Sewage filtering device based on rotational flow sand setting principle

The utility model provides a sewage filtering device based on a rotational flow sand setting principle, and belongs to the technical field of sewage treatment. A water inlet and a water outlet are formed in the upper portion and the middle of the sand setting box respectively, a rotating shaft is rotationally connected to the center of the inner top of the sand setting box and vertically penetrates through the top of the sand setting box, a driving structure is connected to the upper end of the rotating shaft, and the lower end of the rotating shaft extends into the sand setting box. The impeller rotates to form a rotating fluid force field in the sand setting box, a sewage guide assembly capable of enabling sewage to obliquely flow into the rotating fluid force field is arranged below the water inlet, a sand setting flow channel with a conical inner cavity is formed in the bottom of the sand setting box, a sand accumulation box is arranged below the sand setting flow channel, a sand outlet flow channel is fo