Claims
- 1. A multistage turbine comprising:
- (a) a rotor disk having a cylindrical outer surface in which a plurality of dovetail-shaped grooves are formed;
- (b) a casing surrounding said rotor disk;
- (c) a plurality of dovetail-shaped anchoring portions, each one of said plurality of dovetail-shaped anchoring portions being slidably received in a corresponding one of said plurality of dovetail-shaped grooves;
- (d) a first turbine stage comprising a plurality of axially aligned, circumferentially equally spaced first turbine blades, at least one of said first turbine blades being mounted on each one of said plurality of dovetail-shaped anchoring portions and projecting radially outwardly from said rotor disk;
- (e) a second turbine stage located downstream of said first turbine stage and comprising a plurality of axially aligned, circumferentially equally spaced second turbine blades, at least one of said second turbine blades being mounted on each one of said plurality of dovetail-shaped anchoring portions and projecting radially outwardly from said rotor disk;
- (f) a plurality of axially aligned, circumferentially equally spaced first nozzle plates mounted on said casing and projecting inwardly therefrom, said first nozzle plates being located upstream of and closely adjacent to said first turbine stage;
- (g) a plurality of axially aligned, circumferentially equally spaced second nozzle plates mounted on said casing and projecting radially inwardly therefrom, said second nozzle plates being located between said first and second turbine stages and closely adjacent to said second turbine stage;
- (h) a first circumferentially extending shroud surrounding said first turbine stage and connecting the radially outer ends of at least some of said first turbine blades, said first circumferentially extending shroud being divided by gaps at intervals in the circumferential direction; and
- (i) a second circumferentially extending shroud surrounding said second turbine stage and connecting the radially outer ends of at least some of said second turbine blades, said second circumferentially extending shroud being divided by gaps at intervals in the circumferential direction and the gaps dividing portions of said second circumferentially extending shroud being offset in the circumferential direction from the gaps dividing portions of said first circumferentially extending shroud,
- whereby, in use, the vibration level of said first and second turbine blades due to the eddies-containing wakeflow coming from the trailing edges of said first and second nozzle plates is greatly reduced.
- 2. A multistage turbine as recited in claim 1 wherein said plurality of dovetail-shaped grooves extend circumferentially in the cylindrical outer surface of said rotor disk.
- 3. A multistage turbine as recited in claim 1 wherein said plurality of dovetail-shaped grooves extend axially in the cylindrical outer surface of said rotor disk.
- 4. A multistage turbine as recited in claim 1 wherein the number of turbine blades in said first and second turbine stages is equal.
- 5. A multistage turbine as recited in claim 1 wherein the ratio of the number of turbine blades in said first turbine stage to the number of turbine blades in said second turbine stage is an integer.
- 6. A multistage turbine as recited in claim 1 wherein:
- (a) the number of first nozzle plates is equal to the number of second nozzle plates and
- (b) the position of said first nozzle plates is offset in the circumferential direction by half the pitch between said second nozzle plates.
- 7. A multistage turbine as recited in claim 1 wherein said second nozzle plates are located closely adjacent to both of said turbine stages.
Priority Claims (1)
Number |
Date |
Country |
Kind |
59-253265 |
Nov 1984 |
JPX |
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Parent Case Info
This application is a continuation of application Ser. No. 803,348, filed on Dec. 2, 1985, now abandoned.
US Referenced Citations (7)
Foreign Referenced Citations (3)
Number |
Date |
Country |
53-92008 |
Jan 1978 |
JPX |
53-126409 |
Apr 1978 |
JPX |
6745 |
Jan 1904 |
GBX |
Non-Patent Literature Citations (1)
Entry |
Table I. Stator Blade Coordinates NASA, pp. 13-18. |
Continuations (1)
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Number |
Date |
Country |
Parent |
803348 |
Dec 1985 |
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