Patent ID: 8202037

Claim:
A steam turbine, comprising: a rotor arranged along a rotational axis of the turbine having a thrust balance piston and a plurality of rotor blades; an inner casing enclosing a live steam feed duct; a plurality of stator blades arranged in the inner casing such that a flow passage having a plurality of blade stages is formed along a flow direction of the turbine where each blade stage is comprised of a row of rotor and stator blades; a communication passage arranged between the inner casing flow passage downstream of one of the plurality of blade stages and a thrust balance piston antechamber, the thrust balance piston antechamber is disposed between the thrust balance piston of the rotor and the inner casing; a cross-return passage completely arranged in the inner casing between a seal chamber of the rotor and the inner casing and an inflow chamber located downstream of one of the plurality of blade stages in the flow passage; and an outer casing having a live steam duct that rotably supports the rotor and surrounds the inner casing.