Abstract:
A roasting oven includes a housing having upper, lower, front, rear, right and left walls defining a cylindrical oven interior. The oven also includes a spit assembly rotatably disposed in the interior, at least one infrared radiation element in the upper wall facing the interior, a water cavity in the lower wall for holding water and drippings, a rotating shaft disposed between the end walls for rotabably supporting the spit assembly, and drive elements coupled to the rotating shaft for turning the shaft during roasting, in which an opening in the front cylinder is provided for inserting and removing meats to be roasted. The infrared element faces the oven interior and enables infrared radiation to be reflected from meat at the interior while curvature of the upper wall of the interior returns heated air which, together with direct radiated heat from the radiation element and the reflected radiation, creates oven temperature in excess of 800° F. at a zone of compressive heating proximal to the upper wall.

Description:
REFERENCE TO RELATED APPLICATION 
     This case is a continuation in part of application Ser. No. 07/882,949, filed May 14, 1992, entitled Roasting Oven, now abandoned. 
    
    
     BACKGROUND OF THE INVENTION 
     1. Field of the Invention 
     This invention relates to an infrared roasting oven and, more particularly, is to an apparatus and process for cooking food items, particularly meats. 
     2. Description of the Prior Art 
     The prior art, as best known to the inventor is represented by U.S. Pat. No. 4,321,857 (1982) to Best, entitled Infrared Gas Grill. The teaching of Best relates to a grill assembly primarily in the nature of a smoking system. Best differs from the instant invention in that it employs a process of open cooking, that is a grill-type system. Best, as a open air system, relies solely upon convection of heat for the cooking process, whereas the present invention, as more fully described below, employs a combination of convection and radiant infrared energy for the effective operation thereof. Accordingly, while Best and the instant invention make certain use of infrared heating, the respective invention otherwise have little relationship to each other. 
     Other prior art known to the inventor include U.S. Pat. No. 4,214,516 (1980) to Friedl entitled Barbecue Oven. The oven of Friedl, which is commercially marketed as the HART ROTISSERIE, does not employ a heat chamber notwithstanding its use in infrared burners therein, nor does it burn wood or any other solid fuel. Further, the system of Friedl exhausts gas and heat out of the top of the cooking cabinet, this in distinction to the herein described inventive structure which employs (as is more fully described below) a compressive high temperature heat chamber at the top of a cylindrical oven. Friedl, employing a square cabinet, is not able to make use of heating zones in the sense of this roasting oven. 
     Other prior art known to the inventor includes U.S. Pat. No. 4,757,756 (1988) to Van Marr, entitled Transportable Outdoor Barbecue Grill. The structure of Van Marr is that of an outdoor barbecue which allows all heat generated therein to escape out of a special purpose flue, thereby obviating the possibility of compressive heating in the sense of my system. 
     Further prior art known to the inventor is U.S. Pat. No. 5,184,540 (1993) to Riccio, entitled Cooking Apparatus With Rotisserie and Reclamation Trap. The teaching thereof is essentially that of an rotisserie oven in which the spit rotates at a greater rate than the drive member thereof. Also, Riccio employs a reclamation trap disposed beneath the spit to recover juices produced during the cooking of food therein. 
     SUMMARY OF THE INVENTION 
     The instant invention constitutes a roasting oven including a housing having respective upper, lower, front and rear walls which, in combination, form a solid right hollow cylinder having a longitudinal axis which, together with right and left end walls, define an oven interior. Said oven further includes a spit assembly rotatably disposed in said cylinder interior, said assembly having an axis of rotation substantially parallel with said longitudinal axis. The inventive oven further includes at least one infrared radiation element in a part of said upper wall facing the interior thereof such that radiation therefrom is reflected from said cylindrical wall toward said oven interior and such that curvature of said upper wall retains hot air which co-acts with heat radiated from said infrared radiation element on said upper wall and with a quantity of said reflected radiation to create temperatures of at least 800° F. in an upper zone of the said upper wall of the oven to thereby effect a nutritious and naturally-tasting cooked product. 
     The roasting oven further includes a flue type conduit communicating with the oven interior at a point below the rear wall of said cylinder and above the longitudinal axis thereof. Included therein is a flue-type fan for discharging air from a portion of said oven interior while allowing the retention of hot air proximal to said upper wall. 
     Further included within the inventive oven is a water cavity in said lower wall for holding water and drippings from the cooked material. The rotating shaft is disposed between said end wails to support said spit assembly. Drive means are coupled to said rotating shaft for returning the shaft to move said spit assembly through the superheated upper wall of said oven interior during roasting. 
     It is, accordingly, an object of the invention to provide a infrared roasting oven which employs reflection of radiant infrared thermal energy to effect a more thorough and natural tasting roasting process. 
     It is another object to furnish a infrared roasting oven, having zones of intermediate and high temperature, which employs both convective and radiant infrared energy. 
     It is further object of the invention to provide an infrared roasting oven of the above set forth type in which the exhaust means thereof selectively withdraws air and heat to effect differential thermal zones. 
     It is a yet further object to provide an infrared roasting oven in which the cooking process is primarily a function of duration of exposure to infrared radiant energy, as opposed to convection heat. 
     A still further object of the invention to provide a infrared roasting oven in which the degree of humidity and circulation of air therein is regulated for purposes of maximizing taste-enhancing smoke from wood burning therein. 
     It is a still further object to provide a roasting oven of the above type which combines the advantages of infrared, flicker flame, and wood cooking methods. The above and yet other objects and advantages of the invention will become apparent with the hereinafter set forth Brief Description of the Drawing, Detailed Description of the Invention, and Claims appended herewith. 
    
    
     BRIEF DESCRIPTION OF THE DRAWINGS 
     FIG. 1 is an elevational front view of the invention; 
     FIG. 2 is right cross-sectional view of the invention seen along the Line 2--2 of FIG. 1; 
     FIG. 3 is an elevational rear side view thereof; 
     FIG. 4 is an elevational side view of the invention showing the index disc and other details; 
     FIG. 5 is a diagrammatic cross-sectional fragmentary view showing an infrared radiation element; 
     FIG. 6 is an elevational end cross-sectional fragmentary view seen along the Line 6--6 of FIG. 5; 
     FIG. 7 is a diagram showing a control chart for cooking several batches of meat in different time segments; 
     FIG. 8 is an end diagrammatic cross-sectional fragmentary detail view along the Line 8--8 of FIG. 1; 
     FIG. 9 is a diagrammatic fragmentary enlarged detail view showing a star-shaped end of a spit with a step-ahead arrangement; 
     FIG. 10 is a diagrammatic perspective view showing the rotating spit assembly; 
     FIG. 11 is a lateral cross-sectional view of the flicker light burner; 
     FIG. 12 is a cross-sectional view seen along the Line 12--12 of FIG. 11, showing the interior construction of the flicker light burner; 
     FIG. 13 is a diagrammatic view showing details of the spit with meat grippers; and 
     FIG. 14 shows an alternate step-ahead arrangement for the spits on the assembly; 
     FIG. 15 is a view of the control panel for the invention system. 
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
     In FIGS. 1, 2, 3 and 4 are shown the main structure of the invention, in which the main body of the oven is advantageously shaped as an elongate cylindrical oven body 1 having an upper side 2, a bottom side 3, a front side 4, a right hand side 6, a left hand side 7 and a rear side 8. 
     A spit assembly 9, (See FIGS. 2 and 10) fills the major part or the interior of the oven body and serves to support meat pieces to be roasted, such as chickens and pork end roasts. The spit assembly 9 is composed of a set of parallel spits 11 on which the meat is skewered. The spit assembly 9 is supported on a rotating shaft 12 that is journalled on bearings in the end sides 6, 7 of the oven body 1. The rotating shaft 12 has, on either end, a sprocket wheel 13 coupled by a chain 14 to a motor M which rotates that spit assembly at some slow speed, e.g., three revolutions per minute. At the very rightmost end, the shaft 12 supports an index disc 17 external to the oven body that rotates with the shaft 12 and has, marked on its perimeter, a number of sectors, equal to the number of spits in the spit assembly, for example, eight spits as shown in FIG. 10. Each sector is aligned with its corresponding spit such that the sector faces forward when the corresponding spit is opposite an opening 11a in the oven body 1. It is to be understood that said opening 11a within the front side 4 of the oven body 1 provides for the insertion and removal of meats to be roasted. However, more importantly, opening 11a provides for a continuously uninterrupted fluid communication between the oven interior and atmosphere. Thereby a process of substantially cold cooking, but for the cooking action within upper zone 26 (more fully described below) is accomplished. The sectors can be marked with, for example, eight different colors, or with numbers or letters or both, so that the operator of the oven can identify meat on each spit or keep apprised of its roasting time by noting the position of respective sectors of the index disc 17 on a control chart (see FIG. 7). 
     One or more infrared radiation elements 18 are installed in the upper side 2 of the oven body 1, which serve to direct infrared radiation into the oven interior, in which such radiation is reflected back and forth between the inner walls so as to fill the interior with reflect infrared radiation creating temperature zones as indicated by dashed lines in FIG. 2 said upper zone 26 comprises a substantially higher temperature area than lower zone 15, as is more fully described below. 
     FIGS. 5 and 6 are structural views of typical infrared radiation elements 18, which include a gas jet for injecting combustible gas into a tubular radiator body 21 of rectangular cross-section. A venturi 22 surrounding the gas jet 19 serves to draw atmospheric air to support combustion of the gas into the elements 18. A fireproof wall 23, facing the interior of the oven in formed of perforated high temperature ceramic material having small flame outlet holes 24 which serve to maintain the fireproof wall 23 at, advantageously, 1700° F. That is, the roasting oven according to the invention includes said infrared radiation elements 18, each formed as said tubular body 21, the gas jet 19 injecting gas at one end of the body. Venturi 22 surrounds the gas jet which supplies air to support combustion of the gas. A slot in the tubular body receives perforated ceramic heater modules for emitting a burning gas-air mixture into the oven interior, wherein the perforated ceramic modules emit infrared radiation into the oven interior. 
     As the meat pieces skewered on the spits 11 rotate with the rotating spit assembly, they are constantly exposed to the infrared radiation from all directions and are cooked to a high degree of tenderness without loss of flavor or moisture. The upper zone 26 of the oven interior (see FIG. 2 and 4) is filled with heated air generally at 850° to 1100° F. which sears and roasts the skin of the meat pieces to a uniform golden color tone which much enhances the looks and flavor of the meat, and helps to retain meat juices. Accordingly, at the upper zone 26, and in the curved region thereof, occurs a compressive heating of trapped superheated air through (1) direct heat rays of the radiation elements and reflected rays from a lens effect of the interior shiny stainless steel at the curved bottom of the oven (2) absorbed energy through the heavy construction of the oven; and (3) produce heat generated by burning gas within the radiant elements. This causes the metal thereof, upon heating, to become itself a radiant, giving-off mild infrared energy. 
     An exhaust flue pipe 37, with an adjustable damper 38, serves to exhaust some air from the roaster interior to the outside via an exhaust fan 39, while drawing in enough fresh dry air to provide circulation and exhaust, without degrading the high temperature of upper zone 26. Fan 39 thereby exhausts humidity from the oven thereby reducing sweating of meat and of spices applied thereto. 
     It is thereby to be appreciated that in a process of cooking meats the inventor has discovered that the best results in regard to tenderness and taste of the roasted meat are attained with the use of infrared heat radiation as opposed to convection heat, this combined with (1) various means for maintaining the right degree of humidity and air circulation inside the cooking chamber, and (2) a controlled degree of the intensity and duration of the infrared radiation. In addition, it has been found that the infrared cooking process can be combined with the injection of taste-enhancing smoke from burning woods into the infrared radiated cooking chamber. Thereby the combination of controlled infrared radiation, reduced humidity, air circulation, and presence of smoke, lead to a superior cooked product. 
     As the spit assembly 9 (see FIG. 10) rotates about the shaft 12, each spit rotates with regard thereto. To this end the spit is rotatable within a pair a aligned holes 29, 31, in two opposite end plates 27, 28, centered on the rotatable shaft 12. In FIG. 9, one end of each spit 11 is shaped like a star 31 with, for example, three arms or spokes 32 that couple with a step-ahead arrangement 34 in the end plate 27 having, for example, four arms 36. As the end plate rotates, the star 31 advances one quarter of a revolution for each turn of the end plate 28, in relation to the end plate 27, and also to the spit assembly 9. In that manner the meat on the spits 11 is constantly rotated in relation to the infrared elements 18, for an even more uniform exposure and browning without overexposure on one side or underexposure on the other side. 
     An alternative step-ahead arrangement for rotating the spit 11 is shown in FIG. 14, wherein the spit 11 turns in a bearing 73 in the spit assembly end plate 27 (see FIG. 10). The end plate exhibits a set of radially extending star spokes 74, e.g. five star spokes. A bumper post 72 is rigidly attached to the oven end plate (see FIG. 14), within reach of the star spokes. As the spit assembly turns in the direction indicated by Arrow A, the spit is turned one increment (e.g. one fifth) of a turn as the bumper post 72 advances the oncoming star spoke 74, turning the spit in relation to the spit assembly 9, as indicated by Arrow B, one increment. A spring element 76 allows another spoke 74 to advance, and prevents the spit 11 from turning back against the spring element 76. 
     A wood chamber 41 (see FIG. 2) is mounted on the back side 8 of the oven body and contains pieces 42 of aromatic wood, such as oak, hickory, mesquite or the like. The wood chamber is forward bonded by a grille 42A of, for example, of expanded metal, so that wood smoke can enter the oven chamber 26 to enhance the flavor of the meat as it cooks An ash chamber 42 below the wood chamber 41 serves to collect burned wood ashes. An ash door 44 provides access to the ash chamber 41 for loading wood in the chamber. 
     A so-called flicker flame including a gas-fed burner 47 (See FIG. 2) is located below the wood chamber 41 and serves to throw a flickering gas light through the grille 42, which illuminates the back of the oven interior and maintains fire in the wood 42 in the wood chamber 41. FIGS. 11 and 12 show respective elevational sectional side views and end views of the flicker flame burner 47 which has a gas inlet 48 for drawing air into the burner, which has a plurality of holes 51 that issue a row of small gas streams 52. Vermiculite granules 49 are located in the path of the gas stream to disperse the gas. 
     In FIG. 8 it may be seen that bottom part of the oven chamber 26 forms a water chamber 53 adapted to contain a pool of water, supplied through a water line 54, with a water cock 56. During cooking meat juices and meat fat collect in the water chamber 53, wherein the fat floats as a layer or a pool of meat juices and water, forming a gravy 62 which can be topped off by pushing down a spring-loaded valve 58, as shown in FIG. 8. By pushing down the valve 58, holes 59 in the valve stem 60 align with holes 61 in the stand pipe 62a so that the gravy 62 can be drawn from a gravy drain hole 63 into a juice pan (FIG. 1). After the gravy is removed, the liquid grease 57 can be drawn off into a grease trap 66 (FIG. 2) and discarded. 
     The spits 11 are advantageously equipped with slidable meat grippers 67, as shown in FIG. 13, having pointed tines 68 that are inserted into the meat 69 and hold it during cooking. Each gripper 67 is secured to the spit 11 by set screws 71. 
     FIG. 7 shows an exemplary cooking schedule 76 with a horizontal axis 73 for marking cooking start and stop times, and a vertical axis, indicating Sectors 1 to 8 of the index wheel 17, each sector indicating a corresponding spit. The chef operating the oven can easily mark on a schedule 76, in the respective time fields 77, the start and stopping time for cooking each batch of meat on a spit corresponding to a sector 74 on the schedule 76. In this manner it is easy for the chef to keep track of all the meat cooking in the oven at all times. 
     The entire oven body 1 may be mounted on legs 72. 
     FIG. 15 shows the control panel for the inventive system. 
     While there has been shown and described the preferred embodiments of the present invention it is to be appreciated that the invention may be embodied otherwise than is herein and specifically illustrated and described and that, within the scope of such embodiment, certain changes may be made within the detail and construction of the parts without departing from the underlying idea of principles of this invention and within the scope of the appended Claims.