ACOUSTIC ENCLOSURE Russian patent published in 2018 - IPC E04B1/84 

FIELD: acoustics.

SUBSTANCE: invention relates to the industrial acoustics, particularly, to the broadband noise suppression, and can be used in all branches of the national economy in noise suppression of production equipment by sound absorption method. Acoustic barrier contains a smooth and perforated surfaces, between which a multi-layer sound absorbing structure is arranged. It is made in the form of rigid and perforated walls, between which there are two layers: a sound-reflecting layer, adjacent to the rigid wall, and a sound-absorbing layer adjacent to the perforated wall. Layer of sound reflecting material has a complex profile, consisting of evenly distributed hollow tetrahedrons, which enable to reflect sound waves coming in all directions. Perforated wall has following perforation parameters: holes diameter – 3÷7 mm, perforation percentage is 10÷15 %, and the holes can be made in the form of holes of round, triangular, square, rectangular or diamond-shaped profile, wherein in case of non-circular holes, the maximum diameter of circle inscribed into a polygon shall be considered as a nominal diameter. As the sound-absorbing material, basalt-based “Rockwool” type mineral wool is used, or mineral wool of the "URSA" type, or basalt wool of P-75 type, or glass wool lined with glass felt, or foamed polymer, for example polyethylene or polypropylene. Fibrous sound absorbers surface is treated with special air permeable porous paints, for example, "Acutex T", or covered with air-permeable fabrics or non-woven materials, for example "Lutrasil".

EFFECT: technical result consists in increasing the efficiency of noise absorption by expanding the frequency range and secondary absorption of sound waves reflected from the sound absorber.

1 cl, 3 dwg