PERFORATED RING TYPE SOUND ABSORBING ELEMENT Russian patent published in 2018 - IPC E04B1/84 G10K11/16 

FIELD: acoustics.

SUBSTANCE: invention relates to the industrial acoustics. Perforated ring-type sound-absorbing element contains a smooth and perforated surface between which a multi-layered sound absorbing structure is placed, while in the axial section it is made in the form of a ring, the walls of which are made in the form of a rigid and perforated walls, between which there are two layers: a sound-reflecting layer adjacent to the rigid wall and an acoustic-absorbing layer adjacent to the perforated wall, the layer of sound reflecting material is made of a complex profile consisting of uniformly distributed hollow tetrahedra that allow to reflect the sound waves falling in all directions, and the perforated wall has the following perforation parameters: diameter of holes 3÷7 mm, percent perforation 10÷15 %, and in the form of holes can be made in the form of openings of a round, triangular, square, rectangular or diamond-shaped profile, at that, in case of non-circular holes, as the conditional diameter the inscribed in the polygon circle maximum diameter should be considered, the sound-absorbing material used is a porous sound-absorbing ceramic material having a bulk density of 500÷1,000 kg/m, and consisting of 100 parts by weight of perlite with a particle diameter of 0.5÷2.0 mm, 100÷200 parts by weight of one or more sintering materials and 10÷20 parts by weight of binders, while as a sound-reflecting material, a material based on a magnesia binder with a reinforcing fiberglass or glass fiber can be used, layer adjacent to the perforated wall is made with a perforation from a sound-reflecting material of a complex profile consisting of uniformly distributed hollow tetrahedra.

EFFECT: technical result is the increase in the efficiency of acoustic suppression and reliability of the structure in general.

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