DE20006946U1 - Broadband sound absorbing component for walls, floors and ceilings - Google Patents

Description

Breitbandiq sound-absorbing component for walls, floors and Cover

The invention relates to a broadband sound-absorbing component for walls, floors and ceilings of the type mentioned in the preamble of claim 1.

It is already known that in concert halls, in order to improve the so-called "room acoustics", large sound-reflecting surfaces, especially walls and ceilings, can be clad with "curtain" panels that have perforations. Through friction with an absorber lying or standing behind them and/or with the perforated walls, sound energy is converted into heat energy and thus absorbed. This is intended to make the acoustic impression when attending a concert as similar as possible to that of an open space.

In addition, it is known (DE 43 15 759 Cl and Bauphysik 1994, pages 69 to 80) to arrange components designed as glass panes at a certain distance from sound-reflecting walls. By using transparent glass or plastic, the covered walls are to appear almost completely optically, but the incident electromagnetic waves of the visible wavelength range

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area as fully as possible. The sound waves hitting the transparent glass panes should partially pass through their openings in order to convert sound energy into heat energy through friction on the walls of the openings, which does not cause any disturbance. It is also known to use glass panes with a convex configuration instead of flat ones. Using this principle, it is also known to provide thin transparent films with micro-perforations if the space does not allow the attachment of glass or artificial glass components. According to this principle, it is also known (EP 0 697 051 Bl) to install so-called "suspended ceilings" at a distance from the ceiling of the building room in question. These are made of metal, plastic or wooden panels and have a hole diameter of less than 2 mm and a hole area ratio (LV) (that is, the ratio of the area occupied by the openings to the total area) of less than 3%. It is important that the distance between the suspended ceiling and the ceiling, i.e. the distance required for the air gap, is precisely maintained in order to tune the resonance maximum of the absorption, which is typical for microporous absorbers designed in this way, to the desired frequency. Distances between about 2 0 and 150 mm are considered necessary for the audible sound wave range.

The invention is based on the object of perfecting sound-absorbing components in such a way that they are easier to manufacture and less dependent on maintaining this distance between the clad wall or ceiling on the one hand and the perforated or holed component on the other, and offer a broader absorption spectrum.

MÜILEK. SCIIUPFNER 1 GAUGER

The invention consists in the joint application of the following partial features:

(a) The mean diameter or width of the holes (which form the holes or perforations in the plate and/or layer) is between 0.001 and 2 mm, in particular between 0.001 and 0.1 or 0.095 mm.

b) The layer or plate thickness is between 0.01 and mm, in particular between 0.051 and 1.9 mm.

c) The hole area ratio (LV) is between 0.1 and 20%, in particular between 3 and 10%.

Surprisingly, it has been shown that with such a "miniaturization" of the perforations, a quite astonishing absorption effect can be achieved despite a likewise minimal hole area ratio. In contrast to the state of the art according to the previous information, microporous panels dimensioned in this way result in a much broader sound absorption curve.

A preferred field of application of the invention is also the lateral limitation of roadways on which loud noises occur, in order to act as so-called "noise barriers" to largely dampen the propagation of sound to areas next to the roads or the like.

In addition, the invention can also be used to cover walls, floors and ceilings. Preferred uses are road surfaces, coverings for noise barriers, which can be used when transparent materials such as glass or

MÜLLER. SCIIUPFNER 1 UAUUER

Plastic, which can also be made transparent, facade components of buildings and cladding of walls, ceilings and/or floors of acoustic measurement rooms, which should remain as free of sound reflection as possible, or of rooms which, due to aggressive media, moisture, heat or hygienic requirements, should only be lined with corrosion-free, resistant and easy-to-clean materials such as stainless steel or aluminum.

The arrangement of such cladding is essentially parallel to the object to be clad, i.e. floor, ceiling and/or measuring room wall. However, the perforated panels and layers can also be arranged at right angles to the clad building parts or to the roadway. In the case of a noise barrier, the panels or layers run essentially vertically, while in the case of cladding measuring room walls, an essentially horizontal arrangement of the panels or layers can also be expected to produce good results.

Also possible are stretched micro-perforated plastic films, but also hanging blinds, curtains, etc., with which the "acoustics" of a room can be varied.

The layers or plates can also serve as a carrier for an additional porous covering layer, in particular made of foamed plastic or nonwoven fabric.

For many applications, it is recommended to use a perforated layer or plate that is three-dimensionally deformed, which can be achieved in particular by deep drawing a flat plastic component or by injection molding or transfer molding into the desired shape.

MÜLLER. SCIIUPFNER \ UAUUER

Although the miniature openings can be created during the plate production, it is recommended that they be perforated later, particularly by "drilling" with a laser beam. Other high-energy beams, including electrical discharges using arcs or particle bombardment, can also be used to create the miniature holes. Mechanical perforation with needle and/or knife rollers also offers a suitable and industrially viable production option.

Particularly preferred are openings that are not circular but in the form of fine slits. The slot width should be between 0.02 and 0.18 mm, while the slot length can be between 0.02 and 30 mm. In this case, non-cutting deformation or warping is recommended, particularly by stretching, similar to the way expanded metal is produced. First, the openings are made in the form of fine slits and/or holes in the layer or plate. During or after this, the layer is stretched and/or three-dimensionally deformed by rolling without cutting. In many cases, it is also advisable to partially close the openings again during rolling in order to maintain the small miniature dimensions.

Exemplary embodiments of the invention are shown schematically below with reference to the drawing. Figure 1 shows a schematic plan view of a part of the component in a significantly enlarged representation and

Figure 2 is a schematic partial view of a component designed as expanded metal according to the invention;

MÜLLER. SCIIUPFNtK & 1'.AUGER

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Figure 3 shows a greatly enlarged partial section of a component according to the invention in the region of an opening;

Figure 4 is a plan view of the area of the part of Figure 3 around the aperture of circular cross-section;

Figures 5 to 10 Examples of the arrangement of the component according to the invention

The component according to Figure 1 consists of a plate 1 made of aluminum with a layer thickness of L = 0.4 mm. The plate 1 is provided with a multitude of slot-like openings 2, which have a slot length 1 of in particular 1.6 mm and a width b (at the widest point) of 0.09 to 0.1 mm. The distance a1 between adjacent openings 2 is approximately 1 mm (calculated from the corresponding sides of the slots) and the distance a2 between corresponding ends of adjacent slots is approximately 2.5 mm, so that an effective distance c is obtained according to the formula

c = a2 - 1

of 0.9 mm.

Figure 2 shows another embodiment of the invention, which corresponds more closely to the expanded metals previously used for other purposes. The plate 1 with a layer thickness L of 0.5 mm is first slit with a knife bar and stretched in such a way that the narrow slits become approximately

MÜLLER. SCIIUPFNEK &Lgr; IW

• · in · · S

diamond-shaped openings 2, whereby at the same time the originally flat surface of the plate 1 is warped without chipping. The slot width b in the finished component according to Figure 2 is approximately 0.1 mm with a web width c of approximately 0.03 mm. The illustration is not to scale.

In the embodiment of Figure 1, the number of slots is 1000/m over the length of the component and the number of slots is 400/m over the width or height of the built-in part, i.e. parallel to the longitudinal extension LE of the slot-shaped openings

According to Figure 3, the plate made of polypropylene has a hole 2 with a substantially circular cross-section at a certain point. The hole 2 has a diameter D of, for example, 0.5 mm. The length L of the hole 2, which corresponds to the thickness of the plate 1, is 3 mm in this example, so that a hole area LF is obtained according to the formula

LF = π · D ²

of 0.2 0 mm ² and a volume V of

V = LF · L of 0.6 mm ³

The acoustic waves W _A hitting the perforated plate 1 are mostly reflected as reflection waves W _R on the surface of the perforated plate 1, while another part, namely the passing waves W _D , penetrates into the hole 2 and initiates physical effects in the gas volume located there, which lead to a much

MÜLLER. SCIIUPFNER Sl UAUUER

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greater absorption of the total incident waves than corresponds to the hole area ratio LV. The hole area ratio LV is the ratio between the hole area LF occupied by holes 2 in relation to the total area GF occupied by both holes 2 and the surface of the perforated plate 1 according to the following formula

LV = LF/GF

according to the relationships shown schematically in Fig. 4.

According to Fig. 5, the component is connected to other layers to form a multi-layer absorber element. Several individual layers 1 can lead to a significant increase in broadband compared to a single layer by correctly selecting the perforation. This can further improve absorption, particularly in the low frequency range. Spacers 11 keep the individual layers 1 at a distance from one another, forming air layers or gaps 12.

Figure 6 shows a schematic cross-section of the installation of a multilayer absorber element consisting of four individual layers in front of a wall. Spacers 11 are also used here.

According to Figure 7, a corresponding multi-layer absorber is attached to both sides of a noise barrier 10. The spacers can also be designed as so-called "cassettes", i.e. box-like structures delimited by walls on four sides and open on both ends.

MÜLLER, SCIIUPFNER It UAUUER

According to Figure 8, the individual panels 1 are arranged in front of the wall 10, at right angles to it, immediately adjacent to it at a distance from one another and at right angles to the wall 10. The component arrangement can be designed in the manner of a "shelf system" but also in the manner of a "honeycomb system" with a particularly rectangular honeycomb structure.

Figure 9 shows an elevation of a measuring chamber delimited by walls 10. The walls 10 are shown on the inside with a multi-layer structure of flat component plates 1 according to the invention, which are separated from one another by spacers.

Figure 10 shows a cross-section of a floor or road surface which is in turn constructed from several layers 1 of the perforation according to the invention which are arranged one above the other at a distance from one another and in particular have different perforations.

MILLER. SCIIUPFNER Ik GAUIiER

Claims (14)

1. Broadband sound-absorbing component for walls, floors and ceilings with at least one perforated plate and/or layer ( 1 ) with a thickness of less than 50 mm, in which the openings ( 2 ) have an average diameter (D) and/or an average width (b) of less than 2 mm and a hole area ratio (LV) (ratio of the area occupied by the openings to the total area) of not more than 20%, characterized by the combination of the following features: a) The mean diameter (D) or the mean width b) the apertures ( 2 ) are between 0.001 and 2 mm, in particular between 0.02 mm and 0.1 mm, c) the layer or plate thickness (L) is between 0.01 and 50 mm, in particular between 0.051 and 1.9 mm with the exception of 0.1 mm, and d) the hole area ratio (LV) is between 0.1% and 20%, in particular between 3 and 10%. 2. Component according to claim 1, designed as a noise barrier part next to roadways, such as roads or railways. 3. Component according to claim 1, designed as a floor covering, in particular a road surface. 4. Component according to claim 1, designed as a facade element of buildings. 5. Component according to claim 1, designed as a structural element for the delimitation of acoustic measuring rooms. 6. Component according to one of the preceding claims, characterized by the arrangement substantially parallel to the floor, the ceiling and/or the measuring room wall. 7. Component according to one of claims 1 to 5, characterized by the arrangement substantially vertically and substantially at right angles to the roadway. 8. Component according to one of claims 1 to 5, characterized by the essentially horizontal arrangement essentially at right angles to the measuring chamber wall. 9. Component according to one of the preceding claims, characterized in that the openings ( 2 ) are designed as fine slots in the layer or plate ( 1 ) with a slot width (b) between 0.02 and 0.18 mm and a slot length ( 1 ) between 0.02 and 30 mm and the area around the openings ( 2 ) is deformed or discarded without cutting, in particular stretched. 10. Component according to one of the preceding claims, characterized in that the perforated layer or plate ( 1 ) serves as a carrier for a porous covering layer formed in particular from foamed plastic or nonwoven fabric. 11. Component according to one of the preceding claims, characterized in that the perforated layer or plate ( 1 ) is three-dimensionally shaped or deformed. 12. Component according to claim 11, characterized in that the perforated layer or plate ( 1 ) is designed as a deep-drawn or injection-molded plastic part. 13. Component according to claim 12, characterized in that the plastic part is transparent or translucent. 14. Component according to one of the preceding claims, characterized in that the perforated layer or plate ( 1 ) is formed from pressed, glued and/or fused fibers.