Device for the removal of a liquid layer on water

In floating apparatus capable of removing liquid pollutant floating on the surface of a still body of water while in a stationary condition relative to the latter, a cyclone composed of a casing defining a cyclone chamber and having an enlarged end and a reduced end, the portion of said casing defining the enlarged end of the chamber having an inlet orifice for entry of a water-pollutant mixture into said chamber, a guide wall connected to said casing at said inlet orifice for directing said mixture tangentially into said chamber, a dam mounted on said cyclone casing having a water-pollutant overflow sill spaced from said casing, said dam forming with said cyclone casing a substantially closed water compartment for providing a cavity in said body of water and containing said inlet orifice, said dam in the use of the apparatus being normally submerged with its sill situated below but close to the free surface of the body of water to create with the cavity provided by said compartment a hydraulic drop with flow of water and pollutant to discharge a continuous flow of water and pollutant into said compartment to form in said compartment before the inlet orifice a level of the mixture independent of and lower than that of the free surface of the body of water being purified, the dam having a height enabling the level of the mixture in said compartment to be constantly higher than said cyclone inlet orifice whereby a continuous mixture of water and pollutant may be fed through such inlet orifice, first suction means connected to said reduced end of said cyclone casing for filling said cyclone chamber up to its ceiling with the liquid mixture from said compartment and for producing in such mixture a cyclonic rotation capable of separating the water and pollutant by centrifugation and for concentrating the pollutant in an axial central zone of the cyclone, second suction means connected to said enlarged end of said cyclone casing for removing the concentrated pollutant through the ceiling of said cyclone chamber, said first suction means removing the water freed of pollutant through said reduced end of said cyclone casing.