EP0165145B1 - Fan silencer which can be regenerated in situ, for use in ventilation plants fed with dusty air, and process to regenerate this silencer in situ - Google Patents
Fan silencer which can be regenerated in situ, for use in ventilation plants fed with dusty air, and process to regenerate this silencer in situ Download PDFInfo
- Publication number
- EP0165145B1 EP0165145B1 EP85400978A EP85400978A EP0165145B1 EP 0165145 B1 EP0165145 B1 EP 0165145B1 EP 85400978 A EP85400978 A EP 85400978A EP 85400978 A EP85400978 A EP 85400978A EP 0165145 B1 EP0165145 B1 EP 0165145B1
- Authority
- EP
- European Patent Office
- Prior art keywords
- sound
- layer
- silencer
- compressed air
- retaining wall
- 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
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- 230000003584 silencer Effects 0.000 title claims abstract description 46
- 238000011065 in-situ storage Methods 0.000 title claims abstract description 13
- 238000009423 ventilation Methods 0.000 title claims abstract description 10
- 238000000034 method Methods 0.000 title claims description 10
- 239000012530 fluid Substances 0.000 claims abstract description 22
- 239000000463 material Substances 0.000 claims abstract description 17
- 239000000126 substance Substances 0.000 claims abstract description 11
- 239000002184 metal Substances 0.000 claims abstract description 10
- 239000011810 insulating material Substances 0.000 claims abstract description 7
- 239000011358 absorbing material Substances 0.000 claims description 22
- 230000008929 regeneration Effects 0.000 claims description 15
- 238000011069 regeneration method Methods 0.000 claims description 15
- 239000004744 fabric Substances 0.000 claims description 11
- 238000009434 installation Methods 0.000 claims description 5
- 238000005192 partition Methods 0.000 claims description 4
- 239000003595 mist Substances 0.000 claims description 3
- 238000002347 injection Methods 0.000 claims 1
- 239000007924 injection Substances 0.000 claims 1
- 238000004140 cleaning Methods 0.000 description 15
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 7
- 239000003599 detergent Substances 0.000 description 5
- 239000000428 dust Substances 0.000 description 5
- 238000001035 drying Methods 0.000 description 4
- 238000005259 measurement Methods 0.000 description 3
- 239000007787 solid Substances 0.000 description 3
- 229920002994 synthetic fiber Polymers 0.000 description 3
- 239000003245 coal Substances 0.000 description 2
- 230000000052 comparative effect Effects 0.000 description 2
- 239000006260 foam Substances 0.000 description 2
- 239000011491 glass wool Substances 0.000 description 2
- 239000011490 mineral wool Substances 0.000 description 2
- 125000006850 spacer group Chemical group 0.000 description 2
- 239000012209 synthetic fiber Substances 0.000 description 2
- 239000004952 Polyamide Substances 0.000 description 1
- 239000004698 Polyethylene Substances 0.000 description 1
- 235000021028 berry Nutrition 0.000 description 1
- 239000004927 clay Substances 0.000 description 1
- 238000005056 compaction Methods 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 238000010586 diagram Methods 0.000 description 1
- 238000010410 dusting Methods 0.000 description 1
- 230000005611 electricity Effects 0.000 description 1
- 230000007613 environmental effect Effects 0.000 description 1
- 238000005187 foaming Methods 0.000 description 1
- 239000003365 glass fiber Substances 0.000 description 1
- 230000009931 harmful effect Effects 0.000 description 1
- 238000009413 insulation Methods 0.000 description 1
- 238000005065 mining Methods 0.000 description 1
- 229920002647 polyamide Polymers 0.000 description 1
- -1 polyethylene Polymers 0.000 description 1
- 229920000573 polyethylene Polymers 0.000 description 1
- 239000011148 porous material Substances 0.000 description 1
- 230000000750 progressive effect Effects 0.000 description 1
- 230000001172 regenerating effect Effects 0.000 description 1
- 230000002787 reinforcement Effects 0.000 description 1
- 230000000284 resting effect Effects 0.000 description 1
- 238000000926 separation method Methods 0.000 description 1
- 239000010802 sludge Substances 0.000 description 1
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- 230000003068 static effect Effects 0.000 description 1
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Images
Classifications
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M35/00—Combustion-air cleaners, air intakes, intake silencers, or induction systems specially adapted for, or arranged on, internal-combustion engines
- F02M35/12—Intake silencers ; Sound modulation, transmission or amplification
- F02M35/1272—Intake silencers ; Sound modulation, transmission or amplification using absorbing, damping, insulating or reflecting materials, e.g. porous foams, fibres, rubbers, fabrics, coatings or membranes
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- E—FIXED CONSTRUCTIONS
- E21—EARTH OR ROCK DRILLING; MINING
- E21F—SAFETY DEVICES, TRANSPORT, FILLING-UP, RESCUE, VENTILATION, OR DRAINING IN OR OF MINES OR TUNNELS
- E21F1/00—Ventilation of mines or tunnels; Distribution of ventilating currents
- E21F1/08—Ventilation arrangements in connection with air ducts, e.g. arrangements for mounting ventilators
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02M—SUPPLYING COMBUSTION ENGINES IN GENERAL WITH COMBUSTIBLE MIXTURES OR CONSTITUENTS THEREOF
- F02M35/00—Combustion-air cleaners, air intakes, intake silencers, or induction systems specially adapted for, or arranged on, internal-combustion engines
- F02M35/12—Intake silencers ; Sound modulation, transmission or amplification
- F02M35/1283—Manufacturing or assembly; Connectors; Fixations
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F24—HEATING; RANGES; VENTILATING
- F24F—AIR-CONDITIONING; AIR-HUMIDIFICATION; VENTILATION; USE OF AIR CURRENTS FOR SCREENING
- F24F13/00—Details common to, or for air-conditioning, air-humidification, ventilation or use of air currents for screening
- F24F13/24—Means for preventing or suppressing noise
Definitions
- the invention relates to sound attenuation silencers which are associated with fans supplied with dusty air; it also relates to a process for regenerating these silencers.
- These silencers are generally cylindrical devices having an outer sheet metal wall against which is held an annular layer of a material with high soundproofing power, resistant to heat, humidity and compaction.
- the sound-absorbing substance used can be rock wool, glass wool, open cell foam, clay foam, etc.
- the internal wall of the silencer in contact with the air flow to be soundproofed consists of a perforated sheet, the internal face of this sheet holding the layer of soundproofing substance in place.
- a central bulb analogous to a nucleus with a domed head of generally cylindrical or frustoconical shape. This bulb ensures better continuity of air flow and promotes the supply of the fan wheel. This bulb also contains soundproofing material held in place by a perforated sheet envelope. It also participates in noise reduction.
- the main purpose of the invention is to achieve in situ regenerable silencers, if desired while the fans are running, which can be easily regenerated as often as needed to keep the noise level below of a fixed threshold.
- a silencer for a fan composed of a tubular section containing a central inner core.
- This inner core is constituted by a cylindrical volume of insulating material phonetically contained in a metallic envelope composed of assembled sheets.
- the tubular section has a perimeter wall constituted by a thickness of material, phonetically insulating, covered with an external metallic envelope composed of assembled sheets.
- the sheets of the outer wall and the inner core are independent of the insulating material; they are fixed to a general structure and assembled together using bolts, so that it is necessary, laboriously, to dismantle the bolts and remove the sheets before accessing the insulating material and removing it entirely to replace it.
- FR-A-2 205 625 also describes an acoustic insulation device for a ventilation fan used in mining operations.
- an in situ regenerable silencer intended to be associated with a fan in a ventilation installation supplied with dusty air, comprising an outer casing made of solid material, a retaining wall located under this casing outer, a layer of sound-absorbing material with an outer face, contained by said retaining wall, an internal perforated wall supporting said layer of sound-absorbing material
- the retaining wall has large passage openings while the outer casing is in solid sheet metal and it is separated radially from the retaining wall by an interval revealing a closed volume, the latter being either connected to an end piece external to the silencer for connection to a supply line for a cleaning fluid, or occupied at least partially by a layer of insulating material lining the inner face of said outer envelope, this co mlois opening panels hinged using hinges on said retaining wall.
- the perforated internal wall which supports the soundproofing material comprises a cage constituted by perforated tubes and connected to a means of connection to a network of pressurized air.
- the cleaning fluid is preferably constituted by water added with a detergent.
- the regeneration of the layer of the sound absorbing material of the silencer is done in the following manner.
- compressed air and the cleaning fluid are injected simultaneously into the annular volume comprised between the outer casing of the silencer and the layer of sound-absorbing material without stopping the fan.
- the cleaning fluid mist passes through the layer of sound-absorbing material and entrains the dust into the air flow sucked in or blown out by the fan. Then one can either stop the introduction of cleaning fluid alone and then continue the introduction of air so as to dry the layer of sound-absorbing material, or simultaneously stop the introduction of cleaning fluid and compressed air.
- the wet dust obtained during regeneration is not a nuisance.
- the cleaning fluid is preferably prepared beforehand in a bottle of adequate capacity and resistance to pressure connected on the one hand to the annular volume located between the outer envelope and the layer of sound-absorbing material and on the other hand to a source of compressed air, a cut-off valve being mounted between the cylinder and the source of compressed air. Opening the valve sprays the cleaning fluid as a mist on the layer of sound-absorbing material. When all the cleaning fluid has been expelled from the bottle, drying can be ensured by continuing the introduction of compressed air.
- a silencer it is preferable but not necessarily necessary to stop the fan before cleaning the layer of sound-absorbing material.
- a removable panel is moved and a pressurized water jet is sprayed onto the soundproofing material with the addition of a detergent. This is done panel by panel.
- the internal face of the layer of sound-absorbing material is supported by a rot-proof fabric of artificial fibers (polyamide, polyethylene) or non-combustible (glass fibers) with loose texture having more than 50% of empty surface.
- This fabric has the advantage of not catching dust which facilitates its regeneration.
- this fabric has a higher acoustic efficiency than a perforated sheet.
- This fabric is itself supported by a sufficiently rigid mesh but with very loose mesh, for example in galvanized or plasticized wire. It can also rest on a metal cage.
- This cage is formed of widely spaced metal bars oriented along the axis of the silencer. It has the advantage of protecting against the appearance of dangerous static electricity charges.
- This metal cage is preferably constituted by tubes capable of being connected to a source of compressed air by means of a flexible hose and an electropneumatic valve; they are arranged so that, after connection, they play the role of ejectors whose jets are directed towards the blades of the fan. In addition to rapid drying of the soundproofing material after it has been washed, this assembly allows useful automatic emergency ventilation in the event of an accidental interruption of the electric current.
- the external retaining wall of the layer of sound-absorbing material may consist of a metal cage or a sufficiently rigid mesh with loose mesh or holding in place a fabric with a loose texture.
- the layer of sound-absorbing material can be formed in a known manner by rock wool, glass wool or any other porous material.
- annular volume between the external sheet of the silencer and the layer of soundproofing material may be divided by partitions so as to form several boxes.
- These boxes can be connected successively to the compressed air source. These boxes can be longitudinal or transverse.
- the silencers When the silencers are provided with a central bulb, consisting of a soundproofing material held in place by an envelope, there is provided inside this layer of soundproofing material a central volume limited by an internal wall and connected to a connection end piece. a cleaning fluid inlet pipe.
- the regeneration of the bulb is carried out in the same way as that of the annular layer of sound-absorbing material.
- the regeneration of the bulb and the annular layer can be carried out simultaneously or independently.
- the outer wall of the bulb is as in the case of the outer cylindrical wall of the annular layer of the sound absorbing material constituted by a mesh or a metal cage holding in place a fabric with a loose texture.
- An in situ regenerable silencer comprises an outer casing 1 made of solid sheet which is separated, that is to say without definitive connection, from a layer of soundproofing material 2 which it contains.
- an interval in the radial direction which causes an annular volume 3 to appear between the outer casing 1 and the sound-absorbing material 2.
- This annular volume 3 is closed at its opposite ends in the axial direction and it is connected to a nozzle. compressed air and water containing detergent.
- the soundproofing material 2 is supported on its internal face by a fabric 5 of loose-textured synthetic fibers which is itself supported by a rigid cage made up of tubes 6; the latter are perforated in their interior part to the silencer and, outside of the latter, they are connected to a flexible pipe 7 terminating in an electropneumatic valve 8 which is part of a compressed air distribution network.
- the soundproofing material 2 is supported on its external face 9 by a fabric of synthetic fibers with a loose texture, preferably identical to the fabric 5 of the internal face, which rests on a semi-rigid metallic mesh with large meshes, made of plasticized wire of preference.
- This external retaining wall 10, not shown in detail, is spaced from the external envelope 1 by the annular volume 3.
- FIG. 3 shows in cross section a silencer similar to that of Figures 1, 2 where the same references designate the same parts.
- This example is that of a first aspect of the invention according to which the outer casing 1 ′ in solid sheet is made up of removable panels.
- a longitudinal rigid frame 11 carries hinges 12 by means of which panels 13 are pivotally mounted by one of their longitudinal edges; the opposite longitudinal edge makes it possible to fix each panel 13 to the frame 11, in the closed position.
- the outer envelope 1 ′ is separated from the layer 2 of sound-absorbing material; however the annular volume 3 of Figures 1 and 2 is no longer necessary. It is therefore possible to fill the inner face of the panels 13 with a layer 14 of insulating material.
- This FIG. 3 also shows that the rigid reinforcement 11 is used to hold the outer wall 10 of the layer of soundproofing material 2 in position using spacers 15.
- the in situ regeneration consists with the silencer of FIGS. 1 and 2 in connecting the end piece 4 and in opening the valve 8 for cleaning and drying as explained above.
- the silencer of Figure 3 we can either stop the fan, open all the panels 13 and send from the outside using a nozzle 16 a jet of pressurized water added with a detergent, which runs in one minute per m 3 of soundproofing material 2 cleaned. The water descends through the mass of the material 2. It is advisable to adhere to the lower part thereof a waterproof strip 17; by giving the entire installation a slight longitudinal slope, the washing water is collected, channeled and evacuated without difficulty.
- the silencer of the invention differs in its construction from conventional silencers, it was useful to check the quality of sound reduction.
- Lp 1, Lp 2, Lp 3 are the acoustic levels
- Lp is the weighted surface sound pressure level
- Lw is the sound power level according to standard NFS 31-021.
- the acoustic attenuation coefficient is 22.1 dBA and for a conventional silencer it is only 18.4.
- annular volume 3 it is possible to partition the annular volume 3 by transverse and longitudinal partitions to reveal boxes which can be connected all together or separately to the inlet pipe for the cleaning fluid.
- these boxes can correspond to removable panels of the external envelope 1.
- the internal wall and the external wall can be produced in many ways; but it is preferable in many circumstances to provide a support with a loose texture having more than 50% of empty surface.
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Mining & Mineral Resources (AREA)
- Life Sciences & Earth Sciences (AREA)
- General Life Sciences & Earth Sciences (AREA)
- Geochemistry & Mineralogy (AREA)
- Geology (AREA)
- Manufacturing & Machinery (AREA)
- Structures Of Non-Positive Displacement Pumps (AREA)
- Exhaust Silencers (AREA)
Abstract
Description
L'invention concerne les silencieux d'atténuation acoustique qui sont associés aux ventilateurs alimentés en air empoussiéré ; elle se rapporte aussi à un procédé de régénération de ces silencieux.The invention relates to sound attenuation silencers which are associated with fans supplied with dusty air; it also relates to a process for regenerating these silencers.
De nombreuses installations d'aérage sont utilisées dans les mines, en particulier les mines de charbons. Ces installations comportent fréquemment des ventilateurs électriques d'aérage dont les puissances atteignent parfois des centaines de kWh. Afin de limiter à un niveau acceptable la puissance acoustique rayonnée dans l'environnement, il est connu d'équiper ces ventilateurs de silencieux placés sur leur aspiration et/ou leur refoulement, destinés à réduire la puissance acoustique rayonnée par l'orifice d'aspiration et/ou de refoulement et à diminuer ainsi l'effet nuisible du bruit de l'environnement.Many ventilation systems are used in mines, in particular coal mines. These installations frequently include electric ventilation fans whose powers sometimes reach hundreds of kWh. In order to limit the sound power radiated into the environment to an acceptable level, it is known to equip these fans with silencers placed on their suction and / or discharge, intended to reduce the sound power radiated by the suction orifice and / or backflow and thereby reduce the harmful effect of environmental noise.
Ces silencieux sont des appareils généralement cylindriques comportant une paroi extérieure en tôle contre laquelle est maintenue une couche annulaire d'un matériau à haut pouvoir insonorisant, résistant à la chaleur, à l'humidité et au tassement. La substance insonorisante utilisée peut être de la laine de roche, de la laine de verre, une mousse à cellules ouvertes, une mousse d'argile, etc.These silencers are generally cylindrical devices having an outer sheet metal wall against which is held an annular layer of a material with high soundproofing power, resistant to heat, humidity and compaction. The sound-absorbing substance used can be rock wool, glass wool, open cell foam, clay foam, etc.
En général la paroi interne du silencieux en contact avec le flux d'air à insonoriser est constituée d'une tôle perforée, la face interne de cette tôle maintenant en place la couche de substance insonorisante.In general, the internal wall of the silencer in contact with the air flow to be soundproofed consists of a perforated sheet, the internal face of this sheet holding the layer of soundproofing substance in place.
A l'intérieur du silencieux peut se trouver un bulbe central analogue à un noyau à tête bombée de forme générale cylindrique ou tronconique. Ce bulbe assure une meilleure continuité de l'écoulement de l'air et favorise l'alimentation de la roue du ventilateur. Ce bulbe contient également un matériau insonorisant maintenu en place par une enveloppe en tôle perforée. Il participe aussi à l'atténuation du bruit.Inside the silencer can be found a central bulb analogous to a nucleus with a domed head of generally cylindrical or frustoconical shape. This bulb ensures better continuity of air flow and promotes the supply of the fan wheel. This bulb also contains soundproofing material held in place by a perforated sheet envelope. It also participates in noise reduction.
Un des problèmes posés par l'utilisation des silencieux actuellement fabriqués est qu'ils perdent une part importante de leur efficacité après une plus ou moins longue durée de service en atmosphère empoussiérée. En effet, les poussières transportées par le flux d'air se déposent sur la face interne des appareils et forment une pellicule qui obture progressivement les perforations de la tôle. Par conséquent, la poussière acoustique rayonnée augmente progressivement pour tendre vers celle qui serait rayonnée par le ventilateur en l'absence de silencieux.One of the problems posed by the use of currently manufactured silencers is that they lose a significant part of their effectiveness after a more or less long service life in a dusty atmosphere. In fact, the dust transported by the air flow is deposited on the internal face of the devices and forms a film which progressively closes the perforations in the sheet. Consequently, the radiated acoustic dust gradually increases to tend towards that which would be radiated by the fan in the absence of a silencer.
Pour ne pas dépasser le niveau sonore admissible, il devient alors nécessaire de démonter tout ou partie de ces silencieux afin de remplacer les éléments empoussiérés par des éléments qui ont été nettoyés et dépoussiérés. Cette opération doit être renouvelée fréquemment et elle entraîne un arrêt prolongé du ventilateur. Elle nécessite par ailleurs le transport en atelier des éléments empoussiérés, leur régénération se faisant soit par un secouage violent sur un châssis vibrant, soit par un trempage dans un bain détergent suivi d'un séchage.In order not to exceed the admissible sound level, it then becomes necessary to dismantle all or part of these silencers in order to replace the dusty elements by elements that have been cleaned and dusted. This must be repeated frequently and will cause the fan to stop for a long time. It also requires transporting the dusty elements to the workshop, their regeneration being carried out either by violent shaking on a vibrating frame, or by soaking in a detergent bath followed by drying.
On a proposé de remédier au problème de l'empoussiérage des silencieux en montant à l'entrée du silencieux d'aspiration un élément filtrant sous forme de panneaux fixés à une armature ou sous forme d'un élément filtrant interchangeable, en particulier plié en accordéon, reposant sur une armature fixe. Mais dans les milieux très empoussiérés comme les mines de charbon, ces éléments filtrants sont colmatés en à peine plus d'une heure.It has been proposed to remedy the problem of the dusting of the silencers by mounting at the inlet of the suction silencer a filter element in the form of panels fixed to a frame or in the form of an interchangeable filter element, in particular folded in accordion , resting on a fixed frame. But in very dusty environments like coal mines, these filter elements are clogged in just over an hour.
L'invention a pour but principal de parvenir à des silencieux régénérables in situ, si on le souhaite pendant que les ventilateurs sont en marche, qui peuvent être régénérés facilement aussi souvent que le besoin s'en fait sentir pour maintenir la nuisance acoustique en dessous d'un seuil fixé.The main purpose of the invention is to achieve in situ regenerable silencers, if desired while the fans are running, which can be easily regenerated as often as needed to keep the noise level below of a fixed threshold.
Dans le document US-A-3 949 830, il est déjà décrit un silencieux pour ventilateur composé d'un tronçon tubulaire contenant un noyau intérieur central. Ce noyau intérieur est constitué par un volume cylindrique de matière isolante phonétiquement contenu dans une enveloppe métallique composée de tôles assemblées. Le tronçon tubulaire a une paroi périmétrique constituée par une épaisseur de matière, isolante phonétiquement, couverte d'une enveloppe métallique extérieure composée de tôles assemblées. Les tôles de la paroi extérieure et du noyau intérieur sont indépendantes de la matière isolante ; elles sont fixées à une structure générale et assemblées entre elles à l'aide de boulons, de sorte qu'il faut, laborieusement, démonter les boulons et retirer les tôles avant d'accéder à la matière isolante et de retirer entièrement celle-ci pour la remplacer.In document US-A-3,949,830, there is already described a silencer for a fan composed of a tubular section containing a central inner core. This inner core is constituted by a cylindrical volume of insulating material phonetically contained in a metallic envelope composed of assembled sheets. The tubular section has a perimeter wall constituted by a thickness of material, phonetically insulating, covered with an external metallic envelope composed of assembled sheets. The sheets of the outer wall and the inner core are independent of the insulating material; they are fixed to a general structure and assembled together using bolts, so that it is necessary, laboriously, to dismantle the bolts and remove the sheets before accessing the insulating material and removing it entirely to replace it.
Le FR-A-2 205 625 décrit aussi un dispositif d'isolation acoustique pour ventilateur d'aérage utilisé dans les exploitations minières.FR-A-2 205 625 also describes an acoustic insulation device for a ventilation fan used in mining operations.
A la différence de ce qui est rappelé ci-dessus dans un silencieux régénérable in situ destiné à être associé à un ventilateur dans une installation de ventilation alimentée en air empoussiéré, comprenant une enveloppe extérieure en matière pleine, une paroi de maintien située sous cette enveloppe extérieure, une couche de matériau insonorisant à face extérieure, contenue par ladite paroi de maintien, une paroi interne perforée soutenant ladite couche de matériau insonorisant, selon l'invention la paroi de maintien a de larges ouvertures de passage cependant que l'enveloppe extérieure est en tôle pleine et elle est séparée radialement de la paroi de maintien par un intervalle faisant apparaître un volume fermé, ce dernier étant soit relié à un embout extérieur au silencieux pour un raccordement à une conduite d'arrivée d'un fluide de nettoyage, soit occupé au moins partiellement par une couche de matériau isolant garnissant la face intérieure de ladite enveloppe extérieure, celle-ci comprenant des panneaux ouvrants articulés à l'aide de charnières sur ladite paroi de maintien.Unlike what is mentioned above in an in situ regenerable silencer intended to be associated with a fan in a ventilation installation supplied with dusty air, comprising an outer casing made of solid material, a retaining wall located under this casing outer, a layer of sound-absorbing material with an outer face, contained by said retaining wall, an internal perforated wall supporting said layer of sound-absorbing material, according to the invention, the retaining wall has large passage openings while the outer casing is in solid sheet metal and it is separated radially from the retaining wall by an interval revealing a closed volume, the latter being either connected to an end piece external to the silencer for connection to a supply line for a cleaning fluid, or occupied at least partially by a layer of insulating material lining the inner face of said outer envelope, this co mprenant opening panels hinged using hinges on said retaining wall.
De préférence, dans les deux cas la paroi interne perforée qui soutient le matériau insonorisant comprend une cage constituée par des tubes perforés et reliés à un moyen de raccordement à un réseau d'air sous pression.Preferably, in both cases the perforated internal wall which supports the soundproofing material comprises a cage constituted by perforated tubes and connected to a means of connection to a network of pressurized air.
Le fluide de nettoyage est de préférence constitué par de l'eau additionnée d'un détergent.The cleaning fluid is preferably constituted by water added with a detergent.
Selon le procédé de l'invention, la régénération de la couche du matériau insonorisant du silencieux se fait de la façon suivante. Avec un silencieux conforme au second aspect de l'invention, on injecte simultanément dans le volume annulaire compris entre l'enveloppe extérieure du silencieux et la couche de matériau insonorisant de l'air comprimé et du fluide de nettoyage sans arrêter le ventilateur. Le brouillard de fluide de nettoyage traverse la couche de matériau insonorisant et entraîne les poussières dans le courant d'air aspiré ou refoulé par le ventilateur. Ensuite on peut soit arrêter l'introduction de fluide nettoyant seul et poursuivre alors l'introduction d'air de façon à sécher la couche de matériau insonorisant, soit arrêter simultanément l'introduction de fluide nettoyant et d'air comprimé. Les poussières humides obtenues au cours de la régénération ne sont pas gênantes. En effet elles sont centrifugées pendant la traversée du ou des rotors du ventilateur et ainsi détournées dans le conduit d'aérage en dehors de la position axiale occupée par le moteur électrique. Elles se déposent ensuite sous forme de boues à une distance plus ou moins longue fonction des caractéristiques de la ventilation et du pouvoir moussant du fluide nettoyant.According to the method of the invention, the regeneration of the layer of the sound absorbing material of the silencer is done in the following manner. With a silencer according to the second aspect of the invention, compressed air and the cleaning fluid are injected simultaneously into the annular volume comprised between the outer casing of the silencer and the layer of sound-absorbing material without stopping the fan. The cleaning fluid mist passes through the layer of sound-absorbing material and entrains the dust into the air flow sucked in or blown out by the fan. Then one can either stop the introduction of cleaning fluid alone and then continue the introduction of air so as to dry the layer of sound-absorbing material, or simultaneously stop the introduction of cleaning fluid and compressed air. The wet dust obtained during regeneration is not a nuisance. In fact, they are centrifuged during the passage of the fan rotor (s) and thus diverted into the ventilation duct outside the axial position occupied by the electric motor. They are then deposited in the form of sludge at a more or less long distance depending on the characteristics of the ventilation and the foaming power of the cleaning fluid.
Le fluide de nettoyage est de préférence préparé préalablement dans une bouteille de capacité et de résistance à la pression adéquates reliée d'une part au volume annulaire situé entre l'enveloppe extérieure et la couche de matériau insonorisant et d'autre part à une source d'air comprimé, une vanne de coupure étant montée entre la bouteille et la source d'air comprimé. L'ouverture de la vanne provoque la pulvérisation du fluide de nettoyage sous forme de brouillard sur la couche de matériau insonorisant. Lorsque la totalité du fluide de nettoyage a été chassée de la bouteille, le séchage peut être assuré en poursuivant l'introduction d'air comprimé.The cleaning fluid is preferably prepared beforehand in a bottle of adequate capacity and resistance to pressure connected on the one hand to the annular volume located between the outer envelope and the layer of sound-absorbing material and on the other hand to a source of compressed air, a cut-off valve being mounted between the cylinder and the source of compressed air. Opening the valve sprays the cleaning fluid as a mist on the layer of sound-absorbing material. When all the cleaning fluid has been expelled from the bottle, drying can be ensured by continuing the introduction of compressed air.
Avec un silencieux conforme au premier aspect de l'invention, il est préférable mais pas forcément nécessaire d'arrêter le ventilateur avant de nettoyer la couche de matériau insonorisant. On déplace un panneau amovible et on projette sur le matériau insonorisant un jet d'eau sous pression avec adjonction d'un détergent. On procède ainsi panneau par panneau.With a silencer according to the first aspect of the invention, it is preferable but not necessarily necessary to stop the fan before cleaning the layer of sound-absorbing material. A removable panel is moved and a pressurized water jet is sprayed onto the soundproofing material with the addition of a detergent. This is done panel by panel.
Selon un mode de réalisation préféré de l'invention, la face interne de la couche de matériau insonorisant est soutenue par un tissu imputrescible en fibres artificielles (polyamide, polyéthylène) ou incombustible (fibres de verre) à texture lâche présentant plus de 50% de surface vide. Ce tissu a l'avantage de ne pas accrocher les poussières ce qui facilite sa régénération. D'autre part, ce tissu a une efficacité plus élevée du point de vue acoustique qu'une tôle perforée.According to a preferred embodiment of the invention, the internal face of the layer of sound-absorbing material is supported by a rot-proof fabric of artificial fibers (polyamide, polyethylene) or non-combustible (glass fibers) with loose texture having more than 50% of empty surface. This fabric has the advantage of not catching dust which facilitates its regeneration. On the other hand, this fabric has a higher acoustic efficiency than a perforated sheet.
Ce tissu est lui-même soutenu par un grillage suffisamment rigide mais à mailles très lâches par exemple en fil galvanisé ou plastifié. Il peut également reposer sur une cage métallique. Cette cage est formée de barreaux métalliques largement espacés orientés suivant l'axe du silencieux. Elle a l'avantage de protéger contre l'apparition de charges dangereuses d'électricité statique. Cette cage métallique est de préférence constituée par des tubes susceptibles d'être raccordés à une source d'air comprimé par l'intermédiaire d'un flexible et d'une vanne électropneumatique ; ils sont disposés pour que, après raccordement, ils jouent le rôle d'éjecteurs dont les jets sont dirigés vers les pales du ventilateur. En plus d'un séchage rapide du mtériau insonorisant après son lavage, ce montage permet une utile ventilation automatique de secours en cas de coupure accidentelle ou non du courant électrique.This fabric is itself supported by a sufficiently rigid mesh but with very loose mesh, for example in galvanized or plasticized wire. It can also rest on a metal cage. This cage is formed of widely spaced metal bars oriented along the axis of the silencer. It has the advantage of protecting against the appearance of dangerous static electricity charges. This metal cage is preferably constituted by tubes capable of being connected to a source of compressed air by means of a flexible hose and an electropneumatic valve; they are arranged so that, after connection, they play the role of ejectors whose jets are directed towards the blades of the fan. In addition to rapid drying of the soundproofing material after it has been washed, this assembly allows useful automatic emergency ventilation in the event of an accidental interruption of the electric current.
La paroi de maintien externe de la couche de matériau insonorisant peut être constituée par une cage métallique ou un grillage suffisamment rigide à mailles lâches ou maintenant en place un tissu à texture lâche.The external retaining wall of the layer of sound-absorbing material may consist of a metal cage or a sufficiently rigid mesh with loose mesh or holding in place a fabric with a loose texture.
La couche de matériau insonorisant peut être constituée de manière connue par de la laine de roche, de la laine de verre ou tout autre matériau poreux.The layer of sound-absorbing material can be formed in a known manner by rock wool, glass wool or any other porous material.
Selon la dimension du silencieux et la puissance de la source d'air comprimé disponible il peut être avantageux de diviser le volume annulaire compris entre la tôle extérieure du silencieux et la couche de matériau insonorisant en éléments annulaires par des cloisons de façon à former plusieurs caissons pouvant être reliés successivement à la source d'air comprimé. Ces caissons peuvent être longitudinaux ou transversaux.Depending on the size of the silencer and the power of the source of compressed air available, it may be advantageous to divide the annular volume between the external sheet of the silencer and the layer of soundproofing material into annular elements by partitions so as to form several boxes. can be connected successively to the compressed air source. These boxes can be longitudinal or transverse.
On peut ainsi régénérer par fractions la couche de substance insonorisante, de même qu'en enlevant ou en ouvrant successivement les panneaux amovibles de l'enveloppe extérieure.It is thus possible to regenerate by fractions the layer of sound-absorbing substance, as well as by removing or opening successively the removable panels of the outer envelope.
Lorsque les silencieux sont munis d'un bulbe central, constitué par un matériau insonorisant maintenu en place par une enveloppe, on prévoit à l'intérieur de cette couche de matériau insonorisant un volume central limité par une paroi interne et relié à un embout de raccordement d'une conduite d'arrivée d'un fluide de nettoyage. La régénération du bulbe s'effectue de la même façon que celle de la couche annulaire de matériau insonorisant. La régénération du bulbe et de la couche annulaire peuvent être effectuées simultanément ou indépendamment. La paroi externe du bulbe est comme dans le cas de la paroi cylindrique externe de la couche annulaire du matériau insonorisant constituée par un grillage ou une cage métallique maintenant en place un tissu à texture lâche.When the silencers are provided with a central bulb, consisting of a soundproofing material held in place by an envelope, there is provided inside this layer of soundproofing material a central volume limited by an internal wall and connected to a connection end piece. a cleaning fluid inlet pipe. The regeneration of the bulb is carried out in the same way as that of the annular layer of sound-absorbing material. The regeneration of the bulb and the annular layer can be carried out simultaneously or independently. The outer wall of the bulb is as in the case of the outer cylindrical wall of the annular layer of the sound absorbing material constituted by a mesh or a metal cage holding in place a fabric with a loose texture.
On donnera maintenant une description de deux exemples de réalisation de l'invention en se reportant aux dessins annexés dans lesquels :
- - la figure 1 est une vue en coupe transversale d'un silencieux conforme au second aspect de l'invention et régénérable in situ ;
- - la figure 2 est une représentation schématique de côté du même silencieux ;
- - la figure 3 est une vue en coupe transversale d'un silencieux conforme au premier aspect de l'invention et régénérable in.situ ;
- - les figures 4 et 5 sont des schémas montrant l'emplacement de points de mesure au cours d'essais comparatifs d'atténuation acoustique.
- - Figure 1 is a cross-sectional view of a silencer according to the second aspect of the invention and regenerable in situ;
- - Figure 2 is a schematic side view of the same silencer;
- - Figure 3 is a cross-sectional view of a silencer according to the first aspect of the invention and regenerable in.situ;
- - Figures 4 and 5 are diagrams showing the location of measurement points during comparative acoustic attenuation tests.
Un silencieux régénérable in situ conforme au second aspect de l'invention comprend une enveloppe extérieure 1 en tôle pleine qui est séparée, c'est-à-dire sans liaison définitive, d'une couche de matériau insonorisant 2 qu'elle contient. Dans cet exemple, il existe un intervalle en sens radial qui fait apparaître un volume annulaire 3 entre l'enveloppe extérieure 1 et le matériau insonorisant 2. Ce volume annulaire 3 est fermé à ses extrémités opposées en sens axial et il est relié à un embout d'air comprimé et d'eau contenant un détergent.An in situ regenerable silencer according to the second aspect of the invention comprises an outer casing 1 made of solid sheet which is separated, that is to say without definitive connection, from a layer of
Le matériau insonorisant 2 est soutenu sur sa face interne par un tissu 5 en fibres synthétiques à texture lâche qui est lui-même soutenu par une cage rigide composée de tubes 6 ; ces derniers sont perforés dans leur partie intérieure au silencieux et, à l'extérieur de celui-ci, ils sont reliés à un tuyau flexible 7 se terminant à une vanne électropneumatique 8 qui fait partie d'un réseau de distribution d'air comprimé.The soundproofing
Le matériau insonorisant 2 est soutenu sur sa face externe 9 par un tissu en fibres synthétiques à texture lâche, de préférence identique au tissu 5 de la face interne, qui prend appui sur un grillage métallique semi-rigide à grosses mailles, en fil plastifié de préférence. Cette paroi externe de maintien 10, non représentée en détail, est espacée de l'enveloppe extérieure 1 par le volume annulaire 3.The soundproofing
La figure 3 montre en coupe transversale un silencieux analogue à celui des figures 1, 2 où les mêmes références désignent les mêmes pièces. Cet exemple est celui d'un premier aspect de l'invention selon lequel l'enveloppe extérieure 1' en tôle pleine est composée de panneaux amovibles. Une armature rigide longitudinale 11 porte des charnières 12 au moyen desquelles des panneaux 13 sont montés pivotants par l'un de leurs bords longitudinaux ; le bord longitudinal opposé permet de fixer chaque panneau 13 à l'armature 11, en position de fermeture. Dans cet exemple aussi, l'enveloppe extérieure 1' est séparée de la couche 2 de matériau insonorisant ; toutefois le volume annulaire 3 des figures 1 et 2 n'est plus nécessaire. Il est donc possible de garnir la face intérieure des panneaux 13 d'une couche 14 de matériau isolant. Cette figure 3 montre aussi que l'armature rigide 11 sert au maintien en position de la paroi externe 10 de la couche de matériau insonorisant 2 à l'aide d'entretoises 15.Figure 3 shows in cross section a silencer similar to that of Figures 1, 2 where the same references designate the same parts. This example is that of a first aspect of the invention according to which the outer casing 1 ′ in solid sheet is made up of removable panels. A longitudinal
Des entretoises analogues (non représentées) peuvent être prévues aussi dans l'exemple des figures 1 et 2 sans que cela supprime la caractéristique de la séparation qui existe entre l'enveloppe extérieure 1 et la couche 2 de matériau insonorisant faisant apparaître le volume annulaire 3 utilisé pour la régénération in situ.Similar spacers (not shown) can also be provided in the example of FIGS. 1 and 2 without this eliminating the characteristic of the separation which exists between the outer casing 1 and the
Dans l'exemple de la figure 3, il est préférable d'utiliser en sens longitudinal des panneaux amovibles distincts facilitant un nettoyage progressif du silencieux pendant son utilisation.In the example of FIG. 3, it is preferable to use separate removable panels in the longitudinal direction facilitating a progressive cleaning of the silencer during its use.
La régénération in situ consiste avec le silencieux des figures 1 et 2 à raccorder l'embout 4 et à ouvrir la vanne 8 pour procéder au nettoyage et au séchage comme expliqué plus haut. Avec le silencieux de la figure 3, on peut soit arrêter le ventilateur, ouvrir tous les panneaux 13 et envoyer de l'extérieur à l'aide d'une buse 16 un jet d'eau sous pression additionnée d'un détergent, ce qui s'exécute en une durée d'une minute par m3 de matériau insonorisant 2 nettoyé. L'eau descend à travers la masse du matériau 2. Il est judicieux de coller à la partie inférieure de celui-ci une bande imperméable 17 ; en donnant à l'ensemble de l'installation une légère pente longitudinale, l'eau de lavage est recueillie, canalisée et évacuée sans difficulté.The in situ regeneration consists with the silencer of FIGS. 1 and 2 in connecting the end piece 4 and in opening the
Du fait que le silencieux de l'invention diffère par sa construction des silencieux classiques, il était utile d'en vérifier la qualité d'affaiblissement acoustique.Because the silencer of the invention differs in its construction from conventional silencers, it was useful to check the quality of sound reduction.
Des essais comparatifs ont été effectués selon la norme française NFS31-021 avec différents silencieux d'aspiration montés sur des ventilateurs électriques BERRY 26 KW type 1560 HM2 qui fournissent un débit de l'ordre de 4,3 m3/seconde sur un circuit de refoulement dont la pression est maintenue par réglage d'un diaphragme à une valeur de 1962 Pa (200 mm colonne d'eau).Comparative tests have been carried out according to French standard NFS31-021 with various suction silencers mounted on BERRY 26 KW type 1560 HM2 electric fans which provide a flow rate of around 4.3 m 3 / second on a circuit of discharge the pressure of which is maintained by adjusting a diaphragm to a value of 1962 Pa (200 mm water column).
Sur la figure 4 sont indiqués les différents points où ont été mesurés les niveaux acoustiques devant la bouche d'aspiration et suivant les angulations et distances prescrites par la norme NF-S31-021.In Figure 4 are indicated the different points where the acoustic levels were measured in front of the suction mouth and according to the angulations and distances prescribed by standard NF-S31-021.
Les mesures ont été faites :
- - sans silencieux (SSS) devant un ventilateur de diamètre D = 0,7 m à une distance de r de 1,35 m ;
- - avec un silencieux classique (SSt) devant un ventilateur de diamètre D 0,8 m à une distance de r de 1,40 m ;
- - avec un silencieux conforme au second aspect de l'invention (SPr) de même longueur que le silencieux classique devant un ventilateur de diamètre D = 0,7 à une distance r = 1,35 m.
- - without silencer (SSS) in front of a fan with diameter D = 0.7 m at a distance of r from 1.35 m;
- - with a conventional silencer (SSt) in front of a fan with a diameter of 0.8 m at a distance of r from 1.40 m;
- - With a silencer in accordance with the second aspect of the invention (SPr) of the same length as the conventional silencer in front of a fan of diameter D = 0.7 at a distance r = 1.35 m.
On a obtenu les résultats suivants qui sont résumés dans le tableau 1.
Lp 1, Lp 2, Lp 3 sont les niveaux acoustiques, Lp est le niveau de pression acoustique surfacique pondéré, Lw est le niveau de puissance acoustique selon la norme NFS 31-021.Lp 1,
On voit donc que, pour le silencieux réalisé selon l'invention, le coefficient d'atténuation acoustique est de 22,1 dBA et pour un silencieux classique il est seulement de 18,4.It can therefore be seen that, for the silencer produced according to the invention, the acoustic attenuation coefficient is 22.1 dBA and for a conventional silencer it is only 18.4.
Sur la figure 5 on indique les différents points où ont été mesurés les niveaux acoustiques dans une installation, le ventilateur comportant un silencieux de bouche 18, un ventilateur électrique 19 et un silencieux classique de sortie 20. Toutes les mesures ont été effectuées à 1 m des parois. Les résultats sont résumés dans le tableau 2.
En variante on peut cloisonner le volume annuiaire 3 par des cloisons transversales et longitudinales pour faire apparaître des caissons susceptibles d'être reliés tous ensemble ou séparément à la conduite d'arrivée du fluide de nettoyage. Dans le premier aspect de l'invention, ces caissons peuvent correspondre à des panneaux amovibles de l'enveloppe extérieure 1. La paroi interne et la paroi externe sont réalisables de nombreuses façons ; mais il est préférable dans de nombreuses circonstances de prévoir un support à texture lâche ayant plus de 50 % de surface vide.As a variant, it is possible to partition the
Claims (14)
Priority Applications (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
AT85400978T ATE36585T1 (en) | 1984-05-18 | 1985-05-17 | IN SITU REGENERABLE SILENCER FOR FAN IN VENTILATION SYSTEMS TRANSPORTED WITH DUST AIR, AND IN SITU REGENERATION PROCESS THEREFORE. |
Applications Claiming Priority (2)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
FR8407711 | 1984-05-18 | ||
FR8407711A FR2564532B1 (en) | 1984-05-18 | 1984-05-18 | IN SITU REGENERABLE MUFFLERS FOR VENTILATORS IN VENTILATION SYSTEMS SUPPLIED WITH DUSTY AIR AND METHOD FOR IN SITU REGENERATION OF SUCH MUFFLERS. |
Publications (2)
Publication Number | Publication Date |
---|---|
EP0165145A1 EP0165145A1 (en) | 1985-12-18 |
EP0165145B1 true EP0165145B1 (en) | 1988-08-17 |
Family
ID=9304115
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
EP85400978A Expired EP0165145B1 (en) | 1984-05-18 | 1985-05-17 | Fan silencer which can be regenerated in situ, for use in ventilation plants fed with dusty air, and process to regenerate this silencer in situ |
Country Status (5)
Country | Link |
---|---|
EP (1) | EP0165145B1 (en) |
AT (1) | ATE36585T1 (en) |
DE (1) | DE3564469D1 (en) |
FR (1) | FR2564532B1 (en) |
IN (1) | IN165301B (en) |
Families Citing this family (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
GB8615909D0 (en) * | 1986-06-30 | 1986-08-06 | Tomac Mining Products Ltd | Fan silencers |
GB2256006B (en) * | 1991-05-21 | 1995-02-22 | Harbury Holdings Inc | An exhaust system and a silencer therefor |
AUPO910697A0 (en) | 1997-09-11 | 1997-10-02 | Hrl Technology Pty Ltd | Improved sound attenuating device |
SE516302C2 (en) * | 1999-03-26 | 2001-12-17 | Paroc Group Oy Ab | Silencer insert for air or gas ducts |
DE102005020303A1 (en) * | 2005-04-30 | 2006-11-09 | Volkswagen Ag | Hose, for use with IC engines, which produces less noise has outer sleeve enclosing foam tube, to inside of which tubular filter, e.g. of non-woven textile, is glued |
Family Cites Families (5)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2056608A (en) * | 1933-12-22 | 1936-10-06 | C F Burges Lab Inc | Silencer |
US2073951A (en) * | 1935-12-09 | 1937-03-16 | Servais Services Ltd | Silencer for gaseous currents |
DE2254159C3 (en) * | 1972-11-04 | 1979-09-27 | Ferroplast Gesellschaft Fuer Metall- Und Kunststofferzeugnisse Mbh, 4322 Sprockhoevel | Silencer for duct fan in underground operation |
US3949830A (en) * | 1975-06-20 | 1976-04-13 | George Koch Sons, Inc. | Fan silencer |
DE3111228C2 (en) * | 1981-03-21 | 1986-07-31 | Filterwerk Mann & Hummel Gmbh, 7140 Ludwigsburg | Method and device for removing soot from the exhaust gases of an internal combustion engine |
-
1984
- 1984-05-18 FR FR8407711A patent/FR2564532B1/en not_active Expired
-
1985
- 1985-05-17 DE DE8585400978T patent/DE3564469D1/en not_active Expired
- 1985-05-17 AT AT85400978T patent/ATE36585T1/en not_active IP Right Cessation
- 1985-05-17 EP EP85400978A patent/EP0165145B1/en not_active Expired
- 1985-07-12 IN IN531/MAS/85A patent/IN165301B/en unknown
Also Published As
Publication number | Publication date |
---|---|
IN165301B (en) | 1989-09-16 |
FR2564532B1 (en) | 1986-09-12 |
DE3564469D1 (en) | 1988-09-22 |
EP0165145A1 (en) | 1985-12-18 |
FR2564532A1 (en) | 1985-11-22 |
ATE36585T1 (en) | 1988-09-15 |
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