US3574477A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Noise attenuating system for rotary engines
Assignee: Boeing Co
•
Filing: 1969-02-19
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Granted: 1971-04-13
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Expires: 1989-02-19
Abstract
Abstract A plurality of angularly arranged baffles or blades which are radially mounted to form a fan type construction. The fan is mounted for free rotation in the fluid stream of a rotary engine in the path of the propagating sound waves emitted from the engine. During operation the rotating fan will present a barrier to the sound waves and cause them to be either reflected or scattered towards an area having sound absorbing characteristics while offering a minimum obstruction to the fluid flow. A further sound attenuation and an improvement in engine performance is achieved through a predetermined air pressure profile which is obtained by fairing the blade angle configuration, whereby the inlet air drives the outer portion of the rotating blades and the inner portion of the blades compresses the inlet air. Any engine performance loss which is experienced by the fan type apparatus is offset by the improved air pressure profile at the first stage engine inlet area.
Inventors
- 👤 Hans R Dolf
- 👤 John D Mcalister
- 👤 Edwin J Zapel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-23 18:01
CPC Classifications
F; F02; F02C; F02C7/00; F02C7/04; F02C7/045; F02K; F02K1/00; F02K3/00; F02K3/02; F02K3/04; F02K3/065; F04; F04D; F04D29/00; F04D29/66; F04D29/661; F04D29/663; Y; Y02; Y02T; Y02T50/00; Y02T50/60
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
47 words
A noise attenuating apparatus for roTating engines comprising: a. a plurality of angularly arranged and radially positioned blades: b. said blades mounted for free rotation about said engine axis of rotation in said engine fluid inlet and exit passageways in front and aft of said engine, respectively.
Claim 2
Dependent Claim
47 words
A noise attenuating apparatus for roTating engines comprising: a. a plurality of angularly arranged and radially positioned blades: b. said blades mounted for free rotation about said engine axis of rotation in said engine fluid inlet and exit passageways in front and aft of said engine, respectively.
Claim 3
Dependent Claim
22 words
A noise attenuating apparatus for rotating engines as claimed in claim 1 wherein said plurality of blades form a fan assembly structure.
Claim 4
Dependent Claim
37 words
A noise attenuating apparatus for rotating engines as claimed in claim 2 wherein said rotating engine comprises a bypass turbine engine with an inlet duct and wherein said fan assembly structure is mounted for free rotation therein.
Claim 5
Dependent Claim
39 words
A noise attenuating apparatus as claimed in claim 3 wherein said plurality of angularly arranged and radially mounted blades in said fan assembly structure comprises blades having each a twisted configuration for regulating said inlet air towards said engine.
Claim 6
Dependent Claim
108 words
A noise attenuating apparatus as claimed in claim 4 wherein each said twisted blade comprises a tip and a root, and from said tip to said root, an outer portion, a middle portion and an inner portion. 6 A noise attenuating apparatus as claimed in claim 5 wherein said twisted blade configuration for each said blade from said tip to said root comprises a blade surface wherein said outer portion is provided with a convex contour which gradually decreases to a flat surface at said middle portion and which surface gradually increases to a concave contour from said middle portion via via said inner portion towards said root.
Claim 7
Dependent Claim
138 words
A noise attenuating apparatus as claimed in claim 6 wherein said fan assembly structure upon rotation covers a circular shielding area wherein an outer concentric ring of said circular area corresponds to said blades outer portion positioned parallel to said bypass fan duct exit opening and wherein an inner concentric ring of said circular area corresponds to said blades inner portion and is positioned parallel to said engine first stage inlet area. 8 A noise attenuating apparatus as claimed in claim 7 wherein said blade configuration upon rotation of said fan assembly structure is adapted to be driven by said inlet air at said outer portions and wherein said inlet air will be compressed at said inner portions of said fan assembly structure so that a predetermined air pressure column is produced by said free rotating fan structure.
Claim 8
Dependent Claim
36 words
A noise attenuating apparatus as claimed in claim 8 wherein said inlet duct of said turbine bypass engine and said blades of said free rotating fan structure are covered by a material having sound absorbing characteristics.
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USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1974-04-12 | 1974-10-12 | 1975-04-13 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-04-12 | 1978-10-12 | 1979-04-13 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-04-12 | 1982-10-12 | 1983-04-13 | $7700.00 | Window Closed / Lapsed |