Patent ID: 7891496

Claim:
A hindered-settling fluid classifier adapted for processing material aggregate in a liquid medium, said fluid classifier comprising: a classifier tank defined by walls designed for holding the liquid medium, and comprising a sink fraction chamber and a float fraction chamber, and a fluid inlet and a fluid outlet; an elongated rising current column vertically mounted within said sink fraction chamber, and adapted for extending below a surface of the liquid medium held therein, said rising current column having open upper and lower ends, and defining an aggregate entry between its upper and lower ends for receiving material aggregate into said classifier tank, whereby a portion of the material aggregate entering said rising current column is carried upwardly in an upwardly directed flow of liquid medium within said rising current column; a float fraction reservoir above said sink fraction chamber, and communicating with the open upper end of said rising current column; an overflow passage communicating with said float fraction reservoir and adapted for directing the liquid medium outwardly from said reservoir and into said float fraction chamber; means for removing an aggregate float fraction entrained in the liquid medium and collecting inside the float fraction chamber; and means for removing an aggregate sink fraction collecting inside the sink fraction chamber.