Surface skimmer means for settling tank

Claim 1

In a circular settling tank for separating solids from a solids-liquid suspension feed input, a feedwell arranged at the center of the tank for receiving said feed input, an overflow launder extending about the upper outer periphery of the tank for discharging supernatant liquid separated from solids settled at the tank bottom, a second outlet means at the bottom of the tank for said settled solids, a rotary rake structure having spaced rake arms effective to move said solids over said tank bottom to said second outlet means, a circular baffle about the inner upper periphery of said tank spaced from said launder, and skimmer means provided between said feedwell and baffle for sweeping floating materials from the surface of the supernatant liquid to a collector mounted at said baffle at the periphery of said tank, said skimmer means comprising: a. an elongated wiper arm carried by at least one rake arm, and extending radially across the tank, said arm having one end engaging said baffle and the other end engaging the outer wall surface of said feedwell in operative sweeping position, b. spring means maintaining said ends of said wiper arm in engaged operative position with said feedwell and said baffle, and c. cam actuated means carried by said wiper arm and operable for moving said wiper arm about a pivot to disengage said other end of said wiper arm from said feedwell and move said wiper arm into engagement with said peripheral baffle to sweep floating material into said collector through an elongated opening therein.