US3867061A
Expired / Lapsed
US
⏱️ 0.0 years remaining
Shroud structure for turbine rotor blades and the like
Assignee: Curtiss Wright Corp
•
Filing: 1973-12-26
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Granted: 1975-02-18
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Expires: 1993-12-26
Abstract
Abstract An improved honeycomb shroud for rotor blades for turbines and similar devices, wherein the rub-tolerance of the shroud is increased by making the honeycomb less rigid and more resilient and yieldable at the potential rubbing surface, with added strength at the region of attachment to the support member.
Inventors
- 👤 Seymour Moskowitz
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-11-09 01:31
CPC Classifications
F; F01; F01D; F01D11/00; F01D11/08; F01D11/12; F01D11/127; Y; Y02; Y02T; Y02T50/00; Y02T50/60
Claims Analysis
Total Claims: 7
Claim 1
Independent Claim
188 words
In a fluid flow device having a rotor with generally radially extending blades coacting with fluid flowing betweeN the blades, a shroud structure circumferentially surrounding the tips of the rotor blades in close proximity thereto to minimize leakage of fluid across the blade tips, the gap between the blade tips and the apposed surface of the shroud structure having in the cold state of the device a radial dimension which may diminish during operation sufficiently to cause rubbing contact between the blade tips and the shroud, the improvement comprising: a. the shroud having a plurality of strips convoluted in a semihexagonal configuration in their longitudinal direction, each of the strips having one edge affixed to a rigid backing element and its opposite edge freestanding in the radial direction and apposed to the blade tips, b. the strips being disposed with their convoluted length approximately parallel to the chordal centerline of the rotating blade tips, c. the freestanding edges of the strips being resilient to rubbing contact with the blade tips in the generally circumferential direction of the shroud and generally transversely to the convoluted longitude of the strips.
Claim 2
Dependent Claim
188 words
In a fluid flow device having a rotor with generally radially extending blades coacting with fluid flowing betweeN the blades, a shroud structure circumferentially surrounding the tips of the rotor blades in close proximity thereto to minimize leakage of fluid across the blade tips, the gap between the blade tips and the apposed surface of the shroud structure having in the cold state of the device a radial dimension which may diminish during operation sufficiently to cause rubbing contact between the blade tips and the shroud, the improvement comprising: a. the shroud having a plurality of strips convoluted in a semihexagonal configuration in their longitudinal direction, each of the strips having one edge affixed to a rigid backing element and its opposite edge freestanding in the radial direction and apposed to the blade tips, b. the strips being disposed with their convoluted length approximately parallel to the chordal centerline of the rotating blade tips, c. the freestanding edges of the strips being resilient to rubbing contact with the blade tips in the generally circumferential direction of the shroud and generally transversely to the convoluted longitude of the strips.
Claim 3
Dependent Claim
76 words
The combination recited in claim 1, wherein a second plurality of semihexagonally convoluted strips are affixed to the backing element in alternating relationship with the first plurality of strips, the second strips having their convolutions opposed to the convolutions of the first strips to form hexagonal cells therewith, the second strips having less radial height than the first strips so that the hexagonal cells have less radial height than the freestanding edges of the first strips.
Claim 4
Dependent Claim
61 words
The combination recited in claim 2, wherein the over-all direction of fluid flow through the device is in a direction generally parallel to the axis of rotor rotation, and the first strips are disposed at such an angle to the axis that there is no clear line of sight in the axial direction between the freestanding edges of the first strips.
Claim 5
Dependent Claim
41 words
The combination recited in claim 3, wherein fluid enters the passages between rotor blades at an angle to the axis, and the freestanding strips are disposed with their longitude at an angle to the direction of fluid entering the blade passages.
Claim 6
Dependent Claim
36 words
The combination recited in claim 2, wherein the hexagonal cells and the spaces between the freestanding edges of the first strips are filled with a yieldable filler material to approximately the height of the freestanding edges.
Claim 7
Dependent Claim
16 words
The combination recited in claim 5, wherein the yieldable filler material is a compressible metallic sponge.
References Cited (Backward Citations)
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US3068016A
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US3053694A
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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) | 1978-02-17 | 1978-08-19 | 1979-02-18 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1982-02-17 | 1982-08-19 | 1983-02-18 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 1986-02-17 | 1986-08-19 | 1987-02-18 | $7700.00 | Window Closed / Lapsed |