Classifications

• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
  • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
  • E04B1/62—Insulation or other protection; Elements or use of specified material therefor
  • E04B1/74—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls
  • E04B1/82—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls specifically with respect to sound only
  • E04B1/84—Sound-absorbing elements
  • E04B1/86—Sound-absorbing elements slab-shaped
• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
  • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
  • E04B1/62—Insulation or other protection; Elements or use of specified material therefor
  • E04B1/74—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls
  • E04B1/82—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls specifically with respect to sound only
  • E04B2001/8263—Mounting of acoustical elements on supporting structure, e.g. framework or wall surface
  • E04B2001/8281—Flat elements mounted parallel to a supporting surface with an acoustically active air gap between the elements and the mounting surface
• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
  • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
  • E04B1/62—Insulation or other protection; Elements or use of specified material therefor
  • E04B1/74—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls
  • E04B1/82—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls specifically with respect to sound only
  • E04B1/84—Sound-absorbing elements
  • E04B2001/8423—Tray or frame type panels or blocks, with or without acoustical filling
  • E04B2001/8433—Tray or frame type panels or blocks, with or without acoustical filling with holes in their face
  • E04B2001/8438—Slot shaped holes
• • E—FIXED CONSTRUCTIONS
  • E04—BUILDING
  • E04B—GENERAL BUILDING CONSTRUCTIONS; WALLS, e.g. PARTITIONS; ROOFS; FLOORS; CEILINGS; INSULATION OR OTHER PROTECTION OF BUILDINGS
  • E04B1/00—Constructions in general; Structures which are not restricted either to walls, e.g. partitions, or floors or ceilings or roofs
  • E04B1/62—Insulation or other protection; Elements or use of specified material therefor
  • E04B1/74—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls
  • E04B1/82—Heat, sound or noise insulation, absorption, or reflection; Other building methods affording favourable thermal or acoustical conditions, e.g. accumulating of heat within walls specifically with respect to sound only
  • E04B1/84—Sound-absorbing elements
  • E04B2001/8423—Tray or frame type panels or blocks, with or without acoustical filling
  • E04B2001/8442—Tray type elements

Definitions

• the present invention relates to the design and production of sound absorption devices intended for the acoustic correction of premises or for the soundproofing of boxes or casings of noisy machines.
• a device is to be placed in front of a support wall defining the room or box.
• the invention therefore proposes to provide absorption devices of the aforementioned type, the characteristic curve of which is practically of equal performance level for a whole predetermined range of frequencies, and more particularly in the range of audible frequencies.
• the device according to the invention comprises in combination a perforated embossed sheet active in reflection of acoustic waves and a layer of porous absorbent material which is fixed against said sheet so as to be arranged between the latter and the support wall.
• the layer of porous material strongly absorbs the resonances, so that the characteristic curve of the absorption capacity of the device as a whole is smoothed.
• the absorption device is placed at a distance from the support wall so as to provide an air space between the layer of absorbent material and the support wall.
• One of the major interests of the invention here is to lead to elements for absorbing sound waves which are easily configurable as a function of the sound spectrum to be corrected, by playing on the respective thicknesses of the air space and of the absorbent layer which separates it from the reflecting sheet.
• the perforations of the embossed sheet are slots arranged in regular meshes as in a sheet of expanded metal.
• the porous absorbent material is of the cellular type, such as a melamine or polyurethane foam.
• the porous absorbent material is a felt, in particular based on natural or artificial fibers, in particular based on glass wool or rock wool.
• the thickness of the layer of porous absorbent material is between 5 and 200 mm and the thickness of the embossed sheet is between 0.5 and 1.5 mm.
• the perforated embossed sheet is linked to the layer of porous material so as to constitute a self-supporting assembly in which the sheet has the function of ensuring mechanical strength.
• the sheet has the function of ensuring mechanical strength.
• it is also used to fix the device in front of a support wall to be soundproofed.
• it protects the absorbent layer from external aggressions.
• the device according to the invention advantageously has modular elements to be assembled on site in front of a support wall.
• the layer of absorbent material is held on the embossed sheet perforated by flaps obtained by folding the edges of the sheet.
• the layer of porous absorbent material is fixed to the sheet by means of clips or staples.
• the layer of absorbent material is fixed to the sheet by means of strips of adhesive material.
• FIG. 1 is a sectional view of a first embodiment of the invention
• FIG. 2 is a perspective view of the sheet of the absorbent element of FIG. 1,
• FIG. 3 is a partial detail view of the outer face of the sheet of Figure 2
• FIG. 5 is a top view of the layer of absorbent material of the absorbent member of Figure 4
• FIG. 9 is a sectional view illustrating the attachment of the embodiment of Figure 4 on the support wall
• FIG. 10 is a sectional view illustrating the attachment of the embodiment of Figure 3 on the support wall
• the subject of the invention is an acoustic element operating by reflection and absorption of air vibrations or acoustic vibrations and intended for the acoustic correction of noisy rooms or for the soundproofing of boxes or enclosures containing noisy devices.
• These may for example be noisy industrial premises, such as wind tunnels, or buildings open to the public such as hospitals.
• the invention also applies to boxes containing noisy machines.
• the acoustic element according to the invention is intended to be placed on the interior walls of soundproof premises or enclosures, or in the vicinity of these walls.
• the absorbent element according to the invention essentially consists of a sheet 1 which has perforations and which is of embossed shape and a layer 2 of porous, cellular or fibrous absorbent material, which is fixed to the inner face 6 of prison
• the sheet 1 has a low perforation rate, that is to say that the proportion of its surface which is occupied by holes or perforations is small compared to its total surface. This rate is for example at most a quarter.
• the sheet 1 is rectangular and its four edges 3 and 4 are folded 90 degrees towards the inner face 6 of the sheet 1 so as to constitute a housing rectangular in which the layer 2 of absorbent material is placed.
• the two opposite edges 4 of the sheet 1 are bent again at 90 degrees so as to obtain flaps 5 parallel to the inner face of the sheet 1.
• the height of the side walls 3 and 4 corresponds to the thickness of the absorbent layer 2 and the flaps 5 are produced after the introduction of the layer 2 of absorbent material. They thus protect the edges of the absorbent layer, mainly from the mechanical point of view.
• the sheet 1 is a metal sheet made for example of aluminum, steel or stainless steel. This sheet 1 is thin, preferably between 0.5 and 1.5 mm.
• the sheet is perforated, that is to say that it has small slots arranged in regular meshes. It is also embossed, that is to say that it has bumps and hollows in a repeated regular distribution. In the case under consideration, it is deformed in such a way that the slots are pushed back, when it is produced, in a plane different from the initial plane of the sheet. II it is thus a perforated embossed sheet of the type of an expanded metal plate.
• FIG. 3 is a partial view on a large scale of the external face 7 of the sheet 1.
• two rows of slots 8 which have a first edge 9 which is in the plane of the outer face 7 of the sheet and a deformed edge 1 1 which has been pushed back above the outer face 7 during making the slots.
• the slots have a certain height in the direction perpendicular to the plane of the sheet.
• the two rows of slots 8 are staggered with respect to one another, in staggered rows, with a slight overlap of the slots of a row with respect to the slots of the neighboring row.
• slits are made by means of a saw-blade tool which tears the metal and then bends it.
• the variable parameters are the shape of the tool which gives the length of the slot and the penetration depth of the latter into the metal which gives the width of the mesh.
• the perforated embossed sheet obtained corresponds to the following dimensions:
• the absorbent porous layer it is possible, for example, to use cellular organic materials such as melamine foam or polyurethane foam, or fibrous materials such as cotton, polyester, polypropylene, polychloroprene felts, etc. or mineral wools, for example glass wool or rock wool.
• cellular organic materials such as melamine foam or polyurethane foam
• fibrous materials such as cotton, polyester, polypropylene, polychloroprene felts, etc. or mineral wools, for example glass wool or rock wool.
• the height of the edges 3 and 4 corresponds to the thickness of the absorbent layer and can be between 5 and 200 mm.
• the perforation rate and the perforation density have been optimized for sound absorption in the range of frequencies audible by the human being, in order to obtain a resistivity to the passage of air of between 500 and 3300 N s / m 3 .
• these data are not limiting. They may vary in particular depending on the applications of the invention.
• the sheet When such a sheet is placed in front of a reflecting support, namely the wall of the enclosure to be soundproofed, the sheet functions as an absorbent material which has a selective character depending on the reflection phenomena which occur between the support wall and the inner face 6 of the sheet 1.
• C is the speed of sound in the air, for example 343 m / s at 20 ° C
• d is the thickness of the air space, i.e. the distance between the sheet and support wall.
• the values of the sound absorption coefficients take a minimum value and this results in significant dips in the curve. absorption of the absorption device.
• the layer of absorbent material 2 is associated with the sheet 1, this layer 2 being placed between the sheet 1 and the support wall, being applied to the sheet 1. In this way, the cavity resonances are absorbed by the absorbent material and the values of the absorption coefficients become homogeneous.
• the method of fixing the layer of absorbent material on the sheet does not modify the structure of the perforated embossed sheet, that is to say that the absorbent material does not obstruct the slots 8, so that that the resistivity to the passage of air from the sheet is not changed.
• FIGS. 1 and 2 A first method is illustrated in FIGS. 1 and 2.
• the sheet is folded on at least two sides and the layer 2 is placed between the sheet and the folded edges.
• Mechanical fixing can also be provided by means of clips or staples. This fixing is especially effective for layers of semi-rigid absorbent material.
• the sheet is shaped so that the absorbent layer is protected by the sheet around its edges.
• FIGS. 4 and 5 Another fixing method is illustrated in FIGS. 4 and 5. Strips of adhesive material 13 having a small width, for example between 5 and 20 mm, and spaced parallel to each other are deposited on the layer 2 of absorbent material. , for example with a distance between two neighboring strips of between 50 and 500 mm. The layer of absorbent material 2 is then placed on the inner face 6 of the sheet 1, the adhesive strips 13 being pressed against the sheet 1 on which they adhere while retaining the layer 2 of sound absorbing material.
• Another possibility is to fix the layer of absorbent material using a hot compression process, a layer of absorbent material being strongly compressed hot on the sheet. During this operation, the absorbent material adheres to the asperities of the embossed sheet which constitute contact points without blocking the perforations. It is assumed here that the material contains a binder which then ensures fixing by gluing.
• the fixing of the acoustic device thus produced on the support wall is carried out by means of fixing members which bear on the sheet 1, since the latter generally benefits from mechanical resistance characteristics linked to its metallic nature which the layer of porous material.
• the fixing members may advantageously be constituted by profiles connecting the sheet 1 to the support wall at the level of deformations of the sheet where it is devoid of a layer of porous material, or by tie rods passing through all the layers of the acoustic device at level of the flaps 5 of the sheet which are formed to overlap the edges of the layer of porous material.
• the method of fixing such members in the support wall can be in particular by screwing, possibly in dowels previously put in place when the nature of the support wall requires it.
• Figure 9 illustrates, in sectional view, such a method of attachment, showing how an empty space is formed between the layer of porous material 2 and the support wall.
• a tie rod 1 which crosses the sheet 1, the layer 2 of acoustic material, and the flap 5.
• the fixing member is completed by a washer 12 and by a hollow spacer 14 which is interposed on the tie rod 1 1 when it’s in place. It is then fixed in the support wall 15, for example by involving a dowel 16.
• the washer 12 ensures the support of the flap 5 on the spacer 15, which maintains a distance from the wall 15 which corresponds to the desired thickness of the air gap.
• Layer 2 is not subject to any mechanical stress which would risk altering its acoustic qualities.
• the free ends of the side walls 4 are advantageously folded 90 degrees outward to form tabs 10 which are fixed on the support wall.
• the height of the side walls 4 corresponds to the thickness of the air gap formed, that is to say to the distance provided between the sheet 1 and the support wall. This height corresponds to the thickness of layer 2 increased by the thickness of free air provided between layer 2 and the support wall.
• FIG. 10 illustrates, in sectional view, a method of fixing the device of FIG. 4.
• the outer flaps 10 of two neighboring devices are placed one on the other and crossed by a nail or similar member 17 which is fixed in the support wall 15 by pressing the flaps 10 on this wall, thus ensuring the desired thickness of the air space.
• Figure 6 shows the curves of the sound absorption coefficient as a function of the frequency of the embossed perforated sheet placed in front of a wall for air gaps varying between 20 and 1 00 mm. It can be seen that, for all the curves, there are one or more significant depressions in the absorption curve, the frequency corresponding to these depressions being inversely proportional to the thickness of the air space.
• Figures 7 and 8 are corresponding curves for devices comprising a reflective sheet and an absorbent layer as provided by the invention.
• the layer 2 of absorbent material is made of melamine foam and has a thickness of 60 mm.
• the space between the support wall and the porous layer 2 is minimal.
• FIG. 8 is an exemplary embodiment in which the layer 2 is also made of melamine foam and its thickness is 40 mm.
• the device according to the invention is placed 60 mm from the support wall, the thickness of the air space formed therefore being 100 mm.
• Figures 1 1 and 12 show, still in section, a method of fixing another embodiment of the device according to the invention.
• the layer 20 of insulating material is fixed by gluing, by means of a layer of adhesive or by hot compression, on a sheet 21 which projects from the layer 20 on the sides, in a straight line, so as to provide between two neighboring devices, advantageously in the form of identical slabs, a free space of acoustic material below the extensions 25 of the sheets 20.
• a spacer 22 is associated with the assembly, to be fixed on the support wall 15. It carries on its free end a profile 23 (FIG. 12), with a common section in the shape of an overturned omega, which is fixed on its central part, for example by a rivet 24.
• This profile 23 is housed with the end of the spacer 23 in the aforementioned free space, in a position where the extensions 25 of the sheets 21 rest on lateral plates 26 of the profile 23.
• the extensions 25 of the sheets 20 are held on the profile 23 by means of a clip 27 which comes to stop in the profile 23 and which also constitutes a joint cover between the respective extensions 25 of the sheets of the two neighboring devices.
• the device according to the invention can be used in particular in the building industry, for example for the production of absorbent dihedrons for anechoic rooms, absorbent ceilings, or absorbent wall cladding.
• the invention applies in particular in wind tunnels, industrial buildings, social-cultural buildings, the hospital sector.
• the invention can also be used with profit in the industry to produce acoustic absorbent facings or silent devices, in particular in shipbuilding or aeronautics, the railway industry, the automotive industry, the acoustic cowling of noisy machines, heating and air conditioning equipment, agricultural or military equipment, including public works vehicles, the IT industry and glass recovery containers.
• the perforated embossed sheet is used to ensure the mechanical resistance of the sound absorption device by constituting a stiffening support for the acoustic wave absorption layer and providing its protection.
• the elements according to the invention can be marketed by combining with the perforated embossed sheet and the acoustic absorption layer of the fixing to the support wall for which they are intended which provide an air space of predetermined thickness.
• the layer of absorbent material is disposed fixed against the perforated embossed sheet, on the internal face of the latter, in particular by bonding to the roughness that it presents because it is embossed, and said layer is thus disposed between said sheet and the support wall for which it is intended, and at a distance from this support wall which is chosen in conjunction with the thickness of the layer of absorbent material to ensure a desired effect in correcting a sound spectrum in a range of determined frequency.
• the perforated embossed sheet is itself shaped to impose a predetermined distance between the internal face of the absorbent layer and the support wall.

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• Physics & Mathematics (AREA)
• Acoustics & Sound (AREA)
• Engineering & Computer Science (AREA)
• Architecture (AREA)
• Electromagnetism (AREA)
• Civil Engineering (AREA)
• Structural Engineering (AREA)
• Building Environments (AREA)
• Soundproofing, Sound Blocking, And Sound Damping (AREA)
• Window Of Vehicle (AREA)
• Meat, Egg Or Seafood Products (AREA)
• External Artificial Organs (AREA)

Priority Applications (2)

Applications Claiming Priority (2)

Publications (1)

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ID=8865735

Family Applications (1)

Country Status (5)

Cited By (2)

Families Citing this family (2)

Citations (7)

• 2001
  • 2001-07-16 FR FR0109707A patent/FR2827419B1/fr not_active Expired - Fee Related
• 2002
  • 2002-07-16 DE DE60228257T patent/DE60228257D1/de not_active Expired - Lifetime
  • 2002-07-16 AT AT02787155T patent/ATE404750T1/de not_active IP Right Cessation
  • 2002-07-16 WO PCT/FR2002/002518 patent/WO2003008725A1/fr active IP Right Grant
  • 2002-07-16 EP EP02787155A patent/EP1407091B1/de not_active Revoked

Patent Citations (7)

Non-Patent Citations (1)

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