COMBINED ACOUSTIC ABSORBER BY KOCHETOV Russian patent published in 2015 - IPC E04B1/84 F16F15/04 

FIELD: machine building.

SUBSTANCE: acoustic absorber of combined type comprises active and reactive acoustic absorbers located on a rigid frame, the frame is made out of two parts. The bottom reactive part is made as a rigid, hollow structure of cylindrical shape with a cavity, and the top active part is made as a rigid perforated cylindrical shell with perforated cover and solid base. The cavity of the cylindrical shell is filled with sound absorbing material, and the connection between the top and bottom parts is made by means of a resilient damping element ensuring damping of HF oscillations. An element is pivotally connected to the perforated cover of the perforated cylindrical shell, it helps the frame to be fixed to the required structure, for example, the ceiling of production premises; the cavity of the frame's reactive part is connected to the holes of different diameter serving as necks of Helmholtz resonator. The holes are provided in the cover, the base and on the side surface of the hollow cylinder, the inner walls of the bottom reactive part of the cylindrical hollow frame are rigid, and the outer walls are perforated. The space between them is filled by acoustic absorber, around the perforated cylindrical shell there is at least one screw acoustic absorbing element in the form of a cylindrical coil spring enclosing the shell.

EFFECT: improved efficiency of noise suppression at high frequencies.

2 cl, 1 dwg