STEAM TURBINE AND METHOD FOR ELIMINATING BENDING OF ROTOR SHAFT

摘要

PURPOSE: A steam turbine and a method for eliminating bending of a rotor shaft are provided to eliminate or minimize thermal bending caused by non-uniform heat distribution at the circumference of a rotatable component, resulting from the frictional contact between a brush seal and the rotatable component. CONSTITUTION: A steam turbine comprises a rotatable component(11) including a rotor shaft(12) having a rotor shaft surface; a fixed component(17) about the rotatable component; a brush seal(26) carried by the fixed component for sealing engagement with the rotatable component; at least a pair of wheels(14) on the rotatable component spaced axially from one another. The rotatable component includes a plurality of buckets(16) spaced circumferentially from one another on each of the wheels and a unit for inhibiting non-uniform circumferential heat transfer to the rotor shaft surface due to heat generated by frictional contact between the brush seal and the rotatable component thereby to eliminate or minimize bending of the rotatable component. The inhibiting unit includes an annular platform(40) projecting radially outwardly of the rotor shaft surface at an axial location between the wheels. The brush seal is disposed between the buckets on the wheels and the brush seal engages a sealing surface on the platform radially outwardly of the rotor shaft surface.