REGULATING ORIFICE PLATE Russian patent published in 1999 - IPC

FIELD: controlling steam extraction from steam turbine. SUBSTANCE: orifice plate has orifice proper with body, rim, guide vanes between them, and turning ring with steam admission ports. With orifice closed, turning ring is pressed to body and ring under the action of steam pressure as it turns on cylindrical body of orifice plate. Equalizing chamber formed downstream of turning ring between the latter and body communicates through hole in turning ring with space upstream of it thereby equalizing pressure on turning ring within radial area of equalizing chamber. Pressure-relief chamber formed on side opposing equalizing chamber between turning ring and part of body or larger-diameter annular member it mounts communicates through channels with space downstream of orifice plate or in its guide vanes. Equalizing and regulating chambers are provided with slot-type glands arranged on cylindrical surfaces supporting the turning ring. Turning ring is greatly released due to different pressures in equalizing and regulating chambers. EFFECT: reduced power requirement of turning ring operating mechanism; reduced probability of turning ring wedging, simplified design of orifice plate. 1 dwg