SERVOMOTOR OF TURBINE FINAL-CONTROL VALVE UNIT Russian patent published in 2006 - IPC F01D17/20 

FIELD: mechanical engineering; turbines.

SUBSTANCE: invention relates to servomotor of final-control valve unit of steam turbine featuring high parameters of steam and the following sequence of valve opening: upper valve opens first and lower valve opens second. Proposed servomotor contains two rods first of which passes through servomotor housing in its lower part and is directly connected with rod of lower valve, second rod is rigidly connected with axle of leverage connected with rod of upper valve, contact surfaces for interaction of rods in drain space of housing, and concentrically installed pull-back outer and inner springs thrusting, respectively against piston of servomotor and opposite plate. Second rod is made hollow. First rod passes inside second rod and both rods come out in upper part of housing. Hollow rod is connected with piston of servomotor. Plate is key-mounted on first rod in drain space for interaction of piston and plate through key. Axle of leverage is located in through slot of first rod with clearance relative to slot with provision of interaction of rods through contact surfaces and guaranteed closing of valves. Hollow rod is provided with opposite slots in plate mounting place to provided vertical displacement of first rod. Proposed design of servomotors of final-control valve unit provides reliable operation of valve unit preventing wedging of rods owing to increased guide surfaces for servomotor rods and guarantees such preset sequence of opening of valves at which upper valve is first to open, and lower valve opens afterwards.

EFFECT: provision of ease of adjustment between contact surfaces with interaction of rods of servomotor and compensation of thermal expansion.

2 cl, 3 dwg