EP0970325B1 - Premix burner with a flow rate of more than 1000 litres/hour - Google Patents

Premix burner with a flow rate of more than 1000 litres/hour Download PDF

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Publication number
EP0970325B1
EP0970325B1 EP98914950A EP98914950A EP0970325B1 EP 0970325 B1 EP0970325 B1 EP 0970325B1 EP 98914950 A EP98914950 A EP 98914950A EP 98914950 A EP98914950 A EP 98914950A EP 0970325 B1 EP0970325 B1 EP 0970325B1
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EP
European Patent Office
Prior art keywords
flow
feed pipe
section
burner according
cross
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
EP98914950A
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German (de)
French (fr)
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EP0970325A1 (en
Inventor
Jean-Marie Truffaut
Geoff IRPHE UMR 6594 CNRS SEARBY
Louis IRPHE UMR 6594 CNRS BOYER
Gilles Cannet
Francis Briand
Philippe Pisot
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Lincoln Electric Co France SA
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La Soudure Autogene Francaise
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    • 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
    • F23D14/38—Torches, e.g. for brazing or heating
    • 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
    • F23D14/08—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 axial outlets at the burner head
    • 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 a burner, such as a torch, of preferably monodard, with premix of flow rate greater than 1000 l / h of the type comprising a gas mixture supply pipe having a supply end of the gas mixture and a single nozzle for the establishment of the flame mounted at the other end of said pipe feed.
  • Burners, in particular torches, in particular of the type known premix monodard generally have at the end supply an injector ensuring the contacting of a gas fuel, from a first power source, with a gas oxidizer, from a second power source (see for example FR-A-322 011, US-A-4 886 447).
  • the supply line thus connects the injector to the nozzle.
  • This pipe is generally formed by a straight pipe on the essential of its length, commonly called a lance.
  • the spear is about 30 cm long. In practice, the spear has a bend at its outlet end.
  • the invention aims to provide a burner, in particular a torch, whose noise emissions caused by the flame are reduced.
  • the subject of the invention is a burner, such as a torch, of preferably monodard, with premix of flow rate greater than 1000 l / h of the type above, characterized in that the supply line is adapted for that at any point of at least one cross section thereof, the Reynolds number of the mixture flowing in the supply line is less than 3000, when the burner or torch operates in steady state at a flow rate greater than 1000 l / h.
  • the burner according to the invention is a torch, such as a monodard torch.
  • the invention also relates to the use of a torch according to the invention in an oxy-combustion process, putting using a mixture containing at least one combustible gas and at minus an oxidizing gas, such as a mixture containing oxygen and propane.
  • a monodard torch according to the invention can be applied to any brewing operation, from warm before removal ("straightening" in English), preheating before welding, heating for forming or any other processing operation thermal of a material preferably a metal or alloy material metallic.
  • the burner according to the invention can be applied to the combustion field, i.e. any process using an oxy-fuel flame, for example in an oven and / or in the glass working.
  • oxygen is the preferred oxidizer, it is possible to also, in some cases, use air, preferably compressed, as an oxidizing gas.
  • the torch 10 shown in Figure 1 includes an injector premix 12, a lance 14 forming a supply line for the mixture and a single end nozzle 16.
  • the injector 12 comprises a body 18 crossed by a conduit fuel gas supply 20.
  • the body 18 further comprises a side duct 22 for supplying oxidant gas.
  • the conduits 20 and 22 open into a threaded hole 24, into which a manifold 26 is screwed through through an axial passage 28 for feeding the gaseous mixture into the conduit 14.
  • the passage 28 has a diameter of approximately 3 mm and is connected to the conduits 20 and 22 by connections 30.
  • the passage 28 opens at the center of a flat transverse face of the collector, denoted 28A, which extends perpendicularly to the passage axis 28.
  • the pipe 14 is formed by a pipe of circular section having an internal diameter equal to approximately 21 mm and a length equal to 276 mm approx.
  • An inlet end 32 of the pipe 14 has a thread outside. It is screwed into the threaded hole 24. This end rests on the flat face 28A.
  • Line 14 includes, at the supply end 32, a open mixing chamber 34 into which the feed passage 28.
  • the section of the mixing chamber 34 is equal to the inner section of the pipe 14. This section is very greater than the section of the passage 28.
  • the section of the pipe supply increases suddenly according to the direction of flow of the mixed. This brutal variation in section is ensured here by a shoulder delimited by the face 28A.
  • the pipe 14 contains successive organs for regulating the gas flow spaced apart by clear sections.
  • a baffle 36 is arranged downstream of the end inlet 32. This defines with the flat face 28A of the injector the mixing chamber 34 which extends over 21 mm.
  • Chicane 36 is formed by an agglomerated set of elements analogues, for example independent balls 36A retained between two transverse end grids 36B.
  • 36A balls have a diameter 4 mm.
  • 36B grids consist of a braided wire mesh whose neighboring strands are spaced about 0.5 mm apart.
  • This baffle can also be formed by a porous material, in particular a sintered material.
  • the baffle 36 extends over a length of 30 mm. She is followed by an unobstructed tranquilization chamber 38 also extending over a length of 30 mm.
  • Chamber 38 is delimited downstream by a guide member 40 axial flow.
  • This organ is formed by a section with a length 24 mm, of a honeycomb structure whose walls extend along the axis of the pipe 14.
  • the member 40 is formed of an assembly of longitudinal walls dividing the pipe 14 into a set of parallel channels. The diameter of each channel is 4 mm.
  • the channels here have a hexagonal section. However, they can also be square or circular section.
  • a second chamber Downstream of the member 40, a second chamber is provided. still 42 extending over a length of 85 mm. She is delimited at its downstream end by a second axial guide member 44 formed by a honeycomb structure whose diameter of each channel is equal to 1 mm. This organ 44, the channels of which extend along the direction of flow, has a length of 6 mm.
  • a grid 46 Downstream of the member 44 is disposed a grid 46, the mesh of which is about 0.5 mm. This grid delimits with the organ 44 a room released from stilling 48 extending over 50 mm.
  • the grid 46 is separated from the outlet end of the pipe 14 by an open chamber 50 extending over 30 mm.
  • the nozzle 16 has an inner profile of revolution. It is delimited from line 14 to its outlet end 52 via a converge 54 having a general profile in S. Convergent 54 is tangentially connects to the outlet end of the pipe 14. The outlet end 52 of the nozzle has a diameter of 3 mm, so that the nominal mixing flow rate of such a nozzle is 2000 l / h.
  • the profile of the convergent 54 is for example defined by a polynomial of order 5 calculated according to the Bell and Metha method, described in publication "Bell, J.H. and Metha, R.D. Contraction Design for Small Low Speed Wind Tunnels, AIAA Journal, 27, 372-4, (1989) ".
  • This nozzle has a great contraction ratio.
  • the contraction ratio which is defined by the inlet section of the nozzle on its outlet section is approximately 50. From plus, the aspect ratio, i.e. the length of the nozzle over its diameter input is about 2.6.
  • the surface of the convergent 54 is chosen to be as smooth as possible.
  • the nozzle 16 is connected to the end of the pipe 14 by a threaded connection sleeve 56.
  • the positioning devices and for fixing members 36, 40, 44 and 46 constituted for example by tubular sections forming spacers between the members, are adapted to ensure the continuity of the inner wall of the lance, so that it is internally devoid of roughness, groove and variation abrupt section.
  • the pipe 14 of the torch described here has a section interior of large area compared to that of the outlet section of the nozzle.
  • the Reynolds number of mixture flowing in line 14 is at least one pipe cross-section less than 3000, when the torch operates in steady state.
  • the speed in the pipe is substantially equal to 2 m / s, which gives a Reynolds number substantially equal to 2000 in the cleared sections 38, 42, 48, 50 of the tube.
  • the flow of the gas mixture in the supply line is a substantially laminar flow.
  • Figure 2 presents experimental results of measurements of the noise level.
  • Noise levels were raised 0.5 m from the nozzle in the exit plan from it.
  • the reference levels have been obtained with a "Varial G2" type torch, sold in France by French Autogenic Welding. This torch was equipped a nozzle with a nominal mixing flow of 2000 l / h having a diameter 3 mm outlet.
  • the richness of the mixture used, propane and oxygen, was 1.33.
  • the inner diameter of the pipe cylindrical feed of such a torch is 8 mm.
  • the curve shows the sound levels recorded for this torch reference and the torch 10 of FIG. 1, for different flow rates ranging from 1200 l / h to 3000 l / h of the same mixture. These sound levels are represented respectively by black circles and white squares.
  • the noise emitted by a flame comes on the one hand from the sting (part central flame) and on the other hand the plume (peripheral part of the flame).
  • the torch according to the invention was designed in order to further reduce the turbulence present at the base of the sting.
  • the torch has been sized to obtain a substantially laminar flow inside the lance.
  • the combustible and oxidizing gases are brought into contact in the feed passage 28.
  • the sudden change in diameter at the end inlet 32 causes gas recirculation inside the chamber 34.
  • eddies arise at the exit from passage 28, which creates a turbulent flow in the chamber 34. This turbulent flow promotes the homogeneous mixing of gas.
  • the variation should from section from section of passage 28 to maximum section of the mixing chamber takes place over a short length along the axis of the pipe 14.
  • the profile must be understood on the outside a cone whose angle at the top is equal to 14 ° and preferably greater than or equal to 20 °.
  • the length of the mixing chamber is advantageously equal the diameter of the latter.
  • the flow of combustible and oxidizing gases mixed in the room 34 then flows randomly through the chicane 36.
  • the spatial scale of turbulence is thus reduced to one dimension on the order of the diameter of the balls 36A (4 mm).
  • the stilling chamber 38 then ensures a viscous dissipation of the vortices still present in the flow.
  • the axial guide member 40 then ensures attenuation of the fluctuations in transverse velocities in the flow. In particular, it directs the flow in the direction of the axis of the pipe 14.
  • the length of the member with a nest structure bee is four to ten times and preferably six to eight times the diameter of the channels constituting said organ.
  • the stilling chamber 42 arranged downstream of the member 40, must have a length sufficient to absorb the turbulence generated by the member 40.
  • the member 44 ensures with the downstream stabilization 48 a new reduction in speeds transverse in the flow and improves the directivity of the flow.
  • the grid 46 associated with the chamber 50 performs a damping final turbulence of the flow.
  • baffle 36 and the guide members axial flow 40, 44 further improves the reduction in the level of noise.
  • FIG 3 an alternative embodiment of the torch 10 in Figure 1.
  • This torch is indistinguishable from that of the Figure 1 only by its supply line.
  • This is formed by a tube 100 of circular section with internal diameter equal to 10 mm and of length equal to 221 mm.
  • This tube has two internal parts identical 102, 104 for axial guidance of the mixture.
  • These organs are formed by honeycomb structures whose walls extend longitudinally. These walls delimit channels of diameter equal to 1 mm.
  • These two sections 102, 104 each extend over a length 60 mm. They define between them a tranquilization chamber open bearing the reference 106. This extends over a length of 30 mm.
  • a chamber still 108 extending over a length of 50 mm.
  • a flow of the order about 2800 l / h leads to a speed in the supply line equal to 10 m / s.
  • the Reynolds number of the mixture flowing in the parallel channels bounded by the honeycomb structures is substantially equal to 500.
  • the Reynolds number of the flow is less than 3000 over the entire section of the pipe. This causes laminarization of the flow from which it results improved stabilization of the flame dart.
  • the torch described in Figure 3 generates a noise level significantly lower than the reference torch.
  • the torches described here have a straight lance. However, this may include a bent section (in particular at its output end), without the measured noise level being significantly increased.

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

Description

La présente invention concerne un brûleur, tel un chalumeau, de préférence monodard, à prémélange de débit supérieur à 1000 l/h du type comportant une conduite d'alimentation en mélange gazeux ayant une extrémité d'alimentation du mélange gazeux et une buse unique pour l'établissement de la flamme montée à l'autre extrémité de ladite conduite d'alimentation.The present invention relates to a burner, such as a torch, of preferably monodard, with premix of flow rate greater than 1000 l / h of the type comprising a gas mixture supply pipe having a supply end of the gas mixture and a single nozzle for the establishment of the flame mounted at the other end of said pipe feed.

Les brûleurs, en particulier les chalumeaux notamment de type monodard à prémélange connus comportent généralement à l'extrémité d'alimentation un injecteur assurant la mise en contact d'un gaz combustible, issu d'une première source d'alimentation, avec un gaz comburant, issu d'une seconde source d'alimentation (voir p. ex. FR-A-322 011, US-A-4 886 447).Burners, in particular torches, in particular of the type known premix monodard generally have at the end supply an injector ensuring the contacting of a gas fuel, from a first power source, with a gas oxidizer, from a second power source (see for example FR-A-322 011, US-A-4 886 447).

La conduite d'alimentation relie ainsi l'injecteur à la buse. Cette conduite est généralement formée par un tuyau rectiligne sur l'essentiel de sa longueur, communément appelé lance. Pour un chalumeau à mains, la lance a une longueur d'environ 30 cm. Dans la pratique, la lance comporte un coude à son extrémité de sortie.The supply line thus connects the injector to the nozzle. This pipe is generally formed by a straight pipe on the essential of its length, commonly called a lance. For a blowtorch hands, the spear is about 30 cm long. In practice, the spear has a bend at its outlet end.

Afin d'éviter les retours de flamme à l'intérieur de la conduite d'alimentation et limiter l'encombrement, les concepteurs de chalumeaux cherchent à réduire la section intérieure de la conduite.To avoid flashbacks inside the pipe and limit congestion, torch designers seek to reduce the interior section of the pipe.

Or, les chalumeaux actuels présentent l'inconvénient d'engendrer un niveau de bruit élevé provoqué par la flamme. Ces nuisances sonores obligent les utilisateurs de chalumeaux à porter des protections acoustiques.However, current torches have the disadvantage of generating a high level of noise caused by the flame. These noise nuisances force torch users to wear protective gear acoustic.

L'invention a pour but de proposer un brûleur, en particulier un chalumeau, dont les émissions sonores causées par la flamme sont réduites. The invention aims to provide a burner, in particular a torch, whose noise emissions caused by the flame are reduced.

A cet effet, l'invention a pour objet un brûleur, tel un chalumeau, de préférence monodard, à prémélange de débit supérieur à 1000 l/h du type précité, caractérisé en ce que la conduite d'alimentation est adaptée pour que, en tout point d'au moins une section transversale de celle-ci, le nombre de Reynolds du mélange circulant dans la conduite d'alimentation est inférieur à 3000, lorsque le brûleur ou chalumeau fonctionne en régime permanent à un débit supérieur à 1000 l/h.To this end, the subject of the invention is a burner, such as a torch, of preferably monodard, with premix of flow rate greater than 1000 l / h of the type above, characterized in that the supply line is adapted for that at any point of at least one cross section thereof, the Reynolds number of the mixture flowing in the supply line is less than 3000, when the burner or torch operates in steady state at a flow rate greater than 1000 l / h.

Suivant des modes particuliers de réalisation, le brûleur, en particulier le chalumeau, peut comporter l'une ou plusieurs des caractéristiques suivantes :

  • la vitesse du mélange dans ladite section transversale est inférieure à 5 m/s;
  • sur au moins un tronçon, la conduite d'alimentation comporte des parois longitudinales s'étendant suivant la direction de l'écoulement et subdivisant la section transversale de la conduite d'alimentation en canaux adjacents et, en tout point d'au moins une section transversale dudit tronçon subdivisé, le nombre de Reynolds du mélange circulant dans la conduite d'alimentation est inférieur à 3000, lorsque le brûleur ou le chalumeau fonctionne en régime établi ;
  • la conduite d'alimentation comporte, à l'extrémité d'alimentation une chambre de mélange dégagée, dans laquelle débouche un passage d'alimentation en mélange gazeux, la section de la chambre de mélange étant supérieure à la section du passage d'alimentation, la section de la conduite d'alimentation augmentant brutalement suivant le sens de l'écoulement, depuis le passage d'alimentation vers la chambre de mélange, notamment suivant un épaulement ;
  • la conduite d'alimentation comporte, sur un tronçon, un ensemble d'éléments formant une chicane, prolongé suivant le sens de l'écoulement par un tronçon dégagé ;
  • la conduite d'alimentation comporte, sur au moins un tronçon, un organe de guidage axial de l'écoulement ;
  • en aval du ou de chaque organe de guidage axial de l'écoulement, est disposé un tronçon dégagé de tranquillisation de l'écoulement.
  • le ou chaque organe de guidage axial comporte des parois longitudinales s'étendant suivant la direction de l'écoulement, lesquelles parois subdivisent la section transversale de la conduite d'alimentation en canaux adjacents définissant un motif régulier ;
  • les surfaces des sections transversales des canaux d'un même organe de guidage axial sont sensiblement égales ;
  • la longueur mesurée suivant la direction de l'écoulement, des canaux du ou de chaque organe de guidage est comprise entre quatre à dix fois, notamment six à huit fois le diamètre d'un canal ;
  • au moins deux tronçons de la conduite d'alimentation comportent des organes de guidage axial et en ce que les surfaces des sections transversales des canaux diminuent d'un organe à l'autre suivant le sens de l'écoulement du mélange ; et
  • la buse est délimitée intérieurement depuis la conduite jusqu'à son extrémité de sortie par un convergent ayant une forme générale en S, lequel convergent se relie tangentiellement à la conduite d'alimentation.
According to particular embodiments, the burner, in particular the torch, can include one or more of the following characteristics:
  • the speed of the mixture in said cross section is less than 5 m / s;
  • on at least one section, the supply pipe has longitudinal walls extending in the direction of flow and dividing the cross section of the supply pipe into adjacent channels and, at any point, at least one section transverse of said subdivided section, the Reynolds number of the mixture circulating in the supply line is less than 3000, when the burner or the torch is operating in steady state;
  • the supply line comprises, at the supply end, a clear mixing chamber, into which a gas mixture supply passage opens, the section of the mixing chamber being greater than the section of the supply passage, the section of the supply line suddenly increasing in the direction of flow, from the supply passage to the mixing chamber, in particular along a shoulder;
  • the supply line comprises, on a section, a set of elements forming a baffle, extended in the direction of flow by a clear section;
  • the supply line comprises, on at least one section, an axial flow guiding member;
  • downstream of the or each axial flow guiding member, is arranged a cleared section for tranquilizing the flow.
  • the or each axial guide member has longitudinal walls extending in the direction of flow, which walls subdivide the cross section of the supply pipe into adjacent channels defining a regular pattern;
  • the surfaces of the cross sections of the channels of the same axial guide member are substantially equal;
  • the length measured along the direction of flow, of the channels of the or each guide member is between four to ten times, in particular six to eight times the diameter of a channel;
  • at least two sections of the supply line comprise axial guide members and in that the surfaces of the cross sections of the channels decrease from one member to another in the direction of flow of the mixture; and
  • the nozzle is delimited internally from the pipe to its outlet end by a convergent having a general S shape, which converging tangentially connects to the supply pipe.

De préférence, le brûleur selon l'invention est un chalumeau, tel un chalumeau monodard.Preferably, the burner according to the invention is a torch, such as a monodard torch.

En outre, l'invention concerne également l'utilisation d'un chalumeau selon l'invention dans un procédé d'oxycombustion, mettant en oeuvre un mélange contenant au moins un gaz combustible et au moins un gaz comburant, tel un mélange contenant de l'oxygène et du propane.Furthermore, the invention also relates to the use of a torch according to the invention in an oxy-combustion process, putting using a mixture containing at least one combustible gas and at minus an oxidizing gas, such as a mixture containing oxygen and propane.

Plus généralement, un chalumeau monodard selon l'invention peut être appliqué à toute opération de brassage, de chaude avant retrait ("straightening" en anglais), de préchauffage avant soudage, de chauffage pour formage ou de toute autre opération de traitement thermique d'un matériau de préférence un matériau en métal ou en alliage métallique.More generally, a monodard torch according to the invention can be applied to any brewing operation, from warm before removal ("straightening" in English), preheating before welding, heating for forming or any other processing operation thermal of a material preferably a metal or alloy material metallic.

En outre, le brûleur selon l'invention peut être appliquée au domaine de la combustion c'est-à-dire à tout procédé mettant en oeuvre une flamme d'oxycombustion, par exemples dans un four et/ou dans le domaine du travail du verre.In addition, the burner according to the invention can be applied to the combustion field, i.e. any process using an oxy-fuel flame, for example in an oven and / or in the glass working.

En ce qui concerne les combustibles pouvant être utilisés, on peut citer, outre le propane, déjà mentionné, le méthane, le butane, l'éthylène, le propylène ou leurs mélanges, ou tout autre gaz ou mélange gazeux ayant une vitesse de déflagration modérée.Regarding the fuels that can be used, it is possible to quote, in addition to the propane, already mentioned, methane, butane, ethylene, propylene or their mixtures, or any other gas or gas mixture having a moderate deflagration speed.

Par ailleurs, bien que l'oxygène soit le comburant préféré, on peut aussi, dans certains cas utiliser de l'air, préférentiellement comprimé, en tant que gaz comburant.Furthermore, although oxygen is the preferred oxidizer, it is possible to also, in some cases, use air, preferably compressed, as an oxidizing gas.

L'invention sera mieux comprise à la lecture de la description d'un brûleur et, plus précisément, d'un chalumeau conforme à l'invention qui va suivre, donné uniquement à titre d'exemple en se référant aux dessins sur lesquels :

  • La figure 1 est une vue en coupe longitudinale d'un chalumeau monodard selon l'invention ;
  • La figure 2 est un diagramme montrant les résultats de mesure du niveau sonore relevé pour différents débits du chalumeau de la figure 1 et d'un chalumeau de l'état de la technique ; et
  • La figure 3 est une coupe longitudinale d'un autre mode de réalisation d'un chalumeau selon l'invention.
The invention will be better understood on reading the description of a burner and, more specifically, of a torch in accordance with the invention which follows, given solely by way of example with reference to the drawings in which:
  • Figure 1 is a longitudinal sectional view of a monodard torch according to the invention;
  • FIG. 2 is a diagram showing the measurement results of the sound level recorded for different flow rates of the torch of FIG. 1 and of a torch of the state of the art; and
  • Figure 3 is a longitudinal section of another embodiment of a torch according to the invention.

Le chalumeau 10 représenté sur la figure 1 comporte un injecteur de prémélange 12, une lance 14 formant une conduite d'alimentation du mélange et une buse unique d'extrémité 16. The torch 10 shown in Figure 1 includes an injector premix 12, a lance 14 forming a supply line for the mixture and a single end nozzle 16.

L'injecteur 12 comporte un corps 18 traversé par un conduit d'alimentation en gaz combustible 20. Le corps 18 comporte, en outre, un conduit latéral 22 d'alimentation en gaz comburant.The injector 12 comprises a body 18 crossed by a conduit fuel gas supply 20. The body 18 further comprises a side duct 22 for supplying oxidant gas.

Les conduits 20 et 22 débouchent dans un trou taraudé 24, dans lequel est vissé un collecteur 26 traversé par un passage axial 28 pour l'alimentation du mélange gazeux dans la conduite 14.
Le passage 28 a un diamètre d'environ 3 mm et est relié aux conduits 20 et 22 par des liaisons 30. Le passage 28 débouche au centre d'une face transversale plane du collecteur, notée 28A, qui s'étend perpendiculairement à l'axe du passage 28.The conduits 20 and 22 open into a threaded hole 24, into which a manifold 26 is screwed through through an axial passage 28 for feeding the gaseous mixture into the conduit 14.
The passage 28 has a diameter of approximately 3 mm and is connected to the conduits 20 and 22 by connections 30. The passage 28 opens at the center of a flat transverse face of the collector, denoted 28A, which extends perpendicularly to the passage axis 28.

La conduite 14 est formée par un tuyau de section circulaire ayant un diamètre intérieur égal à 21 mm environ et une longueur égale à 276 mm environ.The pipe 14 is formed by a pipe of circular section having an internal diameter equal to approximately 21 mm and a length equal to 276 mm approx.

Une extrémité d'entrée 32 de la conduite 14 comporte un filetage extérieur. Elle est vissée dans le trou taraudé 24. Cette extrémité s'appuie sur la face plane 28A.An inlet end 32 of the pipe 14 has a thread outside. It is screwed into the threaded hole 24. This end rests on the flat face 28A.

La conduite 14 comporte, à l'extrémité d'alimentation 32, une chambre de mélange dégagée 34 dans laquelle débouche axialement le passage d'alimentation 28. La section de la chambre de mélange 34 est égale à la section intérieure de la conduite 14. Cette section est très supérieure à la section du passage 28. Ainsi, la section de la conduite d'alimentation augmente brutalement suivant le sens d'écoulement du mélange. Cette variation brutale de section est assurée ici par un épaulement délimité par la face 28A.Line 14 includes, at the supply end 32, a open mixing chamber 34 into which the feed passage 28. The section of the mixing chamber 34 is equal to the inner section of the pipe 14. This section is very greater than the section of the passage 28. Thus, the section of the pipe supply increases suddenly according to the direction of flow of the mixed. This brutal variation in section is ensured here by a shoulder delimited by the face 28A.

Depuis son extrémité d'entrée 32 jusqu'à la buse 16, la conduite 14 contient des organes successifs de régulation du flux gazeux espacés par des tronçons dégagés.From its inlet end 32 to the nozzle 16, the pipe 14 contains successive organs for regulating the gas flow spaced apart by clear sections.

En particulier, une chicane 36 est disposée en aval de l'extrémité d'entrée 32. Celle-ci délimite avec la face plane 28A de l'injecteur la chambre de mélange 34 qui s'étend sur 21 mm. In particular, a baffle 36 is arranged downstream of the end inlet 32. This defines with the flat face 28A of the injector the mixing chamber 34 which extends over 21 mm.

La chicane 36 est formée par un ensemble aggloméré d'éléments analogues, par exemple des billes indépendantes 36A retenues entre deux grilles transversales d'extrémité 36B. Les billes 36A ont un diamètre de 4 mm. Les grilles 36B sont constituées d'un treillis métallique tressé dont les brins voisins sont écartés d'environ 0,5 mm.Chicane 36 is formed by an agglomerated set of elements analogues, for example independent balls 36A retained between two transverse end grids 36B. 36A balls have a diameter 4 mm. 36B grids consist of a braided wire mesh whose neighboring strands are spaced about 0.5 mm apart.

Cette chicane peut également être formée par un matériau poreux, notamment un matériau fritté.This baffle can also be formed by a porous material, in particular a sintered material.

La chicane 36 s'étend sur une longueur de 30 mm. Elle est suivie par une chambre dégagée de tranquillisation 38 s'étendant également sur une longueur de 30 mm.The baffle 36 extends over a length of 30 mm. She is followed by an unobstructed tranquilization chamber 38 also extending over a length of 30 mm.

La chambre 38 est délimitée en aval par un organe 40 de guidage axial de l'écoulement. Cet organe est formé par un tronçon d'une longueur de 24 mm, d'une structure en nid d'abeille dont les parois s'étendent suivant l'axe de la conduite 14. Ainsi, l'organe 40 est formé d'un ensemble de parois longitudinales subdivisant la conduite 14 en un ensemble de canaux parallèles. Le diamètre de chaque canal est de 4 mm. Les canaux ont ici une section hexagonale. Toutefois, ils peuvent aussi être de section carrée ou circulaire.Chamber 38 is delimited downstream by a guide member 40 axial flow. This organ is formed by a section with a length 24 mm, of a honeycomb structure whose walls extend along the axis of the pipe 14. Thus, the member 40 is formed of an assembly of longitudinal walls dividing the pipe 14 into a set of parallel channels. The diameter of each channel is 4 mm. The channels here have a hexagonal section. However, they can also be square or circular section.

En aval de l'organe 40, est prévue une seconde chambre de tranquillisation 42 s'étendant sur une longueur de 85 mm. Elle est délimitée à son extrémité aval par un second organe de guidage axial 44 formé par une structure en nid d'abeille dont le diamètre de chaque canal est égal à 1 mm. Cet organe 44, dont les canaux s'étendent suivant la direction de l'écoulement, a une longueur de 6 mm.Downstream of the member 40, a second chamber is provided. still 42 extending over a length of 85 mm. She is delimited at its downstream end by a second axial guide member 44 formed by a honeycomb structure whose diameter of each channel is equal to 1 mm. This organ 44, the channels of which extend along the direction of flow, has a length of 6 mm.

En aval de l'organe 44 est disposée une grille 46 dont la maille est d'environ 0,5 mm. Cette grille délimite avec l'organe 44 une chambre dégagée de tranquillisation 48 s'étendant sur 50 mm.Downstream of the member 44 is disposed a grid 46, the mesh of which is about 0.5 mm. This grid delimits with the organ 44 a room released from stilling 48 extending over 50 mm.

La grille 46 est séparée de l'extrémité de sortie de la conduite 14 par une chambre dégagée 50 s'étendant sur 30 mm. The grid 46 is separated from the outlet end of the pipe 14 by an open chamber 50 extending over 30 mm.

La buse 16 a un profil intérieur de révolution. Elle est délimitée depuis la conduite 14 jusqu'à son extrémité de sortie 52 par un convergent 54 ayant un profil général en S. Le convergent 54 se raccorde tangentiellement à l'extrémité de sortie de la conduite 14. L'extrémité de sortie 52 de la buse a un diamètre de 3 mm, de sorte que le débit nominal de mélange d'une telle buse est de 2000 l/h.The nozzle 16 has an inner profile of revolution. It is delimited from line 14 to its outlet end 52 via a converge 54 having a general profile in S. Convergent 54 is tangentially connects to the outlet end of the pipe 14. The outlet end 52 of the nozzle has a diameter of 3 mm, so that the nominal mixing flow rate of such a nozzle is 2000 l / h.

Le profil du convergent 54 est par exemple défini par un polynôme d'ordre 5 calculé selon la méthode de Bell et Metha, décrite dans la publication "Bell, J.H. and Metha, R.D. Contraction Design for Small Low Speed Wind Tunnels, AIAA Journal, 27, 372-4, (1989)". Cette buse a un grand rapport de contraction. Le rapport de contraction qui est défini par la section d'entrée de la buse sur sa section de sortie est d'environ 50. De plus, le rapport d'aspect, à savoir la longueur de la buse sur son diamètre d'entrée est d'environ 2,6. Avantageusement, la surface du convergent 54 est choisie aussi lisse que possible.The profile of the convergent 54 is for example defined by a polynomial of order 5 calculated according to the Bell and Metha method, described in publication "Bell, J.H. and Metha, R.D. Contraction Design for Small Low Speed Wind Tunnels, AIAA Journal, 27, 372-4, (1989) ". This nozzle has a great contraction ratio. The contraction ratio which is defined by the inlet section of the nozzle on its outlet section is approximately 50. From plus, the aspect ratio, i.e. the length of the nozzle over its diameter input is about 2.6. Advantageously, the surface of the convergent 54 is chosen to be as smooth as possible.

La buse 16 est reliée à l'extrémité de la conduite 14 par un manchon taraudé de liaison 56.The nozzle 16 is connected to the end of the pipe 14 by a threaded connection sleeve 56.

Dans le chalumeau décrit ici, les dispositifs de positionnement et de fixation des organes 36, 40, 44 et 46, constitués par exemple par des tronçons tubulaires formant entretoises entre les organes, sont adaptés pour assurer la continuité de la paroi intérieure de la lance, de sorte que celle-ci est intérieurement dépourvue d'aspérité, de rainure et de variation brusque de section.In the torch described here, the positioning devices and for fixing members 36, 40, 44 and 46, constituted for example by tubular sections forming spacers between the members, are adapted to ensure the continuity of the inner wall of the lance, so that it is internally devoid of roughness, groove and variation abrupt section.

La conduite 14 du chalumeau décrit ici présente une section intérieure de grande surface par rapport à celle de la section de sortie de la buse.The pipe 14 of the torch described here has a section interior of large area compared to that of the outlet section of the nozzle.

En particulier, pour les débits normaux d'utilisation de ce chalumeau compris entre 1000 l/h et 3000 l/h, le nombre de Reynolds du mélange circulant dans la conduite 14 est en tout point d'au moins une section transversale de la conduite inférieure à 3000, lorsque le chalumeau fonctionne en régime permanent.In particular, for normal flow rates of use of this torch between 1000 l / h and 3000 l / h, the Reynolds number of mixture flowing in line 14 is at least one pipe cross-section less than 3000, when the torch operates in steady state.

Pour une vitesse de sortie des gaz de la buse égale à environ 100 m/s, soit un débit d'environ 2500 l/h, la vitesse dans la conduite est sensiblement égale à 2 m/s, ce qui donne un nombre de Reynolds sensiblement égal à 2000 dans les tronçons dégagés 38, 42, 48, 50 du tube.For a nozzle gas exit speed of approximately 100 m / s, i.e. a flow rate of approximately 2500 l / h, the speed in the pipe is substantially equal to 2 m / s, which gives a Reynolds number substantially equal to 2000 in the cleared sections 38, 42, 48, 50 of the tube.

Dans ces conditions, l'écoulement du mélange gazeux dans la conduite d'alimentation est un écoulement sensiblement laminaire.Under these conditions, the flow of the gas mixture in the supply line is a substantially laminar flow.

Il a été constaté que la laminarisation de l'écoulement dans la conduite 14 conduit à une diminution de l'ordre de 20 décibels (dBA) du niveau de bruit mesuré au niveau de la buse du chalumeau. Une telle amélioration est constatée notamment pour un tel diamètre de la conduite pour des vitesses du mélange dans la conduite inférieures à 5 m/s.It has been found that the laminarization of the flow in the line 14 leads to a decrease of around 20 decibels (dBA) in noise level measured at the nozzle of the torch. Such a improvement is noted in particular for such a diameter of the pipe for speeds of the mixture in the pipe lower than 5 m / s.

La figure 2 présente des résultats expérimentaux de mesures du niveau de bruit. Les niveaux de bruit ont été relevés à 0,5 m de la buse dans le plan de sortie de celle-ci. Les niveaux de référence ont été obtenus avec un chalumeau de type "Varial G2", commercialisé en France par la Soudure Autogène Française. Ce chalumeau était équipé d'une buse d'un débit nominal de mélange de 2000 l/h ayant un diamètre de sortie de 3 mm. La richesse du mélange utilisé, du propane et de l'oxygène, était de 1,33. Le diamètre intérieur de la conduite d'alimentation cylindrique d'un tel chalumeau est de 8 mm.Figure 2 presents experimental results of measurements of the noise level. Noise levels were raised 0.5 m from the nozzle in the exit plan from it. The reference levels have been obtained with a "Varial G2" type torch, sold in France by French Autogenic Welding. This torch was equipped a nozzle with a nominal mixing flow of 2000 l / h having a diameter 3 mm outlet. The richness of the mixture used, propane and oxygen, was 1.33. The inner diameter of the pipe cylindrical feed of such a torch is 8 mm.

La courbe montre les niveaux sonores relevés pour ce chalumeau de référence et le chalumeau 10 de la figure 1, pour différents débits allant de 1200 l/h à 3000 l/h du même mélange. Ces niveaux sonores sont figurés respectivement par des ronds noirs et des carrés blancs.The curve shows the sound levels recorded for this torch reference and the torch 10 of FIG. 1, for different flow rates ranging from 1200 l / h to 3000 l / h of the same mixture. These sound levels are represented respectively by black circles and white squares.

On constate également une très nette diminution du niveau sonore. Cette diminution varie de plus de 30 décibels (dBA) pour un débit de 1200 l/h à environ 15 décibels (dBA) pour un débit de 3000 l/h. There is also a very marked reduction in noise level. This reduction varies by more than 30 decibels (dBA) for a throughput of 1200 l / h at around 15 decibels (dBA) for a flow rate of 3000 l / h.

Une hypothèse d'explication de la diminution du niveau de bruit mesurée est la suivante.A hypothesis of explanation of the reduction in the noise level measured is as follows.

Le bruit émis par une flamme provient d'une part du dard (partie centrale de la flamme) et d'autre part du panache (partie périphérique de la flamme).The noise emitted by a flame comes on the one hand from the sting (part central flame) and on the other hand the plume (peripheral part of the flame).

Il est communément admis que le bruit engendré par une flamme provient des fluctuations de la flamme.It is commonly accepted that the noise generated by a flame comes from the fluctuations of the flame.

Toutefois, selon l'hypothèse avancée ici, l'essentiel du bruit de la flamme proviendrait du dard et notamment de l'instabilité de la surface de celui-ci.However, according to the hypothesis advanced here, most of the noise from the flame would come from the sting and in particular from the instability of the surface of this one.

L'analyse de la turbulence de l'écoulement en sortie de la buse d'un chalumeau de l'état de la technique paraít trop faible pour expliquer à elle seule les fluctuations de la surface du dard. Cependant, il est supposé que les faibles turbulences rencontrées à la base du dard sont convectées par la flamme à la vitesse de l'écoulement tout en étant amplifiées par l'instabilité de Darrieus-Landau (Landau, L. Acta Physicochimica URSS, vol 19, p. 77, (1944)), et que lorsque l'amplitude des perturbations est devenue suffisamment grande, la flamme devient auto-turbulente. Aussi, la turbulence, même faible, de l'écoulement semble suffire pour exciter l'instabilité de Darrieus-Landau.Analysis of the turbulence of the flow leaving the nozzle of a prior art torch seems too weak to explain the fluctuations of the sting surface alone. However, it is assumed that the weak turbulence encountered at the base of the stinger is convected by the flame at the speed of flow while being amplified by the instability of Darrieus-Landau (Landau, L. Acta Physicochimica USSR, vol 19, p. 77, (1944)), and that when the amplitude disturbance has become large enough, the flame becomes self-turbulent. Also, the turbulence, even weak, of the flow seems to be enough to excite the instability of Darrieus-Landau.

Le chalumeau selon l'invention a été conçu afin de réduire encore les turbulences présentes à la base du dard.The torch according to the invention was designed in order to further reduce the turbulence present at the base of the sting.

A cet effet, le chalumeau a été dimensionné afin d'obtenir un écoulement sensiblement laminaire à l'intérieur de la lance.To this end, the torch has been sized to obtain a substantially laminar flow inside the lance.

Dans le chalumeau représenté sur la figure 1, les phénomènes suivants sont observés.In the torch shown in Figure 1, the phenomena following are observed.

Les gaz combustible et comburant sont mis en contact dans le passage d'alimentation 28. La brusque variation du diamètre à l'extrémité d'entrée 32 provoque une recirculation des gaz à l'intérieur de la chambre de mélange 34. En particulier, des tourbillons prennent naissance à la sortie du passage 28, ce qui engendre un écoulement turbulent dans la chambre 34. Cet écoulement turbulent favorise le mélange homogène des gaz.The combustible and oxidizing gases are brought into contact in the feed passage 28. The sudden change in diameter at the end inlet 32 causes gas recirculation inside the chamber 34. In particular, eddies arise at the exit from passage 28, which creates a turbulent flow in the chamber 34. This turbulent flow promotes the homogeneous mixing of gas.

Afin de créer un phénomène de recirculation donnant naissance à des tourbillons dans la chambre de mélange, il convient que la variation de la section depuis la section du passage 28 jusqu'à la section maximum de la chambre de mélange s'effectue sur une faible longueur suivant l'axe de la conduite 14. En particulier, le profil doit être compris à l'extérieur d'un cône dont l'angle au sommet est égal à 14° et de préférence supérieur ou égal à 20°.In order to create a recirculation phenomenon giving rise to vortices in the mixing chamber, the variation should from section from section of passage 28 to maximum section of the mixing chamber takes place over a short length along the axis of the pipe 14. In particular, the profile must be understood on the outside a cone whose angle at the top is equal to 14 ° and preferably greater than or equal to 20 °.

La longueur de la chambre de mélange est avantageusement égale au diamètre de celle-ci.The length of the mixing chamber is advantageously equal the diameter of the latter.

Le flux des gaz combustible et comburant mélangés dans la chambre 34 circule ensuite de manière aléatoire au travers de la chicane 36. L'échelle spatiale des turbulences est ainsi réduite à une dimension de l'ordre du diamètre des billes 36A (4 mm).The flow of combustible and oxidizing gases mixed in the room 34 then flows randomly through the chicane 36. The spatial scale of turbulence is thus reduced to one dimension on the order of the diameter of the balls 36A (4 mm).

La chambre de tranquillisation 38 assure ensuite une dissipation visqueuse des tourbillons encore présents dans l'écoulement. La longueur L de la chambre 38, nécessaire pour un premier amortissement des tourbillons de l'ordre d'un facteur trois, est donnée par L = U.m2/(4π2.ν) dans laquelle U est la vitesse moyenne du mélange, m est la taille de la maille et v la viscosité du mélange.The stilling chamber 38 then ensures a viscous dissipation of the vortices still present in the flow. The length L of the chamber 38, necessary for a first damping of the vortices of the order of a factor of three, is given by L = Um 2 / (4π 2 .ν) in which U is the average speed of the mixture, m is the size of the mesh and v the viscosity of the mixture.

L'organe de guidage axial 40 assure ensuite une atténuation des fluctuations des vitesses transversales dans l'écoulement. En particulier, il dirige l'écoulement suivant la direction de l'axe de la conduite 14.The axial guide member 40 then ensures attenuation of the fluctuations in transverse velocities in the flow. In particular, it directs the flow in the direction of the axis of the pipe 14.

Avantageusement, la longueur de l'organe à structure en nid d'abeille est de quatre à dix fois et de préférence de six à huit fois le diamètre des canaux constituant ledit organe.Advantageously, the length of the member with a nest structure bee is four to ten times and preferably six to eight times the diameter of the channels constituting said organ.

La chambre de tranquillisation 42, disposée en aval de l'organe 40, doit avoir une longueur suffisante pour amortir les turbulences engendrées par l'organe 40. Comme précédemment, cette longueur L'optimale est donnée par la relation L' = U.m2/(4π2.ν) dans laquelle U est la vitesse du mélange, m le diamètre des canaux de la structure, et v la viscosité du mélange. Dans l'exemple décrit, cette longueur est égale à 85 mm et correspond à un amortissement des turbulences de l'ordre d'un facteur 10.The stilling chamber 42, arranged downstream of the member 40, must have a length sufficient to absorb the turbulence generated by the member 40. As before, this length The optimum is given by the relation L '= Um 2 / (4π 2 .ν) in which U is the speed of the mixture, m the diameter of the channels of the structure, and v the viscosity of the mixture. In the example described, this length is equal to 85 mm and corresponds to a damping of turbulence on the order of a factor of 10.

De manière analogue, l'organe 44, dont le diamètre des canaux est inférieur à celui des canaux de l'organe 40, assure avec la chambre de tranquillisation aval 48 une nouvelle atténuation des vitesses transversales dans l'écoulement et améliore la directivité de l'écoulement.Similarly, the member 44, the diameter of the channels of which is lower than that of the channels of the member 40, ensures with the downstream stabilization 48 a new reduction in speeds transverse in the flow and improves the directivity of the flow.

La grille 46 associée à la chambre 50 effectue un amortissement final des turbulences de l'écoulement.The grid 46 associated with the chamber 50 performs a damping final turbulence of the flow.

Lorsque le chalumeau fonctionne en régime établi, c'est-à-dire avec un débit constant compris entre 1000 et 3000 l/h, le nombre de Reynolds de l'écoulement dans les chambres dégagées est inférieur à 3000. Ainsi, un écoulement laminaire est obtenu à l'intérieur de ces chambres. La laminarisation de l'écoulement dans la conduite 14 réduit considérablement le bruit produit par la flamme.When the torch operates in steady state, that is to say with a constant flow rate between 1000 and 3000 l / h, the number of Reynolds of flow in open chambers is less than 3000. Thus, a laminar flow is obtained inside these bedrooms. The laminarization of the flow in line 14 reduces considerably the noise produced by the flame.

En outre, la présence de la chicane 36 et des organes de guidage axial de l'écoulement 40, 44 améliore encore la réduction du niveau de bruit.In addition, the presence of the baffle 36 and the guide members axial flow 40, 44 further improves the reduction in the level of noise.

Sur la figure 3 est représentée une variante de réalisation du chalumeau 10 de la figure 1. Ce chalumeau ne se distingue de celui de la figure 1 que par sa conduite d'alimentation. Celle-ci est formée par un tube 100 de section circulaire de diamètre intérieur égal à 10 mm et de longueur égale à 221 mm. Ce tube comporte intérieurement deux organes identiques 102, 104 de guidage axial du mélange. Ces organes sont formés par des structures en nid d'abeille dont les parois s'étendent longitudinalement. Ces parois délimitent des canaux de diamètre égal à 1 mm. In Figure 3 is shown an alternative embodiment of the torch 10 in Figure 1. This torch is indistinguishable from that of the Figure 1 only by its supply line. This is formed by a tube 100 of circular section with internal diameter equal to 10 mm and of length equal to 221 mm. This tube has two internal parts identical 102, 104 for axial guidance of the mixture. These organs are formed by honeycomb structures whose walls extend longitudinally. These walls delimit channels of diameter equal to 1 mm.

Ces deux tronçons 102, 104 s'étendent chacun sur une longueur de 60 mm. Ils délimitent entre eux une chambre de tranquillisation dégagée portant la référence 106. Celle-ci s'étend sur une longueur de 30 mm.These two sections 102, 104 each extend over a length 60 mm. They define between them a tranquilization chamber open bearing the reference 106. This extends over a length of 30 mm.

Entre le second tronçon 104 et la buse 16 est prévue une chambre de tranquillisation 108 s'étendant sur une longueur de 50 mm.Between the second section 104 and the nozzle 16 is provided a chamber still 108 extending over a length of 50 mm.

Dans le chalumeau décrit sur la figure 3, un débit de l'ordre d'environ 2800 l/h conduit à une vitesse dans la conduite d'alimentation égale à 10 m/s. Le nombre de Reynolds du mélange s'écoulant dans les canaux parallèles délimités par les structures en nid d'abeille est sensiblement égal à 500. Ainsi, dans les tronçons de la conduite occupés par les organes à structure en nid d'abeille, le nombre de Reynolds de l'écoulement est inférieur à 3000 sur toute la section de la conduite. Ceci provoque une laminarisation de l'écoulement d'où il résulte une stabilisation améliorée du dard de la flamme.In the torch described in Figure 3, a flow of the order about 2800 l / h leads to a speed in the supply line equal to 10 m / s. The Reynolds number of the mixture flowing in the parallel channels bounded by the honeycomb structures is substantially equal to 500. Thus, in the sections of the pipe occupied by honeycomb structures, the Reynolds number of the flow is less than 3000 over the entire section of the pipe. This causes laminarization of the flow from which it results improved stabilization of the flame dart.

Le chalumeau décrit sur la figure 3 engendre un niveau de bruit nettement inférieur au chalumeau de référence.The torch described in Figure 3 generates a noise level significantly lower than the reference torch.

Les chalumeaux décrits ici comportent une lance rectiligne. Toutefois, celle-ci peut comporter un tronçon coudé (notamment à son extrémité de sortie), sans que le niveau de bruit mesuré ne soit significativement augmenté.The torches described here have a straight lance. However, this may include a bent section (in particular at its output end), without the measured noise level being significantly increased.

Claims (14)

  1. Burner with premixing, having a flow rate greater than 1000 l/h, of the type comprising a gas mixture feed pipe (14) having one end (32) for feeding the gas mixture and a single nozzle (16) for establishing the flame, fitted at the other end of the said feed pipe (14), characterized in that the feed pipe (14) is designed so that, at every point of at least one cross section of the latter, the Reynolds number of the mixture flowing in the feed pipe (14) is less than 3000 when the burner operates in the steady state with a flow rate greater than 1000 l/h.
  2. Burner according to Claim 1, characterized in that the velocity of the mixture in the said cross section is less than 5 m/s.
  3. Burner according to Claim 1 or 2, characterized in that, over at least one portion (102, 104), the feed pipe (14) has longitudinal walls extending in the direction of the flow and subdividing the cross section of the feed pipe (14) into adjacent channels and in that, at every point of at least one cross section of the said subdivided portion, the Reynolds number of the mixture flowing in the feed pipe (14) is less than 3000 when the burner operates in the steady state.
  4. Burner according to one of the preceding claims, characterized in that the feed pipe (14) includes, at the feed end (32), an open mixing chamber (34) into which a gas mixture feed passage (28) opens, the cross section of the mixing chamber (34) being greater than the cross section of the feed passage (28) and the cross section of the feed pipe (14) increasing suddenly in the direction of flow, from the feed passage (28) to the mixing chamber (34), especially in a shoulder (28A).
  5. Burner according to one of the preceding claims, characterized in that the feed pipe (14) includes, over one portion, an array of elements (36A) forming a baffle (36) and being extended in the direction of flow by an open portion (38).
  6. Burner according to one of the preceding claims, characterized in that the feed pipe (14) includes, over at least one portion, a member (40, 44; 102, 104) for axially guiding the flow.
  7. Burner according to Claim 6, characterized in that an open portion (42, 48; 106, 108) for steadying the flow is located downstream of the or each member (40, 44; 102, 104) for axially guiding the flow.
  8. Burner according to Claim 6 or 7, characterized in that the or each axial guiding member (40, 44; 102, 104) comprises longitudinal walls extending in the direction of flow, which walls subdivide the cross section of the feed pipe (14) into adjacent channels defining a regular pattern.
  9. Burner according to Claim 8, characterized in that the surface areas of the cross sections of the channels of the same axial guiding member (40, 44; 102, 104) are approximately equal.
  10. Burner according to Claim 9, characterized in that the length of the channels of the or each guiding member (40, 44), measured in the direction of flow, is between four and ten times, especially six to eight times, the diameter of a channel.
  11. Burner according to Claim 9 or 10, characterized in that at least two portions of the feed pipe (14) include axial guiding members (40, 44) and in that the surface areas of the cross sections of the channels decrease from one member to another in the direction of flow of the mixture.
  12. Burner according to one of the preceding claims, characterized in that the nozzle (16) is internally defined from the pipe (14) to its exit end (52) by a convergent part (54) having the overall shape of an S, which convergent part (54) joins the feed pipe (14) tangentially.
  13. Burner according to one of Claims 1 to 12, characterized in that it is a torch, preferably a monocone torch.
  14. Use of a torch, preferably a monocone torch, according to Claim 13 in an oxycombustion process employing a gas mixture containing at least one combustible gas and at least one oxidizer gas.
EP98914950A 1997-03-28 1998-03-19 Premix burner with a flow rate of more than 1000 litres/hour Expired - Lifetime EP0970325B1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
FR9703879 1997-03-28
FR9703879A FR2761457B1 (en) 1997-03-28 1997-03-28 MONODARD TORCH WITH A PREMIX OF FLOW MORE THAN 1000 LITERS / HOUR
PCT/FR1998/000553 WO1998044296A1 (en) 1997-03-28 1998-03-19 Single inner cone blowpipe, with flow rate premix more than 1000 litres/hour

Publications (2)

Publication Number Publication Date
EP0970325A1 EP0970325A1 (en) 2000-01-12
EP0970325B1 true EP0970325B1 (en) 2001-10-31

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EP98914950A Expired - Lifetime EP0970325B1 (en) 1997-03-28 1998-03-19 Premix burner with a flow rate of more than 1000 litres/hour

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EP (1) EP0970325B1 (en)
AU (1) AU6925498A (en)
DE (1) DE69802273T2 (en)
ES (1) ES2167071T3 (en)
FR (1) FR2761457B1 (en)
WO (1) WO1998044296A1 (en)

Cited By (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101430091B (en) * 2007-11-05 2010-07-21 中南大学 Catalytic combustion premixing device

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
DE10024410A1 (en) * 2000-05-19 2001-11-22 Kromschroeder Ag G Arrangement for regulating a combustion device

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FR322011A (en) * 1902-06-11 1903-01-24 Cie Universelle D Acetylene Oxy-acetylene torch
DE1913014C3 (en) * 1969-03-14 1974-02-28 Aga Ab, Lidingoe (Schweden) Burners for fuel gas and oxygen or air as an oxidizer
DE2009357A1 (en) * 1970-02-27 1971-09-09 Kreis, Philipp, 8000 München Gas burner
FR2264247A1 (en) * 1974-03-14 1975-10-10 Pleven Gicquel Sarl Granits Cutting torch for granite - has venturi outlet at combustion chamber outlet
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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
CN101430091B (en) * 2007-11-05 2010-07-21 中南大学 Catalytic combustion premixing device

Also Published As

Publication number Publication date
WO1998044296A1 (en) 1998-10-08
FR2761457A1 (en) 1998-10-02
DE69802273T2 (en) 2002-07-11
FR2761457B1 (en) 1999-05-14
DE69802273D1 (en) 2001-12-06
EP0970325A1 (en) 2000-01-12
ES2167071T3 (en) 2002-05-01
AU6925498A (en) 1998-10-22

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