Apparatus for controlling the flow of leakage and cooling air of a rotor of a multi-stage turbine

Claim 1

A multi-stage turbine comprising a casing, a rotor in said casing for extracting energy from an inlet fluid stream and discharging the fluid stream, at a low pressure discharge end of the rotor, at a given direction to a subsequent turbine stage, said rotor including a plurality of spaced rotor blades and a peripheral shroud on said blades to cover the blades, said shroud having holes for passage therethrough of cooling air which flows radially outwards from the blades, said shroud and casing forming a leakage path for flow of leakage air between the shroud and casing, and a stationary guide assembly secured to said casing and extending between said shroud and casing, said guide assembly including guide grid means for receiving said cooling air and said leakage air to combine the same and guide it for discharge from the rotor to the subsequent turbine stage at said direction substantially corresponding to the angle of discharge of said fluid stream from said rotor, said guide assembly being axially offset relative to said rotor blades at the low pressure discharge ends thereof.