to 30 kBTU, the rows are preferably about 1 to 2 inches above and below the racks. In a commercial oven which produces approximately 20 to 80 kBTU, the vertical aperture to rack spacing is preferably about 2 to 3 inches. Turning to horizontal (or front to back) spacing, the apertures 48 are preferably about 1/2 to 1 inch apart in a residential oven that is approximately 18 to 22 inches deep and about 1/2 to 1 inch apart in a commercial oven that is approximately 20 to 29 inches deep. The apertures themselves are preferably 4 to 6 inches in length and 3/4 to 1 inch in height in both residential and commercial ovens. 
     The oven cavity in the illustrated embodiment is preferably rectangular and, therefore, adjacent inner walls 40, 42 and 44 define 90 degree angles therebetween. In order to redirect air that is forced from the longitudinal ends 60 and 62 of the baffle 58, the air circulation mechanism in illustrated embodiment also includes a pair of deflectors 76. The deflectors 76 insure that the air will be directed over the apertures 48 and louvers 68. 
     Although the present invention has been described in terms of the preferred embodiment above, numerous modifications and/or additions to the above-described preferred embodiments would be readily apparent to one skilled in the art. It is intended that the scope of the present invention extends to all such modifications and/or additions and that the scope of the present invention is limited solely by the claims set forth below.