HELICAL-TYPE KOCHETOV SOUND ABSORBING ELEMENT Russian patent published in 2016 - IPC E04B1/84 

FIELD: acoustics.

SUBSTANCE: invention relates to industrial acoustics. Sound absorbing element comprises smooth and perforated surfaces, between which multilayer sound absorbing structure is arranged, which is made in two layers: sound-reflecting layer, adjacent to rigid wall, and sound-absorbing layer, adjacent to perforated wall. Layer of sound reflecting material is made with complex profile, composed of evenly distributed hollow tetrahedrons, which enable to reflect sound waves incoming from all directions. Perforated wall has the following perforation characteristics: aperture diameter 3÷7 mm, perforation percentage is 10÷15%, wherein holes can be made in form of circular, triangular, square, rectangular or rhomboid shape. In case of non-circular holes, it is necessary to consider as nominal diameter maximum diameter of circle inscribed in polygon. Sound-absorbing material used is mineral wool on basalt base of “Rockwool” type, or "URSA" type mineral wool, or basalt wool of P-75 type, or glass wool lined with glass felt, or foamed polymer, for example, polyethylene or polypropylene, wherein fibrous sound absorbers surface is treated with special porous paints, passing air (for example, “Acutex T”), or coated with air-permeable fabrics or nonwoven materials, for example, “Lutrasil”.

EFFECT: invention allows to improve efficiency of sound absorption and reliability of the structure on the whole.

3 cl, 1 dwg