HK1167173A - Gas burner provided with flame propagation channels - Google Patents

Abstract

The atmospheric burner for gas cookers, according to the present invention, comprises two or more substantially concentric flame rings, separated from each other by at least one projecting body of the burner, in which each flame ring is equipped with a plurality of outlet openings to feed a plurality of flames with a gas/primary air fuel mixture. The burner also comprises at least one flame propagation channel obtained in the projecting body between at least two flame rings and it is characterized in that the flame propagation channel(s), with which it is equipped, include at least a diverging or converging portion.

Description

Gas burner with flame propagation channel

Technical Field

The present invention relates to a gas burner (gas burner), preferably for domestic use, of the type comprising at least two flame rings (flamerings) separated from each other by at least one protrusion from the burner, for example comprising a distribution chamber for a fuel mixture, and one or more channels made in the protrusion to spread the flame between the flame rings.

It is to be noted here and below that the term "flame ring" refers substantially, but not exclusively, to an annular element having, on a portion of its outer wall, at least one opening or cut, hole or the like which enables the discharge of the fuel mixture into the external environment to cause its ignition and combustion.

Background

Usually, this element is combined with a distribution chamber for the gas/main air-fuel mixture of the burner to form a so-called flame crown (ring of flames) of the burner. According to known techniques, the flame ring may be made as a separate component or, alternatively, may be made integrally with the body of the burner.

Here and as will be noted below, the term "flame propagation channel" refers to a channel that allows a flame to be transmitted to the mixture exiting from the other flame ring mounted on the burner, once the fuel mixture exiting from one flame ring has ignited, thus causing it to ignite.

Burners of this type are known which are fitted with a plurality of concentric flame rings, usually two, which are provided with one or more distribution channels from one flame ring to the other.

WO2006/046922 describes a gas burner comprising a substantially annular chamber for distributing a fuel mixture in combination with an inner flame ring and an outer flame ring each provided with a fuel mixture outlet opening.

The burner is provided with a spark plug and a thermocouple which, when the burner is mounted on the hob in use, are inside the periphery defined by the annular chamber of the burner, close to at least one opening for discharging the fuel mixture for the inner flame ring.

When the user decides to ignite the burner, the spark plug allows to ignite the fuel mixture discharged from the outlet of the inner flame ring.

As stated, the outer flame ring does not incorporate a spark plug or similar device, the fuel mixture coming out of the opening with which it is equipped being ignited through three channels which allow to establish a connection between the inner flame ring and the outer flame ring ignited by the spark plug or equivalent ignition means. In other words, once the fuel mixture from the inner flame ring is ignited, the distribution channel enables the flame to pass to the outer flame ring, which is then ignited.

According to WO2006/046922, the distribution channels provided to the burner are obtained inside an annular chamber for distributing the fuel mixture associated with the inner and outer flame rings, and said distribution channels are delimited at the top by a cover placed above the annular chamber.

The burner type just described has some drawbacks with respect to the transfer of the flame from the flame crown on the flame ring incorporating the ignition means to the fuel mixture exiting from the flame ring not incorporating these ignition means and separated from the aforesaid flame crown by the annular distribution chamber.

In particular, the applicant has been able to verify that the flame propagation channels of the burners of the prior art do not allow the flame to be effectively "conveyed" through the propagation channels, with the consequent possibility of problems occurring in the correct ignition of the flame ring not equipped with a spark plug or similar associated ignition means.

In fact, with a constant cross section in the distribution channels currently employed (i.e. with a constant section along a plane transverse to the direction of flow of the fluid inside the channel), the flame, or the local flow of the already burnt fuel mixture, cannot be effectively conveyed inside the channel to convey it to another flame ring not equipped with ignition means.

Obviously, if the flame is not transmitted, one or more flame crowns will not ignite, with the problem of local leakage of the non-burning fuel mixture and insufficient thermal energy generated by the burner.

In this case, the user is forced to turn off the burner and make one or more attempts to re-ignite it.

The aim of the present invention is to overcome the above mentioned problems of the currently available burners, in particular to make it possible to obtain a burner equipped with at least two mutually separated flame rings, in which the flame propagation between them occurs in an efficient manner.

Disclosure of Invention

This and other objects are achieved by a gas burner according to the first independent claim and the following dependent claims.

According to the invention, an atmospheric burner for a gas cooker (atmospheric burner) comprises two or more substantially concentric flame rings separated from each other by at least one projecting body of the burner, wherein each flame ring is provided with a plurality of outlet openings for supplying a gas/primary air-fuel mixture for a plurality of flames.

The burner also comprises at least one flame propagation channel obtained in a protrusion located between at least two flame rings, characterized in that: it is equipped with said flame propagation channel comprising at least one diverging or converging portion.

It is to be noted that this particular shape of the flame propagation channels between the burner flame rings results in a change of the pressure and velocity conditions of the combustion mixture passing in these channels, so that the flame can be transmitted between these flame rings in a particularly efficient manner.

More specifically, thanks to the fact that each channel does not have a constant cross section, and therefore has at least one flared or convergent portion, the flames of the ignited flame ring can be effectively "sucked" inside each channel to be conveyed to the other flame rings of the burner.

In particular, the channels provided to the burner according to the invention are able to generate within them a Venturi effect (Venturi effect), which amplifies and stabilizes the effect of "sucking" the flame inside the channels, allowing an efficient transfer of the flame between the rings of flames.

The applicant has been able to verify that the channel equipped with the burner according to the invention is able to effectively convey the flame even in conditions of use in which the burner is at its minimum flow rate.

Furthermore, the burner according to the invention comprises at least one spark plug or equivalent ignition device, functionally (functionally) incorporated into one of the at least two flame rings, while at least one flame ring is devoid of a spark plug or similar device.

The spark plugs ignite the mixture of their associated flame rings, while the fuel mixture exiting the other flame rings without spark plugs is ignited by flame propagation channels that carry the flame from one flame ring to the other.

According to one possible embodiment of the invention, the flame propagation channel between the flame rings provides at least one flared portion, the end of which with the largest cross section is arranged adjacent to or facing the at least one flame ring without spark plugs.

In this way, the flame can be transferred from one flame ring to another in an efficient manner by means of a "suction" effect inside the channel, which effect is obtained due to the particular shape of the cross-section of the flame propagation channel

It is evident that the burner according to the invention allows a reduction in the number of ignition devices, for example spark plugs of the flame ring, while at the same time allowing an efficient and complete ignition of the burner.

It is to be noted that the diverging or converging portion of each flame propagation channel provided for the burner can be defined, for example by inclining the walls of the channel.

According to a preferred embodiment of the invention, the protrusions for separating the flame rings of the burner from each other are distribution chambers for the gas/main air-fuel mixture, and said flame propagation channels are obtained in the distribution chambers.

As is known, the distribution chamber of the gas burner is usually delimited at the top by a cover, in which case the distribution channel can be formed by a recessed channel obtained in the distribution channel, which is closed at the top by the burner cover.

The flame propagation channel may further subdivide the fuel mixture distribution chamber into at least two sections.

According to another possible embodiment, the burner comprises at least one central mixture distribution chamber associated with at least one central flame ring and at least one annular fuel mixture distribution chamber associated with at least one outer flame ring, and the annular chamber in which the flame propagation channel is obtained is externally concentric with the central chamber.

According to the embodiment just described, the spark plug functionally incorporates an outer flame ring of the annular fuel mixture distribution chamber. The central flame ring is ignited by the flame propagation channel, allowing a reduction in the number of spark plugs or ignition devices necessary to fully ignite the burner.

Drawings

Embodiments of the burner according to the invention will now be described, purely by way of non-limiting example and with reference to the accompanying drawings, in which:

FIG. 1 is a plan view of a burner according to the present invention;

FIG. 2 is a cross-sectional view of the burner of FIG. 1 in the plane E-E; and

fig. 3 is a cross-sectional view of the burner of fig. 1 in the plane F-F.

Detailed Description

The atmospheric burner for gas cookers according to the invention is equipped with a main body 1 on which at least two flame rings 2 and 3 are obtained, separated from each other by at least one protrusion of said burner.

As can be seen in the figures, the flame rings 2 and 3 are substantially concentric and, according to a preferred embodiment, the protrusions are distribution chambers for the gas/primary air-fuel mixture.

More specifically, according to a specific aspect of the invention, the burner shown here is equipped with a central distribution chamber 4 associated with the flame ring 2 and a peripheral annular distribution chamber 5 for the fuel mixture associated with the flame ring 3.

In other words, the burner according to the invention preferably comprises two flame rings 2 and 3, the first of which is arranged in a central position and the other of which is arranged in a peripheral position, so as to define two concentric flame crowns.

It is to be noted that each distribution chamber 4 and 5 is at least partially defined by a flame ring, a burner body and a cover (not shown in the figures) having a shape complementary to the upper surface of the opposite flame ring 2 and 3.

In turn, the flame rings 2 and 3 comprise a plurality of openings 15 and 15' for supplying a gas/primary air-fuel mixture to the plurality of flames, which, as is known, form said flame crowns. The fuel mixture discharge openings 15 of the outer flame ring 3 are obtained via a plurality of preferably radial cut-out holes (through cut), which cross over the flame ring 3. Instead, the opening 15' of the central flame ring 2 comprises a plurality of through holes spanning through the flame ring 2.

Obviously, other types and/or forms of openings for discharging the fuel mixture known in the art may be used in the burner according to the invention, without departing from the scope of protection claimed herein.

Moreover, as is known in the art, the flame rings 2 and 3 can be obtained from separate elements which are subsequently mounted on the burner body, or can be made integral with the latter.

It is also to be noted that, even if not explicitly described, and not depicted in the figures, a further flame ring may be obtained inwardly adjacent to the outer annular chamber 5, so as to provide a plurality of fuel mixture outlet openings to generate a further flame crown, which is arranged on the inner side wall of the annular chamber 5, inside the burner, in a position facing the central flame ring 2.

As is known, the burner described here is also equipped with at least one venturi effect mixing chamber 30, in which a gas/primary air-fuel mixture is formed and which feeds the fuel mixture chamber.

In the embodiment shown in the figures, the burner comprises a venturi effect mixing chamber of substantially axial type, which feeds the central distribution chamber 4.

One or more conduits, preferably four radial conduits 9, enable the central distribution chamber 4 to be in fluid connection with the annular distribution chamber 5, so that the gas-entrained air mixture formed can also reach the peripheral flame ring 3 in combination with the annular chamber 5.

Obviously, even though the burner shown here comprises only one venturi effect mixing chamber, it is in fact possible to equip two or more venturi effect mixing chambers for separate and/or combined feeding of the distribution chambers 4 and 5 and of the respective flame rings 2 and 3.

It is also to be noted that the burner according to the invention may be equipped with any known type of venturi effect mixer, including the radial type.

The burner according to the invention also comprises one or more channels 10 for the propagation of the flame between the flame rings 2 and 3.

In particular, these flame propagation channels 10 are obtained in a protrusion or, in the present case, in the outer annular distribution chamber 5, between the two flame rings 2 and 3, and as described in detail below, provided with at least one expansion or convergence.

As will become clear during the description, the particular shape of the flame propagation channels, and in particular the presence of a cross section that varies so as to form at least one divergent and/or convergent portion, allows the flames to be effectively "sucked" inside them, improving their transfer from one flame ring to another.

In particular, as can be seen below, the converging-section (converging-section) of the reduced flared-section shape of these channels 10, or alternatively the simplified shape shown here, built by a section of reduced section followed by a flared section, can advantageously reduce the venturi effect, which generates a low pressure downstream of the reduced section area, which enables an efficient intake of the combustion mixture, i.e. the flame, located close to these channels 10.

In this way, the flame propagation channel 10 enables the flame to pass from one flame ring to another in an efficient manner, preferably during the ignition moment. When the flame ring is ignited by conventional ignition means known in this application, (for example, a spark plug), the flame is conveyed to another flame ring of the burner, which is not equipped with corresponding ignition means.

In fact, the burner according to the invention comprises at least one spark plug, not shown in the drawings, functionally associated with one of the two flame rings, while the other flame ring is devoid of the spark plug or of similar means known in the application.

According to the preferred embodiment shown in the figures, the spark plug is associated with the outer flame ring 3 of the annular chamber 5 and is placed adjacent or close to at least a portion of the discharge opening 15 of the flame ring 3.

According to the prior art, during the ignition moment of the burner, the ignition of the fuel mixture leaving the opening provided close to the spark plug allows the ignition of the fuel mixture leaving the other openings of the flame ring.

As stated, the central flame ring 2 is not equipped with a spark plug or similar device capable of igniting the fuel mixture exiting the openings of said flame ring.

The burner, as shown in the accompanying figures, is preferably equipped with four channels 10 for at least partially distributing the flame obtained in the annular distribution chamber 5.

In more detail, in the embodiment shown here, each channel 10 comprises a recessed channel obtained in the annular mixture distribution chamber 5, the upper opening of which is intended to be covered by a burner cap. The flame propagation channel 10 is then defined, in part, by the annular distribution chamber 5 and the cover (not shown in the figures) mounted thereon, so as to assume a substantially tubular configuration.

Obviously, the distribution channel 10 can be made in alternative ways with respect to the method described above, for example by a conduit passing through the mixture distributor, either above or below, etc., without departing from the scope of protection of the present application.

According to a particular aspect of the invention, the flame propagation channels 10 may also subdivide the distribution chamber 5 into a plurality of portions, preferably four channels radially arranged and evenly spaced from each other, so as to subdivide the distribution chamber into annular distribution chambers of the same size (see fig. 1).

It should be noted that, although reference is made to the embodiment provided with a central flame ring 2 associated with the central mixture distribution chamber 4 and an outer flame ring 3 associated with the annular distribution chamber 5, the distribution channel 10 can be used for any type of burner equipped with any number of flame rings, where it is necessary to transfer the flame from one flame ring to the other, in order to allow the correct and complete ignition of the burner by means of only one or a reduced number of spark plugs.

As stated, the cross section of the channel is not constant (with respect to the direction of flow of the fluid inside it) and is preferably shaped so as to form an expansion, the end of which with the largest cross section is located adjacent to or facing the flame ring without spark plug.

As can be seen from the plan view of fig. 1, the larger end of the flared portion of each flame propagation channel thus faces the central flame ring 2 without spark plugs.

In so doing, when the user intends to ignite the burner and the spark plug, the fuel mixture exiting the openings 15 of the outer flame ring 3, the flame is drawn inside the distribution channel 10 and conveyed to the central flame ring 2, so that the fuel mixture exiting the openings 15' can also be ignited.

Advantageously, the particular shape of the distribution channel, and in particular the presence of at least one flared or convergent portion, allows the flame to be effectively "sucked" in order to be conveyed to the flame ring without the ignition device.

Preferably, the venturi effect is generated inside the distribution channel, which amplifies and stabilizes the suction effect of the flame inside the channel, causing it to be conveyed to the other flame ring.

It is noted that it is possible to create each propagation channel in such a way that it comprises, in the direction of the fluid passage in the channel, at least one convergent portion followed by at least one divergent portion, the largest end of which is placed adjacent to or facing the flame ring to which the flame must be transmitted.

Obviously, the diverging or converging portion of the flame propagation channel with which the burner according to the invention is equipped can be made in different ways. In the embodiment shown in the figures, the distribution channel 10 is equipped with inclined radial walls that cause a change in the cross section of the channel, so as to form at least one expansion.

Claims (14)

1. Atmospheric burner for a gas cooker of the type comprising at least two flame rings (2, 3) substantially concentric and separated from each other by at least one protrusion of the burner, said at least two flame rings comprising at least a plurality of discharge openings (15, 15') for supplying a gas/primary air-fuel mixture to a plurality of flames, and at least one flame propagation channel (10) made in said at least one protrusion located between said at least two flame rings (2, 3), characterized in that: the at least one flame propagation channel (10) comprises at least one divergent or convergent portion.

2. The burner of claim 1, wherein: the at least one distribution channel (10) generates a venturi effect.

3. The burner of claim 1 or 2, wherein: comprising at least one spark plug or other ignition device functionally associated with one of said at least two flame rings (2, 3), at least one of said flame rings (2, 3) not having said at least one spark plug or other ignition device.

4. Burner according to any of the preceding claims, wherein said at least one flame propagation channel (10) between said at least two flame rings (2, 3) is equipped with at least one flared portion.

5. A burner according to claims 3 and 4, wherein the end of said at least one expansion with the largest cross section is arranged adjacent to or facing said at least one flame ring (2, 3) without said at least one spark plug or other ignition means.

6. Burner according to any of the preceding claims, wherein: the at least one protrusion is a gas/main air fuel mixture distribution chamber (4, 5).

7. Burner according to claim 6, wherein said distribution chamber (4, 5) comprises an upper cover, characterized in that: said at least one flame propagation channel (10) comprises a recessed channel made in said distribution chamber (4, 5), said channel being closed at the top by the lid of said at least one distribution chamber.

8. The burner of claim 6 or 7, wherein: the at least one flame propagation channel (10) subdivides the fuel mixture distribution chamber (4, 5) into at least two sections.

9. Burner according to any of the preceding claims, comprising at least one central mixture distribution chamber (4) associated with at least one central flame ring (2) and at least one annular fuel mixture distribution chamber (5) associated with at least one outer flame ring (3), said at least one annular chamber (5) being externally concentric to said at least one central chamber (4), characterized in that: said at least one flame propagation channel (10) is obtained in said at least one annular distribution chamber (5).

10. Burner according to any of the preceding claims, of the type comprising at least one annular fuel mixture distribution chamber (5) associated with an outer flame ring (3) and an inner flame ring, characterized in that: said at least one flame propagation channel is obtained in said at least one annular distribution chamber.

11. Burner according to claim 9 and/or 10, characterized in that: comprising a spark plug functionally associated with said outer flame ring (3) of said at least one annular fuel mixture distribution chamber (5).

12. Burner according to any of the preceding claims, wherein: it comprises at least four flame propagation channels (10).

13. Burner according to any of the preceding claims, wherein said at least two flame rings (2, 3) and said at least one separate protrusion have a circular design and said at least one flame propagation channel (10) has a radial design.

14. The burner of claim 13, wherein: said at least one diverging or converging portion of said at least one flame propagation channel (10) is defined at least by inclined radial walls.