EP4223952A1

EP4223952A1 - Sound-absorbing panel with integrated self-supporting frame

Info

Publication number: EP4223952A1
Application number: EP23154166.5A
Authority: EP
Inventors: Giorgio CELLERINO
Original assignee: Sts Isolamenti Srl
Current assignee: Sts Isolamenti Srl
Priority date: 2022-02-04
Filing date: 2023-01-31
Publication date: 2023-08-09
Also published as: IT202200001994A1

Abstract

A sound-absorbing panel (1) is described comprising a layer of sound-absorbing material (4) and an integrated self-supporting frame (5) supporting the layer of sound-absorbing material (4), wherein the layer of sound-absorbing material (4) has a front surface (6) apt to be directly exposed to an acoustic source (7) for being struck by sound waves (3) without the interposition of grated elements or other parts, a rear surface (8) opposite the front surface (6), and a lateral surface (10) delimited between the front surface (6) and the rear surface (8); wherein the self-supporting frame (5) comprises: a support profile (11) laterally surrounding at least part of the layer of sound-absorbing material (4) and defining an abutment body for the lateral surface (10) of the layer of sound-absorbing material (4) itself; a protective sheet (12) fixed to the support profile (11) and defining an abutment element for said rear surface (8) of the layer of sound-absorbing material (4); and at least one containment bracket (13) having a first fixing portion (13a) fixed to the support profile (11) and a second containment portion (13b) cooperating with the layer of sound-absorbing material (4) at the front surface (6); wherein the sound-absorbing material is made of natural or artificial resin-bonded fibres; and wherein the layer of sound-absorbing material (4) is releasably interposed and fitted between the second containment portion (13b) and the protective sheet (12).

Description

CROSS-REFERENCE TO RELATED APPLICATIONS

This patent application claims priority from Italian Patent Application no. 102022000001994 filed on February 4, 2022 , the entire disclosure of which is incorporated herein by reference.

TECHNICAL FIELD

The present invention relates to a sound-absorbing panel with an integrated self-supporting frame, in particular a sound-absorbing panel for use in acoustic barriers for machinery, or in any case in acoustic barriers intended to be arranged in an external environment.

STATE OF THE ART

Sound-absorbing panels are known to include one or more layers of rock wool as a sound-absorbing material.
Although the excellent sound insulation properties provided by rock wool are well known, it is also known that this material suffers relatively rapid deterioration and degradation when exposed to weathering.
In particular, rock wool tends to absorb moisture, which first causes the layer to swell and then progressively flake or fray.
In order to limit the above deterioration, it is known to cover the rock wool layer with two sheets, usually made of metal.
For example, this measure is widely used in the case of acoustic barriers for machinery intended to be arranged in an external environment, which are made up of a series of panels of the type mentioned above, which are exposed to weathering.
More precisely, a panel of the type mentioned above includes:

a first front sheet fixed to the surface of the sound-absorbing material suitable to be directly exposed to the sound source, i.e., directly struck or hit by the sound waves; and
a second rear sheet fixed to the opposite surface of the sound-absorbing material.

In practice, the front sheet faces the machine to be acoustically insulated and the rear sheet faces the opposite side.
Typically, each sheet is glued or nailed or riveted to the rock wool at its respective surface.
Conveniently, the front sheet is perforated, for example with a 35% void-to-full ratio, in order to allow the sound waves to strike the rock wool with the interposition of the front sheet itself.
In practice, the front sheet defines a grated element to protect the sound-absorbing layer. In fact, the grated element limits the deterioration of the rock wool.
This increases the service life of the sound-absorbing material.
However, the Applicant observed a significant decrease in the sound-absorbing properties of the panel thus made, precisely because of the presence of the perforated sheet.
In addition, since this sheet is glued or nailed or riveted to the rock wool, the maintenance of the panel, i.e., the replacement of this sound-absorbing layer, is somewhat difficult.
The Applicant also noted that the glue or the fixing means, such as nails or rivets, reduce the sound insulation properties of the panel.
Finally, each panel thus obtained requires supporting structures so that it can be arranged in series with other panels to form the acoustic barrier. These supporting structures are usually added at a later stage, i.e., when assembling the acoustic barrier, often fixing them to the respective sheet in arbitrary positions and without regard to the structure of the underlying sound-absorbing layer. This further decreases the acoustic performance of the sound-absorbing material.

OBJECT AND SUMMARY OF THE INVENTION

The object of the present invention is to provide a sound-absorbing panel, which is highly reliable and cost-effective, and allows at least some of the above-mentioned drawbacks related to sound-absorbing panels of the known type to be obviated.
According to the invention, this object is achieved by means of a sound-absorbing panel as claimed in claim 1.

BRIEF DESCRIPTION OF THE DRAWINGS

For a better understanding of the present invention, a preferred, non-limiting embodiment thereof will be described below purely by way of example and with the aid of the accompanying drawings, wherein:

Figure 1 is a perspective view, with parts removed for clarity, of an acoustic barrier comprising a series of sound-absorbing panels made according to the present invention;
Figure 2 is a sectional side view in enlarged scale and with parts removed for clarity of one of the sound-absorbing panels in Figure 1; and
Figure 3 is a rear view in enlarged scale and with parts removed for clarity of one of the sound-absorbing panels in Figure 1.

DETAILED DESCRIPTION

With reference to the accompanying drawings, the reference numeral 1 indicates, as a whole, a sound-absorbing panel, in particular a sound-absorbing panel 1 for use in acoustic barriers for machinery, or in any case in acoustic barriers intended to be arranged in an external environment, to which the present description will make explicit reference without thereby losing generality.
As can be seen in Figure 1, the panel 1 is advantageously used for the construction of an acoustic barrier 2 of the modular type, in which each module is precisely defined by a panel 1, due to the peculiar configuration of the panel 1 itself according to the present invention, which will be explained in detail below.
Preferably, the acoustic barrier 2 is of the type used to shield or absorb or dampen sound waves 3 emitted by a machine.
Alternatively, the acoustic barrier 2 can be used to shield or dampen sound waves 3 coming from vehicle traffic on a road.
Alternatively, the acoustic barrier 2 can be used to shield sound waves 3 coming from any acoustic source. For example, a series of panels 1 according to the present invention could be organized as a "closed box", so that the acoustic barrier 2 defines a soundproof cabin.
According to the preferred embodiment described and illustrated herein, each panel 1 is suitable to be arranged in the external environment and thus exposed to weathering.
In one embodiment, the acoustic barrier 2 is arranged in an internal environment.
As can be seen in detail in Figure 2, the sound-absorbing panel 1 according to the present invention comprises a layer of sound-absorbing material 4 and, according to an important aspect of the present invention, an integrated self-supporting frame 5 supporting the layer of sound-absorbing material 4.
In detail, the layer of sound-absorbing material 4 has:

a first surface or front surface 6 designed to face an acoustic source 7 (for example a machine, as schematically shown in Figure 1) so as to be struck by sound waves 3 coming from the latter;
a second surface or rear surface 8 opposite the front surface 6; and
a third surface or lateral surface 10 delimited between the front surface 6 and the rear surface 8.

In greater detail, the layer of sound-absorbing material 4 is defined by one or more rectangular mats (thin parallelepipeds), which are preferably substantially smooth.
Alternatively, the layer of sound-absorbing material 4 may have any other shape (triangular, circular, polygonal, curved, regular or irregular) to suit the type of acoustic barrier 2 to be made and/or may include embossing or other surface machining.
According to a first aspect of the present invention, the sound-absorbing material of the layer 2 is made of natural or artificial resin-bonded fibres, and therefore different from rock wool.
Consequently, the front surface 6 is designed to be directly exposed to the acoustic source 7 so as to be directly struck by sound waves 3, without the interposition of grated elements or other parts.
According to a further aspect of the present invention, the frame 5 comprises:

a support profile 11 laterally surrounding at least part of the, in particular the whole, layer of sound-absorbing material 4 and defining an abutment body for the lateral surface 10 of the layer of sound-absorbing material 4 itself;
a protective sheet 12 fixed to the profile 11 and defining an abutment element for the rear surface 8 of the layer of sound-absorbing material 4; and
at least one containment bracket 13 having a first fixing portion 13a fixed to the profile 11 and a second containment portion 13b cooperating with the layer of sound-absorbing material 4 at the front surface 6.

According to the invention, the layer of sound-absorbing material 4 is releasably interposed and fitted between the second containment portion 13b and the protective sheet 12.
Preferably, the profile 11 is defined by a hollow tubular (box-shaped) element laterally surrounding the layer of sound-absorbing material 4.
Conveniently, the containment bracket 13 has an L-shaped profile, in which the first portion 13a defines a first wing of the L-shaped profile and the second portion 13b defines a second wing of the L-shaped profile.
Advantageously, this second wing is configured to cooperate exclusively with a peripheral portion 6a of the front surface 6 of the layer of sound-absorbing material 4 to push the layer of sound-absorbing material 4 itself against the protective sheet 12, while leaving almost the entire front surface 6 free.
In this way, the bracket 13 keeps the layer 4 in place without constituting an obstacle for the sound waves 3, which can strike the front surface 6 directly, without the interposition of parts.
Conveniently, the bracket 13 is fixed to the profile 11 by threaded members (known per se).
According to this preferred embodiment, the protective sheet 12 is fixed to the profile 11 by threaded members (known per se).
Preferably, the sound-absorbing material comprises natural resin-bonded fibres or natural fibres immersed in a resin matrix, the natural fibres being made of cotton fibres.
More preferably, the sound-absorbing material is defined by a resin-bonded cotton lint comprising 750 cotton and 25% resin.
The resin is preferably phenolic or epoxy resin.
Due to the combined synergistic effect given by the presence of the frame 5 according to the configuration described above and by the nature of the sound-absorbing material, it is possible to obtain a sound-absorbing panel 1 with improved acoustic performance compared to known sound-absorbing panels, as no grated element is required to protect the sound-absorbing material, which is also easy to mount, maintain and assemble with other panels 1.
In fact, the profile 11 defines an outer perimetral edge 14 of the sound-absorbing panel 1 itself, against which the lateral surface 10 of the layer 4 abuts (Figure 2).
The perimetral edge 14, i.e., the tubular element defined by the profile 11, is advantageously configured to be releasably fixed to the perimetral edge 14 of another sound-absorbing panel 1 to define the aforesaid modular acoustic barrier 2, in which each module is defined by one said sound-absorbing panel 1.
In the example described, the panel 1 is substantially rectangular in shape, therefore the outer perimetral edge 14 defined by the profile 11 comprises two long sides and two short sides.
Preferably, the profile 11 comprises, in addition to the perimetral edge 14, a few partitions 15 (Figures 1 and 3), two in the illustrated case, which are transversal, in particular orthogonal, to the aforesaid long sides and parallel to the aforesaid short sides.
As a result, the layer of sound-absorbing material 4 is divided into a plurality of sectors, three in the illustrated case, rather than consisting of a single sound-absorbing body.
This improves the stability and resistance of the panel 1, while also increasing the stiffness thereof and therefore the acoustic performance.
Conveniently, the layer of sound-absorbing material 4 comprises a further layer of non-woven polyester fabric (not shown) that covers the sound-absorbing material.
In this case, the layer of non-woven fabric defines the front surface 6 designed to be directly exposed to the acoustic source 7.
The Applicant noted, through an extensive experimental campaign, that the presence of the additional layer of non-woven fabric further improves the sound-absorbing properties of the panel 1.
In an alternative embodiment, the sound-absorbing material comprises artificial resin-bonded fibres or artificial fibres immersed in a resin matrix, the artificial fibres being made of polyester fibres.
The Applicant noted that this type of fibre further increases the resistance of the sound-absorbing material to weathering, making the panel 1 particularly suitable for outdoor use.
Advantageously, the sound-absorbing panel 1 further comprises a layer of damping material 16 interposed between the protective sheet 12 and the rear surface 8 of the layer of sound-absorbing material 4 and is formed by a polymer-plastic-based bituminized element.
In practice, the layer of damping material 16 defines a layer of sound-deadening material for the panel 1, the which layer increases the overall stiffness of the panel 1, thus improving its sound-absorbing performance.
Conveniently, the protective sheet 12 is made of ferromagnetic metallic material. Accordingly, a magnetic powder configured to interact magnetically with the protective sheet 12 is dispersed in the layer of damping material 16.
In this way, adhesion between the layer of damping material 16 and the protective sheet 12 is facilitated, resulting in improved structural stability of the panel 1.
The protective sheet 12 has an internal surface 17 facing the layer of sound-absorbing material 4 and an external surface 18 opposite to the internal surface 17.
Advantageously, the protective sheet 12 has two ribs 19 obtained on the external surface 18, which intersect one another at a central point to define a diamond-point camber of the protective sheet 12 itself at said external surface 18, and outwards.
In the illustrated case, the layer of sound-absorbing material 4 being divided into three sectors separated from each other by the aforementioned partitions 15, the panel 1 comprises three protective sheets 12, each of which has two so-called ribs 19, as shown in Figure 3.
The presence of the diamond-point camber allows the stiffness of the protective sheet 12 to be increased, and therefore, the acoustic performance of the panel 1 is further improved.
The advantages enabled by the sound-absorbing panel 1 manufactured according to the present invention will be apparent from an examination of the features thereof.
In particular, due to the combined synergistic effect given by the presence of the frame 5 according to the configuration described above and to the particular sound-absorbing material, it is possible to obtain a panel 1 whose service life is increased and whose acoustic performance is better than that of known sound-absorbing panels.
This means less maintenance and, in any case, easier maintenance operations: it shall suffice to disassemble the bracket 13, thus releasing the layer of sound-absorbing material 4 and replacing it with a new layer 4.
The absence of rigid couplings between the frame 5 and the layer of sound-absorbing material 4, as in the case of the known panels made of rock wool covered with a glued or nailed or riveted sheet, also facilitates a reuse of the frame 5, which is more difficult in the previous case.
In addition, the absence of glue or fixing means further increases the sound insulation properties of the panel 1 according to the invention.
Lastly, the panel 1 according to the invention, in order to be mounted with other panels 1 to form an acoustic barrier 2, does not require any supporting structure: the presence of the integrated self-supporting frame 5, in fact, gives modularity to the panel 1 according to the invention and avoids the fixing of further components to the layer of sound-absorbing material 4, thus reducing the impairment of its acoustic performance.
It is clear that modifications and variations can be made to the panel 1 described and illustrated herein without thereby departing from the scope of protection defined by the claims.
In particular, the panel 1 according to the invention is also suitable for use in indoor environments characterized by specific operating conditions, such as for example high humidity, wet working environments, etc.

Claims

The sound-absorbing panel (1) comprising a layer of sound-absorbing material (4) and an integrated self-supporting frame (5) supporting the layer of sound-absorbing material (4),
wherein the layer of sound-absorbing material (4) has a front surface (6) apt to be directly exposed to an acoustic source (7) for being struck by sound waves (3) without the interposition of grated elements or other parts, a rear surface (8) opposite the front surface (6), and a lateral surface (10) delimited between the front surface (6) and the rear surface (8);

wherein the self-supporting frame (5) comprises:
- a support profile (11) laterally surrounding at least part of the layer of sound-absorbing material (4) and defining an abutment body for the lateral surface (10) of the layer of sound-absorbing material (4) itself;

- a protective sheet (12) fixed to the support profile (11) and defining an abutment element for said rear surface (8) of the layer of sound-absorbing material (4); and

- at least one containment bracket (13) having a first fixing portion (13a) fixed to the support profile (11) and a second containment portion (13b) cooperating with the layer of sound-absorbing material (4) at said front surface (6);

wherein the sound-absorbing material is made of natural or artificial resin-bonded fibres;

and wherein the layer of sound-absorbing material (4) is releasably interposed and fitted between the second containment portion (13b) and the protective sheet (12).
The sound-absorbing panel as claimed in claim 1, wherein the containment bracket (13) has an L-shaped profile, said first fixing portion (13a) defining a first wing of the L-shaped profile and said second containment portion (13b) defining a second wing of the L-shaped profile configured to cooperate exclusively with a peripheral portion (6a) of the front surface (6) of the layer of sound-absorbing material (4) for pushing the layer of sound-absorbing material (4) against the protective sheet (12).
The sound-absorbing panel as claimed in claim 1 or 2, wherein said support profile (11) laterally surrounds the layer of sound-absorbing material (4) to define a perimetral edge (14) of the sound-absorbing panel (1) itself, against which the lateral surface (10) abuts;
said edge (14) being configured to be releasably fixed to the edge (14) of another sound-absorbing panel (1) to define a modular acoustic barrier (2), wherein each module is defined by one said sound-absorbing panel (1) .
The sound-absorbing panel as claimed in any one of the preceding claims, wherein the sound-absorbing material comprises natural resin-bonded fibres or natural fibres immersed in a resin matrix, said natural fibres being made of cotton fibres.
The sound-absorbing panel as claimed in claim 4, wherein the sound-absorbing material is defined by a lint of resin-bonded cotton comprising 75% cotton and 25% resin, preferably phenolic or epoxy resin.
The sound-absorbing panel as claimed in any one of the preceding claims, wherein the layer of sound-absorbing material (4) comprises a further layer of non-woven polyester fabric that covers the sound-absorbing material, the layer of non-woven fabric defining the front surface apt to be directly exposed to the acoustic source (7).
The sound-absorbing panel as claimed in any one of claims 1 to 3, wherein the sound-absorbing material comprises artificial resin-bonded fibres or artificial fibres immersed in a resin matrix, the artificial fibres being constituted by polyester fibres.
The sound-absorbing panel as claimed in any one of the preceding claims, and further comprising a layer of damping material (16) interposed between the protective sheet (12) and the rear surface (8) of the layer of sound-absorbing material (4),
the layer of damping material (16) being formed by a polymer-plastic-based bituminized element,

the layer of damping material (16) defining a layer of sound-deadening material.
The sound-absorbing panel as claimed in claim 8, wherein the protective sheet (12) is made of ferromagnetic metallic material,
and wherein a magnetic powder configured to interact magnetically with the protective sheet (12) is dispersed in the layer of damping material (16).
The sound-absorbing panel as claimed in any one of the preceding claims, wherein the protective sheet (12) has two ribs (19) obtained on an external surface (18) opposite to an internal surface (17) facing the layer of sound-absorbing material (4),
the two ribs (19) intersecting one another at a central point to define a diamond-point camber of the protective sheet (12) itself at said external surface (18) .