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Browse Prior Art Database

Muffler

IP.com Disclosure Number: IPCOM000093653D
Original Publication Date: 1966-Jan-01
Included in the Prior Art Database: 2005-Mar-06
Document File: 2 page(s) / 37K

Publishing Venue

IBM

Related People

Engstrom, JR: AUTHOR [+2]

Abstract

Attenuation of a broad band of sound pressure frequencies is accomplished by mounting cylindrical chamber 1 eccentrically in pressure duct 2. Chamber 1 acts as a large number of side branch tubes, each formed to attenuate a single frequency. The chamber 1 eccentricity is determined by the frequency band to be muffled. Since a cancelling phase shift of the air-borne pressure occurs when the cavity depth is one-quarter of the attenuated wave length, the radial depth a of the cavity can vary from a quarter wave-length of the high band frequency to a depth b that is a quarter wave-length of the low band frequency. However, a limitation of cavity construction is that in no case can cavity depth at one point be twice the depth at another point because a half wave-length cavity produces amplification.

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Muffler

Attenuation of a broad band of sound pressure frequencies is accomplished by mounting cylindrical chamber 1 eccentrically in pressure duct 2. Chamber 1 acts as a large number of side branch tubes, each formed to attenuate a single frequency. The chamber 1 eccentricity is determined by the frequency band to be muffled. Since a cancelling phase shift of the air-borne pressure occurs when the cavity depth is one-quarter of the attenuated wave length, the radial depth a of the cavity can vary from a quarter wave-length of the high band frequency to a depth b that is a quarter wave-length of the low band frequency. However, a limitation of cavity construction is that in no case can cavity depth at one point be twice the depth at another point because a half wave-length cavity produces amplification.

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