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Axial-Flow Air Fan Silencer

IP.com Disclosure Number: IPCOM000038566D
Original Publication Date: 1987-Feb-01
Included in the Prior Art Database: 2005-Jan-31
Document File: 2 page(s) / 53K

Publishing Venue

IBM

Related People

Gaunt, DS: AUTHOR

Abstract

A silencer for an axial-flow air fan comprises an air exhaust duct into one end of which the fan feeds air, and which includes an enclosed resonant cavity having an exchangeable apertured plate between it and the air passage in the duct. A machinery container 1 has an endwall 2 through which is formed an exhaust hole 3 for air circulated by an axial-flow air fan (not shown). Upon the wall 2 is secured an air exhaust duct 4 into which the hole 3 feeds exhausted air. The duct 4 is an open-sided box and supports a central dividing wall 5 of which the portion opposite the hole 3 is of foamed plastic construction to absorb and restrain vibrations in the air entering the duct 4.

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Axial-Flow Air Fan Silencer

A silencer for an axial-flow air fan comprises an air exhaust duct into one end of which the fan feeds air, and which includes an enclosed resonant cavity having an exchangeable apertured plate between it and the air passage in the duct. A machinery container 1 has an endwall 2 through which is formed an exhaust hole 3 for air circulated by an axial-flow air fan (not shown). Upon the wall 2 is secured an air exhaust duct 4 into which the hole 3 feeds exhausted air. The duct 4 is an open-sided box and supports a central dividing wall 5 of which the portion opposite the hole 3 is of foamed plastic construction to absorb and restrain vibrations in the air entering the duct 4. Alongside the portion of the duct 4 through which the air flow is straight to the exit, the central wall 5 has an apertured portion 6 with apertures 7 leading into an enclosed cavity 8 formed by the duct 4 and an end plate 9. A resistive pad 10 of sound-absorbing material is mounted on the wall portion 6 within the cavity 8. In use, annoying prominent low frequency tones generated by the axial-flow air fan are reduced to an acceptable level by attenuation in the cavity and high frequency tones reduced by the foamed plastic portion of the wall 5. At resonance, the transmission loss of the device is governed by the resonator resistance which is proportional to the flow resistance of the aperture plate holes. This flow resistance is controlled by the flow resistance of...