Patent US3779338A successfully refreshed from Google Patents.
US3779338A
Expired / Lapsed
US
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Method of reducing sound generation in fluid flow systems embodying foil structures and the like
Assignee: RTX BBN Technologies Corp
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Filing: 1972-01-27
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Granted: 1973-12-18
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Expires: 1992-01-27
Abstract
Abstract This disclosure deals with preventing or at least reducing sound generation that normally results from fluid flow in various rotor and stator systems about the foil or blade surfaces from the developed fluid forces, by rendering at least portions of the blade of reduced flow impedance, as by rendering the same porous in various degrees.
Inventors
- 👤 R Hayden
- 👤 R Chanaud
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-03 19:39
CPC Classifications
F; F01; F01D; F01D5/00; F01D5/12; F01D5/14; B; B64; B64C; B64C21/00; B64C21/10; F01D5/28; F01D5/282; F04; F04D; F04D29/00; F04D29/26; F04D29/32; F04D29/38; F04D29/388; F04D29/66; F04D29/661; F04D29/668; G; G10; G10K; G10K11/00; G10K11/16; G10K11/161; B64C2230/00; B64C2230/20; B64C2230/22; B64C2230/28; Y; Y02; Y02T; Y02T50/00; Y02T50/10; Y02T50/60
Claims Analysis
Total Claims: 8
Claim 1
Independent Claim
90 words
In a fluid-flow system wherein fluid of a medium flows at substantial pressures about the surfaces of a foil and the like normally giving rise to fluid forces that generate sound, a method of reducing such sound generation, that comprises, reducing the fluid-flow forces interacting with the foil surfaces by reducing the flow impedance of at least one of leading and trailing edge portions of said surfaces to a value substantially closer to the characteristic impedance of the medium, whereby the flow impedance and the characteristic impedance are substantially matched.
Claim 2
Dependent Claim
90 words
In a fluid-flow system wherein fluid of a medium flows at substantial pressures about the surfaces of a foil and the like normally giving rise to fluid forces that generate sound, a method of reducing such sound generation, that comprises, reducing the fluid-flow forces interacting with the foil surfaces by reducing the flow impedance of at least one of leading and trailing edge portions of said surfaces to a value substantially closer to the characteristic impedance of the medium, whereby the flow impedance and the characteristic impedance are substantially matched.
Claim 3
Dependent Claim
19 words
A method as claimed in claim 1 and in which said reducing is effected by rendering said surfaces porous.
Claim 4
Dependent Claim
22 words
A method as claimed in claim 2 and in which the degree of porosity is varied for different portions of said foil.
Claim 5
Dependent Claim
20 words
A method as claimed in claim 1 and in which at least one portion of said foil is maintained solid.
Claim 6
Dependent Claim
19 words
A method as claimed in claim 1 and in which an intermediate portion of said foil is maintained impervious.
Claim 7
Dependent Claim
34 words
A method as claimed in claim 1 and in which the ratio of the reduced flow impedance to the characteristic impedance of the medium is within the range of substantially 1 to substantially 10.
Claim 8
Dependent Claim
27 words
A method as claimed in claim 1 and in which the reducing of the flow impedance comprises providing a comb-like structure protruding from said trailing edge portion.
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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) | 1976-12-17 | 1977-06-18 | 1977-12-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-12-17 | 1981-06-18 | 1981-12-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-12-17 | 1985-06-18 | 1985-12-18 | $7700.00 | Window Closed / Lapsed |