Patent Application
20130045090
The subject matter disclosed herein relates to the art of turbomachines and, more particularly, to a seal assembly that extends between two stationary turbomachine components.
In a typical can-annular gas turbomachine, combustors are arranged in an annular array. The combustors receive a supply of pressurized air from a compressor portion of the turbomachine, and a supply of fuel. The pressurized air and fuel are mixed to form a combustible air/fuel mixture. The air/fuel mixture is ignited to form hot gases that are directed into a turbine portion of the turbomachine. Thermal energy from the hot gases is converted to mechanical, rotational energy in the turbine portion.
The hot gases are passed along a hot gas path that extends between various stationary members of the turbomachine. For example, combustion gases pass from the combustors through a transition piece and toward a first stage of the turbine portion. The transition piece is secured to the turbine portion at an interface region. A seal is positioned in the interface region to prevent any escape of the hot gases. Often times the transition piece and the turbine portion are formed from different materials having distinct thermal rates of expansion. As such, after exposure to the hot gases a gap at the interface region expands. Over time, the seal becomes fatigued and is no longer capable of spanning the gap during all operating conditions.
According to one aspect of an exemplary embodiment, a turbomachine seal assembly includes a base member, a rocker arm pivotally mounted to the base member, and a seal element fixedly mounted to the rocker arm. The seal element is configured and disposed to selectively shift relative to the base member.
According to another aspect of the exemplary embodiment, a turbomachine includes a first fixed member having an outlet, a second fixed member having an inlet fluidly connected to the outlet of the first fixed member, and a seal assembly extending between the first fixed member and the second fixed member. The seal assembly includes a base member fixedly mounted to one of the first fixed member and the second fixed member, a rocker arm pivotally mounted to the base member, and a seal element fixedly mounted to the rocker arm. The seal element is configured and disposed to selectively shift relative to the base member as the first fixed member shifts relative to the second fixed member.
According to yet another aspect of the exemplary embodiment, a turbomachine includes a turbine portion having a turbine casing defining a turbine inlet, a transition piece operatively connected to the turbine portion. The transition piece includes a transition piece outlet coupled to the turbine casing at the turbine inlet. A seal assembly extends between the transition piece outlet and the turbine inlet. The seal assembly includes a base member fixedly mounted to one of the transition piece and the turbine portion, a rocker arm pivotally mounted to the base member, and a seal element fixedly mounted to the rocker arm. The seal element is configured and disposed to selectively shift relative to the base member as the transition piece shifts relative to the turbine portion.
These and other advantages and features will become more apparent from the following description taken in conjunction with the drawings.
The subject matter, which is regarded as the invention, is particularly pointed out and distinctly claimed in the claims at the conclusion of the specification. The foregoing and other features, and advantages of the invention are apparent from the following detailed description taken in conjunction with the accompanying drawings in which:
The detailed description explains embodiments of the invention, together with advantages and features, by way of example with reference to the drawings.
With initial reference to
The hot gases pass initially toward a first stage 15 having a plurality of circumferentially spaced buckets 16 mounted on a first-stage roller or welder wheel 18 and a plurality of circumferentially spaced stator vanes 20. The hot gases pass to a second stage 21 having a plurality of buckets 22 mounted on a roller or welder wheel 24 and a plurality circumferentially spaced stator vanes 26 and on to a third stage 27. Third stage 27 includes a plurality of circumferentially spaced buckets 28 mounted on a third stage roller or welder wheel 30 and a plurality of circumferentially spaced stator vanes 32. Of course, it will be appreciated that the number of stages present within turbine portion 10 can vary. It will also be appreciated that stator vanes 20, 26, and 32 are mounted on, and fix to, turbine casing 11, while buckets 16, 22, and 28, and wheels 18, 24 and 30 form part of the turbine welder. Turbine portion 10 is also shown to include a plurality of spacers 34 and 36 arranged between welder wheels 18, 24 and 30. Finally, it should be appreciated that compressor discharge air enters turbine portion 10 at a region 37 disposed radially inward of first stage 15. As such, air within region 37 is at a higher pressure than the hot gases following along hot gas path 14. At this point it should be understood that the above described structure is provided for the sake of completeness and to aide in better understanding the exemplary embodiment which is directed to a seal assembly 50 arranged between transition piece 12 and turbine casing 11.
As best shown in
In accordance with one aspect of the exemplary embodiment illustrated in
Reference will now be made to
First base member 154 includes a base portion 173 that is mounted to inlet flange 70. Base portion 173 extends to a first pivoting member 174 having a substantially circular outer surface 175. Similarly, base member 156 includes a base portion 179 that is mounted to outlet flange 62. Base portion 179 extends to a second pivoting member 180 having a substantially circular outer surface 181. Rocker arm 165 includes a first pivoting element 185 that pivots over second pivoting member 180 and a second pivoting element 186 that pivots or travels over first pivoting member 174. First and second pivoting elements 185 and 186 are connected to a cantilevered mounting element 189 that links rocker arm 165 with seal element 168. In a manner similar to that described above, seal element 168 includes a first seal portion 192 coupled to a second seal portion 194 through a connecting member 196. First seal portion 192 includes first and second seal elements 198 and 199. Second seal element 199 extends into first seal receiving portion 63 while first seal element 198 seals against outlet flange 62. Second seal portion 194 includes first and second seal elements 202 and 203. Second seal element 203 extends into second seal receiving portion 73 while first seal element 202 seals against inlet flange 72. With this arrangement, rocker arm 165 pivots back and fourth over first and second pivoting members 174 and 180 to adjust for any relative movement of transition piece 12 relative to turbine casing 11.
At this point it should be understood that the exemplary embodiments describe a seal assembly that pivots about a pivoting member to ensure that a seal element remains in contact with mating surfaces despite dimensional changes of adjacent members. That is, thermal expansions and contractions can open an interface region between to mating surfaces. The seal assembly in accordance with the exemplary embodiments pivots as one, another, or both of the mating surface undergo dimensional changes. It should also be understood that while described as sealing an interface between a transition piece and a turbine portion of a turbomachine, the seal assembly in accordance with the various aspects of the exemplary embodiment can be used to seal between mating surfaces of other components that undergo dimensional changes.
While the invention has been described in detail in connection with only a limited number of embodiments, it should be readily understood that the invention is not limited to such disclosed embodiments. Rather, the invention can be modified to incorporate any number of variations, alterations, substitutions or equivalent arrangements not heretofore described, but which are commensurate with the spirit and scope of the invention. Additionally, while various embodiments of the invention have been described, it is to be understood that aspects of the invention may include only some of the described embodiments. Accordingly, the invention is not to be seen as limited by the foregoing description, but is only limited by the scope of the appended claims.
