Continuous flow classification and specific gravity separation apparatus

Continuous flow apparatus for classification and specific gravity separation of relatively fine, heavy sands from gravel and dirt aggregate comprising;

• an elongated channel structure having spaced, opposite walls, spaced upstream and downstream ends, and a bottom wall;
• a top plate member spaced from said bottom wall extending laterally between said side walls and longitudinally substantially between said ends, said top plate member having top and bottom surfaces with said bottom surface defining a longitudinally extending cavity with said side and bottom walls, said side walls having portions upstanding from said top surface of said top plate member and defining therewith a flume extending between said ends, said top plate member having at least a portion thereof extending longitudinally toward said downstream end with a plurality of closely-spaced apertures formed therethrough communicating with said cavity;
• said structure having a back wall extending from said bottom wall to said top plate member and between said side walls at said upstream end;
• said flume being adapted for the introduction of a flow of water bearing said aggregate adjacent said upstream end for flow over said top surface of said top plate member toward said downstream end whereby the relatively smaller, heavier material forming a part of said aggregate falls through said apertures into said cavity along with some water;
• a longitudinally extending table in said cavity spaced below said top plate member and inclined downwardly from adjacent said upstream end toward said downstream end, said table having upstream and downstream ends, said table having side edges respectively adjacent said side walls;
• first means for selectively adjusting the angle of inclination of said table;
• said table having a trough formed therein extending longitudinally between said table ends intermediate said side edges and respectively defining said portions of said table therewith, said trough having a bottom, said table including an extension portion at said downstream end for discharging tailings from said downstream end, said extension portion extending generally from said trough bottom and having an opening therein adjacent said downstream table end communicating with a sump portion of said cavity disposed below said extension portion for discharging said heavy sands thereto;
• weir means for diverting flow of a selected heavier portion of the sands at the bottom of said trough through said opening into said cavity sump portion while permitting flow of the remaining lighter portion of said sands over said weir means onto said extension portion;
• second means for selectively adjusting said weir means thereby to select said heavier sand portion;
• longitudinally extending baffle means over said trough for diverting material and water falling through said apertures onto said table side portions;
• riffle means on each of said table side portions under said apertures for receiving said material and water falling through said apertures and separating the heavier material therefrom, said riffle means respectively extending laterally from said side table edges to said trough and being respectively inclined downstream from said side table edges toward said trough for carrying the heavier sands to said trough;
• third means for selectively adjusting the angle of inclination of said riffle means;
• means for selectively introducing an additional flow of water into said cavity adjacent said upstream table end and between said table and said top plate member for flow over said riffle means and in said trough toward said downstream table end;
• and means for removing the separated heavier sands from said cavity sump portion.