GATE VALVE ACTUATOR AND METHOD

摘要

A gate valve actuator is disclosed, comprising a stem (4) which is movable linearly in an actuator housing (10) connectable to the gate valve, the stem acting on the gate valve to shift the gate valve between open and closed positions, respectively, wherein the stem (4) is driven by a motor in a first direction into a steady state operation position, and in said position the stem is biased in a second opposite direction towards a shutdown position by means of a spring member (14) acting on the stem (4). According to the invention, a trigger mechanism (22; 25; 29) is arranged for holding the spring member in a compressed state, the trigger mechanism comprising an electrically controllable trigger (22) which is arranged for release of the spring member (14) in result of de-energizing the electrically controlled trigger (22). A method for shifting a gate valve between a steady state operation mode and a shutdown mode by means of the gate valve actuator is also disclosed.