CN113966450A

CN113966450A - Gas burner

Info

Publication number: CN113966450A
Application number: CN202080043070.9A
Authority: CN
Inventors: 马西莫·多拉
Original assignee: Sabaf SpA
Current assignee: Sabaf SpA
Priority date: 2019-05-28
Filing date: 2020-05-19
Publication date: 2022-01-21
Also published as: WO2020240345A1; IT201900007440A1; KR20220010032A

Abstract

Gas burner (1) of the type comprising: -a burner cup (2) provided with at least one gas injection nozzle (3); -at least one mixer (4) for mixing the gas with the primary air (I), said mixer (4) being placed downstream of said at least one injection nozzle (3) and feeding the gas through said at least one injection nozzle; -a burner body (5) placed downstream of said mixer (4) and removably coupled with said burner cup (2), said burner body (5) comprising at least one distribution chamber (6) of a mixture consisting of gas and primary air (I); -at least one groove (8) arranged downstream of the injection nozzle (3) and upstream of the mixer (4) and provided with at least one opening (9), said opening (9) being intended to let primary air (I) flow into said groove to mix with the injection gas inside the mixer; -wherein the groove (8) comprises means (10) for regulating the primary air flowing into the mixer (4) through the at least one opening (9); characterized in that said adjustment means (10) are rotatably constrained to said groove (8) so as to at least partially cover said at least one opening (9) within the angular range of the reaching position.

Description

Gas burner

Technical Field

The present invention relates to a gas-fired burner, in particular a household burner for cooking food.

Background

According to the known art, a gas burner, in particular of the household type intended for cooking food, comprises: a burner cup provided with a gas injection nozzle; a mixer for mixing the gas with the primary air, placed downstream of the injection nozzle and fed with the gas through the injection nozzle; a burner body removably coupled with the burner cup and comprising a distribution chamber of a mixture consisting of gas and primary air, placed downstream of the mixer; and a groove disposed downstream of the injection nozzle and upstream of the mixer, and provided with an opening for inflow of the primary air.

The opening of the recess is dimensioned to have an exact stoichiometric ratio with the supply gas of the burner. In particular, the mixture from the introduced primary air and the injected gas has a composition such that, in the case of subsequent supply of secondary air, it can suitably trigger the ignition of the burner according to the design specifications of the burner itself. Thus, the flame of the burner is stable.

Unfortunately, the same burner model does not work effectively in countries or regions where the gas supplied to the burner and/or its pressure is different from the gas and/or its pressure for which the particular burner is designed. In fact, in this case, the stoichiometric ratio between primary air and feed gas is different from the designed stoichiometric ratio and therefore the flame is unstable. Furthermore, the pressure of the gas used may also be different from the pressure designed in these regions.

In countries or regions where the feed gas has a different composition than the gas for which a particular burner design is intended, installers attempt to remedy this by employing mechanisms that allow the inflow flow rate of the primary air to be varied, so that the stoichiometric composition of the gas/primary air mixture, with the supply of an appropriate amount of secondary air, allows a stable flame, and thus ensures perfect performance of the burner, while ensuring compliance with safety regulations regarding the use of such products. However, the setup of the installer is done in an easy way, and therefore the quality of the work done on the burner is based only on the installer's own experience. Furthermore, the measures taken by the installer cannot be considered safe anyway.

The object of the present invention is therefore to achieve a burner that can be easily adjusted to operate according to the design specifications, independently of the gas used.

Another object of the present invention is to achieve a gas burner that is simple from a structural point of view and that can solve the above technical problems without requiring significant efforts of the installer.

Disclosure of Invention

These and other objects are achieved by a gas burner of the type comprising:

-a burner cup provided with at least one gas injection nozzle;

-at least one mixer for mixing gas with primary air, said mixer being placed downstream of said at least one injection nozzle and feeding gas through said at least one injection nozzle;

-a burner body placed downstream of said mixer and removably coupled with said burner cup, comprising at least one distribution chamber of a mixture consisting of gas and primary air; and

-at least one groove arranged downstream of the injection nozzle and upstream of the mixer and provided with at least one opening for the inflow of primary air into the groove to mix with the injected gas inside the mixer;

-wherein the recess comprises means for regulating the flow of primary air into the mixer through the at least one opening;

characterized in that said adjustment means are rotatably constrained to said groove to at least partially cover said at least one opening within an angular range of the reaching position.

This solution allows achieving the proposed objects. In fact, the installer will no longer be forced to take simple measures to remedy the site to allow the burner to operate, for example with a continuous flame, but simply intervene, rotating the means of regulating the air inflow with respect to the opening of the groove, to vary the inlet section of the opening itself and therefore the flow rate of the primary air inflow. Thus, depending on the composition of the gas delivered in the area where the burner is installed, the installer can easily and quickly intervene, making the burner work according to the design conditions and ensuring maximum safety of the burner itself.

According to the invention, the burner comprises such means: for reversibly locking the adjustment means to the groove directly or indirectly in a plurality of different angular positions within the angular range. In practice, therefore, not only can the adjusting device be angularly varied in a plurality of positions, but this also keeps the adjusting device locked in a certain number of positions. The adjustment device is therefore only advanced to the successive position when it passes the locking portion constituted by the reversible locking device.

In particular, the reversible locking means comprise at least one protrusion, which is directly or indirectly integral with the adjustment means or with the groove, and one or more recesses, which is directly or indirectly integral with the at least one groove or with the adjustment means and which, during rotation of the adjustment means, can be shape-coupled with the at least one protrusion. Thus, the adjustment device is locked in a given angular position corresponding to the point at which the projection couples with the recess, or to the point at which the recess couples with the projection. The adjustment device must be rotated by the installer with a certain force so that the protrusion can come out of the recess to overcome the coupling.

According to the invention, the injection nozzle is constrained to the first wall of the recess and is oriented so as to inject the combustion gas in a direction such that: the direction is different from an entry direction of the primary air through the at least one opening.

Preferably, the opening of the groove is located on a plane whose normal line is orthogonal to the injection direction of the fuel gas.

Preferably, the opening of the recess lies in a plane.

According to a first embodiment of the invention, the adjustment means comprise at least one sleeve which is substantially cylindrical and has a longitudinal axis parallel to the injection direction of the combustion gases. Furthermore, the sleeve is rotatably constrained within the groove about the longitudinal axis and is provided with at least one channel to allow a primary air flow into the groove at least when the channel at least partially overlaps the opening. Thus, in practice, by suitably rotating the sleeve, the area of overlap between the openings of the grooves and the channels on the sleeve can be varied, and therefore the flow rate of the primary air introduced into the burner can be varied. Thus, if the passage completely overlaps the opening, the burner is within the design conditions, whereas if the passage only partially overlaps the opening, the flow rate of the primary air is reduced relative to the designed flow rate. As the area of overlap between the openings and the channels present on the sleeve progressively decreases, the flow rate of the primary air decreases up to zero or close to zero (whenever such overlap is no longer present).

Always according to the embodiments described so far, said longitudinal axis of the sleeve is parallel and/or coincident with the injection direction of said gas from said at least one injection nozzle.

Furthermore, the channel extends along the longitudinal axis of the sleeve and has a radial extension smaller than or equal to the opening.

Furthermore, the sleeve comprises a base provided with a central hole, such that the spray nozzle is arranged to protrude into the sleeve through the central hole.

Advantageously, said at least one projection is integral with said base of said sleeve and said one or more recesses are integral with said at least one first wall of said groove and can be shape-coupled with said at least one projection; the recess is formed along a circumference concentric with the longitudinal axis. Thus, the base is removably coupled with the first wall of the groove in a plurality of different angular positions.

This allows the flow rate of the primary air flowing in through the passage formed on the sleeve to be accurately adjusted. In fact, the recesses may be formed at precise angular distances, such as every 30 °, and therefore, when the knob is progressively rotated, an overlap is obtained between the channel and the different and anyway well-calibrated opening.

Further, the base includes one or more weakened notches to allow the sleeve to rotate relative to the groove. In fact, disengagement between the projection and the recess only occurs if the base is slightly deformable during rotation of the sleeve.

Furthermore, the recess comprises a second wall opposite the first wall, wherein the longitudinal extension of the sleeve is equal to the distance between the first wall and the second wall. Thus, the sleeve is perfectly built in the groove.

Also, the first wall of the groove is removably constrained to the groove.

Advantageously, the second wall comprises a substantially cylindrical recess having a diameter substantially equal to the diameter of the sleeve. Such a second wall thus guides the sleeve to facilitate its rotation within the groove. This rotation is stopped each time the projection of the base couples with the recess obtained on the first wall. Due to the deformability of the base, the protrusion is obtained from the recess due to the presence of one or more notches as described above.

According to a second embodiment of the invention, said adjustment means comprise at least one first fin, which is rotationally constrained with respect to said groove about a first axis substantially orthogonal to said plane in which said opening of said groove lies, so as to at least partially cover said at least one opening.

In a variant of this second embodiment, the adjustment means comprise at least one second fin, which is rotationally constrained with respect to the groove about a second axis substantially orthogonal to the plane in which the opening of the groove lies, so as to at least partially cover the at least one opening.

Advantageously, the adjustment device further comprises means for simultaneously rotating the first fin and the second fin during rotation of the first fin or the second fin.

The mechanism for simultaneous rotation includes a first cogwheel portion integral with the first fin and a second cogwheel portion integral with the second fin; the simultaneous rotation mechanism further comprises a third cogwheel and a fourth cogwheel coupled to each other and to the first cogwheel portion and the second cogwheel portion, respectively, such that the same rotation of the second fin in opposite directions corresponds to the rotation of the first fin, or vice versa.

Advantageously, said at least one projection is integral with said at least one first fin and said one or more recesses are integral, directly or indirectly, with said groove and can be shape-coupled with said at least one projection; the one or more recesses are formed along a circumference concentric with the first axis.

Preferably, said groove comprises an upper locking clamp for said mechanism of simultaneous rotation, said upper locking clamp being constrained integrally with said groove and provided with at least one hole for the passage of at least one pin concentric with said first axis; the one or more recesses are integral with the locking clamp.

One or more notches are formed on the first fin to allow disengagement between the protrusion and the recess.

Drawings

These and other aspects of the present invention will become more apparent in the following detailed description of the preferred embodiments presented herein, which are provided by way of example only and not by way of limitation, with reference to the accompanying drawings, in which:

FIG. 1A is an isometric view of a burner according to a first embodiment of the invention;

FIG. 1B is a bottom view of the burner of FIG. 1A;

FIG. 1C is a longitudinal cross-sectional view of the combustor shown in FIG. 1B;

fig. 2A is an isometric view of a sleeve of an adjustment device, in particular according to a first embodiment, in which the flow rate of primary air into the groove is maximum;

fig. 2B is an isometric view of a sleeve of the regulating device, in particular according to the first embodiment, in which the flow rate of the primary air entering the groove is reduced with respect to that of fig. 2A;

FIG. 3A is an isometric view of the wall of a first groove in combination with a spray nozzle and a sleeve;

FIG. 3B is an isometric view of the walls of only the first groove in combination with the spray nozzle;

FIG. 3C is an isometric view of the sleeve only;

FIG. 4A is a top view of a cup of a burner according to a second embodiment of the present invention;

FIG. 4B is a longitudinal cross-sectional view of the burner cup of FIG. 4A;

FIG. 4C is an isometric view of the burner cup of FIG. 4A, wherein the adjustment device includes a first fin and a second fin, and wherein the first fin is shown in both a position to allow full access of primary air through the opening of the slot and a rotational position to allow access of primary air through the opening portion of the slot;

FIG. 5A is a detailed isometric view of the adjustment device of the burner shown in FIGS. 4A-4C;

FIG. 5B is a detailed partially exploded isometric view of the tuning assembly of the burner shown in FIGS. 4A-4C, with the primary air being admitted completely through the opening of the recess;

FIG. 5C is a detailed partially exploded isometric view of the tuning assembly of the burner shown in FIGS. 4A-4C, wherein primary air is admitted through the open portion of the recess;

FIG. 5D is a detailed partially exploded isometric view of the tuning assembly of the burner shown in FIGS. 4A-4C, with reduced ingress of primary air allowed through the openings of the flutes relative to that shown in FIG. 5C;

FIG. 6A is a detailed partially exploded isometric view of a variation of the burner shown in FIGS. 4A-4C and 5A-5D, wherein there is a reversible locking device of the adjustment device;

fig. 6B is a detailed and partially exploded isometric view of fig. 6A.

Detailed Description

With particular reference to these figures, 1 denotes a burner according to the present invention.

According to a first embodiment of the invention, in fig. 1A gas burner 1 is shown, which gas burner 1 comprises: a burner cup 2 provided with a gas injection nozzle 3; a mixer 4 for mixing the gas with the primary air I, the mixer 4 being placed downstream of the injection nozzle 3 and being fed with gas through the injection nozzle 3; a groove 8 arranged downstream of the injection nozzle 3 and upstream of the mixer 4 and provided with an opening 9 for the primary air I to flow into the groove 8 to be mixed with the injection gas inside the mixer 4. Advantageously, the groove 8 comprises means 10 to regulate the primary air flow into the mixer 4 through two openings 9 arranged opposite each other. Such adjustment means 10 are rotatably constrained to the groove 8 to at least partially cover the opening 9 within the angular range of the position reached by the adjustment means 10.

It should be observed that in embodiments not illustrated herein, the presence of a single opening 9 or a plurality of openings 9 greater than two would anyway fall within the scope of protection of the present invention.

In a known manner, the burner 1 also comprises a burner body 5, the burner body 5 being placed downstream of the mixer 4 and being removably coupled with the burner cup 2, the burner body 5 comprising a distribution chamber 6 of a mixture consisting of gas and primary air I.

Still according to the invention, the injection nozzles 3 are constrained to the first wall 8a of the groove 8. The injection nozzles 3 are oriented so as to inject the gas in a direction X different from the direction Y of entry of the primary air I through the openings 9 of the grooves 8.

Preferably, each opening 9 of the groove 8 is located on a flat surface V. Preferably, the flat surface V is horizontal. More preferably, the normal to such a flat surface V is orthogonal to the injection direction X of the combustion gases.

According to a particular aspect of the first embodiment of the invention, the adjustment device 10 comprises a sleeve 11, the sleeve 11 being substantially cylindrical and having a longitudinal axis L parallel to the injection direction X of the combustion gases. Such a sleeve 11 is rotatably constrained around a longitudinal axis L inside the groove 8 and is provided with two channels 12 to allow the primary air I to flow into the groove 8 at least when each channel 12 at least partially overlaps the respective opening 9. The two channels 12 are arranged in opposite positions with respect to each other. In practice, the installer must simply rotate the sleeve 11 until the cross-over area of the primary air I is obtained, for example to ensure the maintenance of the flame, which also takes into account the continuous supply of secondary air. This is simply achieved. In fact, as better shown in the figures, each channel 12 changes area as the sleeve 11 rotates, the channel 12 being completely hidden inside the groove 8 whenever it is necessary to completely prevent the passage of the primary air I through the groove 8. Thus, passage of the primary air I is only obtained if the passage 12 and the opening 8 even only partially overlap one another.

Here, it should also be observed that, in embodiments not illustrated herein, the presence of a single channel 12 or a number of recesses greater than two would anyway fall within the scope of protection of the present invention.

This solution allows achieving the proposed objects. In fact, the installer will no longer be forced to take simple measures of field remedy to allow the burner to work, for example with a continuous flame, but only to simply dry the means of pre-conditioning the air inflow, by rotating them with respect to the openings of the grooves in order to vary the inlet section of the openings themselves and thus the flow rate of the primary air inflow. Thus, based on the composition of the gas delivered in the area where the burner is installed, the installer can easily and quickly intervene, ensuring maximum safety of the burner itself by making it work according to the design conditions.

In particular, the longitudinal axis L coincides with the gas injection direction X from the injection nozzle 3.

Each channel 12 extends along the longitudinal axis L of the sleeve 11 and has a radial extension slightly smaller than that of the respective opening 9.

Still according to the invention and as better shown in fig. 3A to 3C, the sleeve 11 comprises a base 14 provided with a central hole 15, so that the injection nozzle 3 is arranged to protrude into the sleeve 11 through the central hole 15.

According to the invention, the burner 1 comprises means 13 for reversibly locking the adjustment means 10 (i.e. the sleeve 11) to the groove 8 in a plurality of different angular positions within the above-mentioned angular range.

Such a reversibly lockable means 13 comprises two protrusions 16, said protrusions 16 being integral with the adjustment means 10, and a plurality of recesses 17, said recesses 17 being integral with said grooves 8 and shape-couplable to the protrusions 16 during rotation of the adjustment means 11.

In particular, the two projections 16 are integral with the base 14 of the sleeve 11 and the recess 17 is integral with the first wall 8a of the groove 8 and can be shape-coupled to the two projections 16. The recess 17 is formed along a circumference C concentric with the central hole 15.

Thus, the base 14 is removably coupled to the first wall 8a of the groove 8 in a plurality of different angular positions. In this way, once the precise angular position of the sleeve 11 with respect to the groove 8 has been determined, and therefore the precise opening area of the channel 12, the installer will in a later installation only need to install the burner by positioning the sleeve 11 at the same degree of rotation, in order to achieve a result that is always constant.

The base 14 also comprises two weakening notches 18 shaped like a quarter of a circle to allow the sleeve 11 to rotate with respect to the groove 8 after deformation of the base adapted to promote coupling between the projection 16 and the recess 17 coupled thereto.

The recess 8 comprises a second wall 8b opposite the first wall 8a, wherein the longitudinal extension P of the sleeve 11 is equal to the distance between the first wall 8a and the second wall 8 b. In particular, the second wall 8b comprises a substantially cylindrical concave portion, the diameter of which is substantially equal to the diameter of the sleeve 11.

A second embodiment of a burner 1 according to the invention is shown in fig. 4A-4C and 5A-5C.

Also in this case, the gas burner 1 comprises: a burner cup 2 provided with a gas injection nozzle 3; a mixer 4 for mixing the gas with the primary air I, said mixer 4 being placed downstream of the injection nozzle 3 and feeding the gas through the injection nozzle 3; a groove 8 arranged downstream of the injection nozzle 3 and upstream of the mixer 4, and the groove 8 is provided with openings 9 for the primary air I to flow into the groove for mixing with the injection gas inside the mixer 4. Furthermore, the opening 9 of the groove 8 lies in the V-plane. Advantageously, the groove 8 comprises means 10 to regulate the flow of primary air I into the mixer 4 through the opening 9. Such adjustment means 10 are rotatably constrained to the groove 8 to at least partially cover the opening 9 within the angular range of the position reached by the adjustment means 10.

In a known manner, the burner 1 of the second embodiment of the invention also comprises a burner body 5, however, for the sake of simplicity, the burner body 5 is not shown in the figures.

Still according to the invention, the injection nozzles 3 are constrained to the first wall 8a of the groove 8. The injection nozzle 3 is oriented so as to inject the combustion gases in a direction X substantially different from the direction of entry Y of the primary air I through the openings 9 of the grooves 8 (such direction of entry Y is not shown in the figures depicting the second embodiment).

In the embodiment described herein, the adjustment device 10 comprises a first fin 20, the first fin 20 being rotationally constrained with respect to the groove 8 about a first axis a substantially orthogonal to the plane V in which the opening 9 of the groove 8 lies, so as to at least partially cover the opening 9. The plane V is preferably horizontal.

The adjustment device 10 further comprises a second fin 21, the second fin 21 being rotationally constrained with respect to the groove 8 about a second axis B substantially orthogonal to the plane V in which the opening 9 of the groove 8 lies, so as to at least partially cover the opening 9.

According to a variant of this second embodiment, a burner 1 comprising only the first fins 20 would anyway fall within the scope of protection of the present invention.

Moreover, the adjustment device 10 comprises a mechanism 30 for simultaneously and oppositely rotating the first fin 20 and the second fin 21 during the rotation of the first fin 20 or the second fin 21. In this way, when, for example, the first fin 20 is rotated to cover the opening 9 of the groove 8, the second fin 21 is also rotated in a direction opposite to the direction of rotation of the first fin 20 to at least partially cover the opening 9. Since the rotation performed by the two

fins

20 and 21 is identical, the passage area of the primary air I is perfectly centred in the groove 8, although in the opposite direction, avoiding an asymmetrical flow of the air/gas mixture entering the mixer 4.

According to a particular embodiment, the mechanism 30 of simultaneous rotation comprises a first cogwheel portion 40 integral with the first fin 20 and a second cogwheel portion 41 integral with the second fin 21. The mechanism 30 of simultaneous rotation further comprises a third cogwheel 42 and a fourth cogwheel 43, the third cogwheel 42 and the fourth cogwheel 43 being coupled to each other and to the first cogwheel portion 40 and the second cogwheel portion 41, respectively, so that the same rotation of the second fins 21 in opposite directions corresponds to the rotation of the first fins 20, or the same rotation of the first fins 20 in opposite directions corresponds to the rotation of the second fins 21. The presence of the above-mentioned gear train also allows to precisely rotate the

fins

20 and 21, thus making fine adjustments to the flow rate of the primary air I entering the burner 1. The third cogwheel 42 and the fourth cogwheel 43 rotate about a third axis C and a fourth axis D, respectively, which are parallel to the first axis a and to the second axis B, i.e. orthogonal to the plane V in which the opening 9 of the groove 8 lies. The groove 8 also includes an upper locking clamp 50 of the rotation mechanism 30. The locking clamp 50 has four

holes

51a, 51b, 51c, 51 d. Each

hole

51a, 51b, 51c, 51d is occupied by a

respective pin

52a, 52b, 52c, 52d for rotation of the respective gear train to which it is coupled (i.e. first cogwheel portion 40, second cogwheel portion 41, third cogwheel 42, and fourth cogwheel 43). In particular, pins 52a and 52d have heads adapted to lock clamp 50 to groove 8.

Fig. 6A and 6B show a modification of the second embodiment of the present invention. This variant provides the presence of means 13 for reversibly locking the adjustment means 10 (i.e. the first fin 20) at the groove 8 in a plurality of different angular positions within the angular range described above.

This reversibly lockable means 13 comprise a projection 16 integral with the first fin 20 and a plurality of recesses 17 indirectly integral with the groove 8. Such a recess 17 may also be shape-coupled to the protrusion 16 and formed along a circumference C concentric to the first axis a about which the first fin 20 rotates.

In particular, the upper locking clamp 50 for the rotation mechanism 30 is integrally constrained to the groove 8 and is provided with a hole for the passage of a pin 52a, the pin 52a being concentric with the first axis a. The recess 17 is thus integral with the locking clamp 50 and thus with the groove 8.

This allows the flow rate of the primary air I flowing in through the opening 9 formed on the plane V to be accurately adjusted. In fact, the recesses 17 can be formed at precise angular distances, for example every 30 °, and therefore when the first fins 20 are progressively rotated, the inlet portion of the primary air I is obtained through different but well-calibrated openings 9.

Furthermore, the first fin 20 comprises two weakening notches 18 to allow rotation with respect to the axis a.

This solution allows fine adjustment of the range of passage area of the primary air I through the openings 9 of the grooves 8, so that the installer can adjust the flow rate of the primary air I in a simple, repeatable and safe manner, depending on the composition of the gas supplied.

Claims

1. Gas burner (1), comprising:

-a burner cup (2) provided with at least one gas injection nozzle (3);

-at least one mixer (4) for mixing the gas with the primary air (I), said mixer (4) being placed downstream of said at least one injection nozzle (3) and feeding the gas through said at least one injection nozzle;

-a burner body (5) placed downstream of said mixer (4) and removably coupled with said burner cup (2), said burner body (5) comprising at least one distribution chamber (6) for a mixture consisting of gas and primary air (I);

-at least one groove (8) arranged downstream of the injection nozzle (3) and upstream of the mixer (4) and provided with at least one opening (9), said opening (9) being intended to let primary air (I) flow into said groove to mix with the injection gas inside the mixer;

-wherein said recess (8) comprises means (10) for regulating the inflow of primary air into said mixer (4) through said at least one opening (9);

characterized in that said adjustment means (10) are rotatably constrained to said groove (8) so as to at least partially cover said at least one opening (9) within the angular range of the reaching position.

2. Burner according to claim 1, comprising means (13) for reversibly locking said adjusting means to said groove directly or indirectly in a plurality of different angular positions within said angular range.

3. Burner according to claim 2, characterized in that said reversible locking means comprise at least one protrusion (16) and one or more recesses (17), said at least one protrusion (16) being directly or indirectly integral with said adjusting means or said groove, said one or more recesses (17) being directly or indirectly integral with said at least one groove or said adjusting means, and said one or more recesses (17) being capable of shape coupling with said at least one protrusion during rotation of said adjusting means.

4. A burner according to one or more of claims 1 to 3, characterized in that said injection nozzle (3) is constrained to a first wall (8a) of said groove (8), said injection nozzle (3) being oriented so as to inject said combustion gases in a direction (X) different from an entry direction (Y) of said primary air through said at least one opening (9).

5. Burner according to one or more of claims 1 to 4, characterized in that said opening of said groove lies on a plane (V).

6. A burner according to one or more of claims 1 to 5, characterized in that said adjusting means (10) comprise at least one sleeve (11), said sleeve (11) being substantially cylindrical and having a longitudinal axis (L) substantially parallel to the injection direction (X) of said combustion gases, said sleeve (11) being rotatably constrained within said groove (8) about said longitudinal axis (L), and being provided with at least one passage (12) so as to allow the inflow of primary air into said groove at least when said passage (12) at least partially overlaps said opening (9).

7. Burner according to claim 6, wherein said longitudinal axis (L) is parallel and/or coincident with an injection direction (X) of said gas from said at least one injection nozzle (3).

8. A burner according to claim 6 or 7, characterized in that said channel (12) extends along said longitudinal axis (L) of said sleeve (11) and has a radial extension less than or equal to said opening.

9. A burner according to one or more of claims 2 to 8, characterized in that said sleeve (11) comprises a base (14) provided with a central hole (15), so that said nozzle (3) is arranged to protrude into said sleeve (11) through said central hole (15).

10. A burner according to claim 9, characterized in that said at least one protrusion (16) is integral with said base (14) of said sleeve (11) and said plurality of recesses (17) is integral with said at least one first wall (8a) of said groove (8), and said plurality of recesses (17) are shape-couplable with said at least one protrusion (16), said recesses being formed along a circumference (C) concentric with said longitudinal axis (L).

11. A burner according to claim 10, wherein the base (14) comprises one or more weakening notches (18) to allow the sleeve (11) to rotate relative to the groove (8).

12. A burner according to one or more of the preceding claims, characterized in that said groove (8) comprises a second wall (8b) opposite to said first wall (8a), wherein the longitudinal extension (P) of said sleeve (11) is equal to the distance between said first wall (8a) and said second wall (8 b).

13. A burner according to one or more of the preceding claims, characterized in that said second wall (8b) comprises a substantially cylindrical recess having a diameter substantially equal to the diameter of said sleeve (11) to guide said sleeve (11) during the rotation of said sleeve (11).

14. A burner as claimed in one or more of claims 2 to 13, characterised in that said first wall (8a) of said groove (8) is removably constrained to said groove.

15. Burner according to one or more of claims 1 to 5, characterized by the fact that said adjusting means (10) comprise at least one first fin (20) which is rotatably constrained with respect to said groove (8) about a first axis (A) substantially orthogonal to said plane (V) in which said opening (9) of said groove (8) lies, so as to cover at least partially said at least one opening (9).

16. Burner according to claim 15, wherein said adjusting means (10) comprise at least one second fin (21) rotatably constrained with respect to said groove about a second axis (B) substantially orthogonal to said plane (V) in which said opening (9) of said groove (8) lies, so as to cover at least partially said at least one opening (9).

17. Burner according to claims 15 and 16, characterized in that said adjustment means (10) comprise means (30) for rotating said first fin (20) and said second fin (21) simultaneously and reciprocally during the rotation of said first fin or said second fin.

18. Burner according to claim 17, wherein said means for simultaneous rotation (30) comprise a first cogwheel portion (40) and a second cogwheel portion (41), said first cogwheel portion (40) being integral with said first fin (20) and said second cogwheel portion (41) being integral with said second fin (21), said means for simultaneous rotation (30) further comprising a third cogwheel (42) and a fourth cogwheel (43) coupled to each other and to said first cogwheel portion (40) and to said second cogwheel portion (41), respectively, so that the same rotation of said second fin (21) in opposite directions corresponds to the rotation of said first fin (20) or vice versa.

19. Burner according to claim 15, characterized in that said at least one protrusion (16) is integral with said at least one first fin (20) and in that said one or more recesses (17) are integral, directly or indirectly, with said groove (8) and are capable of shape coupling with said at least one protrusion (16), said one or more recesses being formed along a circumference (C) concentric with said first axis (a).

20. Burner according to claim 19, wherein said groove comprises an upper locking clamp for constraining integrally with said groove and provided with said rotation means of at least one hole for passing said one pin concentric to said first axis (a), said one or more recesses (17) being integral with said locking clamp (50).