WO2012059899A2

WO2012059899A2 - Acoustic panel and acoustic enclosure

Info

Publication number: WO2012059899A2
Application number: PCT/IB2011/054949
Authority: WO
Inventors: Joan Rivas Delgado; Jesús URIOL CHAVARRIGA
Original assignee: Alims 2000, S. L.
Priority date: 2010-11-05
Filing date: 2011-11-07
Publication date: 2012-05-10
Also published as: ES2391336B1; ES2421461R1; ES2421461B1; ES2391336A1; ES2421461A2; WO2012059899A3

Abstract

It comprises a plurality of grooves (2, 2A, 2B, 2C, 2D) at the frontal face (1a) and a plurality of grooves (3, 3A, 3B, 3C, 3D) at the rear face (1b), the grooves (3, 3A, 3B, 3C, 3D) of the rear face (1b) determining a plurality of perforations (4, 4A, 4B) in the panel (1), in the intersection areas with the grooves (2) of the frontal face (1a), characterized in that: said grooves (2, 2A, 2B, 2C, 2D) of the frontal face (1a) have a width from 2 and 6 mm, a depth from 5 and 11 mm, and they are spaced a distance from 9 and 14 mm, and said grooves (3, 3A, 3B, 3C, 3D) of the rear face (1b) have a width from 8 and 12 mm and a depth from 5 and 11 mm, and in that: the intersection area of the grooves (3, 3A, 3B, 3C, 3D) of the rear face (1b) with the grooves (2, 2A, 2B, 2C, 2D) of the frontal face (1a) determines a perforation rate of the panel (1) equal or lower than 15%, each of the grooves (3, 3A, 3B, 3C, 3D) of the rear face (1b) having a percentage of perforation-free surface equal or higher than 75%, so that said grooves (3, 3A, 3B, 3C, 3D) of the rear face (1b) configure sound absorbing cavities (5, 5B) in the panel (1, 1A, 1B, 1C, 1D) itself.

Description

ACOUSTIC PANEL AND ACOUSTIC ENCLOSURE

The present invention refers to a absorbent acoustic panel and to an acoustic enclosure comprising said acoustic panel.

BACKGROUND OF THE INVENTION

Acoustic panels comprising a plurality of perforations for absorbing sound, which extend from the visible face of the panels to the rear face, are known. These panels are mounted on support profiles fixed to ceilings or walls, determining an air chamber that houses behind the panel an absorbent material, such as rock wool.

The coefficient of acoustic absorption of the panel changes according to the perforation percentage, this coefficient being higher when the perforated surface of the profile is greater.

The current acoustic enclosures including absorbent acoustic panels such as those described require the presence of an air chamber to obtain an acceptable coefficient of acoustic absorption.

However, the provision of said air chamber has the drawback that it involves a loss of useful space of the site where the acoustic enclosure is done.

On the other hand, the fixation of the panels to said acoustic panels is laborious, because it must be done preventing the blocking of the perforations by the support profiles to decrease the acoustic efficiency.

Furthermore, when the desired degree of acoustic absorption is high, it is necessary to resort to panels with high perforation rates, which makes the panel very fragible . DESCRIPTION OF THE INVENTION The object of the present invention is to solve said drawbacks, developing an acoustic panel and closure presenting the advantages that will be described hereinafter .

According to this objective, according to a first aspect of the present invention, an absorbent acoustic panel comprising a plurality of grooves at the frontal face and a plurality of grooves at the rear face is provided, the grooves of the rear face determining a plurality of perforations in the panel, in the intersection areas with the grooves of the frontal face, being characterised in that:

- said grooves of the frontal face have a width from 2 and 6 mm, a depth from 5 and 11 mm, and they are separated a distance from 9 and 14 mm, and

- said grooves of the rear face have a width from 8 and 12 mm and a depth from 5 and 11 m,

and in that :

- the intersection area of the grooves of the rear face with the grooves of the frontal face determines a perforation ratio of the panel equal to or lower than 15%, each of the grooves of the rear face having a percentage of perforation-free surface equal to or higher than 75%, so that said grooves of the rear face configure sound absorbing cavities in the panel itself.

Surprisingly, it has been observed that the non- perforated area of the grooves of the rear face of the panel determines cavities in the panel itself that provide absorbent properties. Thanks to this fact, it is obtained a very effective panel from an acoustic point of view not resorting to a high perforation ration, so that the panel is also very resistant and it can be made quickly.

Another advantage of the claimed acoustic panel is that it can be fixed directly on support profiles not losing acoustic efficiency, because the presence of said absorbent cavities compensates the absorption loss caused when some of the perforations of the panel are blocked with the support profile.

According to the same object, according to a second aspect, the present invention provides an acoustic enclosure with no air chamber including the claimed panel .

Surprisingly, it has been observed that the acoustic panel of the present invention guarantees a good acoustic absorption with no air chamber, so that said panel can be mounted directly on a wall or ceiling not losing any acoustic efficiency.

Thanks to this feature, an acoustic closure with no air chamber is provided, which is very useful to be installed in sites of reduced dimensions in which currently it was not possible to install any acoustic closure. Furthermore, the claimed closure has the advantage that it can be adapted to light movable structures that can be placed on different places of a room or lounge to enhance its acoustics.

According to a preferred embodiment, preferably the grooves on the rear face have a perforation-free surface equals or greater than 82% and, advantageously, the grooves of the rear and frontal face longitudinally extend in the panel, in a aligned way, keeping or not a parallel relation to each other.

According to the same preferred embodiment, advantageously, the grooves of the rear face of the panel longitudinally extend with a sinusoidal wave shape.

It has been observed that the grooves with a sinusoidal wave shape permit to configure absorption cavities in the panel which are very efficient from an acoustic point of view.

Advantageously, said sinusoidal waves are continuous. However, alternatively, said sinusoidal waves can be discontinuous. Therefore, the panel has an increased resistance.

Preferably, said grooves with sinusoidal wave shape are placed substantially parallel and separated to each other a distance (x) from 35 mm and 70 mm, this distance (x) being the distance between sinus or crests of two contiguous waves.

Again preferably, said sinusoidal waves have a wave length from 30 mm and 50 mm, and a wave width from 40 mm and 60 mm.

Advantageously, the depth of the grooves of the rear face changes along the length of the panel inversely to the depth of the grooves of the frontal face, so that inside the panel a waved medium plane "z" is created, the intersection area of both grooves defining the perforations being placed in said waved plane "z".

It has been observed that, as the intersection are of both grooves is placed in said waved medium plane, the panel perforations defined by said intersection area are placed at different heights, which enhances substantially the acoustic efficiency of said panel, increasing this way the absorption at medium frequencies very necessary for correcting the human speech.

Preferably, said panel comprises at least two longitudinal sections , each provided with a waved medium plane "zl, z2", the waving direction of each of said planes being inverted.

According to an embodiment, the transversal section of the grooves of the frontal face includes a bottom "d" with a width higher than the input hole "e".

It has been observed that the higher width bottom "d" permits to increase the perforation ratio of the panel, because the internal intersection area of the frontal face with the grooves of the rear face is increased, and therefore, the area of the perforations of the panel itself. Therefore, it is possible to increase the perforation ratio of the panel not changing substantially its aesthetical appearance.

Also advantageously, the grooves of the frontal face are made in a fire-proof material layer, preferably a material including magnesium.

BRIEF DESCRIPTION OF THE DRAWINGS For a better understanding of what has been described, some drawings are attached in which, diagrammatically and only as a non-limitative example, some practical embodiments are shown.

In said drawings,

Fig. 1 shows a plan view of a first embodiment of the acoustic panel of the frontal face including frontal grooves .

Fig. 2 shows a plan view of the acoustic panel of Fig. 1 of the rear face including rear grooves with a sinusoidal wave shape.

Fig. 3 shows a section of Fig. 1.

Fig. 4 shows a perspective view of the panel of Fig. 1 of its rear face.

Fig. 5 shows a perspective view of the panel of Fig. 1 of its frontal face.

Fig. 6 shows a plan view of an embodiment of the panel of Fig. 1 including rear grooves with a discontinued sinusoidal wave shape.

Fig. 7 is a graphical representation of the practical acoustic absorption coefficient according to the sound frequency applied to an acoustic enclosure with air chamber, including the panels of the embodiment of Figs. 1 to 5.

Fig. 8 is a graphical representation of the practical acoustic absorption coefficient according to the sound frequency applied to an acoustic enclosure with no air chamber, including the panels of the embodiment of Figs. 1 to 5.

Fig. 9 shows a cross section analogous to that of Fig. 3 of a second embodiment of the panel. This Fig. 9 includes a detail showing the cross section of the frontal grooves .

Fig. 10 shows a plan view of a third embodiment of the panel in which the depth of the grooves changes along the length of the panel.

Figs. 11 and 12 show two longitudinal sections of the panel of Fig. 10.

Fig. 13 shows a plan view of a fourth embodiment of the panel provided with non-parallel frontal grooves.

Fig. 14 shows a plan view of the embodiment of

Fig. 13 of its frontal face of sinusoidal waves.

Fig. 15 shows a plan view of a fifth embodiment of the panel provided with circular grooves.

Fig. 16 shows a plan view of the embodiment of Fig. 15 of its frontal face of sinusoidal waves.

DESCRIPTION OF SEVERAL PREFERRED EMBODIMENTS

Now several embodiments of the panel of the present invention are described, including grooves 3, 3A, 3B, 3C, 3D at the rear face with a sinusoidal wave shape.

As the drawings show, the panel 1, 1A, IB, 1C, ID of the present invention includes a plurality of frontal grooves 2, 2A, 2B, 2D extending at the frontal face la, and a plurality of rear grooves 3, 3A, 3B, 3C, 3D extending also at the rear face lb of the panel 1, 1A, IB, 1C, ID, with a sinusoidal wave shape.

The intersection areas of the rear grooves 3, 3A, 3B, 3C, 3D with the frontal grooves 2, 2A, 2B, 2C, 2D determines a plurality of perforations 4, 4A, 4B provided for the absorption of the acoustic energy.

However, as described, in the panel 1, 1A, IB, 1C, ID of the present invention the perforated area is never higher than 15% of the whole surface of the panel 1, 1A, IB, 1C, ID, each of the grooves 3, 3A, 3B, 3C, 3D of the rear face having a percentage of free-perforation surface equal or higher than 75%, so that said grooves of the rear face configure cavities 5, 5B for the absorption of sound in the panel itself.

Thanks to this feature, the panel 1, 1A, IB, 1C,

ID of the present invention is very efficient from the acoustic point of view with no need of providing a high perforation ratio, so that it is very resistant and it can be manufactured quickly.

Another advantage of the panel 1, 1A, IB, 1C, ID of the present invention is the fact that it guarantees a good acoustic absorption with no need for an air chamber, so that said panel 1, 1A, IB, 1C, ID can be mounted directly on a wall or ceiling not losing any efficiency.

Thanks to this feature, an acoustic enclosure with no air chamber is provided, being very useful for being installed in sites of reduced dimensions in which currently it is not possible to install any acoustic enclosure .

Hereinafter an acoustic absorption comparative test in a reverberant room according to standard UNE-EN ISO 354:2004 is described, from a sample of panels 1 of the present invention mounted with and without air chamber .

In this test, the panels 1 comprise an agglomerated table of medium density fibers (DM) with a thickness of 16 mm, covered with a bamboo plate of 1 mm at its frontal face and an auto-adhesive black veil of glass fiber at its rear face.

The tested panels are those shown in attached Figs. 1-5. These panels 1 have frontal grooves 2 with a width of 3.2 mm and a depth of 9 mm, which are spaced to each other a distance of 11.7 mm. The rear grooves 3, with a continue wave shape, have a width and a depth of 8 mm, a wave length of 43.3 mm, a wave amplitude of 49.6 mm, and they are spaced to each other a distance of 38 mm, this distance being the distance (x) between sinus and crests of two contiguous waves. The perforation ratio of the tested panels 1 is 10%, the rear grooves 3 having a percentage of free-perforation surface of 76%.

The panels 1 are mounted on wood strips of 40 mm creating the space enough to house rock wool of the same thickness and density of about 40 Kg/m³.

The test has been done with the panels 1 mounted according two different configurations:

- Directly on a reflecting surface with a mineral wool layer with a thickness of 40 mm (test without air chamber) .

- With an air chamber with a depth of 40 cm with a mineral wool layer with a thickness of 40 mm (test with air chamber) .

In the test without air chamber, the panels 1 have been placed directly on the floor of the test room sealing the sides of the whole sample by a wood reflecting perimeter frame, to prevent the passage of acoustic energy through the sides of the sample and acting only the upper face .

In the test with air chamber, the panels 1 have been placed on supports to create a chamber with 40 cm of depth from the rock wool and the floor of test room. The sides of the sample have also been sealed by a wood reflecting perimeter frame to prevent the passage of acoustic energy through the sides of the sample and acting only at the upper face.

The measures done have permitted to calculate the practical acoustic absorption coefficient ° _p and the weighted acoustic absorption coefficient ° _w of the panels 1, and also to assign a class of acoustic absorption to the panels 1 (see the attached results and Figs . 7 and 8 ) .

TEST RESULTS WITH CHAMBER

Practical acoustic absorption coefficient, °

Frequency (Hz) ^KP

125 0.60

250 0.75

500 0.80

1000 0.90

2000 0.85

4000 0.75

Weighted sound absorption 0.85

coefficient (oc_w)

Shape -

Class o _w B (0.80-0.85)

TEST RESULTS WITHOUT CHAMBER

Frequency (Hz) ^KP

125 0.20

250 0.55

500 0.95

1000 0.95

2000 0.70

4000 0.65

Weighted sound absorption 0.75 coefficient ( oc_w )

Shape -

Class o _w C (0.60-0.75)

The practical sound absorption coefficient is a value that depends on the sound frequency, based in the measurements by bands of one-third of octave according to standard ISO 354. Regarding the weighted sound absorption coefficient, it is a single value independent from the frequency, which is the same as the value of the reference curve at 500 Hz after moving it to the curve of practical sound absorption values. This weighted sound absorption value is used to calculate the acoustic absorption class.

From the analysis of the results and drawings it can be seen that the weighted acoustic absorption coefficients are higher than 0.70 in the two tests; specifically 0.75 in the test without chamber and 0.85 in the test with chamber. It can also be seen that, in the frequency bands of 500 Hz and 1000 Hz, the practical absorption coefficients are higher than 0.80, in both the tests with and without chamber.

From the results it can be determined that the panels of the present invention guarantee an excellent acoustic efficiency mounted with or without air chamber, and said efficiency is particularly relevant in very significant frequency bands, such as human speech.

Thanks to this feature, the panels of the present invention are useful to be installed in sites with reduced dimensions, in which it is now not possible to install an acoustic enclosure because there is no space to provide an air chamber.

On the other hand, in both cases, the acoustic panels 1 have a perforation ratio lower than 15%, so that the acoustic efficiency is obtained not affecting the general resistance of the panels 1. Furthermore, the panels 1 can be manufactures very easily and quickly, because the rear grooves 3 can be mechanized by milling.

With reference to Fig. 9, this drawing shows an embodiment of the panel 1A in which the cross section of the grooves 2A of the frontal face includes a bottom "d" with a width higher than the input hole "e". Specifically, in the embodiment shown in Fig. 9, the width of the bottom "d" is 5 mm and the with of the hole "e" is 3 mm.

As stated previously in the summary of the invention, this embodiment has the advantage with respect to the embodiment shown in Fig. 3 that permits to increase the perforated area of the panel 1A, and therefore its perforation rate and acoustic efficiency, not changing substantially its aesthetic shape.

Figs. 10, 11 and 12 show a third embodiment of the panel IB provided with two longitudinal sections in which the depth of the grooves 3B of the rear face change along the length of the panel IB inversely to the depth of the grooves 2B of the frontal face, so that inside the panel IB two waved medium planes "zl, z2" are created with different waving directions.

As shown in the sections of Figs. 11 and 12, the intersection area of both grooves 2B, 3B is placed in the waving planes "zl, z2", so that the perforations of the panel IB defined by said intersection area are placed at different heights. Thanks to this feature, the acoustic efficiency of the claimed panel IB is even higher.

Figs. 13-16 show two further embodiments of the panel 1C, ID constituting two design variations keeping the same features of acoustic efficiency than the panels of the previous embodiments.

In the embodiment of Figs. 13 and 14, the grooves 2C of the frontal face and the grooves 3C of the rear face are kept aligned in the same direction. However, as shown in the same drawings, said grooves 2C, 3C are not parallel. This design is suitable to create circular shape structures like a dome.

In the embodiment of Figs. 15 and 16, the frontal grooves 2D and the sinusoidal grooves 3D are circular.

Even though some specific embodiments of the present invention have been described and shown, it is clear for a person skilled in the art that variations and modifications can be done, or the details can be substituted by other technically equivalent ones, without departing from the scope of protection defined by the attached claims.

E.g. even though reference is made in the present specification to panels 1, 1A, IB, 1C, ID with frontal grooves 2, 2A, 2B, 2C, 2D which are substantially equidistant to each other, the same grooves could not be equidistant and they could be spaced to each other changing distances. Similarly, even though embodiments with rear grooves 3, 3A, 3B, 3C, 3D with a sinusoidal wave shape have been described, the same results could be obtained with grooves of similar dimensions with other shapes. Similarly, even though that for the tests panels 1 comprising an agglomerated table covered with a bamboo plate at its frontal face have been used, the same acoustic results could be obtained with tables covered by plates including fire-proof material, such as e.g. magnesium.

Claims

1. Absorbing acoustic panel (1, 1A, IB, 1C, ID) comprising a plurality of grooves (2, 2A, 2B, 2C, 2D) at the frontal face (la) and a plurality of grooves (3, 3A, 3B, 3C, 3D) at the rear face (lb), the grooves (3, 3A, 3B, 3C, 3D) of the rear face (lb) determining a plurality of perforations (4, 4A, 4B) in the panel (1), in the intersection areas with the grooves (2) of the frontal face (la), characterized in that:

- said grooves (2, 2A, 2B, 2C, 2D) of the frontal face (la) have a width from 2 and 6 mm, a depth from 5 and 11 mm, and they are spaced a distance from 9 and 14 mm, and

- said grooves (3, 3A, 3B, 3C, 3D) of the rear face (lb) have a width from 8 and 12 mm and a depth from 5 and 11 mm,

and in that :

- the intersection area of the grooves (3, 3A, 3B, 3C, 3D) of the rear face (lb) with the grooves (2, 2A, 2B,

2C, 2D) of the frontal face (la) determines a perforation rate of the panel (1) equal or lower than 15%, each of the grooves (3, 3A, 3B, 3C, 3D) of the rear face (lb) having a percentage of perforation-free surface equal or higher than 75%, so that said grooves (3, 3A, 3B, 3C, 3D) of the rear face (lb) configure sound absorbing cavities (5, 5B) in the panel (1, 1A, IB, 1C, ID) itself.

2. Panel according to claim 1, wherein said grooves (3, 3A, 3B, 3C, 3D) of the rear face (lb) extend longitudinally in the rear face (lb) of the panel (1, 1A, IB, 1C, ID) with a sinusoidal wave shape.

3. Panel according to claim 2, wherein said sinusoidal waves are continue.

4. Panel according to claim 2, wherein said sinusoidal waves are discontinue.

5. Panel according to anyone of claims 2-4, wherein said grooves (3, 3A, 3B, 3D) with a sinusoidal wave shape are placed substantially parallel and spaced to each other a distance (x) from 35 mm and 70 mm, this distance (x) being the distance between sinus or crests of two contiguous waves.

6. Panel according to anyone of claims 2-5, wherein the sinusoidal waves determining said grooves (3, 3A, 3B, 3C, 3D) have a wave length from 30 mm and 50 mm and a wave amplitude from 40 mm and 60 mm.

7. Panel according to anyone of the previous claims, wherein the depth of the grooves (3B) of the rear face (lb) changes along the length of the panel (IB) inversely to the depth of the grooves (2B) of the frontal face (la), so that a waving medium plane (z) is created inside the panel, the intersection area of both grooves (2B, 3B) defining the perforations (4B) being placed in said waving plane (z) .

8. Panel according to claim 7, comprising at least two longitudinal sections, each provided with a waving medium plane (zl, z2), the waving direction of each of said planes being inverted.

9. Panel according to anyone of the previous claims, wherein the cross section of said grooves (2A) of the frontal face (la) includes a bottom (d) with a width higher than an input hole (e) .

10. Panel according to anyone of the previous claims, wherein the grooves (2) of the frontal face (la) are done in a fire-proof material layer, preferably a material including magnesium.

11. Acoustic enclosure comprising an acoustic panel (1, 1A, IB, 1C, ID) according to anyone of the previous claims, characterized in that it has no air chamber .

12. Enclosure according to claim 11, comprising an absorbent acoustic material between said acoustic panel (1, 1A, IB, 1C, ID) and a wall or ceiling on which the acoustic panel (1, 1A, IB, 1C, ID) is mounted.