US3745629A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Method of determining optimal shapes for stator blades
Assignee: SECR DEFENCE
•
Filing: 1972-04-12
•
Granted: 1973-07-17
•
Expires: 1992-04-12
Abstract
Abstract In an effort to prevent vibration-induced cracking of stator blades of the type that are secured at their radially inner and outer ends a complete stator assembly is made up and its vibration characteristics are investigated. The normal blades are then replaced by blades which are curved to the shape assumed by the normal blades in the predominant mode of vibration found by the investigation. This technique has been found to reduce vibration substantially.
Inventors
- 👤 G Pask
- 👤 N Robinson
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-31 05:12
CPC Classifications
F; F01; F01D; F01D9/00; F01D9/02; F01D9/04; F01D9/041; F01D5/00; F01D5/12; F01D5/14; F01D5/16; Y; Y10; Y10T; Y10T29/00; Y10T29/49; Y10T29/49316; Y10T29/4932; Y10T29/49323; Y10T29/49758
Claims Analysis
Total Claims: 5
Claim 1
Independent Claim
146 words
A method of manufacturing an assembly of stator blades having means securing each blade at its radially inner and outer portion, said method comprising the following steps: a. producing an annular array of stator blades, each blade having an intermediate portion which is substantially straight in a radial sense, b. subjecting said array of stator blades to operating conditions substantially identical to the desired operating conditions of said stator blades, c. determining the predominate mode of vibration of each of said stator blades under said operating conditions, and d. replacing each of said stator blades with a stator blade having an intermediate portion which is curved to a shape similar to the shape assumed by each of said straight stator blades while vibrating in its predominate mode of vibration, but which is otherwise substantially identical to said intermediate portion of a corresponding said straight stator blade.
Claim 2
Independent Claim
146 words
A method of manufacturing an assembly of stator blades having means securing each blade at its radially inner and outer portion, said method comprising the following steps: a. producing an annular array of stator blades, each blade having an intermediate portion which is substantially straight in a radial sense, b. subjecting said array of stator blades to operating conditions substantially identical to the desired operating conditions of said stator blades, c. determining the predominate mode of vibration of each of said stator blades under said operating conditions, and d. replacing each of said stator blades with a stator blade having an intermediate portion which is curved to a shape similar to the shape assumed by each of said straight stator blades while vibrating in its predominate mode of vibration, but which is otherwise substantially identical to said intermediate portion of a corresponding said straight stator blade.
Claim 3
Dependent Claim
61 words
A method as claimed in claim 1 including the step of replacing each of the straight stator blades with a stator blade having an intermediate portIon which is curved to a shape similar to the shape which would be assumed by a straight, but otherwise substantially identical blade in use when its predominate mode of vibration is its first flap mode.
Claim 4
Dependent Claim
61 words
A method as claimed in claim 1 including the step of replacing each of the straight stator blades with a stator blade having an intermediate portion which is curved to a shape similar to the shape which would be assumed by a straight, but otherwise substantially identical blade in use when its predominate mode of vibration is is second flap mode.
Claim 5
Dependent Claim
61 words
A method as claimed in claim 1 including the step of replacing each of the straight stator blades with a stator blade having an intermediate portion which is curved to a shape similar to the shape which would be assumed by a straight, but otherwise substantially identical blade in use when its predominate mode of vibration is its third flap mode.
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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) | 1976-07-16 | 1977-01-15 | 1977-07-17 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1980-07-16 | 1981-01-15 | 1981-07-17 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1984-07-16 | 1985-01-15 | 1985-07-17 | $7700.00 | Window Closed / Lapsed |