ACOUSTIC DEVICE Russian patent published in 2018 - IPC E04B1/84 G10K11/16 

FIELD: acoustics.

SUBSTANCE: invention relates to industrial acoustics, in particular to broadband and low-frequency noise attenuation, and can be used in all branches of the national economy with sound attenuation of production equipment by sound absorption method. Acoustic device consists of at least two sound-absorbing sections, each of which contains walls of corrugated perforated material, between which there are sound-absorbing elements. Walls of the corrugated material are made with slotted perforations made of stainless steel or galvanized sheet with a thickness of 0.7 mm with polymeric protective and decorative coating of "Pural" type (50 mcm thick) or "Polyester" (25 mcm thick), or aluminum sheet with a thickness of 1.0 mm and a coating thickness of 25 mcm. Sound absorbing sections are suspended on ropes by hooks. Each of the sound-absorbing elements is made in the form of two perforated surfaces, between which layers of sound-absorbing material are placed. First layer is more rigid, solid and profiled and is fixed on outer surface. Second layer, softer than the first one, is made intermittent and is located in the focus of the reflecting surfaces of the first layer. Third layer of sound-absorbing element is made of foamed sound absorbing material, for example a construction sealing foam, and is located between the first, more rigid layer and the perforated surface of the sound-absorbing element. Intermittent sound-absorbing layer, located in the focus of a solid profiled layer, is made in the form of bodies of revolution, for example in the form of balls, ellipsoids of rotation, and fixed by means of rods parallel to the perforated surfaces, which are rigidly connected among themselves by means of vertical, perpendicular to them, fastening elements, for example in the form of plates, one end of which is rigidly fixed on a smooth surface, and the second is made in the form of a clamp, covering the rod and tightening it with a screw. Continuous profiled layer is made of a more rigid sound-absorbing material, in which the reflection coefficient of sound is larger than the sound absorption coefficient. Profiles are formed by spherical surfaces, connected together so that in general each of the profiles forms a solid domed profile that focuses the reflected sound on the same soft intermittent sound-absorbing layer. Intermittent sound-absorbing layer located in focus of solid profiled layer, is made in the form of bodies of revolution, for example in the form of balls, and rigid resonant shells with resonant holes that perform the functions of the neck of the Helmholtz resonators, while the resonance holes are of different diameters to absorb sound energy over a wide frequency range.

EFFECT: invention improves acoustic characteristics at low, medium and high frequencies with provision of dust repulsion.

4 cl, 4 dwg