Properties of technological factors on screening performance of coal in an equal-thickness screen with variable amplitude

[Display omitted] •A VAETS was proposed for classification of coal.•Effects of technological factors on screening performance of VAETS were studied.•Method of multistage sampling was used to analyze sectional screening efficiency.•Screening efficiency was used to evaluate the screening performance of VAETS. Screening has been widely used for the classification of particulate materials. Equal-thickness screen, which is characterized by large capacity and high efficiency, has been extensively applied in coal processing in recent years. In this paper, the method of multistage sampling and multilayer screening was used to analyze the particle size of screening products, the effects of screen surface inclination, unbalanced exciting force, excitation beam span and feed rate on the screening efficiency and partition size of coal in an equal-thickness screen with variable amplitude (VAETS) were investigated. The results showed that the sectional efficiency of the screen surface decreased along the material flow. With an increase in the screen surface length, partition size and screening efficiency gradually increased, and tended to attain a constant value. Screen surface inclination had a significant effect on partition size and screening efficiency, the partition size decreased, while the screening efficiency first increased and then decreased with an increase in the screen surface inclination. Unbalanced exciting force, excitation beam span and feed rate have a weaker impact on the partition size and screening efficiency of the VAETS. With an increase in the screen surface inclination, unbalanced exciting force, excitation beam span and feed rate, the screening efficiency first increases and then decreases. When screen surface inclination, unbalanced excitation coefficient, excitation beam span and feed rate have values of 15°, 1.228, 540mm and 3.60t/h respectively, the screening efficiency reaches its maximum value of 94.37%, while the corresponding total misplaced material is 2.92%.