US4813608A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Bimetallic air seal for exhaust nozzles
Assignee: United States Department of the Air Force
•
Filing: 1986-12-10
•
Granted: 1989-03-21
•
Expires: 2006-12-10
Abstract
Abstract A bimetallic leaf seal 40 for forming an air seal between adjacent structures (38, 42). The bimetallic seal 40 comprises two metallic layers 46, 48 having different coefficients of thermal expansion. The seal moves in a preferred direction upon the application of heat to form an air seal upon the application of heat.
Inventors
- 👤 Joseph Holowach
- 👤 George D. Lee
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 18:10
CPC Classifications
F; F02; F02K; F02K1/00; F02K1/78; F02K1/80; F02K1/805; F16; F16J; F16J15/00; F16J15/02; F16J15/021; F16J15/022; F16J15/024; F16J15/025; F16J15/16; F16J15/164
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
111 words
A leaf seal for use in a high temperature aircraft engine environment, said leaf seal comprising two distinct metallic layers having substantially different coefficients of expansions which cause said leaf seal to bend in a preferred direction upon the application of heat in order to close a gap and form an air seal between adjoining structures wherein at least one of said adjoining structures is movable and wherein said leaf seal is cantilevered from one of said adjoining structures and can withstand temperatures exceeding 1000° F., and further comprises sealing edge stabilizing means that prevents excessive lengthwise warping of the seal due to the differential expansion of the two metallic layers.
Claim 2
Dependent Claim
111 words
A leaf seal for use in a high temperature aircraft engine environment, said leaf seal comprising two distinct metallic layers having substantially different coefficients of expansions which cause said leaf seal to bend in a preferred direction upon the application of heat in order to close a gap and form an air seal between adjoining structures wherein at least one of said adjoining structures is movable and wherein said leaf seal is cantilevered from one of said adjoining structures and can withstand temperatures exceeding 1000° F., and further comprises sealing edge stabilizing means that prevents excessive lengthwise warping of the seal due to the differential expansion of the two metallic layers.
Claim 3
Dependent Claim
15 words
The leaf seal of claim 1 wherein said seal is more than 0.010 inches thick.
Claim 4
Dependent Claim
22 words
The leaf seal of claim 1 wherein the sealing edge stabilizing means comprises a geometric reversal of the two differing metallic layers.
Claim 5
Dependent Claim
90 words
A leaf seal for use in a high temperature aircraft engine environment, said leaf seal comprising two distinct metallic layers having substantially different coefficients of expansion which cause said leaf seal to bend in a preferred direction upon the application of heat in order to form an air seal between adjoining structures wherein said leaf seal withstands temperatures exceeding 1000° F. and comprises periodic slots penetrating only the metallic layer of said leaf seal having the greater coefficients of thermal expansion in order to reduce lengthwise warping of the seal.
Claim 6
Dependent Claim
90 words
A leaf seal for use in a high temperature aircraft engine environment, said leaf seal comprising two distinct metallic layers having substantially different coefficients of expansion which cause said leaf seal to bend in a preferred direction upon the application of heat in order to form an air seal between adjoining structures wherein said leaf seal withstands temperatures exceeding 1000° F. and comprises periodic slots penetrating only the metallic layer of said leaf seal having the greater coefficients of thermal expansion in order to reduce lengthwise warping of the seal.
Claim 7
Dependent Claim
14 words
The leaf seal of claim 1 wherein one of the layers comprises stainless steel.
Claim 8
Dependent Claim
16 words
The leaf seal of claim 1 wherein one of the layers comprises a nickel based alloy.
Claim 9
Dependent Claim
16 words
The leaf seal of claim 5 wherein one of the layers comprises a nickel based alloy.
Claim 10
Dependent Claim
23 words
The leaf seal of claim 1 wherein said seal is utilized to close air gaps between components of a jet engine exhaust nozzle.
Claim 11
Dependent Claim
29 words
The air seal of claim 1 wherein one metallic layer comprises an INCONEL series nickel based alloy and the other metallic layer comprises a high temperature tolerant stainless steel.
Claim 12
Dependent Claim
17 words
The air seal of claim 1 wherein differential air pressure across the seal improves its sealing ability.
References Cited (Backward Citations)
GB722616A
Cited
US2831319A
Cited
US2773709A
Cited
US3354649A
Cited
US3892358A
Cited
US3730436A
Cited
US4022948A
Cited
US4128208A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1992-03-20 | 1992-09-19 | 1993-03-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1996-03-20 | 1996-09-19 | 1997-03-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2000-03-20 | 2000-09-19 | 2001-03-21 | $7700.00 | Window Closed / Lapsed |