Study On Optimization Of Process Parameters And Screening Mechanism Of Three-layer Circular Vibrating Screen Based On Building Materials

The development of the construction industry inevitably generates a large amount of construction waste.Utilizing technologies such as crushing and screening to recycle construction waste and apply it to fields such as roadbed and concrete can effectively solve the problems of environmental pollution and shortage of natural aggregate resources.The main component of construction waste after crushing is the crushed stone bound with concrete,which has a large particle size range and needs to be further classified to meet different usage needs.The common screening equipment is a singlelayer sieve,which requires multiple equipment sieves to fully classify.This article uses a three-layer sieve to achieve one-time classification according to engineering needs,and uses the discrete element method to study the screening mechanism of the threelayer sieve.Firstly,this article conducts feasibility analysis of EDEM simulation through three-layer prototype experiments.Then,the entire screening process is simulated using EDEM software to explore the effects of different factors on sieve distribution,material flow speed,material layer thickness,and screening efficiency.Finally,the parameter optimization scheme with the highest screening efficiency is obtained.The specific research is as follows:Use a testing system to calibrate the working parameters of the three-layer circular vibrating screen under no-load conditions and prepare for the test.Based on the post processing module of EDEM software,continuously optimize the simulation model to make it more accurate.Design an experimental plan using the Taguchi orthogonal method,conduct screening experiments and discrete element simulations on a threelayer circular vibrating screen,compare and analyze,and verify the feasibility of using EDEM software for three-layer screens.Propose a multi-layer and multi-stage analysis method to analyze the influence of process parameters on the sieve distribution of material groups on each layer of sieve surface,and obtain the response degree of each region;Clarify the sieving patterns of materials with different particle sizes on each layer and area of the sieve,and reveal the strengthening classification mechanism of the three-layer sieve.Quantify the impact of various parameters on the material flow velocity of each layer,analyze the material flow velocity of particle groups in each area of each layer of screen surface under different working conditions,and obtain the motion state of particle groups on each layer of screen surface.Study the variation of material layer thickness under different working conditions,and divide the material layer thickness into thin layer,medium layer,and thick layer based on the sieve hole size.Explore the evolution process of material layer distribution on each sieve surface with increasing feed volume.From the perspective of different feeding methods,a comparative analysis was conducted on the differences between multi-layer and single-layer sieves during the screening process.It was found that the unique feeding method of multi-layer sieves can indeed increase the probability of touching the sieve,leading to an increase in screening efficiency.Explore the impact of process parameters on total screening efficiency,volumetric screening efficiency,and partial screening efficiency,and determine the optimal level of each factor.Design a four factor and three level experimental plan based on the BBD response surface method,obtain 29 sets of simulation data through EDEM simulation,perform variance analysis,diagnose the closest model,and establish response surface fitting equations for the screening efficiency of each layer of sieve surface;Analyze the interaction,significance ranking,and optimal process parameters among various factors.Due to the different values of the optimal process parameters for the screening efficiency of each layer of screen surface,the response surface fitting equation for the screening efficiency of each layer of screen surface is used as the objective function.By using multi-objective optimization,the Pareto optimal solution set is obtained,and a set of ideal solutions is obtained through traversal.This article enriches the theory of vibration screening and provides a theoretical basis for the development of multi-layer screening equipment.This thesis has 41 figures,28 tables,and 102 references.