Electric actuator for valves and emergency shutoff valve Emergency release valve and method for diagnosing abnormality of electric actuator for valve

摘要

PROBLEM TO BE SOLVED: To provide an electric actuator for a valve in which the valve can be positively full-opened state or full-closed state at the time of emergency and provide an emergency shut-off valve*emergency relief valve.SOLUTION: This invention relates to an electric actuator for opening or closing a valve by a motor having a power supply circuit for converting an AC power supply to a DC power supply. When this power supply circuit is connected to a secondary cell through a secondary cell charging circuit and the secondary cell after charging is connected to a DC motor and the actuator is finely operated under application of power force charged in the secondary cell within a range not generating any passage leakage at the valve or an angle within a range satisfying a flow rate, a current of the DC motor is read by a current detector and when an irregular current value is measured, it is diagnosed that irregular state is generated at a mechanism part of the electric actuator for valve including DC motor or a valve having the actuator fixed thereto.SELECTED DRAWING: Figure 1