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