PURPOSE: To prevent the wear of a base plate, and to lengthen the life of a conveyor, by a mechanism wherein L-shaped plate bodies are mounted to levers, which are installed to an endless, rotary body at proper intervals and can freely be rotated, and settled sand is scraped out by means of the plate bodies and carried.

CONSTITUTION: Plate bodies 16 scrap up settled sand because the plate bodies 16 move by the revolution of an endless, rotary body 11. The plate bodies 16 scraping up and scraping out the sand upward shift on a slant base plate 18 while their attitudes are changed so as to slowly bend forward by means of guide rails 20, the openings of the plate bodies 16 are downward directed at an upper location of a carrying-out port 23, and sand drops to a lower hopper from the carrying-out port 23. Since the plate bodies 16 slowly bend forward when they move on the inclined portion, water dipped out together with sand flows out from the lower ends of the openings of the plate bodies 16 and returns to a sedimentation basin.