Patent ID: 8591185

Claim:
A diffuser for an exhaust steam housing adjacent a last stage row of buckets fixed to a rotor in a steam turbine, each bucket in the last stage row of buckets having a platform portion and an airfoil portion, the diffuser comprising: an annular inner diffuser ring and an outer annular diffuser ring defining a flow path for steam exiting the last stage row of buckets in a substantially axial direction at a diffuser inlet and turning substantially ninety degrees to a diffuser outlet; a first portion of the inner annular ring extending in a downstream direction beyond said last stage row of buckets substantially parallel to a center axis of the rotor, said first portion having a length dimension in the downstream direction from a radial center line of said last stage row of buckets in a range of between 0.40 and about 0.70 of a center line radial length from the platform portion to a radially outer tip of any bucket in the last stage row of buckets.