Abstract: A specific feature of the present invention comprising a water-permeable screen mounted on a perforated suction pipe is that located therein between the screen and the pipe are partitions the length of contour of which resting on the screen decreases towards the perforated pipe inlet, the screen surface defined by two adjacent partitions being superior to that of the pipe between the same partitions, whereas the partitions on said pipe are disposed in a manner such that the hydraulic resistances therebetween will increase in proportion to the distance from the partitions to the perforated pipe inlet.