EP2575127A1 - Acoustic absorption element - Google Patents

Abstract

The element has plate (2) that is provided with a first plate surface (4) which is intended to face a noise source. The first plate surface is arranged opposing the second plate surface (6). The plate is provided with sound absorption columns (12) which are continuous in thickness direction and not continuous in the transverse direction (Q). The sound absorption columns are arranged successively in the longitudinal direction (L) to limit the width of each of two spaced-apart slit side surfaces (14,16). An independent claim is included for manufacturing method of sound absorption element.

Description

The present invention relates to a sound absorption element according to the preamble of claim 1 and to a method for producing the sound absorption element.

Sound that is generated in a room spreads out as an airborne sound wave and hits room boundary surfaces that partially absorb and partly reflect the sound. Depending on the desired room acoustics, it may be necessary to provide additional elements for absorption or for reflection or scattering of the sound.

Generic sound absorption elements have been known to the skilled person for a long time. Depending on their mode of operation, they are assigned either to the porous absorbers or the resonance absorbers. While in the porous absorbers, the sound energy is converted into heat by friction of the air molecules in the absorber, it is converted into kinetic energy of the mass in resonance absorbers, which comprise a vibrating mass and a spring. As mass, plywood, plasterboard or pressboard can be used in so-called plate swingers. In perforated plates (so-called perforated plate vibrators) the air oscillating in the hole acts as a mass. The spring is formed by the trapped behind the plate volume of air.

A device for producing a perforated plate is approximately in EP-A-0686963 described. This includes a rotating drum and a plurality of them mounted flexible polymer plates with needles embedded therein, which are intended to apply a predetermined gap pattern on an acoustic panel.

The CH-B-698 170 again refers to a sound absorbing element in the form of a dimpled sheet with holes, wherein the holes are formed as slit-like openings with smooth edges and smooth ends.

A particular directed to the improvement of the room acoustics sound absorption element is in the CH-B-697 277 disclosed. This has a front side and a multiplicity of rotationally symmetrical recesses extending from the front side into the element, which have a section in which they taper in cross-section as viewed from the outside to the front side.

However, those are in the CH-B-697 277 described sound absorbing elements in their production relatively complex. In addition, the resonance frequencies are determined by the rear edge of the recesses or their limitation, wherein different shapes of the boundary effect different resonance frequencies. Thus, an element designed for a specific space is according to CH-B-697 277 limited in its use to this space and can not be easily adapted to the acoustic characteristics of another room in terms of sound absorption properties.

Object of the present invention is therefore to provide a sound absorption element with very good absorption properties, which can be easily manufactured and flexibly adapted to the respective room acoustics.

The object is achieved by a sound absorption element according to claim 1. Preferred embodiments are given in the dependent claims.

Thus, the invention relates to a sound absorbing element comprising a plate having a first plate surface intended to face a sound source and a second plate surface opposite and spaced from the first plate surface by the thickness of the plate and two opposite plate side surfaces.

The plate has transversely extending sound absorption gaps which are continuous in the thickness direction and non-continuous in the transverse direction and whose width is bounded in each case by two gap side surfaces spaced from each other. The sound absorption gaps are thus open, as a result of which the sound impinging on the sound absorption element, according to the principle of the perforated plate vibrator, sets the air in the respective gap into oscillation.

At least two sound absorption gaps are arranged consecutively in the (perpendicular to the transverse direction) longitudinal direction.

According to the invention, a first part of the sound absorption gaps starts from a first of the two side surfaces of the plate and passes therethrough in the thickness direction through the plate; a second part of the sound absorption column starts from the second of the two plate side surfaces and at this in the thickness direction through the plate. In each case two longitudinally successive sound absorption gaps in the transverse direction are offset from one another and arranged overlapping each other.

Due to the specific arrangement of the sound absorption column, the plate is flexible. This implies that the plate can be both stretched and compressed elastically by applying force parallel to its plane. In addition, there is flexibility transverse to the plane of the plate. In particular, the plate can be elastically bent or rotated (by the action of a torsional moment).

The plate is flexible even when a material comprising wood and / or plastic is used, which is naturally rigid.

The invention thus makes it possible to align the topography of the sound absorption element according to the respective space requirements in an almost unlimited manner. In particular, the sound absorption gaps or the material webs formed between the sound absorption gaps can be aligned with the sound source in such a way that optimum sound absorption (through the gaps) or sound reflection and sound scattering (through the material) is obtained. At the same time, the flexibility of the plate allows almost any adjustment of the volume of air on the side facing away from the sound source side of the plate, whereby a very wide frequency spectrum can be absorbed.

In addition, such a high degree of flexibility can be achieved with the arrangement according to the invention of the sound absorption gaps that the plate is characterized by low-frequency Sound is vibrated and thus in this frequency range by the material of the plate itself a sound absorption is achieved.

Overall, the invention thus allows both in terms of sound absorption as well as in terms of sound reflection and sound scattering optimal adaptation to the particular room acoustics, which are also limited in terms of adaptation to the geometry of space limits.

The sound absorption element of the present invention thus necessarily has open sound absorption gaps. It differs fundamentally from previously known sound absorption elements in that the material is flexible due to the arrangement of the sound absorption gaps.

In general, the width of the sound absorption gap, i. the distance from the one gap side surface to the other side surface gap of a gap, greater than about 1.5 mm, preferably greater than about 3 mm.

In addition to the gap width, the gap length and the respective gap from gap to gap are decisive for the flexibility of the plate and the absorption properties of the sound absorption element. These too can be optimally adapted depending on the objective. In general, the gap length is in a range of 40 mm to 200 mm, preferably in a range of 50 mm to 80 mm. The distance between two longitudinally successive gaps is usually in a range of 2 mm to 15 mm, preferably in a range of 2 mm to 10 mm and particularly preferably in a range of 3 mm to 5 mm.

Since the sound absorbing element is particularly designed for use in rooms of a building, the plate is preferably formed of a material comprising wood and / or plastic, as is commonly used for wall coverings. As mentioned, the plate is flexible by the inventive arrangement of the sound absorption column in the choice of this material.

In the sense of a uniform as possible flexibility of the plate go according to a preferred embodiment, emanating from the plate side surfaces sound absorption column in the longitudinal direction alternately from opposite side surfaces of the plate.

It is further preferred that every second of the longitudinally superimposed sound absorption gaps is configured identically in terms of its extension and its arrangement in the transverse direction, which is likewise in the sense of uniform flexibility and, moreover, of a highly aesthetic appearance.

It is further preferred that the sound absorption gaps have a rectangular shape in a section through a sectional plane running parallel to the plate surfaces. Such a plate is easily accessible from a production point of view, as described below in connection with the method according to the invention, and moreover exhibits very good absorption properties.

In this regard, it is further preferred that in the unbent state of the plate, the column side surfaces extend in mutually substantially parallel planes. This is in the Contradiction with the relevant prior art documents, in particular the doctrine of CH-B-697 277 according to which it is precisely essential that the side wall of the recess has an inclination varying over the depth of the recess.

It is also conceivable, however, for the sound absorption gaps to have a different axisymmetric shape than a rectangular shape in a section through a sectional plane running parallel to the plate surfaces. In particular, conceivable is a lens mold.

According to a particularly preferred embodiment, at least one of the sound absorption gaps is designed in such a way that its extension in the transverse direction (i.e., its length) in the thickness direction decreases at least in sections continuously. This results in a Schallaufnehmer- or sound collection effect, which further enhances the absorption properties of the inventive sound absorption element.

It has surprisingly been found that sufficient flexibility of the plate is also obtained in this embodiment, provided that the longitudinally successive sound absorption gaps on one of the plate surfaces in the transverse direction overlap with each other, while on the other plate surface two longitudinally consecutive longitudinal sound absorption gaps also with each other overlap or their ends are flush with each other (ie have a distance of about 0 mm in the transverse direction) ..

While providing the advantages of this preferred embodiment, it is intended to provide a disk, which has an identical gap pattern on both plate surfaces, then the plate can be formed from two identical partial plates, each with different gap patterns on their partial plate surfaces, wherein the partial plates are connected such that the respective partial plate surfaces lie on each other with the same slit pattern. The resulting plate thus has the same gap pattern on both sides; Although it is formed of two partial plates, it is nonetheless flexible.

As a rule, those partial plate surfaces are connected to each other, on which the sound absorption gaps have a shorter length than on the opposing partial plate surface.

In this context, it is further conceivable to provide a textile layer between the plates. This can be used for about the adjustment of the flexibility or the strength of the plate. It is also conceivable, however, to provide a sound-absorbing textile, such as an acoustic fleece, in order to additionally increase the absorption properties.

The connection of the two plates can be made by any conceivable method which appears suitable to the person skilled in the art and generally takes place by means of a bond.

According to a further preferred embodiment, at least two of the sound absorption gaps lie on a straight line in the transverse direction. Consequently, there are several separate sound absorption gaps on a transverse straight line, which are separated from one another by material webs. This allows the Flexibility of the plate can be adjusted in almost any way without their stability would be unacceptably impaired. According to a particularly preferred embodiment, at least one of the two side walls of the plate does not extend from the sound absorption gaps lying on a straight line. As a result, a very high strength is ensured without this would severely affect the achievable flexibility.

Depending on the objective, it may be further preferred for a sound absorption gap or two or more sound absorption gaps lying on a straight line in a region near the surface to form a groove extending from one plate side surface to the other plate side surface. It is conceivable that the groove is formed only on one or both plate surfaces.

Typically, the longitudinally successive sound absorption gaps are each equidistant, which results in uniform flexibility over the entire length of the component.

It is also conceivable for the plate to have two further plate surfaces running at right angles to the described plate surfaces and plate side surfaces, in which sound absorbing gaps in turn are arranged as described above. In this case, the longitudinal direction corresponds to the first two opposite plate surfaces of the thickness direction with respect to the second two opposing plate surfaces and vice versa.

According to a further aspect, the present invention relates to a method for producing the above-described sound absorption element, wherein the plate is obtained from a plate-shaped structure in which the absorption gaps are formed by removing material.

According to a particularly simple and therefore preferred embodiment of the invention, the removal of material by means of a circular saw, preferably a multi-blade circular saw unit.

It is conceivable that the milling takes place only from one side, i. that the circular saw is lowered only in one of the two plate surfaces. This results in the rule for the circular saw facing plate surface a greater gap length (corresponding to a closer to the circle center chord) than for the circular saw facing away from the plate surface (corresponding to a further distant from the circle center chord), which corresponds to the preferred embodiment described above.

Preferably, the circular saw is moved in the transverse direction parallel to the plate surface, wherein it is lowered at the points provided for this purpose in the thickness direction in the plate. More preferably, the circular saw oscillates in the thickness direction while being transversely driven, describing a sinusoidal curve.

Fig. 1

eine perspektivische Ansicht einer Platte einer ersten Ausführungsform des erfindungsgemässen Schallabsorptionselements in gebogenem Zustand;

Fig. 2

eine perspektivische Ansicht einer Platte einer weiteren Ausführungsform des erfindungsgemässen Schallabsorptionselements in gebogenem Zustand;

Fig. 3

eine perspektivische Ansicht einer Platte einer weiteren Ausführungsform des erfindungsgemässen Schallabsorptionselements in gebogenem Zustand in Explosionsdarstellung, wobei die Platte zwei Teilplatten und eine dazwischen angeordnete Textileinlage umfasst;

Fig. 4

einen Ausschnitt einer Plattenoberfläche gemäss einer weiteren Ausführungsform der Erfindung in der Draufsicht;

Fig. 5

einen Schnitt eines Teils der in Fig. 1 gezeigten Ausführungsform durch eine quer zur Plattenebene verlaufende Schnittebene;

Fig. 6

einen Schnitt eines Teils der in Fig. 2 gezeigten Ausführungsform durch eine quer zur Plattenebene verlaufende Schnittebene; und

Fig. 7

eine graphische Darstellung der für einzelne Frequenzen gemessenen Nachhallzeit in einem Raum mit eingebauten Schallabsorptionselementen gemäss der vorliegenden Erfindung im Vergleich zur Nachhallzeit in einem Raum ohne erfindungsgemässe Schallabsorptionselemente.

The invention will be illustrated in detail with reference to the figures. From these shows:

Fig. 1

a perspective view of a plate of a first embodiment of the inventive sound absorbing element in a bent state;

Fig. 2

a perspective view of a plate of another embodiment of the inventive sound absorption element in the bent state;

Fig. 3

a perspective view of a plate of another embodiment of the inventive sound absorbing element in the bent state in an exploded view, wherein the plate comprises two partial plates and a textile insert disposed therebetween;

Fig. 4

a section of a plate surface according to another embodiment of the invention in plan view;

Fig. 5

a section of a part of in Fig. 1 shown embodiment by a plane transverse to the plane plane cutting plane;

Fig. 6

a section of a part of in Fig. 2 shown embodiment by a plane transverse to the plane plane cutting plane; and

Fig. 7

a graphical representation of the measured reverberation time for individual frequencies in a room with built-in sound absorption elements according to the present invention in comparison to the reverberation time in a room without inventive sound absorption elements.

As in Fig. 1 combined with Fig. 4 is shown, the plate 2 of the inventive sound absorbing member comprises a first plate surface 4 and a first plate surface opposite, in a plane parallel thereto and spaced by the thickness of the plate second plate surface 6. The plate defines a longitudinal direction L and a transverse direction Q, such as in Fig. 4 is shown.

Incidentally, the plate has two opposite plate side surfaces 8, 10, which extend in a plane perpendicular to the plate surfaces 4, 6.

How farther Fig. 1 and 4 it can be seen, the plate 2 has transversely extending Schallabsorptionssspalte 12. These are continuous in the thickness direction D (see, for example, FIG Fig. 5 ) and in the transverse direction Q are not continuous and are each bounded by two spaced gap side surfaces 14, 16.

In the longitudinal direction L, a plurality of sound absorption gaps 12 are arranged in succession. In this case, a first part 12a of the sound absorption column 12 extends from a first of the two plate side surfaces 8 and at this in the thickness direction through the plate. A second part 12b of the sound absorbing gaps 12 extends from the second of the two plate side surfaces 10 and therethrough in the thickness direction through the plate. In each case two successive in the longitudinal direction L Schallabsorptionssspalte 12 are offset in the transverse direction Q to each other and arranged overlapping each other.

As in the Fig. 4 As shown in the embodiment shown, every second one of the longitudinal absorption L superimposed sound absorption column 12 is designed to be identical in terms of its extension and its arrangement in the transverse direction Q. In this case, the sound absorption gaps 12 have a rectangular shape, with their expansion in the transverse direction Q continuously decreasing in the thickness direction D, so that the expansion of the respective sound absorption gap 12 in the transverse direction Q on the first plate surface 4 is greater than on the second plate surface 6.

In the in Fig. 1 In the embodiment shown, the sound absorption gaps 12 are milled into the plate such that they form (only) on one of the two plate surfaces 4 in a near-surface region 15 a groove 17 extending from one plate side surface 8 to the other plate side surface 10. Such a plate is obtained approximately when the milling for generating the sound absorption gaps takes place only from one side, in the figure from the side of the first plate surface 4 ago. It is conceivable, for example, that the milling is done with a circular saw, which - while it is driven in the direction of a plate side surface 8 and 10 to the other plate side surface 10 and 8 - permanently sawed into the material of the plate.

A corresponding sectional view is in Fig. 5 shown. According to this material webs 18 are obtained, which have approximately the shape of an isosceles and symmetrical trapezium in section, the two diagonals are slightly curved concave. In the area of the plate side surfaces corresponding material webs 18 'are obtained, which is a form of a right triangular triangle with a curved concave hypotenuse on average. The bending is due to the fact that, during sawing, the inclination of the gap in the thickness direction D continuously decreases from the first plate surface 4 to the second plate surface 6, and continuously increases from the second plate surface 6 to the first plate surface 4.

In the Fig. 2 The embodiment shown differs from that in FIG Fig. 1 On the other hand, the sound absorption gaps 12 on both plate surfaces 4, 6 form a continuous groove 17 in a respective near-surface region 15. Such a plate is obtained approximately when the milling for generating the sound absorption column of done on both sides; a corresponding sectional view with an approximately sectioned in the shape of a hexagon or an isosceles triangle material web 18 "or 18"'is analogous to Fig. 5 in Fig. 6 shown.

Alternatively, it is conceivable, two plates according Fig. 1 as part plates 2a, 2b to connect with each other, wherein the part plate surfaces 6a, 6b, on which the sound absorption column 12 do not form a continuous groove, are interconnected. The plate thus obtained has one of the plate of Fig. 2 corresponding external appearance, ie that on both plate surfaces 4a, 4b the sound absorption gaps form a continuous groove. It is also conceivable that between the partial plates 2a, 2b, a textile insert 20 - such as an acoustic fleece - is inserted, as in Fig. 3 will be shown.

The sound absorption obtained with the sound absorption element according to the invention is achieved by means of the in Fig. 7 shown results of the reverberation time shown. The measurement was based on the standard SN EN ISO 3382 "Acoustics - Measurements of room acoustics parameters - Part 2: Reverberation time in ordinary rooms (ISO 3382-2: 2008)", using the precision method.

Specifically, the measurement was carried out in a usual use according to the furnished room, with windows and doors were closed.

The reverberation times measured for the respective octave bands are given in Table 1, the values obtained for a room equipped with the sound absorption elements according to the invention being compared with the values for a room without said elements (reference). The measurement uncertainties in the sense of a standard deviation in% of the measured value are given in Table 2. Table 1 octavo 125 Hz 250 Hz 500 Hz 1 KHz 2 KHz 4 KHz with sound absorption element 1.90 1.95 1.95 1.77 1.62 1.29 reference 0.91 0.98 0.95 0.96 0.91 0.77 octavo 125 Hz 250 Hz 500 Hz 1 KHz 2 KHz 4 KHz with sound absorption element 2 1 1 1 1 1 reference 3 2 2 1 1 1

In the Fig. 7 The graph of these results shown clearly shows the reduction of the reverberation time due to the sound absorption obtained according to the invention. This was also reflected in a greatly improved speech intelligibility, which - measured according to the standard EN 60268-16 - was consistently good for rooms with the sound absorption element according to the invention.

Claims (15)

A sound absorption element comprising a plate (2) having a first plate surface (4) intended to face a sound source and a second plate surface (6) opposite and spaced from the thickness of the plate and two opposite plate side surfaces (Fig. 8, 10),
the plate having transversely extending sound absorption gaps (12) which are continuous in the thickness direction (D) and non-continuous in the transverse direction (Q) and whose width is bounded by two spaced gap side surfaces (14, 16) and at least two sound absorption gaps ( 12) are arranged successively in the longitudinal direction (L),
characterized in that a first part of the sound absorption gaps (12a) starts from a first one of the two plate side surfaces (8) and passes therethrough in the thickness direction (D) through the plate (2), a second part of the sound absorption gaps (12b) from the second one both plate side surfaces (10) goes out and passes therethrough in the thickness direction (D) through the plate and each two in the longitudinal direction (L) successive Schallabsorptionsspalte (12) in the transverse direction (Q) offset from one another and are overlapping each other. Sound absorption element according to claim 1, characterized in that the plate (2) is made of a material comprising wood and / or plastic. Sound absorption element according to claim 1 or 2, characterized in that the plate (2) is flexible. Sound absorption element according to one of the preceding claims, characterized in that the sound absorption gaps extending from the plate side surfaces (8, 10) extend in the longitudinal direction (L) alternately from opposite plate side surfaces. Sound absorption element according to one of the preceding claims, characterized in that each second of the longitudinal direction of (L) arranged on each other Schallabsorptionssspalte (12) with respect to its extension and its arrangement in the transverse direction (Q) is configured identical. Sound absorption element according to one of the preceding claims, characterized in that the sound absorption gaps (12) in a section through a plane parallel to the plate surfaces (4, 6) extending cutting plane have a rectangular shape. Sound absorption element according to one of the preceding claims, characterized in that in the unbent state of the plate (2) the column side surfaces (14, 16) extend in mutually substantially parallel planes. Sound absorption element according to one of the preceding claims, characterized in that at least one of the sound absorption gaps (12) is designed such that its extension in the transverse direction (Q) in the thickness direction (D) decreases at least in sections continuously. Sound absorption element according to one of the preceding claims, characterized in that in the transverse direction (Q) at least two of the sound absorption gaps (12) lie on a straight line. Sound absorption element according to claim 9, characterized in that of the lying on a straight line Schallabsorptionssspalte (12) at least one of the two plate side walls (8, 10) emanates. Sound absorption element according to one of the preceding claims, characterized in that a sound absorption gap (12) or at least two lying on a straight line Schallabsorptionssspalte (12) in a near-surface region (15) from one plate side surface (8) to the other plate side surface (10) through Form groove (17). Sound absorption element according to one of the preceding claims, characterized in that it further comprises a support having a base and a frame surrounding the base, from which the plate is held. A sound absorbing member according to claim 12, wherein the plate is held in a non-planar shape by the frame. Method for producing a sound absorption element according to one of the preceding claims, characterized in that the plate is obtained starting from a plate-shaped structure in which the absorption gaps are formed by removing material. A method according to claim 14, characterized in that the removal of material by means of a circular saw, preferably a multi-blade circular saw unit.

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