US3913626A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Fluid flow ducts
Assignee: Rolls Royce PLC
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Filing: 1973-04-20
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Granted: 1975-10-21
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Expires: 1993-04-20
Abstract
Abstract A fluid flow duct of a gas turbine engine, the duct being defined between a fan cowl and a centrebody and there being provided movable flexible members attached to the centrebody; each member being movable within the duct by fluid pressure between a first concave position and a second convex position for varying the cross-sectional flow area of the duct.
Inventors
- 👤 David Roberts Mcmurtry
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-25 11:47
CPC Classifications
F; F02; F02K; F02K1/00; F02K1/06; F15; F15D; F15D1/00; F15D1/02
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
162 words
A fluid flow duct comprising at least one central wall defining the duct and for which there is provided a plurality of flow area varying means on said central wall therein, said flow area varying means each comprising one flexible sheet material flow area varying member, means for attaching said flow area varying members by their edges to the periphery of respective recesses in the central wall, said members being deployable in operation in either of two positions including a first concave position in which said members are received in the respective recesses and a second convex position, said members being substantially unstretched in either of said two positions, said second convex position being the mirror image of the first concave position and selectively varying the flow area through the duct, the separate fluid pressure means operable on said members for changing the position of said members between said first and second positions wherein fatigue in the unstretched members is substantially reduced.
Claim 2
Dependent Claim
162 words
A fluid flow duct comprising at least one central wall defining the duct and for which there is provided a plurality of flow area varying means on said central wall therein, said flow area varying means each comprising one flexible sheet material flow area varying member, means for attaching said flow area varying members by their edges to the periphery of respective recesses in the central wall, said members being deployable in operation in either of two positions including a first concave position in which said members are received in the respective recesses and a second convex position, said members being substantially unstretched in either of said two positions, said second convex position being the mirror image of the first concave position and selectively varying the flow area through the duct, the separate fluid pressure means operable on said members for changing the position of said members between said first and second positions wherein fatigue in the unstretched members is substantially reduced.
Claim 3
Dependent Claim
32 words
A fluid flow duct according to claim 1 wherein said edges are attached to the respective recesses without sharp bends at said edges to prevent relatively high local stresses at said edges.
Claim 4
Dependent Claim
19 words
A fluid flow duct according to claim 1 in which said member is made from a fibre-reinforced rubber material.
Claim 5
Dependent Claim
17 words
A fluid flow duct according to claim 1 in which said member comprises a sheet metal pressing.
Claim 6
Dependent Claim
30 words
A fluid flow duct according to claim 1 in which the separate means for changing the position of said members comprise means for creating a pressure differential across the members.
Claim 7
Dependent Claim
56 words
A fluid flow duct according to claim 1 further comprising a plurality of flexible sheet material flow area varying members, each said member being attached by their edges to the periphery of a respective recess in the duct wall and wherein said pressure differential creating means includes means for creating the pressure differential across each member.
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) | 1978-10-20 | 1979-04-21 | 1979-10-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-10-20 | 1983-04-21 | 1983-10-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-10-20 | 1987-04-21 | 1987-10-21 | $7700.00 | Window Closed / Lapsed |