Steam driven power plant with de-superheater aided safety valve - has servo-control for de-superheater, opened fully if safety valve lifts

摘要

The steam driven power plant with desuperheater assisted safety valve basically comprises a boiler supplying a turbine, with a bypass line (2) embodying a desuperheater (3, 4, 5) to protect machinery further downstream. A controller (6) with pressure (7) and temp. (8) sensors regulates throttle (3) and water injection (4) valves of the desuperheater via servo units (9, 10) by varying (12, 13) fluid supply pressure to them from a reservoir (11). Springs (22) in the servos tend to open the valves. A safety valve (14) in the live steam line (1) is so connected (15) to a quick release valve (16) from the servos that any flow through the former valve releases the servo pressure. Throttles (18, 19) in the servo lines prevent release valve feathering.