Principle ofspiral sand washing machine is, size or proportion of different solid particlesettling velocity in the liquid is different, fine mineral particles suspendedin water or overflow, coarse particles sink to the bottom. The spiral dischargedfrom the up, is a kind of classification equipment for mechanical grading. Milldischarging through the filter, coarse material is screwed into the mill inletusing on-chip spiral vane, the fine filter out from the overflow pipe. The baseof the machine adopts a channel, the body adopts welded steel plate.