IT202100001640A1 - ATMOSPHERIC GAS BURNER FOR COOKING APPLIANCES. - Google Patents

Description

DESCRIPTION of the invention entitled:

Title: ?Atmospheric gas burner for cooking appliances?

FIELD OF THE INVENTION

The present invention relates to an atmospheric gas burner for cooking appliances, for example and preferably suitable for cooking in domestic environments, of the semi-ventilated type, i.e. of the type in which the combustible mixture, which is supplied by the flame divider or by the - burner flames, ? a combustible mixture usually consisting of a combustible gas, such as methane or LPG, and a certain volume of air (primary) in quantity? not stoichiometric to allow the combustion of the gas, cos? that it is necessary to supply a further volume of atmospheric air (secondary air), present in the surrounding environment in correspondence with the flame holes of the flame divider or burner flame dividers, in order to allow the combustion of the same gas .

PRIOR ART NOTE

In the context of atmospheric gas burners for cooking appliances of the type indicated above, ? prior art to realize a particular type of burner comprising a lower cup, which is constrained to the shelf of the cooking appliance, and an intermediate body which is constrained at the top and in a removable way to the aforementioned lower cup, and which, in turn, comprises a plurality? of delivery chambers for the combustible mixture. The dispensing chambers of the intermediate body are equipped with relative flame-spreaders and are closed at the top by suitable covering means, such as for example lids.

In particular, ? it is known to produce such dispensing chambers of the intermediate body of the burner in a substantially concentric manner, for example by placing a central dispensing chamber at least partially surrounded by one or more? perimeter dispensing chambers, and in which each of them? fed, by means of at least one mixer dedicated to it, for example of the Venturi effect type, with a combustible mixture formed by gas and primary air.

In order to limit the overall dimensions of the burner, and in particular the height dimensions, burners are known in which each mixer of each delivery chamber is a mixer of the so-called ?radial Venturi effect? type, consisting of a short axial duct which ? shaped in such a way as to allow the inflow of a volume of pressurized gas and a suitable volume of primary air to its lower inlet and which ends in a narrow section, beyond which a discoidal chamber opens, shaped in such a way that the fluids which pass through this mixer (ie the combustible gas and the primary air) gradually expand in a radial direction (ie substantially perpendicular to the axis of the duct). When, by means of a special injector, a combustible gas under pressure is injected along the axis of the axial duct, the shape of this mixer allows the generation of a Venturi effect whereby a minimum depression is established at the inlet bottom of the axial duct, which, together with the dragging effect due to the flow of combustible gas under pressure, is sufficient to recall a correct quantity? of primary air within the same axial duct, and for which the correct mixing is obtained, mainly within the aforementioned discoidal chamber, of the fuel gas injected with the primary air so? callback.

The injectors which feed the fuel gas to the respective radial Venturi effect mixers of each dispensing chamber are housed on the lower sump and can be fed separately or jointly.

Although there are burners of the type indicated above with delivery chambers connected to each other by ducts, there are some embodiments of this type of burner in which the delivery chambers can be fluidically separated from each other.

For example, patent WO 2004/044490 A1, in the name of the present Applicant, describes such a burner in which a central combustible mixture delivery chamber ? surrounded by two perimeter dispensing chambers fluidly separated from each other and from the central one, and in which a first radial Venturi effect mixer feeds the central dispensing chamber and two separate radial Venturi effect mixers feed the perimeter dispensing chambers.

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The delivery chambers of the combustible mixture are obtained on an intermediate body of the burner which is bound to a relative lower sump, which houses the injectors of the various radial Venturi effect mixers. The injectors which feed the combustible gas to the radial Venturi effect mixers described in WO 2004/044490 A1 can be adjusted separately or jointly with each other by means of suitable cocks.

WO 2004/044490 A1 does not describe particular shapes of the relative lower cup and furthermore provides that the burner draws primary air through openings located above the shelf of the cooking appliance.

Patent application WO 2011/144630 A2, in the name of DEFENDI, describes another burner of the type indicated above, which is extremely similar to that of WO 2004/044490 A1, although differing from the latter in that the delivery chambers of the combustible mixture, i.e. the central chamber and the two perimetric chambers which at least partly surround the central one, are fluidly connected between of them.

The meeting of combustible mixture flows coming from different radial Venturi effect mixers in the burner of WO 2011/144630 A2 can cause an unbalanced delivery of this mixture from the relative flame-spreaders.

The Chinese patent CN 104696963 A of MIDEA describes yet another burner extremely similar to the one described in WO 2004/044490 A1, in which however ? it is envisaged that the lower sump constrained to the surface of the cooking appliance houses the injectors intended to introduce a gas flow into the relative radial Venturi effect mixers in a single compartment, thus that the primary air recalled by these mixers flows into and affects these injectors at the same time.

The presence of a single housing compartment for the injectors obtained in the lower cup of CN 104696963 A can? lead to an irregular flow of primary air to the individual burner mixers and therefore an irregular formation and distribution of the combustible mixture.

? an object of the present invention is to solve or mitigate the technical problems which afflict known semi-ventilated gas atmospheric burners of the type briefly described above, or in summary those gas burners equipped with more? rooms of

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delivery of the combustible mixture, and intended for cooking appliances.

Another object of the present invention ? therefore that of realizing a burner of the type indicated above which is particularly efficient from a fluid dynamic point of view, allowing a regular supply of the combustible mixture to the relative flame dividers, and which at the same time is simple to manufacture and allows optimal stability. of combustion.

BRIEF SUMMARY OF THE INVENTION

These and other objects are achieved by the atmospheric gas burner for cooking appliances according to the first independent claim. Particular embodiments of this burner are further claimed in the related dependent claims.

The atmospheric gas burner of the semi-ventilated type for a cooking appliance, according to the present invention, comprises a lower cup and means for constraining it to a shelf of the cooking appliance, an intermediate body of the burner constrained and superimposed on this cup lower and having a central chamber for the delivery of the combustible mixture, which ? equipped with its own central flame spreader, and at least one perimetric chamber for the delivery of the combustible mixture, which at least partially surrounds said central chamber and which ? equipped with at least one flame divider at least partially perimeter, as well as? means for the upper covering of said central chamber and of said at least one perimetrical chamber.

The burner according to the invention provides that the aforementioned central chamber and the aforementioned at least one peripheral chamber are fluidically separated, and that each of said delivery chambers comprises at least one of its own radial-type Venturi effect mixer fed by a relative housed injector in the lower cup.

Advantageously, this lower sump comprises, for each of said injectors, a relative housing, each of said housings for said injectors being substantially fluidically separated from each of the other housings, at least when said intermediate body of the burner is? bound to the lower cup.

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The almost complete fluidic separation of the flow of combustible gas and primary air which flows to the flame dividers of the delivery chambers of the burner claimed herein, obtained through the fluidic separation not only of these delivery chambers, but also of the injector housings of the relative radial Venturi effect, allows to optimize the fluid dynamic efficiency of the burner, making the combustion more? regular.

How can the sector expert? understand, the very small pressure differences generated by the radial Venturi effect mixers, in addition to the aforementioned dragging effect due to the injection of a flow of fuel gas, and therefore the fluidic flows produced by them, are easily influenced by variations and turbulence of the? external environment, what? that the achievement of a high fluid dynamic efficiency, as demonstrated in the burner claimed here, is not? discounted and can? lead to a significant improvement in the thermodynamic conditions of combustion.

According to a preferred aspect of the present invention, the intermediate body of the burner can preferably include a combustible mixture delivery chamber which? equipped with its own central flame-spreader, and two perimetric chambers for the delivery of the combustible mixture, for example substantially semi-annular in shape, which at least partially surround said central chamber and in which each of them is? equipped with at least one perimeter flame divider. The two perimeter chambers and the central chamber are fluidically separated from each other and consequently each of them comprises at least its own radial Venturi effect mixer.

This configuration optimizes the fluid flows of the gas and primary air, as well as of the combustible mixture obtained from their mixing, and therefore improves the fluid dynamic conditions in which the burner operates.

Furthermore, given that the burner claimed here can? provide not only a single organ for regulating the fuel gas injectors, for example a single tap which simultaneously controls the flow of gas to the injectors, but alternatively also the presence of two or more? organs of regulation of the injectors, for example a cock for each injector, so? to check so

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once the flow of gas to the various injectors and therefore the flow rate of the mixture in the individual delivery chambers is differentiated, the preferred solution described here allows to control the distribution of heat on the surface of the burner in an extremely accurate manner.

In a further embodiment of the present invention, the holes of each flame-spreader are shaped to horizontally direct the outgoing combustible mixture, for example by arranging the outflow section of the combustible mixture so that the relative walls are substantially vertical and develop along a substantially horizontal axis, when the intermediate body of the burner is? bound above to the aforementioned lower cup. This solution, in combination with the solution which sees for each combustible mixture delivery chamber its own path substantially separated fluidically from the others and the solution which consists in the use of various radial Venturi effect mixers, leads to an improvement in the effectiveness of the burner in terms of flame propagation and therefore of the heat supplied. The substantially horizontal outflow of the combustible mixture from the flame holes of the flame spreaders reduces any pressure drops to which the mixture flow can be subject and therefore, remembering that the use of pi? radial Venturi effect mixers involves the fact that they ? given the dimensional limitations of the burner? do not have high flow rates, a better uniformit? of the distribution of the flames on each flame divider.

According to yet another aspect of the present invention, what will it look like? clear to the expert in the field, the burner object of this invention can? indifferently, provide means for allowing the primary air to be fed into the radial Venturi effect mixers either by withdrawing the primary air from above the shelf of the cooking appliance, or alternatively (or hypothetically also jointly) by withdrawing the primary air from above under this shelf of the cooking appliance.

Finally, how will it be? clear to the person skilled in the art, the means for covering the delivery chambers of the combustible mixture of the burner claimed here can be individual for each delivery chamber or in a single piece to cover two or more?

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dispensing chambers simultaneously.

BRIEF DESCRIPTION OF THE ATTACHED FIGURES

These and other aspects of the present invention will be even more clear to the person skilled in the art from the description of an embodiment of the present invention, provided here by way of non-limiting example, with reference to the attached figures, in which:

figure 1 ? a perspective view of a burner according to a first embodiment of the invention;

figure 2 ? a sectional view, along the line A-A, of the burner of figure 1; figure 3 ? a sectional view, along the line B-B, of the burner of figure 1; figure 4 ? a three-dimensional view of the lower cup of figure 1;

figure 5 ? a three-dimensional view of the flame-spreader of the burner of figure 1;

figure 6 ? a three-dimensional view of the lids of the burner of figure 1; figure 7 ? a perspective view of a burner according to a second embodiment of the invention;

the figure 8 ? a sectional view, along the line A-A, of the burner of figure 7; and figure 9 ? a sectional view, along line B-B, of the burner of Figure 7. DETAILED DESCRIPTION OF SOME EMBODIMENTS OF THE PRESENT INVENTION

With reference initially to Figure 1, an atmospheric gas burner 10 for a shelf of a cooking appliance, according to a first embodiment of the present invention, comprises a lower cup 1, shaped to be fixed to a shelf 4 of a cooking appliance. cooking, an intermediate body 2 of the burner 10, equipped with dispensing chambers and a plurality? of divider-flames and shaped to couple in a removable way to the lower cup 1, as well as? means for the upper cover of the intermediate body 2, specifically consisting of two covers 3a, 3b.

According to one aspect of the present invention, the lower cup 1 of the burner 10 is made in a single piece, cos? as ? the intermediate body 2 is made in one piece, while the covering means, ie the two lids 3a, 3b, are made in two separate pieces. Other modes? construction of the burner can however be envisaged without departing from the scope of protection required here. Examining more in detail the burner 10, with reference in particular to figures 2, 3 and 4, this comprises, as mentioned, a lower sump 1, preferably constituted by a single generally concave body, which in turn comprises, in addition to means for its connection (not shown) to the shelf 4 of a cooking appliance, a duct 7, generally horizontal, which is equipped with a connection to a pipe of an external gas distribution network (on the right in figure 2) and with three outflow openings which in turn are fluidically connected to three injectors 6a, 6b, 6c, respectively fixed on the bottom of three housings 5a, 5b, 5c made in this lower cup 1 of the burner 10.

The feed pipe 7 of the fuel gas to the injectors 6a, 6b, 6c ? functionally connected, according to one aspect of the present invention, to a single valve which simultaneously regulates the gas flow directed to these injectors 6a, 6b, 6c.

It should be noted that although in the embodiment of the burner 10 illustrated herein ? Is there only one feed duct of the fuel gas injectors 6a, 6b, 6c, so? that a single tap regulates the flow of gas directed simultaneously to the injectors 6a, 6b, 6c, alternative embodiments of the burner 10 are naturally possible, in which each injector 6a, 6b, 6c ? powered by its own gas supply pipe, regulated by a corresponding tap, so? that the flow of gas directed to each injector can? be regulated independently from the other flow rates, or still in which there is a first duct, with a relative regulating cock, which regulates the gas flow to the central injector 6b and a second duct, with a further relative regulating cock , which regulates the gas flow simultaneously to the two lateral injectors 6a, 6b, or other combinations of these solutions.

The lower cup 1, in the particular embodiment of the invention examined here, is shaped in such a way as to define the aforementioned housings 5a, 5b, 5c substantially fluidically separated from each other (in particular when the burner 10 is assembled or at least when the intermediate body 2 is coupled to the lower sump 1) and to have inlet openings for the primary air A which open, when the lower cup 1 is fixed to this shelf 4, above the shelf 4 of the cooking appliance and which are fluidically connected to these housings 5a, 5b, 5c of the injectors 6a, 6b, 6c.

As the person skilled in the art will well understand, these inflow openings for the primary air can be made in such a way that they are arranged below the shelf 4 when the lower cup 1 is placed. fixed to this shelf 4, or they can be partially arranged above and partially arranged below this shelf 4 of the cooking appliance.

In any case it should be noted that the openings for the inflow of primary air obtained thanks to the particular shape of the lower cup 1, are shaped in such a way that, preferably, for each of the housings 5a, 5b, 5c of the injectors 6a, 6b, 6c there is at least one inflow opening that ? distinct from the inflow openings for the other housings. In this way, each housing 5a, 5b, 5c of the injectors 6a, 6b, 6c is fed by its own flow of primary air A which is taken in thanks to at least one opening for the primary air.

On the lower sump 1, as can be seen in particular in figure 4, there are also arranged a safety thermocouple 11 and a spark plug 12 which, when the burner 10 is on? completely assembled, are adjacent to the flame holes of at least one flame divider of the intermediate body 2 of the burner 10.

In the embodiment of the burner 10 shown in Figure 1, the thermocouple 11 and the spark plug 12 are arranged close to each other. of the central flame divider of the intermediate body 2 of the burner 10.

The lower cup 1, with reference also to figure 5, is otherwise? shaped in such a way as to couple at the top, in a removable way, with the intermediate body 2 of the burner 10, which in turn? shaped in such a way that, once coupled to the lower cup 1, it separates the housings 5a, 5b, 5c of the same lower cup 1 from each other, thus that they are fluidically separated from each other, with the exception of the aforementioned inflow openings for the primary air A, which naturally fluidly connect all the housings 5a, 5b, 5c to the external environment above and/or to the below shelf 4 of the cooking appliance.

The intermediate body 2 of the burner 10, more? in particular, it comprises a central chamber 9b for dispensing the combustible mixture and two perimetric chambers 9a, 9c for dispensing the mixture which, shaped in a semi-annular form, surround said central chamber 9b.

Each of the central and peripheral delivery chambers 9b, 9a and 9c of the intermediate body 2 ? fluidically separated from the other dispensing chambers and ? equipped with its own flame divider from which the combustible mixture flows.

Note that with the term ?sparti-flamme? here we mean a wall which at least partially surrounds a delivery chamber of the combustible mixture and which ? equipped with holes, called flame holes, designed to allow the outflow of this combustible mixture for its combustion. In the embodiments of the burner according to the present invention shown here, these flame holes of the flame spreaders are made as slits in at least parts of the walls surrounding the relative combustible mixture delivery chamber, which take the form of a through hole , or of a flame hole, thanks to the means for covering the intermediate body of the burner itself, which thus define the upper wall of these openings.

Other configurations of these openings, for example obtained entirely, such as perforations, in parts of a wall surrounding a combustible mixture delivery chamber, are equally possible.

How will you see? better hereinafter, the holes of the flame-spreaders of the burners shown here preferably have a shape such as to direct the outgoing combustible mixture flow along a substantially horizontal direction. The central and peripheral chambers 9b, 9a, 9c for delivering the combustible mixture of the intermediate body 2 of the burner 10, when the intermediate body 2 is? connected above the lower cup 1, are located respectively in correspondence with the housings 5b, 5a and 5c of the lower cup 1 and communicate fluidly with these housings 5b, 5a, 5c thanks to the respective radial Venturi effect mixers 8b, 8a, 8c of which ? equipped with the intermediate body 2, extending respectively within the aforementioned housings 5b, 5a, 5c.

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Pi? in detail, each of the combustible mixture delivery chambers 9a, 9b, 9c comprises at least its own radial Venturi effect mixer 8a, 8b, 8c which is designed to form and feed the combustible mixture, consisting of gas and primary air, to the relative delivery chamber 9a, 9b, 9c and which is in turn fed by a relative injector 6a, 6b, 6c arranged in its own housing 5a, 5b , 5c of the lower sump 1 and by a flow of primary air recalled by the same radial Venturi effect mixer 8a, 8b, 8c.

Remember that with the expression ?primary air? does it mean that volume of atmospheric air which is mixed with a combustible gas, such as methane or city gas, in a proportion lower than the stoichiometric one necessary to allow the combustion of the mixture so? obtained. In this way, the combustible mixture made up of gas and primary air requires the addition of a further volume of atmospheric air, called ?secondary air? it can be burned. The secondary air, in the burners for cooking appliances, is usually consists of atmospheric air present in the vicinity? of the flame holes from which the combustible mixture emerges and from which the combustion flames depart, once this combustion is triggered for example by a spark plug. Both the primary air and the secondary air, in common burners for cooking appliances, are not normally fed through forced flows and therefore do not require ventilation appliances for their flow into the burner.

Do you also remember? than a ?mixer with radial Venturi effect? Not ? other than a duct or duct comprising in succession a preferably converging section, a narrow section, and a diverging section, in which the preferably converging section is? made up of a cylindrical tube with a preferably decreasing diameter, the narrow section? a section, or a section, of an annular duct with a constant area which ? coaxial to the preferably convergent section, and the divergent section? consisting of a discoidal chamber which extends radially from the narrow section, developing along surfaces substantially orthogonal to the axis of the preferably converging section and of the narrow section. When a gas flow, via an injector, is introduced into the preferably converging section according to a direction coinciding with that of the axis of the same

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preferably converging section, the conformation of this radial Venturi effect mixer, as known, generates a depression, in correspondence with the inlet section of the preferably converging section, which draws primary air, and also it causes, substantially in correspondence with the radial divergent section, where an expansion takes place with relative recovery of the pressure of the fluids passing through it, the mixing of the primary air with the injected gas.

At this point, we wish to point out that even if here yes ? described a burner 10 comprising an intermediate body 2 which defines three dispensing chambers 9a, 9b, 9c with relative three radial Venturi effect mixers 8a, 8b, 8c and a relative lower sump 1 with three housings 5a, 5b, 5c for three injectors 6a, 6b, 6c, we want to underline here that also burners comprising an intermediate body with a central delivery chamber and a single perimetric delivery chamber, fluidically separated from the central chamber, and therefore a corresponding lower sump with only two housings for two relative injectors, falls within the scope of protection requested here.

Even burners with four or more? fluidically separated dispensing chambers obtained on the intermediate body and corresponding four or more? housings for the injectors obtained on the lower sump fall within the scope of protection requested here. Going back to the burner 10 of figures from 1 to 6, how would the person skilled in the art have? already appreciated, when the intermediate body 2 ? connected at the top, albeit in a removable way, to the lower sump 1, three regions are generated within the burner 10 which are substantially separated from each other fluidically (with the exception of their fluidic communication with the external environment due to the inflow of primary air) and which are constituted by the dispensing chambers 9a, 9b, 9c of the intermediate body and by the respective housings 5a, 5b, 5c of the lower cup 2, overlapping each other. These separate regions communicate with the external environment, above or below the shelf 4 of the cooking appliance, through relative openings for the primary air inlet A and each contain an injector 6a, 6b, 6c, and a relative mixer 8a, 8b, 8c with radial Venturi effect.

Each of the mixers 8a, 8b, 8c, of these separate regions, as can be seen for example in figures 2, 3 and 5, comprises a lower cylindrical section with axial development with

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decreasing diameter, whose inlet section is crossed by the gas injected by the relative injector 6a, 6b, 6c and by the primary air recalled by the same mixer 8a, 8b, 8c due to the Venturi effect, a narrow section located at the top? of this lower cylindrical section, followed by a disc-shaped expansion chamber, with radial development, defined below by an annular flat surface 13a, 13b, 13c (figure 5) and above by the corresponding surface, facing this annular flat surface 13a, 13b, 13c, covering means constituted, in the burner 10 shown here, by covers 3a, 3b.

The delivery chambers 9a, 9b, 9c of the burner 10 within which the combustible mixture formed in the relative mixers 8a, 8b, 8c diffuses are respectively equipped with flame spreaders extending along at least one of their perimeter walls, and in particular as regards the perimeter chambers 9a, 9c, these flame-spreaders preferably extend along the outer perimeter walls, so to allow the outflow of this combustible mixture towards the outside and the propagation of the flames in substantially circular rings.

Other embodiments in which the perimetric chambers 9a, 9c for delivering the combustible mixture also comprise a flame-spreader along their inner perimetric wall are obviously possible.

It should be noted that between the peripheral dispensing chambers 9a, 9c which substantially surround the central dispensing chamber 9b, there are channels 16a, 16b which separate these peripheral chambers 9a, 9c and which allow both a flow of secondary air towards the center of the burner 10, and possibly the propagation of the flame from the inside to the outside of the burner 10, or vice versa.

It should be noted that the aforementioned separation of the internal space of the burner 10 into three substantially fluidically separated regions, constituted by the union of the dispensing chambers 9a, 9b, 9c of the intermediate body 2 with the relative housings 5a, 5b, 5c of the lower cup 1 of the burner 10, makes it more? adjust the mixing of the gas with the primary air in the radial Venturi effect mixers 8a, 8b, 8c, makes it more? homogenizes the flow of the combustible mixture within the three delivery chambers 9a, 9b, 9c of the combustible mixture itself, as well as preventing any turbulence, or other adverse thermodynamic or physical conditions, affecting one of the regions of the burner 10 from influencing the other regions , with a consequent increase in the stability? of combustion.

In particular, this solution which sees the creation of three substantially fluidically separated regions, allows to calibrate in an optimal way the same injectors 106a, 106b, 106c, so to allow, in the design phase, an accurate balancing of the distribution of the power supplied by the burner, also thanks to the different pressures potentially present in these separate regions.

In fact, these substantially fluidically separated regions of the burner 10 define three respective burners, largely separated from each other.

According to a preferred aspect of the present invention, the flame dividers of the burner 10 comprise flame holes, defined in this specific case by slits 14 and 15 closed at the top by the aforementioned covers 3a, 3b of the burner 10, which are shaped in such a way to direct the flow of the combustible mixture effluent from said flame holes along a substantially horizontal direction, ie substantially parallel to the bottom of the relative dispensing chamber and therefore substantially parallel to the cooking surface 4.

For example, the outflow section of the combustible mixture of these flame holes, defined at least in part by the slits 14, 15 (respectively intended to create actual flame holes and pilot flame holes), can be made in such a way that the relative walls are substantially vertical and develop along a substantially horizontal axis, when the intermediate body 2 of the burner 10 is bound above to the aforementioned lower cup 1 of the same burner 10.

This shape of the flame holes prevents undesired load losses during the delivery of the combustible mixture to the external environment and therefore helps to increase the stability of the flame. of combustion, as well as allowing an optimal arrangement of the flames coming out of the flame divider. As above already? mentioned above, the burner 10 illustrated in figures 1 to 6 comprises, as upper closure means of the intermediate body 2, two lids 3a, 3b, respectively intended to cover the top of the two peripheral chambers 9a, 9c for supplying the fuel gas of the intermediate body 2 and the central chamber 9b

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supply of fuel gas, of the same intermediate body 2.

This solution makes it possible to make the central combustible mixture delivery chamber 9b in such a way that it extends in height in a different way from the height extension of the two perimetric combustible mixture delivery chambers 9a, 9c, which can thus have a height lower or higher than that of the aforementioned central chamber 9b.

Such a possibility? Not ? provided in the atmospheric gas burner 110 shown in Figures 7 to 9 which, for the rest entirely similar to the burner 10 shown in Figures 1 to 6, provides that the covering means of the intermediate body 102 consist of a single cover 103 , with substantially planar development.

The burner 110, substantially identical to the burner 10 described above, comprises, in addition to the lid 103 and the intermediate body 102, a lower sump 101 comprising three housings 105a, 105b, 105c for respective three fuel gas injectors 106a, 106b, 106c and a gas supply duct 107 from an external distribution network to the aforementioned three injectors 106a, 106b, 106c.

The intermediate body 102 comprises three delivery chambers of the combustible mixture 109a, 109b, 109c, fluidically separated from each other and equipped with relative flame-spreaders, which each comprise a relative radial Venturi effect mixer 108a, 108b, 108c and which are intended to to couple, when the burner 110 ? assembled, and then the intermediate cup 102 ? connected at the top, albeit in a removable way, to the lower cup 101, respectively with the housings 105a, 105b, 105c of the same lower cup 101, so to be defined regions (chambers) substantially separated from each other fluidically and each equipped with at least one inflow opening for the primary air A, with at least one injector 106a, 106b, 106c and with at least one relative mixer with radial Venturi effect 108a, 108b , 108c.

In this way, each of these regions in fact behaves like a separate burner from the others, even if the control of the fuel gas flow directed to the injectors 106a, 106b and 106c is, in the embodiment illustrated here, achieved by a single cock which determines the flow rate of the gas within said supply duct 107.

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However, it should be noted that, also in this burner 110, each of the injectors 106a, 106b, 106c of the lower sump 101 can alternatively be fed by a flow of fuel gas regulated individually by a relative tap, so? that the lower cup 101 includes more? fuel gas supply ducts to these injectors 106a, 106b, 106c.

In any case, the separation of the burner 110 into three regions which in fact constitute three burners substantially fluidically separated from each other allows the same injectors 106a, 106b, 106c to be calibrated in an optimal way and therefore allows balancing in an extremely accurate way the distribution of the power delivered by the burner, and in particular the distribution of the maximum thermal power on the bottom of the cooking container placed on this burner, thanks to the fact that the pressures in these regions do not equalize each other.

Do you also observe? that even if the primary air inflow openings A are made in the burner 110 above the shelf 104 of the cooking appliance, it? of course it is possible to make these openings, in whole or in part, below this shelf 104.

Furthermore, the housings 105a, 105b, 105c of the lower cup 101 turn out to be, when the intermediate body 102 ? in engagement with this lower cup 101, substantially isolated from each other fluidly, so that the injection of the gas and the inflow of primary air A into the respective radial Venturi effect mixers 108a, 108b, 108c is not? influenced, or ? very little influenced, by the physical (thermodynamic) conditions which occur in the other housings of the lower sump 102 of the burner 110.

Similarly, the separation of the dispensing chambers 109a, 109b, 109c from the intermediate body 102 prevents any adverse thermodynamic conditions which may possibly affect one of the dispensing chambers from having an effect on the other dispensing chambers.

This conformation of the burner 110, like that of the burner 10, therefore increases the stability? of combustion.

The stability? of the combustion of the burner 110 ? increased otherwise? from the shape of the flame holes of the flame dividers of which ? endowed the body

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intermediate 102, which are shaped in such a way as to direct the outgoing combustible mixture along a substantially horizontal axis.

Again, how will it be? clear to the skilled in the art, the fact that the covering means of the intermediate body 102 consist of a single cover 103 with planar development, while imposing that the heights of the walls of the central and perimetric dispensing chambers 109a, 109b, 109c be the same, simplifies the production of said covering means with obvious manufacturing savings.

Furthermore, it can be observed that in the burner 110, unlike the burner 10 of figures 1-6, moreover, the spark plug ? placed externally to the external ring of flames of the burner, while the safety thermocouple ? placed in correspondence with the flame spreader of the central chamber 109b for delivering the combustible mixture, how can it be done? appreciate from the representation of figure 7. This indicates that the arrangement of the spark plug and the safety thermocouple ? linked to design criteria and does not reveal the scope of protection of this patent. Finally, it should be noted that, although two embodiments of an atmospheric gas burner according to preferred aspects of the present invention have been shown here, with geometric shapes and configurations schematically shown in the figures, any other atmospheric gas burner which provides the solution claimed here, regardless of its geometric shape, its dimensions and the materials with which it is made? completed, however falls within the scope of protection defined here.

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Claims (10)

1. Atmospheric gas burner (10; 110) of the semi-ventilated type for a cooking appliance, comprising a lower pan (1; 101) and means for fastening it to a shelf (4; 104) of the cooking appliance , an intermediate body (2; 102) constrained and superimposed on said lower sump (1; 101) and having a central chamber (9b; 109b) for delivering the combustible mixture which is? equipped with its own central flame divider, and at least one perimetric chamber (9a; 9c; 109a; 109c) for delivering the combustible mixture, which at least partially surrounds said central chamber (9b; 109b) and which? equipped with at least one perimeter flame divider, as well as? means (3a, 3b; 103) for the upper covering of said central chamber (9b; 109b) and of said at least one perimeter chamber (9a; 9c; 109a; 109c), in which said central chamber (9b; 109b) and said at least one perimeter chamber (9a; 9c; 109a; 109c) are fluidically separated, and in which each of said central chamber and at least one perimeter chamber (9a; 9b; 9c; 109a; 109b; 109c) comprises at least its own mixer (8a ; 8b; 8c; 108a; 108b; 108c) with a radial type Venturi effect fed by a relative injector (6a; 6b; 6c; 106a; 106b; 106c) housed in said lower cup (1; 101), characterized in that said lower cup (1; 101) comprises for each of said injectors (6a; 6b; 6c; 106a; 106b; 106c) a relative housing (5a; 5b; 5c; 105a; 105b; 105c), each of said housings (5a ; 5b; 5c; 105a; 105b; 105c) for said injectors (6a; 6b; 6c; 106a; 106b; 106c) being fluidically separated from each of the other housings (5a; 5b; 5c; 105a; 105b; 105c), at least when said intermediate body (2; 102) of the burner (10; 110) ? bound to said lower cup (1; 101). 2. Atmospheric gas burner (10; 110) according to claim 1, wherein said intermediate body (2; 102) of the burner comprises a central chamber (9b; 109b) for delivering the combustible mixture which is? equipped with its own central flame divider, and two perimeter chambers (9a; 9c; 109a; 109c) for delivering the combustible mixture, which at least partially surround said central chamber (9b; 109b) and in which each of them ? ? equipped with at least one perimeter flame divider, said two perimeter chambers and said central chamber being fluidly separated from each other. 3. Atmospheric gas burner (10; 110) according to claim 2, wherein each of said two perimetric chambers (9a; 9c; 109a; 109c) for delivering the combustible mixture has a substantially semi-annular shape. 4. Atmospheric gas burner (10; 110) according to claim 1, 2 or 3, characterized in that the flame holes of each flame divider are shaped to direct the outgoing combustible mixture horizontally. 5. Atmospheric gas burner (10; 110) according to any one of the preceding claims, wherein each of said radial-type Venturi effect mixers (8a; 8b; 8c; 108a; 108b; 108c) comprises a disc-shaped expansion chamber combustible mixture that ? at least partially defined at the top by said means (3a, 3b; 103) for the upper covering of said delivery chambers (9a; 9b; 9c; 109a; 109b; 109c) of the intermediate body (2; 102) of the burner. 6. Atmospheric gas burner (10; 110) according to any one of the preceding claims, comprising means for feeding primary air (A) into said mixers (8a; 8b; 8c; 108a; 108b; 108c) with radial Venturi effect, said means to supply primary air comprising primary air inflow openings which are placed above said shelf (4; 104) of the cooking appliance or alternatively below said shelf (4; 104) of the cooking appliance . 7. Atmospheric gas burner (10; 110) according to any one of the preceding claims, wherein said top cover means comprises a separate cover (3a, 3b) for at least two of said delivery chambers (9a; 9b; 9c; 109a; 109b; 109c) of the combustible mixture. 8. Atmospheric gas burner (10; 110) according to any one of claims 1 to 6, wherein said means for the top cover comprises a lid (103) made in one piece for covering the ? said delivery chambers (9a; 9b; 9c; 109a; 109b; 109c) of the combustible mixture. 9. Atmospheric gas burner (10; 110) according to any one of the preceding claims, wherein said at least one perimetric delivery chamber (9a; 9c; 109a; 109c) comprises at least one flame-spreader with flame holes facing towards the outside. outside of the burner or comprises two flame dividers, one facing said central delivery chamber, the other facing towards the outside of the burner. 10. Atmospheric gas burner (10; 110) according to any one of the preceding claims, wherein the fuel gas flows within said injectors (6a; 6b; 6c; 106a; 106b; 106c) housed in the lower sump (1; 101) are regulated by a single gas tap or alternatively by two or more? separate gas taps.