Patent ID: 7931252

Claim:
A steam valve comprising: a valve body; a valve seat; and a valve rod provided for the valve body, the valve body having a bottom portion to which a recessed portion is formed, the recessed portion having an edge, wherein a range of a curvature radius R of the valve body is set to R =(0.52 to 0.6) Do and a range of a curvature radius r of the valve seat is set to r≧0.6Do in which Do is a valve seat diameter of a valve seat, and wherein the edge of the recessed portion is positioned on an upstream side of a major axis line connecting the center of the curvature radius of the valve body with the center of the curvature radius of the valve seat so that the edge forms the minimum path area of a steam path between the valve body and the valve seat, in which a range of a maximum valve lift La of the valve body combined with the valve rod is set to La =(0.25 to 0.35) Do.