The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Feb. 01, 1983
Filed:
Dec. 21, 1979
Leslie S Wirt, Newhall, CA (US);
Lockheed Corporation, Burbank, CA (US);
Abstract
An acoustical silencer for a gas passage or exhaust duct for a gas turbine engine, which is composed of three parts. The first comprises an absorptive surface to absorb incident low frequency sound the second comprises an acoustically lined duct attenuating high frequency sound transmitted therethrough. The entrance to the first part and the entrance to the second part are essentially coplanar. The third part is a horn-shaped plenum or conical diffuser to contain the flow and distribute the sound over the entry surface of the first part and the entrance to the second part. The entrances to both the first and second parts, being coplanar, present acoustically parallel paths to sound impinging on their common plane. The input impedances of the absorptive surface of the first part and the entrance to the second part are adjusted such that a disproportionately larger share of the incident low frequency acoustical energy passes into the first part and is dissipated. At higher frequencies, an area proportionate share of incident acoustical energy may be absorbed by the first part and the remainder which enters the second part is attenuated by the lined duct portion of the second part.