US3834833A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Blade construction for axial-flow turbo-machines and method of protecting turbo-machine blades against stress corrosion cracking
Assignee: BBC Brown Boveri AG Switzerland
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Filing: 1973-02-16
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Granted: 1974-09-10
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Expires: 1993-02-16
Abstract
Abstract A steel blade for an axial-flow turbo-machine is disclosed which has a hardened leading edge portion. In accordance with the invention, the hardened edge portion is imparted with a permanent compressive prestress in the direction of the longitudinal axis of the blade. This protects the blade against stress corrosion cracking.
Inventors
- 👤 G Faber
- 👤 C Maggi
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 17:21
CPC Classifications
F; F01; F01D; F01D5/00; F01D5/12; F01D5/28; F01D5/286; C; C21; C21D; C21D9/00; C21D9/0068
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
48 words
In a steel blade of an axial-flow turbo-machine, wherein the blade has a hardened edge portion, the improvement which comprises that said edge portion exhibits a permanent compressive prestress in the direction of the longitudinal axis of the blade, whereby said blade is protected against stress corrosion cracking.
Claim 2
Dependent Claim
48 words
In a steel blade of an axial-flow turbo-machine, wherein the blade has a hardened edge portion, the improvement which comprises that said edge portion exhibits a permanent compressive prestress in the direction of the longitudinal axis of the blade, whereby said blade is protected against stress corrosion cracking.
Claim 3
Dependent Claim
29 words
The improvement of claim 1, wherein the cross-sectional area of said hardened edge portion amounts to at the most twenty percent of the total cross-sectiOnal area of the blade.
References Cited (Backward Citations)
GB195050A
Cited
US2888244A
Cited
US3148954A
Cited
US3371908A
Cited
US3564689A
Cited
US3729345A
Cited
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-09-09 | 1978-03-11 | 1978-09-10 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-09-09 | 1982-03-11 | 1982-09-10 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-09-09 | 1986-03-11 | 1986-09-10 | $7700.00 | Window Closed / Lapsed |