Abstract:
A lower housing has a fuel grate situated at a predetermined level within the lower housing for supporting a fuel source. The lower housing has a first wall defining a plurality of air intake openings proximate the level of the fuel grate.

Description:
CROSS-REFERENCE TO RELATED CASES 
       [0001]    This application claims the benefit of U.S. provisional patent application Ser. No. 61/739,135 filed on Dec. 19, 2012, and incorporates such provisional application by reference into this disclosure as if fully set out at this point. 
     
    
     FIELD OF THE INVENTION 
       [0002]    The present invention relates to outdoor cooking grills which burn charcoal or other solid fuel and have a kettle-type shape. 
       BACKGROUND OF THE INVENTION 
       [0003]    Kettle-type outdoor cooking grills which burn charcoal are well known in the art. An example of a typical prior art kettle-type grill  2  is illustrated in  FIGS. 1 and 2 . The prior art grill  2  comprises: a hemispherical, bowl-shaped lower housing  4  which has an open top  5  and is supported above the ground at a suitable height by a plurality of legs  6 ; a fuel grate  8  positioned within the lower housing  4  for supporting a bed of charcoal fuel; a cooking grate  10  positioned within the lower housing  4 , possibly at or near the upper opening  5 , above the fuel grate  8 ; a hemispherical cover  12  which is removably positionable on the open top  5  of the lower housing  4  for closing the grill  2 ; one or more adjustable air intake openings  14  positioned in the bottom of the bowl-shaped lower housing  4  of the grill  2 ; and a plurality of adjustable air exhaust openings  15  positioned in the top of the hemispherical cover  12 . 
         [0004]    The prior art grill  2  is operated by first placing a bed of charcoal on the fuel grate  8  and then igniting the charcoal in some manner and allowing the charcoal to burn until the charcoal is converted into a bed of glowing red coals. Next, the food is placed on the cooking grate  10  and can be cooked either with the cover  12  in place over the top  5  of the bowl-shaped lower housing  4  or with the top  5  of the lower housing  4  open. 
         [0005]    Unfortunately, the prior art kettle grill  2  has various significant shortcomings and disadvantages. When exposed to winds of as much as 5 miles per hour, or sometimes less, the flow of the wind across the bottom of the lower housing  4  and across the top of the cover  12  creates negative pressure conditions outside of both the bottom air intake openings  14  and the top air exhaust openings  15 . The creation of a negative pressure condition outside of the bottom air intake openings  14  at least reduces the amount of air flowing into the air intake openings  14  and, in some cases, can create a reverse flow situation wherein air from inside the grill  2  flows out of the bottom air intake openings  14 . 
         [0006]    As a result, the desired upward flow of air through the charcoal bed of the prior art grill  2  is reduced or eliminated, thus slowing or retarding the combustion of the charcoal fuel. Therefore, either the cooking process in the prior art kettle grill  2  is significantly delayed, or the user will attempt to counteract the increased cooking time and reduced cooking temperature caused by the wind by using a significantly greater amount of charcoal. But in either case, the lack of a consistent, positive air flow through the charcoal bed diminishes the ability of the prior art grill  2  to cook by infrared radiation or convection. 
         [0007]    Another problem with the prior art kettle grill  2  is that, even under zero wind conditions, air preferentially flows upwardly from the bottom air intake openings  14  through the center of the charcoal bed. This results in uneven or incomplete burning of the bed and causes the center of the bed to be significantly hotter than the remainder thereof. Consequently, the cooking temperatures produced across the surface of the cooking grate  10  are also very uneven and the time required to adequately combust the entire charcoal bed prior to cooking is increased significantly. 
         [0008]    In addition, because the airflow to a large portion of the charcoal bed is inadequate, the cooking temperatures achieved across at least most of the cooking grate  10  typically are not hot enough to produce attractive sear marks on the food. Moreover, as a further result of the various operational and performance deficiencies listed above, a standard size load of charcoal used in the prior art grill  2  is often effective for cooking only one batch of hamburger patties. 
         [0009]    Another prior art kettle grill  20  described in Danish Patent PA 200101276 is illustrated in  FIG. 3 . The prior art kettle grill  20  illustrated in  FIG. 3  is substantially identical to the prior grill  2  illustrated in  FIGS. 1 and 2  except that air received through the bottom opening(s)  22  of the grill  20  does not flow directly upward through the center of the charcoal bed. Rather, the air received through the bottom openings  22  of the grill  20  is routed through a gap  24  formed between the outer wall  25  of the hemispherical lower housing  26  of the grill  20  and a correspondingly shaped inner liner  28  positioned within the housing  26 . The air flowing through the gap  20  is delivered to a series of ports  30  provided through the inner liner  28  which encircle the outer periphery of the fuel grate  32 . 
         [0010]    The delivery of the combustion air through the surrounding side ports  30 , along with a corresponding circulation of air which is also produced within the center housing  26 , cause the charcoal bed on the fuel grate  32  to burn more evenly as described above with respect to prior art kettle grill  2  of  FIGS. 1 and 2 . In addition the combustion air is preheated as it is delivered through the gap  24  between the outer wall  25  and the inner liner  28  of the bowl-shaped housing  26 . This increases the amount of convective heating occurring thus increases the efficiency of the grill. In this case, the delivery of the combustion air through the gap  24  also operates to cool the inner liner. Consequently, although the amount of convective heating that occurs in the grill  20  is increased, this increase in convective heating is produced at the expense of radiant heating from the inner liner  28 . Since convective heating is in some respects less desirable than infrared heating at these cooking temperatures, the replacement of infrared heating within the prior art kettle grill  20  with convective heating may be detrimental to the overall performance of the unit. 
         [0011]    However, because the air intake openings  22  of the prior art grill  20  are located on the bottom of the cooking bowl  26 , the prior art grill  20  is still highly susceptible to the conditions described above. 
         [0012]    Thus, for the reasons explained above, a need exists for an improved kettle-type grill wherein: (a) the performance of the grill will not be significantly effected even when the grill is operated in winds of up to 5 mph or greater; (b) the charcoal bed within the kettle-type lower housing will burn more evenly; (c) more even temperature and cooking profiles will be achieved at the cooking grate; (d) the temperature at the cooking grate will be increased so that the grill will cook more effectively and will produce attractive sear marks; (e) the charcoal burning time required before cooking will be significantly reduced; (f) the grill will be more efficient and will use less charcoal; and (g) a single load of charcoal will be able to cook from two to three or more times more food than can be cooked by the same load of charcoal in the prior art kettle grills. 
         [0013]    The problems above, and related problems, are addressed by the devices and methods of the present disclosure. 
       SUMMARY OF THE INVENTION 
       [0014]    The invention of the present disclosure, in one aspect thereof, comprises a grill having a lower housing and a fuel grate situated at a predetermined level within the lower housing for supporting a fuel source. The lower housing has a first wall defining a plurality of air intake openings proximate the level of the fuel grate. In some embodiments, a cooking grate is situated above the fuel grate. An upper cover may be positionable on the lower housing to cover the cooking grate and may provide an exhaust opening. A baffle ring may reside in the lower housing, proximate the plurality of air intakes 
         [0015]    In some embodiments, the lower housing has a double walled construction with a second, inner wall providing a plurality of air intake openings. The openings of the inner wall may be vertically proximate the openings of the first wall or may be substantially vertically offset from the openings of the first wall. At least the plurality of openings of the inner wall may be below the fuel grate or the plurality of openings of the first wall and the plurality of openings of the second wall may both be below the fuel grate. 
         [0016]    In other embodiments, the grill further comprises a second wall, interior to the first wall, having at least one opening below the fuel grate and defining a first air passageway between the first and second wall, and a third wall, interior to the second wall, having a termination proximate the fuel grate, and defining a second air passageway between the second and third wall. Air communicates between the first and second air passageways via the at least one opening of the second wall. Air is communicated to the fuel grate at the termination of the third wall. 
         [0017]    The invention of the present disclosure, in another aspect thereof, comprises a grill with a lower kettle housing having a cooking grate supported above a fuel grate in an interior of the housing, and a cover at least partially covering the cooking grate and defining an exhaust opening. The lower housing provides a plurality of air intake openings proximate a level of the fuel grate. In some embodiments, a baffle ring is proximate the plurality of air intake openings and circumscribing at least part of the fuel grate. 
         [0018]    In some embodiments, the housing has a double walled construction comprising an inner wall with a plurality of openings proximate the fuel grate and an outer wall with a plurality of openings proximate those openings of the inner wall. The plurality of openings of the inner wall may be below the fuel grate as may the openings of the outer wall. 
         [0019]    In other embodiments, the grill housing has a double walled construction comprising an outer wall with a plurality of openings proximate a vertical level of the fuel grate and an outer wall with a plurality of openings substantially offset from those openings of the inner wall. In further embodiments, the housing has a triple walled construction with air passing from openings on an outer wall that are proximate a vertical level of the fuel grate to an opening on a middle wall that is below the fuel grate, and air passing thence to a termination of an interior wall proximate the vertical level of the fuel grate. 
         [0020]    The invention of the present disclosure, in another aspect thereof, comprises a method including forming a housing and a cover with an exhaust opening, providing a fuel grate in the housing, providing a cooking grate above the fuel grate, and creating a plurality of openings in the housing proximate a vertical level of the cooking grate. 
         [0021]    The method may further comprise providing a baffle ring within the housing proximate the plurality of openings. Forming a housing may further comprise forming a double walled housing, and creating a plurality of openings in the housing may further comprise forming a plurality of openings in an outer wall proximate a vertical level of the cooking grate. Forming a housing may further comprise forming a triple walled housing, and creating a plurality of openings in the housing further comprises forming a plurality of openings in an outer wall proximate a vertical level of the cooking grate. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0022]      FIG. 1  is a perspective view of a prior art kettle grill  2 . 
           [0023]      FIG. 2  is a cutaway elevational view of a kettle-type lower housing  4  of the prior art grill  2 . 
           [0024]      FIG. 3  is a cutaway elevational view of a kettle-type lower housing  26  of a prior art kettle grill  20 . 
           [0025]      FIG. 4  is a perspective view of an embodiment of grill  100  according to the present disclosure. 
           [0026]      FIG. 5A  is a cutaway elevational view of the grill  100 . 
           [0027]      FIG. 5B  is an cutaway elevational view of the grill  100 . 
           [0028]      FIG. 6  is a perspective view of another embodiment a grill  200  according to the present disclosure. 
           [0029]      FIG. 7  is a cutaway elevational view of another embodiment of a grill  300  according to the present disclosure. 
           [0030]      FIG. 8  is a cutaway elevational view of another embodiment of a grill  400  according to the present disclosure. 
           [0031]      FIG. 9  is a cutaway elevational view of another embodiment of a grill  500  according to the present disclosure. 
           [0032]      FIG. 10  is a cutaway elevational view of another embodiment of a grill  600  according to the present disclosure. 
       
    
    
     DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS 
       [0033]    The grills of the present disclosure satisfy the needs and alleviate the problems discussed above, and others. Various embodiments of the present disclosure provide kettle-type cooking grill comprising: (a) a kettle-type lower housing which has a heating chamber therein and an open upper end; (b) a fuel support grate positionable within the heating chamber; (c) a food support grate positionable above the fuel grate; (d) a top cover which is removably positionable over the upper opening of the lower housing; and (e) one or more air exhaust openings provided in the top of the cover. One improvement to the cooking grill comprises a plurality of air intake openings which are formed through and substantially around an upwardly extending portion of an outer wall of the kettle-type lower housing such that the air intake openings substantially surround the heating chamber. 
         [0034]    The air intake openings are preferably located substantially in a horizontal plane which extends traversely through the lower housing at a similar level as the food support grate and above the bottom of the heating chamber. The air intake openings are more preferably located substantially in a horizontal plane which is not more than 3 inches below the fuel grate and not more than 3 inches above the fuel grate. 
         [0035]    Further aspects, features, and advantages of the present invention will be apparent to those of ordinary skill in the art upon examining the accompanying drawings and upon reading the following detailed description of the preferred embodiments. 
         [0036]    An exemplary preferred embodiment of a grill  100  is illustrated in  FIGS. 4 ,  5 A and  5 B. The grill  100  comprises: a generally hemispherical kettle-type lower housing  102  having an open top  104 ; a heating chamber  105  defined within the lower housing  102 ; a plurality of legs  106  or other support structure which supports the lower housing  102  above the ground; a fuel grate  108  which is removably positioned in the heating chamber  105  for supporting a bed of charcoal or other solid fuel  107 ; a cooking grate  110  which is removably positionable above the fuel grate  108  at a location within the heating chamber  105  possibly at or near the open top  104  of the lower housing  102 ; a cover  112  which is removably positionable on the lower housing  102  over the open top  104  thereof; a series of perforations or air intake openings  114  which are formed laterally around and through an upwardly extending portion of outer wall  116  of the lower housing  102  such that the openings  114  preferably encircle or otherwise traversely surround the heating chamber  105  within the lower housing  102 ; one or more (preferably a plurality of) air exhaust openings  118  formed through the top of the cover  112 ; and one or more (preferably a plurality of) dampers or shutter plates  120  movably attached to the top of the cover  112  for selectively opening, closing, or partially closing the air exhaust openings  118  to any degree desired. 
         [0037]    As used herein, and in the claims, the term “kettle-type lower housing” refers to a grill bottom structure which contains and defines the heating chamber wherein charcoal or other solid fuel is placed and burned and which is shaped such that, along at least 90% of the vertical height of the lower housing structure, the horizontal cross-sectional shape of the lower housing structure is generally circular. More preferably, the horizontal cross-sectional shape of the lower housing structure along substantially the entire vertical height thereof will be circular or substantially circular. Consequently, by way of example, but not by way of limitation, a “kettle-type lower housing” could have: (a) hemispherical or generally hemispherical shape, (b) a paraboloid shape, (c) a frustoconical or generally frustoconical shape, (d) a cylindrical or generally cylindrical shape, or (e) a combination thereof. Despite the foregoing, it is understood that in some embodiments, the lower housing  102  may be of a shape that departs from what might be considered a kettle type lower housing and relies instead upon various shapes and geometries as are known to those of skill in the art. 
         [0038]    The air intake openings  114  of the grill  100  are preferably positioned in substantially a horizontal plane  122 , which extends transversely through the kettle-type lower housing  102 . The horizontal plane  122  is preferably located at a similar level to the cooking grate  110  and above the bottom  115  of the heating chamber  105 . The horizontal plane  122  is more preferably located at an elevation of anywhere from about 2 inches below to about 2 inches above the fuel grate  108  and is most preferably located at an elevation in the range of from about 1 inch below to about 1 inch above the fuel grate  108 . 
         [0039]    In the grill  100 , as illustrated in  FIGS. 4 and 5 , the air intake openings  114  are positioned elevationally above the fuel grate  108  and encircle the heating chamber  105 . The air intake openings  114  place the heating chamber  105  in direct fluid communication with the air outside of the upwardly extending outer wall  116  of the lower housing  102  such that the outside air is allowed to flow horizontally directly through the air intake openings  114  into the interior heating chamber  105 . 
         [0040]    The lower housing  102  can be of a single wall, double wall, partial double wall, or even a triple wall construction. A double wall or partial double wall construction will help to (a) prevent heat loss, (b) increase the radiating temperature of the inner wall of the lower housing, and (c) shield the outer wall of the lower housing  102  from direct exposure to the heating chamber  105  to thereby reduce the temperature of the outer wall. 
         [0041]    As illustrated in  FIG. 5A , the lower housing  102  of the grill  100  includes an inner lining wall  124  which can be a permanent liner or can operate as a removable ash pan which only covers a lower portion of the interior of the lower housing  102  below the air intake openings  114 . If the inner lining wall  124  is a removable ash pan, it will also be understood that the grill  100  can be operated either with or without the ash pan in place. Alternatively, the inner liner could be a removable or permanent liner which covers substantially the entire interior of the lower housing  102  such that the air intake openings  114  would extend directly through both the outer wall and the inner liner of the lower housing  102  into the heating chamber  105 . 
         [0042]    If desired, in order to adjust the amount of air flowing into the heating chamber through the air intake openings  114 , a thin, sliding, sheet metal shutter (or other selective opening) can be provided for opening, closing, or partially restricting the air intake openings  114 . 
         [0043]    Although the air intake openings  114  of the grill  100  are circular in shape, it will be understood that the openings can be in the form of squares, rectangles, slits or other shapes and can be of any desired size, number, and spacing suitable for providing sufficient outside air to the heating chamber  105  for combustion of the charcoal or other solid fuel  107 . 
         [0044]    In windy conditions, in the present embodiment, the positioning of the air intake openings  114  through an upwardly extending portion of the outer wall  116  of the lower housing  102  allows the direct horizontal flow of outside air into the heating chamber  105  through the particular openings  114  which are directly facing the wind (i.e., for reference purposes, are facing into the wind at a downward angle of 0° and a sideways angle of 0°) or are at least facing the wind at a downward angle of preferably not more than 75° and/or a right or left sideways angle of preferably not more than 75°. To summarize, various embodiments of grills of the present disclosure produce a positive flow of air into the heating chamber below the cooking grate even in the presence of wind. Moreover, regardless of whether the grill is operated under windy conditions or with no wind, the incoming flow through the openings  114 , along with the circulation of the air in the center of the heating chamber  105  which this flow also produces, provides a more uniform flow of air to the entire fuel grate  108  than is provided in the prior art kettle grills. 
         [0045]    The more uniform distribution of air across the entire fuel grate  108 , and the more uniform combustion which it produces, also operate to provide more uniform temperatures and cooking conditions at the cooking grate  110  and to significantly increase the temperature at the cooking grate  110 , even under any wind conditions. Consequently, with or without wind, the food will cook more rapidly at a higher temperature in the grill  100  so that the cooking performance is significantly enhanced and attractive searing marks can be produced. 
         [0046]    The grill  100  is also much more stable under windy conditions and is much less susceptible diminution in cooking efficacy or other problems due to wind. Because the air intake openings  114  of the grill  100  are located near to and around the fuel grate  108 , a positive pressure is created at the air intake openings  114  which face or partially face the wind. Thus, not only will the flow of air through these openings  114  and across the fuel grate  108  continue even under sustained winds of 5 mph, 10 mph or more, but the amount of air flowing through the windward openings will increase and will compensate for the reduction of flow which may occur through the remaining air intake openings which are located on the opposite side of the grill or which face in a direction which is substantially perpendicular to the direction of the wind. Consequently, not only does the grill  100  substantially ensure against charcoal blowout, but a high level of combustion resulting in a high level of infrared heat transfer to the food is maintained. 
         [0047]    The cooking grate  110  used in the grill  100  can be (a) a wire mesh or other type of open convective food support grate or (b) an infrared re-emitting food support grate of any desired single or multiple piece construction. The cooking grate  110  will preferably be an infrared food support grate which is placed close to (i.e., within about 3 inches of) the fuel grate  108 . Placing the cooking grate  110  in close proximity to the fuel bed  107  significantly increases the thermal efficiency of the grill  100 . 
         [0048]    The fuel grate  108  can be any type of perforated pan, perforated tray, wire grate, or other structure which is used in cooking grills for supporting a bed of charcoal or other solid fuel. The fuel grate  108  will preferably be a porcelain-coated or stainless steel wire grate having gaps between the support wires in range of from about 0.25 to about 0.5 inch. 
         [0049]    Also shown in  FIG. 5A  is the baffle ring  119 , which extends around the inside of the heating chamber, generally on a plane common to the combustion air intake openings  114 . The ring may circumscribe all of a portion of the fuel grate  102 . This ring can be incorporated in some embodiments to prevent ash and sparks from flowing out through downstream air inlet holes in windy conditions but will not necessarily need to be used in all embodiments. The dimensions, spacing, and construction of this ring for may be varied according to normal engineering practice so long as the result of arresting at least some sparks, embers, and/or ash from flowing out of the housing  102  is achieved. 
         [0050]    Another embodiment  200  of a grill according to the present disclosure is illustrated in  FIG. 6 . The grill  200  is substantially identical to the grill  100  except that the kettle-type lower housing  202  of the grill  200  does not have a hemispherical shape but instead comprises a lower frusto-conical portion  204  and an upper cylindrical portion  206 . In addition, the bottom  208  of the kettle  202  of the grill  200  is a removable ash pan which has a handle  210  extending therefrom which the user can grasp for rotating the ash pan  208  to a locked position on the bottom of the kettle  202 . After use, the ash pan  208  can be rotated to an unlocked position in order to remove the ash and food debris which have collected on the pan  208 . 
         [0051]    Another alternative embodiment  300  of the grill is illustrated in  FIG. 7 . The kettle-type lower housing  302  of the grill  300  differs from that of the grill  100  in that the interior of the lower housing  302  is entirely covered by a lining structure  306  comprising: an upper portion  308  which receives air from the air intake openings  310  provided through the outer wall  312 ; a lower portion  314  which is preferably removably positioned within the lower portion of the lower housing  302  to operate as a removable ash pan; and an air flow gap or a plurality of interior air flow openings  316  formed between the upper portion  308  of the liner and the ash pan  302 . 
         [0052]    The interior air openings  316  of the inner lining structure  306  are positioned elevationally below the air intake openings  310  provided in the outer wall  312  so that the combustion air flowing into the intake openings  310  flows downwardly through a gap  318  formed between the upper portion  308  of the inner liner and outer wall and is discharged by the interior openings  316  into the heating chamber  305  at a location below the fuel grate  320 . It will be appreciated that, in this embodiment, a baffle ring  119  may not be needed. 
         [0053]    Another alternative embodiment  400  of the grill is illustrated in  FIG. 8 . The grill  400  differs from the grill  100  in that the kettle-type lower housing  402  of the grill  400  is of a triple-walled construction wherein air is received through air intake openings  406  formed through the outer wall  408  at a location at or above the fuel grate  409  and flows downwardly behind a first inner wall  410  to an opening  412  provided in the bottom of the kettle. The air then flows upwardly through a gap  414  formed between the first inner wall  410  and a second inner wall  415  and is released from the circular upper end  416  of the gap  414  around the outer periphery of the fuel grate  409 . Thus the innermost wall  415  may be said to terminate proximate the fuel grate  409 . 
         [0054]    Another alternative embodiment  500  of the grill is illustrated in  FIG. 9 . The grill  500  differs from the grill  100  in that air is received through intake openings  504  located in the outer wall  506  of the kettle-type lower housing  508  at a location below the fuel grate  510  and flows directly through corresponding interior openings  512  formed in an inner liner  514  which are also located below the fuel grate  510 . 
         [0055]    It will be seen that the variations  300  and  500  shown in  FIGS. 7 and 9  illustrate that in the context of a double walled construction the air openings ( 310 ,  504 ) in the outer wall ( 312 ,  506 ) can be offset from the air openings ( 316 ,  512 ) in the inner wall ( 306 ,  514 ), or aligned with the openings in the inner wall. In some cases they may be substantially vertically offset (for purposes of this disclosure, this means that air passing from outside to inside the housing ( 202 ,  302 ,  402 , etc.) is required to take a tortured path as shown in  FIGS. 7 and 8 ). The air openings in the outer wall can be above the level of the fuel grate or below the level of the fuel grate as previously disclosed and the air openings in the inner wall can be above or below the level of the fuel grate as similarly disclosed. Any combination of relative position of air openings that prevents wind from starving the fuel of oxygen will be effective and/or provides air supply to the fuel may be suitable. 
         [0056]    Another alternative embodiment  600  of the grill is illustrated in  FIG. 10 . The grill  600  differs from the grill  100  in that both the kettle-type lower housing  602  and the cover  604  of the grill  600  are of a double-walled construction. In addition, the grill  600  includes a charcoal lighter can  606  which is removably attachable to the bottom of the lower housing  602  for holding crumpled newspaper or other combustible material which can be burned in the can  606  for igniting the charcoal or other solid fuel placed on the fuel grate  610 . The can  606  includes inlet air openings  612  having dampers or shutters thereon such that the openings  612  can be opened for burning the newspaper or other starter material and then closed during operation after the charcoal on the fuel grate  610  is ignited so that all combustion air for consumption of charcoal once lit is provided by the openings such as  114 , shown in  FIGS. 4 and 5 , openings such as  318  and  316  found in  FIG. 7 , etc. 
         [0057]    Thus, the present invention is well adapted to carry out the objectives and attain the ends and advantages mentioned above as well as those inherent therein. While presently preferred embodiments have been described for purposes of this disclosure, numerous changes and modifications will be apparent to those of ordinary skill in the art. Such changes and modifications are encompassed within the invention as defined by the claims.