COMBINED KOCHETOV NOISE SUPPRESSOR Russian patent published in 2016 - IPC F01N1/04 E04B1/84 

FIELD: acoustics.

SUBSTANCE: invention relates to noise suppression. Combined noise suppressor contains cylindrical housing, rigidly connected with end inlet and outlet nozzles, which diameter is not less than housing diameter, and sound-absorbing cylindrical insert, arranged along silencer axis. On each of perforated cylindrical insert end sides fairing of conical shape is fixed. Cylindrical insert is fixed to housing by means of at least two stiffening ribs, located in plane perpendicular to silencer axis, wherein cylindrical insert outer surface is made perforated, and sound absorber and acoustically transparent material are located inside insert. Sound-absorbing cylindrical insert is made hollow and in axial cross section is made in form of rigid and perforated walls, between which two layers are arranged: sound-reflecting layer, adjacent to rigid wall, and sound-absorbing layer, adjacent to perforated wall. Layer of sound reflecting material is made with complex profile, composed of evenly distributed hollow tetrahedrons, which enable to reflect sound waves incoming from all directions. Perforated wall has following perforation parameters: holes diameter - 3÷7 mm, perforation percentage 10÷15 %, wherein by form holes can be of circular, triangular, square, rectangular or rhomboid profile. In case of non-circular holes, it is necessary to consider as nominal diameter maximum diameter of circle inscribed in polygon. Sound-absorbing material used is mineral wool on basalt base of “Rockwool” type, or "URSA" type mineral wool, or basalt wool of P-75 type, or glass wool lined with glass felt, or foamed polymer, for example, polyethylene or polypropylene. Fibrous sound absorbers surface is treated with special porous paints, passing air (for example, “Acutex T”), or coated with air-permeable fabrics or nonwoven materials, for example, “Lutrasil”.

EFFECT: invention allows to improve efficiency of noise suppression.

1 cl, 3 dwg