Patent Document

[0001]    This application is a continuation-in-part of pending application Ser. No. 09/329,690 filed Jun. 10, 1999 entitled “A Convection Based Cooking Apparatus with Improved Air Flow.” 
     
    
     TECHNICAL FIELD 
       [0002]    The present invention relates to convection based ovens, grills and similar cooking apparatus and, more specifically, to a convection based cooking apparatus with an internal draft chimney. 
       BACKGROUND OF THE INVENTION 
       [0003]    Convection based cooking apparatus operate on the principle that hot air rises. A heating element generates hot air within a cabinet of the cooking device. The hot air generated by the heating element is drawn over a cooking surface inside the cabinet. Typically, an elongated draft chimney is used as a draft generator to pull air through the cabinet interior. Known draft chimneys are attached to the exterior of a side wall of the cabinet. The heated air that is forced into the chimney rises to the top of the chimney and exits through an opening at the top of the chimney. As the heated air rises through the chimney, a vacuum, similar to a siphon, is generated to draw additional air through the interior of the cabinet. This allows items on the cooking surface to be cooked more quickly. Alternatively, decreasing the rate of airflow through the chimney allows items on the cooking surface to be cooked at a slower rate. 
         [0004]    However, these known draft chimneys attached to the exterior of the cabinet are large and cumbersome. The length of the chimney typically extends approximately two feet above the cabinet. Also, because the chimneys are attached to the exterior side wall of the cabinet, the width of the entire apparatus is increased by at least the width of the chimney. 
         [0005]    Therefore, there is a need in the art for a compact convection based apparatus that does not include a massive, exterior mounted, chimney, but continues to facilitate airflow as described above. 
       SUMMARY OF THE INVENTION 
       [0006]    The present invention solves the above-identified problem by providing an improved draft chimney for convention based cooking apparatus. The improved draft chimney of the present invention is substantially contained within the confines of the cabinet of the cooking apparatus. 
         [0007]    Generally described, the draft chimney of the present invention includes a flue. The flue at least partially defines a path of convection airflow through at least a portion of the interior of a cabinet of the cooking apparatus. The flue passes convection airflow to the exterior of the cabinet. 
         [0008]    In one aspect of the present invention, the draft chimney is entirely defined within the cabinet and the path of convection airflow communicates with the exterior of the cabinet at an end of the path. 
         [0009]    More particularly described, the flue includes opposing first and second openings. The first opening communicates with the cabinet interior and is at least partially defined by at least a portion of a surface of the cabinet interior. Preferably, the first opening is at least partially defined by either a portion of a bottom surface of the cabinet or by the entire width of the bottom surface of the cabinet. 
         [0010]    The foregoing has broadly outlined some of the more pertinent aspects and features of the present invention. These should be construed to be merely illustrative of some of the more prominent features and applications of the invention. Other beneficial results can be obtained by applying the disclosed information in a different manner or by modifying the disclosed embodiments. Accordingly, other aspects and a more comprehensive understanding of the invention may be obtained by referring to the detailed description of the exemplary embodiments taken in conjunction with the accompanying drawings, in addition to the scope of the invention defined by the claims. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0011]      FIG. 1  illustrates a perspective view of one embodiment of the improved draft chimney of the present invention within a convection based grill. 
           [0012]      FIG. 2  illustrates a perspective view of an alternative embodiment of the improved draft chimney of the present invention within a convection based grill. 
           [0013]      FIGS. 3A and 3B  illustrate a side view of the convection based grill of either of  FIGS. 1 and 2 . 
           [0014]      FIG. 4  illustrates a top view of the convection based grill of either of  FIGS. 1 and 2 . 
           [0015]      FIG. 5  illustrates a perspective view of one embodiment of a hood of a convection based grill showing, in particular, a plurality of exit openings for venting airflow from the cabinet through the chimney of the present invention. 
       
    
    
     DETAILED DESCRIPTION 
       [0016]    Referring now to the drawings in which like numerals indicate like elements throughout the several views,  FIGS. 1 and 2  each depict one embodiment of an improved draft chimney  10  of the present invention within a convection based grill  12 . Each convection based grill  12  includes a cabinet  14  with a plurality of surfaces for defining a cabinet interior  16  ( FIGS. 3A and 3B ). The cabinet interior  16  is divided into two chambers by an insulating baffle  18  extending across the longitudinal dimension of the cabinet  14 . The two chambers include a heating chamber  20  and a cooking chamber  22 . 
         [0017]    In the lower portion of the heating chamber  20  is a heating element  24  and a steel flame grate  26  is positioned over the heating element  24 . A cooking surface  28  substantially extends the length and the width of the cooking chamber  22 . The grill  12  is described in greater detail in copending U.S. patent application having U.S. Ser. No. 09/083,416 filed on May 22, 1998 and titled “A CONVECTION BASED COOKING APPARATUS WITH IMPROVED AIRFLOW”, and in copending U.S. patent application having U.S. Ser. No. 09/329,690 filed on Jun. 10, 1999 and titled “A CONVECTION BASED COOKING APPARATUS WITH IMPROVED AIRFLOW”, the entire disclosures of which are incorporated herein by reference. 
         [0018]    Referring now to  FIGS. 3A ,  3 B and  4 , the cabinet  14  is defined by a bottom surface  30 , a front surface  32 , a back surface  34 , a left side surface  36 , and a right side surface  38 . The combination of the bottom surface  30  with lower portions of the front surface  32 , the back surface  34 , the left side surface  36  and the right side surface  38 , defines a lower portion of the cabinet interior, and is commonly referred to as a lower container  40 . Also, the cabinet  14  is further defined by a hood  42 , the interior of which is commonly referred to as an upper cabinet interior, best illustrated in  FIG. 5 . The hood  42  is defined by upper portions of the front surface  32 , the back surface  34 , the left side surface  36 , and the right side surface  38 . 
         [0019]    Still referring to  FIGS. 3A and 3B , the chimney  10  is defined by the right side surface  38 , portions of the front and back side surfaces  32 ,  34 , and an internal surface  50  positioned in substantially a vertical manner. In  FIG. 3A , the internal surface  50  is parallel to the right side surface  38 . In another embodiment, as shown in  FIG. 3B , a portion of the internal surface  50  is parallel to the right side surface  38  and an another portion of the internal surface  50  tapers away from the right side surface  38 . 
         [0020]    As best shown in  FIGS. 1 and 2 , the internal surface  50  has an upper portion  52  and a lower portion  54 . The upper portion  52  is attached to the inside of the hood  42  and the lower portion  54  is attached to the inside of the lower container  40 . When the hood  42  is opened to expose the cabinet interior  16  as shown in  FIGS. 1 and 2 , the draft chimney  10  is separated into two pieces. However, when the hood  42  is closed as shown in  FIGS. 3A and 3B , the upper and lower portions  52 ,  54  are joined together to define the entire length of the draft chimney  10 . The length of the draft chimney is commonly refer to as a flue and is described in greater detail below. 
         [0021]    In order to insure the upper and lower portions  52 ,  54  of the internal surface  50  are properly joined together each time they come into contact with each other, the ends of each portion are bent back in a widthwise manner to define flanges  56  and  58 . The end of the upper portion  52  of the internal surface is bent inward and the end of the lower portion  54  of the internal surface in bent outward toward the right side surface  38  to form a seal when the hood  42  is closed.  FIG. 4  also illustrates the inwardly bent flanges  56 ,  58  of the internal surface  50 . The seal is formed by permitting the upper and lower portions  52 ,  54  to overlap as shown in  FIG. 3A . Alternatively, as shown in  FIG. 3B , the seal could be formed by permitting the flange  56  to directly abut the flange  58  without the upper and lower portions  52 ,  54  overlapping. 
         [0022]    The draft chimney  10  includes an elongated, vertical flue  60  having a first opening  62  and a second opening  64 . The internal surface  50  defines a portion of the flue  60 . Therefore, the flue  60  is separable into two portions as shown in  FIGS. 1 and 2 . Preferably, the flue  60  is prismatic and the length of the flue  60  in the direction of airflow is longer than the width of the flue; however, alternative configurations are also anticipated by the present invention. The first opening  62  communicates with the cabinet interior  16 . Preferably, the first opening  62  is defined between the bottom surface  30  and the end of the vertically positioned internal surface  50  as shown in  FIGS. 1 and 2 . The width of the first opening  62  can extend only a portion of the width of the cabinet  14  as shown in  FIG. 1  or, alternatively, the width of the first opening  62  can extend the full width of the cabinet  14  as shown in  FIG. 2 . 
         [0023]    In operation, ambient air enters the heating chamber  20  through an air inlet  70 . The ambient air is heated and rises through the steel frame grate  26  towards the top of the heating chamber  20 . Eventually, the heated air is forced through an air passage  72  over the baffle  18  into the cooking chamber  22 . As the heated air is forced into the cooking chamber  22 , the cooler air existing the cooking chamber  22  is forced down through the first opening  62  of the flue  60 . The heated air that is forced into the flue  60  of the draft chimney  10  rises to the top and exits through the second opening  64  in the top of the hood  42  to the environment surrounding the cabinet  14 . In the preferred embodiment, a plurality of smaller exit openings combined together to form the second opening  64  as shown in  FIG. 5 . The portion of the surface with the smaller exit openings is commonly referred to as being grilled. 
         [0024]    A path of convection airflow, generally shown by arrows  80   a ,  80   b  and  80   c  in  FIGS. 3A and 3B  is created within the cabinet  14  during operation of the grill  12 . The portion  80   a  of the path begins at the air inlet  70  and proceeds to the passage  72  over the baffle  18  as described above. Then, the path continues through the cooking chamber  22  to pass over the cooking surface  28  in an even manner. This portion of the path is shown by the reference numeral  80   b . Next, the path continues to the first opening  62  of the flue  60  of the draft chimney  10 . The portion  80   c  begins at the first opening  62 , rises to the second opening  64 , and passes into the exterior environment surrounding the grill  12 . Preferably, the draft chimney  10  is entirely defined within the cabinet  14  such that the end of the path  70  communicates with the exterior of the cabinet as best shown in  FIGS. 1-3A  and  3 B. Alternatively, the flue  60  may extend beyond the top of the hood  42  so that a portion of the path of airflow extends beyond the cabinet  16  before exiting to the environment surrounding the grill. 
         [0025]    The present invention has been illustrated in relation to particular embodiments which are intended in all respects to be illustrative rather than restrictive. Those skilled in the art will recognize that the present invention is capable of many modifications and variations without departing from the scope of the invention. Accordingly, the scope of the present invention is described by the claims appended hereto and supported by the foregoing.

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