Abstract:
A high efficiency cooking system includes a thermal enclosure having an open mouth at its front, the mouth in communication with the ambient atmosphere, the enclosure having hinged frontal doors below the open mouth, an interior of doors defining an upward air path provided by an air blower for blowing air upwardly through vertical channels within the doors, across the open mouth, into an exhaust assembly above the top of the mouth, and an exhaust assembly for expelling air into the atmosphere. Also included is a horizontal high thermal conductivity panel formed of a stone-like material, positioned on a complemental support, axially journaled on a rigid shaft, rotated by a gear motor. Further included are a pair of hydrocarbon gas or electrical powered infrared OR) emitters.

Description:
BACKGROUND OF INVENTION 
       [0001]    1. Field of Invention 
         [0002]    The instant invention relates to area of ovens for commercial and or large volume cooking, such as restaurant ovens. More particularly, the invention relates to an oven for high efficiency cooking of pizzas or food items at same time. 
         [0003]    2. Description of Prior Art 
         [0004]    There have long been ovens for cooking food items, such as pizzas, in large quantities. A problem with se ovens has been that persons operating same must periodically rotate and reposition items to achieve even and uniform cooking. Also, and even more importantly, has been fact that pizza ovens and like, as known in prior art, require between ten and fifteen minutes to accomplish satisfactory and complete cooking thereof. Accordingly, a restaurant or so-called pizza parlor has been inherently limited in its capacity to furnish completed pizzas to customers by period required for cooking of a pizza therein; resulting in revenue and income of a typical pizza restaurant being more a limitation related to cooking speed of IR ovens than customer base itself. In addition, prior art pizza ovens do not utilize available heat efficiently and, resultantly, significant thermal values escape from door of such prior art units thereby diminishing cooking capacity of oven, and increasing energy demands thereof, increasing cooling requirements for restaurant, and causing undue discomfort. 
         [0005]    The prior art, as is best known to the inventor, is represented by U.S. Pat. No. 5,492,055 (1996) to Nevin, et al, entitled Pizza Oven. Such art however does not combine overhead and underside radiant heating with underside conductive heating through use of a rotating heat reservoir as is set forth herein. 
         [0006]    Various cooking ovens have a permanent front access opening for frequent input and retrieval of food items from access opening. open view of cooking in a restaurant also gains customers&#39; appreciation of genuine food preparation process. However, the heat and exhaust exiting from access opening are undesirable, which elevate surrounding environment temperature and release smoke, dust and smell into surrounding area. Consequently, it is required in the United States that a hood has to be installed in front of access opening of an oven to vent out exhaust exiting from access opening. 
         [0007]    Therefore, it is desirable to have an oven which has a structure or a mechanism to inhibit the heat and exhaust from exiting from access opening. The present invention is also an improvement over the ovens of U.S. Pat. Nos. 6,250,210 and 7,357,131, both of which are incorporated herein in their entirety. 
       SUMMARY OF INVENTION 
       [0008]    A high efficiency cooking system, comprises: (a) a thermal enclosure having an open mouth at front thereof, said mouth in communication with ambient atmosphere, said enclosure having hinged frontal doors below said open mouth, an interior of said doors defining an upward air path therein powered by an air blower beneath said enclosure, blowing air upwardly through vertical channels within said doors and across said open mouth, above said open doors, to a ceiling of said enclosure, and into an exhaust assembly above a top of said enclosure, said exhaust assembly expelling said air into ambient atmosphere; (b) a horizontal high thermal conductivity panel formed of a stone-like material, said panel positioned in a complemental support axially journaled on a rigid shaft, said shaft rotated by a gear motor; (c) a pair of hydrocarbon gas or electrically powered infrared (IR) emitters, one located upon said ceiling of said enclosure and or beneath said panel; and (d) a flicker flame assembly situated at a rear surface of interior of said enclosure and above but proximally to said conductive panel. 
         [0009]    The present inventive system also makes use of heating by convection through the provision of a geometry at a rear or distal region of the oven which, in combination with said infrared element, creates a region of high temperature which is optimal for high efficiency cooking of food types such as pizza. Further integral to the present method, and associated with the use of such a region of high temperature cooking, is the passing, at a rate of 0.5 to 2.5 rpm of the food item into and out of such region to preclude scorching thereof while gaining benefits of taste. Further heating by convection is accomplished by circulating otherwise unused heat, beneath the rotating panel, radially outwardly and then upwardly beyond the periphery of the panel and into the region thereabove. This is further accomplished through internal venting and circulation means within the top of the oven. As such, three forms of heat transfer, namely, conduction, radiation and convection are employed in a balanced fashion in the context of open cavity fluid communication with the atmosphere in order to provide the within objects the advantages thereof, set forth below. 
         [0010]    In another embodiment, the present invention is directed to a method of inhibiting heat and exhaust in an oven from exiting from an access opening thereof. method includes installing instant door panel described above to front of a heating chamber; providing an air supply means near lower end of door panel, and interfacing air supply means with air inlet opening on door panel to provide air supply into a hollow chamber with door panel; and providing an exhaust venting assembly at interior side of door panel, adjacent to an upper end of door panel, wherein exhaust venting assembly pulls air exiting from air outlet slot of mantle into exhaust venting assembly, and forms an air curtain covering access opening at interior side of door panel; wherein air curtain inhibits heat and exhaust inside heating chamber from exiting from access opening. 
         [0011]    It is accordingly an object of present invention to provide an improved system of cooking, having particular application in commercial pizza service establishments, which operates at improved efficiency, providing increased food access, improved taste, and reduces energy consumption for both oven itself and cooling of the ambient work station. 
         [0012]    It is another object to provide a food item cooking oven for cooking of each food item relatively evenly and without need of opening a door or entrance thereof to rotate or reposition food items and wherein efficiency of the oven is not compromised when food items are removed from or repositioned therein. 
         [0013]    It is a further object of the invention to provide a novel system of heating to provide a cooking oven which is reliable and relatively inexpensive to manufacture. 
         [0014]    It is yet a further object to provide a system of cooking which employs a rotating thermal reservoir as a cooking substrate and, in combination therewith, balanced means of conduction heating of the bottom of said panel, heating the top of food items to be cooked, and heating by convection throughout oven, this inclusive of a region of high temperature cooking into which food periodically passes in and out of to thereby obtain benefits of high temperature cooking without risk that food items to be cooked may become scorched or overcooked. 
         [0015]    The above and yet or objects and advantages of present invention will become apparent from hereinafter set forth Brief Description of Drawings, Detailed Description of Invention and Claims appended herewith. 
     
    
     
       BRIEF DESCRIPTION OF THE DRAWINGS 
         [0016]      FIG. 1  is a front perspective view of the inventive high intensity IR oven. 
           [0017]      FIG. 2  is a side cross-sectional view of the oven of  FIG. 1 . 
           [0018]      FIG. 3  is a front view of the IR oven. 
           [0019]      FIG. 4  is a radial cross-sectional view taken along Line  4 - 4  of  FIG. 3 . 
           [0020]      FIG. 5  is a radial cross-sectional view taken along Line  5 - 5  of  FIG. 3 . 
           [0021]      FIG. 6  is a radial cross-sectional view taken along Line  6 - 6  of  FIG. 3 . 
           [0022]      FIG. 7  is a bottom view of the inventive oven. 
       
    
    
     DETAILED DESCRIPTION OF THE INVENTION 
       [0023]    In thermal enclosure  10  (see  FIG. 2 ), a food opening  14  (see also  FIG. 1 ) provides for open cavity fluid communication between the oven interior and atmosphere. As may be noted in  FIG. 2 , oven  14  may, if desired, be mounted upon a plurality of legs  16  which may or may not include swivel wheels  18  thereon. Alternatively, oven  10  may be placed upon any stable surface within the establishment making use thereof. 
         [0024]    With further reference to structure of oven  10 , it may (see  FIG. 2 ) be seen that housing  10  includes an insulative floor  20  and an internal ceiling  22  which slopes upwardly from proximal access opening  14  to a rear surface  24  of oven at a pitch of about five percent, that is, one unit of increase in height for each twenty units of distance from front to back of oven, to define slope of internal ceiling  22 . At left of  FIG. 2  is defined a focused region  26  of high temperature or intense cooking (see also  FIG. 5 ), which is more fully described below. 
         [0025]    A notable feature within the interior of the housing is that of a preferably circular cooking panel  28 , formed of a material for such as calcium aluminate and concrete, which is able to store large quantities of heat and to withstand temperatures of at least 2200 degrees F., although this specific tolerance level is not required for proper oven operation. Panel  28  is therefore formed of a high thermal capacity stone-like material, the measurement of which is about 0.235 BTU/LB/degree. F. or 75,000 BTU&#39;s. 
         [0026]    The panel  28  is rotatably mounted upon a complemental receiver  29  which is mounted upon an axle  30  which includes gear and journal means  32  having a gear motor  34 . As may be noted with reference to  FIG. 2 , heating cooling panel  28  exhibits a diameter relative to diameter of the oven such that an annular area  34  exists between an outer periphery of panel  28  and the inner dimension of the oven  14 . 
         [0027]    As may be seen in FIGS.  2  and  4 - 6 , there are provided upper and lower IR emitters  36  and  38  which are powered by a pressurized hydrocarbon gas (see  FIG. 7 ) through manifold  40 , solenoids  42  and  44 , and conduits  46  and  48  to orifices at the input to the IR emitters  36  and  38  which provide intense thermal radiation above and below cooking panel  28 . The emitters may also be electrically powered. 
         [0028]    At the rear of enclosure  10  is a flicker flame burner  50  (see  FIG. 2 ) which is preferably gas powered through conduit  52  (see  FIG. 7 ) and solenoid  54  which controls the input of pressurized gas from manifold  40 . 
         [0029]    A space  56  beneath panel  28  is relatively small so that minimal heat is spent in this region. Resultingly, most of the energy output of IR emitter  38  is directed to the bottom of panel  28  which, after the oven is started for a given day&#39;s activity, acts to eventually fill the thermal panel to a considerable percent of its thermal capacity. In view of the above, it may be appreciated that by virtue of IR radiation against the lower surface of panel  28 , heat will be stored in the panel and communicated by conduction to the bottom of any pizza or food item upon surface of panel. As such, crust heating occurs from the bottom of the pizza through this process. Because of the substantial thermal capacity of panel  28 , continuous and uniform heating is provided until panel  28  reaches a temperature of about 700 degrees Fahrenheit at which temperature a thermostat causes cycling of the upper emitter  36 . 
         [0030]    Through use of upper infrared radiant (IR) emitter  36 , a temperature of about 1750 degrees F. is applied within the focused region  26  (see  FIG. 2 ) on panel  28  which is the region of intensified heating. While the temperature radiated by emitter  36 , added to that of flicker flame  50 , to pizza crust is substantially higher than the 700 degree F. temperature of panel  28 , the quantity (BTU&#39;s) of heat applied to topping side of the pizza is lower than the quantity of heat applied at bottom of crust side by IR emitter  38 . Such high temperature cooking of the topping of the pizza is highly desirable in accelerating the cooking process without scorching of the topping, this in combination with a continuous slow rotation of panel  28  and its associated pizzas in and out that region  26  of intensified heating. 
         [0031]    It is to be noted that IR emitter  36  may be adjusted to higher or lower energy levels relative to IR emitter  38  to enable cooking of food items other than pizza. Further, solid state ignition, or an entirely solid state IR element may be employed in lieu of the use of perforated ceramic modules or surfaces which emit a gas-air mixture which combusts on a surface of a burner so that heating of ceramic elements causes infrared radiation to be emitted. Other forms of IR heating may be employed. 
         [0032]    It is noted that the interior surface  22  of the heating region of the oven is provided with an entirely black finish as, for example, may be effected through application of a black protective layer to a metallic material of which the housing is formed. Such a black interior surface is important in terms of uniform heating and efficient use of energy. This is achieved through the use of phenomenon known as black body radiation which dictates that an enclosed black surface will absorb more infrared energy relative to the amount of radiation reflected back in the direction from which the radiation was received. This phenomenon increases efficiency of use of radiant IR emitter  36  described above, this by containing energy within the oven interior and not reflecting it out through mouth  12  thereof. 
         [0033]    At the rear of region  26  is provided a flicker flame assembly  50  (see  FIGS. 2 and 5 ) which extends vertically across the rear  24  of the oven interior and serves not only to provide a pleasing wood burning appearance, but also to furnish additional heat within the rear of the oven housing, that is, to region  26  of intensified heating to thereby increase cooking efficiency, through radiation, to the entire system. Flicker flame  50  burns at approximately 1000 degrees F. It is however to be understood that instant inventive system will function, although at a slightly reduced efficiency, without use of the flicker flame assembly. Alternatively to the use of gas as a source of energy for flicker flame  55 , solid state means of intermittently activated phosphorus within an inert gas filled tube or flame-shaped glass envelope may be employed. Either alternative means for the flicker flame may be electrically powered. 
         [0034]    Further to the above, it is to be appreciated that three distinctive forms of heat transfer are employed in present method, i.e., baking of pizza crust by conduction underneath from panel  28 , top and bottom heating by radiation from radiant elements  36  and  38 , and through convection of heat values which are not communicated to panel  28  and which, thereby, pass around lower region  56  thorough annular area  34  of the oven, into the upper cooking region  59  (see  FIG. 4 ) and, therefrom, into region  26  of high temperature heating. The relative intensity of all three of the above forms of heat transfer must be carefully balanced for a particular type of food item to be cooked to obtain optimal results. Such balancing is controlled through the use of a thermostatic probe and/or electrical control of gas inputs  44  of gas quantity to each of the IR infrared heat sources. See  FIG. 7 . 
         [0035]    As above noted, yet additional heating by convection is obtained by regulation of the output of flicker flame  50 . It is noted that through use of region  26  of intensified heating, the otherwise adverse effect of open cavity entrance  12  and its fluid communication with the atmosphere, is overcome. In other words, by providing said region  26  at said distal or rear part  24  of the housing  14 , the effect of the continuously open food access opening  12  is compensated for. Therewith, many benefits of flavor associated with such atmospheric communication cooking as, for example, is described in U.S. Pat. No. 5,560,285 is effected. In addition, through such design, the exterior of the oven housing  12  remains relatively cool, with only two inches of housing insulation. Also, the only heat which necessarily must be exhausted from the system is in connection with flicker flame  50 . Cooking and energy efficiency are thereby maintained, this particularly through control of convected air by means of blower  58  and its input  57 , and therefrom to ducts  66 ,  67 ,  60  and  72  (see  FIG. 7 ), and then to upper region  59 , as is shown in  FIG. 2 . A flue  62  and chimney  63  are provided to exhaust heat from the system, effectively discharging unused combustion gases are effectively removed thru flue  62  and chimney  63 . 
         [0036]    More particularly control of convected air from blower  58  feeds into ducts  66  and  67 , through ports  68  and, into air channels  60  inside of doors  70  (see also  FIG. 7 ), assisting combustion and efficiency of the radiant emitters. An air stream is obtained by collecting excess gases and distributing them in part to radiant emitter  36  and in part to flue  62  to be exhausted. That is, input  57  exerts control over and directs air into blower  58  (see  FIGS. 2 and 7 ) into lower air ducts  66  and  67 , hollow front doors  70  and vertical channel  72  (see also  FIGS. 5 and 6 ). The combined effect of regions  60  and  72  provide an air curtain effect across mouth  12 , below described in greater detail. Before air escapes through proximal opening  14 , flue  62  then divides air by injecting one air stream to radiant emitter  36 . Unused air is then exhausted outside through flue  62  and outer chimney  63 . 
         [0037]    Pieces of wood may be optionally placed near the center of panel  28  to smolder, adding flavor to cooking pizza and food items located outwardly from the axis of rotation. 
         [0038]    With reference to the view of  FIG. 2 , it may be seen that axle  32  is rotated by a shaft sprocket  64  connected to a drive motor  34  through a gearbox by means of a chain  65 . The oven is preferably equipped with control means (not shown) to momentarily stop panel  28  from rotation for ease of introduction or removal of pizza and food items from the oven by a novice. 
         [0039]    Using the above system, one may cook at a temperature of 1000 degrees F. within region  26  because the topping of the pizza is heated by the overhead IR emitter  36 . Additionally, such a high temperature may be employed within region  36  because continuous rotation of the pizza or food item ensures it will only momentarily be exposed to such high heat and, thereby, will not scorch the top thereof. One thereby avoids the well known problem with prior art pizza ovens which requires that the cook reach into the oven to move pizza therein into hotter or cooler spots because of lack of uniform temperature therewithin. Prior art ovens are limited to a 450-500 degree F. internal temperature due to such restrictions. 
         [0040]    Also, as above noted, the lack of any door or permanent closure to oven affords the benefits of atmospheric communication heating above set forth.  FIGS. 1 and 5  indicate that panels  70  may be opened for cleaning and service using hinges  71 . 
         [0041]    Inasmuch as the system is provided with an internal thermostatic probe there is no need to turn the system off during the slow periods during the business day. In terms of construction, housing  14  preferably includes inner and outer walls or shells which are spaced about two inches apart from each other with two one-inch layers of insulation therebetween. The inner shell (interior surface of which is subject to the above-referenced coating) is optionally made of a 12 gauge A36 mild steel, but can be made of or forms of steel and or materials as well. 
         [0042]    Summarizing the thermodynamics of baking a pizza in accordance with the invention, firstly, the crust has to bake; secondly, the cheese has to melt; and thirdly, the toppings need to be heated and amalgamated with the cheese to make the pizza a palatable and pleasant looking and tasting food. In this process, by virtue of fact that panel  28  is very hot, baking of the crust can be accomplished in less than two minutes. To manage the problem of melting cheese and heating toppings, the invention employs infrared energy which is line-of-site specific and, for a very short time, as the pizza on deck rotates through line-of-site, and the pizza passes through intensive heat region  26  and under IR element  36  which causes cheese to melt rapidly and toppings to become heated. Using this method, the time necessary for the cheese and topping integration is less than two minutes. Because this is so quickly accomplished, one obtains the benefit of having a higher panel temperature to thereby bake the crust much quicker than the normal pizza oven which uses a 450 to 500 degree F. panel and ambient temperature within region  26 . This would normally be a restricting factor because at such temperatures the cheese and toppings require twelve to fifteen minutes to become fully cooked and ready for serving. However, with the use of temperatures herein, one achieves an increase in panel temperature to achieve a baking time of the crust of two minutes while simultaneously melting the cheese and cooking toppings, this allowing one to cook product in a much reduced time. In addition, the quality of product, including flavors and tastes of toppings, are much higher than occur from slower cooking conventional pizza ovens. 
         [0043]    In the housing  14 , the high thermal storage capacity food support panel  28 , and other heating means for heating the food support panel  28  have been fully described in U.S. Pat. Nos. 5,560,285, 6,146,677 and 6,250,210 B1, which are herein incorporated by reference in their entirety. Using IR emitters  36  and  38 , the efficiency of fuel gas, typically natural gas, is improved, and waste material from combustion is reduced. The use of electrical energy is also efficient. Therefore, from this aspect, the cooking oven of the present invention is also energy and environmentally more compatible. 
         [0044]    It is noted that the term “oven” used herein denotes a closed heating chamber or heating device with an access opening. The access opening can be a permanent opening without a cover as that shown in  FIG. 1 , however, can also be an opening with a cover such as a door. (see  FIG. 5 ). Although the utility of the air curtain door system of the present invention is illustrated herein in one embodiment, should be understood that the air curtain door system can also be used for an oven or a heating device which has a door covering the front opening. air curtain door system can be installed behind a door of an oven or a heating device. When the door is opened, the air curtain door system can prevent releasing heat, smoke or exhaust waste from the area. In this situation, or the opening of the air curtain door system can be configured to meet the specific structural requirements of the ovens or heating devices. 
         [0045]    An air curtain door system and oven incorporating the air curtain door system of the present invention also have other advantages. Using the instant air curtain door system, the environment temperature in front of the oven is not elevated by the heat released through the mouth  12 . This provides a comfortable working area immediately outside the opening for the workers and also results in a saving of energy required for environmental cooling in the surrounding area. The air curtain door system also provides controlled heat and smoke venting to the outside of a building or exhaust venting assembly. Therefore, it reduces air pollution in the surrounding area of the oven. In fact, a cooking oven equipped with the air curtain door system of the present invention has obtained the permit from Applied Research Laboratory licensed by OSHA, (Miami, Fla.), for use inside restaurants in United States without requiring installation of a hood at front of oven for venting. 
         [0046]    While there has been shown and described above, the preferred embodiment of the instant invention it is to be appreciated that the invention may be embodied otherwise than is herein specifically shown and described and that, within said embodiment, certain changes may be made in form and arrangement of parts without departing from underlying ideas or principles of this invention as set forth in Claims appended herewith.