US20120304978A1

US20120304978A1 - Gas burner secondary air feed

Info

Publication number: US20120304978A1
Application number: US13/517,017
Authority: US
Inventors: Henrique Cesar De Gaspari; Marcos Raphael Da Silva
Original assignee: Whirlpool SA
Current assignee: Whirlpool SA
Priority date: 2009-12-18
Filing date: 2010-12-16
Publication date: 2012-12-06
Also published as: BRPI0914276A2; WO2011072361A3; WO2011072361A2

Abstract

The present invention refers to a gas burner secondary air feed, comprising an air inlet (2) in contact with ambient air; an air exit (3) near the base of flames 9 of a burner (7); an elongated duct (1) connecting said air inlet (2) to said air exit (3), said duct being disposed beneath a cooking table (8) and capable of supplying an air flow from the air inlet (2) towards said air exit (3) by convection generated by flames (9) of the burner (7).

Said duct (1) comprises a straight section (6) substantially parallel to the flat portion of said cooling table (8) and an upward section (5) directed to flames (9) of the burner (7), said straight section (6) connected to the upward section (5) by means of an inflection region (4).

Description

FIELD OF THE INVENTION

The present invention refers to a gas burner secondary air feed for cooking tables.

BACKGROUND

Ovens are widely used home appliances, having a main role in food preparation. Ovens, as known, have the purpose of providing means for heating foods, either by an apparent flame, magnetic induction, heat conduction or any applicable devices. In case of ovens using apparent flame for heating food, some basic features can be found in almost all models of the state of the art.
Generally, said ovens comprise an internal gas pipe coupling a gas reservoir (known as “gas cylinder”) to one or more burners. In most of these products, burners are provided with igniters used for igniting air/gas mixture, thus generating flames which heat a pan bottom or similar utensils. In this case, burners have the function of spreading a flame flow for encompassing the largest portion of a pan surface. Thus, when a user wishes to use an oven or an independent cooking table, he positions a pan or utensil on a tripod (or grid), which is arranged on a burner, handles knobs disposed on an oven interface or on an independent cooking table, which regulate gas flow, and turns on an igniter, when same is present. An igniter actuator can be automatic, when handling gas flow knobs.
Nevertheless, many gas ovens present some drawbacks relative to a flame generated for food heating. Firstly, a total combustion of a gas being flamed may not occur, thus producing high carbon monoxide level released in the air, creating yellowish flame. Such a yellowish flame, as known by a person skilled in the art, covers a pan or utensil inner surface with fouling. Additionally, a second drawback refers to the stability of flames which, without a suitable secondary air feed, may become unstable and thereby self-extinguishing, resulting in gas leakage, when a burner is not equipped with a flame sensing device.
In this sense, secondary air feeding to a burner flame allowing for better stabilizing and obtaining an almost total combustion has been needed. Therefore, it is observed that the state of art brings some exemplary solutions for this problem, as shown below.
DE 19861078 refers to a secondary air feed for gas oven burners. According to the configuration illustrated and described in this EP document, a cooking table comprises openings, beneath which burners are disposed. Since said burners are beneath said cooking table there is an interspace between the burners and cooking table, where said interspace is used as secondary air inlet. However, so as to make air flows to a burner flame, according to the object of this document, a small blower is provided for forcing air towards a flame.
EP 1016823 also refers to a burner provided with an auxiliary air inlet which construction is very similar to that of the device taught by DE 19861078. In this case, openings are also disposed on a cooking table wherein a burner base is arranged at one of these openings, said openings having a diameter larger than that of said burner base so as to form a concentric gap. Said concentric gap is directly associated with an empty space just below said cooling table, this empty space being provided with an air inlet. Said air inlet comprises a small fan for forcing air to circulate in this empty space and towards a burner through an opening made on the cooking table. Air is then supplied upwardly to burner flames.
As can be noted, these two examples of the state of the art employ particularly disadvantageous frames, once a great space under the cooking table is used to provide for a free space so that air can circulate up to the burner flames. Moreover, in both cases air is forced towards said burner flames by means of a fan, thus making such solutions more expensive.
Hence, one may note that there is a need in the state of the art for gas burner secondary air feed of simple structure, which does not occupy a large are beneath a cooking table, in addition to using a smaller number of possible elements wherein the use of fans for forcing air into burner flames is no longer required.

OBJECTS OF THE INVENTION

It is, therefore, an object of this invention to provide a secondary air feed comprising a simple structure and occupying a smaller area beneath a cooking table, in addition to eliminating the use of fans for forcing air into the burner flame.

SUMMARY OF THE INVENTION

The objects of the present invention are accomplished by means of a gas burner secondary air feed, comprising: an air inlet in contact with ambient air, an air exit near a burner flame base, an elongated duct connecting the air inlet with the air exit, which is disposed beneath a cooking table and capable of supplying air flow from the air inlet to the air exit by convection generated by burner flames.

BRIEF DESCRIPTION OF DRAWINGS

Figures show:

FIG. 1—a side cut view of a gas burner secondary air feed;

FIG. 2—a side cut view of a first preferred embodiment of gas burner air secondary feed of the present invention;

FIG. 3—a side cut view of a second preferred embodiment of gas burner secondary air feed of the present invention; and

FIG. 4—a side cut view of a third preferred embodiment of a gas burner secondary air feed of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 of the present invention generally illustrates the preferred embodiments of the present invention, which are shown in more details in FIGS. 2, 3 and 4. As can be seen from FIG. 1, a secondary air feed of the present invention is assembled beneath a cooking table 8 and is designed to be disposed near flames 9 of a gas burner.
In the context of the present invention, a cooking table refers to either a cooking table 8 incorporated into an oven or a separate cooking table, i.e. such as an independent home appliance. Therefore, as used in this specification, the expression “cooking table” should be construed in a broad sense once the present invention can be applied to an oven and also to an independent cooking table.
The secondary air feed of the present invention comprises an air inlet 2 in contact with ambient air. Said air inlet can be in several forms, such as, for example, a rectangular or elliptical shape. Preferably, said air inlet 2 is of rectangular form, contouring the side region design of a cooking table.
In a first preferred embodiment of the present invention, an air inlet 2 is an opening disposed at a cooking table 8, as can be seen from FIG. 2. In this case, said air inlet 2 is a small orifice made on the surface of a cooking table 8, wherein this orifice can be placed in any region of said cooking table 8. Other forms and arrangements of air inlet 2 can be implemented within this embodiment.
In a second preferred embodiment of the present invention, an air inlet 2 is an opening disposed on the front panel 10 of an oven or independent cooking table, as depicted in FIG. 3. Therefore, said air inlet 2 can be made as an orifice on a front panel 10 of an oven or an independent cooking table, with no detrimental to aesthetics of a home appliance. Further, it should be understood that air inlet 2 of this second preferred embodiment may be placed at any region of front panel 10 of an oven or an independent cooking table.
In a third preferred embodiment of the present invention, an air inlet 2 is an opening disposed on the external wall 11 of an oven or an independent cooking table, as seen from FIG. 4. By this way, air inlet 2 can be, for example, an orifice or a hole disposed on a sidewall of an oven or an independent cooking table.
As can be inferred, air inlet 2 does not require a large opening and can be made in the form of a small orifice disposed at any portion of an oven or an independent cooking table, i.e. said air inlet 2 can be placed on any external surface of the oven or the cooking table 8, including, for example: (already mentioned) front panel 10, sidewalls, rear portion, upper surface, among others falling within the scope of the present invention. Furthermore, the present invention provides a variety of arrangements possibilities for said air inlet air 2, so that said inlet 2 does not interfere with aesthetics of the product.
Gas burner secondary air feed of the present invention additionally comprises an air exit 3, as can be seen from FIGS. 1 to 4. Said air exit is designed to be placed near flame base 9 of a burner 7. Preferentially, said air exit 3 is of circular form; however, it is to be understood that the present invention contemplates other possible shapes.
Secondary air burner of the present invention additionally comprises an elongated duct 1 coupling air inlet 2 to air exit 3, allowing for fluids to pass between these areas. Hence, duct 1 has the ability to supply air flow from inlet 2 to exit 2 by convection generated by flames 9 of burner 6. Said duct 1 can also have any cross-section form; however, in the preferred embodiment of the present invention, this duct has a rectangular cross-section form. Depending on where said air inlet 2 and air exit 3 are disposed, duct 1 may have its contour changed, i.e. said duct 1 may have one or more sinuous segments, depending on the place where air inlet 2 is arranged, as can be seen from FIG. 3, where said duct 1 comprises a short curve 12.
As illustrated in figures, duct 1 is disposed just beneath said cooking table 8 so that the thickness of said cooking table which separates said duct 1 from the external ambient is markedly thin.
As can be seen from FIGS. 1 to 4, duct 1 irrespective of the local of air inlet 2 comprises two distinguished sections, i.e., a straight section 6 and an upward section 5. Said straight section 6 is substantially parallel to a flat portion of a cooking table 8 whereas said upward section 5 is directed to flames 9 of burner 7, said straight section 6 being connected to upward section 5 by means of an inflection region 4.
It should be understood that said straight section 6 and upward section 5 can be of any length or contour provided that their inclination characteristics are maintained, i.e., said straight section 5 should be substantially parallel to the flat portion of said cooking table 8, and upward section 5 should be bent in relation to straight section 6 and directed to flames 9 of the burner 7.
By this way, as can be inferred, the present invention does not employ fans or any other means to force air towards flames 9 of said burner 7. Contrarily, the present invention uses natural convection generated by heat produced by flames 9 near the air exit 3, which establishes an air flow inside said duct 1. Therefore, due to the fact that a fan is not used and that natural means for establishing an air flow towards flames 9 are employed, the present invention comprises a significant advantage over the prior art.
Furthermore, it also noted that the present invention is not invasive, in the sense that it occupies small space within a cooking table 8. Consequently, the present invention is of simple structure allowing for easily performing design and installation.
Finally, these advantages result in low costs because fans are not required and the object of the invention is structurally simple.
After describing an example of the preferred embodiment, it should be construed that the scope of the present invention encompasses other possible variations, and is limited by the contents of the appended claims only, including therein possible equivalents.

Claims

1. Gas burner secondary air feed, characterized in that it comprises:

an air inlet (2) in contact with ambient air;

an air exit (3) near the base of flames 9 of a burner (7);

an elongated duct (1) connecting said air inlet (2) to said air exit (3), said duct being disposed beneath a cooking table (8) and capable of supplying an air flow from the air inlet (2) towards said air exit (3) by convection generated by flames (9) of said burner (7).

2. Gas burner secondary air feed, in accordance with claim 1, characterized in that said duct (1) comprises a straight section (6) substantially parallel to the flat portion of said cooling table (8) and an upward section (5) directed to flames (9) of said burner (7), said straight section (6) being connected to the upward section (5) by means of an inflection region (4).

3. Gas burner secondary air feed, in accordance with claim 1, characterized in that said air inlet (2) is an opening provided on the cooking table (8).

4. Gas burner secondary air feed, in accordance with claim 1, characterized in that said air inlet (2) is an opening provided on the front panel of an woven or an independent cooking table,

5. Gas burner secondary air feed, in accordance with claim 1, characterized in that said air inlet (2) is disposed on the external sidewall of an oven or an independent cooking table.