Research On Impact And Friction Of Bulk Coal In Middle Trough

Scraper conveyor is the key equipment for bulk transportation,and the middle pan is the key component of the scraper conveyor,whose rationality and reliability of the design are related to the operating efficiency and life time of the scraper conveyor.In recent years,with the wide use of the heavy-duty scraper conveyor,the wear of middle pan is more prominent for the scraper conveyor.But because of the heavy weight of the the middle pan and the replacement trouble,it is very important to study the mechanical properties and wear characteristics of the middle pan under the force of the coal bulk for the scraper conveyor.Based on the research method of combining theory,simulation and experiment,the wear resistance of the middle pan is taken as the research goal.This paper studies the force and friction characteristics of the middle pan acted by the coal bulk,which gives some guidance for improving the life time of the middle pan of the scraper conveyor.In this paper,the key components of the middle pan friction pairs of the scraper conveyor and the coal bulk are taken as the objects of study.Based on the dispersion characteristics of the coal bulk,the wear characteristics of the middle pan under the impact and the tricuspid friction are analyzed in terms of the theoretical calculation,and the influencing factors of wear are obtained.Further,the simulation model of the middle pan friction pairs is established by EDEM discrete element simulation software,and the correctness of the simulation model is verified by the particle distribution and the main wearing area.In order to analyze the force and wear of the middle pan in different areas,the force and wear characteristics of the middle pan under different structure forms,different coal properties and different working conditions are studied by controlling variables in the area of coal falling and transportation.It is found that the wear of the middle pan in the transportation area is mainly concentrated on the chain of the scraper conveyor for transporting the coal bulk.The influence on the wear and the characteristics of the middle pan under different influencing factors are not exactly same in the area of coal falling and transportation.The wear-resistant plan of the scraper conveyor is given under different circumstances.The the wear at the chain was studied by the microscopic simulation experiments.The typical lignite,coking coal and anthracite were selected as medium of the three-body friction.When different kinds of coal were selected as the friction medium,The effect of positive pressure and sliding speed on the friction coefficient and wear mass loss were analyzed for the 16Mn(the material of middle pan's plate)and 40Cr(the material of the chain).It shows that the wear is the largest when the anthracite was selected as the friction medium,and the wear gradually increases with the increase of the positive pressure.But the wear increases first and then decreases with the increase of the sliding speed.The worn surface wear of the plate's material is mainly the furrow produced by the abrasive wear.The width and depth of the furrow are larger when the particle is larger.When the particle size of the coal bulk is about 40 mesh,the increase of the particle size does not significantly affect the variation of the wear amount.