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US3953148A Expired / Lapsed US ⏱️ 0.0 years remaining

Configuration of the last moving blade row of a multi-stage turbine

Assignee: BBC Brown Boveri AG Switzerland
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Filing: 1974-04-26
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Granted: 1976-04-27
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Expires: 1994-04-26
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Abstract

Abstract A multi-stage axial-flow turbine structure where in order to reduce the energy content of the gaseous working medium leaving the last moving blade row in comparison to the available heat drop, the flow discharge cross-section area from the last moving row, compared to the flow discharge cross-section area of the penultimate moving row, is made larger by some 10 to 40 % than would correspond to the ratio of the increase in volume of the working medium from the penultimate to the last moving blade now. This is accomplished, for example, by increasing the ratio of the passage width to blade pitch and/or by increasing the annular flow area, this ratio being varied over the length of the blades of the last row in order to obtain a uniform velocity profile in the axial and tangential directions. The desired result can also be obtained by making the flow discharge cross-section area of all moving blade rows preceding the last row smaller by an amount corresponding to the reduction in heat drop of the last moving blade row brought about by enlarging its cross-section area such as by decreasing the ratio of passage width to blade pitch and/or by reducing the annular flow area.

Inventors

  • 👤 Claude Seippel
  • 👤 Arnulf Teufelberger

Bibliographic Details

Application Number —
Jurisdiction US
Data Source google_patents
Last Synchronized 2026-11-08 09:09
CPC Classifications
F; F01; F01D; F01D1/00; F01D1/02; F01D1/04; Y; Y10; Y10S; Y10S416/00; Y10S416/02

Claims Analysis

Total Claims: 8
Claim 1
Independent Claim 92 words
In a turbine of axial construction through which an expanding gaseous working medium flows and which has more than two stages, each stage comprising one fixed blade row and one moving blade row, the improvement wherein the flow discharge cross-section area from only the last moving blade row is larger than the flow discharge cross-section of the penultimate moving blade row by an amount which is from 10 to 40% larger than the ratio of the increase in volume of the flow medium from the penultimate to the last moving blade row.
Claim 2
Dependent Claim 92 words
In a turbine of axial construction through which an expanding gaseous working medium flows and which has more than two stages, each stage comprising one fixed blade row and one moving blade row, the improvement wherein the flow discharge cross-section area from only the last moving blade row is larger than the flow discharge cross-section of the penultimate moving blade row by an amount which is from 10 to 40% larger than the ratio of the increase in volume of the flow medium from the penultimate to the last moving blade row.
Claim 3
Dependent Claim 33 words
A turbine as claimed in claim 1, in which the flow discharge cross-section area of the last moving row is enlarged by increasing the ratio of passage width (q) to blade pitch (t).
Claim 4
Dependent Claim 45 words
A turbine as claimed in claim 2, in which the ratio of passage width (q) to blade pitch (t) varies over the length of the blades (8) of the last row in order to obtain a uniform velocity profile in the axial and tangential directions.
Claim 5
Dependent Claim 55 words
A turbine as claimed in claim 1, in which, in order to maintain a predetermined heat drop, the flow discharge cross-section area of all blade rows preceding the last row is made smaller by an amount corresponding to the reduction in heat drop of the last moving row brought about by enlarging its cross-section area.
Claim 6
Dependent Claim 35 words
A turbine as claimed in claim 4, in which the flow discharge cross-section of all rows preceding the last row is made smaller by decreasing the ratio of passage width (q) to blade pitch (t).
Claim 7
Dependent Claim 27 words
A turbine as claimed in claim 1, in which the flow discharge cross-section area of the last moving row is enlarged by increasing the annular flow area.
Claim 8
Dependent Claim 40 words
A turbine as claimed in claim 1, in which the flow discharge cross-section area of the last moving row is enlarged by increasing the ratio of passage width (q) to blade pitch (t) and by increasing the annular flow area.

References Cited (Backward Citations)

US925065A Cited
US1390733A Cited
US1475213A Cited
US1526814A Cited
US1771023A Cited
US2224519A Cited
US2258792A Cited

USPTO Annuity & Maintenance Windows

Annuity Stage Window Opens Payment Deadline Surcharge Period Until Estimated Fee Status
3.5 Years (Year 4) 1979-04-27 1979-10-27 1980-04-27 $2000.00 Window Closed / Lapsed
7.5 Years (Year 8) 1983-04-27 1983-10-27 1984-04-27 $3760.00 Window Closed / Lapsed
11.5 Years (Year 12) 1987-04-27 1987-10-27 1988-04-27 $7700.00 Window Closed / Lapsed

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