Patent ID: 8580123

Claim:
A skimmer comprising: a frame for supporting a drive sprocket and for supporting a drum; a conveyor driven around the drum by the drive sprocket, the conveyor defining a downwardly moving upper flight and an upwardly moving lower flight; a trough disposed below a portion of the lower flight, the trough extending from the drum to a discharge opening; a pusher mechanism disposed at the discharge opening to force bitumen or heavy oil from the conveyor into the discharge opening; a shear plate disposed at the discharge opening, wherein the shear plate has a knife-edge for cutting away bitumen or heavy oil adhering to the conveyor; and an automatic elevation control system for generating a control signal when sensing an elevation of the conveyor and for automatically controlling the elevation of the skimmer based on the control signal by controlling hydraulic cylinders to cause wheels of the skimmer to roll over guide rails to raise or lower the skimmer.