초록 ▼

Apparatus for attentuating noise emitted from an inlet port to a centrifugal fan comprises a panel member which is mounted in spaced confronting relationship to the inlet port and includes a rigid backing member, a facing mounted in spaced disposition from the rigid backing member, partitions dividi

Apparatus for attentuating noise emitted from an inlet port to a centrifugal fan comprises a panel member which is mounted in spaced confronting relationship to the inlet port and includes a rigid backing member, a facing mounted in spaced disposition from the rigid backing member, partitions dividing the space between the rigid backing member and the facing into a plurality of cavities, and acoustic infill in the cavities. The facing has a plurality of perforation zones, and is formed in each perforation zone with small perforations whereby the facing is rendered acoustically permeable over a limited area only. One wall of each cavity includes a perforation zone of the facing, whereby the cavities constitute Helmholtz absorption cavities. The facing is adapted to face the inlet port and transmit noise for attenuation in the cavities.

대표청구항 ▼

Apparatus for attenuating noise emitted from an inlet port to a centrifugal fan, and comprising a panel member adapted to be mounted in spaced confronting relationship to said inlet port, said panel member including (a) a rigid backing member, (b) a perforated, acoustically permeable facing mounted

Apparatus for attenuating noise emitted from an inlet port to a centrifugal fan, and comprising a panel member adapted to be mounted in spaced confronting relationship to said inlet port, said panel member including (a) a rigid backing member, (b) a perforated, acoustically permeable facing mounted in spaced disposition from said rigid backing member and adapted to face said inlet port, (c) wall means dividing the space between said rigid backing member and said facing into a plurality of Helmholtz absorption cavities, said facing providing a small area of perforation for each of said cavities for transmitting noise into said cavities, at least a substantial portion of said cavities being dimensioned to have resonant frequencies in the range of about 30 Hz to 250 Hz, and (d) acoustic infill in the absorption cavities between said rigid backing member and said facing, whereby said apparatus has a high degree of attenuation in the range of about 30 Hz to 250 Hz.