SOUND ABSORBER Russian patent published in 2018 - IPC F01N1/04 

FIELD: acoustics.

SUBSTANCE: invention relates to noise suppression. Sound absorber contains a frame made in the form of two outer walls: one of which is solid and the other is perforated, and the inner, middle wall is made in the form of a membrane resonant plate, between which there are layers of sound-absorbing material, wherein the frame is symmetric with respect to the middle wall, which divides it into two congruent parts, each of which has three layers of sound-absorbing material, and more rigid, first layers are made solid, profiled and fixed respectively on the outer perforated walls, second layers, softer than the first ones, are made intermittent and located with a gap in the focus of the sound reflecting surfaces of the first layers, the second layers have a rotation body shape in the form of cones connected by bases, and the first layers are made of a material with a sound reflecting coefficient greater than its sound absorption coefficient in the form of profiles of conical surfaces that focus the reflected sound on the second layers, and the third sound-absorbing layers are made of foamed sound-absorbing material in the form of a construction sealing foam and are located in gaps and voids formed between the first and second layers, wherein each of the outer perforated walls is rigidly connected to the corresponding second layer by means of vertical fastening elements perpendicular thereto, made in the form of plates, one end of which is rigidly fixed on outer perforated wall, and the second end is made in the form of clamps covering the rods respectively and tightening them with screws, while the rods are made parallel to the perforated walls, and the middle wall, made in the form of a membrane resonance plate, is rigidly connected to the frame by means of a construction sealing foam located in the gaps and voids of the frame.

EFFECT: higher efficiency of soundproofing at low and medium frequencies.

5 cl, 2 dwg