Patent GB-1372603-A (GB)
Title: Separating oil from oil contaminated water
IPC: B01D17/02
Filed: 1972-01-19
Abstract: 1372603 Pumping ships' bilges INTERNATIONAL POLLUTION CONTROL SYSTEMS Inc 19 Jan 1972 [22 Jan 1971 3 June 1971 1 Dec 1971] 2651/72 Heading B7M [Also in Division B1] Water from the lower part of a ship's bilge is discharged directly overboard, whereas water from the upper part of the bilge is pumped through an oil separator prior to discharge. As illustrated in Figs. 1 and 2, two pumps 1 and 3 initially operate simultaneously, the pump 3 discharging directly overboard and the pump 1 discharging through an oil separator 5. When the water level in the bilge 2 has fallen to such a level that oil might be pumped, a float 4 deenergizes the pump 3 or renders it ineffective by opening an aperture in its suction line. Water is then pumped solely through the separator 5 as shown by the arrows in Fig. 2. A check valve 15 prevents return flow. The water passes through a three layer oil filter 20 of foamed polystyrene whose porosity decreases in the direction of water flow. An air vent valve 7 is opened by a float 17 to avoid undue accumulation of air in the separator. The separator container 18 is transparent. When filter contamination is seen to have advanced to a mark 9, the container with its filter is discarded and replaced. All other separator components are carried by a cover 29 to ease container/cover replacement. The water outlet pipe has a pointed lower end so that it can be pushed through a new imperforate filter. Alternatively, filters may be prefabricated with a central opening for the outlet pipe. Since oil accumulates on the surface of water in the separator, the upper part of the separator may be connected to oil collection bags, Fig. 4 (not shown), into which surface oil is forced and which can be severed from the separator, when they are full. In a modification, Fig. 3 (not shown), the air vent valve is controlled directly by a float rather than via an electric switch. In another modification, Fig. 8 (not shown), the separator has no air vent, and an air separator is provided upstream of the oil separator. In the modification of Fig. 6, a two-stage oil separator is provided. A coarse stage 102 rides on a coarse filter 113 and on the ability of coarse oil particles to separate and form a surface layer 119. A float 127 lies between the oil layer 119 and the water 120 and, when the accumulation of oil has sufficiently depressed the water level, operates a pump 130 to discharge oil into a surrounding container 101. A further float 125 operates an air venting valve 124. The fine separator 103 includes a three layer filter 112. Oil in the container 101 is discharged when its level reaches a detector 117. Any water in the container 101 is discharged at 132. The Fig. 6, arrangement may be modified by omitting the filter 113 from the coarse separator and including another separator operating with a coarse filter. In an alternative form of coarse separator, Figs. 7 and 8 (not shown), water is forced to flow through passages formed by upwardly inclined perforated baffles, water leaving the passages to flow downwardly to an outlet, and oil leaving the passages to flow upwardly to a surface layer. A variety of modular arrangements of oil and air separators may be adopted, Figs. 9-15 (not shown).