The working flow of the sand washer: the sand and gravel are sent to the silo by the loader, and then sent to the roller screen through the conveyor belt for screening; The coarse sand slides out of the chute after screening, and the fine sand enters the wheel sand washer, which is driven by the impeller to roll and grind each other, so as to remove impurities covering the sand surface and destroy the water vapor layer covering the sand particles, which is beneficial to dehydration; At the same time, water is added to form a strong water flow, which takes away impurities and foreign bodies with small specific gravity in time and discharges them from the overflow port; Clean sand and gravel are poured into the discharge rod from the rotating impeller and piled up to complete the sand and gravel cleaning function.