A pulsator valve device for generating a pulsed flow of a liquid (L) through an outlet (8B) of a passage (8) for the liquid (L) comprising a) at least one valve element (9) which is moveable in a repetitive movement comprising an opening movement from a closed state for closing the outlet (8B) to at least one opened state for opening the outlet (8B) and a closing movement from an opened state to the closed state, b) at least one actuator element (10) and c) at least one resilient first bellows (13) having folds (131) and an inner space (130) being confined in a liquid tight manner and being connected with the actuator element (10) and with the valve element (9), d) wherein the actuator element (10) has at least one hydraulic surface (A2) which can be put under the liquid pressure (P1) of the liquid (L) in the passage (8) on one side and under the internal pressure (P0) prevailing in the inner space (130) of the first bellows (13) on the other side, e) wherein the first bellows (13) is provided with a liquid exchange channel (22, 25, 14) for its inner space (130) allowing for liquid (L) to flow out of the inner space (130) when the volume of the inner space (130) is reduced during compression of the first bellows (13) and allowing for liquid (L) to flow into the inner space (130) when the volume of the inner space (130) is increased during decompression of the first bellows (13), and f) wherein the first bellows (13), during at least part of the time when the valve element (9) is in the closed state and/or in at least part of the opening movement of the valve element (9), is compressed by a hydraulic force being generated at the hydraulic surface of the actuator element (10) due to the pressure difference between the liquid pressure (P1) and the internal pressure (P0) and, in at least part of the closing movement of the valve element (9), is decompressed by a resilient force of the first bellows (13), when due to a flow of liquid (L) into the inner space (130) throug
