Hindered-settling fluid classifier

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;
• an overflow passage communicating with the open upper end of said rising current column for directing the liquid medium flowing outwardly from said sink fraction chamber into said float fraction chamber;
• a first screw conveyor for removing an aggregate float fraction entrained in the liquid medium and collecting inside the float fraction chamber;
• and
• a second screw conveyor for removing an aggregate sink fraction collecting inside the sink fraction chamber.

A method for classifying material aggregate in a liquid medium, said method comprising:

• depositing dry material aggregate into a classifier tank of a hindered-settling fluid classifier, the classifier tank comprising a sink fraction chamber and a float fraction chamber;
• feeding the dry material aggregate through a deposit chute and into a rising current column vertically mounted within the sink fraction chamber;
• generating an upwardly whirling flow of liquid medium inside the rising current column, the liquid medium comprising an entrained fraction of material aggregate;
• directing the liquid medium exiting the rising current column into the float fraction chamber;
• removing from the classifier tank an aggregate float fraction entrained in the liquid medium and collecting in the float fraction chamber;
• and
• removing from the classifier tank an aggregate sink fraction collecting in the sink fraction chamber.