Screening device used for flour production and used before grinding

The invention discloses a screening device used for flour production and used before grinding. The screening device comprises a feeding area and a screening area, wherein the feeding area comprises afeeding box; the screening area comprises a screening box; a conveying belt feeding mechanism is arranged at the joint of the screening box and the feeding box; the included angle between the conveying belt feeding mechanism and the bottom of the screening box is 10-30 degrees; a boundary plate is arranged at the position, positioned on the right side of the conveying belt feeding mechanism, of the inner surface of the screening box; a discharging port is formed in the position, positioned between the boundary plate and the right side of the screening box, of the bottom of the screening box; and the discharging port is connected with a hopper of a grinding device through a connecting pipe. According to the screening device, materials are poured into a material reducing hopper and fall intothe conveying belt feedin