Gas turbines typically include a compressor section, a combustion section, and a turbine section. The compressor section pressurizes air flowing into the turbine. The pressurized air discharged from the compressor section flows into the combustion section, which is generally characterized by a plurality of combustors disposed in an annular array about the axis of the engine. Air entering each combustor is mixed with fuel and combusted. Hot gases of combustion flow from the combustion liner through a transition piece to the turbine section to drive the turbine and generate power. The turbine section typically includes a turbine rotor having a plurality of rotor disks and a plurality of turbine buckets extending radially outwardly from and being coupled to each rotor disk for rotation therewith. The turbine buckets are generally designed to capture and convert the kinetic energy of the hot gases of combustion flowing through the turbine section into usable rotational energy.
The turbine section also includes a substantially cylindrical turbine casing configured to contain the hot gases of combustion. The turbine casing typically supports a turbine shroud designed to encase or shroud the rotating components of the turbine rotor. As is generally understood, the turbine shroud may be formed from a plurality of shroud sections or tiles that, when installed around the inner circumference of the turbine casing, abut one another so as generally define a cylindrical shape surrounding the turbine rotor and forming the outer perimeter of the hot gas path of the turbine section. As such, the shroud tiles generally serve as a heat shield for the turbine casing.
Due to constant exposure with the hot gases of combustion flowing through the turbine section, the shroud tiles of the turbine shroud must often be repaired and/or replaced due to oxidation and/or other damage. For instance, seals, such as cloth seals, typically extend between seal slots defined in the sides of adjacent shroud tiles to seal the gap defined between the shroud tiles. Over time, the seals may fail leading to hot gas ingestion between adjacent shroud tiles. As such, the sides of each shroud tile may often be subject to heavy oxidation, particularly within the seal slots. To repair such damaged shroud tiles, conventional repair methods typically involve adding material using a welding and/or brazing process to build up the damaged side surfaces of the shroud tiles. Once the side surfaces are built up with the added material, the surfaces must then be ground down to establish the proper dimensions of the shroud tile and new seal slots must be machined into the surfaces. As such, this repair method is very time and labor intensive, thereby making it very costly to perform.
In addition, due to the volume of braze and/or weld material that must be used during the performance of the conventional repair method, the shroud tiles must be positioned upright (i.e., with one side of the shroud tile facing up) to build up the added material along the side of the shroud tile. Accordingly, each shroud tile may only be repaired one side at a time, further increasing the amount of time required to repair each shroud tile. As such, it is often the case that, when both sides of shroud tile need to be repaired, the damaged shroud tile may simply be scrapped to avoid the excessive time and costs needed for completely repairing the shroud tile.
Accordingly, a new method for repairing damaged shroud tiles that is more efficient and less costly would be welcomed in the technology.
USPTO Backgrounds
USPTO Backgrounds