Abstract: Apparatus for the release and recovery of living organisms collected or trapped on the rotary filters of water pumping stations.The apparatus comprises:on the inside of the filters, a system of two rows of multiple washing jets using water under low pressure, whose nozzles are directed towards the filter panels, so that the jets of the two rows meet one another and cooperate to form a single liquid stream;deflectors arranged at radial intervals on the outer face of the filter panels;on the outside of the filters, a channel shaped like a trough for receiving the washing water and recovering the living organisms, whose opening is oriented towards the said rows of washing jets, the edge of the opening being rounded or rotary in its lower part.

Abstract: The present invention relates to a stack, particularly an atmospheric cooling tower. The stack comprises a shell with double curvature and a bearing structure or seating for the shell; the shell is dissociated from the seating and presents in its lower part a rigid peripheral ring via which it rests on this seating. The invention is more particularly applicable to the production of atmospheric cooling towers.