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.
Reliability is a key factor in the design and manufacture of vibrating feeders. In this paper, a method considering materials force was proposed to optimize the structure of the vibrating feeder. Discrete Element Method (DEM) was used to couple the materials force and the excitation force based on the phase characteristics of the vibrating feeder, and Finite Element Method (FEM) was used to analyze the vibrating feeder structure based on the inertia release method. In order to reduce the stress on the beam of the vibrating feeder, three structural improvement schemes were proposed, which were constructing a statically indeterminate structure, increasing the width of the rib‐stiffened plates on the beam, and increasing the internal spacing of the beam. Then, these three schemes were compared using the FEM. Finally, the response surface method was used to optimize the width of the inner and outer rib‐stiffened plates. The research results showed that when the vibrating feeder moved close to the highest point, the materials force reached the peak. The maximum first principal stress occurred at the middle and both ends of the vibrating feeder beam under the joint action of the excitation force and the materials force. The first principal stress value of the beam was most significantly decreased by increasing the width of the rib‐stiffened plates on the beam of three optimization schemes. The optimal increment of rib‐stiffened plate width was 30 mm with the maximum first principal stress value reduced by 40.12%.