COMBINED-TYPE KOCHETOV SOUND ABSORBER Russian patent published in 2016 - IPC E04B1/84 

FIELD: acoustics.

SUBSTANCE: invention relates to means of reducing noise in industrial and transport facilities. Single acoustic absorber of combined type comprises active and reactive acoustic absorbers located on a rigid frame. Frame is made of two parts. Bottom reactive part is made as a rigid hollow structure of cylinder-conic shape. Upper active part is made in the form of a rigid perforated cylindrical shell with a perforated cover and a solid base. Cavity of cylindrical shell is filled with sound absorbing material. Upper and the lower parts are connected with a resilient damping element ensuring dampening of HF oscillations. To perforated cover perforated cylindrical shell is pivotally mounted element, using which frame is attached to required object, for example ceiling of production room. Around perforated cylindrical shell there is at least one screw-type sound absorbing element, in form of cylindrical coil spring enclosing the shell. In bottom, reactive part of carcass cylindrical part is hollow in the form of Helmholtz resonance silencer with resonator necks of different diameter, located in cover and base of hollow cylinder, as well as on its side surface. Cavity of conical part represents Helmholtz resonator with neck located in base of cylinder. Screw sound absorbing element is made in form of hollow screw sound absorbing element, formed by outer and inner screw surfaces forming cavity. Space formed by outer and inner screw surfaces, is filled with sound absorbing material with density lower than that of screw sound absorbing element. Cavity of screw sound absorbing element formed by its outer and inner screw surfaces, is filled with sound absorbing material from mineral wool on basalt base of “Rockwool” type, or from "URSA" mineral wool, or P-75 basalt wool, or glass wool with glass felt. Sound absorbing material over its entire surface is lined with an acoustically transparent material, for example, EZ-100 glass fabric or "poviden" type polymer. Outer and inner screw surfaces of screw sound absorbing element made from material based on aluminium containing alloys followed by titanium hydride or air with density within 0.5…0.9 kg/m³ with following strength properties: compression strength within 5…10 MPa, bending strength within 10…20 MPa, for example foamed aluminium.

EFFECT: invention ensures higher efficiency of noise suppression at high frequencies.

1 cl, 1 dwg