A Numerical Study of Separation Performance of Vibrating Flip-Flow Screens for Cohesive Particles

Abstract

Vibrating flip-flow screens (VFFS) are widely used to separate high-viscosity and fine materials. The most remarkable characteristic is that the vibration intensity of the screen frame is only 2–3 g (g represents the gravitational acceleration), while the vibration intensity of the screen surface can reach 30–50 g. This effectively solves the problem of the blocking screen aperture in the screening process of moist particles. In this paper, the approximate state of motion of the sieve mat is realized by setting the discrete rigid motion at multiple points on the elastic sieve mat of the VFFS. The effects of surface energy levels between particles separated via screening performance were compared and analyzed. The results show that the flow characteristics of particles have a great influence on the separation performance. For 8 mm particle screening, the particle’s velocity dominates its movement and screening behavior in the range of 0–8 J/m2 surface energy. In the feeding end region (Section 1 and Section 2), with the increase in the surface energy, the particle’s velocity decreases, and the contact time between the particles and the screen surface increases, and so the passage increases. When the surface energy level continues to increase, the particles agglomerate together due to the effect of the cohesive force, and the effect of the particle’s agglomeration is greater than the particle velocity. Due to the agglomeration of particles, the difficulty of particles passing through the screen increases, and the yields of various size fractions in the feeding end decrease to some extent. In the transporting process, the agglomerated particles need to travel a certain distance before depolymerization, and the stronger the adhesive force between particles, the larger the depolymerization distance. Therefore, for the case of higher surface energy, the screening percentage near the discharging end (Section 3 and Section 4) is greater. The above research is helpful to better understand and optimize the screening process of VFFS.

Effect of Screen-Panel Tensile Length and Material Characteristics on Screening Performance of Flip-Flow Vibrating Screens for Dry-Screening Fine, Low-Grade Bituminous Coal

“…After drying in an oven, subsequent screening using a test sieve, and weighing with an electronic balance, the productivities of the different size fractions at various time intervals can be determined. Additionally, key metrics such as yield of undersized product, screening efficiency, misplaced material, and the distribution rate of each size fraction over different time durations can be assessed [17,24]. Three parallel tests are conducted for each experiment.…”

“…Chen et al simplified the vibration of a flip-flow screen panel into a string model and obtained numerical solutions based on the Hamilton principle [23]. Yu et al divided a flip-flow screen panel into multiple rigid bodies and realized the approximate motion of the screen panel [24]. Peng et al investigated the effect of the initial stretch on the kinematic characteristics of a flip-flow screen panel via an experimental prototype [25].…”

Synchronization and vibration absorption analysis of a dual-body vibrating screen driven by multiple motors with double-frequency actuation

“…As a separation equipment with excellent performance, vibrating screen is mainly employed in the fields of material dehydration, classification and liquid filtration, [1][2][3] especially for the separation of drilling fluid and cuttings in the petroleum industry. For vibrating machinery, many studies focus on its synchronization phenomenon.…”

Nonlinear Model of Vibrating Flip-Flow Screens That Considers the Effects of Screen Panels

“…For example, Chen et al [31] investigated the vibration characteristics of the screen panel of the LIWELL flip-flow screen based on the string vibration model and the Hamilton principle. Other methods were based on DEM and FEM to investigate the motion and stresses of FFSP followed by the screening performance when the VFFS was operating [20], [32]. Wu et al [33] proposed an approximate flexible method of discretizing FFSP into several rigid screen bars and developed a joint simulation between the materials and FFSP using multibody dynamics.…”