Abstract:
A solid fuel smoker oven having a cooking chamber and a heat source chamber separated by a vertical divider. The heat source chamber includes a gas fired firebox to burn solid fuel. The cooking chamber comprises air channels defined by perforated wall panels comprising calibrated orifices that vary in size from the top of the channel to the bottom to allow air flow and temperatures inside the cooking chamber to be balanced. A fan in the cooking chamber draws heat and smoke emissions from the firebox and directs them into the air channels and recycles the heated air and smoke through the heat source chamber, which limits heat and smoke escape and maximizes temperature stability inside the oven. The fan also functions as a spark arrestor.

Description:
RELATED APPLICATIONS 
       [0001]    This application claims the benefit of U.S. provisional patent application Ser. No. 61/993,104 filed May 14, 2014 which is incorporated herein by reference. 
     
    
     BACKGROUND 
       [0002]    The invention relates generally to ovens for preparing food products, and more particularly to an oven or smoker. 
         [0003]    Food products, for example meats such as beef, pork, and poultry, as well as fish and the like, traditionally are prepared for consumption by subjecting the raw product to sufficient heat so as to cook the product to an appropriate level of doneness. Various ovens or cookers are used for roasting, broiling, smoking or barbequing meat. In many instances, the cookers or ovens used to prepare the product have a cooking chamber and a source of convection heat, for example, electric heating elements, gas jets, wood or charcoal burners. In commercial food preparation, for example in restaurants, large ovens are employed to cook or prepare large quantities of product at one time. For example, large convection ovens or barbeque ovens or smokers are used to prepare batches of food products, such as roasts, ribs, chickens, fish and sometimes potatoes and other vegetables. These products generally are placed on racks inside the cooking chamber and subjected to heat and/or smoke. These commercial ovens, particularly barbeque ovens or smokers, usually impart a unique and desired flavor and quality to the prepared foods. 
         [0004]    Most commercial ovens or smokers function well for their intended purposes. However, the commercial ovens or smokers generally are fixtures in a restaurant or other food preparation facility. They are large, heavy and often connected to a source of fuel, such as natural gas and electricity. Also, to be used in a commercial setting, the oven must be installed under a Type 1 commercial ventilation system. 
         [0005]    It would be advantageous, therefore, to provide a compact oven or smoker for preparation of food products that provides many of the same cooking features as a larger commercial oven or smoker. 
         [0006]    It would be advantageous to provide such a compact smoker oven with a heat and smoke source separate from the cooking chamber. 
         [0007]    It also would be advantageous to provide a compact smoker oven with an air flow system for pulling heated air and smoke through the cooking chamber. 
       SUMMARY OF THE INVENTION 
       [0008]    A solid fuel smoker oven incorporating a cooking chamber and a heat source chamber separated by a vertical divider segregating the heat source chamber from the cooking chamber. The heat source chamber includes a self-contained steel firebox with a gas fired burner used to provide heat for cooking as well as to ignite wood or other solid fuel elements used to produce smoke to impart a barbecue flavor to the food. The cooking chamber includes a fan whereby heat and smoke emissions from the firebox are drawn from the heat source chamber into the cooking chamber by a single inlet centrifugal fan. 
         [0009]    The cooking chamber comprises air channels defined by perforated wall panels. The emissions are forced through air channels on each side of the cooking chamber. The air channels have calibrated orifices that vary in size from the top of the channels to the bottom which allow the air flow and temperature inside the cooking chamber to be balanced from top to bottom and side to side. 
         [0010]    In one aspect, the orifice sizes ranges from about 0.75 inch diameter to about 0.375 inch diameter. 
         [0011]    In one aspect, the centrifugal fan functions as a spark arrestor. 
         [0012]    The cooking chamber incorporates a vent tube or flue that extends through the top wall of the oven exposing the cooking chamber to the ambient atmosphere. This vent prevents pressure from building inside the cooking chamber and allows some combustion exhaust to be emitted so proper burner function can be maintained. 
         [0013]    The lower portion of the partition wall separating the cooking chamber form the heat source chamber is open allowing the smoke and heated air to be drawn back into the heat chamber, where the emissions are reheated over the firebox, and recirculated to the cooking chamber via the constant draw of the single inlet centrifugal fan. 
         [0014]    The oven design incorporates multiple rack positions that allow low profile products to be placed closely together and product racks to be spaced further apart for taller/higher profile products. 
         [0015]    The oven is constructed of stainless steel panels that comprise a box-like structure. The four side walls and the top of the oven chambers are composed of inner and outer layers of steel with a thermal insulating material between the two layers of steel. The bottom wall of the oven is constructed of a single wall stainless steel sheet with a drain hole to allow rendered by-product from the cooked product to drain from the cooking chamber into a drain pan. 
         [0016]    In another aspect, the back wall of the oven may be equipped with a second product door into the cooking chamber that allows loading and unloading of product into the cooking chamber from both the front and back sides of the oven. This is commonly referred to as a pass through design. 
         [0017]    Additionally the oven may be equipped with a water reservoir and heating elements mounted to the bottom wall of the oven in the cooking chamber to allow for the production of steam into the cooking chamber during a cook cycle. Access to the heat elements for the steam source is obtained through the access panel located on the lower section of the back wall on the cooking chamber side. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0018]      FIG. 1A  is a front perspective view of an aspect of a smoker oven; 
           [0019]      FIG. 1B  is a rear perspective view of a smoker oven; 
           [0020]      FIG. 2  is a front plan view of a smoker oven with the cooking chamber door open; 
           [0021]      FIG. 3  is a front plan view of the interior of the cabinet; 
           [0022]      FIG. 4  is a front schematic view of the interior of a smoker oven; 
           [0023]      FIG. 5  is a front perspective view of a cooking chamber with an array of racks; 
           [0024]      FIG. 6  is a front perspective view of one side of the cooking chamber illustrating rack supports and perforated wall panels; 
           [0025]      FIG. 7  is a front perspective view of one side of the cooking chamber with the rack supports and a perforated wall panel removed; 
           [0026]      FIG. 8  is a front plan view of a firebox; 
           [0027]      FIG. 9  is a perspective view of the firebox removed from the cabinet; and 
           [0028]      FIG. 10  is a front perspective view of a circulation fan, sans fan shroud. 
       
    
    
     DETAILED DESCRIPTION 
       [0029]    The following is a detailed description of preferred aspects of the present invention including the best mode of carrying out the invention presently known to the inventor. 
         [0030]    One aspect of the oven is indicated generally be reference numeral  20  in the figures. Oven  20  is designed to prepare food products, generally by cooking with heat or flavored smoke or combination thereof. A source of steam, such as a fluid reservoir, or a source of flavored smoke in the cooking chamber may be employed as well. The terms “food products” or “food product” is intended to include commonly prepared meats including, but not limited to, beef, pork, poultry, lamb, wild game, as well as fish or other seafood. The terms “food products” or “food product” also can include vegetables, such as ears of corn, potatoes, onions or any other product that may be prepared by one of heat, steam, flavored smoke, or any combination thereof. In other words, the terms “food products” and “food product” is intended to encompass any items prepared in the oven. 
         [0031]    As shown, oven  20  includes a cabinet  24  having a first side wall  26 , an opposite side wall  28 , a back wall  30 , a top wall  32  and a bottom wall  34 . The cabinet includes a front wall  35  with an opening  36  on one side sealable by an insulated, hinged door  38 . The other side of front wall  35  defines an opening  40  into a firebox  42  adjacent the bottom of the wall. The recited front, back, side and top walls comprise inner and outer layers of steel with a thermal insulating material  43  between the layers. The bottom wall is constructed from single wall stainless steel sheet with the drain hole  44  therein. A collection or drain pan  45  is positioned below the drain hole to collect drippings or waste. The cabinet includes casters  46  under the bottom four corners. 
         [0032]    The recited walls define an interior chamber  47  divided by partition  48  into an internal food preparation or cooking chamber  50  and heat and smoke chamber  52 . The lower part  53  of partition  48  wall is open. 
         [0033]    Heat and smoke chamber  52  is further divided into an upper heat and smoke chamber  54  and firebox  42 . 
         [0034]    In one aspect, door  38  includes a glass front panel that allows observation of food in cooking chamber  50 . As seen in  FIG. 1B , back wall  30  defines wall panel  51  and an opening  56  into cooking chamber  50 . Generally there is a pass through door covering opening  56 . It can be a conventional hinged door or, as shown in the drawing, an optional two door arrangement including an upper insulated, hinged door  58  and a lower insulated, hinged door  59  at opening  56 . The use of two doors allows attention to racks of food at the top or the bottom without having the entire opening  56  exposed. The aspect of oven  20  comprising a front door and back door is referred to as a pass through design which allows loading and unloading for the cooking chamber from the front or back. 
         [0035]    In another aspect, there is an optional steam generating apparatus  60  in cooking chamber  50  on the bottom wall. Steam generating apparatus  60  may comprise a water pan  62  with an internal heat source, such as an electric heating coil or bar type heating elements (not seen) inserted into pan  62  through back wall  30 . There is a drip deflector  64  positioned over pan  62 . 
         [0036]    The interior facades of side walls  26  and  28  of cooking chamber  50  include removable, perforated panels  66 . Panels  66  include a face panel  68  and shorter, end panels  70  positioned at right angles to the face panel. When panel  66  is attached to the interior surface of a side wall, the panel and wall define a heat and smoke channel  72 . Panel  66  defines a plurality of orifices  74 . Orifices  74  are sized and positioned to optimize heat and smoke emissions from channel  72  into cooking chamber  50 . For example, orifices  74  may be positioned such that smoke and heat emitted through the openings are directed toward racks of food product, as will be explained. 
         [0037]    Optimum uniform heat distribution throughout the cooking chamber occurs with orifices  74  at the top of the cooking chamber are larger in diameter than those at the bottom of the cooking chamber. By way of example, in one aspect, heat distribution is optimized by a reduction of orifice diameter of fifty percent (50%) from the top of the cooking chamber to the bottom. In one aspect, an optimum diameter for orifices  74  ranges from about 0.375 inch to about 0.75 inch. More particularly, by way of example, one aspect that performs well provides are orifices  74  at the top of the cooking chamber of about 0.75 inch in diameter that decrease down the vertical height of the perforated panels to about 0.375 inch in diameter at the bottom. In such an embodiment, orifices in between may be of diameters between about 0.75 inch and about 0.375 inch. 
         [0038]    As seen in  FIGS. 5 and 6 , cage-like rack hangers  75  are secured on hooks  76  protruding from the side walls. Rack hangers  75  are positioned over panels  66  and comprise heavy wires  78  extending laterally along the side walls. As seen, any number of racks  80  can be suspended between the rack hangers and in any desired configuration. As best seen in  FIG. 5 , each rack  80  is adjacent a row of orifices  74  such that heat and smoke emitted through orifices  74 , as explained below, are directed across any food products on the rack. In one aspect, smoker over  20  incorporates multiple rack positions that allow low profile products to be placed closely together and product racks to be spaced further apart for taller/higher profile products. 
         [0039]    There is a flue  81  that extends through top wall  32  at a rear corner of the cabinet. Flue  81  allows grease laden vapors, heat and smoke to escape so the cooking chamber does not build up pressure. Flue  81  is constructed and dimensioned so that it does not allow too much heat and air to escape and to help maintain desired temperatures within the cooking chamber. Furthermore, the lower end of flue  81  can terminate near the bottom of the cooking chamber so that it vents the coolest air and also serve as a spark arrestor. 
         [0040]    Heat and smoke chamber  52  is best seen in  FIGS. 3 and 4  and comprises upper heat and smoke chamber  54 , which functions as a plenum and firebox  42 . As seen, the upper end of chamber  54  includes a curved baffle  82 . Baffle  82  is disposed to direct heat and smoke from heat and smoke chamber  52  through duct  84  between cooking chamber  50  and heat and smoke chamber  52 . 
         [0041]    Firebox  42 , illustrated in  FIGS. 8 and 9  is positioned in the lower section of heat and smoke chamber  52 . Firebox  42  generally is constructed from heavy gauge steel and comprises a box  86  and an opening  87  into the box. The opening into box is sealed by an insulated door  88 . Box  86  includes a plurality of openings  89  in the top to allow escape of heat and smoke. As seen in  FIG. 8 , there is a gas jet  90  positioned in the back wall. Solid fuel, such as wood, is placed in box  86  and ignited by gas jet  90 . The burning fuel generates heat to cook the food products in the cooking chamber, as will now be explained. 
         [0042]    As seen in  FIGS. 4 and 10 , there is a convection fan  92  at the top of cooking chamber  50 . In use, fan  92  is covered by a shroud  94 . Fan  92  and shroud  94  are positioned adjacent to, and are in fluid communication with, the outlet of duct  84 . Shroud  94  extends laterally and downwardly over smoke channels  72 . In operation, fan  92  draws heat and smoke from heat and smoke chamber  52 , through duct  84  and down into channels  72 . The heat and smoke egress into the cook chamber through orifices  74  to racks  80  and the food products thereon. All heat and smoke must follow this path into the cooking chamber. Hence, approximately 100% of the heat and smoke generated enters the cooking chamber. 
         [0043]    In one aspect fan  92  operates at about 1700 to about 1800 rpm, more preferably about 1750 rpm and most preferably about 1740 rpm. The fan creates a strong suction from the bottom of cooking chamber  50  through heat and smoke chamber  52  where it is reheated. The velocity by which air flow is circulated and recirculated through smoker over  20  restricts heat and smoke from escaping from cooking chamber  50  when product doors are opened. Hence, the airflow design of smoker oven  20  provides the high heat retention. When the doors are open for loading and unloading of product the recovery time to get the smoker oven back to the cook temperature set point is a fraction of the time required by prior art smoker ovens. 
         [0044]    Moreover, fan  92  and shroud  94  also function as a centrifugal spark arrestor. Any live embers or sparks emitted by firebox  42  are captured in the fan and shroud or are directed downwardly in the cooking chamber such that they are either extinguished or cooled below an ignition point if they escape through flue. 
         [0045]    It will be understood smoker oven  20  can incorporate an appropriate controller to operate and monitor the functions of the oven. Such electronics are generally known to the art. One particularly useful controller is disclosed in U.S. Pat. No. 7,451,691, which is incorporated herein by reference. In operation, the operator can place a desired number of racks  80  in cooking chamber  50 . If the recipe calls for steam, water is added to steam generating apparatus  60 . Food product can be loaded in the cooking chamber from the front or the rear. Smoker oven  20  is programmed for a cooking temperature and cook time appropriate for the specific food product. Solid fuel, such as wood, is loaded in firebox  42  and ignited with a gas flame. As the fuel burns, heat and smoke is generated and rise into plenum  54 . Fan  92  is actuated and draws the heat and smoke through duct  84 . Shroud  94  directs the heat and smoke into channels  72 . The heat and smoke is emitted through orifices  74  toward the racks and food products. The decreasing diameter of orifices  74  from top to bottom provide for optimum heat distribution throughout the cooking chamber. Because the lower portion  53  of partition  48  separating cooking chamber  50  form the heat and smoke chamber  52  is open, it allows the smoke and heated air to be drawn back into the heat and smoke chamber, where the emissions are reheated over the firebox, and recirculated to the cooking chamber via the constant draw of the single inlet centrifugal fan. 
         [0046]    It will be understood that expose elements of the smoker oven, for example, walls, panels  66 , rack hangers  75  and racks  80  are all constructed from stainless steel or other material that is readily cleaned. These elements can be removed from the cabinet and properly cleaned after use. 
         [0047]    It will be appreciated from the foregoing that various changes and modifications may be made in the mobile oven of the present invention without departing from the scope of the invention. Therefore, the foregoing description and accompany figures should be viewed as illustrative only and should not be construed in a limiting sense.