Parameter optimization and spatio-temporal distribution of material for variable trajectory combined equal-thickness screen

Abstract

Vibrating screen is important screening equipment used extensively in coal separation and utilization at the global scale. Traditional vibrating screen usually adopts a single vibration mode, which leads to poor screening effect. In this study, the equal-thickness screening theory was applied to the combined vibrating screen, and non-uniform frequency operation of the vibrating screen was achieved. The concept of combined excitation parameter was introduced, which presented additional adjustable parameters for the screen. These made it easier for material layer on the screen to achieve equal-thickness. Subsequently, single-factor experiments were conducted for systematic exploration of the impact of various parameters on the screening efficiency. By regulating the excitation force and frequency of the four excitation motors of the variable-trajectory combined screen, the study aims to regulate the motion speed of material groups, the distribution of materials under the screen, and the thickness distribution of the material layer on the screen. The result showed that when D = 2/19, f1&f2 = 15.00 & 11.37 Hz, respectively, k = 1.2, equal-thickness screening was realized, and the screening efficiency η was 96.32%, which is 3.35% higher than those under the optimal conditions with equal amplitude and equal vibration frequency.