SE370186

1334056 Removing scum from liquid ENVIROTECH CORP 30 Oct 1970 [30 Oct 1969] 51649/70 Heading BID Scum is removed from liquid in a settling or aeration tank by a moving baffle 38 which pushes the scum 47 before it towards a fixed baffle 50, means 54 engaging baffle 38 and causing it to pass beneath baffle 50 leaving the scum upstream of baffle 50, whence it is removed by endless conveyor 58 running along baffle 50. As illustrated baffles 38 and 50 extend radially of a circular tank with a central inlet and peripheral overflow for clean liquid, but the invention is applicable to rectangular tanks. Scum is excluded from the clean liquid overflow by annular baffle (24). In Fig. 3, baffle 38 is pulled along behind a conventional tank floor scraper (Fig. 2, not shown) and biassed upwards by springs 44. Scum 47 is carried down the underside of ramp 54 by baffle 38 and then rises between baffle 50 and another fixed baffle 52 which define channel 48 in which conveyor 58 operates. Rails 56 guide baffle 38 under baffles 52 and 50. In Fig. 4 (not shown) baffle 38 has a float (82) in place of springs 44. In Fig. 5 (not shown) there is only one fixed baffle 50 and guide rails (86).