Abstract: A valve actuator (10) includes an electric motor (12) that opens, and also closes if need be, the valve via a gearing (15). A voltage supply device (19) has an input rectifier circuit and a buffer device (24) connected thereto, for example in the form of a capacitor C. From the voltage buffered by the capacitor C, a motor control circuit (25) obtains the energy for operating the electric motor (12). To prevent the valve (11) from being kept open too long after the voltage supply at the input (20) has been switched off, a switch-off device (34) is provided, which, after elimination of the voltage at the input (20), cuts off the energy flow from the voltage buffer device (24) to the electric motor (12).

Abstract: The valve series includes a plurality of valve types (A, B, C) with valves of different size and type, wherein a plurality of valve types, preferably all valves types (A, B, C) of the valve series (11) have uniform valve actuators (21), wherein the valve closure members (19) of the valves (10, 12, 13) perform the same opening stroke, wherein they can be formed differently, however, and in particular can have different diameters. The closing springs (20) of the different valve types (A, B, C) can also have different characteristic curves and can be of different thicknesses.

Abstract: A valve actuator (10) has a damping circuitry including a capacitive damping circuit (37), which is activated in the event of generator operation of the stepper motor (18). The damping circuitry, together with the motor winding (26), forms a resonance assembly LCR, which has the effect of stabilising and regulating rotational speed. The rotational speed of the stepper motor (18), running in generator operation, is held constant within limits, specifically without the control intervention of control circuitry. Therefore, the damping circuitry can operate even in the currentless state of the control system and is reliable regardless of external current supply. Fast closing is achieved, and excessively long post-running of the motor (18) is reliably prevented.

Abstract: A valve actuator (10) has a damping circuitry including a capacitive damping circuit (37), which is activated in the event of generator operation of the stepper motor (18). The damping circuitry, together with the motor winding (26), forms a resonance assembly LCR, which has the effect of stabilising and regulating rotational speed. The rotational speed of the stepper motor (18), running in generator operation, is held constant within limits, specifically without the control intervention of control circuitry. Therefore, the damping circuitry can operate even in the currentless state of the control system and is reliable regardless of external current supply. Fast closing is achieved, and excessively long post-running of the motor (18) is reliably prevented.

Abstract: A valve actuator (10) includes an electric motor (12) that opens, and also closes if need be, the valve via a gearing (15). A voltage supply device (19) has an input rectifier circuit and a buffer device (24) connected thereto, for example in the form of a capacitor C. From the voltage buffered by the capacitor C, a motor control circuit (25) obtains the energy for operating the electric motor (12). To prevent the valve (11) from being kept open too long after the voltage supply at the input (20) has been switched off, a switch-off device (34) is provided, which, after elimination of the voltage at the input (20), cuts off the energy flow from the voltage buffer device (24) to the electric motor (12).

Abstract: The valve series includes a plurality of valve types (A, B, C) with valves of different size and type, wherein a plurality of valve types, preferably all valves types (A, B, C) of the valve series (11) have uniform valve actuators (21), wherein the valve closure members (19) of the valves (10, 12, 13) perform the same opening stroke, wherein they can be formed differently, however, and in particular can have different diameters. The closing springs (20) of the different valve types (A, B, C) can also have different characteristic curves and can be of different thicknesses.