Patent US3851994A successfully refreshed from Google Patents.
US3851994A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Blading for axial flow turbo-machine
Assignee: BBC Brown Boveri AG Switzerland
•
Filing: 1973-01-12
•
Granted: 1974-12-03
•
Expires: 1993-01-12
Abstract
Abstract Turbine blading for the rotors of turbo-machines of the axialflow type in which the blades are twisted to allow for a high ratio of external to internal diameter of the flow passageway, the amount of the twist being so selected that it will neither untwist nor increase its twist when subjected to the centrifugal forces which act on the blade when the rotor is operating.
Inventors
- 👤 C Seippel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-01 13:19
CPC Classifications
F; F01; F01D; F01D5/00; F01D5/12; F01D5/14; F01D5/141
Claims Analysis
Total Claims: 3
Claim 1
Independent Claim
180 words
The improvement in turbine blading for the rotor of a turbomachine of the axial-flow type wherein for the purpose of allowing a high ratio of external to internal diameter of the flow passageway each of the blades is given a twist about its horizontal axis which is determined at least approximately in accordance with the equation d Beta /dr T/P . A/I1 + I2 wherein r is the axial pitch of any blade section on which the following values are based. Beta is the angle between the principal inertia axis and the circumferential direction. d Beta /dr is the degree of blade twist T is the resultant torsion moment of the blade part from the distance r to the end of the blade P is the resultant tension force of this part of the blade A is the cross-sectional area of the profile, and I1, I2 are the maximum and minimum moments of inertia of the blade profile thereby maintaining constant the amount of the blade twist under the influence of centrifugal forces acting thereon when the motor is operating.
Claim 2
Dependent Claim
180 words
The improvement in turbine blading for the rotor of a turbomachine of the axial-flow type wherein for the purpose of allowing a high ratio of external to internal diameter of the flow passageway each of the blades is given a twist about its horizontal axis which is determined at least approximately in accordance with the equation d Beta /dr T/P . A/I1 + I2 wherein r is the axial pitch of any blade section on which the following values are based. Beta is the angle between the principal inertia axis and the circumferential direction. d Beta /dr is the degree of blade twist T is the resultant torsion moment of the blade part from the distance r to the end of the blade P is the resultant tension force of this part of the blade A is the cross-sectional area of the profile, and I1, I2 are the maximum and minimum moments of inertia of the blade profile thereby maintaining constant the amount of the blade twist under the influence of centrifugal forces acting thereon when the motor is operating.
Claim 3
Dependent Claim
38 words
Turbine blading as defined in claim 1 wherein all centrifugal force generating vectors along the surface of the blade between its leading and trailing edges extend in a radial direction from the axis of rotation of the rotor.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1977-12-02 | 1978-06-03 | 1978-12-03 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1981-12-02 | 1982-06-03 | 1982-12-03 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1985-12-02 | 1986-06-03 | 1986-12-03 | $7700.00 | Window Closed / Lapsed |