Static blade for a turbine diaphragm and associated turbine diaphragm

Abstract

Static blade for an axial flow turbine comprising an aerofoil portion having a leading edge, a trailing edge, a pressure side and a suction side and radially inner and outer reinforcement portions integral with said aerofoil portion. Each reinforcement portion closely follows the shape of the section of the aerofoil portion.

1 . Static blade for an axial flow turbine comprising:
 an aerofoil portion having a leading edge, a trailing edge, a pressure side and a suction side,   radially inner and outer reinforcement portions integral with said aerofoil portion,   wherein each reinforcement portion ( 46 ,  48 ) closely follows the shape of the section of the aerofoil portion.   
     
     
         2 . Static blade according to  claim 1 , wherein each reinforcement portion has a section substantially bigger than the section of the aerofoil portion, having a rounded and enlarged shape corresponding to the leading edge surrounding the leading edge of the aerofoil portion and a thinner part corresponding to the trailing edge surrounding the trailing edge of the aerofoil portion. 
     
     
         3 . Static blade according to  claim 1 , made of an alloy steel material. 
     
     
         4 . Static blade according to  claim 3 , wherein the alloy steel material comprises 12% of chrome. 
     
     
         5 . An axial flow turbine diaphragm construction comprising:
 an annulus of a plurality of identical static blades according to  claim 1 ,   an inner and outer spacer bands having through-holes therein shaped to receive the inner and outer reinforcement portions of each static blade, and   a radially inner and outer diaphragm rings surrounding the annular spacer bands.   
     
     
         6 . Axial flow turbine diaphragm construction according to  claim 5 , wherein each reinforcement portions are welded to the corresponding spacer band by welds. 
     
     
         7 . Axial flow turbine diaphragm construction according to  claim 2 , wherein of the welds are located at each leading and trailing edges of each reinforcement portions. 
     
     
         8 . Axial flow turbine diaphragm construction according to  claim 5 , wherein the inner spacer band is welded to the inner ring and the outer band is welded to the outer ring.