ES2600565T3 - Gaseous fuel burner - Google Patents

Abstract

Gaseous fuel burner (1) comprising, on the one hand, a central air supply duct (2) that flows into a home and is delimited by a central air supply tube (3) around which a wall extends (4) which delimits the outdoor home and, on the other hand, fuel gas supply devices (5) that are arranged in the central air supply duct (2) and flow directly into the home, each device comprising fuel gas supply (5) a fuel gas supply line (6) delimited by a fuel gas supply tube (7) whose downstream end carries an injection nozzle (8), the burner (1) comprising organs which form a screen (11) that partially obstructs the central air supply duct (2), each screen-forming organ (11) extending along a plane parallel to the general plane of the opening downstream of the co central air supply duct (2), at the height of the downstream end of the corresponding fuel gas feeding device (5), characterized in that the set of the screen-forming organs (11) forms a radially extending ring from the inner wall of the central air supply tube (3), over 360º, to deplete the area where the combustible gas enters the home with oxygen.

Description

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DESCRIPTION

Gaseous fuel burner

The present invention relates to a gas fuel burner or a mixed gas / liquid burner.

A gas fuel burner of the type is known which comprises, on the one hand, a central air supply duct that flows into a home and is delimited by a central air supply tube around which a wall that delimits the wall extends. home from outside and, on the other hand, fuel gas supply devices that are arranged in the central air supply duct and that flow directly into the home, each fuel gas feeding device comprising a fuel gas feeding conduit bounded by a fuel gas supply tube whose downstream end carries an injection nozzle.

A burner of this type is described in European patent application EP 1 074 790 in which each fuel gas supply device is constituted by the fuel gas supply conduit and by a smoke circulation conduit into which the injection nozzle, each smoke circulation duct being delimited by a smoke circulation tube in which a lateral smoke intake opening is angularly turned outwards from the central air supply tube, the end being upstream of the Smoke circulation duct obstructed by a plate crossed by the fuel gas supply duct, leading its end downstream directly into the home. European patent application EP-0 675 321 also describes such a burner.

Fuel gas supply devices of this type allow reducing the rate of nitrogen oxides emitted.

The present invention also aims to reduce the rate of nitrogen oxides emitted.

According to the invention, the burner of the aforementioned type comprises screen-forming organs, as defined in claims 1 and 4, which partially obstruct the central air supply duct, each organ extending, according to a plane parallel to the general plane from the opening downstream of the central air supply duct, from the corresponding fuel gas feeding device, to the height of the downstream end of this device, to deplete the area where the combustible gas enters the home with oxygen .

In this way, this organ hinders and modifies the circulation of the air that comes from the central feeding duct so that it cannot circulate in the immediate proximity of the downstream end. In this way, the zone of introduction of the gaseous fuel in the home can be described as a dead zone in which the fuel is mixed with the surrounding fumes, which allows to reduce the lower caloric power of the mixture and, therefore, the rate of nitrogen oxides.

Other particularities and advantages will be shown in the description of seven embodiments of the present invention given by way of non-limiting examples and illustrated by the drawings that are attached in which:

Figure 1 is a schematic front view of a burner according to a first embodiment,

Figure 2 is a partial schematic front view of a burner according to a second mode of

realization,

Figure 3 is a schematic view in longitudinal section of the half of a burner according to the second embodiment,

Figure 4 is a view similar to Figure 2 of a burner according to a third embodiment,

Figure 5 is a view similar to Figure 2 of a burner according to a fourth embodiment,

Figure 6 is a view similar to Figure 2 of a burner according to a fifth embodiment,

Figure 7 is a view similar to Figure 2 of a burner according to a sixth embodiment,

Figure 8 is a view similar to Figure 2 of a burner according to a seventh embodiment, Figure 9 is a view similar to Figure 3 corresponding to the burner according to the sixth embodiment, Figure 10 is a view similar to Figure 2 of a burner according to an eighth embodiment, Figure 11 is a view similar to Figure 3 of a burner according to the eighth embodiment,

Figure 12 is a view similar to Figure 3 of a burner according to a ninth embodiment,

Figure 13 is a view similar to Figure 3 of a burner according to a tenth embodiment,

Figure 14 is a view similar to Figure 2 of a burner according to the tenth embodiment,

Figure 15 is a view similar to Figure 3 of a burner with gates,

Figure 16 is a view similar to Figure 3 of the burner of Figure 15 modified to form a tenth embodiment of the present invention, the cut being made according to line XVI-XVI of Figure 17 and Figure 17 is a view similar to figure 2 of the burner of figure 15 modified to form the tenth embodiment of the present invention.

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Each of Figures 1 to 14 represents a gaseous fuel burner 1. A burner 1 of this type comprises a central air supply duct 2 that flows into a home. This central air supply duct 2 is delimited by a central air supply tube 3 around which a wall 4 that delimits the exterior home is extended.

On the other hand, the burner 1 also comprises and, on the other hand, fuel gas supply devices 5 (in this case, six devices 5) which are arranged in the central air supply duct 2 and which flow directly into the home. These fuel gas supply devices 5 are distributed angularly on a regular basis. Each fuel gas supply device 5 comprises a fuel gas supply conduit 6 which is delimited by a fuel gas supply tube 7 whose downstream end carries an injection nozzle 8.

In addition, the burner 1 comprises a flame stabilizing device 9 which is arranged on the axis 10 of the central air supply duct 2.

In the present embodiments, the burners 1 also comprise a central liquid fuel supply line 22 that flows into the center of the flame stabilizer (downstream of this) and which is delimited by a central liquid fuel supply tube 23 .

According to the invention, as this can be seen in the different figures 1 to 14, the burner 1 comprises screen-forming organs 11 that partially obstruct the central air supply duct 2, each screen-forming organ 11 extending according to a parallel plane to the general plane of the opening downstream of the central air supply duct 2, in the vicinity of the downstream end of the corresponding fuel gas feeding device 5, to deplete with oxygen the area in which the combustible gas enters the home . In this way, this zone can be considered as a dead zone (the oxygen rate can drop to about 2% - which has to be compared with the 20% rate in the air) and is the place of the gas mixture Fuel with the fumes.

Each screen-forming organ 11 extends radially from the inner wall of the central air supply tube 3.

In all embodiments, the assembly of the screen-forming organs 11 forms a ring that extends over 360 ° around the inner wall of the central air supply tube 3, except in the fourth embodiment (cf. figure 5), where the organs that form screen 11 are only present in the angular sectors where the fuel gas supply devices 5 are located.

In the first five, as well as the eighth, ninth and tenth modes of implementation, each fuel gas supply device 5 is constituted by the corresponding fuel gas supply conduit 6 and an enclosure 100. In each enclosure annex 100 which is parallel to the fuel gas supply line 6. In each enclosure 100, the fuel gas line 6 is arranged. Each enclosure 100 is laterally delimited by an annex tube 101. The upstream end of each enclosure 100 is on the other hand, it is obstructed by a plate 20 that is crossed by the fuel gas supply line 6. In this way, this plate 20 prevents the air coming from the central air supply line 2 from entering the attached tube 100. In addition , the downstream end of enclosure annex 100 flows directly into the home.

In the first five and the eighth and ninth modes of embodiment, each enclosure 100 comprises a smoke circulation duct 12 extending axially from the plane defined by the wall 4 that delimits the home from the outside, to the downstream end of the enclosure annex 100. The corresponding injection nozzle 8 flows into each flue gas duct 12 (see figure 3). Each flue gas duct 12 is laterally delimited by a flue gas pipe 13 which is the corresponding portion of the attached pipe 101. In each flue gas pipe 13 there is a side smoke intake opening 14. This side opening 14 is angularly oriented towards the outside of the central air supply tube 3, that is, it flows into an angular area occupied by the wall 4 of the hearth and, therefore, into an area without air, occupied by smoke.

In the eighth embodiment, the lateral smoke intake opening 14 extends angularly over the portion of the smoke circulation tube 13 tangent to the inner wall of the central air supply tube 3, over the entire length of the circulation tube of smoke 13.

In the first five embodiments, the entire annex enclosure 100 extending axially from the plane defined by the wall 4 that delimits the home from the outside, the upstream end of each smoke circulation duct 12 is obstructed by the plate 20.

In addition, the downstream end of the flue gas duct 12 forms the downstream end of the fuel gas supply device 5 and flows directly into the home.

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In these five embodiments, the smoke circulation tubes 13 (attached tubes 101) are arranged tangent to the inner wall of the central air supply tube 3. By this fact, the influence of the air leaving the central supply duct Air 2 is minimized. In these five embodiments, each screen-forming organ 11 extends from the external wall of the corresponding smoke circulation tube 13 (annex tube 10) corresponding.

In addition, in the third and fourth embodiments, each screen-forming organ 11 extends over 360 ° around the external wall of the corresponding smoke circulation tube 13 (annex tube 101), except at the height of the confluence of this tube 13 in the central air supply tube 3.

In the first and third embodiments, the ring constituted by the screen-forming organs 11 extends towards the interior of the central air supply duct 2 to the circle whose center is the axis 10 of the central air supply duct 2 and passing through axes 15 of the smoke circulation ducts 12 (of the enclosures annexes 100). In the second embodiment, this ring is wider and extends less to the tangent circle to the smoke circulation tubes 13 (to the attached tubes 101).

On the other hand, in the first four embodiments, the axis 15 of each smoke circulation duct 12 (the axis 15 of each enclosure 100) is the axis 16 of the corresponding fuel gas supply conduit 6. On the contrary, in the fifth embodiment, the fuel gas supply tubes 7 are arranged tangent to the inner wall of the central air supply tube 3 (more precisely, tangent to the inner wall of the smoke circulation tube 13 (from the attached tube 101) the same tangent to the inner wall of the central air supply tube 3). This particular arrangement allows each injection nozzle to be offset to the maximum 8 and, therefore, to minimize the influence of the air.

In the ninth and tenth embodiments, each annexed enclosure 100 comprises a cavity 102 that extends axially from the upstream end of the annexed enclosure 100 to the plane defined by the wall 4 that delimits the exterior home. Each cavity 102 is laterally delimited by an upstream tube 103 which is the corresponding portion of the attached tube 101. The upstream end of each cavity 102 being the upstream end of the corresponding annex 100 enclosure, is obstructed by the plate 20. In addition, In the tenth embodiment, the plate 20 comprises an opening 104 through which a smoke supply duct 105 flows through which fumes are introduced from the home and recycled outside the latter.

In the tenth embodiment, the enclosure 100 having its end downstream in the plane defined by the wall 4 that delimits the exterior home, is only formed by the corresponding cavity 102. In this embodiment, given the presence of a cavity 102 and the absence of a smoke circulation duct 12, each screen-forming organ 11 extends from the external wall of the upstream tube 103 (corresponding tube 101).

The presence of the organs that form screen 11 thereby reduces the rate of nitrogen oxides, which can be used without the burner including smoke circulation duct 12, which allows to significantly simplify the construction of the burner 1.

It occurs in this way with the tenth embodiment, where the enclosure annex 100 only comprises the corresponding cavity 102. While there is no smoke flow duct 12, the rate of nitrogen oxides produced is strongly reduced. In addition, the presence of the cavity 102 also improves the reduction of the nitrogen rate.

It also occurs in this way, in the sixth and seventh embodiments in which each fuel gas supply device 5 is constituted solely by the corresponding fuel gas supply conduit 6. Then, the injection nozzle 8 forms the downstream end of the fuel gas feeding device 5 and flows directly into the home, so that it substantially appears in the plane defined by the wall 4 that delimits the home from the outside (cf. figure 9). Due to this fact, each injection nozzle 8 is in a dead zone, substantially without oxygen, the rate being able to decrease to 2%.

In these two embodiments, each screen-forming organ 11 extends from the external wall of the corresponding fuel gas supply tube 7. In the sixth embodiment, each screen-forming organ 11 extends over 360 ° around the external wall of the corresponding fuel gas supply tube 7 and this over a distance at least equal to the diameter of the fuel gas supply tube 7 in order to minimize the influence of the air coming from the central air supply duct 2. In the same order of idea, in the seventh embodiment, the fuel gas supply tubes 7 are tangent to the inner wall of the tube central air supply 3. On the other hand, in these two examples, the ring constituted by the organs that form a screen 11 extends towards the interior of the central air supply duct 2 to the circle having the axis 10 of the center central air supply duct 2 and which is far from the wall of the central air supply tube 3 in a length equal to twice the diameter of the combustion gas supply tube ble 7.

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The presence of the organs that form screen 11 in a burner in accordance with the present invention, without annex enclosure 100 allows to divide by two the rate of nitrogen oxides emitted with respect to a burner without organs that form screen 11 and without annex enclosure 100 The additional presence of the cavity 102 without the smoke circulation duct also reduces the rate of nitrogen oxides.

Furthermore, in the present embodiments, the flame stabilizing device 9 extends radially to leave a free passage between its external radial flange 17 and the free radial edges 18 of the organs that form screen 11. Thus, the section of passage of the central air supply duct 2 can be divided into three types of zones: a first central zone from which air comes out having a flow with an angular component generated by the flame stabilizer 9, an annular zone surrounding the central zone of where air comes out that has an axial flow and an outer peripheral zone outside the other two zones, without air.

On the other hand, in order to limit the influence of the air coming from the central air supply duct 2, in the seven embodiments, the free radial edges 18 of each screen-forming organ 11 carry a protective wall 19 which is extends longitudinally along the axis 10 of the central air supply duct 2. In these embodiments, this protective wall 19 extends longitudinally on both sides of the screen forming organ 11. Furthermore, in order to improve its efficiency, this protective wall 19 is inclined at approximately 5 ° with respect to the axis 10 of the central air supply duct 2 to make the air passage section convergent.

This protective wall also allows greater flexibility in the axial position of the flame stabilizer 9 with respect to the organs that form a screen 11. In fact, without a protective wall 19, the plane of the downstream end of the stabilizer fins 9 must ( substantially) be that in which the organs that form screen 11 extend or, ultimately, may be slightly downstream of the latter. On the contrary, in the presence of the protective wall 19, the plane of the downstream end of the fins of the stabilizer 9 may be located between the two planes defined by the axial ends of the protective wall 19.

An advantage of the present invention is that it can be applied to existing burners 300, such as burners with gates, that is, whose downstream end of the air supply tube comprises a convergent section 200 followed by a divergent section 201, being the divergent section normally located in the thickness of the wall 4 delimiting the home from the outside (cf. figure 15).

In the embodiment of an existing burner, the confluence of the convergent section 200 with the divergent section 201 defines a neck 203 in the plane of which the nozzles (or equivalent) of the central gas supply lines 6, are arranged. as well as the flame stabilizer 9 and the opening (the openings) of the central liquid fuel supply line 22.

The application of the invention is illustrated by figures 16 and 17 which represent a burner 1 according to an eleventh embodiment which resembles both the sixth and seventh embodiments by the absence of an enclosure enclosed in the feeding devices of combustible gas (cf. figure 16) and to the fourth embodiment by the presence of the organs that form screen 11 only around these devices (cf. figure 17).

The renewal of the existing burner is carried out by modifying the axial position of the downstream ends of the fuel gas supply devices (which depends on the presence or absence of smoke circulation ducts). Here, the fuel gas supply devices comprising only the fuel gas supply conduits 6, their axial end is substantially arranged in the plane defined by the wall 4 that separates the home from the outside (the nozzles 8 protrude slightly in the home) .

Furthermore, in order to reduce the rate of nitrogen oxides, and in accordance with the present invention, screen-forming organs are fixed at the height of the downstream end of these devices, also at the height of the downstream end of the fuel gas supply ducts 6 (the organs that form screen 11 are arranged at the height of the plane by the wall 4 that separates the home from the outside).

In order to limit the obstruction due to the air circulating in the central air supply duct 2, the axial position of the flame stabilizer 9 and the downstream end of the central liquid fuel supply duct 22 is adapted. Here, given the absence of a protective wall along the screen-forming organs 11, the axial position of the flame stabilizer 9 and the downstream end of the central liquid fuel supply conduit 22 is substantially in the plane defined by the organs that form screen 11.

On the other hand, in order not to increase the loss of burner load before and after renovation, this is preferably done so that the section of air passage between the flame stabilizer 9 and the inner wall of the central feeding tube of Air 3 does not change substantially. In the present embodiment, by advancing the flame stabilizer 9 of the neck 203 to substantially the downstream end of the divergent section 201, this passage section has increased. Accordingly, the divergent section 201 is modified by reducing the opening made in the wall 4 (adding refractory materials 202). On the other hand,

In order to take into account the presence of the organs that form a screen 11 in certain angular sectors only in the present embodiment, the internal wall of the central air supply tube 3 is not angularly regular: in the sectors where the organs which form a screen are present, this wall is cylindrical and in the other angular sectors slightly conical divergent.

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The present invention is not limited to the embodiments given by way of examples. In this way, it will be possible to combine these different embodiments with each other.

It is equally possible, when the burner includes smoke circulation ducts, to have a ring that extends into the central air supply duct beyond the circle it has and that passes through the axes of the circulation ducts of smoke, even beyond the tangent circle to these smoke circulation tubes.

In parallel, in the case of a burner without a smoke circulation duct, it is possible that each screen-forming organ 15 extends around the external wall of the corresponding fuel gas supply tube over a distance greater than the diameter of the feed pipe combustible gas, even greater than twice this diameter. Likewise, the ring could extend from the central air supply tube into the central supply duct over a distance greater than twice the diameter of the fuel gas supply tube (even greater than three times this diameter).

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Claims (25)

5 10 fifteen twenty 25 30 35 40 Four. Five fifty 55 60 65 1. Gas fuel burner (1) comprising, on the one hand, a central air supply duct (2) that flows into a home and is delimited by a central air supply tube (3) around which it extends a wall (4) delimiting the home from outside and, on the other hand, fuel gas supply devices (5) that are arranged in the central air supply duct (2) and flow directly into the home, each comprising fuel gas feed device (5) a fuel gas feed duct (6) delimited by a fuel gas feed pipe (7) whose downstream end carries an injection nozzle (8), the burner (1) comprising screen-forming organs (11) partially obstructing the central air supply duct (2), each screen-forming organ extending (11) according to a plane parallel to the general plane of the opening downstream of the central duct to that of air supply (2), at the height of the downstream end of the corresponding fuel gas feeding device (5), characterized in that the set of screen forming organs (11) forms a ring that extends radially from the inner wall of the central air supply tube (3), over 360 °, to deplete the area where the combustible gas enters the home with oxygen. 2. Burner (1) according to claim 1, characterized in that each fuel gas supply device (5) is constituted by the fuel gas supply conduit (6) and by an annexed enclosure (100) which is delimited by a annex tube (101) extending parallel to the fuel gas supply line (6), in which this line (6) is arranged, whose upstream end is obstructed by a plate (20) crossed by the supply line of combustible gas (6) and whose downstream end flows directly into the home. 3. Burner (1) according to claim 2, characterized in that each screen-forming organ (11) extends from the external wall of the corresponding annex tube (101). 4. Gas fuel burner (1) comprising, on the one hand, a central air supply duct (2) that flows into a home and is delimited by a central air supply tube (3) around which it extends a wall (4) delimiting the home from outside and, on the other hand, fuel gas supply devices (5) that are arranged in the central air supply duct (2) and flow directly into the home, each being fuel gas supply device (5) consisting, on the one hand, of a fuel gas supply line (6) that is delimited by a fuel gas supply tube (7) whose downstream end has an injection nozzle ( 8) and, on the other hand, by an annexed enclosure (100) that is delimited by an annexed tube (101) extending parallel to the fuel gas supply line (6), in which this line (6) is arranged , whose upstream end is obstructed by a plate (20) crossed by the fuel gas supply line (6) and whose downstream end flows directly into the home, the burner (1) comprising screen-forming organs (11) partially obstructing the central duct of air supply (2), each screen-forming organ (11) extending according to a plane parallel to the general plane of the opening downstream of the central air supply duct (2), at the height of the downstream end of the device for corresponding fuel gas supply (5), characterized in that each screen-forming organ (11) extends from the external wall of the corresponding annex tube (101), over 360 °, to deplete oxygen the area in which the combustible gas penetrates the home 5. Burner (1) according to claim 4, characterized in that each screen-forming organ (11) extends radially from the inner wall of the central air supply tube (3). 6. Burner (1) according to claim 5, characterized in that the set of screen forming organs (11) forms a ring that extends over 360 ° around the inner wall of the central air supply tube (3). 7. Burner (1) according to one of claims 2, 3 or 6, characterized in that the ring extends into the central air supply duct (2) at least to the circle whose center is the axis (10 ) of the central air supply duct (2) and passing through the axes (15) of the enclosures (100). 8. Burner (1) according to claim 7, characterized in that the ring extends into the central air supply duct (2) at least to the circle whose center is the axis (10) of the central feeding duct of air (2) and tangent to the attached tubes (101). 9. Burner (1) according to one of claims 2 to 8, characterized in that the attached tubes (101) are tangent to the inner wall of the central air supply tube (3). 10. Burner (1) according to one of claims 2 to 9, characterized in that the annexed enclosure (100) comprises a smoke circulation duct (12) extending axially from the plane defined by the wall (4) delimiting the home from outside to the downstream end of the enclosure annex (100) and into which the injection nozzle (8) ends, the corresponding portion of the annex tube (101) forming a smoke circulation tube (13) in 5 10 fifteen twenty 25 30 35 40 Four. Five fifty 55 60 which is made a side smoke intake opening (14) turned angularly outwards of the central air supply tube (3). 11. Burner (1) according to claim 10 dependent on claim 9, characterized in that the lateral smoke intake opening (14) extends angularly over the portion of the smoke circulation tube (13) tangent to the inner wall of the central air supply tube (3), over the entire length of the smoke circulation tube (13). 12. Burner (1) according to one of claims 2 to 11, characterized in that the annexed enclosure (100) comprises a cavity (102) extending axially from the upstream end of the annexed enclosure (100) to the plane defined by the wall (4) delimiting the home from the outside, the corresponding portion of the attached tube (101) forming an upstream tube (103). 13. Burner (1) according to one of claims 2 to 12, characterized in that the axis (15) of each annexed enclosure (100) is the axis (16) of the corresponding fuel gas supply line (6). 14. Burner (1) according to one of claims 2 to 12, characterized in that the fuel gas supply tubes (7) are tangent to the inner wall of the attached tube (101). 15. Burner (1) according to one of claims 2 to 14, characterized in that each plate (20) comprises an opening (104) through which a smoke supply duct (105) flows through which fumes are introduced which They come from home and are recycled outside the latter. 16. Burner (1) according to claim 1, characterized in that each fuel gas supply device (5) is constituted by the fuel gas supply line (6) whose injection nozzle (8) flows directly into the home and which appears substantially in the plane defined by the wall (4) that delimits the exterior home. 17. Burner (1) according to claim 16, characterized in that the fuel gas supply tubes (7) are tangent to the inner wall of the central air supply tube (3). 18. Burner (1) according to claim 16 or 17, characterized in that each screen-forming organ (11) extends from the external wall of the corresponding fuel gas supply tube (7). 19. Burner (1) according to claim 18, characterized in that each screen-forming organ (11) extends over 360 ° around the external wall of the corresponding fuel gas supply tube (7) over a distance at least equal to diameter of the fuel gas supply tube (7). 20. Burner (1) according to one of claims 16 to 19, characterized in that the ring extends into the central air supply duct (2) at least to the circle centered on the axis of the central supply duct of air (2) and that is far from the wall of the central air supply tube (3) in a length equal to twice the diameter of the fuel gas supply tube (7). 21. Burner (1) according to one of claims 1 to 20, characterized in that the free radial edges (18) of each screen-forming organ (11) have a protective wall (19) that extends longitudinally along the axis. (10) of the central air supply duct (2), on both sides of the screen-forming organ (11). 22. Burner (1) according to claim 21, characterized in that the protective wall (19) is inclined at approximately 5 ° with respect to the axis (10) of the central air supply duct (2) to make the passage section convergent from air. 23. Burner (1) according to one of claims 1 to 22, characterized in that it comprises a flame stabilizing device (9) disposed on the shaft (10) of the central air supply duct (2), which extends radially to leave a free passage between its external radial flange (17) and the free radial edges (18) of the screen forming organs (11). 24. Burner (1) according to claim 23, characterized in that the plane of the downstream end of the flame stabilizing device (9) is that in which the screen forming organs (11) extend. 25. Burner (1) according to claim 23 dependent on claim 21 or 22, characterized in that the plane of the downstream end of the flame stabilizing device (9) is located between the two planes defined by the axial ends of the protective wall (19).