In-depth analysis of the dynamic features and screening performance of high-elasticity projection vibrating screen

Abstract

With the increasingly stringent requirements of industrial production on the particle size of the material, dry depth screening technology came into being. In order to further realize effective separation and efficient classification of fine-grained coal, a new high-elasticity screen surface equipped with additional striking shaft was designed in this paper. The performance of vibrating screen was explored by combining theoretical modeling, vibration testing, numerical simulation, and screening tests. The dynamical model of the vibrating screen was established using concentrated mass method, showing that the equipment underwent a linear motion of low vibration intensity perpendicular to the screen surface. The trajectories of the machine and the striking shaft under different excitation parameters obtained from the vibration test showed regular straight lines, and the relative errors between the theoretical and actual displacements were controlled within 3 %. The dynamics of an elastic screen surface of a four-sided simply supported shaft was built, and expression for its transient steady-state response to an impact was derived. Vibration tests showed that the spatial trajectory of the screen surface was relatively chaotic, but the maximum acceleration could be as high as 304.61 m/s², and the displacement reached 30.31 mm, which promoted the movement of particles with high ejection intensity. In contrast, the elastic screen surface under simulation exhibited hysteresis and nonlinearity, and the excitation parameters significantly affected the contact stresses and forces, with significant peaks in stresses and contact forces at L = 7.5 cm and f = 11.4 Hz, and the largest displacements and penetrations generated at point P1. Additionally, 3 mm classification tests were carried out for sticky-wet materials with different excitation forces, frequencies and shaft distance to optimize the processing parameters, and it was found that when F = 19 kN, f = 12.0 Hz, Δl = −0.5 and k_l = 0.938, the screening efficiency was up to 92.45 % and the total mismatched content was only 4.78 %. The paper discussed the relationship between additional striking shafts, elastic screen surfaces, and classification effects, aiming to provide theoretical and technical guidance for elastic screening equipment.