EP0730122B1 - Gas burner with improved acoustical attenuation - Google Patents

Gas burner with improved acoustical attenuation Download PDF

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Publication number
EP0730122B1
EP0730122B1 EP96400420A EP96400420A EP0730122B1 EP 0730122 B1 EP0730122 B1 EP 0730122B1 EP 96400420 A EP96400420 A EP 96400420A EP 96400420 A EP96400420 A EP 96400420A EP 0730122 B1 EP0730122 B1 EP 0730122B1
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EP
European Patent Office
Prior art keywords
tube
burner
length
venturi tube
inlet opening
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
EP96400420A
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German (de)
French (fr)
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EP0730122A1 (en
Inventor
Peter Wagstaff
Christian Chassaignon
Gwenaelle Schubert
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Chaffoteaux et Maury SAS
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Chaffoteaux et Maury SAS
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Publication of EP0730122A1 publication Critical patent/EP0730122A1/en
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Classifications

    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/175—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general using interference effects; Masking sound
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
    • F23D14/02—Premix gas burners, i.e. in which gaseous fuel is mixed with combustion air upstream of the combustion zone
    • F23D14/04—Premix gas burners, i.e. in which gaseous fuel is mixed with combustion air upstream of the combustion zone induction type, e.g. Bunsen burner
    • F23D14/10—Premix gas burners, i.e. in which gaseous fuel is mixed with combustion air upstream of the combustion zone induction type, e.g. Bunsen burner with elongated tubular burner head
    • F23D14/105—Premix gas burners, i.e. in which gaseous fuel is mixed with combustion air upstream of the combustion zone induction type, e.g. Bunsen burner with elongated tubular burner head with injector axis parallel to the burner head axis
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D14/00—Burners for combustion of a gas, e.g. of a gas stored under pressure as a liquid
    • F23D14/46—Details, e.g. noise reduction means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D2210/00—Noise abatement

Definitions

  • the present invention relates to burners with gases with improved acoustic discretion as described in the preamble of claim 1.
  • DE-A-22 63 471 describes an example of a like a gas burner.
  • the present invention aims to provide a burner with gas of the kind in question which does not have an entry forced air, but a venturi tube fitted with a gas and which is especially effective in mitigating noise generated by the operation of the gas injector and the venturi tube.
  • a gas burner of the genre in question is essentially characterized in that the interior volume includes a venturi tube having a upstream end which is provided with a gas injector combustible and which is shaped to draw air under the effect of fuel gas injection thereby generating the aforementioned noises, the space entrance opening anti-noise hollow communicating with the venturi tube and being disposed at a distance from the upstream end of the tube venturi which is between 0.2 k ⁇ and 0.3 k ⁇ , where k is an odd integer and where ⁇ is the wavelength predetermined.
  • reference 1 designates an atmospheric burner gas which is intended to be integrated in a boiler, in a water heater, in a bath heater or the like.
  • This burner 1 comprises a venturi tube 2 which extends between an inlet end 3 communicating with the atmosphere and an outlet end 4 communicating with a premix chamber 5, upstream of a combustion grate 6 or any other combustion head.
  • the bedroom premix 5 is delimited by a solid side wall, in general metallic and it communicates only with the venturi tube 2 and with combustion grate 6.
  • the venturi tube 2 conventionally comprises, from upstream to downstream, a short converging section, a pass, then a long divergent section, and it is provided at its inlet end 3 of a fuel gas injector 7.
  • the burner 1 has a single venturi tube 2, but it could have possibly several venturis tubes opening into the same premix chamber, without departing from the scope of the present invention.
  • the tube venturi 2 opens into the premix chamber 5 through the bottom 5a of this chamber, at a longitudinal end 5b of said chamber, and the venturi tube 2 is folded under the bottom 5a substantially parallel to the grid of combustion 6, towards the second longitudinal end 5b of the premix chamber.
  • venturi tube 2 could however be arranged differently from the premix chamber 5, and in particular, it could be arranged under the bottom 5a of the premix chamber substantially perpendicular to the combustion grate 6.
  • the noise barriers are generated by means of two resonant cavities in the form of tubes 10, called "quarter-wave" tubes. These tubes have a section of any shape and each extend longitudinally between on the one hand an open end 11 communicating with the inside of the venturi tube 2, and on the other hand a closed bottom 12.
  • the acoustic vibrations which take place inside the venturi tube 2 penetrate into each of the two tubes 10 through their open end 11, and these vibrations travel the longitudinal length, respectively l 1, l 2 of these tubes before being reflected on their bottom 12, then they again travel the longitudinal length of said tubes in the opposite direction before returning to the venturi tube 2.
  • the two tubes 10 generate counter-noises in phase opposition with the noises generated in the venturi tube 2 in the vicinity of two predetermined frequencies corresponding to wavelengths ⁇ 1 and ⁇ 2 such that the lengths l 1 and l 2 tubes are respectively substantially equal to a quarter of the wavelengths ⁇ 1 and ⁇ 2, or more generally equal to odd integer multiples of a quarter of the wavelengths ⁇ 1 and ⁇ 2.
  • the inlet ends 11 of the tubes 10 are arranged to communicate with an area of the internal volume of the burner where the acoustic vibrations having the frequency to be absorbed have an amplitude maximum.
  • the inlet ends 11 of the tubes 10 are preferably arranged at respective distances l 3, l 4 from the inlet end 3 of the venturi tube which are respectively substantially equal to odd integer multiples of a quarter of the lengths of waves ⁇ 1 and ⁇ 2 of the noises which are respectively muffled by the two tubes 10.
  • the distance l 3 can be between 0.2 k1 ⁇ 1 and 0.3 k1 ⁇ 1, and the distance l 4 can be between 0.2 k2 ⁇ 2 and 0.3 k2 ⁇ 2, where k1 and k2 are odd whole numbers, preferably equal to 1 or 3.
  • the distances between the input end 3 of the venturi tube and the inlets 11 of the tubes are curvilinear distances corresponding to the average path followed by the gases from the inlet end 3 of the tube venturi to the entry openings in question.
  • FIG. 2 shows a spectrum of acoustic vibrations measured in an exemplary embodiment particular of the burner 1 represented in FIG. 1, on the one hand without the two tubes 10 (in solid lines), and on the other hand with the two tubes 10 (dotted lines).
  • burner 1 could be provided of a single tube 10 or possibly of more than two tubes 10, depending on the desired noise frequencies absorb.
  • the tubes 10 could possibly communicate with the premix chamber 5 rather than with the venturi tube 2, they could if necessary present a straight rather than curvilinear shape such as that shown in Figure 1 and they might possibly not be arranged in the plane of symmetry of burner 1.
  • the tubes 10 are arranged with their longitudinal axes in the plane of symmetry of the burner 1, as shown in FIG. 1, insofar as this provision makes it possible to carry out simply burner 1 by stamping then assembly of two metal half-shells, one of these half-shells being shown schematically in Figure 1. Each half-shell then represents half of the venturi tube 2, of the side wall of the premix chamber 5, and of each tube 10.
  • the grid of combustion 6 will usually be reported above the premix chamber 5 after assembly of the two half-shells.
  • the tubes 10 could be replaced by one or more cavities resonant 20 having another form.
  • the resonant cavity 20 is in the form of a volume capacity V, called "Helmholtz resonator" designed to produce inside of the burner 1 against noise in phase opposition with noises presenting the frequency to be attenuated.
  • the resonant cavity 20 communicates with the interior of the venturi tube 2 or the premix chamber 5 via an entrance 21 and it is delimited by a wall waterproof 22.
  • the resonant cavity 20 can communicate with the venturi tube 2 or with the premix chamber 5, and one or more can be provided several resonant cavities depending on the number of frequencies to be attenuated.
  • the inlet 21 of the cavity 20 is preferably arranged in an area where the amplitude of the acoustic vibrations is maximum in the burner, for example at a distance l 5 from the upstream end 3 of the venturi tube which is between 0.2 and 0.3 times an odd integer multiple k of the wavelength ⁇ of the noise to be attenuated, k preferably being equal to 1 or 3.
  • the distance l 5 is preferably close to ⁇ / 4 or more generally close to an odd integer multiple k of ⁇ / 4, k being preferably equal to 1 or 3.
  • the resonant cavity 20 is preferably, but not exclusively, symmetrically arranged with respect to the plane of symmetry of the burner 1, so that the entire burner 1, except where applicable the grate combustion 6, can be achieved by stamping two metal half-shells assembled according to the plane of symmetry, as explained above with reference to FIG. 1.
  • the counter-noises are generated by means of a tube of link 30, of any section, which extends between a share an upstream end 31 or communicating entrance opening with the venturi tube 2, and on the other hand an end downstream 32 communicating with the venturi tube or the premix 5.
  • the ends of the tube 30 can optionally both communicate with the premix chamber 5.
  • the gas mixture which passes through the burner 1 without passing through the connection tube 30 travels a distance L in the venturi tube and the premix chamber 5 between the ends 31 and 32 of the tube of connection, and the connection tube has a length, respectively l 6, l 7, which is either less than or greater than the distance L and which differs from the distance L by a length n ⁇ / 2, where n is a number odd integer and where ⁇ is the wavelength of the noises to be suppressed.
  • n will most often be equal to 1.
  • the length l 6 of the connecting tube 30 is half a wavelength shorter than the length L, and in the example of FIG. 5, the length l 7 of the tube link 30 is half a wavelength longer than length L.
  • the connecting tube 30 Due to its length, the connecting tube 30 generates in any case at its end 32 a noise counter phase opposition with the acoustic vibrations of the gas mixture for the predetermined frequency to be damped.
  • the tube 30 is preferably, but not exclusively, arranged in the plane of symmetry of burner 1, so that this burner, except the if necessary its combustion grate 6, can be produced by stamping two metal half-shells then assembly of these two half-shells along the plane of symmetry.
  • the distance l 8 between the end 31 of the connection tube and the upstream end 3 of the venturi tube can be between 0.2 k ⁇ and 0.3 k ⁇ , this distance being advantageously close to k ⁇ / 4
  • the distance l 9 between the second end 32 of the connecting tube and the upstream end 3 of the venturi tube can be between 0.2 q ⁇ and 0.3 q ⁇ and advantageously close to q ⁇ / 4, where k and q are two different odd integers and where ⁇ is the wavelength of the noise to be attenuated (k is preferably equal to 1 or 3).
  • the counter-noises are generated by means of a resonant cavity annular 35 formed at the upstream end 3 of the tube venturi.
  • annular resonant cavity is delimited radially outwards by an annular wall outer 33 full which laterally delimits the tube venturi 2, and radially inward by a wall full annular 34 having successively a section converge, a pass, then a divergent section,
  • the wall 34 is in sealed peripheral contact with of the outer wall 33 upstream (the upstream ends of these two walls are not necessarily confused), and it extends downstream inside the outer wall 33 to an open end 34a which communicates with the inside of the wall 33.
  • annular resonant cavity 35 extends along the longitudinal axis of the venturi tube 2 between a upstream end 35a closed and a downstream end 35b which forms an annular opening constituting the entrance to the resonant cavity.
  • upstream and downstream ends are separated from each other by an axial distance l 10 substantially equal to a quarter of the wavelength of the noise to be suppressed, or more generally substantially equal to an odd multiple of a quarter. of this wavelength (preferably ⁇ / 4 or 3 ⁇ / 4), the distance between the inlet end 3 of the venturi tube and the inlet opening 35b of the resonant cavity being between 0.2 k ⁇ and 0.3 k ⁇ where k is an odd integer (preferably 1 or 3) and ⁇ is the wavelength of the noise to be attenuated.
  • the internal volume of the burner has, at right of the entrance opening of the noise-canceling hollow space (resonant cavity or connecting tube), a section of passage of the air-gas mixture which is at least 10 times more large than the section of said inlet opening, the cross section of the air-gas mixture being the section of the internal volume of the burner taken perpendicular to the average direction of gas flow.

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  • Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Gas Burners (AREA)
  • Fuel Cell (AREA)

Description

La présente invention est relative aux brûleurs à gaz présentant une discrétion acoustique améliorée tels que décrits dans le préambule de la revendication 1.The present invention relates to burners with gases with improved acoustic discretion as described in the preamble of claim 1.

Le document DE-A-22 63 471 décrit un exemple d'un tel brûleur à gaz.DE-A-22 63 471 describes an example of a like a gas burner.

La présente invention vise à proposer un brûleur à gaz du genre en question qui comporte non pas une entrée d'air pulsée, mais un tube venturi doté d'un injecteur de gaz et qui soit spécialement efficace pour atténuer les bruits générés par le fonctionnement de l'injecteur de gaz et du tube venturi.The present invention aims to provide a burner with gas of the kind in question which does not have an entry forced air, but a venturi tube fitted with a gas and which is especially effective in mitigating noise generated by the operation of the gas injector and the venturi tube.

A cet effet, selon l'invention, un brûleur à gaz du genre en question est essentiellement caractérisé en ce que le volume intérieur comprend un tube venturi présentant une extrémité d'amont qui est pourvue d'un injecteur de gaz combustible et qui est conformée pour aspirer de l'air sous l'effet de l'injection du gaz combustible en générant ainsi les bruits susmentionnés, l'ouverture d'entrée de l'espace creux antibruit communiquant avec le tube venturi et étant disposée à une distance de l'extrémité d'amont du tube venturi qui est comprise entre 0,2 k λ et 0,3 k λ, où k est un nombre entier impair et où λ est la longueur d'onde prédéterminée.To this end, according to the invention, a gas burner of the genre in question is essentially characterized in that the interior volume includes a venturi tube having a upstream end which is provided with a gas injector combustible and which is shaped to draw air under the effect of fuel gas injection thereby generating the aforementioned noises, the space entrance opening anti-noise hollow communicating with the venturi tube and being disposed at a distance from the upstream end of the tube venturi which is between 0.2 k λ and 0.3 k λ, where k is an odd integer and where λ is the wavelength predetermined.

Dans des modes de réalisation préférés, on a recours en outre à l'une et/ou à l'autre des dispositions suivantes :

  • le brûleur présente un plan de symétrie et comporte deux demi-coques embouties qui sont assemblées l'une à l'autre et qui délimitent chacune une moitié du volume intérieur du brûleur et de l'espace creux antibruit, ce qui permet une réalisation simple et peu coûteuse du brûleur ;
  • l'espace creux antibruit est une cavité résonante fermée qui communique avec le volume intérieur dudit brûleur uniquement par l'ouverture d'entrée ;
  • la cavité résonante est un tube résonant qui s'étend sur une certaine longueur entre l'ouverture d'entrée et une extrémité fermée, la longueur de ce tube résonant étant sensiblement égale à un multiple entier impair du quart de la longueur d'onde prédéterminée ;
  • le tube venturi présente vers son extrémité d'amont une paroi annulaire extérieure pleine qui entoure une paroi annulaire intérieure pleine en délimitant avec la paroi extérieure un volume annulaire qui forme la cavité résonante, cette cavité résonante s'étendant selon l'axe longitudinal du tube venturi entre d'une part une extrémité d'amont fermée voisine de l'extrémité d'amont du tube venturi et d'autre part une extrémité d'aval qui forme une ouverture annulaire constituant l'ouverture d'entrée de la cavité résonante ;
  • l'espace creux antibruit est un tube de liaison qui s'étend sur une certaine longueur entre des première et deuxième extrémités communiquant toutes les deux avec le volume intérieur dudit brûleur, la première extrémité du tube de liaison formant l'ouverture d'entrée susmentionnée, la deuxième extrémité étant située en aval de la première extrémité, l'air et le gaz combustible qui transitent dans le brûleur sans passer par le tube de liaison parcourant une longueur déterminée entre les deux extrémités du tube de liaison, et la longueur du tube de liaison différant de ladite longueur déterminée par une longueur n λ/2, où n est un nombre entier impair et où λ est la longueur d'onde prédéterminée ;
  • la longueur du tube de liaison est supérieure à la longueur déterminée parcourue entre les deux extrémités dudit tube de liaison par l'air et le gaz combustible qui transitent dans le brûleur sans passer par le tube de liaison ;
  • le tube venturi débouche dans une chambre de prémélange en amont de la tête de combustion, la chambre de prémélange s'étendant longitudinalement entre deux extrémités et communiquant avec le tube venturi à une seule de ses extrémités, le tube venturi étant disposé le long de la chambre de prémélange, et la longueur du tube de liaison étant inférieure à la longueur prédéterminée parcourue entre les deux extrémités dudit tube de liaison par l'air et le gaz combustible qui transitent dans le brûleur sans passer par le tube de liaison ;
  • la deuxième extrémité du tube de liaison communique avec le tube venturi, est disposée à une distance de l'extrémité d'amont du tube venturi qui est comprise entre 0,2 q λ et 0,3 q λ, où q est un nombre entier impair supérieur à k ;
  • k vaut 1 ou 3 ;
  • le volume intérieur du brûleur présente, au droit de l'ouverture d'entrée de l'espace creux antibruit, une section de passage du mélange air-gaz qui est au moins 10 fois plus grande que la section de ladite ouverture d'entrée : on évite ainsi l'émission par l'espace creux antibruit de bruits de fréquences supérieures qui pourraient éventuellement renforcer les bruits émis par le brûleur à des longueurs d'ondes différentes de la longueur d'onde λ que l'on cherche à atténuer.
In preferred embodiments, use is also made of one and / or the other of the following arrangements:
  • the burner has a plane of symmetry and comprises two stamped half-shells which are assembled to each other and which each delimit one half of the internal volume of the burner and the hollow noise reduction space, which allows a simple and inexpensive burner;
  • the anti-noise hollow space is a closed resonant cavity which communicates with the internal volume of said burner only through the inlet opening;
  • the resonant cavity is a resonant tube which extends over a certain length between the inlet opening and a closed end, the length of this resonant tube being substantially equal to an odd integer multiple of a quarter of the predetermined wavelength ;
  • the venturi tube has, towards its upstream end, a solid outer annular wall which surrounds a solid inner annular wall, delimiting with the outer wall an annular volume which forms the resonant cavity, this resonant cavity extending along the longitudinal axis of the tube venturi enters on the one hand a closed upstream end close to the upstream end of the venturi tube and on the other hand a downstream end which forms an annular opening constituting the entry opening of the resonant cavity;
  • the noise reduction hollow space is a connecting tube which extends over a certain length between first and second ends, both communicating with the internal volume of said burner, the first end of the connecting tube forming the aforementioned inlet opening , the second end being located downstream of the first end, the air and the combustible gas which pass through the burner without passing through the connection tube traversing a determined length between the two ends of the connection tube, and the length of the tube link differing from said length determined by a length n λ / 2, where n is an odd integer and where λ is the predetermined wavelength;
  • the length of the connecting tube is greater than the determined length traveled between the two ends of said connecting tube by the air and the combustible gas which pass through the burner without passing through the connecting tube;
  • the venturi tube opens into a premix chamber upstream of the combustion head, the premix chamber extending longitudinally between two ends and communicating with the venturi tube at only one of its ends, the venturi tube being disposed along the premix chamber, and the length of the connecting tube being less than the predetermined length traveled between the two ends of said connecting tube by the air and the combustible gas which pass through the burner without passing through the connecting tube;
  • the second end of the connecting tube communicates with the venturi tube, is disposed at a distance from the upstream end of the venturi tube which is between 0.2 q λ and 0.3 q λ, where q is an integer odd greater than k;
  • k is 1 or 3;
  • the internal volume of the burner has, at the level of the inlet opening of the noise-canceling hollow space, a cross section of the air-gas mixture which is at least 10 times larger than the section of said inlet opening: this avoids the emission by the noise-canceling hollow space of noises of higher frequencies which could possibly reinforce the noises emitted by the burner at wavelengths different from the wavelength λ which it is sought to attenuate.

D'autres caractéristiques et avantages de l'invention apparaítront au cours de la description détaillée suivante de plusieurs de ses formes de réalisation, données à titre d'exemples, en regard des dessins joints.Other characteristics and advantages of the invention will appear during the detailed description following of many of its embodiments given as examples, with reference to the drawings joints.

Sur les dessins :

  • la figure 1 est une vue schématique en coupe et en perspective montrant un brûleur atmosphérique à gaz selon une forme de réalisation de l'invention,
  • la figure 2 est un graphe montrant les améliorations apportées à la discrétion sonore d'un brûleur atmosphérique à gaz grâce aux dispositions représentées sur la figure 1,
  • les figures 3 à 5 sont des vues schématiques en coupe montrant des brûleurs atmosphériques à gaz selon trois autres formes de réalisation de l'invention,
  • et la figure 6 est une vue partielle similaire à la figure 1, montrant l'extrémité d'amont du tube venturi d'un brûleur selon encore une autre forme de réalisation de l'invention.
In the drawings:
  • FIG. 1 is a schematic sectional and perspective view showing an atmospheric gas burner according to one embodiment of the invention,
  • FIG. 2 is a graph showing the improvements made to the acoustic discretion of an atmospheric gas burner thanks to the arrangements represented in FIG. 1,
  • FIGS. 3 to 5 are schematic sectional views showing atmospheric gas burners according to three other embodiments of the invention,
  • and FIG. 6 is a partial view similar to FIG. 1, showing the upstream end of the venturi tube of a burner according to yet another embodiment of the invention.

Sur les différentes figures, les mêmes références désignent des éléments identiques ou similaires.In the different figures, the same references denote identical or similar elements.

Dans toutes les formes de réalisation considérées ci-dessous, la référence 1 désigne un brûleur atmosphérique à gaz qui est destiné à être intégré dans une chaudière, dans un chauffe-eau, dans un chauffe-bain ou similaire.In all the embodiments considered below, reference 1 designates an atmospheric burner gas which is intended to be integrated in a boiler, in a water heater, in a bath heater or the like.

Ce brûleur 1 comporte un tube venturi 2 qui s'étend entre une extrémité d'entrée 3 communiquant avec l'atmosphère et une extrémité de sortie 4 communiquant avec une chambre de prémélange 5, en amont d'une grille de combustion 6 ou de toute autre tête de combustion. La chambre de prémélange 5 est délimitée par une paroi latérale pleine, en général métallique et elle communique uniquement avec le tube venturi 2 et avec la grille de combustion 6.This burner 1 comprises a venturi tube 2 which extends between an inlet end 3 communicating with the atmosphere and an outlet end 4 communicating with a premix chamber 5, upstream of a combustion grate 6 or any other combustion head. The bedroom premix 5 is delimited by a solid side wall, in general metallic and it communicates only with the venturi tube 2 and with combustion grate 6.

Le tube venturi 2 comporte classiquement, d'amont en aval, un court tronçon convergent, un col, puis un long tronçon divergent, et il est pourvu à son extrémité d'entrée 3 d'un injecteur de gaz combustible 7.The venturi tube 2 conventionally comprises, from upstream to downstream, a short converging section, a pass, then a long divergent section, and it is provided at its inlet end 3 of a fuel gas injector 7.

Lors du fonctionnement du brûleur, de l'air est aspiré à l'extrémité d'entrée 3 sous l'effet de l'injection du gaz combustible. Cet air se mélange avec le gaz combustible dans le tube venturi 2 et dans la chambre de prémélange 5, puis le prémélange ainsi réalisé est brûlé en sortant de la chambre de prémélange 5 par la grille de combustion 6.During operation of the burner, air is sucked in at the inlet end 3 under the effect of the injection combustible gas. This air mixes with the combustible gas in the venturi tube 2 and in the premix chamber 5, then the premix thus produced is burned out of the premix chamber 5 by the combustion grate 6.

Dans tous les exemples représentés, le brûleur 1 comporte un unique tube venturi 2, mais il pourrait comporter éventuellement plusieurs tubes venturis débouchant dans la même chambre de prémélange, sans sortir du cadre de la présente invention.In all the examples shown, the burner 1 has a single venturi tube 2, but it could have possibly several venturis tubes opening into the same premix chamber, without departing from the scope of the present invention.

Par ailleurs, dans les exemples représentés, le tube venturi 2 débouche dans la chambre de prémélange 5 à travers le fond 5a de cette chambre, à une extrémité longitudinale 5b de ladite chambre, et le tube venturi 2 est replié sous le fond 5a sensiblement parallèlement à la grille de combustion 6, en direction de la deuxième extrémité longitudinale 5b de la chambre de prémélange.Furthermore, in the examples shown, the tube venturi 2 opens into the premix chamber 5 through the bottom 5a of this chamber, at a longitudinal end 5b of said chamber, and the venturi tube 2 is folded under the bottom 5a substantially parallel to the grid of combustion 6, towards the second longitudinal end 5b of the premix chamber.

Sauf dans le cas particulier considéré à la figure 4, le tube venturi 2 pourrait toutefois être disposé différemment par rapport à la chambre de prémélange 5, et en particulier, il pourrait être disposé sous le fond 5a de la chambre de prémélange sensiblement perpendiculairement à la grille de combustion 6.Except in the particular case considered in the figure 4, the venturi tube 2 could however be arranged differently from the premix chamber 5, and in particular, it could be arranged under the bottom 5a of the premix chamber substantially perpendicular to the combustion grate 6.

Dans tous les exemples considérés ici, on crée dans le tube venturi ou dans la chambre de prémélange 5 des contre-bruits en opposition de phase avec les vibrations acoustiques générées par l'injection du gaz combustible et l'entrée concomitante d'air à l'extrémité d'entrée 3 du tube venturi, et générées également par la circulation rapide du mélange gazeux dans le tube venturi. On atténue ainsi ces vibrations acoustiques, ce qui permet d'obtenir un fonctionnement plus silencieux du brûleur 1. In all the examples considered here, we create in the venturi tube or in the premix chamber 5 of counter-noises in phase opposition with vibrations acoustics generated by the injection of combustible gas and the concomitant air inlet at the inlet end 3 of the tube venturi, and also generated by the rapid circulation of gas mixture in the venturi tube. We thus mitigate these acoustic vibrations, which allows an operation quieter burner 1.

Dans l'exemple de la figure 1, les contre-bruits sont générés au moyen de deux cavités résonantes en forme de tubes 10, dit tubes "quart d'onde". Ces tubes présentent une section de forme quelconque et s'étendent chacun longitudinalement entre d'une part une extrémité ouverte 11 communiquant avec l'intérieur du tube venturi 2, et d'autre part un fond fermé 12.In the example in Figure 1, the noise barriers are generated by means of two resonant cavities in the form of tubes 10, called "quarter-wave" tubes. These tubes have a section of any shape and each extend longitudinally between on the one hand an open end 11 communicating with the inside of the venturi tube 2, and on the other hand a closed bottom 12.

Les vibrations acoustiques qui ont lieu à l'intérieur du tube venturi 2 pénètrent dans chacun des deux tubes 10 par leur extrémité ouverte 11, et ces vibrations parcourent la longueur longitudinale, respectivement l1, l2 de ces tubes avant de se réfléchir sur leur fond 12, puis elles parcourent à nouveau la longueur longitudinale desdits tubes en sens inverse avant de revenir dans le tube venturi 2.The acoustic vibrations which take place inside the venturi tube 2 penetrate into each of the two tubes 10 through their open end 11, and these vibrations travel the longitudinal length, respectively l 1, l 2 of these tubes before being reflected on their bottom 12, then they again travel the longitudinal length of said tubes in the opposite direction before returning to the venturi tube 2.

De cette façon, lorsque l'intérieur du tube venturi 2 est le siège de vibrations acoustiques dont la fréquence correspond à une longueur d'onde égale à quatre fois la longueur longitudinale l1 ou l2 d'un des deux tubes 10, ce tube 10 renvoie dans le tube venturi des vibrations acoustiques en opposition de phase avec les vibrations générées dans le tube 2.In this way, when the interior of the venturi tube 2 is the seat of acoustic vibrations whose frequency corresponds to a wavelength equal to four times the longitudinal length l 1 or l 2 of one of the two tubes 10, this tube 10 returns in the venturi tube acoustic vibrations in phase opposition with the vibrations generated in the tube 2.

Autrement dit, les deux tubes 10 génèrent des contre-bruits en opposition de phase avec les bruits générés dans le tube venturi 2 au voisinage de deux fréquences prédéterminées correspondant à des longueurs d'ondes λ1 et λ2 telles que les longueurs l1 et l2 des tubes soient respectivement sensiblement égales au quart des longueurs d'ondes λ1 et λ2, ou plus généralement égales à des multiples entiers impairs du quart des longueurs d'ondes λ1 et λ2.In other words, the two tubes 10 generate counter-noises in phase opposition with the noises generated in the venturi tube 2 in the vicinity of two predetermined frequencies corresponding to wavelengths λ1 and λ2 such that the lengths l 1 and l 2 tubes are respectively substantially equal to a quarter of the wavelengths λ1 and λ2, or more generally equal to odd integer multiples of a quarter of the wavelengths λ1 and λ2.

Avantageusement, les extrémités d'entrée 11 des tubes 10 sont disposées de façon à communiquer avec une zone du volume intérieur du brûleur où les vibrations acoustiques ayant la fréquence à absorber présentent une amplitude maximum. Advantageously, the inlet ends 11 of the tubes 10 are arranged to communicate with an area of the internal volume of the burner where the acoustic vibrations having the frequency to be absorbed have an amplitude maximum.

En particulier, les extrémités d'entrée 11 des tubes 10 sont de préférence disposées à des distances respectives l3, l4 de l'extrémité d'entrée 3 du tube venturi qui sont respectivement sensiblement égales à des multiples entiers impairs du quart des longueurs d'ondes λ1 et λ2 des bruits qui sont respectivement étouffés par les deux tubes 10.In particular, the inlet ends 11 of the tubes 10 are preferably arranged at respective distances l 3, l 4 from the inlet end 3 of the venturi tube which are respectively substantially equal to odd integer multiples of a quarter of the lengths of waves λ1 and λ2 of the noises which are respectively muffled by the two tubes 10.

De façon plus générale, la distance l3 peut être comprise entre 0,2 k1 λ1 et 0,3 k1 λ1, et la distance l4 peut être comprise entre 0,2 k2 λ2 et 0,3 k2 λ2, où k1 et k2 sont des nombres entiers impairs, de préférence égaux à 1 ou 3.More generally, the distance l 3 can be between 0.2 k1 λ1 and 0.3 k1 λ1, and the distance l 4 can be between 0.2 k2 λ2 and 0.3 k2 λ2, where k1 and k2 are odd whole numbers, preferably equal to 1 or 3.

Comme dans toutes les formes de réalisation de la présente invention, les distances entre l'extrémité d'entrée 3 du tube venturi et les entrées 11 des tubes (plus généralement les ouvertures d'entrée des espaces creux antibruit) sont des distances curvilignes correspondant au trajet moyen suivi par les gaz depuis l'extrémité d'entrée 3 du tube venturi jusqu'aux ouvertures d'entrée en question.As in all embodiments of the present invention the distances between the input end 3 of the venturi tube and the inlets 11 of the tubes (more generally the entrance openings of the noise-canceling hollow spaces) are curvilinear distances corresponding to the average path followed by the gases from the inlet end 3 of the tube venturi to the entry openings in question.

Dans un exemple particulier de réalisation, pour atténuer deux pics de vibrations acoustiques à environ 1000 et 2300 Hz, on a utilisé des tubes 10 de section circulaire présentant un diamètre intérieur de 3 millimètres, avec les paramètres suivants : l1 = 3,2 cm, l2 = 8,6 cm, l3 = 3,6 cm, l4 = 8,5 cm.In a particular embodiment, to attenuate two peaks of acoustic vibrations at around 1000 and 2300 Hz, tubes 10 of circular section with an inside diameter of 3 millimeters were used, with the following parameters: l 1 = 3.2 cm , l 2 = 8.6 cm, l 3 = 3.6 cm, l 4 = 8.5 cm.

On a représenté sur la figure 2 un spectre de vibrations acoustiques mesurées dans un exemple de réalisation particulier du brûleur 1 représenté sur la figure 1, d'une part sans les deux tubes 10 (en trait plein), et d'autre part avec les deux tubes 10 (en pointillés).FIG. 2 shows a spectrum of acoustic vibrations measured in an exemplary embodiment particular of the burner 1 represented in FIG. 1, on the one hand without the two tubes 10 (in solid lines), and on the other hand with the two tubes 10 (dotted lines).

On peut voir que sans les deux tubes 10, le spectre présente deux pics P1 et P2 de vibrations acoustiques aux environs de 1000 et 2300 Hz, et que ces pics sont supprimés grâce à l'adjonction des deux tubes 10.We can see that without the two tubes 10, the spectrum presents two peaks P1 and P2 of acoustic vibrations at around 1000 and 2300 Hz, and that these peaks are suppressed thanks to the addition of the two tubes 10.

Il va de soi que le brûleur 1 pourrait être doté d'un seul tube 10 ou éventuellement de plus de deux tubes 10, en fonction des fréquences de bruit que l'on souhaite absorber.It goes without saying that burner 1 could be provided of a single tube 10 or possibly of more than two tubes 10, depending on the desired noise frequencies absorb.

De plus, les tubes 10 pourraient éventuellement communiquer avec la chambre de prémélange 5 plutôt qu'avec le tube venturi 2, ils pourraient le cas échéant présenter une forme rectiligne plutôt que curviligne telle que celle montrée sur la figure 1 et ils pourraient éventuellement ne pas être disposés dans le plan de symétrie du brûleur 1.In addition, the tubes 10 could possibly communicate with the premix chamber 5 rather than with the venturi tube 2, they could if necessary present a straight rather than curvilinear shape such as that shown in Figure 1 and they might possibly not not be arranged in the plane of symmetry of burner 1.

Il est toutefois avantageux que les tubes 10 soient disposés avec leurs axes longitudinaux dans le plan de symétrie du brûleur 1, comme représenté sur la figure 1, dans la mesure où cette disposition permet de réaliser simplement le brûleur 1 par emboutissage puis assemblage de deux demi-coques métalliques, une de ces demi-coques étant représentée schématiquement sur la figure 1. Chaque demi-coque représente alors la moitié du tube venturi 2, de la paroi latérale de la chambre de prémélange 5, et de chaque tube 10.It is however advantageous that the tubes 10 are arranged with their longitudinal axes in the plane of symmetry of the burner 1, as shown in FIG. 1, insofar as this provision makes it possible to carry out simply burner 1 by stamping then assembly of two metal half-shells, one of these half-shells being shown schematically in Figure 1. Each half-shell then represents half of the venturi tube 2, of the side wall of the premix chamber 5, and of each tube 10.

Dans le cas d'une telle réalisation, la grille de combustion 6 sera généralement rapportée au-dessus de la chambre de prémélange 5 après assemblage des deux demi-coques. Toutefois, il est également possible d'utiliser à la place de la grille 6 une tête de combustion formée par des canaux de sortie du mélange air-gaz combustible, ces canaux étant réalisés simplement par la juxtaposition des deux demi-coques.In the case of such an embodiment, the grid of combustion 6 will usually be reported above the premix chamber 5 after assembly of the two half-shells. However, it is also possible to use place of the grid 6 a combustion head formed by air-fuel gas mixture outlet channels, these channels being achieved simply by the juxtaposition of the two half-shells.

Comme représenté sur la figure 3, les tubes 10 pourraient être remplacés par une ou plusieurs cavités résonantes 20 ayant une autre forme. La cavité résonante 20 se présente sous forme d'une capacité de volume V, dite "résonateur d'Helmholtz" conçue pour produire à l'intérieur du brûleur 1 des contre-bruits en opposition de phase avec les bruits présentant la fréquence à atténuer.As shown in Figure 3, the tubes 10 could be replaced by one or more cavities resonant 20 having another form. The resonant cavity 20 is in the form of a volume capacity V, called "Helmholtz resonator" designed to produce inside of the burner 1 against noise in phase opposition with noises presenting the frequency to be attenuated.

La cavité résonante 20 communique avec l'intérieur du tube venturi 2 ou la chambre de prémélange 5 par l'intermédiaire d'une entrée 21 et elle est délimitée par une paroi étanche 22. The resonant cavity 20 communicates with the interior of the venturi tube 2 or the premix chamber 5 via an entrance 21 and it is delimited by a wall waterproof 22.

Pour une cavité 20 présentant un seul orifice d'entrée 21, la fréquence à atténuer s'exprime par la formule classique suivante :

Figure 00090001
où :

  • f est la fréquence à atténuer, en Hertz,
  • S est la section de l'orifice d'entrée 21,
  • c est la vitesse de propagation des ondes acoustiques,
  • V est le volume intérieur de la cavité 20,
  • et h est la longueur de l'ouverture d'entrée 21, c'est-à-dire la distance entre le volume intérieur du brûleur et la capacité V au niveau de ladite ouverture d'entrée 21 : si la capacité V est accolée à la paroi du tube venturi 2 ou de la chambre de prémélange 5, h est simplement l'épaisseur de cette paroi.
For a cavity 20 having a single inlet orifice 21, the frequency to be attenuated is expressed by the following conventional formula:
Figure 00090001
or :
  • f is the frequency to be attenuated, in Hertz,
  • S is the section of the inlet orifice 21,
  • c is the speed of propagation of the acoustic waves,
  • V is the interior volume of the cavity 20,
  • and h is the length of the inlet opening 21, that is to say the distance between the internal volume of the burner and the capacity V at the level of said inlet opening 21: if the capacity V is attached to the wall of the venturi tube 2 or of the premix chamber 5, h is simply the thickness of this wall.

Comme les tubes 10 déjà décrits, la cavité résonante 20 peut communiquer avec le tube venturi 2 ou avec la chambre de prémélange 5, et il peut être prévu une ou plusieurs cavités résonantes en fonction du nombre de fréquences à atténuer.Like the tubes 10 already described, the resonant cavity 20 can communicate with the venturi tube 2 or with the premix chamber 5, and one or more can be provided several resonant cavities depending on the number of frequencies to be attenuated.

Comme déjà indiqué pour l'exemple de la figure 1, l'entrée 21 de la cavité 20 est de préférence disposée dans une zone où l'amplitude des vibrations acoustiques est maximale dans le brûleur, par exemple à une distance l5 de l'extrémité d'amont 3 du tube venturi qui est comprise entre 0,2 et 0,3 fois un multiple entier impair k de la longueur d'onde λ du bruit à atténuer, k étant de préférence égal à 1 ou 3. La distance l5 est de préférence voisine de λ/4 ou plus généralement voisine d'un multiple entier impair k de λ/4, k étant de préférence égal à 1 ou 3.As already indicated for the example of FIG. 1, the inlet 21 of the cavity 20 is preferably arranged in an area where the amplitude of the acoustic vibrations is maximum in the burner, for example at a distance l 5 from the upstream end 3 of the venturi tube which is between 0.2 and 0.3 times an odd integer multiple k of the wavelength λ of the noise to be attenuated, k preferably being equal to 1 or 3. The distance l 5 is preferably close to λ / 4 or more generally close to an odd integer multiple k of λ / 4, k being preferably equal to 1 or 3.

Par ailleurs, la cavité résonante 20 est de préférence, mais non exclusivement, disposée de façon symétrique par rapport au plan de symétrie du brûleur 1, de façon que l'ensemble du brûleur 1, sauf le cas échéant la grille de combustion 6, puisse être réalisé par emboutissage de deux demi-coques métalliques assemblées selon le plan de symétrie, comme explicité ci-dessus en regard de la figure 1.Furthermore, the resonant cavity 20 is preferably, but not exclusively, symmetrically arranged with respect to the plane of symmetry of the burner 1, so that the entire burner 1, except where applicable the grate combustion 6, can be achieved by stamping two metal half-shells assembled according to the plane of symmetry, as explained above with reference to FIG. 1.

Dans les exemples représentés sur les figures 4 et 5, les contre-bruits sont générés au moyen d'un tube de liaison 30, de section quelconque, qui s'étend entre d'une part une extrémité d'amont 31 ou ouverture d'entrée communiquant avec le tube venturi 2, et d'autre part une extrémité d'aval 32 communiquant avec le tube venturi ou la chambre de prémélange 5.In the examples shown in Figures 4 and 5, the counter-noises are generated by means of a tube of link 30, of any section, which extends between a share an upstream end 31 or communicating entrance opening with the venturi tube 2, and on the other hand an end downstream 32 communicating with the venturi tube or the premix 5.

Les extrémités du tube 30 peuvent éventuellement communiquer toutes les deux avec la chambre de prémélange 5.The ends of the tube 30 can optionally both communicate with the premix chamber 5.

Dans les deux cas représentés sur les figures 4 et 5, le mélange gazeux qui traverse le brûleur 1 sans passer par le tube de liaison 30 parcourt une distance L dans le tube venturi et la chambre de prémélange 5 entre les extrémités 31 et 32 du tube de liaison, et le tube de liaison présente une longueur, respectivement l6, l7, qui est soit inférieure, soit supérieure à la distance L et qui diffère de la distance L par une longueur n λ/2, où n est un nombre entier impair et où λ est la longueur d'onde des bruits à étouffer.In the two cases shown in FIGS. 4 and 5, the gas mixture which passes through the burner 1 without passing through the connection tube 30 travels a distance L in the venturi tube and the premix chamber 5 between the ends 31 and 32 of the tube of connection, and the connection tube has a length, respectively l 6, l 7, which is either less than or greater than the distance L and which differs from the distance L by a length n λ / 2, where n is a number odd integer and where λ is the wavelength of the noises to be suppressed.

Dans la pratique, n sera le plus souvent égal à 1.In practice, n will most often be equal to 1.

Dans l'exemple de la figure 4, la longueur l6 du tube de liaison 30 est inférieure d'une demi-longueur d'onde à la longueur L, et dans l'exemple de la figure 5, la longueur l7 du tube de liaison 30 est supérieure d'une demi-longueur d'onde à la longueur L.In the example of FIG. 4, the length l 6 of the connecting tube 30 is half a wavelength shorter than the length L, and in the example of FIG. 5, the length l 7 of the tube link 30 is half a wavelength longer than length L.

Du fait de sa longueur, le tube de liaison 30 génère dans tous les cas à son extrémité 32 un contre-bruit en opposition de phase avec les vibrations acoustiques du mélange gazeux pour la fréquence prédéterminée à amortir. Due to its length, the connecting tube 30 generates in any case at its end 32 a noise counter phase opposition with the acoustic vibrations of the gas mixture for the predetermined frequency to be damped.

Comme dans les exemples précédents, le tube 30 est de préférence, mais non exclusivement, disposé dans le plan de symétrie du brûleur 1, de façon que ce brûleur, sauf le cas échéant sa grille de combustion 6, puisse être réalisé par emboutissage de deux demi-coques métalliques puis assemblage de ces deux demi-coques le long du plan de symétrie.As in the previous examples, the tube 30 is preferably, but not exclusively, arranged in the plane of symmetry of burner 1, so that this burner, except the if necessary its combustion grate 6, can be produced by stamping two metal half-shells then assembly of these two half-shells along the plane of symmetry.

Dans les exemples représentés sur les figures 4 et 5, la distance l8 entre l'extrémité 31 du tube de liaison et l'extrémité d'amont 3 du tube venturi peut être comprise entre 0,2 k λ et 0,3 k λ, cette distance étant avantageusement voisine de k λ/4, et la distance l9 entre la deuxième extrémité 32 du tube de liaison et l'extrémité d'amont 3 du tube venturi peut être comprise entre 0,2 q λ et 0,3 q λ et avantageusement voisine de q λ/4, où k et q sont deux nombres entiers impairs différents et où λ est la longueur d'onde du bruit à atténuer (k est de préférence égal à 1 ou 3).In the examples shown in Figures 4 and 5, the distance l 8 between the end 31 of the connection tube and the upstream end 3 of the venturi tube can be between 0.2 k λ and 0.3 k λ , this distance being advantageously close to k λ / 4, and the distance l 9 between the second end 32 of the connecting tube and the upstream end 3 of the venturi tube can be between 0.2 q λ and 0.3 q λ and advantageously close to q λ / 4, where k and q are two different odd integers and where λ is the wavelength of the noise to be attenuated (k is preferably equal to 1 or 3).

Enfin, dans l'exemple représenté sur la figure 6, les contre-bruits sont générés au moyen d'une cavité résonante annulaire 35 ménagée à l'extrémité d'amont 3 du tube venturi.Finally, in the example shown in Figure 6, the counter-noises are generated by means of a resonant cavity annular 35 formed at the upstream end 3 of the tube venturi.

Cette cavité résonante annulaire est délimitée radialement vers l'extérieur par une paroi annulaire extérieure 33 pleine qui délimite latéralement le tube venturi 2, et radialement vers l'intérieur par une paroi annulaire 34 pleine présentant successivement un tronçon convergent, un col, puis un tronçon divergent,This annular resonant cavity is delimited radially outwards by an annular wall outer 33 full which laterally delimits the tube venturi 2, and radially inward by a wall full annular 34 having successively a section converge, a pass, then a divergent section,

La paroi 34 est en contact périphérique étanche avec de la paroi extérieure 33 en amont (les extrémités d'amont de ces deux parois ne sont pas forcément confondues), et elle s'étend vers l'aval à l'intérieur de la paroi extérieure 33 jusqu'à une extrémité ouverte 34a qui communique avec l'intérieur de la paroi 33.The wall 34 is in sealed peripheral contact with of the outer wall 33 upstream (the upstream ends of these two walls are not necessarily confused), and it extends downstream inside the outer wall 33 to an open end 34a which communicates with the inside of the wall 33.

Ainsi, la cavité résonante annulaire 35 s'étend selon l'axe longitudinal du tube venturi 2 entre une extrémité d'amont 35a fermée et une extrémité d'aval 35b qui forme une ouverture annulaire constituant l'entrée de la cavité résonante.Thus, the annular resonant cavity 35 extends along the longitudinal axis of the venturi tube 2 between a upstream end 35a closed and a downstream end 35b which forms an annular opening constituting the entrance to the resonant cavity.

Ces extrémités d'amont et d'aval sont séparées l'une de l'autre par une distance axiale l10 sensiblement égale au quart de la longueur d'onde du bruit à étouffer, ou plus généralement sensiblement égale à un multiple impair du quart de cette longueur d'onde (de préférence λ/4 ou 3λ/4), la distance entre l'extrémité d'entrée 3 du tube venturi et l'ouverture d'entrée 35b de la cavité résonante étant comprise entre 0,2 k λ et 0,3 k λ où k est un nombre entier impair (de préférence 1 ou 3) et λ est la longueur d'onde du bruit à atténuer.These upstream and downstream ends are separated from each other by an axial distance l 10 substantially equal to a quarter of the wavelength of the noise to be suppressed, or more generally substantially equal to an odd multiple of a quarter. of this wavelength (preferably λ / 4 or 3λ / 4), the distance between the inlet end 3 of the venturi tube and the inlet opening 35b of the resonant cavity being between 0.2 k λ and 0.3 k λ where k is an odd integer (preferably 1 or 3) and λ is the wavelength of the noise to be attenuated.

De préférence, dans toutes les formes de réalisation de l'invention, le volume intérieur du brûleur présente, au droit de l'ouverture d'entrée de l'espace creux antibruit (cavité résonante ou tube de liaison), une section de passage du mélange air-gaz qui est au moins 10 fois plus grande que la section de ladite ouverture d'entrée, la section de passage du mélange air-gaz étant la section du volume intérieur du brûleur prise perpendiculairement à la direction moyenne d'écoulement des gaz.Preferably, in all embodiments of the invention, the internal volume of the burner has, at right of the entrance opening of the noise-canceling hollow space (resonant cavity or connecting tube), a section of passage of the air-gas mixture which is at least 10 times more large than the section of said inlet opening, the cross section of the air-gas mixture being the section of the internal volume of the burner taken perpendicular to the average direction of gas flow.

Claims (11)

  1. A gas burner, comprising an internal volume (2,5) which receives air as well as a combustible gas and which discharges to the atmosphere through a combustion head (6), this burner generating noises in its internal volume during its operation and comprising in addition a hollow noise-reducing space (10, 20, 30, 35) for generating counter noises in its internal volume (2,5), in phase opposition to the aforementioned noises. at least for absorbing a certain frequency corresponding to a pre-specified wavelength, this hollow noise-reducing space being delimited by a solid wall and communicating with the internal volume (2, 5) of the burner at least through one inlet opening (11, 21, 31, 35b), the counter noises being obtained only by the geometry of said hollow noise-reducing space, the internal volume including a venturi tube (2) having an upstream end (3) which is provided with a combustible gas injector (7) and which is shaped to induce air under the effect of the combustible gas injection thus generating the aforementioned noises, the inlet opening (11, 21, 31, 35b) of the hollow noise-reducing space communicating with the venturi tube, characterised in that the inlet opening (11, 21, 31, 35b) is arranged at a distance from the upstream end (3) of the venturi tube which is between 0.2 k λ and 0.3 k λ, where k is an odd integer and where λ is the pre-specified wavelength.
  2. A burner according to claim 1, having a plane of symmetry and comprising two fitted half-shells which are assembled together and which each delimit one half of the internal volume (2, 5) of the burner and the hollow noise-reducing space.
  3. A burner according to any one of the claims 1 and 2, wherein the hollow noise-reducing space is a closed resonant cavity (10, 20, 35) which communicates with the internal volume (2, 5) of said burner only through the inlet opening (11,21,35b).
  4. A burner according to claim 3, wherein the resonant cavity is a resonant tube (10) which extends over a certain length (l1, l2) between the inlet opening (11) and a closed end (12), the length of this resonant tube being approximately equal to an odd whole multiple of a quarter of the pre-specified wavelength.
  5. A burner according to claim 3 wherein the venturi tube (2) has towards its upstream end (3) an external solid annular wall (33) which surrounds an internal so!id annular wall (34) delimiting with the external wall an annular volume (35) which forms the resonant cavity, this resonant cavity extending along the longitudinal axis of the venturi tube (2) between on the one hand a closed upstream end (35a) near the upstream end (3) of the venturi tube and on the other hand a downstream end (35b) which forms an annular opening constituting the inlet opening of the resonant cavity, and these upstream and downstream ends being separated from each other by an axial distance (110) approximately equal to an odd multiple of a quarter of the pre-specified wavelength.
  6. A burner according to any one of claims 1 and 2, wherein the hollow noise-reducing space is a connection tube (30) which extends over a certain length (16, 17) between first and second ends (31, 32) both communicating with the internal volume (2, 5) of said burner, the first end (31) of the connection tube forming the aforementioned inlet opening, the second end (32) being located downstream from the first end (31), the air and the combustible gas which passes through the burner without passing through the connection tube (30) travelling a specified length (L) between the two ends of the connection tube, and the length of the connection tube differing from said specified length (L) by a length n λ/2, where n is an odd integer.
  7. A burner according to claim 6, wherein the length (l6, l7) of the connection tube (30) is greater than the specified length (L) travelled between the two ends (31, 32) of said connection tube by the air and the combustible gas which pass through the burner without passing through the connection tube.
  8. A burner according to claim 6, wherein the venturi tube discharges into a pre-mixing chamber (5) upstream of the combustion head (6), the pre-mixing chamber (5) extending longitudinally between two ends (5b, 5c) and communicating with the venturi tube (2) at only one (5b) of its ends, the venturi tube being arranged along the pre-mixing chamber, and the length (16) of the connection tube (30) being less than the pre-specified length (L) travelled between the two ends (31, 32) of said connection tube by the air and the combustible gas which passes through the burner without passing through the connection tube.
  9. A burner according to any one of the claims 6 to 8, wherein the second end (32) of the connection tube communicates with the venturi tube (2), is arranged at a distance (19) from the upstream end (3) of the venturi tube which is between 0.2 q λ and 0.3 q λ, where q is an odd integer greater than k.
  10. A burner according to any one of the previous claims, wherein k is 1 or 3.
  11. A burner according to any one of the previous claims, wherein the internal volume of the burner has, at right angles to the inlet opening (11, 21, 31, 35b) of the hollow noise-reducing space, a passage section for the air-gas mixture which is at least 10 times greater than the section of said inlet opening.
EP96400420A 1995-03-02 1996-02-28 Gas burner with improved acoustical attenuation Expired - Lifetime EP0730122B1 (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
FR9502433 1995-03-02
FR9502433A FR2731265B1 (en) 1995-03-02 1995-03-02 GAS BURNER HAVING IMPROVED ACOUSTIC DISCRETION

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EP0730122A1 EP0730122A1 (en) 1996-09-04
EP0730122B1 true EP0730122B1 (en) 1999-07-28

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DE (1) DE69603389T2 (en)
ES (1) ES2133905T3 (en)
FR (1) FR2731265B1 (en)

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AT409537B (en) * 1999-09-24 2002-09-25 Vaillant Gmbh CLOSED COMBUSTION SYSTEM
ITMI20081143A1 (en) * 2008-06-25 2009-12-26 Baxi Spa COMPACT SILENCER FOR CONDENSING BOILER
US10711997B2 (en) 2017-10-03 2020-07-14 Lennox Industries Inc. Burner box liner for low NOx emission furnace
US10711998B2 (en) 2017-10-03 2020-07-14 Lennox Industries Inc. Fresh air intake for low NOx emission furnace
US11187433B2 (en) 2017-10-03 2021-11-30 Lennox Industries Inc. Pre-mix burner assembly for low NOx emission furnace
US11162677B2 (en) * 2019-01-18 2021-11-02 Lennox Industries Inc. Air intake coupling with noise suppression for low NOx emission furnace
CN210004391U (en) * 2019-05-27 2020-01-31 浙江广涛卫厨有限公司 Fire grate of burner
CN210004392U (en) * 2019-05-27 2020-01-31 浙江广涛卫厨有限公司 Fire grate segment of novel burner

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CH115352A (en) * 1925-08-28 1926-10-01 Alfred Fleisch Method and device for sound absorption.
DE2117337C3 (en) * 1971-04-08 1978-04-20 Robert Bosch Gmbh, 7000 Stuttgart Burners for gas-fired devices
DE2263471C3 (en) * 1972-12-27 1975-11-27 Joh. Vaillant Kg, 5630 Remscheid Silencer designed as a Helmholtz resonator for a device gas burner
JPS63172817A (en) * 1987-01-13 1988-07-16 Rinnai Corp Forced blasting type combustion apparatus
WO1993010401A1 (en) * 1991-11-15 1993-05-27 Siemens Aktiengesellschaft Arrangement for suppressing combustion-caused vibrations in the combustion chamber of a gas turbine system

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Publication number Publication date
DE69603389D1 (en) 1999-09-02
FR2731265B1 (en) 1997-05-09
FR2731265A1 (en) 1996-09-06
DE69603389T2 (en) 2000-04-13
ES2133905T3 (en) 1999-09-16
EP0730122A1 (en) 1996-09-04

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