Abstract: Through the analysis of the problems in an imported electro-hydraulic actuator for the inlet butterfly valve of flue gas turbine expander, a technical scheme of high reliability electro-hydraulic actuator was put forward, and the high reliability electro-hydraulic actuator was successfully developed based on the theories and methods of hydraulic drive, automatic control and reliability technology. Its technical performance, economic efficiency and safe production were comprehensively evaluated, and its efficiency was compared with that of similar products abroad

Key words: Electro-hydraulic actuator, Butterfly valve, Flue gas turbine expander