SOUND-ABSORBING STRUCTURE OF INDUSTRIAL PREMISES Russian patent published in 2016 - IPC E04B1/82 G10K11/16 

FIELD: acoustics.

SUBSTANCE: invention relates to industrial acoustics, particularly, to broadband acoustic suppression, and can be used in all industries when noise-proofing production equipment. Sound-absorbing structure of industrial facility comprises a plant frame, window and door openings, openings for placement of lamps, acoustic enclosures and sound absorber elements. Acoustic enclosures are made in form of smooth and perforated walls, between which there is a sound-absorbing material arranged in two layers, one of which is harder, continuous and profiled, and other is soft, discontinuous and placed in focus of sound reflecting surfaces of first layer. Solid shaped layer of sound-absorbing material is made from material with sound reflection factor higher than that of sound absorption. Profiles are formed by spherical surfaces, connected to each other so that in each profile creates solid dome profile, focusing reflected sound on same soft acoustic absorber, which is located in focus of solid profiled layer made in form of solids of revolution, for example in form of spheres, and is attached by means of rods parallel to perforated wall and rigidly connected with smooth wall by vertical links. Sound absorber consists of a rigid frame, which contains a cover with circular collars for fixing cylindrical bushing. Covers are joined with a central rod equipped with hooks on both ends. Cylinder bushing includes two perforated shells - external and internal - space between which is filled with sound absorber. Outside perforated cylindrical bushing there is a layer of acoustically transparent shell made from capronic net or glass fabric. Sound-absorbing material placed in inner cavity of sound absorber is made of unwinding roll, one end of which is rigidly fixed on central rod, and free end rests against inner shell to form in cross-section perpendicular to rod, a closed shape in form of Archimedean spiral with increasing from centre to periphery air gaps (not shown in drawing), wherein it has higher porosity in comparison to sound absorber located inside shells. Covers have outer surfaces of fairings of conical shape. Sound absorbing structure is additionally equipped with acoustic suspended ceiling, which consists of a rigid frame suspended to ceiling of factory building with located inside frame sound absorbing structure of sound-absorbing material wrapped with acoustic transparent material. Perforated sheet is attached to frame. Frame is made in form of a rectangular parallelepiped with dimensions of sides in plan a×b, ratio of which is within optimal range of values a:b = 1:1…2:1, as well as optimum ratio of dimensions c:d = 0.1…0.5; where d is distance from suspension point of frame to any of its sides; c is thickness of layer of sound-absorbing material. Frame elements are attached to each other by means of brackets rigidly connected to rod, which are connected to suspensions. Perforated sheet has following perforation parameters: perforation diameter 3…7 mm, perforation percentage 10 %…15 %. Lamps are mounted in frame. Sound-absorbing material of first, more rigid, ply of a material based on aluminium-containing alloys with subsequent titanium hydride or air with density within range of 0.5…0.9 kg/m³ with following strength properties: compression strength within range of 5…10 MPa, bending strength within range of 10…20 MPa, for example foam aluminium. Sound-absorbing material of second, softer layer used mineral wool on basalt base Rockwool or URSA mineral wool or P-75 basalt wool or glass wool lined with glass felt, or foamed polymer, for example, polyethylene or polypropylene. Perforated wall is made of solid decorative vibration-damping materials, for example plastic such as "Agat" "Antivibrit", "Shvim". Inner surface of perforated wall facing sound-absorbing material, lined with acoustically transparent material, for example, glass fabric EZ-100 or polymer of "Poviden" type.

EFFECT: higher efficiency of noise absorption by expanding frequency range and secondary absorption of sound waves reflected from sound absorber.

1 cl, 4 dwg