Gas burner for grilling food items

Abstract

A gas-fired burner includes a ceramic element within which a gas flow is burned to create heat energy. A portion of the ceramic element surface is covered with a mask to limit the combustion area of the ceramic element and thereby facilitate the maintenance of infrared operation while simultaneously reducing the burner temperature. The burner produces a lower temperature operation without transitioning to the blue flame operation. In other embodiments, novel venturi structures are shown.

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This application claims priority of provisional patent applications entitled HEAT ZONE INTENSIFICATION WITH SURFACE AREA REDUCTION FOR CERAMIC INFRARED BURNERS, INCREASED CROSS-SECTION AIR INJECTING SYSTEM FOR LOW PROFILE INFRARED BURNERS, and IMPROVED VENTURI DESIGNS all filed Mar. 12, 2004 on behalf of Antonio Espinosa Casillas, Applicant of the present

FIELD OF THE INVENTION

This invention relates generally to gas fired burners of the type used in cooking food items and particularly to the efforts at maintaining precision and control as well as improved efficiency of gas burners operating to produce infrared heat for cooking.

BACKGROUND OF THE INVENTION

The use of gas fire burners for cooking food is well known in the art and is well established having been used for many years. While a variety of types of gas fired burners have been developed by practitioners in the art, basically all burners may be considered as operating in either the infrared region of operation or the so-called “blue flame” region of operation. In many respects, infrared heating operation is preferred in that substantially greater heat energy available for cooking is produced. Blue flame operation is correspondingly lower in heat. However, blue flame operation provides substantially greater ease of control for the user. Historically, infrared operation has proven difficult to vary or control in order to produce desired cooking heats at different temperatures such as the higher temperatures used to sear food contrasted with lower temperatures desired to produce long term thourough cooking of food.

Basically the art of grilling or broiling with infrared burners consists of placing the food items which are to be grilled or broiled either above or below a gas fired infrared burner. In the gas fired infrared burners, the burning takes place on the top of the ceramic element or screen surface of the burner assembly. Temperatures exceeding 1600 degrees Farenheit create infrared wavelength energy peaking at 2.8 microns. At such temperature and infrared wave length energy transmission of energy and absorbsion characteristics thereof are maximized. While this type of infrared heat is optimum for high temperature searing of meat or vegetables it is far too intense for final or thourough cooking of food items. Unfortunately, attempts to lower the cooking heat reduces the surface temperature of the burner assembly below the necessary temperature for maintaining infrared wavelengths. As a result, attempts to reduce the temperature of infrared burners typically have the effect of altering their operation to conventional blue flame burner operation. Generally speaking, infrared burners do not operate as blue flame burners. Thus, control of infrared heating burners has proven to be extremely difficult and problematic.

In another portion of a typical burner assembly, a venturi tube is utilized to product a pressure drop in the injected gas which then creates a pressure differential which effectively draws airs through the venturi. This natural aspiration is used extensively in numerous industries and products. Historically, this natural aspiration has been used in both blue flame and infrared burners. For burner assemblies having larger surface areas, large diameters down stream sections of venturi are required. However, this in turn requires undesired structural changes in the burner boxes making them impractical in many operations.

The structure of the venturi tubes utilized in burner assemblies are typically conventional classic venturis having reduced diameter portions within larger diameter tubes. These “necked down” larger tubes produce a reduction of cross sectional area within the travel path of the injected gas. The reduction of area also produces the typical venturi pressure drop which then creates a pressure differential which effectively draws air through the venturi. This natural aspiration is used extensively in numerous industries and burner assemblies in both blue flame and infrared burners.

While the foregoing described prior art burner structures have to some extent improved the art and have in some instances enjoyed commercial success, there remains nonetheless a continuing need in the art for ever more improved, effective and efficient gas burners for applications such as grilling food items.

SUMMARY OF THE INVENTION

Accordingly, it is a general object of the present invention to provide an improved gas burner for grilling food items. It is a more particular object of the present invention to provide an improved gas burner for grilling food items which utilizes improved venturi structures and which facilitates temperature control through a substantial temperature range while maintaining infrared burner operation.

In accordance with the present invention, there is provided an improved infrared burner for grilling or broiling which is operative at lower grilling temperatures while still maintaining infrared operations to allow for final cooking of foods. The invention provides a gas fired burner which maintains sufficient surface temperature on the burner to maintain self cleaning operation and infrared heat production.

In addition, the present invention provides a gas fired burner which utilizes increased diameter venturi suitable for application in low profile burners by providing a non-circular cross-section down stream venturi portion.

The invention also provides for an easier, more cost efficient method for manufacturing a venturi in which the venturi consists of two parts which are tubes of different diameters. The smaller tube is situated within the larger tube such that a venturi effect is created without the conventional “necked down” structure.

BRIEF DESCRIPTION OF THE DRAWINGS

The features of the present invention, which are believed to be novel, are set forth with particularity in the appended claims. The invention, together with further objects and advantages thereof, may best be understood by reference to the following description taken in conjunction with the accompanying drawings, in the several figures of which like reference numerals identify like elements and in which:

FIG. 1 sets forth a top view of a gas fired burner constructed in accordance with the present invention;

FIG. 2 sets forth a top view of an alternate embodiment of the present invention gas fired burner;

FIG. 3 sets forth a top view of an alternate embodiment of the present invention gas fired burner;

FIG. 4 sets forth a top view of a still further alternate embodiment of the present invention gas fired burner;

FIG. 5 sets forth a top view of a still further alternate embodiment of the present invention gas fired burner;

FIG. 6 sets forth a top view of a still further alternate embodiment of the present invention gas fired burner;

FIG. 7 sets forth a top view of a still further alternate embodiment of the present invention gas fired burner;

FIG. 8 sets forth a section view of a gas fired burner constructed in accordance with the present utilizing a venturi having an oval outer portion;

FIG. 9 sets forth a perspective view of the venturi portion of the present invention gas fired burner shown in FIG. 8;

FIG. 10 sets forth a perspective view of a further alternate embodiment of the venturi portion of the present invention gas fired burner;

FIG. 11 sets forth a perspective view of a still further alternate embodiment of the venturi portion of the present invention gas fired burner;

FIG. 12 sets forth a partial section view of a prior art necked down venturi structure for a gas fired burner;

FIG. 13 sets forth a partial section view of a still further alternate embodiment venturi portion of the present invention gas fired burner;

FIG. 14 sets forth a partial section view of a still further alternate embodiment of the venturi portion of the present invention gas fired burner;

FIG. 15 sets forth a side elevation view of a further alternate embodiment of the venture portion of the present invention gas fired burner showing the inner venturi section in dash line.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

FIG. 1 sets forth a top view of a gas fired burner constructed in accordance with the present invention and generally referenced by numeral 10. Burner 10 includes a generally rectangular mask 21 defining elongated rectangular apertures therein. Mask 21 overlies a ceramic burner element 20. A supporting frame 11 secures mask 21 upon ceramic element 20. Frame 11 further supports a gas injection pipe 12. In accordance with the present invention, mask 21 limits the exposed area of ceramic element 20 and thus reduces the temperature of burner assembly 10 while maintaining infrared operation within the burner.

FIGS. 2 through 7 set forth alternate embodiments of the present invention infrared gas fired burner which function in the same manner as burner 10 set forth in FIG. 1. The difference in the embodiments of the present invention burner shown in FIGS. 2 through 7 is found in the varied shapes of the temperature limiting mask used therein. Thus, FIG. 2 shows a gas fired burner 13 having a ceramic element 15 upon which a mask 14 is supported. Mask 14 is substantially the same as mask 21 set forth above and thus operates to limit the temperature of infrared operation.

FIG. 3 sets forth a gas fired burner 16 having a ceramic element 18 upon which a plurality of mask elements 17 are supported. Mask elements 17 cover portions of ceramic element 18 and thus limit temperature of operation for infrared burner 16.

In a similar fashion, gas fired infrared burner 25 supports a ceramic element 27 having a plurality of mask elements 26 thereon while FIG. 5 sets forth a gas fired burner 30 having a ceramic element 32 upon which a plurality of elongated rectangular mask elements 31 are supported. Finally, FIGS. 6 and 7 set forth burners 35 and 40 respectively having ceramic elements 37 and 42 respectively. Burner 35 supports a plurality of square mask elements 36 while burner 40 supports a plurality of mask elements 41 which spell out a written message.

Of importance with respect to the present invention, is the operation of the mask element however shaped to obscure portions of the ceramic elements and thereby reduce temperature of burner operation while maintaining operation in the infrared temperature zone.

FIG. 8 sets forth a section view of a gas fired burner constructed in accordance with the present invention and generally referenced by numeral 45. Burner 45 includes a supporting frame 48 upon which a ceramic element 47 and a mask 46 are supported in the manner described above. Burner 45 further includes an air grill 49 which allows air to move into the burner assembly. Burner 45 further includes a venturi 50 constructed in accordance with an important aspect of the present invention in which an inner tube 51 is partially received within an oval or elliptical outer tube 52. The operation of venture 50 is described below in greater detail. However, suffice it to note here that this variation of venturi structure facilitates a lower profile for the burner overall.

FIG. 9 sets forth a perspective view of a venturi assembly 50 having an oval or elliptical cross-section outer tube 52 and a circular cross-section inner tube 51.

FIG. 10 sets forth a perspective view of a further variation of the novel venturi portion of the present invention burner generally referenced by numeral 55 and having a circular cross-section inner tube 56. Venturi 55 includes a rectangular cross-section outer tube 57.

FIG. 11 sets forth a further variation of the novel venturi assembly of the present invention burner generally referenced by numeral 60. Venturi 60 includes a circular cross-section inner tube 61 and a semi cylindrical or semi elliptical outer cylinder 62.

FIG. 12 sets forth a typical prior art venturi structure in which an outer tube supports an inner tube defining a “necked down” inner venturi tube. The structure of FIG. 12 is typical of prior art venturi's.

FIG. 13 sets forth a partial cross-section view of a gas-fired burner assembly constructed in accordance with the present invention generally referenced by numeral 65. Burner 65 supports a ceramic element 67 having a mask 66 thereon. A venturi 68 constructed in accordance with the present invention includes an outer tube 69 within which an inner tube 70 has been received.

FIG. 14 sets forth a section view of an alternate embodiment of the present invention generally referenced by numeral 75. Burner 75 includes a ceramic element 77 supporting a mask 76. Burner 75 further includes a venture 78 having an outer tube 79 within which an inner tube 80 is partially received.

FIG. 15 sets forth a side view of a venturi constructed in accordance with the present invention and generally referenced by numeral 85. Venturi 85 includes an outer tube 86 and an inner tube 87. Tube 87 has an input reducer to reduce the cross-section area of the venturi.

Of importance with respect to the present invention is the ability of the venturi assembly set forth herein to allow air to move into the gas flow on the outside of the inner tube such as inner tube 70 and 80 shown in venturi's 68 and 78.

While particular embodiments of the invention have been shown and described, it will be obvious to those skilled in the art that changes and modifications may be made without departing from the invention in its broader aspects. Therefore, the aim in the appended claims is to cover all such changes and modifications as fall within the true spirit and scope of the invention.

Claims

1. A gas-fired burner assembly for operation in the infrared range comprising:

a frame;

a gas supply tube for coupling to a supply of gas fuel;

a multi-apertured ceramic element in communication with said gas supply tube for fuel combustion, said ceramic element defining a combustion surface; and

a mask supported upon said combustion surface obscuring some, but not all, of said apertures to limit the operative combustion surface of said ceramic element and reduce the operating temperature of said burner while maintaining infrared operation.

2. The gas-fired burner assembly set forth in claim 1 wherein said gas supply tube includes a venturi having:

an inner tube having a first end receiving gas flow and a second end; and

an outer tube substantially larger in cross-section than said inner tube surrounding said second end.

3. The gas-fired burner assembly set forth in claim 2 wherein said outer tube defines a generally circular cross-section.

4. The gas-fired burner assembly set forth in claim 3 wherein said outer tube defines a non-circular cross-section.