EP0006774A2 - Liquid fuel burner - Google Patents

Abstract

The burner is provided with a hollow vaporizing body, with a combustion initiating means, with heating means for starting up and with means for applying a method of burning, comprising the distinct and successive three phases: (a) vaporization of the liquid fuel protected from the flame, (b) mixing of the vaporized fuel obtained in phase (a), with a combustion supporter such as air, in a special chamber, protected from the flame, (c) combustion of the mixture obtained from phase (b), in a suitable zone, separate from the vaporizing and mixing zones.

Description

The invention relates to a method of combustion of a liquid fuel as well as a burner for its implementation and more particularly still, a self-cleaning combustion head with integral combustion.

According to a well-known principle of a burner, the liquid fuel is atomized by means of a nozzle, then mixed with air in a combustion head, before burning in a yellowish flame. A system based on this technique requires, for the combustion to be good, that the flame occurs in a sufficiently large space, so that all the particles of atomized fuel have time to burn. In fact, if the hearth where this form of combustion occurs is too small, the non-consumed liquid particles are projected onto the walls which, at too low a temperature, cause condensation and some pollution (soot, tar, etc.); it follows that the combustion efficiency and the heat exchange coefficient of the exchanger decrease by the insulation caused by the soot film which is interposed between the flame and the wall of the hearth. In addition, the minimum flow rate of the sprinklers is limited.

One of the aims of the invention is to reduce the volume of the combustion gases, thereby allowing the dimensions of the exchanger of the heating appliances, and in particular of the fireplace, to be reduced. Indeed, combustion in the presence of a blue flame, at very high temperature, as caused by the apparatus described in the present invention, makes it possible to reduce the combustion chamber by at least 90%, and consequently to reduce the weight and therefore the cost price of the devices in a high proportion.

The reduction in the volume of the exchangers makes it possible to reduce the usual dimensions of domestic or industrial boilers, which results in considerable financial gain, the boiler room or the place in which the device is placed being of reduced space.

According to another known principle of a burner, the liquid fuel is gasified, for example in a pot, and then burns, mixed with air, in the form of a yellow flame, sometimes blue, according to the method adopted. This form of combustion has the disadvantage of being

difficult to control, depending on the draft of the chimney, and generally requires an excess of air, which reduces the efficiency.

In another known burner principle, combustion takes place according to the two types of burner mentioned above. Thus, at the start, the combustion takes place in the atomized form of the liquid fuel, by spraying, by means of a cup or a rotary bell, the fuel then being gasified by heating of the said bell or cup. This generally results in combustion by blue flame. Devices based on this principle have many drawbacks, mainly due to the balance and wear of the moving parts and their fouling.

Another object of the invention is to allow perfect combustion of a liquid fuel, whatever the desired power, very low (less than 1 liter per hour) or very high (several tens of liters per hour), without the presence spraying devices, such as a sprinkler or a rotating cup. In addition, such combustion, for example in the form of an absolutely blue flame, depending on the type of fuel used, avoids any pollution of the atmosphere.

The combustion of a liquid fuel, as it occurs in conventional systems, takes place according to a process during which the transformation from the liquid state to the gaseous state, more or less well mixed with the air of combustion takes place within the flame. Indeed, a usual spray burner head does not allow an intimate pre-mixing of air and gasified fuel, since the gasification takes place by explosion of micro-drops of atomized liquid fuel, explosion caused by the temperature prevailing in the flame. This is how the flame is yellow and very eventful.

It has also been imagined to entrain a liquid fuel by the oxidizing air itself, so as to obtain at the same time, a vaporization of said fuel and the mixing of the latter with the oxidant. This method of proceeding has drawbacks, _' ' due in particular to the absence of premixing of the vaporized fuel and of the combustion air. The inventor has in fact found that in order to obtain good combustion, it is necessary to comply with certain conditions and to establish a cycle in three phases.

In a first phase, it involves performing a gasification or vaporization of the liquid fuel, away from the flame. Then, in a second phase, it is imperative to mix the vaporized fuel with an oxidizer such as air, in a special chamber and still sheltered from the flame, so as to obtain a stoichiometric mixture. Finally, in a third phase, the mixture thus obtained is burned, in an appropriate zone, separate from the vaporization and mixing zones.

In addition, it is particularly advantageous to carry out the vaporization in a duct or channel heated by the combustion flame and in which the fuel is conveyed by a carrier fluid, oxidizing or not, so as to allow a film vaporization of the liquid fuel and carbonization by pyrolysis of the bodies which cannot be vaporized in the said conduit or channel, which opens into the mixing chamber, where a stoichiometric mixture of the vaporized fuel and of the oxidant takes place. This process makes it possible in particular to reduce the size of the spraying element, and allows long and lasting operation by self-cleaning.

The film spraying makes it possible, in fact, to avoid any contact between the wall of the spraying element and the liquid to be vaporized, which avoids any possible fouling of this element, while carbonization by pyrolysis, which consists in bringing to high temperature certain parts of the burner, eliminates particularly dense and fatty, non-vaporizable elements. The film vaporization is in fact a caléfaction, maintained in an appropriate device, if we consider that the caléfaction is the physical process of vaporization of a drop of liquid, by a wall, at high temperature, this drop not being in contact with said wall, due to the existence of a vapor film, emitted from the drop itself, under the effect of the thermal energy transmitted by the wall.

To implement this process, the inventor proposes a burner for all liquid fuels, provided with a hollow vaporization body, with a means of initiating combustion and with means of heating for starting, remarkable in that it comprises a fixed body, provided with a tubular vaporization duct or duct, in which is conveyed, by an oxidizing vector fluid or not, a liquid fuel of, the said channel or conduit opening directly or not, in a mixing chamber, distinct from the said channel and which also receives an oxidizer, the heating means being arranged to heat the fixed body at start-up, while the shape of the said body is such that the combustion flame licks it in part, so that the liquid fuel is vaporized or gasified away from the flame, at least in part, and preferably entirely, in the channel or conduit vaporization. The liquid fuel feeds the burner through an intake pipe, opening into the vaporization channel or conduit, while the carrier fluid, for example in the form of gas, air, vapor or water, is introduced into the said fuel vaporization channel or conduit, in the vicinity of said intake pipe.

Such a device makes it possible in particular to obtain a film vaporization and a carbonization of the fatty elements, by pyrolysis, thereby avoiding any risk of fouling.

In addition, the elimination of the nozzle for atomizing the fuel as well as moving parts, means that the above-mentioned fixed combustion head has very interesting mechanical reliability, in particular in the case of use in a small domestic appliance. .

A burner according to the invention makes it possible to equip boilers and generators, the design of which is particularly studied to receive a blue flame, at high temperature.

Advantageously, the conduit in which the fuel is conveyed, consists of a tubular coil embedded, for example by overmolding, in the body of the burner. In addition, the mixing chamber preferably consists, at least in part, of the body, in such a way that it is continuously heated during combustion.

According to one embodiment, a thermostat with a change-over contact is provided for stopping at the desired temperature, the starting heating means, in the form for example of a heating resistance and causing on the one hand, the arrival of the liquid fuel. and of the carrier agent, in the vaporization conduit, and on the other hand, the actuation of the combustion initiation means, in the form for example of an electrode, controlled by means of a box regulator and transformer.

The body may have a substantially annular shape, preferably flared towards the outside, while a combustion grate or flame holder is arranged in the central part, so that the flame has a central position and licks the said body. from the inside.

In this case, the mixing chamber is preferably constituted, at least in part, by the body, which for this purpose has in its central part a form of bowl, in which the oxidant enters through one or more openings formed in it. this.

Advantageously, a final mixing chamber is arranged between the combustion grate or flame holder and the mixing chamber, by means of a separator constituted by a plate, provided with a central duct which plunges into the mixing chamber.

In the latter case, according to a preferred embodiment, the mixing chamber has a central oxidant inlet orifice, arranged in the lower wall thereof and provided with a flange with converging walls directed towards the separator duct and substantially coaxially, said duct having a shape or divergent walls.

Another embodiment is remarkable, in that the body has a substantially frustoconical shape, with a central heating means at start-up, while the combustion grate is arranged around said body, so that the annular flame licks the says body from the outside.

In this case advantageously, the mixing chamber is made in two parts, a first part arranged in the upper part of the body and into which the vaporization duct opens and a second part, arranged in the lower part of the body and into which the oxidizer, the two parts of the chamber communicating through orifices made in the body, around the heating means, while an annular chamber of final mixture is provided under the combustion grate and communicates with the second part mentioned above of the bedroom. i

For these various embodiments, a casing is fixed under the mixing chamber and has an orifice, for letting pass the intake pipe of the liquid fuel, an orifice for the agent tor and an orifice for the oxidizer, thereby constituting a preheating chamber.

Preferably, the carrier agent and the oxidizer are air, a single orifice in the casing then being provided for this air, which goes partly into the vaporization duct and partly into the mixing chamber.

It is clear, however, that the device according to the invention makes it possible to use another vector agent, as has already been said, the mixing with the oxidizing air taking place in the chamber provided for this purpose.

The above-mentioned embodiments make it possible to choose, at the same flame power, a short flame shape, covering a large area or, on the contrary, a very concentrated and longer flame, depending on the type of boiler or generator. to equip.

The new burners for liquid fuel according to the invention will also be able to equip a new generation of heaters and heat pump exchangers, having a liquid fuel as additional energy, instead of electricity. It is also possible to imagine small domestic heaters, operating by suction cup, thus avoiding the traditional chimney, since the combustion gases can be directly discharged into the atmosphere.

It is obvious that the use of various materials and different geometries for the hollow body can be imagined, without setting the framework of the invention.

• -la figure 1 est une vue en coupe d'un mode de réalisation d'un brûleur selon l'invention à flamme centrale ;
• -la figure 2 est une vue partielle de dessus, du brûleur de la figure 1 ;
• -la figure 3 est une vue en coupe, d'un autre mode de réalisation à flamme annulaire ; _`
• -la figure 4 est une vue de dessus, du brûleur de la figure 3 ;
• -la figure 5 est une vue partielle du brûleur de la figure 1, dont la chambre de mélange est modifiée.

The invention will be better understood and other particularities will appear on reading the description which follows and which refers to the attached drawing, in which:

• FIG. 1 is a sectional view of an embodiment of a burner according to the invention with a central flame;
• FIG 2 is a partial top view of the burner of Figure 1;
• FIG. 3 is a sectional view of another embodiment with an annular flame; _``
• FIG 4 is a top view of the burner of Figure 3;
• FIG. 5 is a partial view of the burner of FIG. 1, the mixing chamber of which is modified.

The main figures 1, 3 and 5 represent three embodiments according to the invention. In the numbering of each element, the first digit indicates the number of the main figure in which it is represented. For ease of understanding, the digit or digits following the first digit of each reference are identical when it comes to designating elements or bodies having similar or similar functions.

The burner according to the invention comprises a molded body 18, 38, 58 made of metal, alloy or other material, resistant to high temperatures. This body is provided with a vaporization duct 12, 32, 52 generally constituted by a molded tubular coil, the inlet and outlet ends of which are referenced respectively by 13, 33 and 19, 39, 59. An electrical resistance of annular preheating 17, or in the form of a central bar 37, is embedded in the body of the burner. An intake pipe 14, 34, for the liquid fuel, is arranged at the entrance to the vaporization duct.

The conduit 12, 32, 52 opens in 19, 39, 59, in a mixing chamber 111, 311, 511, formed in part by the body, while another final mixing chamber 113, 313, 513, before combustion , is provided under a combustion grate or flame holder 115, 315, 515.

A casing 118, 318, 518, disposed under the mixing chamber, determines a preheating chamber 16, 36, 56, provided with an air inlet orifice 15, 35.

An ignition or combustion ignition electrode 119 and an ionization flame control electrode 120 (not shown in FIGS. 3 and 5) are fixed in the body 18 by means of locking screws, screwed into suitable orifices 112, while a thermostat (not shown) with reversing contact is arranged under the said body, for example.

Figures 1, 2 and 5 show embodiments, in which the body 18, 58 has a substantially annular shape, flared outwards, while the mixing chamber 111, 511 is constituted by said body, which has for this purpose, in its central part, a bowl shape. In these two embodiments, the final mixing chamber 113, 513 is determined by a combustion grate or flame holder 115, 515 and a separator 117, 517, provided with a duct in the form of a central well, which plunges into said mixing chamber 111,511. The combustion grate 115 is held by means of a screw 116, which passes through the separator duct 117 and which is screwed into the part of the body constituting the lower wall of the mixing chamber 111, while the grate 515 of FIG. 5 is fixed by a screw 518 'screwed into the housing 518.

The mixing chamber 111 (FIG. 1) is provided with a plurality of peripheral orifices 110, which are preferably slightly inclined relative to a radial position. On the contrary, in the embodiment of FIG. 5, the body 58, in the part constituting the mixing chamber 511, is provided with a central orifice 510, provided with a flange 527 with converging walls and arranged in a substantially manner coaxial with the conduit of the separator 517, the latter having a divergent shape or walls.

The combustion grate 115 is provided with a plurality of slots 114, arranged radially, while the grate 515, disposed above the separator 517, forms an annular slot 514. The combustion grate 515 is provided with a tubular element central which fits into the separator duct 517 and which is provided with a plurality of orifices 532 for communication between the chambers 511 and 513.

The embodiment of FIG. 3 shows a substantially frustoconical body 38, provided with a central heating resistor 37, already mentioned, in the form of a bar. In this embodiment, the mixing chamber has two parts, 31la and 311b, arranged respectively above and below the resistor 37. The part 311a of the mixing chamber is hollowed out directly in the upper part of the body 38 and closed by a cover 326, while the part 311b is hollowed out in the lower part of the said body and closed by a seal 322, made of insulating material, disposed between the body 38 and the casing 318, so that the pre-chamber -heating 36 is located just below and that the orifices 310 are formed in the said seal opposite the air inlet orifice 35.

The part 311a, into which the vaporization conduit 32 opens at 39, communicates with the part 311b, receiving the com running through conduits 323.

The annular combustion grate 315, provided with slots 314, is arranged around the body 38. The part 311b of the mixing chamber communicates with the final mixing chamber 313 by tangential outlet channels 325, while a ring 321 is fitted on the joint 322, in the final mixing chamber 313.

The embodiments being described in their constitution, the operation appears clearly.

The electrical resistance 17, 37 is firstly energized. When a sufficient temperature is reached (of the order of 250 to 280 ° C.) a thermostat (not shown) with reversing contact, cuts the said resistance and simultaneously allows the arrival of the liquid fuel through the intake pipe 14, 34 and the air inlet through the orifice 15, 35.

This thermostat, suitably placed under the body 18, 38, 58 for example, causes at the same time and by means of a regulating box and a transformer, electric arcs at the level of the ignition electrode 119 .

In this way, the liquid fuel arrives at the inlet 13, 33 of the conduit 12, 32, 52 through the intake pipe 14, 34, at the same time as the air which comes from the chamber 16, 36, 56 supplied by 15, 35.

The liquid fuel thus conveyed in line 12, 32, 52 vaporizes immediately and reaches the mixing chamber 111, 311, 511.

In the latter, the vaporized fuel mixes intimately with the combustion air which arrives through the orifices 110, 310, 510 after having been heated in the preheating chamber 16, 36, 56. The mixing is facilitated in the mode of embodiment of FIG. 1, by the tangential inclination of the orifices 110, which causes a circular movement of the gases.

The oxidizing air and the vaporized fuel then flow into the final mixing chamber 113, 313, 513. In the embodiments of FIGS. 1 and 5, the mixture obtained passes through the conduit. central of the separator 117, 517. Advantageously, in the embodiment of FIG. 5, the converging walls of the edge of the orifice 510 and the diverging walls of the central duct of the separator 517, constitute a divergent convergent which has the effect of appreciably improving the circulation of the fuel in the vaporization duct.

In the embodiment of FIG. 3, the vaporized fuel arrives in part 311a and mixes with the combustion air in part 311b, while the channels with tangential outlets allow a vortex mixture of the gases in chamber 313, while that the ring 321 results in good homogeneity of the said gases.

The mixture obtained in chamber 113, 313, 513 escapes through the grid 115, 315, 515 and ignites instantly by means of the electrode 119, while the electrode 120 controls the flame by ionization and makes it possible to immediately stop supplying the ignition transformer if there is no flame. This flame control can also be obtained by means of an ionization cell, if desired.

The molded body 18, 38, 58 is thus heated by the flame resulting from the combustion of the combustible mixture which leaves through the slots 114, 314, 514, with a sufficient speed to prevent combustion from forming under the grate 115, 315 , 515. In this regard, it is interesting to note that, in order to obtain a gas ejection speed, greater than the flame propagation speed, the communication section of the separator 117, 517, constituted by its central duct, in the embodiments of FIGS. 1 and 5, must represent an area in relation to the total area of the slots 114 and 514.

The shape of the molded body 18, 38, 58, which represents a surface 11, 31, 51, in contact with the flame determines the shape of said flame, which can be inside (Figures 1, 2 and 5) or outside (Figures 3 and 4) of said body, that is to say having a central or annular position.

The body 18, 38, 58 allows thermal conduction between the resistor 17, 37 and the tubular coil constituting the vaporizing conduit, and at the same time between the flame and the said coil which is lost at high temperature.

In the embodiments shown, the fuel which undergoes a film vaporization, is transported by air, which serves as a carrier. However, it is possible to use another carrier separate from the combustion air, as it would be possible, to bring the entire combustion air through the inlet of the vaporization duct.

However, the last mentioned case, which eliminates the need to provide orifices 110, 310 and 510, has certain drawbacks. It is in fact then necessary to have a larger contact surface 11, 31, 51 in order to heat a larger volume of air to maximum temperature. It is also necessary to provide a vaporization duct with a larger section (and therefore a more bulky burner) to allow the same air flow at the inlet 15, 35, or, with the same duct section, or therefore for the same power, to have a higher air pressure at said inlet. In addition, in this case there would no longer be a combustion process with a distinct mixing phase, as recommended by the invention.

• a) une combustion parfaite et anti-polluante,
• b) un très haut rendement de combustion (économie d'énergie)
• c) une simplicité de réalisation (faible prix de revient)
• d) un fonctionnement absolument silencieux,
• e) un faible volume en rapport avec la puissance désirée,
• f) un auto-nettoyage par pyrolise,
• g) une conception qui permet une fabrication de série,
• h) la conception de nouvelles techniques de chaudières et échangeurs,
• i) un volume des gaz de combustion réduit pour une même puissance et donc une réduction du volume des foyers des appareils de chauffage,
• j) une combustion totalement achevée dans la flamme bleue et donc sans risque d'imbrûlés,
• k) une obtention de 15,2 % de CO 2 pour la combustion du fuel oil domestique (c'est à dire le maximum possible),
• 1) aucune pièce en mouvement et donc pas d'usure mécanique,
• m) la possibilité d'avoir de très petits débits (inférieurs à 1 litre/h) sansrisque d'obstruction, par suite de l'absence de gicleur de pulvérisation, ¹
• n) en petite puissance, la possibilité d'évâcuer directement à l'extérieur et sans cheminée, les gaz de combustion (système à ventouse),
• o) une économie dans les coûts de construction et d'exploitation, due à l'absence du conduit de cheminée de chaufferie.

The invention which has just been described makes it possible to obtain combustion, the advantages of which are numerous and more particularly:

• a) perfect and anti-polluting combustion,
• b) very high combustion efficiency (energy saving)
• c) simplicity of implementation (low cost price)
• d) absolutely silent operation,
• e) a small volume in relation to the desired power,
• f) self-cleaning by pyrolysis,
• g) a design which allows mass production,
• h) the design of new boiler and exchanger techniques,
• i) a reduced volume of combustion gases for the same power and therefore a reduction in the volume of the homes of the heating appliances,
• j) combustion completely completed in the blue flame and therefore without risk of unburnt,
• k) obtaining 15.2% CO 2 for the combustion of domestic fuel oil (that is to say the maximum possible),
• 1) no moving parts and therefore no mechanical wear,
• m) the possibility of having very small flow rates (less than 1 liter / h) without risk of obstruction, due to the absence of spray nozzle, ¹
• n) at low power, the possibility of venting directly to the outside and without a chimney, the combustion gases (suction system),
• o) savings in construction and operating costs due to the absence of the boiler chimney flue.

Many modifications or variations can be imagined, without departing from the scope of the invention. Thus, for example, the vaporization duct may not be provided with an overmolded coil, the carrier may be something other than air, the casing 118, 318, 518 may be removed, etc. . In addition, the trusses of the body and of the combustion grates can be different, as well as the shape of the slots of the said grates, constituted for example by circular orifices or otherwise.

The main object of the invention is to provide a good combustion process and a burner as described above, in which the vaporization duct or channel is arranged in the fixed body, so as to be sufficiently heated by the flame, but protected from it, so as to allow a film vaporization of the liquid fuel conveyed by the carrier fluid through said channel or conduit, while the mixing chamber makes it possible to obtain a mixture in stoichiometric proportion, at protected from flame, previously vaporized fuel and oxidizer.

Claims (15)

1) Method of combustion of a liquid fuel, characterized in that it comprises the following three distinct and successive phases: a) vaporization of the liquid fuel away from the flame, b) mixing the vaporized fuel obtained in phase a) with an oxidizer such as air, in a special chamber protected from the flame, c) combustion of the mixture obtained in phase b), in an appropriate zone, separate from the vaporization and mixing zones. 2) Combustion method according to claim 1, characterized in that it consists in carrying out the vaporization phase a) in a duct or channel heated by the combustion flame and in which the fuel is conveyed by a vector, oxidizing or no, so as to allow film vaporization of the liquid fuel and carbonization by pyrolysis, of the non-vaporizable bodies, in the said conduit or channel, which opens into the mixing chamber, where a stoichiometric mixture of the vaporized fuel and the oxidizer. 3) Burner for liquid fuels, intended for the implementation of the method according to one of claims 1 and 2 and provided with a hollow vaporization body, a means of initiating combustion and heating means for start-up, characterized in that it comprises a fixed body (18, 38, 58), provided with a tubular vaporization duct or duct (12, 32, 52), in which is conveyed by a carrier, oxidizing or no, a liquid fuel, the so-called uu conduic channel opening, directly or not, in a mixing chamber (111, 311, 511) distinct from the said channel and which also receives an oxidizer, the heating means (17, 37) being arranged to heat the fixed body at start-up, while the shape of said body is such that the combustion flame licks the latter in part, such that the liquid fuel is vaporized or gasified away from the flame, at least partly and preferably entirely, in the vaporization channel or conduit. 4) Burner according to claim 3, characterized in that the fuel feeds the burner by an intake pipe (14, 34) outlet edge in the vaporization channel or tubular conduit (12, 32,52), while the carrier fluid, for example in the form of gas, air, vapor or water, is introduced into said channel or conduit fuel vaporization, in the vicinity of the intake pipe. 5) Burner according to one of claims 3 and 4, characterized in that the conduit in which the fuel is conveyed consists of a tubular coil embedded, for example by overmolding, in the body of the burner. 6) Burner according to any one of claims 3 to 5, characterized in that the mixing chamber (111, 311, 511) is formed at least in part by the body, so that it is continuously heated , during combustion. 7) Burner according to any one of claims 3 to 6, characterized in that a reversing contact thermostat is provided for stopping, at the desired temperature, the starting heating means, for example in the form of a resistance heating (17, 37) and cause, on the one hand, the arrival of the liquid fuel and the carrier agent in the vaporization duct (12, 32, 52), and on the other hand, the aeration of the means initiating combustion, in the form, for example, of an electrode controlled by means of a regulation box and a transformer. 8) Burner according to any one of claims 3 to 7, characterized in that the body has a sensibl shape: -ment annular (18, 58), preferably flared outward, while a combustion grate or a flame catch (115, 515) is arranged in the central part, so that the flame has a central position and licks the said body from the inside. 9) Burner according to claim 8, characterized in that the mixing chamber (111, 511) is constituted at least in part by the body, which has for this purpose, in its central part., A bowl shape, in which between the oxidizer by one or more openings (110, 510) formed therein. 10) Burner according to claim 9, characterized in that a final mixing chamber (113, 513) is arranged between the combustion grate or flame holder and the mixing chamber, by means of a separator (117, 517 ) consisting of a plate fitted with a cen duct tral which plunges into the mixing chamber. 11) Burner according to claim 10, characterized in that the mixing chamber has a central orifice (510) for admitting the oxidant, arranged in the lower wall thereof and provided with a flange (527) with converging walls , directed towards the separator duct and in a substantially coaxial manner, said duct having a divergent shape or walls. 12) Burner according to any one of claims 3 to 7, characterized in that the body provided with the channel or vaporization duct has a substantially frustoconical shape (38) with a central heating means at start-up (37), while the combustion grate (315) is arranged around said body, so that the annular flame licks said body from the outside. 13) Burner according to claim 12, characterized in that the mixing chamber (311) is made in two parts, a first part (311a) arranged in the upper part of the body and into which opens the vaporization conduit (32) and a second part (311b) arranged in the lower part of the body and into which the oxidant arrives, the two parts of the chamber communicating through orifices (323) formed in the body around the heating means (37), while a annular chamber (313) of final mixture is provided under the combustion grate (315) and communicates with the second part (311b) mentioned above of the chamber. 14) Burner according to any one of claims 3 to 13, characterized in that a casing (118, 318, 518) is fixed under the mixing chamber and has an orifice for allowing the intake pipe (14, 34) liquid fuel, an orifice for the carrier and an orifice for the oxidant, thereby constituting a preheating chamber (16, 36, 56). 15) Burner according to claim 14, characterized in that the carrier agent and the oxidizer are air, a single orifice (15, 35) in the casing, then being provided for this air, which is directed in part the vaporization pipe and partly in the mixing chamber.

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