Patent Publication Number: US-2011067685-A1

Title: Gas-Fueled Food Cooker with a Sealed Heating Conduit

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
     This application claims benefit of U.S. provisional application Ser. No. 61/272,442 filed Sep. 23, 2009, and entitled “Sealed Gas Heating Source For Gas Fired Food Cookers,” which is hereby incorporated herein by reference in its entirety for all purposes. 
    
    
     STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT 
     Not applicable. 
     BACKGROUND 
     This disclosure relates generally to a gas-fueled food cooker, such as an outdoor gas grill. More particularly, the disclosure relates to a food cooker having an enclosed heating conduit. 
     Gas grills are commonly used to prepare food outdoors. Typically the gas grill includes a grill body, or bottom tray, and a grill hood, which together form a cooking chamber. One or more cook grids are supported within the cooking chamber to create a cooking surface. At least one burner is disposed within the cooking chamber beneath the cooking surface. Each burner includes a plurality of burner ports. When the gas grill is operational, an air-fuel mixture exits the burner ports and is ignited to create flame, which is the source of heat for cooking. 
     During operation of the gas grill, food is placed on the cooking surface and manually moved or turned from time to time until ready. As the food is moved on the cooking surface, the open flame below it creates a safety hazard to the cook. Further, the food is exposed to exhaust fumes created by the flame, which may adversely affect the taste of the food. As the food cooks, drippings from the food, such as grease, fall onto the burners below. Over time, the drippings cause corrosion of the burners until they must be replaced. 
     Accordingly, there is a need for a heat source that eliminates the risk to safety posed by the open flame inside a gas grill and the exposure of food to exhaust fumes during cooking. It would be particularly desirable if the heating source were more resistive to corrosion than conventional burners. 
     SUMMARY OF THE PREFERRED EMBODIMENTS 
     A cooker for preparing food is disclosed. In some embodiments, the cooker includes a cooking chamber and a heating conduit extending through the cooking chamber. The heating conduit has an enclosed combustion chamber. 
     In some embodiments, the cooker includes a cooking chamber, a heating conduit, and a fuel source. The heating conduit extends through the cooking chamber and has an enclosed combustion chamber and a fuel inlet in fluid communication with the fuel source. 
     In some embodiments, the cooker includes a cooking chamber and a heating conduit. The heating conduit has a first portion and a second portion. The first portion extends through the cooking chamber and has an enclosed combustion chamber. The second portion is external to the cooking chamber and has a fuel inlet and an air inlet. 
     Thus, embodiments described herein comprise a combination of features and advantages intended to address various shortcomings associated with conventional gas grills. The various characteristics described above, as well as other features, will be readily apparent to those skilled in the art upon reading the following detailed description of the preferred embodiments, and by referring to the accompanying drawings. 
    
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
       For a detailed description of the disclosed embodiments, reference will now be made to the accompanying drawings in which: 
         FIG. 1  is front view of a gas-fueled food cooker in accordance with various principles disclosed herein; 
         FIG. 2  is front view of the gas-fueled food cooker of  FIG. 1  with the grill hood open, exposing to view the cook grids and cooking surface; 
         FIG. 3  is an enlarged view of the cook grids of  FIG. 2 ; 
         FIG. 4  is an enlarged view of the heating conduits of  FIG. 3 ; 
         FIG. 5  is a schematic representation of one heating conduit of  FIG. 1 ; and 
         FIG. 6  is a perspective view of the fuel supply assembly of  FIG. 1 . 
     
    
    
     DETAILED DESCRIPTION OF THE DISCLOSED EMBODIMENTS 
     The following description is directed to exemplary embodiments of gas-fueled food cookers. The embodiments disclosed should not be interpreted, or otherwise used, as limiting the scope of the disclosure, including the claims. One skilled in the art will understand that the following description has broad application, and that the discussion is meant only to be exemplary of the described embodiments, and not intended to suggest that the scope of the disclosure, including the claims, is limited to those embodiments. 
     Certain terms are used throughout the following description and claims to refer to particular features or components. As one skilled in the art will appreciate, different persons may refer to the same feature or component by different names. This document does not intend to distinguish between components or features that differ in name but not function. Moreover, the drawing figures are not necessarily to scale. Certain features and components described herein may be shown exaggerated in scale or in somewhat schematic form, and some details of conventional elements may not be shown in interest of clarity and conciseness. 
     In the following discussion and in the claims, the terms “including” and “comprising” are used in an open-ended fashion, and thus should be interpreted to mean “including, but not limited to . . . . ” Also, the term “couple” or “couples” is intended to mean either an indirect or direct connection. Thus, if a first device couples to a second device, that connection may be through a direct connection, or through an indirect connection via other devices and connections. 
     Referring now to  FIG. 1 , there is shown an embodiment of a gas-fueled food cooker in accordance with the principles disclosed herein. Gas-fueled food cooker  100  includes a cooking chamber  105 , a support frame  110 , a fuel source  115 , two heating conduits  120 , and a fuel supply assembly  125 . Frame  110  supports cooking chamber  105  at a convenient height above the ground. In this exemplary embodiment, support frame  110  includes a support post  130  coupled between the base of cooking chamber  105  and a wheeled frame  135 . Wheeled frame  135  enables mobility of food cooker  100 . In other embodiments, support frame  110  may include only support post  130 , and further support post  130  may be permanently mounted in the ground, for instance, proximate an edge of a patio. In such cases, food cooker  100  is immobile. 
     Cooking chamber  105  is formed by a grill body  140  and a grill hood  145  coupled thereto. Grill hood  145  is pivotable relative to grill body  140  between a closed position and an open position. In the closed position, shown in  FIG. 1 , grill hood  145  abuts grill body  140 , and cooking chamber  105  is enclosed. In the open position, shown in  FIG. 2 , grill hood  145  does not abut grill body  140 , and cooking chamber  105  is accessible. As best viewed in  FIG. 3 , food cooker  100  further includes two cook grids  150  disposed within cooking chamber  105 . Cook grids  150  are accessible when grill hood  145  is in the open position. Further, cook grids  150  are disposed above heating conduits  120  and form a cooking surface  155  upon which food is placed for cooking. 
     Referring now to  FIG. 1  and  FIG. 4 , in which cook grids  150  are removed, each heating conduit  120  is supported by grill body  140  and extends through cooking chamber  105 . The heating conduit  120  is welded, or otherwise coupled, to grill body  140  such that a portion  122  of the heating conduit  120  is disposed within cooking chamber  105  and another portion  124  of the heating conduit  120  is disposed outside of cooking chamber  105 . The portion  122  of heating conduit  120  disposed within cooking chamber  105 , or interior portion  122  of heating conduit  120 , is best viewed in  FIG. 4 . The portion  124  of heating conduit  120  disposed outside of cooking conduit  105 , or exterior portion  124  of heating conduit  120 , is best viewed in  FIG. 1 . 
     Turning to  FIG. 5 , which is a schematic representation of the heating conduit  120 , the heating conduit  120  is a tubular and has an internal combustion chamber  165  extending between a first end  170  (see also  FIG. 1 ) and a second end  175 . Heating conduit  120  has a fuel inlet  180  at first end  150 . Fuel is introduced into combustion chamber  165  through inlet  180 , as will be described. Heating conduit  120  further includes one or more air inlets  185  spaced apart from fuel inlet  180 . In the illustrated embodiment, air inlets  185  are rectangular in shape. However, in other embodiments, air inlets  185  may be differently shaped. Fuel and air inlets  180 ,  185  are disposed in exterior portion  124  of heating conduit  120 . As such, fuel and air inlets  180 ,  185  are external to cooking chamber  105 . 
     Air is introduced into combustion chamber  165  through inlets  185 . In preferred embodiments, air passively flows through inlets  185  into combustion chamber  165 . Inside combustion chamber  165 , the air combines with fuel therein to form an air-fuel mixture that is subsequently ignited. Due to the pressure of fuel supplied by fuel source  115 , the air-fuel mixture flows through heating conduit  120  as the air-fuel mixture burns within combustion chamber  165 . At second end  175 , heating conduit  120  has an exhaust outlet  190 . Exhaust outlet  190  is substantially flush with the exterior surface of grill body  140 . Fumes created by combustion of the air-fuel mixture within heating conduit  120  are exhausted from heating conduit  120  through exhaust outlet  190  to the atmosphere surrounding food cooker  100 . 
     Air inlets  185  are positioned relative to fuel inlet  180  such that the center  187  of each air inlet  185  is a distance  189 , as measured along the longitudinal axis of heating conduit  120 , from fuel inlet  180 . In preferred embodiments, distance  189  equals 4 1/32 inches, the cross-sectional area of fuel inlet  180  is 7.65 square inches, and the sum of the cross-sectional areas of all air inlets  185  is 9.96 square inches. The preferred dimensions enable an optimum air-fuel mixture. 
     As best viewed in  FIG. 4 , heating conduit  120  is coupled to grill body  140  along a first attachment edge  162  and along a second attachment edge  164 . Interior portion  122  of heating conduit  120  has a length  160 . Length  160  is the distance between first attachment edge  162  and second attachment edge  164  as measured along the longitudinal axis of heating conduit  120 . 
     Length  160  of heating conduit  120  is selected to provide a substantially uniform heat flux rate to cooking surface  155  ( FIG. 3 ). Depending on the size of cook grids  150 , this may require that heating conduits  120  extend the length of cook grids  150  and back again, as shown in  FIG. 3 . Providing a uniform rate of heating to cooking surface  155  enables food placed thereon to cook efficiently and consistently, regardless of its position on cooking surface  155 . Furthermore, length  160  is selected such that the fuel contained in the air-fuel mixture within combustion chamber  165  is substantially consumed before reaching second end  175  of heating conduit  120 . This enables fuel introduced at inlet  180  to be completely combusted, and the associated heat produced utilized for cooking purposes, rather than exhausted from outlet  190  and wasted. 
     Heating conduit  120  has a cross-sectional area  195  defined normal to length  160 . In the illustrated embodiment, cross-sectional area  195  is rectangular in shape. In other embodiments, heating conduit  120  may be configured such that cross-sectional area  195  has another shape, such as but not limited to circular, square, or oval. 
     The interior portions  122  of heating conduits  120  are sealed. As such, combustion chambers  165  of heating conduits  120  are enclosed. As used herein, the expression “enclosed combustion chamber” means that there is no gas flow path between combustion chamber  165  and the portion of cooking chamber  105  surrounding heating conduits  120 , and that the flames within heating conduits  120  are inaccessible through cooking chamber  105 . Consequently, the flames are inaccessible to a cook during operation of food cooker  100 . Moreover, fumes created by combustion of the air-fuel mixture within combustion chambers  165  are prevented from escaping combustion chambers  165  into the interior of cooking chamber  105  surrounding heating conduits  120 . Instead, the fumes exhaust from heating conduits  120  through exhaust outlet  190 . Hence, food placed on cook grids  150  is not exposed to the fumes during operation of food cooker  100 . 
     Fuel source  115  is coupled to fuel inlet  180  by fuel supply assembly  125 . Source  115  provides fuel for heating or cooking of food placed on cook grids  150 . In the illustrated embodiment, fuel source  115  is a tank containing fuel, such as but not limited to natural gas or liquid propane. Tank  115  is releasably coupled to and supported by wheeled frame  135 . In other embodiments, fuel source  115  may be an in-ground propane tank or natural gas line. 
     As best viewed in  FIG. 6 , fuel supply assembly  125  includes a tank coupling  205 , a flexible fuel hose or supply line  210 , two valves  215 , two flexible fuel hoses or supply lines  220 , two jet nozzles  225 , and two support plates  230 . Tank coupling  205  is configured for releasable connection to fuel source  115 . Fuel supply line  210  is coupled between tank coupling  205  and valves  215 . Each fuel supply line  220  is coupled between one valve  215  and one jet nozzle  225 . Valves  215  are actuatable to control or adjust the flow of fuel therethrough. Each nozzle  225  extends through and is supported by one plate  230 . Each support plate  230  is configured for coupling to end  170  of one heating conduit  120  such that support plate  230  covers fuel inlet  180  with nozzle  225  extending into heating conduit  120 . In the illustrated embodiment shown in  FIG. 1 , support plates  230  are bolted to flanges  235  extending around the peripheries of heating conduits  120  at ends  170 . Moreover, in preferred embodiments, the outlet  240  of each nozzle  225  is disposed 0.5 inches from end  170  of heating conduit  120 . 
     During operation of food cooker  100 , fuel source  115  supplies fuel through supply line  210 , valves  215 , supply lines  220 , and nozzles  225  of fuel supply assembly  125  into heating conduits  120  at a desired rate. The rate at which fuel is supplied to heating conduits  120  may be adjusted by actuation of valves  215 . In preferred embodiments, the rate at which fuel is supplied to heating conduits  120  is no greater than 2.13 ounces per minute. As previously described, the injected fuel mixes with air inside heating conduits  120 . The air-fuel mixture is subsequently ignited and burns. In some embodiments, an end of a handheld butane gas lighter is inserted through one air inlet  185  and actuated to ignite the air-fuel mixture in each heating conduit  120 . Heat produced by combustion of the air-fuel mixture is conducted through the wall(s) of heating conduits  120  and then radiated into cooking chamber  105 , including food placed on cook grids  150 . Periodically, grill hood  145  is opened and the food is flipped or moved relative to cook grids  150 . During such movements, the cook remains unexposed to flames which are contained within heating conduits  120 , enabling reduced risk to the cook, as compared to that posed by the open flames of conventional gas grills. As the food is heated or cooked, the food remains isolated from fumes within heating conduits  120 , also in contrast to conventional gas grills having an open flame. 
     In the illustrated embodiment, food cooker  100  has two heating conduits  120  supported below two cook grids  150  within cooking chamber  105 . In other embodiments, the food cooker may include a different number of cook grids. Similarly, in other embodiments, the food cooker may include a different number of heating conduits. For example, the food cooker may include only a single heating conduit spanning the cooking chamber from end to end. In such embodiments, the fuel supply assembly would be modified accordingly. 
     While various embodiments have been showed and described, modifications thereof can be made by one skilled in the art without departing from the spirit and teachings herein. The embodiments herein are exemplary only, and are not limiting. Many variations and modifications of the apparatus disclosed herein are possible and within the scope of the invention. Accordingly, the scope of protection is not limited by the description set out above, but is only limited by the claims which follow, that scope including all equivalents of the subject matter of the claims.