SOUND-ABSORBING ANNULAR STRUCTURE BY KOCHETOV Russian patent published in 2016 - IPC E04B1/84 

FIELD: acoustics.

SUBSTANCE: invention relates to industrial acoustics. Sound-absorbing annular structure is made in form of ring, which walls in axial cross section are made in form of outer and inner perforated surfaces. Between perforated surfaces sound absorber is arranged, consisting of three layers of sound-absorbing material. First layer, more rigid, is made solid and shaped and fixed on outer surface. Second layer, softer, than first one, is made discontinuous, is placed in focus of first layer sound reflecting surfaces and has shape of revolution bodies in form of balls and ellipsoids of revolution. First layer is made from material with sound reflection coefficient, larger, than its sound absorption coefficient in form of spherical surfaces profiles, connected to each other with formation of solid dome-shaped profile, focusing reflected sound on second layer. Second layer is fixed by means of rods, parallel to perforated walls. Third sound absorbing layer is made from foamed sound absorbing material in form of construction sealing foam, and is located in voids, formed between first and second layers. External perforated wall is rigidly connected to second layer by perpendicular to it vertical securing elements in form of plates, one end of which is rigidly fixed on external perforated wall, and second end is made in form of clamp, enclosing rod, and tightening it screw.

EFFECT: invention enables to increase noise suppression efficiency at low and medium frequencies.

1 cl, 1 dwg