Patent ID: 6309177
Filing Date: 2001-10-30
Classification: F01D,F05D,Y10T

Abstract:
In a gas turbine engine having:a longitudinal engine axis; andat least one turbine disposed on a shaft assembly at a predetermined axial position for rotation about a longitudinal shaft axis, the turbine including a hub with a circumferentially spaced apart array of turbine blades each having a radially outward blade tip, the blade tips during turbine rotation defining a tip surface of rotation concentric the shaft axis;the shaft axis being radially eccentric the engine axis at the axial position of the turbine an assembly eccentricity within the range between zero and a predetermined allowable assembly tolerance; the improvement comprising:a static outer engine housing assembly having an engine housing flange with a cylindrical internal surface concentric the engine axis;a static turbine shroud having a shroud flange with an external cylindrical surface removably mounted to the engine housing flange and having an internal turbine shroud surface of rotation matching the blade tip surface of rotation, the shroud external and internal surfaces being non-eccentric relative to one another; and a concentricity ring with: an outer cylindrical surface mating the internal cylindrical surface of the engine housing flange; and an inner cylindrical surface mating the external cylindrical surface of the turbine shroud flange; the outer and inner cylindrical surfaces of the concentricity ring being eccentric a ring eccentricity within the range between zero and said predetermined allowable assembly tolerance.