Screening Mechanism And Equipment Design Of Variable Amplitude Vibrating Screen With Mass Center Offset

In the process of modernization,the demand for machine-made aggregate is increasing.Screening and classification technology is the key link of aggregate quality assurance,which requires high screening efficiency and structural reliability of screening machinery.The ordinary vibrating screen has simple structure and strong applicability,but the screen surface movement form is single,so it can not give full play to the screen performance.The goal of this project is to study a new type of vibrating screen with variable amplitude and mass center deviation.The exciting force of the vibrating screen is shifted from the mass center of the screen box,the motion form of the screen surface is changed,and the screening efficiency of the vibrating screen is improved.Based on the design criteria of the ordinary linear vibrating screen,the influence of the design parameters is analyzed,and the design parameters of the vibrating screen with variable amplitude of mass center deviation are preliminarily determined.Through the analysis of the function and structural strength of each component of the vibrating screen,the structure of each component of the vibrating screen with variable amplitude of mass center deviation is preliminarily designed,and the parameter influence caused by the mass center adjustment device is mainly analyzed.This paper analyzes the vibration characteristics of the shaker with variable amplitude of mass center deviation,constructs the dynamic model of shaker box vibration,analyzes the swing amplitude caused by mass center deviation,and the influence of swing amplitude on the amplitude,phase and throw index of each point of shaker box.The influence of screen installation position on aggregate screening is analyzed,and the quality and installation position of mass center adjusting device are determined by taking the coincidence of screen and vibration mass centroid as an example.Based on the discrete element theory,the screening process of vibrating screen is simulated,and the contrast experiment is set up to verify that the centroid migration method can indeed improve the screening efficiency.Based on response surface analysis and Latin hypercube sampling method,the function expression between the amplitude,frequency,swing amplitude and screening efficiency of vibrating screen is obtained.The influence of each parameter on screening efficiency is analyzed and the parameter value is optimized.After optimization,the screening efficiency of variable amplitude vibrating screen is 15.32%higher than that of ordinary screen.Based on the finite element method,the static analysis of the vibrating screen box is carried out,and the deformation and stress nephogram of the screen box under the maximum load are obtained.The first six natural frequencies and modes are obtained by prestressed modal analysis of the shale shaker with gravity load and elastic constraints.On the basis of modal analysis,the vibration screen is loaded with alternating loads of different frequencies,and the harmonic response analysis is carried out.It is found that the deformation and stress value of the bottom plate and the cross beam of the screen box are too large under the working frequency.The structure of the screen box is adjusted,and its structural strength is obviously strengthened.The research of this subject puts forward a new type of vibrating screen with variable amplitude of mass center offset,which can improve the screening efficiency of vibrating screen under the condition of ensuring productivity and structural strength.It provides a new scheme and theoretical basis for the design and selection of high-efficiency vibrating screen,and promotes the development of related industries.