Patent ID: 7131538

Claim:
A material classifier for washing, classifying and dewatering a liquid-solid mixture containing solid material, comprising: a tank defining a reservoir having a first end at which the liquid-solid mixture is received and a second end from which liquid from the liquid-solid mixture is discharged, the tank including an angled side wall located between the first end and the second end; a first wheel mounted at least partially within the tank adjacent the side wall to rotate about a first wheel axis that is tilted at an angle relative to a horizontal reference and that is substantially perpendicular to the side wall, the first wheel having a plurality of spaced apart radially extending scoops about a periphery thereof for scooping up a first grade of solid material from within the tank and subsequently discharging the scooped solid material from the side wall to outside of the tank during rotation of the first wheel; and a second wheel mounted at least partially within the tank adjacent the side wall and further from the first end than the first wheel to rotate about a second wheel axis that is tilted at an angle relative to a horizontal reference and that is substantially perpendicular to the side wall, the second wheel having a plurality of spaced apart radially extending scoops about a periphery thereof for scooping up a second grade of solid material from within the tank and subsequently discharging the scooped solid material from the sidewall to outside of the tank during rotation of the second wheel.