STEAM TURBINE EXTRACTION CONTROL SYSTEM Russian patent published in 2003 - IPC

FIELD: extraction turbines. SUBSTANCE: system is designed for turbines with heating and production extractions. Said system has high pressure part servomotor and low pressure part servomotor with limit switches connected with speed and steam extraction controls furnished with setters, shutoff valve servomotor connected with spools of safety automatic control device and safeguard to control extractions made in form of extraction pressure control relay one of which has first limit operation setter and others, higher limit operation setter. Second limit pressure relays are connected with spools of safety automatic control device. Logic unit includes OR gate with direct and inverted outputs, relays-repeaters and two AND gates, first of which is provided with inverted output. First limit pressure relays are connected to inputs of OR gate, and direct outputs of OR gate are connected to inputs of AND gates and invented output is connected to first control input of change-over switch, and limit switches of low pressure part servomotor are connected through relays-repeaters to other inputs of first AND gate, and output of first AND gate is connected to second control input of change-over switch. Inverted output of first AND gate is connected to input of second AND gate, and output of second AND gate is coupled with third control input of change- over switch, and outputs of change-over switch are connected with setters of extraction and speed control. For turbines with both heating and other extractions, safety device is furnished with at least two groups of additional pressure relays in extractions with pressure level higher than that heating extractions, with operation settings to third and higher fourth limits and additional OR gate with direct and inverted outputs to inputs of which third limit pressure relays are connected. Direct output of additional OR gate is connected to third control input of change-over switch, and inverted output, to one of inputs of first OR gate. Fourth limit pressure relays are connected with spools of safety automatic control device. Output of second AND gate is coupled with third control input of change-over switch through additional OR gate. Such design of system enlarged range of operation of turbines with heating and other chambers and extractions which require protection against pressure rise. EFFECT: provision of reliable protection in operation. 2 dwg