HK1028275A - Electric cooking oven with an ultra-red gas grilling device - Google Patents

Description

Electric cooking stove with infrared gas roaster

The present invention relates to a cooking oven, and more particularly, to a cooking oven having a plurality of operation modes including grill and dry.

Conventional domestic and commercial ovens for cooking food often use multiple cooking modes, such as grilling, roasting, holding, self-cleaning, etc., which typically use gas or electricity as a power source, but not both, although some modern ovens may also use microwaves as a heat source. Electric furnaces have certain well-known advantages over gas furnaces, such as being substantially completely sealed to improve thermal efficiency, while gas furnaces must have fresh air inlets for primary and secondary gases, and an exhaust port for exhausting combustion gases. Gas stoves, in turn, also have certain well-known advantages over electric stoves, such as more uniform heating during grilling. In particular, infrared gas grills can provide extremely uniform and high temperature heating, which is not possible with electric heating elements because of the limited number of heating element rods, the large spacing, and the uneven heat generated.

Accordingly, it is a primary object of the present invention to provide a cooking oven incorporating an infrared gas broiler in an electric heating oven.

It is another object of the present invention to provide a composition combining an infrared gas broiler and an electric furnace, which is completely enclosed except for a flue for introducing a primary gas having a fuel gas for combustion and discharging combustion exhaust gas, whereby a secondary gas does not flow through the furnace to cause a decrease in efficiency.

Other and more detailed objects and advantages of the present invention will become apparent from the following description taken in conjunction with the accompanying drawings, in which:

FIG. 1 is a front view of the furnace of the present invention;

FIG. 2 is a cross-sectional view of the furnace of the present invention taken along line 2-2 of FIG. 1;

FIG. 3 is a partial cross-sectional view of the venturi portion of the furnace of the present invention taken along line 3-3 of FIG. 1;

fig. 4 is a cross-sectional view of the furnace of the present invention taken along line 4-4 of fig. 1.

Referring now to the drawings, a furnace of the present invention, generally designated 10, is shown in the drawings wherein the furnace box is comprised of six insulated enclosed interior walls, namely a top panel 12, a bottom panel 14, a right side wall 16, a left side wall 18, a rear wall 20 and a front wall 22. The front wall 22 has a conventional door 24 which seals tightly in a door opening 25 in the front wall 22 when the door 24 is closed, similar to a conventional electric fire. The top panel 12, bottom panel 14, right side wall 18 and left side wall 18 are completely enclosed and the junctions between all of these walls are also sealed so that no ineffective exchange of air inside and outside the furnace 10 occurs through these walls and junctions. As described below, the rear wall 20 has only those openings required for the operating elements of the furnace 10.

An electrical heating element 26 is provided at the bottom of the interior of the oven 10 to heat the interior of the oven in a conventional manner in a conventional mode of operation, such as preheating, keep warm baking, high temperature cleaning, and the like. The interior of each side wall 16 and 18 has a conventional grate support 28 for supporting a bar grate 30 at any desired height within the oven for supporting a plate 32 and like container of food to be cooked.

A gas broiler, generally indicated by the numeral 34, is located on the upper interior surface of the furnace and is attached to the top plate 12. The gas broiler 34 is preferably of the infrared burner type having a ceramic radiation source 36, three ceramic radiation sources 36 are shown for this size furnace, the ceramic radiation source 36 being a thin ceramic tile-like member having a plurality of small holes 38 extending vertically through the tile, the small holes 38 allowing the mixture of gas and air to pass downwardly through the ceramic radiation source 37 and burn along the bottom surface of the ceramic radiation source 36. The combustion of the gas/air extends substantially along the entire lower surface of the ceramic radiation source 36, thereby heating the ceramic radiation source to 1600 ° F. The heated ceramic radiation sources, in turn, generate red external waves having a peak of about 2.8 microns and radiate downwardly from the ceramic radiation sources 36 in various directions to uniformly heat and cook the food items placed in the plate 32. Upon grilling, the burning of the gas/air mixture along the bottom surface of the ceramic radiation sources 36 is very uniform and continuous, whereby the intensity of the grilling on the food can be adjusted by adjusting the distance of the food from the ceramic radiation sources 36, e.g. by using supports of the grate 30 on the grate support 28 of different heights.

The infrared gas broiler 34 comprises a venturi apparatus, generally designated 40, the venturi apparatus 40 consisting of a cylindrical outer tube 42, a long frusto-conical tube 43, a short frusto-conical tube 44 and a gas nozzle fitting 45. The long frustum-conical tube 43 and the short frustum-conical tube 44 are joined together at their smaller, open ends to form a venturi opening or orifice 46 through which combustion gases are discharged from the gas nozzle fitting 45 through the orifice 46 through a nozzle opening 47 to draw primary gases into the venturi apparatus 40 through a rear opening 48 in the cylindrical tube 42. The venturi apparatus 40 has a substantial length and the long frusto-conical tube 43 preferably has a small angle of inclination, for example about 2 degrees, relative to its sides. According to this design, a substantially stoichiometric mixture of gas and air is generated in the long frustum-conical tube 43, and then the mixture is completely efficiently burned in the combustion that occurs on the bottom surface of the ceramic radiation source 36. The gas may be natural gas, propane, or any other suitable gas at a suitable pressure to produce a desirable gas/air mixture and flow into the gas broiler 34. The combustion gases are provided in a conventional manner through conduit 49.

The gas burner 34 includes a plenum 50 formed by a box formed above and around the ceramic radiation source 36, which also supports the ceramic radiation source 36. The venturi device 40 extends into the air inlet chamber 5 and the cylindrical outer tube 42 seals the opening 52 of the box forming the air chamber 50. An L-shaped baffle 54 is provided at the discharge end 56 of the venturi apparatus 40 to more evenly distribute the gas/air mixture in the plenum 50. Additional baffles may also be provided at appropriate locations in the plenum 50 to enhance the distribution capability of the gas/air mixture at all of the holes 38 of the ceramic radiation sources 36. The venturi apparatus 40 with the fuel gas injected from the gas nozzle fitting 45 creates a positive gas pressure above atmospheric pressure in the plenum 50, thereby forcing the fuel gas/air mixture through the apertures 38 into the ceramic radiation source 36 in a generally uniform manner to create a substantially uniform flame along the bottom surface of the ceramic radiation source 36. The ceramic radiation source is sealed around and to the box with a gasket, such as a ceramic fiber gasket, to ensure that the gas/air mixture flows only through the holes 38.

An igniter 60 is provided directly below one of the ceramic radiation sources 36 to ignite the gas/air mixture. The igniter 60 is preferably a hot surface type igniter having a resistive wire near the bottom surface of the ceramic radiation source 36, although other types of igniters, such as spark igniters, may be used. When the gas broiler 34 is in operation, the resistance wire of the igniter 60 is maintained in a continuous red hot condition to ensure continuous ignition or re-ignition of the gas/air mixture when the flame is not inadvertently extinguished. As shown in FIG. 2, the igniter 60 is preferably spaced laterally from the venturi apparatus 40 to avoid overheating the venturi apparatus.

The operation of the furnace 10 will now be described. The electric heating element 26 and the gas broiler 34 are provided with separate conventional type controls (not shown) so that the gas broiler 34 is turned off when the electric heating element 26 is energized, and conversely, the electric heating element 26 is turned off when the gas broiler 34 is in use. A conventional temperature controller may be connected to the electric heating element 26 to control the temperature throughout the furnace to a desired level during firing or holding. The gas broiler 34 may also be provided with a temperature control to prevent excessive temperatures in the oven, but under normal circumstances the broiling mode will proceed at the highest temperature that the gas broiler 34 can produce until the food is completely broiled. When a grill mode is desired and the controller is properly set, gas from the conduit 49 will be directed through the opening 47 of the gas nozzle fitting 45 into the orifice 46 in the venturi apparatus 40 to draw in fresh air through the opening of the open end 48 of the tube 42 extending through the rear wall 20, and the gas/air mixture is directed by the venturi apparatus 40 into the plenum 50 to create positive pressure to force the gas/air mixture uniformly through all of the apertures 38 of the ceramic radiation sources 36. The controller that activates the gas broiler 34 also activates the igniter 60 to ignite the gas/air mixture that is directed downwardly through the apertures 38 of the ceramic radiation source 36, whereby the combustion raises the temperature of the ceramic radiation source 36 to about 1600 ° F to generate infrared light for grilling. The introduction and combustion of the gas/air mixture through the holes 38 results in the creation of a positive pressure above atmospheric pressure inside the hob. As a result, the combustion gases and heated air rise from the interior of the furnace to the top and are forced through openings 62 in the top of the rear wall 20 into an exhaust duct or stack 64 to the exterior as shown by the arrows in fig. 4. Since no other openings are in communication with the interior of the furnace 10, such as the openings in the floor 14 normally provided in gas fired furnaces for the addition of secondary gases, the positive pressure created by the venturi apparatus 40 and the combustion of the gas/air mixture creates a forced natural draft that causes hot gases to be expelled through the flue 64 because the gas temperature is higher than ambient and the pressure inside the furnace is higher than atmospheric. With this arrangement, combustion exhaust gas is fully effectively exhausted from the furnace during operation of the gas broiler, and the mode of operation of the electric furnace is not compromised by secondary gas continuously passing through the openings in the floor 14 and secondary gas exhausted through the flue 64, as occurs in conventional gas burners using only gas. The ceramic radiation source 36 is also thermally insulated from the plenum 50 to prevent premature combustion of the fuel gas/air in the plenum.

If desired, a conventional convection oven arrangement (generally indicated by the numeral 70) may also be provided for the oven 10 at the rear wall 20. The convection oven assembly 70 includes a fan 71 driven by a motor 72 and is surrounded by a heating element 73, the heating element 73 serving to draw air from the interior of the oven through a wire screen filter 74 mounted in front of a housing 75 and back to the oven from the left and right ends of the housing 75 as shown by arrows C in fig. 2. Normally, the convection oven device 70 is optionally used when the oven is fired with the electric heating element 26 energized, but is also necessary during the cooking of food when the gas broiler 34 is used.

While specific embodiments of the present invention have been described in detail above, it should be understood that various modifications, substitutions, and additions can be made without departing from the spirit and scope of the invention. For example, a particular type of infrared gas broiler 34 is described as having a venturi apparatus 40 mounted in a particular manner, but other types of gas broiler and venturi and mounting means may be used.

Claims (19)

1. A cooking oven, characterized in that it comprises:

a cabinet having an electric heating element installed at the bottom thereof and a gas broiler installed at the top thereof,

the gas broiler has a venturi and a gas nozzle to supply gas from outside the oven and draw air into the venturi to supply a gas/air mixture for combustion,

the flue outlet of the closed oven box, and

the supply of gas/air mixture and combustion of gas/air mixture through the venturi creates positive pressure and elevated temperature in the oven such that combustion exhaust is discharged through the flue outlet.

2. The oven of claim 1 wherein said gas broiler includes a ceramic radiation source having a plurality of holes for passing a gas/air mixture and combustion occurs at the bottom surface of said ceramic radiation source to heat said ceramic radiation source to a sufficient temperature to generate infrared radiation.

3. The oven set forth in claim 2 wherein said gas broiler includes a plenum formed above said ceramic radiation source and said venturi is connected to said plenum to supply a gas/air mixture to and through said plenum to said plurality of holes in said ceramic radiation source.

4. The cooking oven according to claim 3, wherein said venturi creates a positive pressure of the gas/air mixture in said plenum.

5. The cooking oven according to claim 2, wherein an igniter is located adjacent to said bottom surface of said ceramic radiation source, said igniter having a continuously energized resistance wire to maintain combustion of the gas/air mixture during operation of the gas broiler.

6. The oven of claim 1 wherein an igniter is located adjacent the gas broiler and is operable to ignite the gas/air mixture.

7. The cooking oven according to claim 1, wherein said oven chamber is provided with a door at a door opening for selective access, and said door opening, said venturi and said flue opening comprise the only openings from inside said oven chamber to outside said oven chamber.

8. The cooking oven according to any one of claims 1 to 7, wherein the oven comprises a single controller for separately controlling the electric heating element and the gas broiler to perform full oven heating by the electric heating element without grilling and to perform grilling by the gas broiler without performing full oven heating by the electric heating element.

9. A cooking oven, characterized in that it comprises:

a cabinet having an electric heating element mounted at the bottom thereof and a gas broiler mounted at the top thereof,

said gas broiler having a venturi and a gas nozzle for supplying gas from outside said oven chamber and drawing air into said venturi for supplying a gas/air mixture for combustion,

an igniter for igniting the gas/air mixture and having means for continuously maintaining combustion,

a flue outlet at the upper part of the closed oven box,

the venturi, the flue opening and the oven door opening comprise the only opening between the oven box interior and the oven box exterior, and

said supply of gas/air mixture and combustion of said gas/air mixture by said venturi and gas nozzle creates positive pressure and elevated temperature in said enclosed furnace enclosure such that combustion exhaust is discharged through said flue outlet.

10. The cooking oven according to claim 9, wherein the oven includes a single controller for separately controlling the electric heating element and the gas broiler to perform full oven heating by the electric heating element without grilling and to perform grilling by the gas broiler without full oven heating by the electric heating element.

11. The oven of claim 9 wherein the gas broiler comprises a ceramic radiation source having a plurality of holes for passing a gas/air mixture and combustion occurs at the bottom surface of the ceramic radiation source to heat the ceramic radiation source to a temperature sufficient to generate infrared radiation.

12. The oven set forth in claim 11 wherein said gas broiler includes a plenum formed above said ceramic radiation source and said venturi is connected to said plenum to supply a gas/air mixture to and through said plenum to said plurality of holes in said ceramic radiation source.

13. The cooking oven according to claim 12, wherein said venturi creates a positive pressure of the gas/air mixture in said plenum.

14. The cooking oven according to claim 11, wherein said igniter is located adjacent to said bottom surface of said ceramic radiation source, said igniter having a continuously energized resistance wire to maintain combustion of the gas/air mixture during operation of the gas broiler.

15. A cooking oven, characterized in that it comprises:

a closed oven chamber having an insulating and closed top plate, a bottom plate, two side walls, a rear wall and a front wall, and a front door at said front wall,

an electric heating element mounted in said enclosed oven adjacent said floor for full oven heating,

an infrared gas broiler for grilling mounted in said enclosed oven adjacent to said top plate,

the gas broiler has a flame hole opened downward,

the gas broiler has venturi means extending through the rear wall,

said venturi apparatus having a gas nozzle for supplying gas from outside said oven chamber and drawing air into said venturi apparatus from outside said oven chamber to supply a gas/air mixture to said flame ports for combustion,

an igniter adjacent said flame opening for igniting and maintaining combustion of said gas/air mixture,

a flue outlet at an upper portion of the rear wall of the closed oven box,

said supply of gas/air mixture and combustion of said gas/air mixture by said venturi apparatus creates a positive pressure and an elevated temperature in said enclosed furnace enclosure such that combustion exhaust is discharged through said flue outlet, and

a single controller for separately controlling the electric heating element and the gas broiler to perform full oven heating by the electric heating element without barbecuing and to perform barbecuing by the gas broiler without full oven heating by the electric heating element.

16. The oven of claim 15 wherein the gas broiler comprises a ceramic radiation source having a plurality of holes for passing a gas/air mixture and combustion occurs at the bottom surface of the ceramic radiation source to heat the ceramic radiation source to a temperature sufficient to generate infrared radiation.

17. The oven set forth in claim 16 wherein said gas broiler includes a plenum formed above said ceramic radiation source and said venturi is connected to said plenum to supply a gas/air mixture to and through said plenum to said plurality of holes in said ceramic radiation source.

18. The cooking oven according to claim 17, wherein said venturi creates a positive pressure of the gas/air mixture in said plenum.

19. The cooking oven according to claim 16, wherein said igniter is located adjacent to said bottom surface of said ceramic radiation source, said igniter having a continuously energized resistance wire to maintain combustion of the gas/air mixture during operation of the gas broiler.