SOUND ABSORBING STRUCTURE Russian patent published in 2018 - IPC E04B1/84 F01N1/04 

FIELD: acoustics.

SUBSTANCE: invention relates to industrial acoustics. Technical result is achieved by the fact that the sound absorbing element is made in form of external and internal perforated walls, between which acoustic absorber is placed, consisting of three layers of sound-absorbing material, the first layer, more rigid, is solid and profiled and fixed at the internal surface, and the second layer is softer than first one and is intermittent and placed in focus of sound reflecting surfaces of first layer, wherein first layer is more rigid, solid and made profiled, and the second layer, softer than first, is discontinuous and placed in focus of sound reflecting surfaces of first layer, and third layer of sound-absorbing element is made from foamed sound absorbing material, for example a construction sealing foam, and places between the firs, more rigid, layer and the perforated surface of the sound-absorbing element, discontinuous sound absorbing layer located in focus of a solid shaped layer is made in the form of rotation bodies, for example in the form of balls, and attached by means of rods parallel to upper and lower perforated surfaces, which are rigidly attached to each other by means of vertical fasteners perpendicular to them, for example in the form of plates, one end of which is rigidly fixed on the upper perforated surface, and the other one is made in the form of a clamp enveloping the rod and tightening it by means of a screw, solid shaped layer of sound-absorbing element is made of more rigid sound-absorbing material, in which sound reflection factor higher than that of sound absorption, wherein sections are formed by spherical surfaces, connected to each other so that in each profile creates solid dome profile, focusing reflected sound on same soft discontinuous sound absorbing layer, Intermittent sound-absorbing layer located in focus of solid profiled layer, comprises at least one rigid resonant shell with resonant holes serving as the neck of the Helmholtz resonators, wherein the cavity of the shell is an additional volume of Helmholtz resonators.

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

1 cl, 1 dwg