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EP3760924B1 - Smoke-producing device with silencer in a smoke evacuation conduit - Google Patents

Smoke-producing device with silencer in a smoke evacuation conduit Download PDF

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Publication number
EP3760924B1
EP3760924B1 EP20183656.6A EP20183656A EP3760924B1 EP 3760924 B1 EP3760924 B1 EP 3760924B1 EP 20183656 A EP20183656 A EP 20183656A EP 3760924 B1 EP3760924 B1 EP 3760924B1
Authority
EP
European Patent Office
Prior art keywords
upstream
downstream
smoke
central tube
section
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.)
Active
Application number
EP20183656.6A
Other languages
German (de)
French (fr)
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EP3760924A1 (en
Inventor
Benjamin Laurent
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.)
Poujoulat SA
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Poujoulat SA
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Publication date
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Publication of EP3760924A1 publication Critical patent/EP3760924A1/en
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Publication of EP3760924B1 publication Critical patent/EP3760924B1/en
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Classifications

    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J13/00—Fittings for chimneys or flues 
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N1/00—Silencing apparatus characterised by method of silencing
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N1/00—Silencing apparatus characterised by method of silencing
    • F01N1/02—Silencing apparatus characterised by method of silencing by using resonance
    • F01N1/04—Silencing apparatus characterised by method of silencing by using resonance having sound-absorbing materials in resonance chambers
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23M—CASINGS, LININGS, WALLS OR DOORS SPECIALLY ADAPTED FOR COMBUSTION CHAMBERS, e.g. FIREBRIDGES; DEVICES FOR DEFLECTING AIR, FLAMES OR COMBUSTION PRODUCTS IN COMBUSTION CHAMBERS; SAFETY ARRANGEMENTS SPECIALLY ADAPTED FOR COMBUSTION APPARATUS; DETAILS OF COMBUSTION CHAMBERS, NOT OTHERWISE PROVIDED FOR
    • F23M20/00—Details of combustion chambers, not otherwise provided for, e.g. means for storing heat from flames
    • F23M20/005—Noise absorbing means
    • G—PHYSICS
    • G10—MUSICAL INSTRUMENTS; ACOUSTICS
    • G10K—SOUND-PRODUCING DEVICES; METHODS OR DEVICES FOR PROTECTING AGAINST, OR FOR DAMPING, NOISE OR OTHER ACOUSTIC WAVES IN GENERAL; ACOUSTICS NOT OTHERWISE PROVIDED FOR
    • G10K11/00—Methods or devices for transmitting, conducting or directing sound in general; Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/16—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general
    • G10K11/161—Methods or devices for protecting against, or for damping, noise or other acoustic waves in general in systems with fluid flow
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01N—GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR MACHINES OR ENGINES IN GENERAL; GAS-FLOW SILENCERS OR EXHAUST APPARATUS FOR INTERNAL COMBUSTION ENGINES
    • F01N2470/00—Structure or shape of gas passages, pipes or tubes
    • F01N2470/02—Tubes being perforated
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F23—COMBUSTION APPARATUS; COMBUSTION PROCESSES
    • F23J—REMOVAL OR TREATMENT OF COMBUSTION PRODUCTS OR COMBUSTION RESIDUES; FLUES 
    • F23J2900/00—Special arrangements for conducting or purifying combustion fumes; Treatment of fumes or ashes
    • F23J2900/13003—Means for reducing the noise in smoke conducing ducts or systems

Definitions

  • the present invention relates to the technical field of noise attenuators (also called “silencers”) for the smoke evacuation ducts fitted to a smoke-producing device, such as a generator motor, a boiler, or the like.
  • a smoke-producing device such as a generator motor, a boiler, or the like.
  • certain appliances that produce fumes such as generator motors, boilers or others, can generate noise, in particular due to the motorization, the burner and/or or of the fan which equips them, this noise being propagated in the associated ducts or casings, in particular in the smoke evacuation ducts.
  • the sound level of this noise is sometimes significant; it is specific to each installation and is characterized by an amplitude and a frequency range (between a few tens and a few thousand Hertz).
  • noise attenuating devices also called silencers, placed on the smoke evacuation duct, between an upstream section and a downstream section of the latter.
  • noise attenuators or silencers which operate according to a so-called “reactive” principle, consisting in causing sound waves to penetrate into a cavity, in a suitable way to change its frequency.
  • Silencers of the so-called “absorptive” type are also known in which an absorptive material (in particular high-density mineral fibers) is used to seek to absorb the sound waves.
  • absorptive material in particular high-density mineral fibers
  • Such devices generally have a good efficiency for the absorption of waves in the high frequencies (up to 40dB of absorption between 1000 and 3000 Hertz), this efficiency being nevertheless reduced in the field of the low frequencies (of the order of a few dB up to 400 - 500 Hertz).
  • the document EP 2 857 748 describes for its part a noise attenuator device using both the “reactive” principle and the “absorptive” principle, so as to seek to benefit from their respective advantages.
  • the corresponding noise attenuator device comprises a central tube which is provided, taking into account the direction of movement of the smoke, with an upstream extension suitable for its connection to an upstream flue section, and with a downstream extension suitable for its connection to a section of downstream flue.
  • This central tube has perforations over part of its length and it is surrounded by an outer tube to define between them a sound absorption chamber, which outer tube is connected to said central tube, always taking into account the direction of movement of the fumes , by an upstream end wall and by a downstream end wall, which delimit the length of said acoustic absorption chamber.
  • This acoustic absorption chamber is partially filled, here in its upstream part, by an acoustic absorbent material which fills its thickness between the central tube and the outer tube.
  • the perforations of the central tube are provided on an upstream section formed facing the acoustic absorptive material and also facing a part of the acoustic absorption chamber devoid of said acoustic absorptive material.
  • a noise attenuator device is thus obtained, the absorptive part of which is located upstream, followed by the reactive part located downstream.
  • the present invention proposes a smoke-producing apparatus (such as a generator set engine, a boiler or the like), defined in claim 1.
  • the upstream part of the noise attenuator device comprises a cavity having the effect, in particular, of modifying the frequency of the waves, and the downstream part has an action of absorbing the waves, thanks to the acoustic absorptive material, in order to attenuate the sound level.
  • the absorptive part is thus located at the output of the noise attenuator device, downstream of the reactive part, and it attenuates the regenerated noise and consequently increases the performance of the silencer.
  • the cavity upstream of the sound absorption chamber is delimited, on one side, by the edge of the sound absorbing material, which also performs at this level a sound wave absorption function, contributing to improving the efficiency of the device.
  • the figures 1 to 4 illustrate a first embodiment of a noise attenuator device 1 according to the invention, intended to be integrated into the smoke evacuation duct 2 fitted to a smoke-producing device 3, for example an engine or a boiler.
  • This noise attenuator device 1 is in particular here arranged to be integrated between an upstream section 2a and a downstream section 2b of the flue 2 ( figure 4 ) to form part of this duct 2 and also to fulfill its function of reducing the noise coming from the device 3.
  • the device 3 is simply shown schematically in dotted lines at the upstream end of the upstream pipe section 2a.
  • the orientation arrow 4 illustrates the upstream/downstream direction of movement of the fumes and the sound waves in the duct 2 (and therefore also in the noise attenuator device 1).
  • This upstream/downstream direction is used in the remainder of the description to define certain structural parts of the noise attenuator device 1.
  • the upstream 12 and downstream 13 end walls extend parallel to each other. They each have a planar annular shape centered on the longitudinal axis A, and they define between them the length L of the sound absorption chamber 11.
  • Cylindrical rings, 15 and 16 respectively, extend the circular peripheral edge of the upstream 12 and downstream 13 end walls, secured to the latter by welding. These cylindrical crowns 15 and 16 extend inwards, that is to say they are oriented opposite one another.
  • the upstream 7 and downstream 9 extensions consist of cylindrical structures comprising an insulated wall, formed by two concentric tubes which sandwich an insulating material.
  • the upstream extension 7 of the central tube 5 is in the form of a male end piece which is adapted to cooperate with a female end piece of the upstream flue section 2a, and its downstream extension 9 is in the form of a female end piece adapted to cooperate with a male end of the downstream flue section 2b.
  • upstream 7 and downstream 9 extensions extend mainly outwards from the end walls 12 and 13, their inner tube 7a, 9a being joined by welding with the edge of the central orifice of said end walls 12 , 13, and their outer tube 7b, 9b being secured by welding against the outer face of said end walls 12, 13.
  • An inner section 7a1, 9a1 of the inner tubes 7a, 9a of the upstream 7 and downstream 9 extensions extends towards the inside of the sound absorption chamber 11. These two inner sections 7a1, 9a1 extend opposite one on the other, and they receive by simple fitting the upstream 6 and downstream 8 ends of the central tube 5.
  • the outer tube 10 consists of a cylindrical shell obtained from a curved plate, the two facing longitudinal edges of which, following the bending, are assembled together by welding, and the upstream and downstream ends of which are secured by removable interlocking with the aforementioned cylindrical crowns 15 and 16 which extend the circular peripheral edge of the upstream 12 and downstream 13 end walls. This connection by interlocking is locked by means of assembly collars 17 and 18.
  • the central tube 5, the outer tube 10, the end walls 12 and 13 and the two concentric tubes of the extensions 7 and 9 are made of metallic material, preferably stainless steel (for example of the 316L type) to suitably withstand corrosion and condensation. It is possible for this to use a metal sheet whose thickness is of the order of 0.4 to 2 mm.
  • the upstream section 5a and the downstream section 5b of the central tube 5 are juxtaposed and they extend together over the entire length L of the sound absorption chamber 11.
  • the length C of the upstream section 5a of the central tube 5 is preferably between half and 3/4 of the length L, the length D of the downstream section 5b occupying the rest of this length L.
  • the perforations 20 are adapted in size and number to allow the sound waves to penetrate as much as possible into the acoustic absorption chamber 11, while allowing the central tube 5 to correctly maintain the acoustic absorbent material 14.
  • the perforations 20 of the downstream section 5b of the central tube 5 are made homogeneously over the entire surface of the wall concerned, and they have a diameter which is preferably between 5 and 20 mm (more preferably between 10 and 15 mm). These perforations occupy 15 to 70% of the wall surface of the tube section 5b (preferably 45 to 60% of this wall surface).
  • the inner section 9a1 of the inner tube 9a in which the downstream end 8 of the central tube 5 is fitted, has openings or perforations 9a2.
  • These perforations 9a2 of the inner section 9a1 are adapted to limit (or avoid) the blocking of the perforations 20 of the downstream end of the central tube 5 and thus ensure that the corresponding perforated zone extends well to the end wall downstream 13.
  • the sound absorption chamber 11 is generally annular in shape with a constant section, and it is delimited by the central tube 5, the outer tube 10, the upstream end wall 12 and the downstream end wall 13.
  • This sound absorption chamber 11 here comprises an empty upstream part 11a, devoid of filling material, forming a cylindrical annular cavity, followed by a downstream part 11b which is filled with the acoustic absorptive material 14.
  • the upstream part 11a of the sound absorption chamber 11, of length E, extends from the upstream end wall 12 to a plane F perpendicular to the longitudinal axis A, located downstream of the aforementioned intermediate zone 19, separating the zone not perforated 5a of the perforated zone 5b of the central tube 5, and corresponding to the upstream end edge 14a of the sound absorption material 14.
  • the cavity-shaped upstream part 11a of the sound absorption chamber 11, of length E therefore comprises - an upstream part 11a', of length C, which surrounds the full upstream section 5a of the central tube 5, and - a downstream 11a", of length G, which surrounds an upstream part 5b1 of the perforated downstream section 5b of the central tube 5.
  • This cavity 11a of the sound absorption chamber 11 is delimited a/ by the upstream part of the outer tube 10, b/ by the upstream end edge 14a of the sound absorption material 14, c/ by the end wall upstream 12, and d/ by a part of the central tube 5 (comprising the unperforated upstream part 5a followed by the perforated upstream part 5b1 of the perforated downstream section 5b of the central tube 5).
  • the length G of this perforated upstream part 5b1 surrounded by the downstream cavity part 11a", between the aforementioned planes B and F, corresponds between 1/6th and 1/2 of the length E of the cavity 11a.
  • the acoustic absorbent material 14 is in the form of an annular cylinder delimited a/ by the upstream end edge 14a, extending in a plane perpendicular to the longitudinal axis A and corresponding to the aforementioned plane F located downstream of the intermediate zone 19, b/ by an upstream end edge 14b, extending in a plane perpendicular to the longitudinal axis A, arranged close to the downstream end wall 13 or resting against the latter, c/ by an outer cylindrical surface 14c, in contact with the inner face of the outer tube 10, and, d/ by an inner cylindrical surface 14d, in contact with the outer face of the central tube 5.
  • the length of the cylinder made of acoustic absorbent material 14, between its upstream 14a and downstream 14b end edges corresponds to the length H of the downstream part 11b of the acoustic absorption chamber 11, and the whole of this length is opposite of a perforated part of the central tube 5.
  • the acoustic absorbent material 14 here consists of high density mineral fibers, for example rock wool whose density is between 30 and 140 kg/m 3 , preferably between 60 and 120 kg/m 3 .
  • the length H of the downstream part 11b of the acoustic absorption chamber 11, filled with the acoustic absorptive material 14, corresponds between 1/3 and 2/3 of the length L of said chamber 11.
  • the length L of the sound absorption chamber 11 can be between 700 and 1000 mm, and its thickness between 100 and 150 mm; the diameter of the central tube 5 can, for its part, be between 130 and 600 mm.
  • the cylinder of acoustic absorbent material 14 is preferably produced by means of two complementary half-shells 141, 142, each half-cylindrical, as illustrated in the picture 2 . This feature facilitates the assembly and replacement of the acoustic absorbent material, in the event of degradation or fouling.
  • This cylinder 14 of acoustic absorbent material can be protected by a fiberglass fabric provided on the internal face of the acoustic absorbent material 14, pressed against the central tube 5.
  • the acoustic absorbent material 14 is held in position at its upstream end edge 14a by small retaining tabs 22 which extend in the plane F, perpendicular to the longitudinal axis A.
  • These retaining tabs 22 are advantageously obtained in the material of the central tube 5 by suitable cutting and folding at right angles. They can also be attached and fixed by welding.
  • the noise attenuator device 1 comprises a purge system 23 adapted to ensure the evacuation of the condensates.
  • This purge system 23 is formed of a purge orifice associated with a removable obturator plug, and it is arranged near the upstream extension 7 of the male type, here on the outer tube 10 next to the upstream end wall 12 .
  • this purge system 23 can be positioned on the upstream end wall 12.
  • the evacuation of the condensates can also be carried out by means of a suitable orifice (not shown), passing through the upstream end 6 of the central tube 5, as well as the inner section 7a1 of the inner tube 7a.
  • Such a noise attenuator device structure makes it possible to effectively absorb the sound waves emitted by the device 3, and which propagate in the smoke evacuation duct 2.
  • Such a device makes it possible to trap the sound waves by the acoustic absorptive material 14, and also by the cavity 11a, this effectively over a wide range of wave frequencies.
  • the positioning of the acoustic absorptive material 14 downstream of the cavity 11a also makes it possible to attenuate the noise regenerated in the absorber device 1, in particular in the case of rapid flow of gas flows.
  • the figures 5 and 6 illustrate another embodiment of a noise attenuator device according to the invention.
  • This noise attenuator device 1' has a structure very similar to that of the embodiment illustrated in the figures 1 to 4 . It also comprises an absorption core fitted inside the central tube, making it possible in particular to limit the air path in the case of large central tube diameters.
  • the noise attenuator device 1' therefore comprises a central tube 5 provided with two end extensions 7 and 9 and surrounded by an outer tube 10.
  • This outer tube 10 is assembled with the central tube 5 by the upstream end wall 12 and by the downstream end wall 13 to define the annular sound absorption chamber 11.
  • the upstream section 5a of the central tube 5 is solid (non-perforated) and it extends as far as the intermediate zone 19. This solid section 5a is extended by a perforated downstream section 5b.
  • a ring of acoustic absorbent material 14 fills the downstream part 11b of the acoustic absorption chamber 11, from the plane F located downstream of the aforementioned intermediate zone 19.
  • a complementary absorption core 24 is mounted inside the central tube 5, on the longitudinal axis A of the latter.
  • This inner absorption core 24 is in the general form of a cylinder whose diameter is less than the diameter of the central tube 5, assembled with the inner face of the latter by means of spacer tabs 25.
  • This absorption core 24 comprises a cylindrical outer casing 26 which is provided with perforations 27; this envelope 26 is filled with an acoustic absorbent material 28.
  • the outer casing 26 of the absorption core 24 is made of stainless steel, for example of the 316L type.
  • the perforations 27 are distributed evenly over the entire surface of the outer casing 26 and they occupy between 40 and 60% of the surface of this casing.
  • the acoustic absorbent material 28 preferably consists of rock wool whose density is between 30 and 140 kg/m 3 , preferably between 60 and 80 kg/m 3 .
  • At least the upstream end 29 of the absorption core 24 is in the shape of an ogive (or of a dome) to limit disturbances to the flow of smoke.
  • downstream end 30 of the absorption core 24 is also in the form of an ogive.
  • This absorption core 24 extends over part of the length of the central tube 5; preferably it extends inside the perforated downstream section 5b of said central tube 5. In this case, the absorption core 24 here extends over the entire or practically the entire length of this perforated downstream section 5b, and over the entire length occupied by the cylinder of acoustic absorptive core 14.
  • This absorption core 24 has the function and the advantage of adding absorptive material to compensate for the large internal diameter of the sound absorption device, in particular in the case of internal tubes having a diameter greater than or equal to 350 mm.
  • the figure 7 illustrates yet another embodiment of a noise attenuator device 1" in accordance with the invention.
  • This noise attenuator device 1" therefore comprises a central tube 5 provided with two end extensions 7 and 9 and surrounded by an outer tube 10.
  • This outer tube 10 is assembled with the central tube 5 by the upstream end wall 12 and by the downstream end wall 13 to define the annular chamber 11.
  • the central tube 5 comprises a non-perforated upstream section 5a up to the intermediate zone 19, followed by a perforated downstream section 5b.
  • a ring of acoustic absorbent material 14 fills the downstream part 11b of the absorption chamber 11.
  • an inspection hatch 31 is provided in the outer tube 10, opening into the upstream part 11a in the form of a cavity.
  • This inspection hatch 31 is formed of a cylindrical ferrule 32 fixed to the outer tube 10 (along an axis perpendicular to the axis of this outer tube 10), associated with an insulated removable plug 33.
  • a cutout/opening 34 is provided in the central part of the central tube 5 opposite the inspection hatch 31, to allow access to the interior of this central tube 5.
  • Such an inspection hatch 31 allows maintenance of the device, in particular when it is placed on conduits serving boilers using solid fuel such as wood.
  • This type of inspection hatch can of course also be fitted in attenuating devices with an absorption core, as illustrated in the figures 5 and 6 .
  • the upstream section 5a of the central tube 5 preferably has no perforations or openings. However, one or a few perforations/openings can be provided, depending on the needs, (as in the embodiment of the figure 7 ), without occupying a large wall surface. This perforated/open wall surface of the upstream section 5a will in any event be smaller than that of the downstream section 5b.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Physics & Mathematics (AREA)
  • Aviation & Aerospace Engineering (AREA)
  • Fluid Mechanics (AREA)
  • Acoustics & Sound (AREA)
  • Multimedia (AREA)
  • Exhaust Silencers (AREA)

Description

Domaine technique de l'inventionTechnical field of the invention

La présente invention concerne le domaine technique des dispositifs atténuateurs de bruit (encore appelés « silencieux ») pour les conduits d'évacuation de fumée équipant un appareil producteur de fumée, tel qu'un moteur de groupe électrogène, une chaudière, ou autre.The present invention relates to the technical field of noise attenuators (also called “silencers”) for the smoke evacuation ducts fitted to a smoke-producing device, such as a generator motor, a boiler, or the like.

Etat de la techniqueState of the art

En fonctionnement, certains appareils qui produisent des fumées (gaz de combustion, gaz d'échappement...), genre moteurs de groupe électrogène, chaudière ou autres, peuvent générer du bruit, en particulier du fait de la motorisation, du brûleur et/ou du ventilateur qui les équipe, ce bruit se propageant dans les conduits ou tubages associés, notamment dans les conduits d'évacuation des fumées.In operation, certain appliances that produce fumes (combustion gas, exhaust gas, etc.), such as generator motors, boilers or others, can generate noise, in particular due to the motorization, the burner and/or or of the fan which equips them, this noise being propagated in the associated ducts or casings, in particular in the smoke evacuation ducts.

Le niveau sonore de ce bruit est parfois important ; il est propre à chaque installation et se caractérise par une amplitude et une gamme de fréquence (entre quelques dizaines et quelques milliers de Hertz).The sound level of this noise is sometimes significant; it is specific to each installation and is characterized by an amplitude and a frequency range (between a few tens and a few thousand Hertz).

Ce bruit occasionne des nuisances dans l'environnement, que l'on cherche à réduire au moyen de dispositifs atténuateurs de bruit, encore appelés silencieux, placés sur le conduit d'évacuation de fumée, entre un tronçon amont et un tronçon aval de ce dernier.This noise causes nuisance in the environment, which it is sought to reduce by means of noise attenuating devices, also called silencers, placed on the smoke evacuation duct, between an upstream section and a downstream section of the latter. .

Il existe des dispositifs atténuateurs de bruit (ou silencieux) qui fonctionnent selon un principe dit « réactif », consistant à faire pénétrer les ondes sonores dans une cavité, de manière adaptée pour en changer la fréquence.There are noise attenuators (or silencers) which operate according to a so-called “reactive” principle, consisting in causing sound waves to penetrate into a cavity, in a suitable way to change its frequency.

Ces dispositifs ont une bonne efficacité sur les basses fréquences, de quelques dizaines à quelques centaines de Hertz (l'atténuation sonore peut aller de 5dB à 40dB jusqu'à 1000 Hertz), mais elle est relativement réduite pour ce qui concerne les fréquences supérieures à 1000 - 1500 Hertz (l'atténuation sonore est inférieure à 5dB au-delà de 2000 Hertz).These devices have good efficiency at low frequencies, from a few tens to a few hundred Hertz (sound attenuation can range from 5dB to 40dB up to 1000 Hertz), but it is relatively reduced for frequencies above 1000 - 1500 Hertz (sound attenuation is less than 5dB above 2000 Hertz).

On connait également des silencieux de type dit « absorptif » dans lesquels on utilise un matériau absorptif (en particulier des fibres minérales haute densité) pour chercher à absorber les ondes sonores.Silencers of the so-called “absorptive” type are also known in which an absorptive material (in particular high-density mineral fibers) is used to seek to absorb the sound waves.

En particulier, ces dispositifs de type « absorptif » comportent :

  • un tube central perforé, muni de prolongements amont et aval pour son raccordement à des tronçons amont et aval de conduit d'évacuation de fumée,
  • un tube extérieur qui ceinture le tube central perforé, pour définir entre eux une chambre d'absorption acoustique, et qui est raccordé à ce dernier par une paroi d'extrémité amont et par une paroi d'extrémité aval, et,
  • un matériau absorptif acoustique, placé dans la chambre d'absorption acoustique.
In particular, these “absorptive” type devices comprise:
  • a perforated central tube, provided with upstream and downstream extensions for its connection to upstream and downstream sections of the smoke evacuation duct,
  • an outer tube which surrounds the perforated central tube, to define between them a sound absorption chamber, and which is connected to the latter by an upstream end wall and by a downstream end wall, and,
  • an acoustic absorbent material, placed in the acoustic absorption chamber.

De tels dispositifs ont généralement une bonne efficacité pour l'absorption des ondes dans les hautes fréquences (jusqu'à 40dB d'absorption entre 1000 et 3000 Hertz), cette efficacité étant néanmoins réduite dans le domaine des basses fréquences (de l'ordre de quelques dB jusqu'à 400 - 500 Hertz).Such devices generally have a good efficiency for the absorption of waves in the high frequencies (up to 40dB of absorption between 1000 and 3000 Hertz), this efficiency being nevertheless reduced in the field of the low frequencies (of the order of a few dB up to 400 - 500 Hertz).

Le document EP 2 857 748 décrit de son côté un dispositif atténuateur de bruit utilisant à la fois le principe « réactif » et le principe « absorptif », de manière à chercher à bénéficier de leurs avantages respectifs.The document EP 2 857 748 describes for its part a noise attenuator device using both the “reactive” principle and the “absorptive” principle, so as to seek to benefit from their respective advantages.

Le dispositif atténuateur de bruit correspondant comprend un tube central qui est muni, tenant compte de la direction de déplacement des fumées, d'un prolongement amont adapté pour son raccordement à un tronçon de conduit de fumée amont, et d'un prolongement aval adapté pour son raccordement à un tronçon de conduit de fumée aval. Ce tube central comporte des perforations sur une partie de sa longueur et il est ceinturé par un tube extérieur pour définir entre eux une chambre d'absorption acoustique, lequel tube extérieur est raccordé audit tube central, toujours tenant compte de la direction de déplacement des fumées, par une paroi d'extrémité amont et par une paroi d'extrémité aval, qui délimitent la longueur de ladite chambre d'absorption acoustique. Cette chambre d'absorption acoustique est partiellement comblée, ici dans sa partie amont, par un matériau absorptif acoustique qui remplit son épaisseur entre le tube central et le tube extérieur.The corresponding noise attenuator device comprises a central tube which is provided, taking into account the direction of movement of the smoke, with an upstream extension suitable for its connection to an upstream flue section, and with a downstream extension suitable for its connection to a section of downstream flue. This central tube has perforations over part of its length and it is surrounded by an outer tube to define between them a sound absorption chamber, which outer tube is connected to said central tube, always taking into account the direction of movement of the fumes , by an upstream end wall and by a downstream end wall, which delimit the length of said acoustic absorption chamber. This acoustic absorption chamber is partially filled, here in its upstream part, by an acoustic absorbent material which fills its thickness between the central tube and the outer tube.

Les perforations du tube central sont prévues sur un tronçon amont ménagé en regard du matériau absorptif acoustique et aussi en regard d'une partie de la chambre d'absorption acoustique dépourvue dudit matériau absorptif acoustique.The perforations of the central tube are provided on an upstream section formed facing the acoustic absorptive material and also facing a part of the acoustic absorption chamber devoid of said acoustic absorptive material.

On obtient ainsi un dispositif atténuateur de bruit dont la partie absorptive est située en amont, suivie de la partie réactive située en aval.A noise attenuator device is thus obtained, the absorptive part of which is located upstream, followed by the reactive part located downstream.

Cependant, certaines applications génèrent des vitesses d'écoulement élevées dans le silencieux, et le bruit régénéré dans la partie réactive par cet écoulement rapide peut devenir non négligeable, limitant ainsi l'efficacité du dispositif.However, some applications generate high flow velocities in the silencer, and the noise regenerated in the reactive part by this fast flow can become significant, thus limiting the efficiency of the device.

Présentation de l'inventionPresentation of the invention

Afin de remédier à l'inconvénient précité de l'état de la technique, la présente invention propose un appareil producteur de fumée (tel qu'un moteur de groupe électrogène, une chaudière ou autre), défini dans la revendication 1.In order to remedy the aforementioned drawback of the state of the art, the present invention proposes a smoke-producing apparatus (such as a generator set engine, a boiler or the like), defined in claim 1.

La partie amont du dispositif atténuateur de bruit comporte une cavité ayant pour effet, notamment, de modifier la fréquence des ondes, et la partie aval a une action d'absorption des ondes, grâce au matériau absorptif acoustique, pour en atténuer le niveau sonore.
La partie absorptive se situe ainsi en sortie du dispositif atténuateur de bruit, en aval de la partie réactive, et elle vient atténuer le bruit régénéré et par conséquent augmenter la performance du silencieux.
La cavité amont de la chambre d'absorption acoustique est délimitée, d'un côté, par la tranche du matériau absorptif acoustique, qui assure aussi à ce niveau une fonction d'absorption des ondes sonores, contribuant à améliorer l'efficacité du dispositif.The upstream part of the noise attenuator device comprises a cavity having the effect, in particular, of modifying the frequency of the waves, and the downstream part has an action of absorbing the waves, thanks to the acoustic absorptive material, in order to attenuate the sound level.
The absorptive part is thus located at the output of the noise attenuator device, downstream of the reactive part, and it attenuates the regenerated noise and consequently increases the performance of the silencer.
The cavity upstream of the sound absorption chamber is delimited, on one side, by the edge of the sound absorbing material, which also performs at this level a sound wave absorption function, contributing to improving the efficiency of the device.

D'autres caractéristiques non limitatives et avantageuses de l'appareil conforme à l'invention, prises individuellement ou selon toutes les combinaisons techniquement possibles, sont les suivantes :

  • le tube central du dispositif atténuateur de bruit est de section circulaire et il comporte un axe longitudinal sur lequel sont centrés lesdits prolongements amont et aval ; ladite chambre d'absorption acoustique est de section générale annulaire cylindrique, d'épaisseur constante, centrée sur l'axe longitudinal dudit tube central.
  • le matériau absorptif acoustique consiste en de la laine de roche dont la densité est comprise entre 30 et 140 kg/m3 de préférence comprise entre 60 et 120 kg/m3.
  • le diamètre du tube central est compris entre 130 et 600 mm, l'épaisseur de la chambre d'absorption acoustique est comprise entre 100 et 150 mm, et la longueur de cette chambre d'absorption acoustique est comprise entre 700 et 1000 mm.
  • le matériau absorptif acoustique s'étend entre le 1/3 et les 2/3 de la longueur de la chambre d'absorption acoustique ; en outre, la partie amont perforée du tube central qui est ceinturée par la partie aval de cavité, s'étend entre le 1/6ème et la 1/2 de la longueur de ladite cavité.
  • les perforations du tronçon aval du tube central ont un diamètre compris entre 5 et 20 mm, et elles occupent 15 à 70 % de la surface de paroi dudit tronçon aval de tube central.
  • le tube extérieur du dispositif atténuateur de bruit est solidarisé de manière amovible avec des couronnes cylindriques qui prolongent lesdites parois d'extrémité amont et aval, au moyen de colliers de serrage.
  • le dispositif atténuateur de bruit comporte un noyau d'absorption intérieur de forme générale cylindrique, monté co-axialement au tube central, à l'intérieur de ce dernier, lequel noyau (i) a un diamètre inférieur au diamètre dudit tube central, (ii) comporte une extrémité amont, orientée vers ledit prolongement amont, en forme d'ogive, et (iii) comporte une enveloppe externe munie de perforations et remplie d'un matériau absorptif acoustique. De préférence, la majeure partie de la longueur de ce noyau d'absorption s'étend à l'intérieur du tronçon aval perforé du tube central.
  • le dispositif atténuateur de bruit comporte une trappe de visite ménagée dans le tube extérieur, associée à un bouchon amovible.
  • la cavité de ladite chambre d'absorption acoustique est délimitée, d'un côté, par la bordure d'extrémité amont du matériau absorptif.
  • le prolongement amont du tube central du dispositif atténuateur de bruit est en forme d'embout mâle adapté pour coopérer avec un embout femelle d'un tronçon de conduit de fumée amont, et le prolongement aval du tube central du dispositif atténuateur de bruit est en forme d'embout femelle adapté pour coopérer avec un embout mâle d'un tronçon de conduit de fumée aval.
  • le prolongement aval du tube central du dispositif atténuateur de bruit comporte un tronçon de tube intérieur, qui s'étend vers l'intérieur, et qui reçoit l'extrémité aval dudit tube central par emmanchement, lequel tronçon de tube intérieur est muni de perforations.
Other non-limiting and advantageous characteristics of the device according to the invention, taken individually or according to all the technically possible combinations, are the following:
  • the central tube of the noise attenuator device is of circular section and it comprises a longitudinal axis on which the said upstream and downstream extensions are centered; said sound absorption chamber is of generally cylindrical annular section, of constant thickness, centered on the longitudinal axis of said central tube.
  • the acoustic absorbent material consists of rock wool, the density of which is between 30 and 140 kg/m 3 , preferably between 60 and 120 kg/m 3 .
  • the diameter of the central tube is between 130 and 600 mm, the thickness of the sound absorption chamber is between 100 and 150 mm, and the length of this sound absorption chamber is between 700 and 1000 mm.
  • the acoustic absorbent material extends between 1/3 and 2/3 of the length of the acoustic absorption chamber; in addition, the perforated upstream part of the central tube which is surrounded by the downstream part of the cavity, extends between 1/6th and 1/2 of the length of said cavity.
  • the perforations of the downstream section of the central tube have a diameter of between 5 and 20 mm, and they occupy 15 to 70% of the wall surface of said downstream section of the central tube.
  • the outer tube of the noise attenuator device is secured in a removable manner with cylindrical crowns which extend said upstream and downstream end walls, by means of clamps.
  • the noise attenuator device comprises an internal absorption core of generally cylindrical shape, mounted coaxially to the central tube, inside the latter, which core (i) has a diameter smaller than the diameter of said central tube, (ii ) comprises an upstream end, oriented towards said upstream extension, in the shape of an ogive, and (iii) comprises an outer casing provided with perforations and filled with an acoustic absorbent material. Preferably, the major part of the length of this absorption core extends inside the perforated downstream section of the central tube.
  • the noise attenuator device comprises an inspection hatch formed in the outer tube, associated with a removable plug.
  • the cavity of said acoustic absorption chamber is delimited, on one side, by the upstream end edge of the absorptive material.
  • the upstream extension of the central tube of the noise attenuator device is in the form of a male end adapted to cooperate with a female end of an upstream flue section, and the downstream extension of the central tube of the noise attenuator device is in the form female end piece adapted to cooperate with a male end piece of a downstream flue section.
  • the downstream extension of the central tube of the noise attenuator device comprises an inner tube section, which extends inwards, and which receives the downstream end of said central tube by fitting, which inner tube section is provided with perforations.

Bien entendu, les différentes caractéristiques, variantes et formes de réalisation de l'invention peuvent être associées les unes avec les autres selon diverses combinaisons dans la mesure où elles ne sont pas incompatibles ou exclusives les unes des autres.Of course, the different characteristics, variants and embodiments of the invention can be associated with each other in various combinations insofar as they are not incompatible or exclusive of each other.

Description détaillée de l'inventionDetailed description of the invention

De plus, diverses autres caractéristiques de l'invention ressortent de la description annexée effectuée en référence aux dessins qui illustrent des formes, non limitatives, de réalisation de l'invention et où :

  • La figure 1 est une vue en perspective d'un premier mode de réalisation d'un dispositif atténuateur de bruit conforme à l'invention ;
  • La figure 2 est une vue en perspective éclatée du dispositif atténuateur de bruit illustré sur la figure 1 ;
  • La figure 3 est une vue de face de l'extrémité amont du dispositif atténuateur de bruit illustré sur les figures 1 et 2 ;
  • La figure 4 est une vue en coupe longitudinale du dispositif atténuateur de bruit, selon le plan de coupe 4-4 de la figure 3 ;
  • La figure 5 est une vue de face de l'extrémité aval d'un second mode de réalisation d'un dispositif atténuateur de bruit conforme à l'invention ;
  • La figure 6 est une vue en coupe longitudinale du dispositif atténuateur de bruit illustré sur la figure 5, selon le plan de coupe 6-6 de cette figure 5 ;
  • La figure 7 est une vue en coupe longitudinale d'une variante de réalisation d'un dispositif atténuateur de bruit selon l'invention.
In addition, various other characteristics of the invention emerge from the appended description made with reference to the drawings which illustrate non-limiting forms of embodiment of the invention and where:
  • The figure 1 is a perspective view of a first embodiment of a noise attenuator device according to the invention;
  • The picture 2 is an exploded perspective view of the noise attenuator device shown in the figure 1 ;
  • The picture 3 is a front view of the upstream end of the noise attenuator device illustrated in the figures 1 and 2 ;
  • The figure 4 is a longitudinal sectional view of the noise attenuator device, according to section plane 4-4 of the picture 3 ;
  • The figure 5 is a front view of the downstream end of a second embodiment of a noise attenuator device according to the invention;
  • The figure 6 is a longitudinal sectional view of the noise attenuator device illustrated in the figure 5 , according to section plan 6-6 of this figure 5 ;
  • The figure 7 is a view in longitudinal section of an alternative embodiment of a noise attenuator device according to the invention.

Il est à noter que, sur ces figures, les éléments structurels et/ou fonctionnels communs aux différentes variantes peuvent présenter les mêmes références.It should be noted that, in these figures, the structural and/or functional elements common to the different variants may have the same references.

Les figures 1 à 4 illustrent un premier mode de réalisation d'un dispositif atténuateur de bruit 1 selon l'invention, destiné à être intégré au conduit 2 d'évacuation de fumée équipant un appareil producteur de fumées 3, par exemple un moteur ou une chaudière.The figures 1 to 4 illustrate a first embodiment of a noise attenuator device 1 according to the invention, intended to be integrated into the smoke evacuation duct 2 fitted to a smoke-producing device 3, for example an engine or a boiler.

Ce dispositif atténuateur de bruit 1 est en particulier ici agencé pour venir s'intégrer entre un tronçon amont 2a et un tronçon aval 2b du conduit de fumée 2 (figure 4) pour constituer une partie de ce conduit 2 et également pour remplir sa fonction de réduction du bruit provenant de l'appareil 3.This noise attenuator device 1 is in particular here arranged to be integrated between an upstream section 2a and a downstream section 2b of the flue 2 ( figure 4 ) to form part of this duct 2 and also to fulfill its function of reducing the noise coming from the device 3.

Sur la figure 4, l'appareil 3 est simplement schématisée en pointillés à l'extrémité amont du tronçon de conduit amont 2a.On the figure 4 , the device 3 is simply shown schematically in dotted lines at the upstream end of the upstream pipe section 2a.

Toujours sur la figure 4, on a illustré par la flèche d'orientation 4 le sens amont/aval de déplacement des fumées et des ondes sonores dans le conduit 2 (et donc également dans le dispositif atténuateur de bruit 1).Always on the figure 4 , the orientation arrow 4 illustrates the upstream/downstream direction of movement of the fumes and the sound waves in the duct 2 (and therefore also in the noise attenuator device 1).

Ce sens amont/aval est utilisé dans la suite de la description pour définir certaines parties structurelles du dispositif atténuateur de bruit 1.This upstream/downstream direction is used in the remainder of the description to define certain structural parts of the noise attenuator device 1.

Le dispositif atténuateur de bruit 1 se présente sous une forme générale cylindrique comprenant :

  • un tube central 5 de section circulaire, d'axe longitudinal A (disposé ici horizontalement), dont l'extrémité amont 6 comporte un prolongement 7 pour son raccordement au tronçon de conduit amont 2a, et dont l'extrémité aval 8 comporte un prolongement 9 pour son raccordement au tronçon de conduit aval 2b ;
  • un tube extérieur 10, de section circulaire, qui ceinture le tube central 5 de manière concentrique et à distance de ce dernier pour définir, entre eux, une chambre annulaire 11, dite « chambre d'absorption acoustique » ; ce tube extérieur 10 est raccordé au tube central 5 par une paroi d'extrémité amont 12 et par une paroi d'extrémité aval 13 ; et
  • un matériau absorptif acoustique 14 destiné à combler une partie du volume de la chambre d'absorption acoustique 11.
The noise attenuator device 1 is in a generally cylindrical shape comprising:
  • a central tube 5 of circular section, of longitudinal axis A (disposed here horizontally), the upstream end 6 of which comprises an extension 7 for its connection to the upstream duct section 2a, and whose downstream end 8 has an extension 9 for its connection to the downstream duct section 2b;
  • an outer tube 10, of circular section, which surrounds the central tube 5 concentrically and at a distance from the latter to define, between them, an annular chamber 11, called the “sound absorption chamber”; this outer tube 10 is connected to the central tube 5 by an upstream end wall 12 and by a downstream end wall 13; and
  • an acoustic absorbent material 14 intended to fill part of the volume of the acoustic absorption chamber 11.

Les parois d'extrémité amont 12 et aval 13 s'étendent parallèlement l'une à l'autre. Elles ont chacune une forme annulaire plane centrée sur l'axe longitudinal A, et elles définissent entre elles la longueur L de la chambre d'absorption acoustique 11.The upstream 12 and downstream 13 end walls extend parallel to each other. They each have a planar annular shape centered on the longitudinal axis A, and they define between them the length L of the sound absorption chamber 11.

Des couronnes cylindriques, respectivement 15 et 16, prolongent la bordure périphérique circulaire des parois d'extrémité amont 12 et aval 13, solidarisées avec ces dernières par soudage. Ces couronnes cylindriques 15 et 16 s'étendent vers l'intérieur, c'est-à-dire qu'elles sont orientées en regard l'une de l'autre.Cylindrical rings, 15 and 16 respectively, extend the circular peripheral edge of the upstream 12 and downstream 13 end walls, secured to the latter by welding. These cylindrical crowns 15 and 16 extend inwards, that is to say they are oriented opposite one another.

D'autre part, les prolongements amont 7 et aval 9 consistent en des structures cylindriques comportant une paroi isolée, formée de deux tubes concentriques qui prennent en sandwich un matériau isolant.On the other hand, the upstream 7 and downstream 9 extensions consist of cylindrical structures comprising an insulated wall, formed by two concentric tubes which sandwich an insulating material.

Le prolongement amont 7 du tube central 5 est en forme d'embout mâle qui est adapté pour coopérer avec un embout femelle du tronçon de conduit de fumée amont 2a, et son prolongement aval 9 est en forme d'embout femelle adapté pour coopérer avec un embout mâle du tronçon de conduit de fumée aval 2b.The upstream extension 7 of the central tube 5 is in the form of a male end piece which is adapted to cooperate with a female end piece of the upstream flue section 2a, and its downstream extension 9 is in the form of a female end piece adapted to cooperate with a male end of the downstream flue section 2b.

Ces prolongements amont 7 et aval 9 s'étendent principalement vers l'extérieur à partir des parois d'extrémité 12 et 13, leur tube intérieur 7a, 9a étant solidarisé par soudage avec la bordure de l'orifice central desdites parois d'extrémité 12, 13, et leur tube extérieur 7b, 9b étant solidarisé par soudage contre la face externe desdites parois d'extrémité 12, 13.These upstream 7 and downstream 9 extensions extend mainly outwards from the end walls 12 and 13, their inner tube 7a, 9a being joined by welding with the edge of the central orifice of said end walls 12 , 13, and their outer tube 7b, 9b being secured by welding against the outer face of said end walls 12, 13.

Un tronçon intérieur 7a1, 9a1 des tubes intérieurs 7a, 9a des prolongements amont 7 et aval 9 s'étend vers l'intérieur de la chambre d'absorption acoustique 11. Ces deux tronçon intérieurs 7a1, 9a1 s'étendent en regard l'un de l'autre, et ils reçoivent par simple emmanchement les extrémités amont 6 et aval 8 du tube central 5.An inner section 7a1, 9a1 of the inner tubes 7a, 9a of the upstream 7 and downstream 9 extensions extends towards the inside of the sound absorption chamber 11. These two inner sections 7a1, 9a1 extend opposite one on the other, and they receive by simple fitting the upstream 6 and downstream 8 ends of the central tube 5.

Le tube extérieur 10 est constitué par une virole cylindrique obtenue à partir d'une plaque cintrée, dont les deux bordures longitudinales en regard, suite au cintrage, sont assemblées entre elles par soudage, et dont les extrémités amont et aval sont solidarisées par emboitement amovible avec les couronnes cylindriques 15 et 16 précitées qui prolongent la bordure périphérique circulaire des parois d'extrémité amont 12 et aval 13. Cette solidarisation par emboitement est verrouillée au moyen de colliers d'assemblage 17 et 18.The outer tube 10 consists of a cylindrical shell obtained from a curved plate, the two facing longitudinal edges of which, following the bending, are assembled together by welding, and the upstream and downstream ends of which are secured by removable interlocking with the aforementioned cylindrical crowns 15 and 16 which extend the circular peripheral edge of the upstream 12 and downstream 13 end walls. This connection by interlocking is locked by means of assembly collars 17 and 18.

Le tube central 5, le tube extérieur 10, les parois d'extrémité 12 et 13 et les deux tubes concentriques des prolongements 7 et 9 sont réalisés en matériau métallique, de préférence en acier inoxydable (par exemple du type 316L) pour résister convenablement à la corrosion et à la condensation. On peut pour cela utiliser une tôle métallique dont l'épaisseur est de l'ordre de 0,4 à 2 mm.The central tube 5, the outer tube 10, the end walls 12 and 13 and the two concentric tubes of the extensions 7 and 9 are made of metallic material, preferably stainless steel (for example of the 316L type) to suitably withstand corrosion and condensation. It is possible for this to use a metal sheet whose thickness is of the order of 0.4 to 2 mm.

Comme on peut le voir sur les figures 2 et 4, le tube central 5 comporte :

  • un tronçon amont 5a, non perforé, qui s'étend depuis la paroi d'extrémité amont 12 jusqu'à une zone intermédiaire 19 située entre lesdites parois amont 12 et aval 13, cette zone intermédiaire 19 correspondant ici à un plan B perpendiculaire à l'axe longitudinal A, et
  • un tronçon aval 5b, muni de perforations 20, qui s'étend depuis ladite zone intermédiaire 19 jusqu'à la paroi d'extrémité aval 13.
As can be seen on the figure 2 and 4 , the central tube 5 comprises:
  • an upstream section 5a, non-perforated, which extends from the upstream end wall 12 to an intermediate zone 19 located between said upstream 12 and downstream 13 walls, this intermediate zone 19 here corresponding to a plane B perpendicular to the longitudinal axis A, and
  • a downstream section 5b, provided with perforations 20, which extends from said intermediate zone 19 to the downstream end wall 13.

Le tronçon amont 5a et le tronçon aval 5b du tube central 5 sont juxtaposés et ils s'étendent ensemble sur toute la longueur L de la chambre d'absorption acoustique 11.The upstream section 5a and the downstream section 5b of the central tube 5 are juxtaposed and they extend together over the entire length L of the sound absorption chamber 11.

La longueur C du tronçon amont 5a du tube central 5 est de préférence comprise entre la moitié et les 3/4 de la longueur L, la longueur D du tronçon aval 5b occupant le reste de cette longueur L.The length C of the upstream section 5a of the central tube 5 is preferably between half and 3/4 of the length L, the length D of the downstream section 5b occupying the rest of this length L.

Les perforations 20 sont adaptées en dimensions et nombre pour laisser pénétrer au maximum les ondes sonores dans la chambre d'absorption acoustique 11, tout en permettant au tube central 5 de maintenir correctement le matériau absorptif acoustique 14.The perforations 20 are adapted in size and number to allow the sound waves to penetrate as much as possible into the acoustic absorption chamber 11, while allowing the central tube 5 to correctly maintain the acoustic absorbent material 14.

Pour cela, les perforations 20 du tronçon aval 5b du tube central 5 sont réalisées de manière homogène sur toute la surface de paroi concernée, et elles ont un diamètre qui est de préférence compris entre 5 et 20 mm (encore de préférence compris entre 10 et 15 mm). Ces perforations occupent 15 à 70 % de la surface de paroi du tronçon de tube 5b (de préférence 45 à 60 % de cette surface de paroi).For this, the perforations 20 of the downstream section 5b of the central tube 5 are made homogeneously over the entire surface of the wall concerned, and they have a diameter which is preferably between 5 and 20 mm (more preferably between 10 and 15 mm). These perforations occupy 15 to 70% of the wall surface of the tube section 5b (preferably 45 to 60% of this wall surface).

Sur la figure 4 en particulier, on remarque que le tronçon intérieur 9a1 du tube intérieur 9a, dans lequel vient s'emmancher l'extrémité aval 8 du tube central 5, comporte des ouvertures ou perforations 9a2.
Ces perforations 9a2 du tronçon intérieur 9a1 sont adaptées pour limiter (ou éviter) l'obturation des perforations 20 de l'extrémité aval du tube central 5 et assurer ainsi que la zone perforée correspondante s'étende bien jusqu'à la paroi d'extrémité aval 13.On the figure 4 in particular, it is noted that the inner section 9a1 of the inner tube 9a, in which the downstream end 8 of the central tube 5 is fitted, has openings or perforations 9a2.
These perforations 9a2 of the inner section 9a1 are adapted to limit (or avoid) the blocking of the perforations 20 of the downstream end of the central tube 5 and thus ensure that the corresponding perforated zone extends well to the end wall downstream 13.

La chambre d'absorption acoustique 11 est de forme générale annulaire de section constante, et elle est délimitée par le tube central 5, le tube extérieur 10, la paroi d'extrémité amont 12 et la paroi d'extrémité aval 13.The sound absorption chamber 11 is generally annular in shape with a constant section, and it is delimited by the central tube 5, the outer tube 10, the upstream end wall 12 and the downstream end wall 13.

Cette chambre d'absorption acoustique 11 comporte ici une partie amont 11a vide, dépourvue de matériau de comblement, formant une cavité annulaire cylindrique, suivie d'une partie aval 11b qui est comblée par le matériau absorptif acoustique 14. La partie amont 11a de la chambre d'absorption acoustique 11, de longueur E, s'étend depuis la paroi d'extrémité amont 12 jusqu'à un plan F perpendiculaire à l'axe longitudinal A, situé en aval de la zone intermédiaire 19 précitée, séparant la zone non perforée 5a de la zone perforée 5b du tube central 5, et correspondant à la bordure d'extrémité amont 14a du matériau d'absorption acoustique 14.This sound absorption chamber 11 here comprises an empty upstream part 11a, devoid of filling material, forming a cylindrical annular cavity, followed by a downstream part 11b which is filled with the acoustic absorptive material 14. The upstream part 11a of the sound absorption chamber 11, of length E, extends from the upstream end wall 12 to a plane F perpendicular to the longitudinal axis A, located downstream of the aforementioned intermediate zone 19, separating the zone not perforated 5a of the perforated zone 5b of the central tube 5, and corresponding to the upstream end edge 14a of the sound absorption material 14.

La partie amont 11a en forme de cavité de la chambre d'absorption acoustique 11, de longueur E, comporte donc - une partie amont 11a', de longueur C, qui ceinture le tronçon amont plein 5a du tube central 5, et - une partie aval 11a", de longueur G, qui ceinture une partie amont 5b1 du tronçon aval perforé 5b du tube central 5.The cavity-shaped upstream part 11a of the sound absorption chamber 11, of length E, therefore comprises - an upstream part 11a', of length C, which surrounds the full upstream section 5a of the central tube 5, and - a downstream 11a", of length G, which surrounds an upstream part 5b1 of the perforated downstream section 5b of the central tube 5.

Cette cavité 11a de la chambre d'absorption acoustique 11 est délimitée a/ par la partie amont du tube extérieur 10, b/ par la bordure d'extrémité amont 14a du matériau d'absorption acoustique 14, c/ par la paroi d'extrémité amont 12, et d/ par une partie du tube central 5 (comprenant la partie amont non perforée 5a suivie de la partie amont perforée 5b1 du tronçon aval perforé 5b du tube central 5).This cavity 11a of the sound absorption chamber 11 is delimited a/ by the upstream part of the outer tube 10, b/ by the upstream end edge 14a of the sound absorption material 14, c/ by the end wall upstream 12, and d/ by a part of the central tube 5 (comprising the unperforated upstream part 5a followed by the perforated upstream part 5b1 of the perforated downstream section 5b of the central tube 5).

La longueur G de cette partie amont perforée 5b1 ceinturée par la partie aval de cavité 11a", entre les plans B et F précités, correspond entre le 1/6ème et la 1/2 de la longueur E de la cavité 11a.The length G of this perforated upstream part 5b1 surrounded by the downstream cavity part 11a", between the aforementioned planes B and F, corresponds between 1/6th and 1/2 of the length E of the cavity 11a.

Le matériau absorptif acoustique 14 se présente sous la forme d'un cylindre annulaire délimité a/ par la bordure d'extrémité amont 14a, s'étendant dans un plan perpendiculaire à l'axe longitudinal A et correspondant au plan précité F situé en aval de la zone intermédiaire 19, b/ par une bordure d'extrémité amont 14b, s'étendant dans un plan perpendiculaire à l'axe longitudinal A, disposée à proximité de la paroi d'extrémité aval 13 ou en appui contre cette dernière, c/ par une surface cylindrique extérieure 14c, en contact avec la face interne du tube extérieur 10, et, d/ par une surface cylindrique intérieure 14d, en contact avec la face externe du tube central 5.
La longueur du cylindre en matériau absorptif acoustique 14, entre ses bordures d'extrémité amont 14a et aval 14b correspond à la longueur H de la partie aval 11b de la chambre d'absorption acoustique 11, et l'intégralité de cette longueur est en regard d'une partie perforée du tube central 5.The acoustic absorbent material 14 is in the form of an annular cylinder delimited a/ by the upstream end edge 14a, extending in a plane perpendicular to the longitudinal axis A and corresponding to the aforementioned plane F located downstream of the intermediate zone 19, b/ by an upstream end edge 14b, extending in a plane perpendicular to the longitudinal axis A, arranged close to the downstream end wall 13 or resting against the latter, c/ by an outer cylindrical surface 14c, in contact with the inner face of the outer tube 10, and, d/ by an inner cylindrical surface 14d, in contact with the outer face of the central tube 5.
The length of the cylinder made of acoustic absorbent material 14, between its upstream 14a and downstream 14b end edges corresponds to the length H of the downstream part 11b of the acoustic absorption chamber 11, and the whole of this length is opposite of a perforated part of the central tube 5.

Le matériau absorptif acoustique 14 consiste ici en des fibres minérales à haute densité, par exemple de la laine de roche dont la densité est comprise entre 30 et 140 kg/m3, de préférence comprise entre 60 et 120 kg/m3.The acoustic absorbent material 14 here consists of high density mineral fibers, for example rock wool whose density is between 30 and 140 kg/m 3 , preferably between 60 and 120 kg/m 3 .

La longueur H de la partie aval 11b de la chambre d'absorption acoustique 11, comblée par le matériau absorptif acoustique 14, correspond entre le 1/3 et les 2/3 de la longueur L de ladite chambre 11.The length H of the downstream part 11b of the acoustic absorption chamber 11, filled with the acoustic absorptive material 14, corresponds between 1/3 and 2/3 of the length L of said chamber 11.

D'une manière générale, la longueur L de la chambre d'absorption acoustique 11 peut être comprise entre 700 et 1000 mm, et son épaisseur comprise entre 100 et 150 mm ; le diamètre du tube central 5 peut, de son côté, être compris entre 130 et 600 mm.In general, the length L of the sound absorption chamber 11 can be between 700 and 1000 mm, and its thickness between 100 and 150 mm; the diameter of the central tube 5 can, for its part, be between 130 and 600 mm.

Le cylindre de matériau absorptif acoustique 14 est de préférence réalisé au moyen de deux demi-coques complémentaires 141, 142, chacune demi-cylindrique, tel qu'illustré sur la figure 2. Cette particularité permet de faciliter le montage et le remplacement du matériau absorptif acoustique, en cas de dégradation ou d'encrassement. Ce cylindre 14 en matériau absorptif acoustique peut être protégé par un tissu de fibre de verre prévu sur la face interne du matériau absorptif acoustique 14, plaqué contre le tube central 5.The cylinder of acoustic absorbent material 14 is preferably produced by means of two complementary half-shells 141, 142, each half-cylindrical, as illustrated in the picture 2 . This feature facilitates the assembly and replacement of the acoustic absorbent material, in the event of degradation or fouling. This cylinder 14 of acoustic absorbent material can be protected by a fiberglass fabric provided on the internal face of the acoustic absorbent material 14, pressed against the central tube 5.

Sur les figures 2 et 4 on remarque que le matériau absorptif acoustique 14 est maintenu en position au niveau de sa bordure d'extrémité amont 14a par des petites pattes de maintien 22 qui s'étendent dans le plan F, perpendiculairement à l'axe longitudinal A. Ces pattes de maintien 22 sont avantageusement obtenues dans la matière du tube central 5 par découpe adaptée et pliage à l'équerre.
Elles peuvent aussi être rapportées et fixées par soudage.On the figure 2 and 4 it is noted that the acoustic absorbent material 14 is held in position at its upstream end edge 14a by small retaining tabs 22 which extend in the plane F, perpendicular to the longitudinal axis A. These retaining tabs 22 are advantageously obtained in the material of the central tube 5 by suitable cutting and folding at right angles.
They can also be attached and fixed by welding.

On notera également que le dispositif atténuateur de bruit 1 comprend un système de purge 23 adapté pour assurer l'évacuation des condensats.
Ce système de purge 23 est formé d'un orifice de purge associé à un bouchon obturateur amovible, et il est aménagé à proximité du prolongement amont 7 de type mâle, ici sur le tube extérieur 10 à côté de la paroi d'extrémité amont 12.
Dans le cas d'une pose à la verticale du dispositif atténuateur de bruit, ce système de purge 23 peut être positionné sur la paroi d'extrémité amont 12.
L'évacuation des condensats peut aussi être réalisée au moyen d'un orifice adapté (non représenté), traversant l'extrémité amont 6 du tube central 5, ainsi que le tronçon intérieur 7a1 du tube intérieur 7a.It will also be noted that the noise attenuator device 1 comprises a purge system 23 adapted to ensure the evacuation of the condensates.
This purge system 23 is formed of a purge orifice associated with a removable obturator plug, and it is arranged near the upstream extension 7 of the male type, here on the outer tube 10 next to the upstream end wall 12 .
In the case of a vertical installation of the noise attenuator device, this purge system 23 can be positioned on the upstream end wall 12.
The evacuation of the condensates can also be carried out by means of a suitable orifice (not shown), passing through the upstream end 6 of the central tube 5, as well as the inner section 7a1 of the inner tube 7a.

Une telle structure de dispositif atténuateur de bruit permet d'absorber efficacement les ondes sonores émises par l'appareil 3, et qui se propagent dans le conduit d'évacuation de fumée 2.Such a noise attenuator device structure makes it possible to effectively absorb the sound waves emitted by the device 3, and which propagate in the smoke evacuation duct 2.

Un tel dispositif permet de piéger les ondes sonores par le matériau absorptif acoustique 14, et également par la cavité 11a, cela de manière efficace sur une large plage de fréquences d'ondes.Such a device makes it possible to trap the sound waves by the acoustic absorptive material 14, and also by the cavity 11a, this effectively over a wide range of wave frequencies.

Le positionnement du matériau absorptif acoustique 14 en aval de la cavité 11a permet également d'atténuer le bruit régénéré dans le dispositif absorbeur 1, en particulier dans le cas d'écoulement rapide des flux gazeux.The positioning of the acoustic absorptive material 14 downstream of the cavity 11a also makes it possible to attenuate the noise regenerated in the absorber device 1, in particular in the case of rapid flow of gas flows.

Les figures 5 et 6 illustrent un autre mode de réalisation d'un dispositif atténuateur de bruit conforme à l'invention.The figures 5 and 6 illustrate another embodiment of a noise attenuator device according to the invention.

Ce dispositif atténuateur de bruit 1' a une structure très proche de celle du mode de réalisation illustré sur les figures 1 à 4. Il comporte en plus un noyau d'absorption aménagé à l'intérieur du tube central, permettant en particulier de limiter la voie d'air dans le cas de grands diamètres de tube central.This noise attenuator device 1' has a structure very similar to that of the embodiment illustrated in the figures 1 to 4 . It also comprises an absorption core fitted inside the central tube, making it possible in particular to limit the air path in the case of large central tube diameters.

Dans la description qui suit, les parties structurelles communes au mode de réalisation des figures 1 à 4 conservent les mêmes repères, par mesure de simplification.In the following description, the structural parts common to the embodiment of the figures 1 to 4 retain the same references, for simplicity.

Le dispositif atténuateur de bruit 1' comporte donc un tube central 5 muni des deux prolongements d'extrémité 7 et 9 et ceinturé par un tube extérieur 10.The noise attenuator device 1' therefore comprises a central tube 5 provided with two end extensions 7 and 9 and surrounded by an outer tube 10.

Ce tube extérieur 10 est assemblé avec le tube central 5 par la paroi d'extrémité amont 12 et par la paroi d'extrémité aval 13 pour définir la chambre annulaire d'absorption acoustique 11.This outer tube 10 is assembled with the central tube 5 by the upstream end wall 12 and by the downstream end wall 13 to define the annular sound absorption chamber 11.

Ici encore, le tronçon amont 5a du tube central 5 est plein (non perforé) et il s'étend jusqu'à la zone intermédiaire 19. Ce tronçon plein 5a se prolonge par un tronçon aval 5b perforé.Here again, the upstream section 5a of the central tube 5 is solid (non-perforated) and it extends as far as the intermediate zone 19. This solid section 5a is extended by a perforated downstream section 5b.

D'autre part, une couronne de matériau absorptif acoustique 14 comble la partie aval 11b de la chambre d'absorption acoustique 11, à partir du plan F situé en aval de la zone intermédiaire 19 précitée.On the other hand, a ring of acoustic absorbent material 14 fills the downstream part 11b of the acoustic absorption chamber 11, from the plane F located downstream of the aforementioned intermediate zone 19.

Dans ce mode de réalisation, un noyau d'absorption complémentaire 24 est monté à l'intérieur du tube central 5, sur l'axe longitudinal A de ce dernier.In this embodiment, a complementary absorption core 24 is mounted inside the central tube 5, on the longitudinal axis A of the latter.

Ce noyau d'absorption intérieur 24 se présente sous la forme générale d'un cylindre dont le diamètre est inférieur au diamètre du tube central 5, assemblé avec la face intérieure de ce dernier au moyen de pattes entretoises 25.This inner absorption core 24 is in the general form of a cylinder whose diameter is less than the diameter of the central tube 5, assembled with the inner face of the latter by means of spacer tabs 25.

Ce noyau d'absorption 24 comporte une enveloppe externe cylindrique 26 qui est munie de perforations 27 ; cette enveloppe 26 est remplie par un matériau absorptif acoustique 28.This absorption core 24 comprises a cylindrical outer casing 26 which is provided with perforations 27; this envelope 26 is filled with an acoustic absorbent material 28.

L'enveloppe externe 26 du noyau d'absorption 24 est réalisée en acier inoxydable, par exemple de type 316L. Les perforations 27 sont réparties de manière homogène sur toute la surface de l'enveloppe externe 26 et elles occupent entre 40 et 60 % de la surface de cette enveloppe.The outer casing 26 of the absorption core 24 is made of stainless steel, for example of the 316L type. The perforations 27 are distributed evenly over the entire surface of the outer casing 26 and they occupy between 40 and 60% of the surface of this casing.

Le matériau absorptif acoustique 28 consiste de préférence en de la laine de roche dont la densité est comprise entre 30 et 140 kg/m3, de préférence comprise entre 60 et 80 kg/m3.The acoustic absorbent material 28 preferably consists of rock wool whose density is between 30 and 140 kg/m 3 , preferably between 60 and 80 kg/m 3 .

Au moins l'extrémité amont 29 du noyau d'absorption 24 est en forme d'ogive (ou de dôme) pour limiter les perturbations du flux de fumée.At least the upstream end 29 of the absorption core 24 is in the shape of an ogive (or of a dome) to limit disturbances to the flow of smoke.

Dans le mode de réalisation illustré, l'extrémité aval 30 du noyau d'absorption 24 se présente également sous la forme d'une ogive.In the illustrated embodiment, the downstream end 30 of the absorption core 24 is also in the form of an ogive.

Ce noyau d'absorption 24 s'étend sur une partie de la longueur du tube central 5 ; de préférence il s'étend à l'intérieur du tronçon aval perforé 5b dudit tube central 5. En l'occurrence, le noyau d'absorption 24 s'étend ici sur toute ou pratiquement toute la longueur de ce tronçon aval perforé 5b, et sur toute la longueur occupée par le cylindre de noyau absorptif acoustique 14.This absorption core 24 extends over part of the length of the central tube 5; preferably it extends inside the perforated downstream section 5b of said central tube 5. In this case, the absorption core 24 here extends over the entire or practically the entire length of this perforated downstream section 5b, and over the entire length occupied by the cylinder of acoustic absorptive core 14.

Ce noyau d'absorption 24 a pour fonction et pour intérêt de rajouter du matériau absorptif pour compenser le diamètre intérieur important du dispositif d'absorption acoustique, en particulier dans le cas de tubes intérieurs ayant un diamètre supérieur ou égal à 350 mm.This absorption core 24 has the function and the advantage of adding absorptive material to compensate for the large internal diameter of the sound absorption device, in particular in the case of internal tubes having a diameter greater than or equal to 350 mm.

La figure 7 illustre encore un autre mode de réalisation d'un dispositif atténuateur de bruit 1" conforme à l'invention.The figure 7 illustrates yet another embodiment of a noise attenuator device 1" in accordance with the invention.

Ici encore, les parties structurelles communes aux modes de réalisation des figures 1 à 6 conservent les mêmes repères par mesure de simplification.Here again, the structural parts common to the embodiments of the figures 1 to 6 retain the same references for simplicity.

Ce dispositif atténuateur de bruit 1" comporte donc un tube central 5 muni de deux prolongements d'extrémité 7 et 9 et ceinturé par un tube extérieur 10.This noise attenuator device 1" therefore comprises a central tube 5 provided with two end extensions 7 and 9 and surrounded by an outer tube 10.

Ce tube extérieur 10 est assemblé avec le tube central 5 par la paroi d'extrémité amont 12 et par la paroi d'extrémité aval 13 pour définir la chambre annulaire 11.This outer tube 10 is assembled with the central tube 5 by the upstream end wall 12 and by the downstream end wall 13 to define the annular chamber 11.

Le tube central 5 comporte un tronçon amont 5a non perforé jusqu'à la zone intermédiaire 19, suivi d'un tronçon aval perforé 5b.The central tube 5 comprises a non-perforated upstream section 5a up to the intermediate zone 19, followed by a perforated downstream section 5b.

D'autre part, une couronne de matériau absorptif acoustique 14 comble la partie aval 11b de la chambre d'absorption 11.On the other hand, a ring of acoustic absorbent material 14 fills the downstream part 11b of the absorption chamber 11.

Ici une trappe de visite 31 est prévue dans le tube extérieur 10, débouchant dans la partie amont 11a en forme de cavité.Here an inspection hatch 31 is provided in the outer tube 10, opening into the upstream part 11a in the form of a cavity.

Cette trappe de visite 31 est formée d'une virole cylindrique 32 fixée sur le tube extérieur 10 (selon un axe perpendiculaire à l'axe de ce tube extérieur 10), associée à un bouchon amovible isolé 33.This inspection hatch 31 is formed of a cylindrical ferrule 32 fixed to the outer tube 10 (along an axis perpendicular to the axis of this outer tube 10), associated with an insulated removable plug 33.

Une découpe/ouverture 34 est aménagée dans la partie centrale du tube central 5 en regard de la trappe de visite 31, pour permettre l'accès à l'intérieur de ce tube central 5.A cutout/opening 34 is provided in the central part of the central tube 5 opposite the inspection hatch 31, to allow access to the interior of this central tube 5.

Une telle trappe de visite 31 permet l'entretien du dispositif, notamment lorsqu'il est placé sur des conduits desservant des chaudières à combustible solide comme le bois.Such an inspection hatch 31 allows maintenance of the device, in particular when it is placed on conduits serving boilers using solid fuel such as wood.

Ce genre de trappe de visite peut bien entendu être aménagée également dans des dispositifs atténuateurs avec noyau d'absorption, tel qu'illustré sur les figures 5 et 6.This type of inspection hatch can of course also be fitted in attenuating devices with an absorption core, as illustrated in the figures 5 and 6 .

D'une manière générale, le tronçon amont 5a du tube central 5 est de préférence dépourvu de perforations ou d'ouvertures. Cependant, une ou quelques perforations/ouvertures peuvent y être aménagées, en fonction des besoins, (comme dans le mode de réalisation de la figure 7), sans qu'elles occupent une surface de paroi importante. Cette surface de paroi perforée/ouverte du tronçon amont 5a sera en tout état de cause moins importante que celle du tronçon aval 5b.In general, the upstream section 5a of the central tube 5 preferably has no perforations or openings. However, one or a few perforations/openings can be provided, depending on the needs, (as in the embodiment of the figure 7 ), without occupying a large wall surface. This perforated/open wall surface of the upstream section 5a will in any event be smaller than that of the downstream section 5b.

Claims (12)

  1. A smoke-generating apparatus (3), such as a generator engine, a boiler or other, comprising a smoke exhaust duct (2), said smoke exhaust duct (2) comprising, in the direction of travel of the smoke, a smoke duct section (2a), a noise reduction device (1, 1', 1"), and a downstream smoke duct section (2b), said noise reduction device (1. 1', 1") comprising a central tube (5) provided, considering the direction of travel of the smoke, with an upstream extension (7) connected to the upstream smoke duct section (2a), and with a downstream extension (9) connected to the downstream smoke duct section (2b), said central tube (5) comprising perforations (20) and being surrounded by an external tube (10) to define between each other a sound absorption chamber (11), said external tube (10) being connected to said central tube (5), still considering the direction of travel of the smoke, by an upstream end wall (12), and by a downstream end wall (13), which delimit the length (L) of said sound absorption chamber (11), said sound absorption chamber being partially filled with a sound absorbing material (14) that fills its thickness between the central tube (5) and the external tube (10), over a part of its length (L),
    characterized in that said central tube (5) comprises (a) a solid upstream section (5a), devoid or almost devoid of perforations, extending from said upstream end wall (12), to an intermediate area (19) located between said upstream (12) and downstream (13) end walls, said solid upstream section (5a) being extended by (b) a downstream section (5b) provided with perforations (20), which extends from said intermediate area (19) to said downstream end wall (13) or approximately to said downstream end wall (13),
    and in that said sound absorbing material (14) is delimited (i) by an upstream end edge (14a), arranged downstream from said intermediate area (19), and (ii) by a downstream end edge (14b), arranged in said sound absorption chamber (11) near said downstream end wall (13), or against the latter,
    the space of said sound absorption chamber (11) between said upstream end wall (12) and said upstream end edge (14a) of said sound absorbing material (14), consisting of a cavity (11a), an upstream part (11a') of which surrounds said solid upstream section (5a) of said central tube (5), and a downstream part (11a") of which surrounds a perforated upstream part (5b1) of said central tube (5).
  2. The smoke-generating apparatus (3) according to claim 1, characterized in that said central tube (5) of the noise reduction device has a circular cross-section and comprises a longitudinal axis (A) on which are centred said upstream (7) and downstream (9) extensions, said sound absorption chamber (11) having a generally circular cross-section, of a constant thickness, centred to the longitudinal axis (A) of said central tube (5).
  3. The smoke-generating apparatus (3) according to any one of claims 1 or 2, characterized in that the sound absorbing material (14) of the sound absorbing material consists of rock wool whose density is between 30 et 140 kg/m3, preferably between 60 and 120 kg/m3,
  4. The smoke-generating apparatus (3) according to any one of claims 1 to 3, characterized in that the diameter of the central tube (5) of the noise reduction device is between 130 and 600 mm, in that the thickness of the sound absorption chamber (11) is between 100 and 150 mm, and in that the length of said sound absorption chamber (11) is between 700 and 1000 mm.
  5. The smoke-generating apparatus (3) according to any one of claims 1 to 4, characterized in that said sound absorbing material (14) extends between 1/3 and 2/3 of the length (L) of the sound absorption chamber (11), and in that the perforated upstream part (5b1) of said central tube (5), which is surrounded by said downward cavity part (11a"), extends between 1/6 and 1/2 of the length of said cavity (11a).
  6. The smoke-generating apparatus (3) according to any one of claims 1 to 5, characterized in that the perforations (20) of the downstream section (5b) of the central tube (5) of the noise reduction device have a diameter between 5 and 20 mm and occupy from 15 to 70 % of the wall surface area of said downstream section of central tube (5b).
  7. The smoke-generating apparatus (3) according to any one of claims 1 to 6, characterized in that the external tube (10) of the noise reduction device is removably fastened to cylindrical crowns (15, 16) that extend said upstream (12) and downstream (13) end walls, by means of clamp collars (17, 18).
  8. The smoke-generating apparatus (3) according to any one of claims 1 to 7, characterized in that the noise reduction device comprises an internal absorption core (24) of generally cylindrical shape, mounted coaxially to said central tube (5), inside the latter, said core (24) having a diameter lower than the diameter of said central tube (5), comprising an upstream end, directed towards said upstream extension (7), having the shape of an ogive (29), and having an external envelope (26) provided with perforations (27) and filled with a sound absorbing material (28).
  9. The smoke-generating apparatus (3) according to any one of claims 1 to 8, characterized in that the noise reduction device comprises an inspection door (31) arranged in the external tube (10), associated with a removable plug (33).
  10. The smoke-generating apparatus (3) according to any one of claims 1 to 9, characterized in that said cavity (11a) of said sound absorption chamber (11) of the noise reduction device is delimited, on one side, by the upstream end edge (14a) of the sound absorbing material (14).
  11. The smoke-generating apparatus (3) according to any one of claims 1 to 10, characterized in that said upstream extension (7) of the central tube (5) of said noise reduction device has the shape of a male end-piece adapted to cooperate with a female end-piece of an upstream smoke duct section (2a), and in that said downstream extension (9) of the central tube (5) of the noise reduction device has the shape of a female end-piece adapted to cooperate with a male end-piece of a downstream smoke duct section (2b).
  12. The smoke-generating apparatus (3) according to any one of claims 1 to 11, characterized in that said downstream extension (9) of the central tube (5) of the noise reduction device comprises an internal tube section (9a1), which extends towards the inside, and receives the downstream end (8) of said central tube (5) by fitting mounting, said internal tube section (9a1) being provided with perforations (9a2).
EP20183656.6A 2019-07-03 2020-07-02 Smoke-producing device with silencer in a smoke evacuation conduit Active EP3760924B1 (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
FR1907419A FR3098280B1 (en) 2019-07-03 2019-07-03 Noise attenuating device for a smoke exhaust duct fitted to a smoke-producing device

Publications (2)

Publication Number Publication Date
EP3760924A1 EP3760924A1 (en) 2021-01-06
EP3760924B1 true EP3760924B1 (en) 2022-10-12

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Application Number Title Priority Date Filing Date
EP20183656.6A Active EP3760924B1 (en) 2019-07-03 2020-07-02 Smoke-producing device with silencer in a smoke evacuation conduit

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EP (1) EP3760924B1 (en)
FR (1) FR3098280B1 (en)

Family Cites Families (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB403651A (en) * 1931-06-20 1933-12-20 Burgess Lab Inc C F Silencer for gaseous currents
US3757892A (en) * 1972-04-03 1973-09-11 Skyway Machine Inc Exhaust unit for combustion engine
JP5450499B2 (en) * 2011-04-18 2014-03-26 本田技研工業株式会社 Silencer
FR3011617B1 (en) 2013-10-03 2015-10-23 Poujoulat NOISE ATTENUATING DEVICE FOR A SMOKE EXHAUST DUCT EQUIPPING A BOILER

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FR3098280B1 (en) 2021-07-30
EP3760924A1 (en) 2021-01-06

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