EP1809946A1

EP1809946A1 - Improved gas burner system for food cooking

Info

Publication number: EP1809946A1
Application number: EP05805769A
Authority: EP
Inventors: Walter Falcioni; Tiziano Lacche'
Original assignee: Indesit Co SpA
Current assignee: Whirlpool EMEA SpA
Priority date: 2004-11-12
Filing date: 2005-10-26
Publication date: 2007-07-25
Anticipated expiration: 2025-10-26
Also published as: EP1809946B1; WO2006051368A1; ITTO20040794A1; RU2387923C2; RU2007121661A

Abstract

A gas burner system (1) for food cooking is descrived, comprising a pair of concentric burners , the gas to be supplied to the pair of burners (3, 4) being suitably mixed with air taken above the cooking top (16) on which the burner system (1) is mounted, so as to form an air-gas mixture for the pair of burners, said pair of burners comprising: an outer burner (3) fitted with a first cap (7) having a lower surface and an upper surface and,- an inner burner (4) fitted with a second cap (8) having a lower surface and an upper surface. The lower surface of at least one cap (7, 8) is, in its distal development, substantially inclined upward relative to the bearing plane of said cap (7, 8), so that the flow of air-gas mixture is directed upward, in particular toward apertures (5, 6) for the formation and propagation of the flame.

Description

IMPROVED GAS BURNER SYSTEM FOR FOOD COOKING

DESCRIPTION

The present invention relates to a gas burner system for food cooking according to the preamble of claim 1.

According to the state of the art, burner systems are known which comprise two concentric burners, generally an outer one and an inner one, having a substantially circular shape. The two burners are fed by independent control valves, so that they can be used together or separately in order to achieve good variability and a homogeneous distribution of the heat to be supplied to the cooking containers.

The Patent ITl 232887 in the name of the same Applicant describes a gas burner system comprising two concentric burners in which gas is mixed with primary air above the cooking top on which the burner system is mounted and through ducts operating as a Venturi tube. In order to allow for a uniform outlet of the air-gas mixture through the holes or apertures of the outer burner, wedge-shaped profiles are obtained on the lower surface of the caps covering the outer burners; however, such wedge-shaped profiles have the drawback of requiring caps having a complex construction as well as an excessive and undesired height. The International Patent Application No. WO2004/044490 by Sabaf describes a gas burner system for food cooking comprising a central burner having a first flame crown and at least one outer burner being concentric to the central burner. The air-gas mixture is supplied separately to the burners, in that there is a horizontal chamber providing a radial Venturi effect for mixing primary air and gas. For the purpose of obtaining a uniform outlet of the air-gas mixture through the apertures for the formation and propagation of the flame of the outer burner, it has been thought of using an additional metal element, which is secured to the upper surface of the outer burner by means of screws. In order to improve the outlet of the air-gas mixture through the apertures for the formation and propagation of the flame of the inner burner, another additional metal element is secured to the lower surface of the cap of the central burner. This solution has some drawbacks, too, such as the high number of components making up the entire burner system; this complexity inevitably translates into higher costs. The present invention aims at solving the above-mentioned drawbacks by providing a gas burner system for food cooking having an improved and different construction with respect to any known solutions. In this frame, the main object of the present invention is to provide a gas burner system for food cooking being fitted with economical and effective means allowing for a uniform outlet of the air- gas mixture through the apertures for the formation and propagation of the flame of the concentric burners. Another object of the present invention is to provide a gas burner system for food cooking which offers very good performance by using caps having a simple construction and a reduced height.

Such objects are achieved by the gas burner system for food cooking having the features described in the independent claim 1; advantageous aspects of the present invention are detailed in dependent claims. Further objects, features and advantages of the present invention will become apparent from the following detailed description and annexed drawings, which are supplied by way of non-limiting example, wherein:

Fig. 1 shows an exploded view of the gas burner system according to the present invention;

Fig. 2 shows a sectional view of the gas burner system according to the present invention; Fig. 3 shows a bottom view of the burner system according to the present invention;

Fig. 4 shows a sectional view of the caps of the burner system according to the present invention.

Fig. 1 shows a gas burner system for food cooking, indicated as a whole with reference number 1, comprising a gas supply cup 2 on which an outer burner 3 is placed.

The outer burner 3 consists of two half-crowns 3a and 3b, which are separated from each other by a substantially elliptical space; an inner burner 4 is located within said space and on the cup 2. The outer burner 3 is made up of the two half-crowns 3a and 3b, which are separated from each other in order to ensure a proper supply of secondary air to the inner burner 4.

A pair of spark plugs Cl and C2 and a pair of thermocouples Tl and T2 are located on the cup 2; in particular, according to the embodiment of Fig. 1, the spark plug Cl and the thermocouple Tl are associated with the outer burner 3, whereas the spark plug C2 and the thermocouple T2 are associated with the inner burner 4.

On the outer perimeter of their upper edge, said outer burner 3 and inner burner 4 have main apertures 5 for the outlet and ignition of the gas necessary for forming a flame adapted to heat a cooking container (not illustrated). Reference number 6 indicates secondary apertures being smaller than the main apertures 5 and being preferably located between two main apertures 5; the secondary apertures 6 ensure the propagation of the flame during the ignition of the outer burner 3 and inner burner 4, and allow the flame to stabilize.

A first cap 7 is positioned on top of the outer burner 3, whereas a second cap 8 is positioned on top of the inner burner 4, the shape and dimensions of said caps 7 and 8 almost matching those of said outer burner 3 and inner burner 4. For the purpose of reducing the number of parts making up the gas burner system for food cooking being the subject of the present invention, the first cap 7 is preferably made of one piece and is adapted to be positioned onto the two half-crowns 3a and 3b which make up the outer burner 3. As shown in Fig. 1 and Fig. 2, the cup 2 comprises two outer chambers 9 and 10 as well as an inner chamber 11; two nozzles 12 and 13, being connected to a gas supply duct 14, allow the gas to flow into the outer chambers 9 and 10, respectively. A nozzle 15 is connected to a duct (not illustrated) being independent from the duct 14 and allows the gas to flow into the inner chamber 11.

The gas flowing into the outer chambers 9 and 10 supplies the outer burner 3, whereas the gas flowing into the inner chamber 11 supplies the inner burner 4; the gas supply for the outer burner 3 therefore takes place independently of that for the inner burner 4.

The primary air is taken above a cooking top 16 on which the burner system 1 is mounted, in particular through passages 17 obtained between the cup 2 and the half-crowns 3a and 3b. As shown in Fig. 3, the half-crowns 3a and 3b and the inner burner 4 are connected to one another at the bottom through a channel 18 which runs alongside the passages 17 and ducts 19, 20, 21, which operate as a Venturi tube.

Therefore, the channel 18 allows to channel the primary air entering from the passages 17 and to convey it toward the ducts 19, 20, 21, so that it can be mixed inside said ducts 19, 20, 21 with the gas flowing into the outer chambers 9 and 10 and into the inner chamber 11 of the cup 2. The air-gas mixture is prepared within the ducts 19, 20, 21 and rises therein until it reaches the upper end of said ducts, i.e. the holes 19', 20' and 21 ' (shown in Fig. 1).

Fig. 4 shows a sectional view of the caps 7 and 8. The first cap 7 has an inner edge B abutting on the inner edge of the half-crowns 3a and 3b, and an outer edge Bl being located substantially on the apertures 5 and 6 of the half-crowns 3a and 3b; the second cap 8 has an outer edge B2 being located substantially on the apertures 5 and 6 of the inner burner 4. The first cap 7 has a lower surface 24 and an upper surface 25, whereas the second cap 8 has a lower surface 26 and an upper surface 27. In the following, the expression "distal development" will be used to indicate the direction which develops outward from the axis A of the burner system 1.

As shown in Fig. 4, the lower surface 24 of the first cap 7 is, in its distal development, substantially inclined upward relative to the bearing plane of the first cap 7, i.e. the horizontal plane in this case. In fact, Fig. 4 clearly shows that the inner edge B of the first cap 7 lies in a horizontal plane being lower than the bearing plane of the outer edge B 1.

In Fig. 4, it can also be noticed that both the first cap 7 and the second cap 8 are provided with a central zone having a lower surface being substantially flat and substantially parallel to their bearing plane; said central zone is designated B3 for the first cap 7 and B4 for the second cap 8. Therefore, the lower surface 24, 26 of said caps 7, 8 is not inclined evenly along the entire distal development, though it has large zones being clearly inclined upward; one can then say that the lower surface 24, 26 of the caps 7, 8 is substantially inclined upward for its entire distal development.

Also the lower surface 26 of the second cap 8 is, in its distal development, substantially inclined upward relative to the horizontal or bearing plane of the second cap 8. Said inclination of the lower surfaces 24 and 26 of the caps 7 and 8 allows to direct the flow of air- gas mixture coming from the ducts 19, 20, 21 upward, in particular toward the apertures 5 and 6 of the burners 3 and 4.

In the half-crowns 3a and 3b, in particular at their center and around the holes 19' and 21 ', there are rises 22 and 23 (shown in Fig. 1); said rises 22 and 23 are provided with an inclined surface being complementary to the inclined lower surface 24 of the first cap 7, and cooperate with said first cap 7 for the purpose of directing the air-gas mixture toward the apertures 5 and 6 of the half-crowns 3a and 3b.

Experiments carried out have shown that it is particularly advantageous to manufacture the first cap 7 in such a way that also the lower surface of the outer edge Bl is inclined upward in its distal development, in particular at an angle of inclination α ranging from 4 to 10 degrees relative to the horizontal or bearing plane of the first cap 7.

As regards the second cap 8, too, it has been noticed that it is advantageous to manufacture the lower surface of the outer edge B2 in such a way that it is inclined upward in its distal development; in particular, the optimal angle of inclination of the lower surface of the outer edge B2 corresponds to an angle of inclination β ranging from 6 to 14 degrees relative to the horizontal or bearing plane of the second cap 8. Said angles of inclination α and β of the lower surfaces of the outer edges Bl and B2 allow to direct upward both the flow of air-gas mixture, in particular toward the apertures 5 and 6 of the burners 3 and 4, and the flames, which are properly directed toward a cooking container placed on the burner system.

As to the upper surface 25 of the first cap 7, it can be noticed in Fig. 4 that its inclination corresponds to that of the lower surface 24; as a matter of fact, the upper surface 25 is also, in its distal development, substantially inclined upward relative to the horizontal or bearing plane of said first cap 7.

Said inclination of the upper surface 25 allows to keep the first cap 7, in particular the inner edge B, at an appropriate distance from the apertures 5 and 6 of the inner burner 4, and consequently ensures an adequate operation of both the outer burner 3 and the inner burner 4, while keeping the height of the inner burner 4 low.

The features of the present invention, as well as its advantages, are apparent from the above description. hi particular, the fact that the lower surface of the caps is, in its distal development, substantially inclined upward relative to the horizontal or bearing plane of the cap allows to direct the flow of air-gas mixture upward, in particular toward the apertures for the formation and propagation of the flame.

A further advantage of the present invention is that the lower surfaces of the edges of the caps are so inclined as to allow to direct upward both the flow of air-gas mixture, in particular toward the apertures for the formation and propagation of the flame, and the flames produced by the burners, so as to direct them properly toward a cooking container placed on the burner system.

Besides, the upper surface of the first cap being inclined upward in its distal development allows to keep the inner edge of the first cap at a proper distance from the apertures for the formation and propagation of the flame of the inner burner. A further advantage of the present invention is given by the use of a structure which connects the burners at the bottom; such a structure allows to channel the primary air so that it can be mixed with the gas properly.

A further advantage of the gas burner system for food cooking according to the present invention is given by the fact that the number of components making up said burner system is lower than that required by the prior art; the remarkable advantages offered by this solution are therefore apparent both from an economical point of view and in terms of reliability of the entire burner system.

It is clear that many other variations and applications of the gas burner system for food cooking described herein by way of example are possible for those skilled in the art, as well as that in the practical realization of the invention the components may have shapes and dimensions being different from those described or be replaced with other technically equivalent elements.

Among the various possible modifications, the first cap 7 may be manufactured in two pieces adapted to lie on the half-crowns 3a e 3b.

A further possible modification consists in using a cup for the outer burner 3 and another cup for the inner burner 4.

It can therefore be easily understood that the present invention is not limited to the above-described gas burner system for food cooking, but may be subject to many modifications, improvements or replacements of equivalent parts and elements without departing from the novelty spirit of the inventive idea, as clearly specified in the following claims.

Moreover, the teachings of the present invention may also be applied to a simple gas burner such as, for instance, the inner burner 4 shown in the drawings.

Furthermore, according to a variant which advantageously allows to reduce the costs of the burner system according to the invention, the two burners 3 and 4 may be fed through a single supply being controlled by a single tap.

Said variant may be implemented, for example, by closing the duct (not illustrated) which in the above-described solution of independently fed burners delivers gas into the chamber 11 ; in this case, the nozzle 15 is connected to the duct 14; in this way the gas flows, through the duct 14 and the respective nozzles 12, 13 and 15, both into the outer chambers 17 and 21 and into the inner chamber 11. According to a preferred embodiment, said connection may be obtained by simply drilling said closed duct in the area corresponding to the nozzle 15.

Said latter variant will be immediately recognized by those skilled in the art as a solution which allows to reduce the production costs of the burner system. Compared to the burner system with independent supplies for the two burners 3 and 4, said variant, according to which the burners of the burner system are fed by a common supply, in fact allows to eliminate a control tap, the spark plug Cl and the corresponding thermocouple Tl .

In conclusion, the present invention also relates to a gas cooking top for food comprising at least one burner and/or one burner system having one or more of the above-described features.

Claims

1. Gas burner system (1) for food cooking appliances, comprising a pair of concentric burners (3, 4), the gas to be supplied to the pair of burners (3, 4) being suitably mixed with air taken above the cooking top (16) on which the burner system is mounted (1), so as to form an air-gas mixture for the pair of burners (3, 4), said pair of burners (3, 4) comprising - an outer burner (3) fitted with a first cap (7) having a lower surface (24) and an upper surface (25); an inner burner (4) fitted with a second cap (8) having a lower surface (26) and an upper surface (27); characterized in that the lower surface (24, 26) of at least one cap (7, 8) is, in its distal development, substantially inclined upward relative to the bearing plane of said cap (7, 8), so that the flow of air-gas mixture is directed upward, in particular toward apertures (5, 6) for the formation and propagation of the flame.

2. Gas burner system (1) according to claim 1, characterized in that said first cap (7) has an inner edge (B) lying in a horizontal plane being lower than the bearing plane of an outer edge (B 1 ) of said first cap (7).

3. Gas burner system (1) according to claim 1, characterized in that at least one of said caps (7, 8) is provided with a central zone (B3) having a lower surface being substantially flat and substantially parallel to the bearing plane of said cap (7, 8).

4. Gas burner system (1) according to claim 1, characterized in that at least one of said caps (7, 8) is provided with an outer edge (Bl, B2) whose lower surface is inclined upward in its distal development.

5. Gas burner system (1) according to claim 4, characterized in that said first cap (7) is provided with an outer edge (Bl) whose lower surface is inclined upward in its distal development, in particular at an angle of inclination (α) ranging from 4 to 10 degrees relative to the bearing plane of the first cap (7).

6. Gas burner system (1) according to claim 4, characterized in that said second cap (8) is provided with an outer edge (B2) whose lower surface is inclined upward in its distal development, in particular at an angle of inclination (β) ranging from 6 to 14 degrees relative to the bearing plane of the second cap (8).

7. Gas burner system (1) according to claim 4, characterized in that the inclination of the outer edge (Bl) of said first cap (7) is lower than the inclination of the outer edge (B2) of said second cap (8).

8. Gas burner system (1) according to claim 1, characterized in that said upper surface (25) of the first cap (7) is, in its distal development, substantially inclined upward relative to the bearing plane of said first cap (7).

9. Gas burner system (1) according to the previous claim, characterized in that the inclination of said upper surface (25) of the first cap (7) corresponds to the inclination of the lower surface (24) of the first cap (7).

10. Gas burner system (1) according to claim 1, characterized in that said outer burner (3) comprises two half-crowns (3a, 3b) being separated from each other by a space in order to ensure the necessary supply of secondary air to said inner burner (4) from above the cooking top.

11. Gas burner system (1) according to the previous claim, characterized in that said first cap (7) is made of one piece and is adapted to be positioned onto said half-crowns (3a, 3b).

12. Gas burner system (1) according to claim 10, characterized in that said half-crowns (3a, 3b) comprise rises (22, 23) being provided with an inclined surface being complementary to the inclined lower surface (24) of the first cap (7).

13. Gas burner system (1) according to claim 10, characterized in that said half-crowns (3a, 3b) and said inner burner (4) are connected to one another through a channel (18).

14. Gas burner system (1) according to the previous claim, characterized in that said channel (18) allows to channel the primary air taken above a cooking top (16) through passages (17) obtained between a cup (2) and said half-crowns (3a, 3b).

15. Gas burner system (1) according to the previous claim, characterized in that said channel (18) develops alongside said passages (17) and alongside ducts (19, 20, 21) which operate as a Venturi tube.

16. Gas burner system (1) according to one of the previous claims, wherein said burner system (1) provides an independent gas supply to the two burners (3, 4).

17. Gas burner (4) for food cooking appliances, fitted with a cap (8) having a lower surface (26) and an upper surface (27), the gas to be supplied to the burner (4) being suitably mixed with air so as to form an air-gas mixture; characterized in that said lower surface (26) is, in its distal development, substantially inclined upward relative to the bearing plane of said cap (8), so that the flow of air-gas mixture is directed upward, in particular toward apertures (6) for the formation and propagation of the flame.

18. Gas burner (4) according to claim 17, characterized in that said cap (8) is provided with a central zone (B4) having a lower surface being substantially flat and substantially parallel to the bearing plane of said cap (8).

19. Gas burner (4) according to claim 17, characterized in that said cap (8) is provided with an outer edge (B2) the lower surface of which is inclined upward in its distal development.

20. Gas burner (4) according to claim 17, characterized in that said cap (8) is provided with an outer edge (B2) the lower surface of which is inclined upward in its distal development, in particular at an angle of inclination (β) ranging from 4 to 14 degrees relative to the bearing plane of the cap (8).

21. Gas cooking top (16) for food, characterized in that it comprises at least one burner (4) and/or one burner system (1) according to one or more of the previous claims.