Research And Simulation On Unloading Process Of Chain-bucket Stacker

Storage yard is a place for material turnover and is very important to the port. The stockpiling and turnover efficiency are two important indexes for storage yard, they directly affect the efficiency of storage yard and the benefit of port. The bulk of stacker is an important equipment of storage yard, and now the widely used mechanics are bucket wheel stacker 、 bucket type lifting machine and bridge type stacker. A scholar come from Wuhan University of Technology put forward a new model-- chain bucket stacker, which have high efficiency, low energy consumption, flexible movement and is good for environment etc. It is suitable for bulk cargo handling technology system of dump truck and will replace the current loader forklift equipment.Chain-bucket stacker combinates the characteristics of Bucket-type lift machine, Screw conveyor, Belt conveyor, the material was transported to a certain height through three kinds of transmission mode, such as vertical lifting, horizontal transfer of material, incline lift. By using tire type walking mechanism, the chain bucket stacker can work in any position of the yard, due to the continuous feeding, lifting, stacking material, the efficiency of pilling high is greatly improved. At the same time, due to the structure of vertical transport, so that the pile height increase, thus increase the amount of storage and the utilization rate of the storage yard.The paper mainly studies the motion characteristics of materials in the process of vertical transportation of materials by the chain bucket stacker. It analyses the stress state of particles through granular mechanics, the equilibrium condition and the motion state of particles in the inclined trough, then derived the minimum angle of inclined trough which the particle sliding. It analyses the discharge mode in the process of rotation, and the change of slip surface of material in the process of lifting, rotation and tilt down, Establishes the force balance equation through analyses the force of particle in three stages, then derived the differential equations of motion of particles in the bucket. According to the differential equation of motion of particles, we can calculate the initial velocity of particle when it is unloaded, then establishes the equation of motion of the particle when it does parabolic motion. Determine the initial discharging angle when the chain bucket rotating, find out some typical particles position,and draw out their movement trajectory according to the equation of motion of particles, then simulate contour line of the whole material flow, design the bucket cover according to the outline of material flow.By analyzing the trajectory of the latest unloading particle, we can verify that the chain bucket unloading whether is completed. Finally, through The discrete element software EDEM, we can simulate entire discharging process and make analyze to the results; setting up different chain traction speed, different inclination angle, different bucket chain spacing to make simulation, then get a group of best parameters of unloading.