Multi-frequency Vibration Synchronization and Stability of the Nonlinear Screening System

Abstract

For vibrating screen machinery, the granular block material can be quickly loosed and fully layered when entering the screening equipment if it is placed an exciting system with low frequency and large amplitude at the feeding end. A high frequency with small amplitude exciter is set near the discharging end. It can make the material appear high-frequency vibration and reduce the phenomenon more effectively that the granular material blocks the screen hole. Because of this, taking the elliptical vibrating screen system as our research object, the concept of compound nonlinear screening trajectories is proposed from the two times frequency vibrating synchronization system driven by three exciters. Firstly, the differential motion equation of the system is obtained by establishing the Laplace equations of the system. Then, by introducing small parameters and dimensionless time parameters, the first-order differential motion equations of the driving motor of the exciters are obtained, the second approximate motion equation of the system is obtained by applying the principle of the average method. Based on this, the criterion for the system to achieve the multi-frequency vibration synchronization state and the phase difference relations among the exciters at steady-state are drawn out by taking the two times frequency vibration synchronization as an example. Meanwhile, the stability criterion of the vibration synchronization state of the system is analyzed. Besides, the functional relation that the location and the rotational direction of the exciters influence on the phase difference of the exciters are given out. Finally, the correctness of the theoretical research is verified by experimental research; the prospect of engineering application of the system is discussed.

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

“…Dry separation techniques have been used in various mineral beneficiation processes, and screening based on the particle shape and size plays an important role in the large-scale separation of minerals [1]- [5]. However, conventional screening equipment (linear vibrating or circular vibrating screens) frequently encounters the problem of rapid blockage of screen apertures, which reduces the screening efficiency and increases the labor intensity of workers [6]- [8]. The main and floating screen frames of vibrating flip-flow screens (VFFSs) generate relative movement along the screen surface under the exciter's simple harmonic excitation [9]- [11].…”

Bidirectional Controlled Multiple Synchronization of Unbalanced Rotors and Its Experimental Evaluation

“…Based on this theory, the synchronization machinery of traditional rigid transmission (e.g., gear transmission) and flexible transmission (e.g., chain or belt transmission) are gradually reduced, replaced by vibration synchronization equipment driven by two or more exciters. They enable the vibrating system to achieve linear motion trajectory, elliptical motion trajectory and other kinds of nonlinear trajectories through vibrating synchronization (Li and Chen, 2019). The application of this theory made the work of synchronous machines extremely simple, making the maintenance easy and convenient and significantly improving the reliability of these machines.…”

“…In (Li and Chen, 2019), Li and Chen analyzed the principle of operation of an elliptical vibration screening system driven by two motors and suggested adding a high frequency, low amplitude exciter at the end of the discharge, reducing screen clogging and separating the granular particles of the viscous block quickly and efficiently. Steady-state phase relationships for double frequency synchronization of vibration are ob-tained and a functional relationship is given, according to which the location and direction of rotation of the exciters affect the phase difference between the actuators.…”

“…Steady-state phase relationships for double frequency synchronization of vibration are ob-tained and a functional relationship is given, according to which the location and direction of rotation of the exciters affect the phase difference between the actuators. Experimental results from (Li and Chen, 2019) have shown that synchronization of multi-frequency oscillations with three exciters can be achieved. The phenomenon of vibration synchronization of a two-mass oscillatory system driven by two actuators was studied in (Liu et al, 2020).…”

Study on Optimization Parameters of Solid-Liquid Separator

“…The screen box and the screen are produced in the form of a circle, a straight line, an ellipse, etc. by the exciting force of a motor [1]. Under the action of vibration, the solid phase on the screen is transported along the screen surface from the feed port to the outlet.…”