NOISE SUPPRESSOR FOR THE AXIAL FAN Russian patent published in 2018 - IPC F01N1/04 F01N1/24 

FIELD: ventilation.

SUBSTANCE: noise suppressor for the axial fan comprises a housing coaxial inlet and outlet nozzles and a resonant insert mounted coaxially to the housing. Housing and the resonant insert are placed coaxially and have an equidistant circular or polygon profile. Resonant insert along the edges is equipped with a diffuser and a confuser with perforated disks rigidly attached to them. In the middle of the resonant insert is a sound absorber mounted, separating the resonant insert into two chambers. Resonant insert is fixed in the housing by means of fixing elements made in the form of at least one partition with holes. Housing on the inside, and the resonant insert on the outside are lined with sound absorbing material having thickness h₁ and h₂, respectively. Housing and the resonant insert are made of structural materials with a layer of soft vibration damping material applied to their surfaces from one or both sides, for example VD-17 mastic, or a material such as "Gerlen-D". Ratio between the thickness of the housing and the vibration damping coating lies in the optimal range of values – 1:(2.5…3.5). Sound absorber, installed in the resonant insert, is made in the form of two external perforated walls with a sound-absorbing element inside.

EFFECT: efficiency of the noise suppression increases with the use of the invention.

5 cl, 2 dwg