EP0531767A1 - Device for absorption of waves - Google Patents

Abstract

Device for adsorption of acoustic and/or hydrodynamic waves, provision being made of a conical, wedge-shaped or pyramidal external circumferential surface which is constructed as a network, knitted or knotted from a weatherproof material such as rubber or glass fibre, and filled with a fibrous material. <IMAGE>

Description

The invention relates to a non-combustible, non-inflammable or flame-retardant, if necessary flexible, inexpensive to produce device for absorbing acoustic and / or hydrodynamic waves, primarily for use outside and inside closed rooms, in the environmental area and under weather conditions.

Using the technology described, modularly constructed, absorbent surfaces of any contour, permanently mounted or temporary, can be produced in any dimension with little effort and can be adapted to the requirements of the application.

The object of the invention is to provide a device for absorbing acoustic and / or hydrodynamic waves, as well as an easy-to-use method for producing the device according to the invention, which is suitable for use under weather conditions.

The device according to the invention is to be used in particular for shielding construction sites, shooting ranges, residential and recreational areas, streets and other sources of noise, and as a modular, transportable noise insulation device for use in film studios and can be installed temporarily or permanently. For use in sound film recordings, the absorber should be colorable to reduce the influence of color temperature on the surface without significantly changing the absorption behavior. Due to the corresponding adaptability to contours, the network absorber should also be usable as wall cladding for buildings.

The device should also be non-flammable and maintenance-free for the time of its use. For use in areas that are contaminated with pollutant emissions or deposits of combustion residues, as is the case, for example, when used in shooting ranges, the device should have the required chemical resistance and be washable with household, environmentally friendly methods and agents.

For the production of temporary or changeable absorption walls (for example as a curtain or mat), the absorber should be easy to transport and can be rolled up if necessary.

Devices for absorbing acoustic and / or hydrodynamic waves are known which are used in recording studios and similar facilities, predominantly for reducing the echo and the acoustic noise level. These absorbers are usually made of foams. An effective use of these absorbers under weather conditions is not possible or only possible with a significant reduction in the absorption capacity, because the absorbers absorb water through their natural porosity, which completely or partially fills a large part of the pores, especially in the surface area that is important for the absorption behavior , such as in rain or high air humidity (fog), the absorption capacity of the material is significantly reduced by the mass of the water absorbed. In addition, by the mass of water absorbed and the gravity acting thereon a deformation of the absorber profile. In addition, these absorbers are subject to considerable emissions of pollutants in the event of fire or ignition. The network absorber is used to the same extent for shielding, for example in the case of sound recordings, as for damping noise emissions.

In the environmental field, predominantly earth walls or walls are used to reduce noise, which have only a low absorption effect and only reflect the greatest proportion of the sound waves incident in another direction.

The solution according to the invention is described by several exemplary embodiments and provides to manufacture the device according to the invention, referred to in the following description as a network absorber, in that a conical, wedge-shaped or pyramid-shaped knitted or knitted or knitted or knitted or otherwise produced from a weather-resistant material Net, in the text below as a stocking, image 1, no. 1 labeled with a fiber material, Figure 2, no. 2, (for example glass fiber, mineral fiber etc.) is filled.

In order to reduce the water absorption under weather conditions, a hydrophobic behavior of the absorber material is desired, which is easily achieved permanently, for example, by silicone impregnation.

For the manufacture of mesh absorber plates, the cone shells which form the sheath of the mesh absorber cone (for example by appropriate programming of the knitting machine) are produced as an arrangement connected to the base.

Filling is also automated in a corresponding receiving device, which is injected through an injector tube, Figure 2, no. 4, for example, by stretching the mesh or opening, Figure 1, no. 1.2 in the knitting pattern of the stocking, image 1, no. 1, the mesh absorber is filled from the rear with the fiber material filling Fig. 2, Section 2.

Another possibility for the production of surface absorbers is that individual, cone-shaped stockings by knitting, knotting or in another way Figure 1, no. 1 are produced, which follow the knitting process or during the knitting process with the fiber material, Figure 2, no. 2, be filled. After the required filling quantity has been reached, the cones are knitted or knotted or sewn on the back.

Since glass fiber has very pronounced gliding properties and is only suitable for knitting to a limited extent, knitting or knotting, or the other manufacture of the carrier matrix or stockings, is used to fix the crossing points of the network knots, Figure 1, no. 1.3, knitted in or knotted or the crossing points fixed in the required grids with an adhesive.
The individual cones are connected to each other at their base, Figure 4, Section 1.1, and thus form an absorber surface, Figure 4, which is highly flexible and deformable. The surface absorber is mounted on any support plate for stabilization.
The carrier plates preferably consist of recycled glass which is foamed and cut in block form, which is laminated with glass fiber wallpaper for stabilization, or of a granulate made of foamed recycled glass in a bond of cement slurry or water glass in conjunction with, depending on the application of hydrophilic or hydrophobic aerosil, the sludges being used A foam former is added to reduce the final density.

The actual bending stability of the panels is given by the subsequent lamination with a fabric on the outer surfaces. If the stability requirements are higher, a coarse-mesh fabric is poured into the plates during manufacture.

For continuous use on road structures, the network absorbers are dimensioned larger and planted with short-growing plants if necessary. Due to the high energy absorption capacity of the interconnected absorbers, there is no risk of injury even with very intensive contact, making the system also suitable for covering boundaries at sporting events. (For example guardrail cover in motorcycle races).

If necessary, the elements of the net absorber are further stabilized in that stabilizing elements made of a coarse-mesh fabric, glass fiber, mineral fiber etc. are knitted or knotted into the interior, which, particularly in the case of long net matrices, bring about additional stabilization. The absorbers are further fastened to the envelope nets and the stabilizers by nailing, staples or other fixed or detachable fastening mechanisms on the supporting surface.

The absorption effect is achieved with the net absorber in that a carrier matrix in the form of a coarse-mesh fabric is filled with an absorbent substance, both the packing density of the absorbent substance and the composition according to the depth of penetration being able to cause an increasing degree of absorption. From the absorber cones formed in this way, a very effective surface absorber is formed by joining them together at the base, the surface of which can be penetrated with little reflection by the impinging waves.

Due to the external shape of the absorber cones, which are known from general absorption technology, particularly acoustics, the impacting wavefront is guided into the field largely free of reflections and penetrates into the labyrinth of cavities, on the walls of which the actual absorption takes place in that the Surface of the walls, which has only an inert restoring force, is deformed and the energy is converted into heat.

For example, there is the possibility of inserting a glass fiber round or profile cord, i.e. a glass fiber body, which is formed when a strand of glass floss emerges from a nozzle and can be twisted to stabilize it, or a preformed piece of glass floss Figure 3 , Section 2, with a wall and the interior of the hollow cone formed in this way with expanded glass, expanded clay or another filler Figure 3, Section. 3, replenish with absorbent effect.

However, it is also possible to knit or act on the jacket of the absorber from glass fibers and also to provide glass fibers as a filling.

The waves striking the surface of the network absorber are guided along the flanks of the absorber cones into the cavities between the fibers of the network filling and are absorbed by the deformation of the easily deformable surfaces of the absorber matrix. The fact that the proportion of the cavity resulting from the dimensions of the hosiery filling (> 90%) is large compared to the resulting proportion of the filling (<10%) ensures that penetrating rainwater flows through the network absorber without any significant residue and residual water in the network absorber can evaporate easily. A hydrophobic behavior of the absorber is caused by a Silicon impregnation of the filling compound or the absorber surface achieved after completion.

The use of the device for noise reduction at shooting ranges, to reduce the impairment of living habits of residents is possible in a simple manner, also by temporarily cladding walls, absorber boxes, shot channels, screens, etc., to reduce the noise emissions of the shooting range, especially in the vicinity Residential areas, reduce. At the same time, the effect of the muzzle blast on neighboring shooters is reduced by reducing the reflection of the sound waves even in shooting ranges with several adjacent firing positions.

When firing a shot, a distinction must be made between the muzzle blast, which is formed by the excess gas depending on the design of the pipe muzzle (fire damper), and the bullet bang, which occurs along the trajectory of the projectile when the bullet speed is above the speed of sound.

In order to further reduce the risk of ricochets forming when the absorber units are bombarded and to minimize the costs for the production, the absorber material is introduced into hollow or basket-shaped hollow bodies which are made from an elastomer or from rubber. The manufacturing processes used in elastomer or rubber processing allow the production of net or basket-shaped arrangements of any contour, as well as their easy removal from the mold during manufacture.

Figure 1 shows such an arrangement, in which the support structure is made in one operation from a rubber or elastomer material, which due to its natural damping properties and the high degree of deformability when striking acoustic Vibrations are deformed and the filling made of absorber material returns to its original contour. By using the aforementioned materials, it is possible to form a tip on the individual absorber cones, which has an extremely small reflection cross section and guides the incident wave into the depth of the absorber structure.

An embodiment of the support structure with higher stability provides for a network of fiber material, e.g. To manufacture glass fiber cord and to cover this structure in whole or in part with a covering or stabilizing ribs made of rubber or elastomer.

The support structures are mounted on a net (e.g. made of stabilized glass fiber fabric) using clips or other known connection techniques.

The absorption tips are preferably filled in the state mounted on the support structure by means of an arrangement as shown in Figure 5. This arrangement consists of an injector nozzle which is passed through the mesh of the network and, by means of the injected air flow, causes the filler to be conveyed, through which the filler is conveyed into the interior of the cone.

Another cost-effective version of the carrier body consists in molding a insert made of coarse-mesh fiber fabric into a stabilizing frame made of rubber or elastomer that connects the tapered lines on the corner lines and which is inserted as a blank into the injection or vulcanizing mold. The connection at the corner points is formed by the rubber or elastomer structure vulcanized around the network boundaries.

As a carrier plate for the manufacture of silencer boxes, preferably with water glass, cement slurry or Polyurethane foam-bound mixture with a filling made of expanded glass (foamed recycling glass) is used, which is laminated on the outside for stabilization. A fabric is particularly suitable for lamination, for example made of glass fiber (glass fiber wallpaper), which is glued to the plate. The lamination is advantageously carried out with the production of the plate shape in one work step and thereby forms a sandwich plate with high bending stiffness, which can be penetrated without significant floor deflection.

Absorber boxes for temporary use in shooting ranges are mounted on a frame that can be moved on guide rails if required and stored inside the building. The required number of boxes are put into use.

Since nitrous gases can be generated when firing with modern propellants, the absorber boxes, preferably in the corner edges of the inner sides which are not completely covered with absorbers, are provided with suction devices which are realized by perforated or slotted pipes.

Claims (9)

Device for absorbing acoustic and / or hydrodynamic waves, characterized in that a conical, wedge or pyramid-shaped outer jacket is provided, which is knitted, knotted or knitted from a weather-resistant material and which is filled with a fiber material. Apparatus according to claim 1, characterized in that the reticular outer casing and the filler material are hydrophobically coated or equipped. Apparatus according to claim 1 or 2, characterized in that a silicone impregnation is provided at least on the absorber surface. Apparatus according to claim 1, 2 or 3, characterized in that a plurality of cone-shaped absorber networks are connected to one another at their base to form a surface absorber. Device according to one of the preceding claims, characterized in that a round or profile cord formed from fibers, preferably glass fibers, is spirally introduced into the absorber jacket. Device according to one of the preceding claims, characterized in that the absorber jacket is formed from fibers, preferably glass fibers, in a coarse mesh. Apparatus according to claim 5 or 6, characterized in that the cavity formed by the spirally introduced cord or the absorber jacket with an absorbent filler such as expanded glass, expanded clay or the like. is filled out. Device according to one of the preceding claims, characterized in that the absorber is filled with fibers, for example glass fibers or mineral fibers. Device according to one of the preceding claims, characterized in that the network structures of the absorber jacket are connected to one another at the crossing points by means of knots or adhesive points or the like.

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