Diaphragm for turbomachines and method of manufacture

Abstract

A turbine diaphragm includes an annulus of static blades and an outer diaphragm ring surrounding the annulus of static blades and welded to the outer platforms. Each static blade has an inner platform, an aerofoil, and an outer platform. The inner platforms serve the function of an inner diaphragm ring, thereby reducing material and manufacturing costs. Furthermore, confronting edges of the inner platforms have an interference fit with each other and the aerofoils are in a state of torsional stress between the inner and outer platforms. The latter two features improve the dynamic characteristics of the diaphragm.