Starch slurry obtained by rasping is pumped into the De-sanding Cyclone unit through fiber pump. Material with some pressure enters into the De-sanding Cyclone unit along tangent direction. Potato slurry in the De-sanding Cyclone unit rotates at high speed. The light starch and potato fiber overflow from the top, sand and other heavy waste discharge from the bottom. Ceramic cyclone tubes following a deposition sand tank which associated recoil water with pressure guarantee the loss of starch from the end of stream mouth. The sands periodically discharged through the two air bags valves.