KOCHETOV SOUND-ABSORBING SPIRAL STRUCTURE Russian patent published in 2016 - IPC E04B1/99 

FIELD: acoustics.

SUBSTANCE: invention relates to industrial acoustics. Sound absorbing element made in the form of external and internal perforated walls, between which acoustic absorber is placed, consisting of three layers of sound-absorbing material, wherein first layer is more rigid, solid and made profiled and is fixed on the outer surface, second layer is softer than the first one and is intermittent and is placed in focus of sound reflecting surfaces of the first layer, wherein first layer is more rigid, solid and made profiled, and second layer is softer than the first one and is intermittent and placed in focus of sound reflecting surfaces of the first layer, and third layer of sound-absorbing element is made of foamed sound absorbing material, for example, construction sealing foam, and is located between the first, more rigid layer, and perforated surface of sound absorbing element, intermittent sound-absorbing layer located in focus of solid profiled layer is made in form of bodies of rotation, for example in form of balls, ellipsoids of rotation and is attached by means of rods parallel to perforated surfaces, which are rigidly connected to each other by means of vertical fasteners perpendicular to them, for example, in form of plates, one end of which is rigidly fixed on a smooth surface and the other is made in form of clamp enclosing the rod and tightening it with screw.

EFFECT: technical result - increase of efficiency of noise suppression at low and medium frequencies.

1 cl, 1 dwg