Rebound plate design for flip-flow screen and effects on screening process of material group

Abstract

With the 30-50g ejection acceleration of screen panels, the flip-flow screen provides an effective solution for fine coal screening. However, the high ejection acceleration prolongs material particles residence time in the air, which leads to insufficient contacts between particles and screen panels, and finally resulting in the aggravation of particles mismatches. To decrease the mismatch rate, the idea of introducing secondary collisions for particles is proposed, thus, the rebound plate is designed for the flip-flow screen. Firstly, the co-simulation of the screening process is built to investigate the height distributions of material group particles. Then, the installation structure and height range of the rebound plate is determined according to particles motion laws. Moreover, the motion trajectory comparison of a single particle on flip-flow screens with and without the rebound plate is performed to evaluate effects of secondary collisions. Finally, influences of rebound plate installation heights on material group motions, particle-screen panel contacts and screening performances are studied. Results indicate that the installation of the rebound plate increases contact probabilities and penetrate probabilities of material group particles. When the installation height is 120-150 mm, the screening efficiency can be significantly improved at less expenses of the productivity loss.