US4466772A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Circumferentially grooved shroud liner
Assignee: Pratt and Whitney Canada Corp
•
Filing: 1981-01-27
•
Granted: 1984-08-21
•
Expires: 2001-01-27
Abstract
Abstract A turbine is provided with a stationary shroud surrounding a rotor provided with a plurality of radially extending blades. The stationary shroud includes a plurality of spaced-apart lands defining therebetween openings to deflect the flow leakage from the high pressure side of each blade to the low pressure side of the respective blade.
Inventors
- 👤 Ulo Okapuu
- 👤 Kiritkumar V. Patel
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-07 23:42
CPC Classifications
F; F01; F01D; F01D11/00; F01D11/08; Y; Y02; Y02T; Y02T50/00; Y02T50/60
Claims Analysis
Total Claims: 12
Claim 1
Independent Claim
162 words
A gas turbine engine having a rotor provided with a plurality of radially extending blades and a stationary shroud surrounding the rotor, each blade having a high pressure side and a low pressure side relative to the fluid flow and a substantially smooth tip end surface, the stationary shroud comprising in its radially inward facing surface, a plurality of spaced-apart lands providing parallel grooves in the surface formed so as to reduce leakage of working fluid from the high pressure side to the lower pressure side of the rotor, said parallel grooves being inclined relative to a radial plane towards the fluid flow at an angle between 10° and 40°, the thickness of each land, the spacing between the lands and the depth of the groove being selected as a function of the flow characteristics of the turbine, and wherein t/d>1 where t is the width dimension of the widest part of the blade and d is the depth of the grooves.
Claim 2
Dependent Claim
162 words
A gas turbine engine having a rotor provided with a plurality of radially extending blades and a stationary shroud surrounding the rotor, each blade having a high pressure side and a low pressure side relative to the fluid flow and a substantially smooth tip end surface, the stationary shroud comprising in its radially inward facing surface, a plurality of spaced-apart lands providing parallel grooves in the surface formed so as to reduce leakage of working fluid from the high pressure side to the lower pressure side of the rotor, said parallel grooves being inclined relative to a radial plane towards the fluid flow at an angle between 10° and 40°, the thickness of each land, the spacing between the lands and the depth of the groove being selected as a function of the flow characteristics of the turbine, and wherein t/d>1 where t is the width dimension of the widest part of the blade and d is the depth of the grooves.
Claim 3
Dependent Claim
18 words
A turbine engine as claimed in claim 1, wherein the angle of inclination is between 20° and 30°.
Claim 4
Dependent Claim
25 words
An apparatus as defined in claim 1, wherein the stationary shroud surrounds a turbine rotor and the shroud includes a plurality of circumferentially extending grooves.
Claim 5
Dependent Claim
24 words
An apparatus as defined in claim 1, wherein the grooves in the shroud have a depth equal to the chord length of the blade.
Claim 6
Dependent Claim
26 words
An apparatus as defined in claim 1, wherein the grooves in the shroud have a depth covering a fraction of the chord length of the blade.
Claim 7
Dependent Claim
29 words
An apparatus as defined in claim 1, wherein the lands define grooves extending parallel and at an angle to the axis of the rotor which is other than 90°.
Claim 8
Dependent Claim
24 words
A turbine engine as claimed in claim 2, wherein the grooves have a depth from 0.050 inch (1.27 mm) to 0.150 inch (3.81 mm).
Claim 9
Dependent Claim
27 words
A turbine engine as claimed in claim 2 or claim 3, wherein there are not less than four grooves distributed over the chord length of the tip.
Claim 10
Dependent Claim
21 words
An apparatus as defined in claim 7, wherein the grooves extend over the area of the leading edge of the blade.
Claim 11
Dependent Claim
18 words
An apparatus as defined in claim 7, wherein the grooves extend over the trailing edge of the blade.
Claim 12
Dependent Claim
22 words
An apparatus as defined in claim 10, wherein the angle of the grooves is defined by 90° less the inlet flow angle.
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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) | 1987-08-21 | 1988-02-20 | 1988-08-21 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1991-08-21 | 1992-02-20 | 1992-08-21 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1995-08-21 | 1996-02-20 | 1996-08-21 | $7700.00 | Window Closed / Lapsed |