GB1579897A - Sound absorber - Google Patents

Sound absorber Download PDF

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Publication number
GB1579897A
GB1579897A GB23500/77A GB2350077A GB1579897A GB 1579897 A GB1579897 A GB 1579897A GB 23500/77 A GB23500/77 A GB 23500/77A GB 2350077 A GB2350077 A GB 2350077A GB 1579897 A GB1579897 A GB 1579897A
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United Kingdom
Prior art keywords
sound
layer
foil
absorber according
sound absorber
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Expired
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GB23500/77A
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Becker Wilhelm AB
Original Assignee
Becker Wilhelm AB
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Publication date
Application filed by Becker Wilhelm AB filed Critical Becker Wilhelm AB
Publication of GB1579897A publication Critical patent/GB1579897A/en
Expired legal-status Critical Current

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Classifications

    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B5/00—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts
    • B32B5/22—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed
    • B32B5/24—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer
    • B32B5/26—Layered products characterised by the non- homogeneity or physical structure, i.e. comprising a fibrous, filamentary, particulate or foam layer; Layered products characterised by having a layer differing constitutionally or physically in different parts characterised by the presence of two or more layers which are next to each other and are fibrous, filamentary, formed of particles or foamed one layer being a fibrous or filamentary layer another layer next to it also being fibrous or filamentary
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B3/00—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form
    • B32B3/10—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form characterised by a discontinuous layer, i.e. formed of separate pieces of material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B15/00—Layered products comprising a layer of metal
    • B32B15/14—Layered products comprising a layer of metal next to a fibrous or filamentary layer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B23/00—Layered products comprising a layer of cellulosic plastic substances, i.e. substances obtained by chemical modification of cellulose, e.g. cellulose ethers, cellulose esters, viscose
    • B32B23/04—Layered products comprising a layer of cellulosic plastic substances, i.e. substances obtained by chemical modification of cellulose, e.g. cellulose ethers, cellulose esters, viscose comprising such cellulosic plastic substance as the main or only constituent of a layer, which is next to another layer of the same or of a different material
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B27/00—Layered products comprising a layer of synthetic resin
    • B32B27/12—Layered products comprising a layer of synthetic resin next to a fibrous or filamentary layer
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B3/00—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form
    • B32B3/26—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer
    • B32B3/266—Layered products comprising a layer with external or internal discontinuities or unevennesses, or a layer of non-planar form; Layered products having particular features of form characterised by a particular shape of the outline of the cross-section of a continuous layer; characterised by a layer with cavities or internal voids ; characterised by an apertured layer characterised by an apertured layer, the apertures going through the whole thickness of the layer, e.g. expanded metal, perforated layer, slit layer regular cells B32B3/12
    • 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
    • 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
    • G10K11/162—Selection of materials
    • G10K11/168—Plural layers of different materials, e.g. sandwiches
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2262/00—Composition or structural features of fibres which form a fibrous or filamentary layer or are present as additives
    • B32B2262/02—Synthetic macromolecular fibres
    • B32B2262/0276—Polyester fibres
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2262/00—Composition or structural features of fibres which form a fibrous or filamentary layer or are present as additives
    • B32B2262/06—Vegetal fibres
    • B32B2262/062—Cellulose fibres, e.g. cotton
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2305/00—Condition, form or state of the layers or laminate
    • B32B2305/02—Cellular or porous
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/10—Properties of the layers or laminate having particular acoustical properties
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/50—Properties of the layers or laminate having particular mechanical properties
    • B32B2307/51—Elastic
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B32—LAYERED PRODUCTS
    • B32B—LAYERED PRODUCTS, i.e. PRODUCTS BUILT-UP OF STRATA OF FLAT OR NON-FLAT, e.g. CELLULAR OR HONEYCOMB, FORM
    • B32B2307/00—Properties of the layers or laminate
    • B32B2307/50—Properties of the layers or laminate having particular mechanical properties
    • B32B2307/56—Damping, energy absorption
    • 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
    • E04B2001/8457—Solid slabs or blocks
    • E04B2001/8461—Solid slabs or blocks layered
    • 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
    • E04B2001/8457—Solid slabs or blocks
    • E04B2001/8476—Solid slabs or blocks with acoustical cavities, with or without acoustical filling

Description

(54) IMPROVEMENTS IN OR RELATING TO A SOUND ABSORBER (71) We, AKTIEBOLAGET WILHELM BECKER, a Swedish company, of Fack, S-102 70 Stockholm, Sweden, do hereby declare the invention, for which we pray that a patent may be granted to us, and the method by which it is to be performed, to be particularly described in and by the following statement: - The present invention is related to a sound absorber and more particularly to a sound absorbing material in the form of a plate or sheet comprising several layers, i.e.
a laminated sound absorber, which may be, for example, suitable for use in connection with the sound insulation of motors, machines, or tools.
It is previously known to use one or more sheets or layers of sound absorbing material, for instance of fibrous or foamed materials, in order to attenuate or eliminate sounds from different sound sources, for instance motors and machines. Many such sound absorbing materials have had open pores or cells in order to provide the best possible absorption of the sound waves in the sound attenuating layers. If the above described sound absorbing layers have a covering layer that is rigid or that has a solid surface rather than a cellular or a fibrous surface, sound waves initially incident on the covering layer will tend to be reflected back by the covering layer rather than being transmitted through the covering layer, so that only a portion of the energy of the sound waves incident on the covering layer can be absorbed in the sound absorbing layers.Therefore, the energy absorbed by the sound absorbing layers is substantially reduced and thus the overall effect of the sound absorbing layers is reduced.
If sound absorbing layers of a material having open pores or cells are used for sound attenuation of motors or machines and, as is usually the case, are positioned adjacent the motor or the machine, the exposed surface of the sound absorbing layer which faces the motor or machine will tend to be made dirty quickly with oil and grease penetrating through the open pores into the absorbing layer. The oil and grease will reduce the efficiency of the sound ab- sorbing material and thus the effect of the sound absorbing layer is quickly reduced.
The presence of the dirt can also contribute to an increase risk of iire. Due to the presence of the open pores the cleaning of the surface of such a sound absorbing layer is difficult and time consuming, and it is virtually impossible to clean an oil or grease impregnated foamed plastics member in a satisfactory manner. In order to eliminate the above described disadvantage of using sound absorbing layers having open pores it has previously been suggested to provide the sound absorbing layer with a covering layer, for instance a foil or thin sheet, which is air-tight and thus, prevents the penetration of dirt and other contaminations into the cells of the sound absorbing layer. An air-tight surface layer on the sound absorbing layer also permits simple and complete cleaning of the exposed surface.However, the provision of an air-tight surface layer on the sound absorbing layer has resulted in a substantial decrease of the absorption in the sound absorbing layer due to the resulting reflection of the incident sound waves, as mentioned above.
According to this invention there is previded a laminated sound absorber comprising a flexible sound absorbing layer and a covering layer which is provided on one surface of the sound absorbing layer, thc covering layer comprising an elastic spacing layer which is porous to air and which is attached to the sound absorbing layer and an air-tight thin foil provided on the outside of the spacing layering, the foil being attached to the spacing layer at a number of predetermined spaced points the areas of the foil between said spaced points being free to vibrate when exposed to sound.
The reflection of sound at the outside of the sound absorber is decreased to a minimum by the thin, air-tight foil and sound waves impinging against the foil or sheet are propagated by membrane action of the foil to the inner portion of the sound absorber without or with only a minor reflection at the foil surface. The spacing layer which is porous to air so that air vibrations easily can pass therethrough.
Preferably the foil has a very low weight and a low stiffness, so that the largest portion of the sound energy of the sound waves striking the foil passes through the foil.
However, the sound penetration decreases with increased frequency.
Since the spacing layer is elastic and thus flexible and the foil is attached to this spacing layer only in a number of spaced points or spots, the advantage is obtained that, if the sound absorbing layer also is flexible, the sound absorber can be shaped to fit bent or rounded surfaces, for instance in an engine housing, and thus easily can be adapted for different applications.
In order to maintain the good absorbing properties of the porous absorber at high frequencies, up to 3000 Hz, the surface weight of the foil should preferably not be higher than 20 g!m2. The sound frequency limits is moved upwards with a lighter foil and downwards with a heavier foil. It is preferable that the largest portion of the foil may move freely with regard to the surface of the absorber. For practical reasons, among other things in order to improve the mechanical properties of the surface, the foil must be attached to the surface of the absorber. However, during the mounting of the absorber in position the foil can become tensioned, as a drum head, over the surface of the porous absorber.
In practice it has been found that in such a case the foil, together with the structure of the absorber forms, an effective reflector surface for the impinging sound energy.
Besides a small mass resistance against the sound waves a substantial stiffness resistance is added. The effect of the porous absorber is thus decreased at the higher frequencies where a maintained absorption oapacity is desired.
To overcome this disadvantage in a preferred embodiment of the invention a spacer having such properties that the freedom of movement of the membrane is not really decreased or mounting the absorber is inserted between the membrane and the absorber. Because the membrane can be attached to the spacer, mechanical properties are obtained which are comparable with the properties obtained if the foil is attached directly to the porous absorber.
In order that the invention may be more readily understood and so that further features thereof may be appreciated the invention will now be described by way of example with reference to the accompanying drawings in which: - Figure 1 is a section through a laminated sound absorber in accordance with the invention having a spacing layer of a perforated material, and Figure 2 is a section through a laminated sound absorber having a spacing layer of cotton wool.
The sound absorber shown in Figure 1 comprises a layer 10 of sound absorbing material, for instance felt or cellular plastics material, and a covering layer which is pm vided on the surface of the sound absorbing layer against which the sound waves impinge and which consists of a spacing layer 11 covered by an air-tight thin foil 12.
The spacing layer 11 consists of a soft elastic material, for instance cellular polyurethane plastics material, and is provided with a large number of large, closely adjacent holes or pores 13. The thin foil 12 is attached to the spacing layer and, therefore, the foil is only rigidly connected to the spacing layer in certain points or spots due to the holes or pores in the spacing layer. The other portions of the foil thus have a substantial freedom of movement with regard to the spacing layer, so that the impinging sound waves can pass into the sound absorber without substantial re flection at the foil surface. The foil is preferably a plastics material foil, for instance a uniform foil of unsaturated polyester plastics material having a thickness of 10-100 EL (microns).The spacing layer preferably has a thickness of 2-10 mm and and the pores preferably have a diameter of about 2-10 mm. The layer 10 of sound absorbing material preferably has a thickness of 5-100 mm.
Many different materials can be used for the sound absorbing layer and the spacing layer. The sound absorbing layer can be flexible to make it possible to mount the sound absorber on curved surfaces and in order to enable a sound absorbing plate to be pre-formed. As mentioned above, felt is a very convenient material but also cellular plastics materials and mineral wool can be used. The spacing layer can consist of perforated cellular plastics material or cellular plastics material with large pores or of granules of cellular plastics material having a convenient size and glued or otherwise adhered to the sound absorbing layer and to the foil. Alternatively, the spacing layer can consist of a cotton wool or similar loose fibrous layer 15, as shown in Figure 2, for instance of a straight chain polyester fibre as sold under the Trade Mark TERY LENE which may be acrylic treated. The layer 15 can be secured in position with an acrylic adhesive. In view of the function of the spacing layer it is important, however, that the layer is elastic and allows air and sound waves to pass through it easily. The foil may be a metal foil, or a plastics material foil can be used which is provided with a metal layer having, at a maximum, the same weight as the plastics foil. Thus the membrane may be a laminate. This metal layer may also be perforated. The metal layer is used for increasing the stability and strength of the plastics material foil or for making the surface thereof heat reflecting. The membrane may additionally or alternatively be reinforced with a net.
With the above described sound absorbing structure the sound reflection at the airtight covering layer can be decreased to be about 10 to 20% of the incident sound energy. In prior art structures where the air-tight covering layer has been attached to the sound absorbing layer typically a reflection of about 40 to 80% has been caused. Thus, the invention provides a substantial increase in efficiency when compared with the prior art.
Whilst the invention has been described with reference to sound absorbers primarily intended for sound insulation of motors engines and machines, sound absorbers in accordance with the invention can of course also be used in all cases where sound attenuation or sound insulation is to be provided.
WHAT WE CLAIM IS:- 1. A laminated sound absorber comprising a flexible sound absorbing layer and a covering layer which is provided on one surface of the sound absorbing layer, the covering layer comprising an elastic spacing layer which is porous to air and which is attached to the sound absorbing layer and an air-tight thin foil provided on the outside of the spacing layer, the foil being attached to the spacing layer at a number of predetermined spaced points, the areas of the foil between said spaced points being free to vibrate when exposed to sound.
2. A sound absorber according to claim 1, wherein the spacing layer is provided with a number of large through holes.
3. A sound absorber according to claim 2, in that the holes in the spacing layer have a diameter of 2-10 mm.
4. A sound absorber according to claim 1, 2 or 3, wherein the spacing layer is perforated cellular plastics material layer having a thickness of 2-10 mm.
5. A sound absorber according to claim 1, wherein the spacing layer consists of cellular plastics material granules arranged between the sound absorbing layer and the foil.
6. A sound absorber according to claim 2, wherein the spacing layer is cotton wool or like fibrous material.
7. A sound absorber according to claim 6, wherein the said like fibrous material consists of straight chain polyester fibres.
8. A sound absorber according to any of the preceding claims, wherein the sound absorbing layer is a felt having a thickness of about 5-100 mm.
9. A sound absorber according to any of claims 1 to 7 characterized in that the sound absorbing layer is cellular plastics material having a thickness of 5-100 mm.
10. A sound absorber according to any one of the preceding claims wherein the membrane comprises a plastics material foil having a thickness of about 10-100 .
11. A sound absorber according to claim 12, wherein the foil is provided with a metal layer having a surface weight equal to of less than that of the foil.
12. A sound absorber according to claim 13, wherein the said metal layer is perforated.
13. A sound absorber according to any one of the preceding claims wherein the membrane is a foil which is reinforced by a net.
14. A sound absorber according to any of the preceding claims, wherein the membrane is a foil which is laminated.
15. A sound absorber substantially as herein described with reference to, and as shown in, Figure 1 of the accompanying drawings.
16. A sound absorber substantially as herein described with reference to, and as shown in, Figure 2 of the accompanying drawings.
**WARNING** end of DESC field may overlap start of CLMS **.

Claims (16)

**WARNING** start of CLMS field may overlap end of DESC **. the membrane may be a laminate. This metal layer may also be perforated. The metal layer is used for increasing the stability and strength of the plastics material foil or for making the surface thereof heat reflecting. The membrane may additionally or alternatively be reinforced with a net. With the above described sound absorbing structure the sound reflection at the airtight covering layer can be decreased to be about 10 to 20% of the incident sound energy. In prior art structures where the air-tight covering layer has been attached to the sound absorbing layer typically a reflection of about 40 to 80% has been caused. Thus, the invention provides a substantial increase in efficiency when compared with the prior art. Whilst the invention has been described with reference to sound absorbers primarily intended for sound insulation of motors engines and machines, sound absorbers in accordance with the invention can of course also be used in all cases where sound attenuation or sound insulation is to be provided. WHAT WE CLAIM IS:-
1. A laminated sound absorber comprising a flexible sound absorbing layer and a covering layer which is provided on one surface of the sound absorbing layer, the covering layer comprising an elastic spacing layer which is porous to air and which is attached to the sound absorbing layer and an air-tight thin foil provided on the outside of the spacing layer, the foil being attached to the spacing layer at a number of predetermined spaced points, the areas of the foil between said spaced points being free to vibrate when exposed to sound.
2. A sound absorber according to claim 1, wherein the spacing layer is provided with a number of large through holes.
3. A sound absorber according to claim 2, in that the holes in the spacing layer have a diameter of 2-10 mm.
4. A sound absorber according to claim 1, 2 or 3, wherein the spacing layer is perforated cellular plastics material layer having a thickness of 2-10 mm.
5. A sound absorber according to claim 1, wherein the spacing layer consists of cellular plastics material granules arranged between the sound absorbing layer and the foil.
6. A sound absorber according to claim 2, wherein the spacing layer is cotton wool or like fibrous material.
7. A sound absorber according to claim 6, wherein the said like fibrous material consists of straight chain polyester fibres.
8. A sound absorber according to any of the preceding claims, wherein the sound absorbing layer is a felt having a thickness of about 5-100 mm.
9. A sound absorber according to any of claims 1 to 7 characterized in that the sound absorbing layer is cellular plastics material having a thickness of 5-100 mm.
10. A sound absorber according to any one of the preceding claims wherein the membrane comprises a plastics material foil having a thickness of about 10-100 .
11. A sound absorber according to claim 12, wherein the foil is provided with a metal layer having a surface weight equal to of less than that of the foil.
12. A sound absorber according to claim 13, wherein the said metal layer is perforated.
13. A sound absorber according to any one of the preceding claims wherein the membrane is a foil which is reinforced by a net.
14. A sound absorber according to any of the preceding claims, wherein the membrane is a foil which is laminated.
15. A sound absorber substantially as herein described with reference to, and as shown in, Figure 1 of the accompanying drawings.
16. A sound absorber substantially as herein described with reference to, and as shown in, Figure 2 of the accompanying drawings.
GB23500/77A 1976-06-03 1977-06-02 Sound absorber Expired GB1579897A (en)

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
SE7606268A SE402142B (en) 1976-06-03 1976-06-03 LAMINATED SOUND ABSORBENT

Publications (1)

Publication Number Publication Date
GB1579897A true GB1579897A (en) 1980-11-26

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Family Applications (1)

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GB23500/77A Expired GB1579897A (en) 1976-06-03 1977-06-02 Sound absorber

Country Status (8)

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DE (1) DE2724172A1 (en)
DK (1) DK145310C (en)
FI (1) FI59134C (en)
FR (1) FR2353392A1 (en)
GB (1) GB1579897A (en)
IT (1) IT1084993B (en)
NO (1) NO149007C (en)
SE (1) SE402142B (en)

Cited By (14)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0095125A2 (en) * 1982-05-22 1983-11-30 Metzeler Schaum Gmbh Plane element for sound-wave absorption
DE9406667U1 (en) * 1994-04-21 1995-01-26 Voewa Isoliermaterial Gmbh Web made of heat-insulating material
EP0849164A3 (en) * 1996-12-21 2001-03-07 EADS Airbus GmbH Wall element
FR2817995A1 (en) * 2000-12-08 2002-06-14 Cera Acoustic absorption complex e.g. for vehicle noise has perforated screen to allow passage of sound waves returned by reflective medium
EP1306205A1 (en) * 2001-10-29 2003-05-02 Johnson Controls GmbH Covering element for the interior of a vehicle and method for fabricating the same
EP1493623A1 (en) * 2003-07-04 2005-01-05 Renault s.a.s. Separation wall between two interior compartments of a vehicle
EP1654461A2 (en) * 2003-08-07 2006-05-10 BLACK & DECKER INC. Portable air compressor
EP2146005A2 (en) * 2008-07-18 2010-01-20 BIG Bau und Immobilienges.m.b.H. Noise protection element
GB2461909A (en) * 2008-07-17 2010-01-20 South Bank Univ Entpr Ltd Sound absorbing device
US7762790B2 (en) 2007-02-05 2010-07-27 Black & Decker Inc. Air compressor
WO2011047429A1 (en) * 2009-10-21 2011-04-28 Bellmax Acoustic Pty Ltd Acoustic panel
WO2012006663A1 (en) * 2010-07-13 2012-01-19 Bellmax Acoustic Pty Ltd An acoustic panel
WO2013156739A1 (en) * 2012-04-20 2013-10-24 Aircelle Thin panel for absorbing sound waves emitted by a turbofan of an aircraft nacelle, and nacelle provided with such a panel
WO2020136532A1 (en) * 2018-12-26 2020-07-02 3M Innovative Properties Company Acoustic article, acoustic assembly and method of making and using an acoustic article

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* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
SE420750B (en) * 1978-11-17 1981-10-26 Ingemanssons Ingenjorsbyra Ab SOUND-INSULATING BUILDING ELEMENT WITH GREAT STUFF
SE424654B (en) * 1979-05-11 1982-08-02 Ifm Akustikbyran Ab hygienic absorbent
US4301890A (en) * 1979-12-06 1981-11-24 Lord Corporation Sound-absorbing panel
US4340129A (en) * 1980-05-01 1982-07-20 Cabot Corporation Acoustical laminate construction and attenuated systems comprising same
US4468431A (en) * 1983-11-17 1984-08-28 Iml Corporation Polyimide composite
CN104594515A (en) * 2014-12-05 2015-05-06 城林环保技术（上海）有限公司 Novel sound absorbing and attenuating board

Family Cites Families (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2081952A (en) * 1934-12-17 1937-06-01 Johns Manville Acoustical construction
DE1002939B (en) * 1953-12-30 1957-02-21 Dr Friedrich Karl Schroeder Sound absorbing device made of a porous absorbent layer and a thin cover layer
US3380206A (en) * 1965-09-29 1968-04-30 Soundlock Corp Lay-in acoustical ceiling panel with flexible diaphragms
DE2001202A1 (en) * 1970-01-13 1971-09-02 Wilhelmi Holzwerk Composite sound insulating panels with vary- - ing zone density
DE2408028B2 (en) * 1974-02-20 1978-05-11 Fa. Carl Freudenberg, 6940 Weinheim Sound absorbing plate

Cited By (29)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0095125A3 (en) * 1982-05-22 1984-09-26 Metzeler Schaum Gmbh Plane element for sound-wave absorption
EP0095125A2 (en) * 1982-05-22 1983-11-30 Metzeler Schaum Gmbh Plane element for sound-wave absorption
DE9406667U1 (en) * 1994-04-21 1995-01-26 Voewa Isoliermaterial Gmbh Web made of heat-insulating material
EP0849164A3 (en) * 1996-12-21 2001-03-07 EADS Airbus GmbH Wall element
FR2817995A1 (en) * 2000-12-08 2002-06-14 Cera Acoustic absorption complex e.g. for vehicle noise has perforated screen to allow passage of sound waves returned by reflective medium
DE10152759B4 (en) * 2001-10-29 2006-03-16 Johnson Controls Gmbh Cladding element for the interior of a vehicle
EP1306205A1 (en) * 2001-10-29 2003-05-02 Johnson Controls GmbH Covering element for the interior of a vehicle and method for fabricating the same
EP1493623A1 (en) * 2003-07-04 2005-01-05 Renault s.a.s. Separation wall between two interior compartments of a vehicle
FR2856967A1 (en) * 2003-07-04 2005-01-07 Renault Sa SEPARATION PANEL OF TWO INNER COMPARTMENTS OF A VEHICLE
EP1654461A2 (en) * 2003-08-07 2006-05-10 BLACK & DECKER INC. Portable air compressor
EP1654461A4 (en) * 2003-08-07 2007-10-10 Black & Decker Inc Portable air compressor
US7762790B2 (en) 2007-02-05 2010-07-27 Black & Decker Inc. Air compressor
GB2461909A (en) * 2008-07-17 2010-01-20 South Bank Univ Entpr Ltd Sound absorbing device
EP2146005A2 (en) * 2008-07-18 2010-01-20 BIG Bau und Immobilienges.m.b.H. Noise protection element
EP2146005A3 (en) * 2008-07-18 2014-01-01 BIG Bau und Immobilienges.m.b.H. Noise protection element
WO2011047429A1 (en) * 2009-10-21 2011-04-28 Bellmax Acoustic Pty Ltd Acoustic panel
CN102639795B (en) * 2009-10-21 2014-09-10 贝尔马克斯声学有限公司 Acoustic panel,wall structure and roadside screen
CN102639795A (en) * 2009-10-21 2012-08-15 贝尔马克斯声学有限公司 Acoustic panel
US8708097B2 (en) 2009-10-21 2014-04-29 Bellmax Acoustic Pty Ltd. Acoustic panel
AU2010310882B2 (en) * 2009-10-21 2011-11-24 Bellmax Acoustic Pty Ltd Acoustic panel
EP2593614A1 (en) * 2010-07-13 2013-05-22 Bellmax Acoustic Pty Ltd An acoustic panel
CN103069086A (en) * 2010-07-13 2013-04-24 贝尔马克斯声学有限公司 An acoustic panel
US8770344B2 (en) 2010-07-13 2014-07-08 Bellmax Acoustic Pty Ltd. Acoustic panel
WO2012006663A1 (en) * 2010-07-13 2012-01-19 Bellmax Acoustic Pty Ltd An acoustic panel
EP2593614A4 (en) * 2010-07-13 2014-12-24 Bellmax Acoustic Pty Ltd An acoustic panel
CN103069086B (en) * 2010-07-13 2015-11-25 贝尔马克斯声学有限公司 Multilayer acoustic panel
WO2013156739A1 (en) * 2012-04-20 2013-10-24 Aircelle Thin panel for absorbing sound waves emitted by a turbofan of an aircraft nacelle, and nacelle provided with such a panel
FR2989814A1 (en) * 2012-04-20 2013-10-25 Aircelle Sa THIN ACOUSTIC WAVE ABSORPTION PANEL EMITTED BY AN AIRCRAFT NACELLE TURBOJET, AND NACELLE EQUIPPED WITH SUCH A PANEL
WO2020136532A1 (en) * 2018-12-26 2020-07-02 3M Innovative Properties Company Acoustic article, acoustic assembly and method of making and using an acoustic article

Also Published As

Publication number Publication date
NO149007C (en) 1986-04-22
DK145310C (en) 1983-03-14
SE402142B (en) 1978-06-19
NO771856L (en) 1977-12-06
FI59134C (en) 1981-06-10
FR2353392B1 (en) 1982-09-17
DK145310B (en) 1982-10-25
NO149007B (en) 1983-10-17
SE7606268L (en) 1977-12-04
DE2724172A1 (en) 1977-12-15
FI771727A (en) 1977-12-04
FR2353392A1 (en) 1977-12-30
FI59134B (en) 1981-02-27
DK241177A (en) 1977-12-04
IT1084993B (en) 1985-05-28

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