SINGLE PIECE SPHERICAL SOUND ABSORBER FOR MOBILE VEHICLES Russian patent published in 2018 - IPC E04B1/84 G10K11/16 

FIELD: acoustics.

SUBSTANCE: invention relates to means of reducing noise in industrial and transport facilities. Device comprises located on the rigid frame active and reactive type sound absorbers. Frame is made of two parts. Bottom reactive part is made in form of structure of spherical shape with internal congruent spherical resonant cavity formed by rigid spherical enclosure equidistant outer perforated spherical shell connected with top active part, which is made in form of rigid perforated cylindrical shell with perforated cover and solid base. Cylindrical shell cavity is filled with the sound-absorbing material. Upper and lower parts connection is made by means of resilient damping element. Spherical resonance cavity is rigidly connected by at least one bushing with axial bore acting as the Helmholtz resonator neck with external perforated spherical enclosure. Space between them is filled with sound absorber. Around the perforated cylindrical shell helical sound-absorbing element in the form of covering the shell cylindrical helical spring is arranged. As the sound absorbing material, the heat-resistant, highly porous fibrous heat-insulating and sound absorbing material is used, made of mineral filler in the form of silica fibers, binder, sintering additive, in the capacity of which amorphous boron or boron nitride are used, and surfactant. As the silica fibers silica fiber having diameter of 4–10 mvcm is used, as the binder and simultaneously as the surfactant, aqueous solution one of the substances selected from a group comprising methylcellulose, carboxymethylcellulose or carboxymethyl starch.

EFFECT: increase in the noise suppression at high frequencies efficiency.

1 cl, 1 dwg