The invention relates generally to gas turbine engine and, more particularly, to a new gas turbine engine shroud sealing arrangement.
Over the years various sealing arrangements have been designed to seal the annular shrouds surrounding the tips of turbine blades. Feather seals are typically installed in the aft and forward rails of the shroud support structures to minimize cooling air leakage through the shroud segments.
A main disadvantage of such feather seals is that it provides for a multi-part sealing arrangement (e.g. 12–24 feather seals) which renders the assembly procedure more complex, thereby resulting in extra costs. Furthermore, feather slots must be machined in each shroud segments for allowing the feather seals to be positioned in the aft and forward rails of the outer shroud support, which further increases the manufacturing cost of the engine. Finally, such a multi-part sealing arrangement contributes to increase the overall weight of the gas turbine engine.
It is therefore an object of this invention to provide a new sealing arrangement which addresses the above mentioned concerns.
In one aspect, the present invention provides a turbine blade tip shroud assembly comprising an annular shroud support having at least one radially inner annular flange defining a groove, a shroud supportively engaged in said groove, said shroud having a platform, the platform having a hot gas path side and a back side, an annular gap being defined radially inwardly of said groove between said back side of said platform and a radially inwardly facing side of said at least one annular flange, and a ring seal having a spring-loaded annular sealing portion and a radial flange extending from one end of said spring-loaded annular sealing portion, the spring-loaded annular sealing portion extending axially in said annular gap in sealing engagement with said back side and said radially inwardly facing surface of said at least one annular flange, and wherein the radial flange is in axial abutment relationship with an axially facing surface of one of said shroud and said at least one annular flange of said shroud support.
In another aspect, the present invention provides a ring seal in combination with a turbine shroud adapted to surround a stage of turbine blades, the turbine shroud comprising a support ring and a shroud mounted within said support ring, the shroud comprising a platform having an aft overhanging portion, said aft overhanging portion having a gas path side and a back side opposite said gas path side, said back side defining with an opposed facing radially inner surface of said support ring an annular gap, said ring seal being mounted in said annular gap and maintained in sealing engagement with said radially inner surface of said support ring and said back side of said aft overhanging portion of said platform.
In another aspect, the present invention provides a method for sealing a turbine shroud comprising a platform overhanging portion having a gas path side and an opposed back side, the back side being spaced-radially inwardly from a radially inner surface of a surrounding support ring, the method comprising the step of mounting an annular seal in sealing engagement with said the back side of the platform overhanging portion and the radially inner surface of the surrounding support ring.
Further details of these and other aspects of the present invention will be apparent from the detailed description and figures included below.
Reference is now made to the accompanying figures depicting aspects of the present invention, in which:
The turbine section 18 comprises, among others, a turbine rotor mounted for rotation about a centerline axis of the engine 10. The turbine rotor comprises a plurality of circumferentially spaced-apart blades 22 (only one shown in
Each shroud segment 28 comprises a platform 30 and a pair of retention hooks 32 and 34 extending radially outwardly from a back side 36 (i.e. the radially outwardly facing side) of the platform 30 opposite to a gas path side 38 thereof (i.e. the radially inwardly facing side). The platform 30 has an aft overhanging portion 40 extending axially rearward of the aft retention hook 34. The forward and aft retention hooks 32 and 34 are respectively provided with axially aft extending terminal components 32a and 34a conventionally axially engaged in respective forwardly facing annular grooves 42 and 44 defined by a pair of forward and aft annular flanges 46 and 48 extending integrally radially inwardly from a radially inner surface 50 of a surrounding annular shroud support 52.
Holes 54 are defined in the shroud support 52 to allow cooling air to flow into the annular cavity 56 formed between the shroud 26 and the support structure 52. As shown in
The wave-shaped component 60 has first, second and third peaks 64, 66 and 68. The configuration of wave-shaped component 60 is such that the radial extent between top peak 66 and bottom peaks 64 and 68 is slightly greater than the radial dimension between the radially inwardly facing surface 70 of the aft flange 48 of the shroud support 52 and the back side 36 of the overhanging portion 40 of the shroud platform 30. The seal 58 is made up of a heat resistant material having an inherent resiliency suitable to maintain spring fitted continual contact with the opposed facing surfaces 36 and 70 of the gap 59. Thus, the wave-shaped component 60 is spring loaded between the aft overhanging portion 40 of the shroud platform 30 and the aft flange 48 of the shroud support 52 so that peaks 64, 66 and 68 are in continual contact with the opposed facing surfaces 36 and 70 of the annular gap 59. In addition to prevent cooling air leakage through the annular gap 59, the wave-shaped component 60 spring loads the shroud segments 28 radially inwardly. During engine operation, the wave-shaped component 60 will accommodate different thermal growth between the platform 30 and the aft flange 48.
As shown in
As shown in
The above description is meant to be exemplary only, and one skilled in the art will recognize that changes may be made to the embodiments described without department from the scope of the invention disclosed. For example, it will be appreciated that ring seal 58 is not limited to being installed to a high pressure shroud, but rather, it can be installed in other engine stages which exhibit similar problems and needs. Also, it is understood that the wave-shaped portion 60 could have more or less than three peaks. In fact, could have any configuration adapted to accommodate different thermal gradient between the engine parts to be sealed. Still other modifications which fall within the scope of the present invention will be apparent to those skilled in the art, in light of a review of this disclosure, and such modifications are intended to fall within the appended claims.
Number | Name | Date | Kind |
---|---|---|---|
3394919 | Catterfeld | Jul 1968 | A |
3730640 | Rice et al. | May 1973 | A |
3825365 | Peng | Jul 1974 | A |
4318668 | Chaplin et al. | Mar 1982 | A |
4573866 | Sandy, Jr. et al. | Mar 1986 | A |
5333995 | Jacobs et al. | Aug 1994 | A |
5479772 | Halila | Jan 1996 | A |
5562408 | Proctor et al. | Oct 1996 | A |
5669757 | Brackett | Sep 1997 | A |
5738490 | Pizzi | Apr 1998 | A |
5988975 | Pizzi | Nov 1999 | A |
6076835 | Ress et al. | Jun 2000 | A |
6164656 | Frost | Dec 2000 | A |
6402466 | Burdgick et al. | Jun 2002 | B1 |
20040047725 | Tomita et al. | Mar 2004 | A1 |
20060083607 | Synnott et al. | Apr 2006 | A1 |
Number | Date | Country | |
---|---|---|---|
20060159549 A1 | Jul 2006 | US |