SOUND ABSORBING ELEMENT Russian patent published in 2016 - IPC E04B1/84 G10K11/16 

FIELD: acoustics.

SUBSTANCE: invention can be used for machine drive noise reduction, lining of manufacturing facilities and in other sound-absorbing structures. Sound absorbing element comprises a smooth and perforated surface between which a multilayer sound absorbing structure is made as rigid and perforated walls, between which there are layers of sound reflecting and sound-absorbing materials of different density arranged in two layers. Layers of sound reflecting material have a complex profile consisting of evenly distributed hollow tetrahedrons, which allow to reflect sound waves coming in all directions, and which are located near rigid and perforated walls, respectively. Layers of sound reflecting material are made from heat-insulating material able to maintain preset microclimate in room. Sound-absorbing material used is soundproof sheet material, which is based on magnesite binder with reinforcing glass or glass, or polyester, or porous sound-absorbing ceramic material with volume density 500÷1,000 kg/m³, and consisting of 100 pts.wt pearlite with grain diameter of 0.1÷8.0 mm, 80÷250 pts.wt of one of sintering materials selected from a group comprising ash dust, slag, quartz, lava, stones or clay as main material, 5÷30 pts.wt inorganic binder, wherein after sintering mixture of pearlite particles form communicating holes between contact surfaces so that inner pores are interconnected. Uses as sound reflecting material there is a material based on aluminium-containing alloys with subsequent filling of them with titanium hydride or air with density of 0.5…0.9 kg/m³ having the following strength properties: compression strength within 5…10 MPa, bending strength within 10…20 MPa, for example, foam aluminium, or sound insulating plates on the basis of glass staple fibre of “Shumostop” type with density of material equal to 60÷80 kg/m³. Perforated wall can be made of structural materials with, applied on their surface on one or two sides, layer of soft vibration dampening material, for example of VD-17, or paste material of “Gerlen-D” type. Ratio between thickness of material and vibration damping coating is within optimal range of values: 1/(2.5…3.5), or of stainless steel, or a galvanised steel sheet with thickness of 0.7 mm with a polymer protective-decorative coating such as “Pural” with thickness of 50 mcm or “polyester” with thickness of 25 mcm, or aluminum sheet with thickness of 1.0 mm and thickness of coating of 25 mcm, or from solid, decorative damping materials, for example, elastrons “Agat”, “Antivibrit”, “Schwim”. Inner surface of perforated surface facing sound-absorbing structure is lined with acoustically transparent non-woven material, for example Lutrasil.

EFFECT: invention allows to improve efficiency of sound absorption and reliability of the structure on the whole.

3 cl, 1 dwg, 1 tbl