GB1472663A - Method of and apparatus for the removal of layers of pollu ting liquids floating on water - Google Patents

Abstract

1472663 Cyclone separators SOC GENERALE DE CONSTRUCTIONS ELECTRIQUES ET MECHANIQUES ALSTHOM 10 Dec 1974 [11 Dec 1973] 53384/74 Heading B2P In a method of removing a layer of polluting liquid 5, e.g. oil, floating on the surface of water, water and polluting liquid are drawn over a sill 6, Fig. 1, situated below the surface and in proximity to the layer of polluting liquid and are then led to a tangential inlet orifice 8 of a vertically disposed cyclone 4 having a ceiling 20, the water and polluting liquid being caused to flow into the cyclone through the tangential inlet orifice 8 by a suction means 9, e.g. a pump, connected to a lower outlet 18 of the cyclone, the action of the suction means 9, together with the sill 6 and the tangential inlet orifice 8, having the effect of producing a turbulent flow from the sill down to a liquid level below the surface of the water, the liquid level being stabilised at a predetermined level above the tangential inlet orifice 8, e.g. with the formation of a hydraulic pump 11, independent of the operating conditions on the surface of the water, the water and polluting liquid being thus continuously drawn through the orifice 8, the cyclone filling up to its ceiling 20 and producing a cyclonic rotation of the water and the polluting liquid and thereby causing their separation, the polluting liquid being concentrated in an axial central zone 13 of the cyclone from which it is removed by another suction means 15, e.g. a pump, through a tube 14 extending upwards from a central orifice in the ceiling 20, whereas the water, rid of the polluting liquid, is removed by the suction means 9. The sill 6 in the apparatus shown in Fig. 1 is located within a converging inlet formed by a wall 1 and the curved inside face 3 of a wall 2. The means for stabilising the liquid level above the orifice 8 may consist of one or more tangential water inlets 12, Alternatively, the liquid level may be stabilized by controlling the discharge of one of the pumps 9, 15 by means of a device for detecting the level. In a modification, Fig. 2 (not shown), a guide vane (21) is provided above the sill 6 to improve the flow of water and polluting liquid into the cyclone. In another embodiment. Fig. 3, a circular sill 22 is arranged around the cyclone 4 with vertical guide vanes 23 tangential to the body of the cyclone and directing the water and polluting liquid towards a plurality of tangential inlet orifices of the cyclone. The rate of flow into the cyclone is in this case adjusted by means of water inlet orifices 25 in the lower part of the sill 22. The apparatus may be used for purifying water in narrow spaces, e.g. in ports, between the hulls of boats or between other obstacles and may be maintained at a predetermined immersion level by floats, not shown. In stretches of choppy water where waves could momentarily uncover the sill and the cyclone inlet orifice and let air into it, the apparatus may be fitted with inwardly hinged flap devices which automatically close the inlet orifice if there is no liquid pressure outside it.