Screw Sand Washing Zenith screw sand washing machine is mainly used for sand processing, electric pole factory, building work site and concrete dam, various sands classifying and dewatering. Washing: The sand is feeding into the sediment pool from the feeding box, acting by rotating screw blade, the sand is turning and rolling and grinding each other to eliminate impurity and water-air layer around sand to facilitate de-water. The fresh eater rising current from the porous plate carry foreign matter to water surface and overflow the weir plate, to finish washing processing De-watering: The sand with bigger density is sunken down to tub bottom, the screw blade push this sand upwards, when passing through upper tub of proper length above water level, the water is draining into sediment pool from another drainage ditch, the de-watered sand is out from the discharging opening. Classifying: Material classifying is realized by overflowing the non-needed fines, the controlling method is adjusting height of overflowing weir and adjusting speed of screw.