Patent ID: 8018709

Claim:
An actuator for control valves and/or shut-off devices, the actuator comprising: an electromagnetic drive unit comprising a moving coil, said moving coil including a magnet coil and a cylindrical solenoid plunger, said cylindrical solenoid plunger having a resetting spring, said moving coil being mounted for movement such that said moving coil is movable to opposite end positions and a plurality of positions in between said end positions along an axial direction, whereby said moving coil defines an axially movable part of said electromagnetic drive unit; an actuating element for acting on a closing or opening element, said actuating element comprising a push or pull rod, said push or pull rod being connected to one of said permanent magnet and said moving coil such that said push or pull rod moves from an operative position to an inoperative position, said resetting spring maintaining said push or pull rod in said inoperative position; an electronic actuating amplifier receiving a command signal, said command signal defining a predetermined position of said actuating element; an electrical or electronic position controller, said position controller detecting an actual position of said actuating element, said position controller transmitting the actual position of said actuating element to said electronic actuating amplifier, said electronic actuating amplifier supplying a working voltage, which can be varied between a minimum and a maximum for actuating the actuating element, to said moving coil based on feedback, said electronic actuating amplifier increasing said working voltage to said maximum until said actual position of said actuating element received from said position controller is at said predetermined position, said maximum of said working voltage being able to be applied in each of said opposite end positions and said plurality of in between positions to selectively hold said electromagnetic drive unit in each of respective said positions.