US3692141A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of and means for noise attenuation
Assignee: Dassault Aviation SA
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Filing: 1971-10-28
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Granted: 1972-09-19
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Expires: 1991-10-28
Abstract
Abstract The noise originating from acoustic energy transmitted through a duct is suppressed by focusing it, by means of properly designed acoustic reflectors, so that it is concentrated on localized restricted zones of the duct wall, the provision of adequate sound absorptive linings being limited to these restricted zones. This noise suppressing system is applicable to air intakes of turbojets, turbofan casings, silencers for the jet of jet propulsion units.
Inventors
- 👤 Andre Julien Labussiere
- 👤 Joseph Henri Leon
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 20:15
CPC Classifications
F; F04; F04D; F04D29/00; F04D29/66; F04D29/661; F04D29/668; F02; F02C; F02C7/00; F02C7/04; F02C7/045; F02K; F02K1/00; F02K1/78; F02K1/82; F02K1/827; F02P; F02P7/00; F02P7/06; F02P7/063; F02P7/0632; F04D29/663; F04D29/664; Y; Y10; Y10T; Y10T137/00; Y10T137/0536
Claims Analysis
Total Claims: 11
Claim 1
Independent Claim
69 words
Method for suppressing noise caused by acoustic energy propagated from a source, comprising the steps of tunneling said acoustic energy over a major length between two spaced substantially coaxial cross-sectional areas respectively adjacent to and remote from said source, reflecting said acoustic energy to focus it on a confined minor fraction of said major length intermediate said cross-sections, and providing acoustic energy absorbent material exclusively on said minor fraction.
Claim 2
Dependent Claim
69 words
Method for suppressing noise caused by acoustic energy propagated from a source, comprising the steps of tunneling said acoustic energy over a major length between two spaced substantially coaxial cross-sectional areas respectively adjacent to and remote from said source, reflecting said acoustic energy to focus it on a confined minor fraction of said major length intermediate said cross-sections, and providing acoustic energy absorbent material exclusively on said minor fraction.
Claim 3
Independent Claim
95 words
A method of suppressing noise caused by acoustical energy accompanying a high speed flow of gaseous fluid which comprises passing said flow of fluid through an annular flow path between generally coaxial inlet and outlet openings spaced apart a substantial distance; without substantially interfering with the smooth flow of said fluid through said flow path, reflecting said acoustic energy to focus it on a limited fraction of said flow path; and providing acoustical energy absorbent material exclusively on the limited fraction of said flow path while leaving the remainder thereof free of said absorbent material.
Claim 4
Independent Claim
95 words
A method of suppressing noise caused by acoustical energy accompanying a high speed flow of gaseous fluid which comprises passing said flow of fluid through an annular flow path between generally coaxial inlet and outlet openings spaced apart a substantial distance; without substantially interfering with the smooth flow of said fluid through said flow path, reflecting said acoustic energy to focus it on a limited fraction of said flow path; and providing acoustical energy absorbent material exclusively on the limited fraction of said flow path while leaving the remainder thereof free of said absorbent material.
Claim 5
Dependent Claim
59 words
The method of claim 2 wherein said annular flow path is contained between two radially spaced apart elongated surfaces of revolution, one of which includes a portion of gradually increasing radius, and said acoustical energy absorbing material is provided on a portion of the other of said surfaces generally opposite the portion of increasing radius of said first surface.
Claim 6
Dependent Claim
88 words
System for suppressing noise caused by acoustic energy propagated from a source, comprising a duct bounded by a wall extending over a major length between two spaced substantially coaxial openings respectively adjacent to and remote from said source and defining between said openings a flow path of generally rectilinear axis, acoustic energy absorbing means confined to a minor length of said wall intermediate said openings, and an acoustic energy focusing reflector positioned opposite said minor wall length and designed for concentrating acoustic energy on said confined absorbing means.
Claim 7
Dependent Claim
88 words
System for suppressing noise caused by acoustic energy propagated from a source, comprising a duct bounded by a wall extending over a major length between two spaced substantially coaxial openings respectively adjacent to and remote from said source and defining between said openings a flow path of generally rectilinear axis, acoustic energy absorbing means confined to a minor length of said wall intermediate said openings, and an acoustic energy focusing reflector positioned opposite said minor wall length and designed for concentrating acoustic energy on said confined absorbing means.
Claim 8
Dependent Claim
54 words
Noise suppressing system as claimed in claim 4 wherein said duct is bounded by radially-spaced inner and outer walls defining therebetween an annular flow path of generally rectilinear axis, and wherein said acoustic energy focusing reflector is positioned on said inner wall and said acoustic energy absorbing means is confined on said outer wall.
Claim 9
Dependent Claim
25 words
Noise suppressing system as claimed in claim 5 wherein said duct is in the general shape of a solid of revolution about said rectilinear axis.
Claim 10
Dependent Claim
25 words
Noise suppressing system as in claim 4 wherein said energy focusing reflector is defined by a portion of said inner wall of gradually increasing radius.
Claim 11
Dependent Claim
33 words
The system of claim 7 wherein the maximum radius of said reflector portion of said inner wall is substantially equal to the minimum radius of said outer wall at a remote point thereon.
References Cited (Backward Citations)
No citation records indexed.
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1975-09-19 | 1976-03-20 | 1976-09-19 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1979-09-19 | 1980-03-20 | 1980-09-19 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1983-09-19 | 1984-03-20 | 1984-09-19 | $7700.00 | Window Closed / Lapsed |