The rotary screening machine is a reliable and easy-to-operate piece of equipment used for particle grading in fertilizer production lines. Unlike vibrating screens, which require adjustments to excitation force and amplitude, this machine relies on the smooth rotation of the drum to perform screening; it involves fewer operating parameters, making it easy for workers to master. The screen mesh is the only wear part requiring periodic replacement; it is convenient to install and remove, resulting in low maintenance costs. The equipment supports continuous feeding and discharging, automatically performing grading with minimal manual intervention. In organic and compound fertilizer workshops, the rotary screen is typically positioned after the drying and cooling stages; it clearly separates materials into three grades—qualified granules, fine powder, and oversized lumps—thereby supplying finished products with uniform particle size to the packaging section.

After entering the inclined rotating screen drum through the inlet, the material is lifted to a certain height by the drum’s rotation before rolling down and moving forward under gravity. As the material continuously tumbles and scatters inside the drum, the particles make repeated contact with the screen surface. Particles smaller than the screen apertures pass through into the discharge hopper below, while larger particles roll along the drum to the discharge end. When configured with a multi-layer drum, the material passes sequentially through screen surfaces with varying aperture sizes from the inside out, achieving multi-stage separation. The drum rotation speed is generally low, and the material’s residence time inside the drum can be adjusted by varying the inclination angle and rotation speed.