High and low frequency sound absorption assembly

Abstract

A sound-absorption assembly comprises a tubular-shaped body having ends closed respectively by first and second microperforated tensioned flexible sheets and at least one planar diaphragm disposed inside the tubular body between the microperforated flexible sheets so as to delimit two spaces between said sheets.

Claims

1. A sound-absorption assembly comprising: a tubular-shaped body having ends closed respectively by first and second microperforated tensioned flexible sheets and at least one low-frequency sound absorbing planar diaphragm disposed inside the tubular body, between the microperforated tensioned flexible sheets, so as to delimit two spaces between said sheets, said diaphragm being configured to be fixed to the body and maintained at a distance from the microperforated tensioned flexible sheets.

2. The sound-absorption assembly according to claim 1, wherein the diaphragm is fixed to the body by means of vibration-damping means.

3. The sound-absorption assembly according to claim 1, wherein said sound-absorption assembly comprises at least one internal flexible sheet interposed between at least one of the microperforated flexible sheets and the diaphragm.

4. The sound-absorption assembly according to claim 3, wherein the internal flexible sheet is microperforated.

5. The sound-absorption assembly according to claim 3, wherein the internal flexible sheet is devoid of perforation.

6. The sound-absorption assembly according to claim 5, wherein said sound-absorption assembly comprises at least one panel of absorbent porous material or materials interposed between at least one of the flexible sheets and the diaphragm.

7. The sound-absorption assembly according to claim 1, wherein said sound-absorption assembly comprises luminous means provided in one of the spaces.

8. The sound-absorption assembly according to claim 7, wherein the diaphragm is a flexible metal plate.

9. The sound-absorption assembly according to claim 8, wherein the metal plate is disposed parallel to the flexible sheets.

10. The sound-absorption assembly according to claim 9, wherein at least one of the flexible sheets is translucent.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Other objects and advantages of the invention will emerge during the following description given with reference to the accompanying drawings, in which:

(2) FIG. 1 depicts a schematic view in cross section of a sound-absorption assembly according to a first embodiment, said assembly being shown mounted on a false ceiling;

(3) FIG. 2 shows a schematic view in cross section of a sound-absorption assembly according to a second embodiment, said assembly being shown mounted on a false ceiling;

(4) FIG. 3 shows a schematic view in cross section of a sound-absorption assembly according to a third embodiment, said assembly being shown mounted on a false ceiling.

(5) For more clarity, the identical or similar elements in the various embodiments are marked by identical reference signs in all the figures.

DETAILED DESCRIPTION

(6) In relation to FIG. 1, a sound-absorption assembly 1 according to a first embodiment is described, said assembly being shown mounted on a false ceiling 50. In order to avoid burdening the figures, the means for fixing the sound-absorption assembly to the false ceiling have not been shown. They may comprise any suitable means known to persons skilled in the art such as for example hangers or more elaborate systems such as those described in the patent application FR 2867797.

(7) The sound-absorption assembly 1 comprises a body 2 with a tubular shape (hereinafter referred to as chamber body 2) closed at its ends respectively by first and second microperforated tensioned flexible sheets 3, 4. End sheets 3, 4 will be spoken of hereinafter. The microperforated sheets 3, 4 are intended to absorb the high-frequency sounds.

(8) In the embodiment described, the chamber body 2 has a parallelepipedal form. It is understood that the chamber body 2 is not limited to this form, it being able to adopt any other form without departing from the scope of the invention. To allow fixing of the end sheets 3, 4, the ends of the chamber body 2 are advantageously provided with fixing means used in a conventional manner for fixing tensioned sheets. According to a particular configuration, provision may be made for the chamber body 2 to be formed by a profiled member or a plurality of abutted profile members, each profiled member forming a rail for receiving the attachment means provided at the peripheral rim of the sheets.

(9) The acoustic-absorption assembly 1 also comprises a planar diaphragm 5 absorbing the low-frequency sound. In the embodiment illustrated, the diaphragm is a flexible metal sheet 5. The latter is disposed inside the tubular body 2, between the end sheets, so as to delimit between said sheets two spaces 6, 7, preferably separate. In other words, the spaces 6, 7 do not communicate with each other. Advantageously, the metal plate 5 is disposed parallel to the end sheets 3, 4.

(10) According to a particularly advantageous embodiment, the metal plate 5 is fixed to the chamber body 2 by means of a fixing system provided with vibration-damping means 30. The damping means consist of one or more parts produced from a flexible material so as to afford the absorption of vibrations between the metal plate 5 when the latter vibrates under the action of acoustic waves and the chamber body 2 supporting said plate. The metal plate 5 can thus vibrate and absorb the known frequencies without the acoustic assembly 1 also vibrating. By way of example, the damping means are Silentblocs.

(11) The metal plate 5 is advantageously situated at equal distances from the end sheets 3, 4.

(12) The acoustic assembly 1 is mounted so as to have one of the end sheets 3, 4 facing the false ceiling 50, the chamber body 2 extending substantially perpendicular to the plane of the false ceiling 50. The acoustic assembly 1 is placed at a certain distance from the false ceiling 50 so as to duplicate the acoustically treated surfaces. This is because, by being placed at a certain distance from the false ceiling 50, the acoustic assembly 1 offers a top surface (corresponding to the end sheet 3) and a bottom surface (corresponding to the end sheet 4), both microperforated, absorbing the high-frequency sounds. So that the acoustic assembly 1 can thus serve as a double acoustic chamber, it is necessary to place the acoustic assembly 1 at a distance of at least 2 centimeters from the false ceiling. Hereinafter, the end sheet closest to the false ceiling 50 will be referred to as the top end sheet 3 and the end sheet situated furthest away from the false ceiling 50 will be referred to as the bottom end sheet 4.

(13) In the embodiment illustrated in FIG. 2, the acoustic absorption assembly 10 repeats all the features of the previously described element.

(14) The acoustic assembly 10 further comprises luminous means 8 provided in the lower space 7 (the space delimited between the metal plate 5 and the bottom metal plate 4). The luminous means 8 are fixed, directly or indirectly, to the bottom face of the metal plate 5, as well as to the partition portion of the chamber body 2 situated under the metal plate 5. It is of course obvious that the invention is not limited to this configuration, the luminous means 8 being able to be provided solely on the metal plate 5 or solely on the partition portion of the chamber body 2.

(15) Advantageously, the acoustic assembly 10 comprises a flexible internal sheet 9 interposed between the bottom metal plate 4 and the metal plate 5. The internal sheet 9 has no perforation. Depending on the illuminating power of the luminous means 8, the internal sheet 9 will be translucent or not. The internal sheet 9 is disposed parallel to the end sheets 3, 4.

(16) The acoustic assembly 10 further comprises a panel of sound-absorbent porous material or materials 11 interposed between the end sheet 3 and the metal plate 5. This thus improves the acoustic insulation. It is of course evident that, if the absorption assembly does not comprise any luminous means, a panel of absorbent porous material or materials 11 could also be provided in the bottom space 7 delimited by the metal plate 5 and the bottom end sheet 4, in replacement for or in addition to the one disposed in the top space 6. Moreover, in the embodiment illustrated, the panel of porous material or materials 11 is formed in a single piece and fills the whole of the top acoustic space. It is of course obvious that the panel of porous material or materials 11 could be formed by a plurality of layers of the same or different porous materials and could also have smaller dimensions, in particular in order to limit the weight of the acoustic assembly.

(17) In the embodiment illustrated in FIG. 3, the sound-absorption assembly 20 repeats all the features of the element described with reference to FIG. 1.

(18) The sound-absorption assembly 20 further comprises two microperforated flexible internal sheets 12, 13, interposed between the bottom end sheet 4 and the metal plate 5. The internal sheets 12, 13 are disposed parallel to each other and to the metal plate 5. In order to improve the sound insulation, two panels of sound-absorbent porous material or materials 11, 14, one being interposed between the metal plate 5 and the adjacent internal layer 12, the other being interposed between the metal plate 5 and the top end sheet 3. It is of course obvious that the invention is not limited to this configuration. A sound-absorption assembly comprising only one or more than two acoustic (ie microperforated) internal sheets 12, 13 may be provided, these being able to be placed in one or other or both spaces 6, 7 delimited by the metal plate 5. Moreover, the absorption assembly 20 may be provided without a panel of absorbent porous material or materials or with only one, in this case disposed either in the top space 6 or in the bottom space 7. Moreover, in the embodiment illustrated, the panels of absorbent porous material or materials 11, 12 are formed in a single piece and fill all the acoustic spaces. It is of course obvious that the panels 11, 12 could be formed by a plurality of layers of the same or different absorbent material or materials and could also have smaller dimensions, in particular in order to limit the weight of the acoustic assembly.

(19) In the embodiments described, the end sheets 3, 4 are shown disposed so as to lie in a plane containing the end edges 21, 22, 23, 24 of the chamber body 2. Provision may also be made for these end layers to be disposed at the ends of the chamber body 2 but in a plane slightly offset with respect to the plane passing through the end edges 21, 22, 23, 24 of the chamber body 2.

(20) Moreover, in the embodiments previously described, the diaphragm chosen is a metal plate. It is of course obvious that the above description also applies to diaphragms other than a metal plate.

(21) In the previously described embodiments, the false partition facing which the acoustic assembly is placed is a false ceiling, the assembly then forming an assembly suspended horizontally. It is of course obvious that the false partition facing which the acoustic assembly is placed may also be a wall, the acoustic assembly then forming an assembly suspended vertically. According to a particular embodiment, an acoustic assembly arranged so as to have one part intended to be placed facing the ceiling and another part placed facing a wall, the acoustic assembly then forming a horizontally and vertically suspended assembly, may also be provided.

(22) Though the mounting of a single acoustic assembly on a false partition is described above, it will be understood clearly that an installation in which the false partition is equipped with a plurality of acoustic assemblies may be provided.

(23) Moreover, in the embodiments described above, the acoustic assembly is associated with a false partition, and in this case a false ceiling. It is of course obvious that the acoustic assembly according to the invention could also be used directly on a ceiling or wall.

(24) The invention is described above by way of example. Naturally a person skilled in the art is in a position to implement different variant embodiments of the invention without departing from the scope of the invention.