Abstract: A new device for the displacement of fluids, has at least one essentially revolving covering, which has the form of a trunk of a cone or pyramid, which minor base has an inlet or catch-basin inlet for fluids. The revolving covering contains a core which is concentric therewith, and which has a surface of revolution non-parallel to the wall of the covering and which converges progressively towards the same so as to define therebetween an annular conduit that gets gradually narrower towards the major base of the above-mentioned revolving convering, which base forms an annular outlet or discharge socket for the fluid.