Research on the mechanism of equal-thickness screening process formation of banana-type vibrating screens based on the signal analysis of the wavelet packet energy spectrum

Abstract

ABSTRACT Banana-type vibrating screen has been widely used in classification operations in coal cleaning and mining fields due to good screening performance and large processing capacity. In this work, a new analytical method was introduced to clarify the mechanism of equal-thickness formation of banana-type vibrating screens. The vibration characteristics of the collision between the screen surface and the particles were analyzed using the wavelet packet frequency and the energy spectra. The main frequency band of the collision at the infeed and outfeed ends was the 2nd frequency band (low-frequency band). The corresponding amplitude and energy percentage value of the screen surface at the infeed end were 0.12 mm and 4.3%, respectively, which were higher than those at the outfeed end. The spectral amplitude and the energy percentage value had “high-in and low-out” characteristics which verified the mechanisms of thin-layer penetration and equal-thickness formation of banana-type vibrating screens. This work contributes to the theory of equal-thickness screenings and provides new research ideas and technical support for designing vibrating screens.