Kinematics characteristics of the flip-flow screen with a crankshaft-link structure and screening analysis for moist coal

Abstract

The flip-flow screen is an effective solution for the screening of high-water and fine materials. In this study, a flip-flow screen with crankshaft-link structure (FFSCLS) was proposed, and kinematic model governing the vibration of the screen are also presented. Kinematics characteristics of the FFSCLS was obtained using vibration experiments and analysis unit, and the classification performance under different operational conditions were studied by the screening experiments and analysis system to reveal the mechanism of deep screening about moist fine coal. The results show that the vibration experiment result of the flip-flow screen can be fully described by the kinematic model with the maximum deviation was within 6.84%. The moving directions of the outer and the inner screen boxes are opposite and the phase difference is 180° along X -axis. The trajectories of the outer and inner screen boxes are approximate ellipse. The acceleration amplitude along X -axis of the inner and outer screen boxes reached 9.8 and 16.2 m∙s−2 with rotational speed of the driving motor n of 575 r∙min−1. The rotational speed n showed significant influences on the kinematics and screening efficiency of the FFSCLS. The vibration of the outer screen box increases rapidly while that of the inner screen box increases slowly with the increase of n. in addition, with the increase of the rotational speed of driving motor n, the screening efficiency first increased and then decreased. With the increase of feeding rate Q, the screening efficiency gradually decreased. It was found that the screening efficiency was higher than 85.82% when n = 575 r∙min−1, and Q ≤ 3 kg∙s−1. This indicated that the FFSCLS has excellent performance for moist coal screening.