MULTI-LAYER ACOUSTIC PANEL BY KOCHETOV Russian patent published in 2015 - IPC E04B1/74 

FIELD: construction.

SUBSTANCE: multi-layer acoustic panel comprises a frame and a sound-absorbing board placed in its inner cavity. The frame is made in the form of a parallelepiped formed by front and rear walls, each "П"-shaped, with side ribs. Besides, on the walls there is slot perforation, made in the form of rectangles and arranged in rows with width of rows b₁ and b₂ and distance between them h₁ and h₂. Adjacent rows are arranged with displacement, and the number of slots in one row is even, and in the other one - odd, the perforation coefficient is accepted as equal or more than 0.25. There is a sound-absorbing board placed between front and rear walls of the frame. Walls of the panel are fixed to each other on top and bottom by vibration damping covers, which may be arranged with cells and be "П"-shaped. Front and rear walls of the frame may be made of stainless steel or galvanised sheet with thickness of 0.7 mm with a polymer protective-decorative coating of "Pural" type with thickness of 50 mcm or "Polyester" with thickness of 25 mcm, or from an aluminium sheet with thickness of 1.0 mm and with coating having thickness of 25 mcm. The sound-absorbing board comprises two perforated surfaces, between which two layers of sound-absorbing material are placed, adjoining the perforated surfaces and made of soft solid and shaped sound absorber, in which sound reflection coefficient is less than the sound absorption coefficient. Profiles of layers are formed by spherical surfaces, connected to each other so that as a whole each profile forms a solid dome-shaped profile, which focuses the reflected sound. Interrupted sound-absorbing layers arranged in focus of solid profiled layers, are made in the form of solids of revolution, for instance, in the form of balls, and are fixed with the help of rods parallel to perforated surfaces, which are stiffly connected to them by means of vertical fastening elements perpendicular to them, made, for instance, in the form of plates, one end of which is stiffly fixed on perforated planes, and the second one is made in the form of a yoke covering the rod and pulling it by a screw to the appropriate rod.

EFFECT: improved efficiency of sound suppressing.

3 cl, 2 dwg