EP4311893A1 - Building panel - Google Patents

Abstract

Building board (1), in particular a wall or ceiling board, with sound absorption properties, which has an upper side and a lower side, a plurality of sound entry recesses (2) being arranged on the sound or visible side, and each sound entry recess having one Width and a wall (5) which is essentially perpendicular to the top and which borders on an edge surrounding the sound entry recess, the majority of at least 85% of the sound entry recesses having a mouth bevel (6) which is in a predetermined angular range one or more angles α at least in a partial section of the edge to the respective wall, the angles α deviating from 90 °.

Description

The invention relates to a building board, in particular a wall or ceiling board, with sound absorption properties, which has an upper side and a lower side, a plurality of sound entry recesses being arranged on the sound or visible side, and each sound entry recess having a width and a wall that is essentially perpendicular to the top and borders on an edge surrounding the sound entry recess.

In the prior art, sound-absorbing panels for indoor or outdoor use are often provided with holes, depressions, wave structures or grooves in order to absorb or redirect sound waves in the audible range of approximately 20 Hz to 20 kHz. Panels of this type are used in meeting rooms, other common areas of buildings, in halls or performance halls as wall or ceiling cladding to improve room acoustics, usually to limit acoustic reverberation effects.

It is particularly known to provide the visible flat surface of a base plate with a large number of vertical bores in order to allow at least a portion of the sound to be lost therein or to superimpose reflected sound components on incoming ones in an extinguishing manner. Although building panels of this type are easy and inexpensive to produce, the quantitative effect of sound absorption is not high, and there is still a need to increase the sound absorption properties.

The US2018090122 discloses a soundproofing panel in which a plurality of penetrating slots are made in a panel, the walls of the slots not always being perpendicular to the plane of the panel. As a result, the absorber power decreases in frequency response by about an octave moved above, but without improving the overall absorber performance.

The WO0203375A1 teaches a sound-insulating body that is covered with a micro-perforated film. The sound-absorbing effect of this item is narrow-band and not particularly high overall.

The EP2540926A1 shows a sound insulation panel in which micro slots with steep walls are attached. The funnel-shaped walls have a very steep, completely circumferential angle and relate to a different vibration model than that discussed here (see below). The disadvantage is that the high angles and the other geometric shapes of the micro-slits can be attached using complex manufacturing processes. The absorber power is also narrow-band and not very high.

The AT515748A1 comprises a sound-insulating building board in which there are a large number of large circular sound entry recesses. In contrast, the invention increases the absorption performance in the low-frequency range.

The invention aims to create a building board as mentioned above, which achieves improved sound absorption properties with simple manufacturing steps. The sound-absorbing effect should be high over wide frequency ranges of the audible spectrum. The solution should be inexpensive and permanent.

The building board according to the invention achieves this in that the majority of at least 85% of the sound entry recesses have a mouth bevel which is in a predetermined angular range with one or more angles α at least in a partial section of the edge to the respective wall, the angle α being 90 ° differ.

A further embodiment of the invention is that the angle α between the mouth bevel of the building board and the wall in the section of the edge is between approximately 70° and 85° or between approximately 95° and 140° degrees. These angle ranges are easy to manufacture and tests have shown that the sound absorption is high.

More specifically, it may be that the angle α between the mouth bevel of the building board and the wall in the section of the edge is between approximately 75° and 85° or between approximately 95° and 120° degrees. These angle ranges are again easier to manufacture and tests have shown that sound absorption is even higher.

It has also proven to be advantageous that more than 85% of the sound entry recesses have a beveled mouth and the remaining minority of the sound entry recesses have an edge to the top of the building board with an angle α of approximately 90 °. This ensures that a clear majority of openings achieve the desired effect and the absorption performance is improved compared to previously known panels.

Furthermore, it is provided that the remaining minority of sound entry recesses have a completely bevelled mouth with an angle α of approximately 85° to approximately 95°. This ensures that the absorption performance is improved compared to previously known panels.

In one embodiment, the width of all sound entry recesses in a building board is approximately 0.1 mm to approximately 2.5 mm. This also increases the sound absorption properties.

A further embodiment of the invention is that the depth of all sound entry recesses in a building board is approximately 0.3 mm to approximately 6 mm, whereby the depth is also the thickness of the building board between the top and bottom. This measure increases both the sound absorption properties and simplifies the manufacturing process.

More specifically, it may be that the width of the mouth bevel is approximately 0.8 to 1.8 times the width of the sound entry recesses. This also increases the sound absorption properties.

It has also proven to be advantageous that the width of the sound entry recesses is also their diameter, which can be easily achieved using the drilling process step.

Furthermore, it is provided that the sound entry recesses are elongated, the length being 2 to 100 times, preferably approximately 15 times, their width (B). This simplifies production and maintains the sound-insulating effect.

In one embodiment, the angle α between the top side of the building board and the wall of a first section of the edge is between approximately 70° and 85° and along a second section of the edge between approximately 95° and 140°. This increases the absorption performance again.

A further embodiment of the invention is to improve the sound-absorbing effect in that the sound entry recesses are arranged in rows on the top, the distances between adjacent sound entry recesses within a row being approximately 0.5 to 2 times the length of the Sound entry recesses or in the case of circular sound entry recesses are approximately 1.5 to 10 times the diameter.

More specifically, it may be that the sound entry recesses are arranged in rows on the top, with the distances between adjacent rows being approximately 0.5 to 2 times the length of the sound entry recesses or, in the case of circular sound entry recesses, approximately 1. 5 to 10 times the diameter.

Alternatively, the sound entry recesses are randomly distributed on the top.

It has also proven to be advantageous that the proportion of the sum of the areas of the sound entry recesses in the total area of the top is approximately 2% to 10%, preferably approximately 5% to 8%. This advantageously achieves a balance between high sound absorption and reduced manufacturing effort.

Furthermore, it is provided that the building board comprises wood, lignified grasses, a light metal such as aluminum or plastic, which advantageously enables a high degree of variability in model series for the building boards.

In one embodiment, the building board consists of wood fiber boards, chipboard, or plywood, which means the appearance can be adapted to existing rooms.

A further embodiment of the invention consists in that it is connected on the back to a support element, a cavity being formed between the underside of the building board and the support element, the cavity preferably having a depth of approximately 3 to 20 times the depth D of the building board . As a result, sound waves are partially swallowed, especially in the audible range.

Furthermore, it is provided that the cavity is formed by the carrier plate designed as a honeycomb plate, perforated plate or coarse-pored foam. This makes the building board even more mechanically stable.

Further advantages and embodiments of the invention result from the description and the drawings. The invention is explained in more detail below using exemplary embodiments shown in the drawings. Show it: Fig. 1 and 2 each showing schematic sections through a section of a building board with a sound entry recess, Fig. 3 and 4 one frequency diagram each, Fig. 5 two sections from a section through a building board and Fig. 6 to 8 each a schematic oblique view through a section of a building board.

• 200 Hz ≈ 0,6 m Wellenlänge λ
  und
• gemäß Fig. 1 einer Breite B der Öffnung im Bereich mit senkrechter Wandung 5
• B < 2,5 mm
• ein Verhältnis
• λ:B > 240
• was als Mikroperforation bezeichnet wird. Bei diesem Effekt wird bewirkt, dass im Gegensatz zu größeren Öffnungen, bei welchen die Schallenergie in eine dahinter liegende Schicht zur dortigen Absorption geleitet wird, hier die Luft an sich (in, vor und hinter der Öffnung in einem allfälligen Hohlraum) zum Schwingen angeregt wird. Da auch Luft eine Masse und somit Trägheit besitzt, stellt sich ein Masse-FederSystem ein, welches letztlich Schallenergie vernichtet, bzw. physikalisch korrekter in thermische Energie umwandelt.

Regarding the acoustics and the physical model of a sound entry recess 2 on a surface 3 according to, for example Fig. 1 or 2 It is known that if the width B of the recess (or diameter in the case of circular openings) is very small in relation to the acoustic wavelength, so-called Helmholtz effects come into play. “Small” means by example

• 200 Hz ≈ 0.6 m wavelength λ
  and
• according to Fig. 1 a width B of the opening in the area with a vertical wall 5
• B < 2.5mm
• a relationship
• λ:B > 240
• what is called microperforation. This effect causes the air itself (in, in front of and behind the opening in any cavity) to vibrate, in contrast to larger openings in which the sound energy is directed into a layer behind it for absorption there . Since air also has mass and therefore inertia, a mass-spring system is created which ultimately destroys sound energy or, more physically correctly, converts it into thermal energy.

A disadvantage of this effect is that the absorption ranges that can be achieved are relatively narrow band. By designing the opening cross sections, said area can be moved, but still remains relatively narrow.

For larger widths B of the sound entry recesses 2 (or openings), a funnel geometry is occasionally used in order to direct more sound, just like with a funnel, into the layers behind it. For small opening sizes, where there is a ratio of λ:B > 240, this makes no sense, as the introduction of sound is not the goal there.

Extensive series of tests have shown that the mouth effect at the small openings changes dramatically when the adjacent surfaces are covered to the opening axis not at 90°, as is usual for micro-perforated surfaces, but at a different angle, for example 75°-110°. This phenomenon results in a significant increase in the absorption area and thus performance. The diagram Fig. 3 illustrates this by forming the area integral under the frequency-dependent absorption curve, which, as can easily be seen, is many times greater than conventional microperforations. Thanks to the logarithmic x-axis, the effect is even greater.

While non-plane surface areas, such as a full-circumference and arbitrarily inclined surface, are known and in use between the individual openings to influence the diffuse reflection, only the immediately adjacent, specifically inclined areas, namely the width S of the mouth bevels 6 is relevant.

The physical explanation is that sound vibrations in air in the form of longitudinal waves, viewed locally, can also be represented as pressure fluctuations. The above-mentioned oscillation of the air in the opening area is caused by and causes a change in the local flow velocity. However, since air is not an "ideal gas", this change does not occur abruptly, but rather 2 areas of different isobars form in a dome shape above the sound entry recesses. The mouth bevels 6 according to the invention in turn result in the formation of overlapping isobaric domes. In interaction with the primary existing ones, interference and extinction effects now arise, which are surprisingly responsible for the extraordinary effectiveness.

There is a clear distinction to macroscopic bevels, funnels, etc. The described effect of the air excited to oscillate can develop primarily in the said small opening dimensions, in which an intentionally small proportion of the sound waves actually flows into the sound entry recesses 2, but the remaining proportion forms the effect just described. Larger openings (sound entry holes with larger widths B and a smaller ratio λ:B < 240 and below) have such bevels the effect of a funnel that directs as many sound waves as possible into an absorber placed behind it. Although the proportions are similar, the fundamentally different scale means that completely different physical mechanisms work.

In connection with the area of micro-perforation present here, it is also sufficient if not all, but only a sufficiently large proportion of the sound entry recesses 2 are beveled, and if the mouth bevels 6 also only affect a part of the circumferential edge of a sound entry recess 2 . This circumstance can be used to take into account any statistically occurring differences in the geometry of the sound entry recesses 2 depending on the building board material and the manufacturing process, but ultimately to be able to allow them with regard to the efficiency to be achieved here (see embodiments of Fig. 6 to 8 ).

• B = 0,5 mm; D= 3 mm; L= 5 mm (Länge der Schlitze),
• α = 105° ... 45% Anteil,
• α = 80° ... 40 % Anteil,
• α = 90° ... 15 % Anteil,
• Anteil an offener Fläche 6,6% bezüglich der Gesamtfläche der Bauplatte 1.

The diagram in Fig. 3 shows its exemplary product geometry in a test stand, called the “Alpha cabin”. As an example, an absorption coefficient a (without units or [1]) of an optimal structure (dotted line) is shown to illustrate the absorption degree in comparison to the prior art (solid and dashed lines). For the exemplary structure of a building board according to the invention, the parameters are selected as follows:

• B = 0.5mm; D=3mm; L= 5 mm (length of the slots),
• α = 105° ... 45% proportion,
• α = 80° ... 40% proportion,
• α = 90° ... 15% proportion,
• Proportion of open area 6.6% of the total area of building board 1.

The area integral under the absorber curves, expressed in aHz, is the fictitious absorber power for visualizing the performance of the individual variants, rounded to increments of 100. For the building board according to the invention it is in diagram of Fig. 3
1700aHz.

• US2018090122 "prior Art" = 800 aHz,
• US2018090122 "present" = 900 aHz.

The solid line corresponds to the performance of the US2018090122 "prior species"; the dashed line corresponds to the performance of the US2018090122 "present".

• US2018090122 "prior type" = 800 aHz,
• US2018090122 "present" = 900 aHz.

• B = 0,5 mm; D= 3 mm; L= 5 mm,
• α = 90° etwa 100 % Anteil,
• Anteil an offener Fläche 6,6%.

This already shows the advantage of the invention. In Fig. 4 , which also shows absorption curves of three plates in comparison, the performance is compared with a conventional micro-perforated plate in which the edges of the sound entry recesses are 90° (solid line). The parameters are:

• B = 0.5mm; D=3mm; L = 5 mm,
• α = 90° approximately 100% proportion,
• Share of open space 6.6%.

This would result in an output of approximately 850 aHz and the additional disadvantage of narrowband (absorption peak at around 1000 Hz).

• α = 105° ... 25% Anteil,
• α = 100° ... 25% Anteil,
• α = 85° ... 25% Anteil,
• α = 80° ... 25 % Anteil.

The absorption curve of a building board according to the invention with the same parameters as in Fig. 3 is in Fig. 4 applied again in dotted form. An alternative building board according to the invention with a different distribution of the mouth bevels 6 is shown in a dashed line. The distribution is (with otherwise identical parameters to the dotted line):

• α = 105° ... 25% proportion,
• α = 100° ... 25% proportion,
• α = 85° ... 25% proportion,
• α = 80° ... 25% share.

The performance is very similar in terms of frequency response and area integral.

The sound entry recesses 2 can be produced by milling, punching, water jets, laser cutting, compressed air granulate cutting or the like. This can be selected depending on the material of the building board 1 and/or its surface. The material of a building board 1 is essentially not relevant for the special effect of the sound entry recesses. Vibration technology Materials with a bulk density in the range of 300 to 2700 kg/m ³ have proven themselves. The materials in question are therefore plastics, wood materials, solid wood and light metals. Wood materials also include lignified grasses, such as bamboo and the like. A first process step therefore consists of providing a raw material for a building board 1 with regard to the external dimensions and any coatings and, in a second step, initially producing the sound entry recesses 2 without mouth bevels 6. For this purpose, the shape, number and distribution of the sound entry recesses 2 are taken from a model and realized by drilling, milling, embossing, water jets, laser cutting or punching. Alternatively, at least some sound entry recesses 2 already have sufficient mouth bevels 6 on parts of their edges in the sense of the invention, ie those with the above-mentioned angular ranges.

The mouth bevels 6 can be realized by milling or similar machining or machining, by blasting compressed air granules, embossing or compacting, or, in the case of solid wood, by brushing. The brushing result can be achieved, for example, through a special sequence of one to four process steps using different brush materials. Starting with steel strands, followed by brass, Andalon and nylon bristles.

The arrangement of the sound entry recesses 2 in the surface of a building board 1 works over wide areas. However, an arrangement in rows that are evenly spaced from one another and in which the recesses are at the same distance from one another is easier to produce in series and is often preferred for installation for optical reasons. For the highest sound-absorbing effect, the sound entry recesses 2 must be evenly distributed over the surface. For a high effect, the proportion of open area through the recesses is approximately 1-10%, preferably 3-8% and more preferably 6.6% of the total area.

The rows can be aligned synchronously or offset from one another. Both alternatives work equally well in terms of sound absorption properties.

The opening geometry for a sound entry recess 2 can be designed differently. Tests have shown that the width B of a sound entry recess 2, always measured in the area with a vertical wall 5, is 0.1-2.5 mm, preferably 0.5-1.5 mm. The depth D of a sound entry recess 2 is then 0.3-6 mm, preferably 0.8-4.5 mm and particularly preferably 1.5-3.5 mm. The mouth bevel S is ideally 0.8 to 1.8 times the width B. The angle α from wall 5 to the mouth bevel, which should deviate from 90°, preferably from the range 85°-90°, in both Directions, according to the test results, is 70°-140° (excl. 90°) and preferably 75°-120° (excl. 85°-95°).

The manufacturing process will preferably produce the sound entry recesses 2 not individually by pressing, embossing, brushing, machining or punching, but in large numbers at the same time, with the exact opening geometry only statistically corresponding to the specified data. Alternatively, in serial manufacturing processes, such as jet cutting, the sound entry recesses are not produced simultaneously, but individually, one after the other in rapid succession. This statistical distribution can also occur here. However, this does not reduce the sound absorption function (and the aesthetic design) of the building board 1. The proportion of sound entry recesses 2 whose angle α falls in the range of 85°-95° that should be avoided should, however, be less than 15% of all sound entry recesses 2 of a building board 1.

According to Fig. 5 The mouth bevels 6 can be concave or convex. This may be caused by a manufacturing process such as brushing wood materials. Such shapes also do not limit the sound-absorbing effect of the sound entry recesses 2. In order to be able to determine and achieve the desired angular range of the angle α, one sets oneself on the central tangent 7 of the curved mouth bevel 6 in order to obtain a straight line and intersect with the line of the wall 5.

As in Fig. 7 clarified, the angle α of the mouth bevel 6 of a sound entry recess 2 in a section smaller than 90 ° can change into a section larger than 90 °. The particularly high sound-absorbing effect remains received in the process; Incidentally, despite an intermediate, short section of the mouth bevel 6, in which the angle α is close to or at 90 °.

The sound entry recess 2 can have a round cross section or as an elongated slot as in Fig. 6 to 8 shown can be provided. The maximum length of such a slot is limited to 20 mm, preferably 15 mm, so that the building board 1 is not mechanically unstable, ie at risk of breakage. The shape of the slot ends is not primarily relevant for the acoustic effect and can therefore be left dependent on the manufacturing process, depending on whether it is easier to provide the slot ends with a mouth bevel 6, or to leave a 90 ° edge, or else Make the slot ends rectangular in plan view or end with a radius.

The distances between the sound entry recesses 2 result in the values for within a row, between the rows or the average distances with an arbitrary, disordered distribution of all sound entry recesses 2 from the open area (sum of the area of the sound entry recesses 2) and the desired proportion in % of the area of the building board 1.

If the sound entry recesses 2 are provided as slots, they can be straight or curved or have other geometries. From the perspective of simple production, straight-line sound entry recesses 2 are suitable, but also curved or similar for reasons of consistency or the desired contrast with the room surroundings of the installed panels. With regard to the acoustic effect, no differences could be measured depending on these alternatives.

The mouth bevel 6 does not need to be linear/straight across its width S, but can be disordered as in Fig. 8 be indicated. As described above, such shapes can be created by brushing uneven wood materials, but are not detrimental to the sound-absorbing effect and can be tolerated. As a result, the angle α and width S of the mouth bevel 6 at a sound entry recess 2 vary. It is important that the angle α lies within the ranges described here as effective.

The building board 1 is advantageously part of a higher-level structure in that it rests on a basic structure. It must be ensured that there is a more or less self-contained air space behind the building board 1 described above with the sound entry recesses 2. This means that you either build a box-shaped construction (not shown), in which the building board 1 is firmly connected to a base plate and there is a predefined cavity between the two. Its depth (seen in the same spatial direction as the depth D of the building board 1) is then matched to the depth D of the building board 1. The cavity serves the small portion of sound waves that enter the sound entry recesses 2. Even with the optional provision of a cavity behind the building board 1, the formation of the mass-spring system and Helmholtz effect is also supported.

Or you can choose the mechanically more stable alternative because it is more rigid, in which the building board 1 is held by a honeycomb-shaped structure or by (hardened) e.g. coarse-pored foam material. The building board 1 lies directly on the second, cavity-containing structure.

By varying the volume behind the building board 1, i.e. on the underside 4 facing away, the frequency response can be fine-tuned acoustically, but this would be the subject of another invention.

Reference symbol list

1

Building plate

2

Sound entry recess

3

Top

4

bottom

5

wall

6

Mouth bevel

7

Middle tangent

b

Width of a sound entry recess

D

Depth of a sound entry recess

S

Width of a muzzle bevel

α

angle

Claims (15)

Building board, in particular wall or ceiling board, with sound absorption properties, which has an upper side and a lower side, a plurality of sound entry recesses being arranged on the sound or visible side, and each sound entry recess having a width and a substantially wall standing perpendicular to the top, which borders on an edge surrounding the sound entry recess, characterized in that the majority of at least 85% of the sound entry recesses (2) have a mouth bevel (6) which is in a predetermined angular range with one or more Angles α is at least in a partial section of the edge to the respective wall (5), the angles α deviating from 90 °. Building board, according to claim 1, characterized in that the angle or angles α between mouth bevels (6) of the majority of sound entry recesses (2) and the walls (5) in the section of the edges between approximately 70 ° and 85 ° and / or between is approximately 95° and 140° degrees. Building board, according to claim 1, characterized in that the angle or angles α between the mouth bevels (6) of the majority of the sound entry recesses (2) and the walls (5) in the partial section of the edges are between approximately 75° and 85° or between approximately 95 ° and 120° degrees. Building board according to one of claims 1 to 3, characterized in that more than 85% of the sound entry recesses (2) have a mouth bevel (6) and the remaining minority of the sound entry recesses (2) completely have an edge towards the top (3). Building board (1) with an angle α of approximately 90 °, and preferably the remaining minority of the sound entry recesses (2) have a mouth bevel (6) with an angle α of approximately 85 ° to approximately 95 °. Building board according to one of claims 1 to 4, characterized in that the width (B) of all sound entry recesses (2) of a building board (1) is approximately 0.1 mm to approximately 2.5 mm, the width (B) in particular is the diameter of the sound entry recess (2). Building board according to one of claims 1 to 5, characterized in that the depth (D) of all sound entry recesses (2) of a building board (1) is approximately 0.3 mm to approximately 6 mm, the depth (D) also being the thickness the building board (1) between the top (3) and bottom (4). Building board according to one of claims 1 to 6, characterized in that a width (S) of the mouth bevel (6) is approximately 0.8 to 1.8 times the width (B) of the sound entry recesses (2). Building board according to one of claims 1 to 7, characterized in that the sound entry recesses (2) are elongated, the length being 2 to 100 times, preferably approximately 15 times, their width (B). Building board according to one of claims 1 to 8, characterized in that the angle α between the mouth bevel (6) and wall (5) of a first section of the edge is between approximately 70° and 85° and along a second section of the edge is between approximately 95° and is 140°. Building board according to one of claims 1 to 9, characterized in that the sound entry recesses (2) are arranged in rows on the top side (3), the distances between adjacent sound entry recesses (2) within a row being approximately 0.5 up to 2 times the length of the sound entry recesses (2) or, in the case of circular sound entry recesses (2), approximately 1.5 to 10 times the diameter. Building board according to one of claims 1 to 10, characterized in that the sound entry recesses (2) are arranged in rows on the top side (3), the distances between adjacent rows being approximately 0.5 to 2 times the length the sound entry recesses (2) or in the case of circular sound entry recesses (2) are approximately 1.5 to 10 times the diameter. Building board according to one of claims 1 to 9, characterized in that the sound entry recesses (2) are randomly distributed on the top side (3). Building board according to one of claims 1 to 12, characterized in that the proportion of the sum of the areas of the sound entry recesses (2) in the total area of the top (3) is approximately 2% to 10%, preferably approximately 5% to 8%. Building board according to one of claims 1 to 13, characterized in that it comprises wood, in particular wood fiber boards, chipboard, or laminated wood, or lignified grasses, a light metal such as aluminum, or plastic. Building board according to one of claims 1 to 14, characterized in that it is connected on the back to a support element, a cavity being formed between the underside (4) of the building board (1) and the support element, the cavity preferably having a depth of approximately 3- up to 20 times the thickness D of the building board (1), and the cavity is formed in particular by the carrier plate designed as a honeycomb board, perforated board or coarse-pored foam, which rests directly on the underside (4) of the building board (1).

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