The improved classifier adds a sand return automatic lifting device at the sand return end of the classifier, which lifts the ore discharged at the bottom of the groove to an appropriate position on the wall of the classifier, so as to save 1-1.5 degrees of electricity per ton of ore after the mill eliminates the big spoon head, while avoiding the frequent maintenance of the spoon sand and reducing the wear of the ball mill gear.

The spiral classifier is composed of U-shaped sink, spiral, transmission device, lifting mechanism, supporting bearing and other parts. The overflow weir of the high weir classifier is higher than the lower end bearing, but lower than the upper edge of the lower end spiral. The U-shaped groove of the spiral classifier is equipped with a longitudinal long axis with spiral blades, and the lower end is provided with an overflow weir. The transmission device is installed at the upper end of the groove body, the upper end of the spiral spindle is supported in the bearing of the transmission frame, and the lower end bearing is installed at the bottom of the lifting mechanism. The lifting mechanism can make the lower end of the spiral lift to adjust the distance between the spiral and the bottom of the groove and adjust the size of the spiral load. At the same time, the screw is lifted when stopping to prevent the sand settling and burying pressure screw, affecting the next start.

The spiral classifier is based on the principle that the size of solid particles is different, the specific gravity is different, and therefore the settling speed in the liquid is different, the fine ore particles float in the water into overflow, and the coarse ore particles sink at the bottom of the tank. A grading device for mechanical classification by pushing the screw to the upper part of the discharge, which can grade the ground powder in the mill to filter, and then screw the coarse material into the feed port of the mill using the spiral plate, and discharge the filtered fine material from the overflow pipe. The machine base is made of channel steel, and the body is welded with steel plate. The inlet head and shaft head of the spiral shaft are made of cast iron sleeves, which are wear-resistant and durable, and the lifting device is divided into two kinds: electric and manual.