EP0956476B1 - Ancrage d'une falmme laminaire de combustible gazeux - Google Patents

Ancrage d'une falmme laminaire de combustible gazeux Download PDF

Info

Publication number
EP0956476B1
EP0956476B1 EP97954925A EP97954925A EP0956476B1 EP 0956476 B1 EP0956476 B1 EP 0956476B1 EP 97954925 A EP97954925 A EP 97954925A EP 97954925 A EP97954925 A EP 97954925A EP 0956476 B1 EP0956476 B1 EP 0956476B1
Authority
EP
European Patent Office
Prior art keywords
flame
obstacle
jet
mixture
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
EP97954925A
Other languages
German (de)
English (en)
Other versions
EP0956476A1 (fr
Inventor
Enrico Sebastiani
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Individual
Original Assignee
Individual
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Individual filed Critical Individual
Publication of EP0956476A1 publication Critical patent/EP0956476A1/fr
Application granted granted Critical
Publication of EP0956476B1 publication Critical patent/EP0956476B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • 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
    • F23D14/48—Nozzles
    • F23D14/58—Nozzles characterised by the shape or arrangement of the outlet or outlets from the nozzle, e.g. of annular configuration
    • 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
    • F23D14/70—Baffles or like flow-disturbing devices
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23D—BURNERS
    • F23D2209/00—Safety arrangements
    • F23D2209/20—Flame lift-off / stability

Definitions

  • the present invention relates to gaseous fuel combustion systems with either natural or forced draft, in particular to a method and apparatuses in accomplishment of same, for controlling the outflow of the air-gas mixture through the flame openings of burners, totally or partially premixed, in order to obtain: a stable flame, detached from the flame openings area, low emissions, in the most wide field of burner capacity modulation required in practice, even in feeding conditions with test gases foreseen from Standards for extreme conditions of use, in a so simple and practical way to be used also for apparatus with capacity of only few kW.
  • the gas combustion system is the assembly of the burner, with the combustion chamber, the heat exchanger, the means for the circulation of air and exhausts, if existing, as well as the control apparatus with its sensors; more elements of the assembly can form a sole body therefore a distinction is only possible considering the function of each element.
  • the gas combustion systems are the main functional assembly of domestic and industrial appliances as central heating boilers, water heaters, of two main types: instantaneous and storage water heater, room heater and furnaces, gas cookers etc.
  • the invention applies in particular to fuel-gas combustion systems, where:
  • the front of flame is recognisable because it emits in the visible, even if the specific maximum emission, due to OH and CH ions, is respectively in the wavelength between 305 and 320 mm and around 431.5 and 438 mm.
  • the apparatuses of the kind disclosed in the preamble of the claims arise when the burner capacity is modulating down therefore the mixture exit velocity reduce or when instead of the standard fuel-gas for which the apparatus is set, a fuel-gas from the same family as said standard fuel-gas but prone on flame blow-off or prone to flash back are fed.
  • the burner flame openings surface may attain critical temperature value, and in some other occasion, the flame may become unstable, resulting in poor combustion of fuel-gas.
  • the flame openings surface which reach temperature up to 500°C, must be of costly materials and moreover the thermal stress reduces the possibility of flame openings design.
  • the WO-A-8 901 116 claims the following method: in an atmospheric burner, A) inside the burner it is sucked a quantity of primary air which is at least 80% of the air stoichiometrically necessary to the combustion; B) the secondary air, from the very first combustion steps, laps all sides of every single bladed small flame exiting from each group of slots foreseen on the burner diffuser, in such a way that the total air involved exceeds the stoichiometrical air value; C) the combustion starts and is completed within the bladed thickness of the flame,
  • the burners considered are only atmospheric, the only foreseen burner diffuser is in sheet metal with thickness of around 0.5 mm., the group of slots is defined "each group of slots being appropriately subdivided longitudinally into two subgroups of slots lying not so close together" to anchor the flame on the unpunched surface between subgroups of slots.
  • the anchorage zone reaches high temperatures particularly in limit conditions, moreover the thermal stress, caused from temperature differences of 200-300°C in few millimetres, forces the use of costly materials and constrains special shape and arrangement of the slots which limits the specific capacity of said burner. Furthermore because the exit velocity is limited by the inefficacy of the flame anchorage, the specific capacity of the burner itself is again limited.
  • the difficulty of the anchorage of this type of flame imposes also the introduction of more or less expensive regulation systems as per EP0606527A1 deposited on 16 August 1993.
  • WO-A-9736135 (prior art under Article 54(3) EPC) describes and claims a method and apparatuses for the fulfilment of the same to maintain the flame, around an optimum position, regulating at least one of the three variable quantities of the mixture exiting the flame port/s: the value of the premixture rate ⁇ , the outflow velocity, the temperature upstream the flame front.
  • WO-A-9736135 uses modification of the fan speed, of the flame openings cross section and heat elements. Fluids dynamic obstacles are foreseen to create downstream a stagnation zone, anchorage of the flame, but not formed and positioned in a way to create downstream divergent fluids threads. The dilution of the mixture downstream the flame openings to locally reduce the flame speed is not foreseen
  • the aim of this invention is to provide a method and apparatuses in fulfilment of same, to eliminate the aforesaid difficulties, to make possible the proper combustion in very compact combustion systems, even formed by a sole body, to reduce the emission to a very minimum, to maintain the temperature of the flame opening/s surface low to allow the use of steel, aluminium, and other inexpensive materials, all previously described goals must be achieved in all operating conditions caused by the capacity modulation or/and the use of limit gases. The feasibility must be so simple, to be used also for combustion systems of capacity of only few hundred watt.
  • This aim is reached by applying the method so that, in a gaseous fuel combustion system with either natural or forced draft, a premixed, atmospheric or forced burner form the fuel-gas air mixture, from almost stoichiometric to strongly hyperstoichiometric, which flows in combustion chamber from at least one flame opening with velocity, distribution such as to obtain a substantially laminar flow and velocity over 0.4 m/sec.
  • An almost homogeneous single jet of mixture exits from each flame opening, whereby, immediately down-stream of said opening, the gaseous content of the volume surrounding the jet is sucked into said jet and mixed therewith.
  • the jet velocity is, in all operating conditions, higher than the combustion velocity of the mixture in said condition, at least for a distance equal to that of at least one fluids dynamic obstacle which is immersed in said jet, down stream the flame opening/s.
  • Said obstacle is always completely detached from said flame opening/s, having such shape and dimensions to create down stream a stagnation zone, anchorage of the flame in all operating conditions, the distance of the down-stream side being at least big as the width of the at least one flame opening.
  • the flow field, down stream and on the side of the obstacle, is almost laminar with progressively divergent fluids threads, to obtain a flame at the beginning ignited from a specific device, from laminar to wrinkled, characterised by a large surface and very low thickness anchored to the obstacle at least in some points by vortexes related to the stagnation zone, said flame doesn't touch at all the flame openings surface.
  • the jets flowing out from different openings join together after few to some ten mm. remaining the jet velocity over the combustion velocity at the given conditions of mixture and temperature; in this case mainly recycled mixture, is sucked into said jet/s just down stream the flame openings and the fluids dynamic obstacles, no longer related with the shape and arrangement of flame openings, may form a mesh net or, for instance, an assembly of parallel rods having centreline up to perpendicular to the axes of elongated flame openings.
  • the jets flowing out from different openings don't join together before the jet velocity becomes equal to the combustion velocity at the given conditions of mixture and temperature; in this case and in case of single mixture jet expressly supplied secondary air, pure or mixed with recycled mixture, is sucked into said jet/s just down stream the flame opening increasing locally the ⁇ of the mixture up to 30% and the fluids dynamic obstacle must closely follow the shape of the related opening.
  • the body/s forming the obstacle need to have the centreline of the assembly or of the body in the centre, or slightly out of the centre (for instance when near the side walls of the combustion chamber) of the mixture jet in the observed point.
  • the distance obstacle opening and its shape may vary along the opening length to follow flow-rate changes along said opening or to obtain particular flame shapes to comply with the heat exchanger. The position of said obstacles follow the flame openings surface.
  • the position of the flame as the distance between the barycentre of the flame front and the surface of at least one flame opening which generates this front, hereafter said quantity will be called flame distance.
  • the aeration ratio ⁇ of the mixture remain stable but flow-rate decreases (the exit velocity decreases), the flame distance decreases and vice-versa if the flow rate increases.
  • the flame distance optimum value can generally be predetermined arbitrary constant, but can have different values according to the fuel-gas flow rate; in any case, during the on periods on the combustion system, the instantaneous ratio, which is the detected flame distance/optimum flame distance, have the value -1- for the reached conditions considered as optimum, values over 1 show the tendency to the flame blow-off increasing as the ratio increases, values under 1 show the tendency to overheat the burner head (means the flame openings zone) increasing as the ratio decreases.
  • the instantaneous ratio detected flame distance/optimum flame distance, will be hereafter called flame ratio.
  • the modification on the flame distance will cause a change of the cross section of the obstacle changing the flow conditions on the side of said obstacle and therefore shape of the flame, for example: bimetal or sealed bulbs filled with expansible fluid can be used.
  • the outflow cross-section of the flame opening/s is varied according to the flame ratio, between a minimum and a maximum cross-section, causing a flame ratio > 1 an outflow section increase and vice versa, so as to maintain the flame ratio around a pre-fixed value, except for a different regulation during the transient periods, for example of starting, when needed.
  • the distance of a V shaped obstacle can be varied in such a way that the vertex of the V would enter the flame opening reducing the open surface.
  • the temperature of the mixture outflow zone of the burner head remains within acceptable limits (even below 200 °C), at any capacity condition of the burner, type of feeding gas, temperature of the inlet air; the flame remain stable; the harmful emissions are reduced to minima values.
  • FIG. 1 shows, in vertical cross section, a combustion system 1 with a heat exchanger 2, a combustion chamber 3, a fan 4 for the air gas and exhausts circulation, put upstream the combustion chamber for which this is in over pressure compared to the outside of shell 5 representing the body of the combustion system, which, in this case, is a water cooled aluminium casting, whose inferior part forms the burner head 6 and the burner body 8, inside which a distributor 8C is installed; flame openings 7B obtained from the aluminium casting have lips, are lengthened, perpendicularly to the drawing surface.
  • the process controller 15 according to the signals transmitted by the ionisation current sensor 14A operates the fuel gas valve 11 and the fan 4 speed.
  • FIG. 2 shows, in vertical cross section a combustion system operating in forced draft with the fan 4 mounted downstream the heat exchanger 2 so the inside of the shell 5 is in depression compared to the outside.
  • the burner the body 8 of which is the bottom part of the shell 5
  • the air-fuel gas mixture is obtained in a Venturi type tube 10 from the fuel gas exiting the injector 23 and the air from outside the shell 5 entering the mouth 9.
  • the mixture is drawn through the Venturi 10 and the mixing chamber to the flame openings 7A, better described in fig. 15, 16, obtained on the sheet metal, for example, of 0.4-0.6 mm thickness, of the burner head 6.
  • the flame openings 7A each made of a row of slots, where the slots are 0.5 to 0.75 mm. width and 5 to 15 mm. long, parallel to each other on the long side with centre distance between 0.9 and 1.5 mm., rows are spaced centre to centre from 15 to 60 mm to obtain a flying carpet type lamellar flame 19 anchored to external obstacles 12B, made on stainless steel sheet metal, visible in V shaped cross section with upstream vertex and centreline of the V, perpendicular to the surface and in centre of the flame openings, parallel to the rows and distant to the slot surface from few to some ten mm according to the exit velocity of the mixture, V shaped obstacles of this type are better described in fig 7, 8, 9.
  • the distance among flame openings and shape and position of the obstacles don't permit any recycling of exhaust gases, therefore the jets down stream the burner head surface suck only recycled air gas mixture.
  • the lamellar flame covers the plan of the combustion chamber 3, lying at level of the optical sensor 14B.
  • the process controller not shown, varies the gas flow through the valve 11, according to the heat request.
  • the optical device 14B based on photo sensor/s, transmits a signal corresponding to the detected position of the flame to the process controller, not shown, which compares said position to a pre-fixed one (flame ratio), in order to change the fan speed.
  • FIG. 3 shows a natural draft combustion system 1, which employs a partially premixed atmospheric burner with body 8A of the extractable type; the secondary air is introduced from the inlet openings 18 on the shell 5.
  • Flame openings 7A are formed of rows (perpendicularly lengthened to the drawing) of slots as in fig.2, 15, 16, punched on burner head 6;
  • the external fluids dynamic obstacles have a V shaped cross section, as in fig.2, but made from bimetallic sheets cut and bent as described in fig.15, 16, 17.
  • the flame Being the centre distance among exits 7A big, the flame, ignited by a device not seen, divides itself in long separate V shaped lamellar flames 19A (perpendicularly lengthened to the drawing), at the same time the secondary air, introduced through the apertures 18, is sucked from the mixture jets just down stream the flame opening increasing the ⁇ of the mixture up to 30%.
  • the ignition is obtained from the heat element 14 and the flame presence is controlled by a thermocouple not shown.
  • FIG.4 show a natural draft combustion system with partially premixed atmospheric burner, without any specific process control.
  • the burner head 6 is of perforated sheet metal having the circular holes diameter from 2 to 5 mm. and lips from 1.5 to 7 mm. high.as better described in fig. 10, 11, uniformly positioned on the burner head as in fig. 11, so spaced each other to obtain a ratio open/total surface between 0.2 and 0.5 as to form a single substantially homogeneous mixture jet and to build a carpet shaped lamellar flame 19 anchored to a mesh net fluids dynamic obstacle 13 B, been the net made of wires of high nickel steel, regularly distributed to cover more/over the complete flame openings surface.
  • a combined device 14 A which is an ionisation current sensor also capable to cause the spark ignition.
  • FIG. 5 shows an atmospheric burner with tubular body 8A with a sole flame opening 7B between two lips, with an external fluids dynamics obstacle having a triangle cross section positioned with the central line on centreplane of the burner at a distance from the flame opening edges up to 10 times the width of said flame opening with a cross dimension of the same magnitude of said width, anchoring the large V shaped flame.
  • the fluid dynamics obstacle, of triangle section ceramic rod, is supported (the support is not shown) on the extremities leaving the possibility of expansion.
  • FIG. 6 shows the atmospheric burner of fig. 5 in vertical cross section to better understand the reciprocal dimension and position of the flame opening in this particular case.
  • FIG. 7 shows a tubular atmospheric burner with the body 8A forming a sole flame opening 7B with two mobile lips 7B2, which define the outflow cross section of it, moved by the deformation (temperature function of the flame opening edges) of two bimetallic sensors-actuators 17.
  • the lips 7B2-a position full line drawn and 7B2-b the dashed drawn one correspond to two different conditions of the flame opening temperature obviously higher the one corresponding to the dashed line, the same for the position 17-a and 17-b of the bimetallic arches;
  • the cross section of the burner body 8A is similar to that of fig.5 but the external obstacle have a V shaped cross section 12B.
  • FIG. 8 and 9 show the vertical cross sections of the tubular burner of fig. 7 in the two different operating conditions, shown with dashed and continuos lines for the same conditions represented there in the same way.
  • FIG. 10 shows, on plan view from the top, round holes having an external lip around, punched on sheet metal, arranged in groups of three holes in line, the groups parallel and so near to each other, forming a row which is one flame opening 7C, in fact the mixture exiting from all the slots of a row form a sole jet, the three rows shown have centre distance as in fig. 3 to obtain separate V shaped flames; dimensions of the holes are as defined in fig. 4.
  • the projection of external trilobated elongated obstacles 12D are shown with dashed lines.
  • FIG. 11 shows, on plan view from the top, round holes having an external lip around, punched on sheet metal as those shown in fig.10 disposed regularly and close together, with a ratio open /total surface around 30%, jets flowing out from the flame openings are separate and join together around the level of the trilobated obstacles 12D, but because in this case the centre distance of said external fluids dynamic obstacles (projection is shown in dashed line), is big enough, a flame shaped alike a wave flying carpet is obtained, similar to that of fig. 1 obtained with a different lay out of flame openings and obstacles.
  • FIG.12 shows the vertical section of two aligned elongated openings so close together that a sole obstacle (12C), in this case a bimetallic V shaped one, the vertex is near the flame openings surface.
  • a sole obstacle (12C) in this case a bimetallic V shaped one
  • the vertex is near the flame openings surface.
  • Any variation of the form and or position of the flame cause a change of the cross section obstacle such to tend to re-establish the previous conditions, particularly at any increase of the flame distance causes an increase of the transversal dimension of the obstacle (12C) cross section, the opposite for a reduction. Also the flame and the wall design is visible.
  • FIG. 13 shows an enlarged plan view of the burner head in a first level where are visible slots parallel each other combined in groups of three and four, these said groups (the flame openings) been distributed in a check pattern to obtain a flying carpet shape lamellar flame 19 in the second level the external obstacle is visible formed of a net 13C made of parallel ceramic rods in one direction and wires perpendicularly, regularly covering the combustion chamber plan.
  • FIG. 14 shows the vertical section corresponding with the application of fig. 13 where the reciprocal position of openings, obstacle and flame are visible.
  • FIG. 15 shows the vertical section C-C of fig. 16 where the reciprocal position of openings, obstacle and flame are visible.
  • the composition of the gaseous content from the volume surrounding the jet sucked, immediately down stream the flame opening, inside said jet is a mixture of secondary air and recycled exhaust gases in different ratio following different operating conditions.
  • FIG. 16 is a top view in two levels, of a part of the burner's head 6 of fig.3, two flame openings are represented, made of a row each of parallel slots having width from 0.5 to 0.75 and length from 5 to 15 mm. adjacent on the long side, spaced centre to centre from 0.9 to 1.5 mm., the external bimetallic obstacle 12C V shaped is visible on the left side on the second level.
  • FIG. 17 show the plan view of part of a sheet metal rectangle with alternate parallel cuts which bent would form the V shaped obstacle of fig.3, 12, 15, 16, the cuts are foreseen to prevent arc formed bending of the obstacle caused by the temperature distribution during the heating periods of the combustion system, if the sides of the V are longer than some mm. and the total length of the obstacle more than about 100 mm.
  • FIG.18 shows a forced draft combustion system, the burner, the body 8A of which is bottom part of the shell 5, the air-fuel gas mixture is obtained in a Venturi type tube 10 from the fuel gas exiting the injector 23 and the air from outside the shell 5 entering the mouth 9.
  • An optical device 14B is used to detect the flame ratio as to permit to the controller 15 the variation of the outflow velocity of the mixture according to said flame ratio using a step by step motor 25 moving up and down the obstacles 13A through an eccentric 28 as better described in fig 19 and 20.
  • the flame openings 7B, lips formed, are lengthened, perpendicularly to the drawing surface; on the centre axe of the jet out flowing from said openings 7B, inside the combustion chamber 3, at a variable distance, from the flame openings surface, parallel to the openings, are disposed (displaced) fluids dynamic obstacles, V shaped made of stainless steel sheet metal 12Aa, supported each by a ceramic rod 12Ab,; the openings and the obstacles have the same length.
  • FIG. 19 shows the vertical section A-A of fig. 18, looks clear how the eccentric 28 moved by the motor 25 can push down the obstacles 12A against the springs 30 actuating the desired changes of the cross section of the flame openings 7B visible in fig. 18 and 20.
  • FIG. 20 shows a vertical section of lips formed flame opening 7B with movable obstacle 12B which modify the outflow cross-section of the flame opening and therefore the outflow velocity, according to the flame ratio, between a minimum and a maximum cross-section, causing a flame ratio > 1 an outflow section increase and vice versa, so as to maintain the flame 19A distance around a pre-fixed value, except for a different regulation during the transient periods, for example of starting, when needed.
  • Two position of the obstacle and that correlate of the flame, are shown, with dashed line 12B-a the one for smaller outflow cross-section continuos line 12B-b those for higher.

Landscapes

  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Gas Burners (AREA)

Claims (15)

  1. Méthode de combustion, dans un system de combustion soit a convection naturelle soit mécanique, avec les passages suivant:
    a- un brûleur pré mélangé, atmosphérique or forcé réalise en mélange de air et gaz combustible de presque stçchiométrique a fortement iperstçchiometrique,
    b- le mélange coule, dans la chambre de combustion, par au moins une ouverture de flamme avec une distribution de vitesse telle d'obtenir une écoulement substantiellement laminaire.
    c- Un seul jet de mélange substantiellement homogène sorts de chaque sortie de flamme et, immédiatement en aval de cette sortie, le contenu gazeuse de la volume qui enveloppe le jet est absorbé dans cette jet et mélanger la dedans.
    d- Au moins, une obstacle fluidodynamique est immerger dans le jet qui coule dehors, en aval d'au moins une ouverture de flamme, détacher de cette ouverture, dans une position où la vitesse de le mélange air gaz combustible est dans chaque point de le jet, plus grand que la vitesse de combustion, dans toutes les conditions du travail.
    e- Une zone de stagnation est crée à cause de la forme est de les dimensions de l'obstacle, en aval de cette obstacle fluidodynamique.
    f- Un écoulement presque laminaire est produit avec des filets fluides progressivement divergent à coté de l'obstacle fluidodynamique
    g- Une flamme de laminaire à rider, laquelle est au début allumé par un appareil spécifique, est produit et ancré dans toutes les conditions de travail à cause des vorticelles liées à la zone de stagnation, au moins dans quelques points.
    Par où
    La vitesse du jet de mélange coulant de chaque sortie de flamme restes supérieure à 0.4 m/sec dans toutes les conditions de travail,
    Dans le cas d'une seule jet de mélange ou dans le cas dont les différents jets de mélange ne se joindrent pas avant le front de flamme, de l'air secondaire, pure ou mélanger avec de mélange recyclé, est aspirer dans cette jet/s juste en aval de l'ouverture de flamme augmentant localement λ du mélange jusqu'à 30%.
    Si les jets de mélange joindrent ensemble avant le front de flamme, surtout le mélange recyclé, est aspiré dans cette jet/s, juste en aval de l'ouverture de flamme
    Les filets fluides du écoulement pratiquement laminaire sont progressivement divergents aussi en aval de l'obstacle fluidodynamiques,
    Par où
    • la flamme de laminaire à rider, caractérisé par un large surface et une épaisseur très bas, ne touche pas absolument la surface de la sortie de flamme.
  2. Méthode suivant la revendication 1, où la composition du contenu gazeuse absorbé de la volume qui enveloppe le jet, est une mélange de air secondaire et air/gaz mélange recyclé, en pourcentage différent suivant les différents conditions de travail.
  3. Tête d'une brûleur pré mélangé, atmosphérique or forcé, avec un appareil spécifique d'allumage, capable de réaliser la méthode de la revendications 1 ou 2,
    Laquelle a le/s ouverture/s de flamme qui couvrent partiellement la surface de cette tête de brûleur,
    Laquelle a au moins une obstacle fluidodynamiques avec une section de la forme circulaire à la forme V, positionné en aval de au moins une sortie de flamme immergé dans le jet de mélange qui sort pour créer en aval une zone de stagnation, laquelle cause l'anchorage de la flamme dans toutes les conditions de travail,
    Cette obstacle fluidodynamique est, dans tout les cas séparer et complètement détacher de cette au moins un sortie de flamme, la distance entre cette sortie et le point plus loin de l'obstacle en étant au moins si grand que la largeur de la sortie de flamme,
    La largeur de la section de l'obstacle en étant de le même ordre de grandeur de la largeur de la sortie de flamme plus près, l'obstacle en étant forme et dimension capable de créer en aval une zone de stagnation qui cause l'anchorage de la flamme dans toutes les conditions de travail.
    Par où
    La surface et la forme de/s sortie/s de flamme sont tels que: dans toutes les conditions de travail, la vitesse du jet qui coule dehors est plus grand de 4m/sec, pour au moins une distance égale à celle d'au moins un obstacle fluidodynamique,
    La surface et la forme d'au moins un obstacle fluidodynamique, ensemble avec la surface et la distribution de la sortie de flamme (vitesse et distribution de la vitesse du jet), sont tels pour obtenir, une écoulement presque laminaire en avant filets fluides divergents en aval et à coté de l'obstacle/s, en obtenant une flamme de laminaire à rider qui ne touche pas du tout les sorties de flamme, caractérisé par une large surface et une épaisseur très bas.
    Dans le cas où
    La tête du brûleur est de type complètement pré mélangé et les sorties de flamme de la tête de brûleur sont distribuées l'une près de l'autre et distribuées d'une façon homogène, le contenu gazeuse de la volume qui enveloppe le jet immédiatement en aval de la sortie de flamme, aspiré dans cet jet, est surtout mélange air/gaz recyclé,
    Dans le cas où
    La tête du brûleur est de type partiellement pré mélangé et des passages d'air secondaire sont prévues, l'obstacle/s fluidodynamiques suive le/s sortie/s de flamme lesquelles sont homogènement distribuées sur la surface, mais dans cet cas élongées l'une l'autre, le contenu gazeuse de la volume qui enveloppe le jet immédiatement en aval la sortie de flamme, aspiré dans cet jet, est air secondaire pure ou mélangé avec mélange d'air/gaz recyclé.
  4. Tête de brûleur suivant la revendication 3 caractérisé pour le fait que les sorties de flamme et les obstacles fluidodynamiques extérieurs sont près l'un à l'autre et distribués en façon homogène tel de obtenir une seule flamme détachée de les sorties de flamme, qui couvre toute la surface de celles.
  5. Tête de brûleur suivant la revendication 4 caractérisé pour le fait que l'obstacle extérieur est une grillage régulièrement distribuée sur l'entier surface de les sortie/s de flamme suivant la forme de cette surface.
  6. Tête de brûleur suivant la revendication 4 caractérisé pour le fait que l'obstacle est construit de tiges régulièrement distribuée sur l'entier surface de les sortie/s de flamme suivant la forme de cette surface.
  7. Tête de brûleur suivant la revendication 3 caractérisé pour le fait que l'obstacle/s, est/sont strictement lié/es à la/les sortie/s de flamme, suivant la forme de cette/s sortie/s de flamme.
  8. Tête de brûleur suivant la revendication 7 caractérisé pour le fait que l'obstacle/s ont tout les points l'axe de symétrie dans l'axe central de le jet de mélange qui coule dans cet point.
  9. Tête de brûleur suivant la revendication 3 avant l'obstacle extérieur fluidodynamique caractérisé par le fait que la section de l'obstacle fluidodynamique a un arête même aiguisé en amont pour diviser le jet de mélange sans créer stagnation.
  10. Tête de brûleur suivant la revendication 3 à 9 caractérisé pour le fait que chaque augmentation de la distance de la flamme cause une augmentation de la dimension transversale de l'obstacle, l'opposé pour une réduction.
  11. Tête de brûleur suivant la revendication 9 et 10 caractérisé pour le fait que l'obstacle/s est une ampoule allongé étanche, rempli par une liquide expansible.
  12. Tête de brûleur suivant la revendication 9 et 10 caractérisé pour le fait que l'obstacle/s est une profile bimétallique à forme V.
  13. Tête de brûleur suivant la revendication 3 caractérisé pour le fait que l'obstacle/s extérieur est construit par une matériel résistante à une température supérieure à 500 degrés.
  14. Méthode suivant une ou plusieurs de les revendications 1 et 2, caractérisé par le fait que chaque variation de la flamme ratio provoque le changement de la section de passage de la sortie de flamme, une augmentation pour flamme ratio >1, une diminution pour flamme ratio <1, entre un minimum et un maximum de section de passage qui coïncide avec le minimum et le maximum de la puissance de le brûleur.
  15. Tête de brûleur suivant le méthode de la revendication 14 caractérisé par le fait que le mouvement de l'obstacle fluidodynamiques extérieur change la surface ouverte de la sortie de flamme.
EP97954925A 1996-12-18 1997-12-18 Ancrage d'une falmme laminaire de combustible gazeux Expired - Lifetime EP0956476B1 (fr)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
ITMI962653 1996-12-18
IT96MI002653A IT1289459B1 (it) 1996-12-18 1996-12-18 Metodo ed apparecchi per ottenere fiamma stabile,distaccata dalla testa del bruciatore,per miscele iperstechiometriche gas-aria
PCT/EP1997/007119 WO1998027386A1 (fr) 1996-12-18 1997-12-18 Ancrage d'une flamme laminaire de combustible gazeux

Publications (2)

Publication Number Publication Date
EP0956476A1 EP0956476A1 (fr) 1999-11-17
EP0956476B1 true EP0956476B1 (fr) 2002-11-13

Family

ID=11375420

Family Applications (1)

Application Number Title Priority Date Filing Date
EP97954925A Expired - Lifetime EP0956476B1 (fr) 1996-12-18 1997-12-18 Ancrage d'une falmme laminaire de combustible gazeux

Country Status (4)

Country Link
EP (1) EP0956476B1 (fr)
DE (1) DE69717152D1 (fr)
IT (1) IT1289459B1 (fr)
WO (1) WO1998027386A1 (fr)

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6729874B2 (en) 2000-07-27 2004-05-04 John Zink Company, Llc Venturi cluster, and burners and methods employing such cluster
FR2835906B1 (fr) * 2002-02-13 2004-06-04 Saint Gobain Isover Bruleur a combustion interne, notamment pour l'etirage de fibres minerales

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB8319620D0 (en) * 1983-07-20 1983-08-24 British Petroleum Co Plc Burner
GB9025787D0 (en) * 1990-11-27 1991-01-09 Baxi Partnership Ltd Gas-fired appliances
AT396020B (de) * 1991-01-25 1993-05-25 Vaillant Gmbh Gasbrenner
IT1283699B1 (it) * 1996-03-25 1998-04-30 Enrico Sebastiani Regolazione della velocita'di efflusso della miscela aria-gas dalle uscite di fiamma di bruciatori a gas

Also Published As

Publication number Publication date
IT1289459B1 (it) 1998-10-15
ITMI962653A1 (it) 1998-06-18
DE69717152D1 (de) 2002-12-19
ITMI962653A0 (it) 1996-12-18
WO1998027386A1 (fr) 1998-06-25
EP0956476A1 (fr) 1999-11-17

Similar Documents

Publication Publication Date Title
CN113557390B (zh) 操作可调节的燃烧器的方法
US6113384A (en) Regulation of gas combustion through flame position
CA2558136C (fr) Four a bruleurs multiples muni d&#39;un dispositif de commande de variation de debit perfectionne
EP0695911A1 (fr) Brûleur à gaz avec un diffuseur amélioré
US9885476B2 (en) Surface combustion gas burner
EP3295083B1 (fr) Brûleur à élément de distribution d&#39;écoulement
US5685708A (en) Fuel fired burners
JPH0246842B2 (fr)
EP0956476B1 (fr) Ancrage d&#39;une falmme laminaire de combustible gazeux
US4237858A (en) Thin and flat flame burner
US20020132198A1 (en) Gas burner
US5562440A (en) Gas burner with radiant retention head
US7410288B1 (en) Fluid mixing device
US3361367A (en) Gas burner
GB2404001A (en) Heating means for a drying apparatus
US8021145B2 (en) Gas burners
US3405921A (en) Air-heating gas burner
US5762490A (en) Premixed gas burner orifice
EP1083386A1 (fr) Assemblage de brûleurs et tête ascociée pour la combustion de mélanges gazeux
JP3561905B2 (ja) 燃焼装置
WO1995009326A1 (fr) Procede et dispositif de combustion de gaz
CN218672170U (zh) 用于燃烧器的火排、燃烧器和热水器
CN218672169U (zh) 用于燃烧器的火排、燃烧器和热水器
JPS6143057Y2 (fr)
JP2008185287A (ja) 濃淡燃焼バーナ

Legal Events

Date Code Title Description
PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

17P Request for examination filed

Effective date: 19990622

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): DE ES FR GB IT NL

17Q First examination report despatched

Effective date: 20000315

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAG Despatch of communication of intention to grant

Free format text: ORIGINAL CODE: EPIDOS AGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAH Despatch of communication of intention to grant a patent

Free format text: ORIGINAL CODE: EPIDOS IGRA

GRAA (expected) grant

Free format text: ORIGINAL CODE: 0009210

AK Designated contracting states

Kind code of ref document: B1

Designated state(s): DE ES FR GB IT NL

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: NL

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20021113

Ref country code: IT

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT;WARNING: LAPSES OF ITALIAN PATENTS WITH EFFECTIVE DATE BEFORE 2007 MAY HAVE OCCURRED AT ANY TIME BEFORE 2007. THE CORRECT EFFECTIVE DATE MAY BE DIFFERENT FROM THE ONE RECORDED.

Effective date: 20021113

Ref country code: FR

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20021113

REG Reference to a national code

Ref country code: GB

Ref legal event code: FG4D

REF Corresponds to:

Ref document number: 69717152

Country of ref document: DE

Date of ref document: 20021219

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: GB

Free format text: LAPSE BECAUSE OF NON-PAYMENT OF DUE FEES

Effective date: 20030213

PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: DE

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20030214

NLV1 Nl: lapsed or annulled due to failure to fulfill the requirements of art. 29p and 29m of the patents act
PG25 Lapsed in a contracting state [announced via postgrant information from national office to epo]

Ref country code: ES

Free format text: LAPSE BECAUSE OF FAILURE TO SUBMIT A TRANSLATION OF THE DESCRIPTION OR TO PAY THE FEE WITHIN THE PRESCRIBED TIME-LIMIT

Effective date: 20030529

EN Fr: translation not filed
PLBE No opposition filed within time limit

Free format text: ORIGINAL CODE: 0009261

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: NO OPPOSITION FILED WITHIN TIME LIMIT

GBPC Gb: european patent ceased through non-payment of renewal fee
26N No opposition filed

Effective date: 20030814