Study on Efficiency of Solid-Liquid Separator by Vibration Analysis

Tsujiuchi Nobutaka (Doshisha University)

CHALLENGE - The Solid-Liquid Separator is commonly used for sludge disposal in water purifying plant and draining water off from food. The solid-liquid mixture is separated into solid and liquid by using a screen with slits. Using a screen with narrower slit distance allows to separate finer objectives, although the efficiency is negatively affected by solid clogging at slits. The solution is to adopt a vibrating screen induced by a vibration exciter.

SOLUTION The study initially focused on the experimental modal analysis to determine the vibration properties of three different screen types: (600 and 900mm are used for the model and 1200 mm for verification). In the following evaluation test, a solid-liquid mixture (made of acrylic fine particle mixed water) passed through the screen with multiple excitation frequencies in order to evaluate separation efficiency and measure the water draining position. The results showed that the optimal excitation frequency has the vibration shape similar to 1,3 mode for all types.

BENEFITS The material properties related to the 600 and 900 model screen type (poisson’s ratio, longitudinal elastic and shear modulus) were optimized by using modeFRONTIER multi-objective genetic algorithm MOGA-II in order to simultaneously minimize objective function for natural frequency and natural vibration mode. The Pareto front results allow to select the qualified virtual material property solution that satisfies constraint conditions (error of natural frequency ± 5hz and MAC value 0.9).