Patent ID: 7179052

Claim:
A nozzle diaphragm assembly comprising: a diaphragm outer ring having an inner groove radially opened toward an inner side continuously along an inner circumferential direction of the diaphragm outer ring; a diaphragm inner ring having an outer groove radially opened toward an outer side continuously along an outer circumferential direction of the diaphragm inner ring; and a nozzle blade having an outer insertion portion for the diaphragm outer ring provided on one end and an inner insertion portion for the diaphragm inner ring provided on the other end, wherein the inner groove of the diaphragm outer ring and the outer insertion portion of the nozzle blade are shaped to be fitted to each other only in the inner circumferential direction of the diaphragm outer ring, and the outer groove of the diaphragm inner ring, and the inner insertion portion of the nozzle blade are shaped to be fitted to each other only in one of the outer circumferential direction and a radial direction of the diaphragm inner ring, and wherein the outer insertion portion of the nozzle blade includes a protruded hook portion, which is protruded from the outer insertion portion, provided only at an upstream side of a fluid flow of the outer insertion portion, and a stepped block portion which includes at least one recessed portion and at least one projecting portion, provided continuously to the protruded hook portion, in which the protruded hook portion and the stepped block portion extend in a circumferential direction to be fitted with the inner groove of the diaphragm outer ring.