US3618699A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Multiple pure tone noise suppression device for an aircraft gas turbine engine
Assignee: General Electric Co
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Filing: 1970-04-27
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Granted: 1971-11-09
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Expires: 1990-04-27
Abstract
Abstract Sound suppression means for a gas turbine power plant which includes a fan positioned within a bypass duct surrounding a core engine which drives said fan. An inflatable diaphragm is positioned within an inlet opening of said bypass duct along the inner wall of the casing which surrounds the fan. Means are provided for selectively inflating said diaphragm such that inlet flow along said inner wall can be increased to sonic or near sonic velocity thereby effectively preventing propagation of multiple pure tone noise generated by said fan from said bypass duct.
Inventors
- 👤 Robert C Evans
- 👤 William R Morgan
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-02 21:15
CPC Classifications
B; B64; B64D; B64D33/00; B64D33/02; F; F02; F02C; F02C7/00; F02C7/04; F02C7/042; F02C7/045; B64D2033/0206; B64D2033/0266; B64D2033/0286; Y; Y10; Y10T; Y10T137/00; Y10T137/0536
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
157 words
In a jet propulsion power plant of the turbofan type having a core engine and a fan driven by the core engine, sound suppression means comprising: a cylindrical casing enclosing the fan of said power plant and spaced from said core engine to form therewith an axially extending bypass passageway for the passage of motive fluid between inlet and outlet openings at opposite ends of said casing, expandable means carried by said casing adjacent said inlet opening, said expandable means having a first position wherein it is contiguous with an inner wall of said casing and second position wherein it extends into said bypAss passageway, and means for selectively moving said expandable means between said first and second positions, said second position adapted to increase the velocity of flow near said inner wall to sonic or near sonic velocity whereby multiple pure tone noise generated by said fan is prevented from propagating forwardly through said inlet opening.
Claim 2
Dependent Claim
157 words
In a jet propulsion power plant of the turbofan type having a core engine and a fan driven by the core engine, sound suppression means comprising: a cylindrical casing enclosing the fan of said power plant and spaced from said core engine to form therewith an axially extending bypass passageway for the passage of motive fluid between inlet and outlet openings at opposite ends of said casing, expandable means carried by said casing adjacent said inlet opening, said expandable means having a first position wherein it is contiguous with an inner wall of said casing and second position wherein it extends into said bypAss passageway, and means for selectively moving said expandable means between said first and second positions, said second position adapted to increase the velocity of flow near said inner wall to sonic or near sonic velocity whereby multiple pure tone noise generated by said fan is prevented from propagating forwardly through said inlet opening.
Claim 3
Dependent Claim
49 words
Sound suppression means as recited in claim 1 further characterized in that said expandable means comprises a circumferential elastic diaphragm and means are provided for inflating said diaphragm, said inflating means comprising piping positioned within said casing and lying in fluidic flow cooperation with a source of pressurized fluid.
Claim 4
Dependent Claim
18 words
Sound suppression means as recited in claim 2 wherein said source of pressurized fluid comprises said core engine.
Claim 5
Dependent Claim
35 words
Sound suppression means as recited in claim 3 further characterized in that inflation of said diaphragm affects the velocity of only that portion of the motive fluid flowing near said inner wall of said casing.
Claim 6
Dependent Claim
22 words
Sound suppression means as recited in claim 1 further characterized in that said expandable means comprises a plurality of mechanically actuated panels.
Claim 7
Dependent Claim
24 words
Sound suppression means as recited in claim 5 wherein said panels are covered by a flexible skin which is connected to said inner wall.
References Cited (Backward Citations)
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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) | 1974-11-08 | 1975-05-10 | 1975-11-09 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1978-11-08 | 1979-05-10 | 1979-11-09 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1982-11-08 | 1983-05-10 | 1983-11-09 | $7700.00 | Window Closed / Lapsed |