Screening efficiency of a small multi-layer circular vibrating granulometer

HE Zhaohui; SHI Yunlai; WANG Junhan; GUO Jiaxin

doi:10.13732/j.issn.1008-5548.2025.02.010

Abstract：Objective The screening efficiency of a vibrating particle size analyzer is a key indicator of its effectiveness in particle size sepa-ration.However,there has been limited research on the screening efficiency of small multi-layer circular vibrating screen par-ticle size analyzers under different vibration parameters.This study investigates the impact of vibration frequency,amplitude,and other factors on the screening efficiency of quartz sand and river sand particles,aiming to identify the optimal vibration parameters that maximize particle screening efficiency and improve the energy utilization of the device. Methods A small multi-layer circular vibrating particle size analyzer was designed,using mechanical vibrations to separate par-ticles through six layers of standard circular sieves.The core functional module of the analyzer was the vibrating screening device,consisting of a voice coil motor as the vibration source,springs,a fixed base plate,and a top plate forming a complete vibration system.The voice coil motor offered the advantages such as fast response and convenient control,allowing parameter adjustments of vibration frequency and excitation force through a device drive controller.Rocky DEM simulation software was employed to simulate the screening process of quartz sand and river sand particles.Parameters such as vibration amplitude and frequency were adjusted in the motion settings of the software,while material properties of each structural part of the device and contact parameters between particles and the sieve,as well as between particles themselves,were configured in the software material database.The screening efficiency of particles on the first and sixth layers of the sieve under various amplitudes and vibration frequencies over a certain period was calculated,producing efficiency curves as a function of these parameters.Experi-ments were conducted by measuring the vibration amplitude of the voice coil motor under different excitation forces and frequen-cies using a laser vibrometer.Screening efficiency tests of quartz sand and river sand particles were then performed within the optimal frequency and amplitude ranges obtained from the simulation. Results and Discussion The Rocky DEM simulation results showed that the screening efficiency of quartz sand and river sand particles exhibited similar trends in terms of vibration amplitude and frequency.The highest efficiency was achieved when the vibration frequency was within 75-105 Hz and the amplitude was between 0.1-0.2 mm.Experimental results further validated these findings,showing that when the excitation force ranged between 70-90 N,the amplitude of the voice coil motor was 0.08-0.23 mm at a vibration frequency of 75-105 Hz,aligning closely with the optimal parameters from the simulation.Within these optimal parameters,the screening device achieved high efficiency,with screening efficiency exceeding 90％for both types of particles when the screening duration was set to 5 minutes and the excitation force was set to 90 N,meeting the qualification stan-dards for particle size analyzers using mechanical screening methods. Conclusion Using a voice coil motor with simple and convenient adjustment of vibration frequency and excitation force as the excitation source,the study examines the screening efficiency of a small multi-layer circular vibrating screening device on sand river and quartz particles under various vibration parameters.The results fill a research gap regarding the screening efficiency of such devices.Operating within the optimal screening parameters derived from the simulation effectively reduces screening time and enhances the screening efficiency of the vibrating particle size analyzer,thereby preventing energy waste due to low screen-ing efficiency of the device.