CH702952A2 - Sound absorbing noise barriers. - Google Patents

Abstract

There are sound-absorbing plate-shaped elements (1) and a method for their preparation proposed, which allow extremely efficient stable sandwich construction of acoustically effective cover layers (10, 20) and an inner supporting core (30) of corrugated web profiles (31, 32) build. The corrugated web profiles (31, 32) define air channels in the plate interior and are designed and / or arranged such that the two sound-absorbing surfaces (10, 20) communicate with each other in a communicative manner. The elements (1), for example, for use in noise protection along roads and railways, made of transparent or translucent material. The core (30) consists of only one or a few components and stabilizes the sound-absorbing plate-shaped element (1) sufficiently. Since preferably all portions of the corrugated web profiles (31, 32) in the core (30) are oriented substantially in the vertical direction and the plate interior is free of horizontal walls or shoulders, the contamination is avoided and facilitates the cleaning.

Description

The present invention relates to sound-absorbing plate-shaped elements according to the preamble of the independent patent claim 1 and noise barriers according to the preamble of claim 9, comprising corresponding sound-absorbing plate-shaped elements, and method for the production of acoustic elements according to the preamble of claim 12.

Despite increased efforts of vehicle manufacturers and road builders has increased continuously for years as a result of strong growth in road and rail traffic and traffic noise. To make matters worse, that with higher cruising speeds and the noise level increases. With the increasingly dense population of our habitats, the increasing traffic leads to increased noise pollution of more and more people. The increasing mobility in the professional and leisure sectors combined with the increasing urban sprawl inevitably leads to an even greater increase in traffic noise. The noise pollution meets less the road users in the car or on the train, because these thanks to sound-absorbing and sound-absorbing components and materials in the means of transport are only exposed to a small extent even the noise. The traffic noise primarily pollutes the residents.

Noise is not only subjectively perceived as disturbing, but is also responsible for many health problems. In Switzerland alone, it is estimated that the cost of noise from road and rail transport is more than CHF 1 billion. According to calculations by the Swiss Federal Office for Spatial Development (ARE), these noise-related health costs already amounted to CHF 2,000,124 million for the year 2000 and the noise-related loss of rent accounted for CHF 874 million. In view of these costs and the increasing awareness of the topic for the public, costly and kilometer-long noise barriers along the traffic routes are required outdoors.

However, the known soundproofing walls often act only as sound insulation, the noise is shielded by the wall but not reduced. Finally, the noise is reflected on the opposite side, or deviates unhampered upwards on double-sided noise barriers. In densely populated habitats, such measures often no longer suffice, because this diffuse environmental noise exceeds the bearable and permissible level. In order to prevent this, soundproofing walls with sound absorbers are increasingly being used, which not only shield the sound, but absorb it.

In known Schallschluckern or absorbers made of metal, wood or plastics with fleece and insulation inserts each part of the sound energy is converted into heat. However, these absorbers lose their effect very quickly due to the large amount of dirt along the traffic routes or are severely restricted in this area. Cleaning the dirty absorber or sound absorber is practically impossible. Soundproof corridors with sound absorbers, which until now have been designed without exception as opaque walls, also considerably impair the quality of life of direct residents. Light and visibility are denied by intransparente walls not only the residents, but also the traveler. The bottom line is that the well-known Schallschlucker the quality of life is not really increased, since for a reduction of noise, the loss of light and vision must be taken into account.

There is an urgent need for transparent or at least translucent noise barriers with transparent absorbers. However, such products are not available in the market despite the clear demand so far.

Two main reasons for this situation are: a. The inexpensive and easy to apply fiber materials are not transparent and therefore not applicable. b. The microperforated transparent absorbers, which have been used indoors for a number of years, or for room acoustics, do not meet the high outdoor requirements (for example, rain, wind and, above all, soiling).

The pollution problem is known already in the non-transparent metal, wood and plastic absorbers in the outdoor area. The applicant has been producing micro-perforated transparent absorbers for room acoustics for years. The manufacturing method used here comprises the following steps: punching into single-layer and double-layer absorbers with 0.75 mm thick PET cover layers which are glued to sandwich elements with a honeycomb core, similar to that shown in FIG. 1 from the prior art. It caused by such horizontal honeycomb elements in the plate interior closed chamber systems which show no negative impact in the interior area. In the outdoor area, rain, moisture and dirt can penetrate into the honeycombs through the perforated cover layers. While the water can evaporate over time, the dirt accumulates in the honeycomb. The entrained dirt (abrasion of tires and brake pads as well as dust) will over time and in combination with any growth by microorganisms such as fungi and algae to cloud the elements lead to complete opacity. Since a cleaning of the bonded sandwich panels is not possible or only with disproportionately high effort, the elements would have to be replaced at regular intervals. Above all, this pollution problem makes it impossible to use these known products outdoors.

It is therefore an object of the present invention to provide sound-absorbing elements for noise barriers and methods for producing the same, which have good sound-absorbing properties meet all the requirements for stability and resistance for use in outdoor areas and are low maintenance and cost , It is a further object of the invention that the sound-absorbing plate-shaped elements on request translucent (translucent) or transparent (translucent) and can be produced quickly and economically with reasonable technical effort. In addition, further disadvantages of the known sound-absorbing elements should be avoided.

It is a further object of the present invention to provide noise barriers that are at least partially transparent or translucent, and not only reflect incident sound, but absorb it.

These objects are achieved according to the invention by the acoustic elements according to claim 1, the manufacturing method according to claim 9 and noise barriers according to claim 12, advantageous embodiments will become apparent from the dependent claims.

The novel sound-absorbing plate-shaped elements comprise a first and a second sound-absorbing cover layer and an inner supporting core. They are characterized in that the core comprises corrugated web profiles which define air channels in the plate interior and are designed and / or arranged such that the two sound-absorbing surfaces communicate with each other in a communicative manner.

Preferably, the first and the second sound-absorbing cover layer are provided with a micro-perforation comprising holes with a diameter of 2.0 mm or less, preferably between 0.3 to 1.1 mm, particularly preferably 0.55 mm. The term holes is to be understood below, unless otherwise stated, acoustically active slots or slots with widths of 0.5 to 2.0 mm or openings with the same functional cross section but other cross-sectional shapes. The absorbers according to the invention act as so-called microperforated absorbers (MPA for short) which are known to the person skilled in the art and whose mode of action is described, for example, in WO 9424 382A and WO 9 426 995A1 by the Fraunhofer Society and numerous other patents and scientific publications by the inventor Prof. Dr. med. Helmut Fuchs is described. In the MPAs, the air in the interspace swings to a reverberant wall as a spring in the manner of a Helmholz resonator. The sound waves rub in holes or slots with a small cross-section and are converted into heat energy. The sound is attenuated.

In the sound-absorbing plate-shaped elements according to the invention, the air in the air ducts also acts advantageously as a spring in the manner of a Helmholtz resonator.

In preferred embodiments, the core comprises at least two corrugated web profiles, which are offset transversely to a channel longitudinal axis or phase-shifted from each other. Alternatively or additionally, the corrugated web profiles may be provided with openings through which the two sound-absorbing surfaces are in communicating connection with one another. According to further preferred embodiments, the sound-absorbing plate-shaped elements are made segmented, wherein a single segment comprises only one corrugated web profile, but at least two segments are combined to form an element, that in this turn the corrugated web profiles are offset transversely to a channel longitudinal axis or out of phase with each other.

It has been shown that a wide variety of profile shapes are suitable for the Wellstegprofile. Preferred profile shapes are selected from the group sinusoids, trapezoidal profiles, triangular profiles or tube profiles. The corrugated web profiles in the plate core play an essential role in the mechanical stability of the plates. For production-related and therefore economic reasons, the microperforations in the cover layers or cover plates are to be punched. Needled facings are unstable due to their small thickness and are useful only as a foil. The punched hole image, that is, the grid in which the holes are arranged, must be selected for acoustic reasons with a hole spacing of less than 2.0 mm, preferably in the range of 0.5 to 2.0 mm. Although thicker outer layers of 2.0 mm and more could make the problematic honeycomb cores superfluous due to their greater intrinsic stability, they can no longer be punched with reasonable effort. It is known to the person skilled in the art that this value of 2.0 mm is material-dependent, and that with soft material thicker, but with thinner material only thinner cover plates can be punched. The well-known shrinkage of the holes after punching (by about 0.1 to 0.3 mm) can be used here to improve the absorption. In addition, the holes, or the hole diameter, after punching can still be reduced by post-processing steps, such as by rolling, whereby an improvement in the acoustic effect can be achieved.

For reasons of stability, the cover layers should preferably not be selected to be thinner than 0.6 mm.

The known extruded double-wall sheets are not suitable for subsequent punching, since the punch must forcibly interact with the punching die and must not impinge on air or on a web.

The profiles are according to the present invention in the finished built-in sound-absorbing elements for outdoor use preferably oriented so that penetrating water and thus also any leaked by the micro perforation dirt with gravity can flow down. This type of arrangement or alignment of the corrugated webs in the plates allows the gravity driven drainage of water and dirt.

For indoor applications, the vertical arrangement of the corrugated web profiles in the elements is less critical. The advantageous acoustic effect is largely independent of the orientation of the web profiles. However, in interior applications, the aesthetic aspects often play a more important role, so that the alignment of the bar profiles, which is visible in both the transparent and the translucent elements, is specifically used by the interior designer or client in order to achieve an additional visual design goal. The webs are preferably arranged vertically or horizontally in the elements, as this can be implemented most efficiently in production. If necessary, however, the webs can be arranged in any deviating angle. In order for the air in the space between the two perforated cover layers to act as a spring in the manner of a Helmholtz resonator, there must also be connections between at least individual air channels on both sides. The core must - as already mentioned above - be continuous for sound waves. A closed profile between the two perforated cover layers would prevent effective absorption.

According to a first embodiment of the present invention, the web profiles are provided in the sound-absorbing plate-shaped elements with openings or openings to both perforated cover layers out, which allow the communicating connection. When dimensioning the bar profiles and / or when choosing the material, it must be taken into account that the openings or openings in the bar profiles weaken their mechanical stability. According to a further embodiment of the present invention, the connections required for the acoustic effect between the two perforated cover layers are produced inside the sound-absorbing plate-shaped elements in that the core comprises at least two corrugated web profiles which offset transversely to the channel longitudinal axes (hereinafter also laterally offset) or phase-shifted) are arranged to each other. The present invention thus makes it extremely efficient to build a stable sandwich construction from two acoustically effective cover layers and an inner supporting core, wherein the core consists of only one or a few components, the sound-absorbing plate-shaped element sufficiently stabilized and still communicate the necessary for the acoustic effect of the Ensures connection between two cover layers and also all shares are aligned substantially in the vertical direction to prevent contamination and facilitate cleaning.

According to a further embodiment of the inventive method corrugated web profiles are produced with laterally offset portions in a continuous manufacturing process for the production of the core. This can be done, for example, by the fact that the desired lateral offset is generated during the extrusion of a corresponding profile in regular sections, and thereby the necessary breakthroughs occur in the profile material in the transition from one section to the next.

The corrugated sheeting according to the invention can also be produced in discontinuous processes, for example by deep drawing in a mold or by pressing between two molds.

In the production of the segmented elements described above, it has proven to be advantageous to produce a corrugated web profile plate without transverse offset, preferably in an endless process to cut this semi-finished product to the desired segment length and to assemble elements of the invention in the desired size. The individual segments can be glued or welded together, or kept in a frame construction.

Decisive for the use in the outdoor area is that water and dirt in all embodiments alone driven by gravity can drain without cascades. In order to support this inherent cleaning effect, the elements in the installed state according to certain embodiments of the invention can also be designed to be open at the top. The inner longitudinal channels are additionally rinsed by rain in open-top embodiments. The elements are preferably open at the bottom or at least provided with drainage holes to prevent accumulation of water, which could for example lead to frost damage in winter.

In the elements according to the embodiments of the present invention with vertical alignment of the corrugated web profiles not only front and back can be easily cleaned, but the interior can be completely cleaned from the top without much effort. In embodiments with horizontal profiles this is no longer possible, in embodiments in which the deviation of the profile longitudinal axes is less than 90 ° from the vertical, all channels are still accessible from above or at least from the side and can be cleaned. Since the water should flow gravity-driven, a certain slope in the channels is advantageous.

All internal surfaces can be easily rinsed, for example with a steam or high pressure cleaner. It has proved to be particularly advantageous that hinder the cleaning solutions or the rain and the dissolved or suspended therein dirt during drainage between the outer layers no horizontal crossbars or honeycomb. The concentration of dirt in the inventive elements can be effectively prevented.

The web profile, for example, a sine profile, may be constructed of two or more profile sections, which are arranged laterally offset from one another between the cover layers or cover plates. In a preferred embodiment, the respectively adjacent profile sections are offset by a half period or arranged in phase relation to one another. Accordingly, when there are more than two profile sections in the plate-shaped element, the first and the third professional sections do not differ in terms of phase, but are arranged congruently one above another in the view from the top. For segmented elements, this transverse offset is preferably achieved very easily by tilting individual segments (for example, the 2nd, 4th, 6th, etc.) around 1800.

The number of sections or segments and the degree of lateral offset can be selected depending on the profile shape and the size of the sound-absorbing elements to be produced. The flow resistance increases with the height of the sections, that is with the distance of the offset areas and vice versa, for optimal sound absorption is a flow resistance of 400 to! 200 Ns / m <3>. Absorption and flow resistance are determined in cooperation with the hole diameter of the microperforation and the open perforation surface. The desired absorption is only achieved if the structure of the supporting core ensures the communicating connection of the two sound-absorbing surfaces via air channels in the plate interior. As already mentioned above, the air in the air channels of the inventive sound-absorbing elements acts advantageously as a spring in the manner of a Helmholtz resonator. Due to the additional targeted selection of size, number and shape of the openings in the Wellstegprofilen, the height of the individual Profi labschnitte, the surface finish of the profiles and formed by the offset of the individual profile sections open, communicating connection between the air channels can also be the flow resistance and thus affecting the sound absorption.

Without departing from the teaching of the invention, it can also be transferred to multilayer absorber elements. In this case, more than one core layer is arranged between two outer cover layers. The corrugated web profiles of the individual core layers can be directly connected to each other, or be separated by intermediate layers or plates.

It is crucial that these intermediate layers or plates in turn do not interrupt the communicating connection between the acoustically active outer layers. This can be ensured for example by a perforation or other suitable breakthroughs.

The new technical teaching according to the present invention can be applied not only in outdoor areas, but also in room acoustics and represents an alternative to the known honeycomb cores. The longitudinally offset profile systems make it possible with transparent and translucent absorbers over the known absorbers to achieve new and improved optical properties with honeycomb core structures. The previous honeycomb cores considerably limit the transparency and the viewing angle. This is far less the case with the new vertically arranged and offset corrugated web profiles without any loss of stability.

The method for producing the new sound-absorbing plate-shaped elements comprising at least a first and a second sound-absorbing cover layer and an inner supporting core is characterized in that micro-perforated for producing the two sound-absorbing cover layers, a plate-shaped semifinished product in a punching process between the punch and the punching die and two cover layers produced in this way are then adhesively bonded to at least one corrugated web profile as the core to form a sandwich element, so that air channels are defined inside the board and designed and / or arranged such that the sound-absorbing cover layers communicate with each other in a communicative manner.

For the production of the core, according to a preferred embodiment of the method according to the invention, sections of corrugated web profiles are produced and glued laterally offset from one another between the cover layers. When selecting the corrugated web profiles used, care is taken to ensure that the contact surfaces between the profiles and the cover layers are not too large in order to avoid that too many of the microperforations in the cover layers are covered and sealed after bonding.

According to further embodiments of the inventive manufacturing method, a corrugated web profile is produced with laterally offset portions in a continuous manufacturing process for the production of the core.

The inventive sound-absorbing plate-shaped elements are ideal for creating micro-perforated absorber walls, preferably made of transparent or translucent plastic, for noise barriers for rail and road transport. The microperforated absorber walls are preferably preceded by a solid glass or synthetic glass rear wall for sound insulation. In a common frame construction, the transparent sound-absorbing elements can be arranged parallel to and spaced from the reverberant glass or synthetic glass walls, with the absorbing elements being executed to the noise source. The sound-absorbing elements are used in conjunction with glass walls preferably as a modular system and are easily replaceable in case of damage.

In order to protect the sound-absorbing elements in outdoor use from damage by hail, stone chipping and other mechanical effects, the elements are preferably preceded by a perforated protective screen or a protective grid. The perforation of this protective screen is not a microperforation, but the openings are of a size that hailstones or stones can not penetrate, but the sound can sufficiently reach the absorbing elements and is not easily reflected. The openings can take various forms, from circular over slit-shaped, rectangular, triangular, quadrangular or polygonal to irregularly polygonal or rounded.

The protection of the sound-absorbing elements can also be achieved by a lamellar wall, in which individual protective fins spaced from each other or partially overlapping, are arranged like a tile.

All protective screens are again preferably made of transparent or translucent materials.

An additional beneficial effect of using upstream shields is that the invaded sound that is not absorbed is reflected back to the inner wall of the shield and reflected in part by this again and in a second passage of the acoustically effective surface of the sound-absorbing element can be absorbed.

The distance between the protective screen and the sound-absorbing element or elements can be optimized to the structural conditions. The distance between the sound-absorbing elements and the rear walls, however, is preferably optimized to the desired frequency range, since this space serves as a resonator.

Since in the sound-absorbing plate-shaped elements according to preferred embodiments, the corrugated web plates and thus the air ducts defined by them in the installed state in the vertical direction, the deposition of water and or dirt in the interior of the elements is reduced to a minimum. Inside, the elements are free of horizontally running wall surfaces or heels on which dirt could be deposited. The inventive elements can - as already described - in the installed state top and bottom open, or preferably closed at the top with a lid that can be easily removed for cleaning purposes. Alternatively, nozzles can be arranged in the lid or in the upper region of the elements, via which the interior of the elements can be rinsed from the outside without having to remove a lid.

In order to be able to withstand the mechanical loads in the outdoor area, the absorber elements according to the invention must be able to withstand wind and, in addition, pressure and suction forces from passing road and, above all, rail vehicles.

If necessary, the transparent or translucent elements, respectively the absorber walls constructed therefrom, can be designed as back-lightable light walls and can replace additional lighting devices such as street lamps.

For outdoor use, high demands are placed on the materials used. From the prior art, for example, façade panels made of plastic, which must be able to cope with similar requirements. Preferred plastics include polyolefins, in particular polypropylene (PP), polyethylene (PE) and / or cycloolefinic copolymers (COC), polyalkylene (meth) acrylates, in particular polymethylmethacrylate (PMMA), poly (meth) acrylimides (PMMI), polycarbonates ( PC), polyisocyanates, polyoxyalkylenes, in particular polyoxymethylene (POM), polyesters, in particular polyethylene terephthalate (PET), polybutylene terephthalate (PBT) and / or polyethylene-2,6-naphthalate (PEN); Polyether ketones, in particular polyether ether ketone (PEEK), polyether sulfones (PES), polysulfones (PSU), polyphenylene sulfides, polyvinyl chlorides, polystyrenes (PS), polyamides (PA), polyurethanes and / or polyimides (PI). The use of copolymers which have two or more repeating units of which the aforementioned polymers are made, such as styrene-acrylonitrile (SAN), acrylic ester-styrene-acrylonitrile (ASA) and acrylonitrile-butadiene- Styrene polymers (ABS) is known. The polymers can be used individually or as a mixture of two, three or more plastics (blends).

It is also known that the plastics may contain additives such as UV stabilizers, impact modifiers, dyes, pigments, antistatic agents, flame retardants and fillers. These additives allow the adaptation of the plate properties to specific requirements, for example to the desired temperature-resistant in the range between -40 ° C to 50 ° C. The surfaces of all elements associated with the surrounding atmosphere may be biocidally or biostatically endowed to counteract the growth of algae, fungi, bacteria, lichens, mosses and / or the like. For this purpose, for example, in a known manner silver compounds in the plate materials and / or applied to the respective surfaces. Other suitable biocides or biostats are known to those skilled in the art. The equipment of surfaces with self-cleaning and / or water-spreading properties or the application of paints for mechanical improvement (scratch resistance, impact resistance, etc.) is also possible.

When painting or equipping the surfaces with the acoustically active microperforations, however, care must be taken that the additional paint or finishing layers do not impair the acoustic effect of the microperforation. Preferably, therefore, the microperforation is produced only after such a coating or equipment. It is important to avoid that the coating causes the sound to be reflected and the friction necessary for absorption to be avoided in the microholes of the microperforation.

To produce the noise barriers according to the invention, the sound-absorbing plate-shaped elements are preferably used as insertion elements for insertion into stable frame elements. Such a frame element preferably comprises a transparent or translucent front protective screen, as has already been described above, and a soundproof closed rear wall. Two side walls are provided with corresponding insertion grooves or recesses for positive reception of the insertion elements. The insertion element replaces the hitherto conventional opaque nonwovens and insulation mats as absorbers and allows for the first time the production of transparent and / or translucent noise barriers for outdoor use. The frame members are preferably guided and held in a known manner in vertically mounted U-profiles made of metal.

Brief description of the figures

On the basis of figures, which represent only embodiments, the invention will be explained below. Show it <Tb> FIG. Fig. 1 is a view of a partially opened acoustic element having a horizontal honeycomb core known in the prior art; <Tb> FIG. 2 <sep> is a view from above of a sound-absorbing element according to a first embodiment; <Tb> FIG. 3 <sep> is a view from above of a sound-absorbing element according to a further embodiment; <Tb> FIG. Fig. 4 is a perspective view of a partially cut element according to the first embodiment of Fig. 2; and <Tb> FIG. 5 <sep> is a perspective view of a partially cut element according to the first embodiment of FIG. 3. <Tb> FIG. FIG. 6 shows a perspective view of a sound-absorbing element according to another embodiment for use in the interior with a horizontally extending profile, and FIG <Tb> FIG. 7 shows a perspective view of a partially opened and cut wall element of a noise protection wall, with sound-absorbing elements with vertically extending profiles according to a further embodiment of the invention.

FIG. 2 shows a schematic top view of a sound-absorbing plate-shaped element 1 according to a first embodiment of the present invention. Between a first inner cover layer 10 and a second outer cover layer 20, two rail sections 31, 32 are arranged and form a core 30. The two corrugated web section sections 31, 32, in cooperation with the inner and outer cover layers, form a multiplicity of air channels 33, 34 Illustration in which the element 1 is viewed from above as seen from above, it is well seen that the adjacent air channels 33, 34, which are formed by the profile section 31, over the entire surface with underlying, formed by the profile section 32, air channels in communication. In the example shown with the sinusoidal profile sections 31, 32, which are offset by exactly half a wavelength laterally to each other, each of the upper air ducts 33, 34 in conjunction with three underlying air ducts. Since the profile sections 31, 32 are aligned exactly vertically, the interior of the element 1 does not have any horizontal walls or protrusions which could hinder the drainage of water or could allow the settling of dirt. It is clear at first glance that an element 1 with the inventive inner construction can be cleaned well from above. A cleaning device, for example a nozzle of a high-pressure or steam cleaner, can be easily introduced into the air ducts 33, 34 formed between cover layers 10, 20 and corrugated web profiles 31, 32. This even over several profile sections.

In the example shown, both cover layers 10, 20 are provided with a microperforation of 300,000 holes per square meter. The thickness of the element 1 is 20 mm.

The element has a sufficient intrinsic stability to be used with edge lengths of up to 1250 x 2500 mm.

When used in a noise protection wall, not shown, such an element could be mounted at a distance of 30 mm in front of a 10-20 mm thick glass or plastic glass in a common frame construction.

In the perspective view of Fig. 4, in which a right upper corner region of the sound-absorbing plate-shaped element 1 is cut off, the staggered arrangement of the two profile sections 31, 32 is clearly visible. The individual corrugated web profile sections 31, 32 in the exemplary embodiments illustrated do not have any openings or openings. The corrugated web profile sections touch at their respective vertices over the entire height alternately the outer cover layer 20 and the inner cover layer 10 and form with these in FIG. 4 dashed lines indicated contact lines K. The cohesive connection of web plate 31 and cover layers 10, 20 along these lines of contact the adjacent vertically extending air channels 34, 35, 36 from each other, so that in the region of the individual corrugated web section 31 is not communicating the connection between the inner 10 and outer cover layer 20. Only the staggered arrangement of the corrugated web section sections 31, 32 ensures that air channels which are assigned in the upper section of the inner cover layer 10 are in the lower section with air channels in communicating the connection, which are associated with the outer cover layer. In this way, without breakthroughs in the surface of the corrugated web profiles, it is ensured that there is a communication between the inner and outer cover layers 10, 20 over the sections. The staggered arrangement of the corrugated web profile sections 31, 32 makes the plate-shaped elements very stable and connection-rigid.

It is clear from the synopsis of FIGS. 3 and 5 that the principle according to the invention can also be implemented with other shaped corrugated web profiles 41, 42. In the example shown, regular, trapezoidal corrugated web profile sections 41, 42 are arranged between an inner cover layer 20 and an outer covering layer 20 and form a sound-absorbing plate-shaped element 2. The corrugated web profile section 41 lying above in the illustrated plan view is in contact with the inner sides of the inner 10 via contact surfaces 43 and 44 and the outer cover layer 20 in conjunction.

With elements as shown in FIGS. 2 to 5, in comparative tests air permeabilities of 30 to 120 liters / m 2 / second and the above-mentioned desired flow resistances of 400 to! 200 Ns / m <3>.

When used indoors, so for example in open-plan offices, meeting rooms, schools, etc., provide the transparent sound-absorbing elements according to the present invention, the architects and acoustics in terms of design options advantages over the known transparent elements. The profile structure in the core allows sound-absorbing elements to be used, which visually have a clear line and offer the viewer a much quieter image than, for example, known honeycomb elements. Such an element 3 with horizontally extending profile is shown in FIG. The element 3 comprises a front and a back microperforated cover layer 11, 21 and a core 61 of a trapezoidal corrugated web profile with a plurality of wall openings 62, 63. The openings 62, 63 are formed as elongated slots, which also extend in the horizontal direction and the Support the optical effect of the profiles. The openings 62, 63 establish a communicating connection between the air channels in the plate interior. They each connect a front air duct 64 between sound-absorbing front surface 11 and core profile 61 with a rear air duct 65 between sound-absorbing rear surface 21 and core profile 61 with each other.

It is shown in FIG. 7 that transparent microperforated elements, as described for example with reference to FIG. 6 in an application for the interior area, can also be used in wall elements in the form of composite segmented sound-absorbing elements. The wall element 50 shown by way of example comprises a base 57, a closed reverberant rear wall 51, a front protective screen 52 with a plurality of openings and two side walls 53, 54 with vertical grooves 55, 56 for receiving and positionally supporting the sound-absorbing elements 4, 5. The protective screen 52 is only partially shown and gives the view of the two elements 4, 5, which are vertically stacked in the grooves 55, 56 and form a functional absorber unit in the form of a segmented, composite plate-shaped absorber element. The two individual elements 4, 5 thus act as segments, but are as described above for Fig. 6 provided with openings 58 in the walls of the Wellstegprofile. In contrast to the element 3 from FIG. 6, the elements in the exemplary embodiment according to FIG. 7 are tilted by 90 °, so that the profiles run vertically. The openings represent in the example shown, a first communicating connection between the acoustically active front and rear cover layers. A second communicating connection is achieved in the composite element by means of transverse displacement of the air channels of the individual segments 4, 5. The wall element 50 is shown in FIG. 7 cut horizontally. Depending on requirements and desired height, it can accommodate three, four or more individual absorber elements 4, 5 arranged one above the other and closed at the top with a cover (not shown). The individual absorber elements each comprise two cover layers of 0.75 mm thick plastic glass, which are microperforated (0.5 mm hole diameter, hole spacing / grid 1.8 × 1.8 mm) and glued to a trapezoidal profile. The illustrated elements 4, 5 are 1250 mm wide and 300 mm high. The height can be advantageously chosen between 300 and 4000 mm. In the example shown, the individual elements are offset from one another and have openings in the profile walls.

Generally, that required for the acoustic effect communicated connections between the front and the rear microperforated cover layers either by the offset of the profiles within an element or the offset of segments to each other or through openings and / or openings in the profile walls or through Combinations of the aforementioned can be achieved.

The wall element shown in Figure 7 with the inner absorber elements 4, 5 is inherently stable and can also be used outdoors, for example as a wall element in a noise barrier. The transparent reverberant back wall 51 is formed, for example, by a 5 mm thick plastic plate, the front protection plate 52 of a 2.5 mm thick plastic plate with a perforation hole diameter 4.0 mm in an 8 × 8 mm grid. This perforation provides sufficient protection against mechanical damage to the internal absorber elements and at the same time sufficiently open area that the sound to be absorbed can pass through and strike the acoustically effective microperforated cover layers.

For outdoor use, the wall elements are in turn closed if necessary with an upper lid and have in the base discharge openings for incoming water, which are not shown in Fig. 7.

List of reference numbers

[0062] <tb> 1, 2, 3, 4, 5 <sep> sound-absorbing plate-shaped member <tb> 10, 11 <sep> topcoat <tb> 20, 21 <sep> topcoat <Tb> 30 <sep> Core <tb> 31, 32 <sep> Corrugated web profile section <tb> 33, 34 <sep> Air duct <tb> 41, 42 <sep> Corrugated web profile section <tb> 43, 44 <sep> contact area <Tb> 50 <sep> <Tb> 51 <sep> back wall <Tb> 52 <sep> Windscreen <Tb> 53 <sep> sidewall <Tb> 54 <sep> sidewall <tb> 55, 56 <sep> groove <Tb> 57 <sep> base <Tb> 58 <sep> Breakthrough <Tb> 61 <sep> Core <tb> 62, 63 <sep> breakthroughs <Tb> K <sep> contact line <Tb> M <sep> micro

Claims (15)

Sound-absorbing plate-shaped elements (1, 2), comprising a first and a second sound-absorbing cover layer (10, 20) and an inner supporting core (30, 40), characterized in that the core corrugated web profiles (31, 32, 41, 42 ), which define air channels in the plate interior and are designed and / or arranged such that the two sound-absorbing surfaces (10, 20) communicate with each other in a communicative manner. 2. Sound-absorbing plate-shaped elements (1, 2) according to claim 1, characterized in that the first and second sound-absorbing cover layer (10, 20) is provided with a micro perforation (M). 3. Sound-absorbing plate-shaped elements (1, 2) according to claim 1 or 2, characterized in that the air acts in the air channels as a spring in the manner of a Helmholtz resonator. 4. Sound-absorbing plate-shaped elements (1, 2) according to one of claims 1 to 3, characterized in that the core (30, 40) comprises at least two corrugated web profile sections (31, 32, 41, 42) offset transversely to a channel longitudinal axis or phase-shifted are arranged to each other or that at least two segments with transversely to a channel longitudinal axis offset or phase-shifted arranged corrugated web profiles are connected or assembled to form an element. 5. Sound-absorbing plate-shaped elements (1, 2) according to one of claims 1 to 4, characterized in that the corrugated web profiles are provided with openings. 6. Sound-absorbing plate-shaped elements (1, 2) according to one of claims 1 to 5, characterized in that the profile shapes of the corrugated web profiles (31, 32, 41, 42) are selected from the group of longitudinal sinusoids, trapezoidal profiles, triangular profiles or tube profiles. 7. Sound-absorbing plate-shaped elements (1, 2) according to one of claims 1 to 6, characterized in that the corrugated web profiles (31, 32, 41, 42) extend in the installed state in the vertical direction. 8. Sound-absorbing plate-shaped elements (1, 2) according to one of claims 1 to 7, characterized in that they are transparent or translucent. 9. A method for producing sound-absorbing plate-shaped elements (1, 2) comprising a first and a second sound-absorbing cover layer (10, 20) and an inner supporting core (30, 40), characterized in that for the production of the two sound-absorbing cover layers (10 , 20) plate-shaped semifinished product is microperforated in a punching process between the punch and die and then with at least one corrugated web profile (31, 32, 41, 42) is glued as a core to form a sandwich element, so that defined air channels in the plate interior and designed and / or arranged are that the sound-absorbing cover layers (10, 20) communicate with each other in a communicative manner. 10. The method according to claim 9, characterized in that for the production of the core portions of corrugated web profiles (31, 32, 41, 42) laterally offset from each other between the cover plates (10, 20) are glued. 11. The method according to claim 9, characterized in that for producing the core, a corrugated web profile is generated with laterally offset portions in a continuous manufacturing process. 12. Wall element (50) for a noise protection wall, comprising a reverberant rear wall (51), a front protective plate (52) and holding means for receiving and positionally supporting support sound absorbing elements (4, 5) according to one of the preceding claims 1 to 8 between the front protective pane (52) and the rear wall (51), wherein the protective screen (52) is preferably a transparent perforated plastic or synthetic glass pane. 13. Wall element (50) according to claim 12, characterized in that two side walls (53, 54) with vertical grooves (55, 56) for receiving and correct mounting of the sound-absorbing elements (4, 5) are provided. 14. Noise protection wall comprising sound-absorbing plate-shaped elements (1, 2) according to one of the preceding claims 1 to 8 and / or wall elements according to one of the preceding claims 12 and 13. 15. noise barrier according to claim 14, characterized in that the sound-absorbing plate-shaped elements (1, 2) are transparent or translucent and spaced from reverberant glass or plastic glass panes are arranged in the noise barrier, wherein the sound-absorbing plate-shaped elements (1,2) preferably are open at the top and bottom.