Vibrating flip-flow screens have been widely used in the mineral processing industry. As the key components, flip-flow screen panels strongly affect the dynamics of vibrating flip-flow screens. However, there is no systematic research into this problem. In this study, the dynamic characteristics of flip-flow screen panel are identified by the finite element analysis. Furthermore, a nonlinear coupling dynamic model of vibrating flip-flow screens that considers the effects of flip-flow screen panels is proposed, and the analytical and numerical solutions of its governing equation are deduced via the equivalent linearization method and the time marching method. Also, experimental results show that the proposed model describes the movements of vibrating flip-flow screens more accurately than the classical mechanical model which does not consider flip-flow screen panels. Finally, the effects of the screen panel’s parameters, such as the slack length and the stiffness, on the dynamics of vibrating flip-flow screens are investigated.

Moisture content has an important influence on the stratification and screening of materials on the surface of screens, and materials with different external moisture concentrations present different screening characteristics. A vibrating flip-flow screen (VFFS) is a two-body vibration system with a high-vibrating-strength screen surface developed based on a circular vibrating screen (CVS), which offers significant advantages in terms of handling sticky fine particles. To better understand the difference in screening performance between a VFFS and CVS under different external moisture concentrations, it is necessary to conduct a comparative study on the distribution characteristics of materials on the screen’s surface. In this paper, a CVS dynamic model considering the stiffness force and position of the damping spring is proposed, and the influence of different arrangements of damping springs on the amplitude and angular displacement of the screen is analyzed. Under different external moisture concentrations, the screening percentages of the 3–1 mm sized fractions in sections I–IV of a VFFS and a CVS are greater than those of 1–0 mm sized fractions. The screening efficiencies of CVSs and VFFSs are 92.54% and 92.19%, respectively, at an external moisture content of 4.30%, so the screening effect of a low-vibration-intensity screen surface is better in the case of better material stratification. When the external moisture content of the material was increased from 4.30% to 8.19%, the screening efficiency of the VFFS and the CVS decreased by 33.85% and 41.32%, respectively. The screening efficiency of the CVS is more sensitive to the external moisture content of a material.

This study systematically investigates the impact of pre-stretching amount (PSA) on the acceleration, motion status, and screening efficiency of the Flip-flow screen plate (FFSP). Initially, a nonlinear spring-multi-body model of the FFSP is established. Subsequently, the acceleration signals at the midpoint of the FFSP under various PSAs are measured and analyzed. The nonlinear stiffness coefficient of FFSP along the vertical direction is then determined and it is found that simplifying the nonlinear spring-multi-body system to a nonlinear spring-tri-body system under the experimental conditions can maintain the calculation error of FFSP’s acceleration within 30%. Phase and Poincaré mapping diagrams of the FFSP under different PSAs are subsequently created to illustrate the impact of PSA on the motion status of the FFSP. Finally, screening experiments are performed to study the optimal PSA for a kind of bituminous coal from Shanxi province.