STEAM TURBINE SINGLE SHELL EXTRACTION LP CASING

摘要

A single shell extraction casing includes a stepped shell which is formed from a plurality of circumferentially shaped ledge rings located along the axial length of the casing between turbine stages and covered by a casing wrapper. The stepped shell has a simpler construction than the double shell configuration of a conventional turbine extraction casing. Pockets for supporting diaphragms between the multiple stages in the stepped single shell extraction casing are connected directly between ledge rings so they are away from the casing wrapper. This decreases the amount of welding and manufacturing complexity needed to install the diaphragm support pockets.