High Efficiency Infra-Red Cooking Oven

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

1. Field of Invention

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.

2. Description of Prior Art

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.

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.

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' 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.

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

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.

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.

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.

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.

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.

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.

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.

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

FIG. 1 is a front perspective view of the inventive high intensity IR oven.

FIG. 2 is a side cross-sectional view of the oven of FIG. 1.

FIG. 3 is a front view of the IR oven.

FIG. 4 is a radial cross-sectional view taken along Line 4-4 of FIG. 3.

FIG. 5 is a radial cross-sectional view taken along Line 5-5 of FIG. 3.

FIG. 6 is a radial cross-sectional view taken along Line 6-6 of FIG. 3.

FIG. 7 is a bottom view of the inventive oven.

DETAILED DESCRIPTION OF THE INVENTION

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.

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.

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's.

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.

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.

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.

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'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.

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'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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

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.

Claims

1. A high efficiency cooking system, comprising:

(a) a thermal enclosure having an open mouth at front thereof, said mouth in communication with the 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 powered infrared (IR) emitters, one located upon said ceiling of said enclosure and or beneath said panel; and

(d) a flicker flame burner situated at a rear surface of interior of said enclosure and above but proximally to said conductive panel.

2. The system as recited in claim 1, further comprising:

a gas manifold having an input of a pressurized hydrocarbon gaseous fuel and output channels directed to inputs to each of said upper and lower IR emitters, said inputs having orifices and an output channel directed to an input to said flicker flame burner.

3. The system as recited in claim 1, in which said ceiling of said enclosure comprises the color black.

4. The system as recited in claim 2, further comprising gas flow solenoids proximally to inputs to each of said IR emitter channels and said flicker flame channel.

5. The system as recited in claim 2, further comprising:

means for adjusting a ratio of gas flow of said upper IR emitter orifice to that of said lower IR emitter orifice.

6. The system as recited in claim 3, in which said ceiling of said enclosure pitches from a higher level at its rear to a lower level as said ceiling approaches said open mouth of the system.

7. The system as recited in claim 6, in which said enclosure defines a substantially circular horizontal cross-section.

8. The system as recited in claim 7, in which a polar extent of said mouth relative to an entire circumference of said enclosure defines a range of between about 90 degrees and about 180 degrees.

9. The system as recited in claim 8, in which a rotational speed of said panel defines a range of about 0.25 to about 2.0 revolutions per minute.

10. The system as recited in claim 9, in which a greatest height of said open mouth defines about 30 percent of an entire height of said thermal enclosure.

11. The system as recited as in claim 10, further comprising:

means for adjusting a ratio of gas flow to said upper IR orifice to that of said lower IR orifice.

12. The system as recited in claim 10, further comprising:

a gas manifold having an input of a pressurized hydrocarbon gaseous fuel and output channels directed to inputs to each of said upper and lower IR emitters, said inputs having orifices and an output channel directed to an input to said flicker flame burner.

13. The system as recited in claim 10, in which said ceiling of said enclosure pitches from a higher level at its rear to a lower level as said ceiling approaches said open mouth of the system.

14. The system as recited in claim 1, in which said infrared emitters are situated proximally to the rear of the ceiling and of the floor respectively of said thermal enclosure.

15. A high efficiency infrared oven for cooking food items. comprising:

(a) a housing having a housing wall including a proximal permanent food access opening for inserting and removing food products to be processed to thereby provide a continuous and uninterrupted fluid communication with ambient atmosphere;

(b) a high thermal storage capacity food product support panel horizontally and rotationally mounted within said housing; and

(c) IR radiant emitters for heating of said support panel for delivering heat above and below said panel to, therefrom, conducively transfer stored heat into food products placed upon said panel, said emitters oriented to deliver heat as the panel rotates to provide a region of intensified cooking, into and out of which food items pass as said food product support panel is rotated.

16. The oven as recited in claim 15, further comprises a flicker flame burner at a rear of an interior of said housing.

17. The oven as recited in claim 16, in which said panel heating means are oriented between an axis of rotation of said support panel and a periphery thereof.

18. The oven as recited in claim 17, further comprising:

means for effecting circulation throughout oven interior thermal values of said IR emitters not transferred to said rotating panel or items therein.

19. The oven as recited in claim 15, further comprising:

thermostatic or control means for balancing temperature and thermal output of said upper and lower IR sources.

20. The oven as recited in claim 18, further comprising:

a black surface comprising an interior of said oven to thereby utilize phenomenon of black body radiation to contain in oven interior radiant energy from said IR heating sources not utilized within said region of intensified heating.