Patent Application
20130202433
The subject matter disclosed herein relates to gas turbine rotors and, more particularly, is concerned with a seal assembly for sealing coolant passageways in turbine rotor blades disposed in the periphery of a turbine rotor disc.
A typical gas turbine has a rotor (wheel) with a number of blades (buckets) distributed around the circumference of the rotor. The blades may be secured to the rotor using a conventional dovetail configuration. The blades are driven by hot gas from the combustion chamber and are cooled using a coolant that flows through passages in the blades. It is important to avoid the hot gases from coming into contact with the rotor.
A variety of seal configurations have been developed to prevent the hot gases from coming into contact with the rotor. In some cases a seal assembly may be positioned about the rim of rotor to seal off the hot gases. In some applications a wire seal may be disposed in a groove in the rotor to provide a more effective seal. Another approach is to provide a seal plate comprising of a number of seal plate segments each having seal wings that isolate the rim cavity from the hot gas path. The seal plate segments may be connected to the rotor using hooks and locking pins that capture the seal plates and prevent them from slipping out of the bladed rotor assembly when the turbine is not spinning, respectively. Wire seals can be used around the seal plates. The segmented seal plates usually rely on tight tolerances to control leakage area.
These devices have the disadvantage that, during installation, it is difficult to maintain the correct position of a wire seal while installing segmented seal plates onto the rotor.
In accordance with one exemplary non-limiting embodiment, the invention relates to a seal assembly for use with a turbine having a rotor and at least one turbine blade. The seal assembly includes a plurality of seal plate segments; a plurality of retainers disposed on a rotor flange on the rotor and or buckets; a seal member disposed between the retainers and the plurality of seal plate segments; and at least one attachment member disposed through the rotor flange that limits radial displacement of the seal plate segments.
In another embodiment, a method for providing a seal for a turbine having a rotor and at least one turbine blade is provided. The method includes positioning an inner diameter subassembly in a chamber formed by a rotor flange and a blade flange. The method further includes displacing the inner diameter subassembly in a radial direction within the chamber; and securing the inner diameter subassembly within the chamber.
In another embodiment, a turbine having a rotor with a rotor flange and a plurality of turbine blades each having a blade flange is provided. The rotor flange and the blade flange define a chamber. The turbine includes a plurality of seal plate segments disposed in the chamber and a plurality of retainers disposed on the rotor flange. A seal member that is disposed between the first plurality of retainers and the plurality of seal plate segments is provided. At least one attachment member that is disposed through the rotor flange to limit radial displacement of the seal plate segments is also provided.
Other features and advantages of the present invention will be apparent from the following more detailed description of the preferred embodiment, taken in conjunction with the accompanying drawings which illustrate, by way of example, the principles of the invention.
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Disposed in the chamber 16 is a seal assembly 18 that may include a seal plate segment 19. The seal plate segment 19 may include an upper seal arm 21 and a plate segment flange 23. The seal plate segment 19 may also be provided with a beveled end 25. The seal assembly 18 has a radial dimension that is greater than the radial dimension of the opening 15 and smaller than the radial dimension of the chamber 16.
The seal assembly 18 may also include an outer diameter wire seal 27, and an inner diameter wire seal 29. The outer diameter wire seal 27 and the inner diameter wire seal 29 may be of any of a variety of cross-section such as for example circular, hexagonal, octagonal, and the like. Additionally, the outer diameter wire seal 27 and the inner diameter wire seal 29 may be a single filament or multiple filaments braided into a rope. The outer diameter wire seal 27 and the inner diameter wire seal 29 may be made of any of a number of known materials as necessary to survive in this operating environment such as high temperature steels, nickel alloys, ceramic, or a combination of any of the materials.
The seal assembly 18 may also include an outer diameter retainer 31 and inner diameter retainer 33 disposed at the ends of the seal plate segment 19. The seal assembly 18 may be disposed within the chamber 16 and an attachment member such as a pin 35 may be provided to limit the radial displacement of the seal assembly 18 within the chamber 16. The inner diameter retainer 33 may have a C-shaped cross-section and may include a seat portion 37 adapted to receive one of the ends of the seal plate segment 19. One or more inner diameter retainers 33 provide a carrier ring that facilitates the use of the inner diameter wire seal 29 with a plurality of seal plate segments 19. The inner diameter retainer 33 could be a ring, split in one location to allow it to be expanded over the rotor flange and compressed inside the rotor flange. Optionally, the inner diameter retainer 33 may be provided with a recess 39 to accommodate the inner diameter wire seal 29. Similarly, the outer diameter retainer 31 may include a seat portion 41 adapted to receive and end of the seal plate segment 19 and may be provided with a recess 43 to accommodate the outer diameter wire seal 27. The inner diameter retainer 33 in the outer diameter retainer 31 may be made of materials suitable for use in a turbine environment. The materials may include various alloys of steel, nickel, and coatings to protect the components.
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This written description uses examples to disclose the invention, including the best mode, and also to enable any person skilled in the art to practice the invention, including making and using any devices or systems and performing any incorporated methods. The patentable scope of the invention is defined by the claims, and may include other examples that occur to those skilled in the art. Such other examples are intended to be within the scope of the claims if they have structural elements that do not differ from the literal language of the claims, or if they include equivalent structural elements with insubstantial differences from the literal languages of the claims.
