Deflection of screen surface and spatial deformation law of screen apertures during 1 mm elastic screening

Under the action of water and clay minerals, the process of wet material screening has some problems such as strong adhesion between fine particles, significant agglomeration effect, difficulty in particle separation and layering, and severe clogging on the screen surface, leading to difficulties in material sieving and poor screening performance, which can severely restrict the large-scale upgrading and processing of coal. To overcome the problems above, combining vibration testing and multi-flexible body dynamics simulation methods, the kinematic characteristics of elastic screen surface and 1 mm elastic screening test were carried out. The response characteristics of the deflection deformation of elastic screen surface to the excitation parameters was analyzed under harmonic vibration, and the laws of elastic screen surface deflection deformation and screen aperture spatial deformation were revealed. The deflection of the screen surface and the spatial morphology of holes were reconstructed. The influence of excitation parameters on the screening effect of 1 mm elastic screening was studied through screening experiments, and the optimal excitation parameters were determined. In addition, the 1 mm screening performance of rigid and elastic screen surfaces on the materials with different moisture contents were compared and analyzed. The results showed that the effect of harmonic vibration promoted the large deformation and bending motion of the elastic screen surface. And the elastic screen surface could generate greater vibration acceleration and deformation compared to the screen body. During the vibration process of the elastic screen surface, the deflection deformation characteristics of screen surface could effectively overcome the problem of screening blind zones in the edge area and ensure the effective opening area of screen surface. The three-dimensional curved screen holes significantly increased the probability of fine particles through screen. The screening efficiency was up to 80.15% when the excitation force, excitation frequency and vibration direction angle were 8.5 kN, 14.08 Hz, and 50°, respectively. As the external moisture content of the material increased, the high vibration intensity of the elastic screen surface promoted the depolymerization of agglomerated fine-grained particles, strengthening the looseness and permeability of material and its screening performance was significantly better than that of the rigid screen surface, which could meet the technical needs of 1 mm dry screening.