Simulation Research On Dust Diffusion Mechanism Of Vertical Packaging Machine And Dust Prevention Design

Automatic packaging machines usually have the problem of dust overflow in the working process.These dusts have serious hazards to worker health,environmental pollution,production safety,and equipment expectancy.Vertical packaging technology is an effective packaging method to effectively solve the dust overflow,but the fine dust in the blanking process and the horizontal sealing process is easy to diffuse into the air and cause dust to overflow.This thesis uses theoretical analysis and computer simulation to research the problem of dust overflow in the blanking process and horizontal sealing process of the vertical packaging machine.The main content and results of thesis are as follows:According to the movement characteristics of the material particles in the vertical packaging machine,the mechanism of dust overflow and its influencing factors are analyzed.It is concluded that induced air flow and shear air flow are the main factors for dust generation and overflow.Fick’s law of diffusion is used to derive the theoretical model of dust diffusion,and MATLAB is used to simulate the dust diffusion in the blanking process.The Dense Discrete Phase Model(DDPM)in the FLUENT software is used to simulate the material filling process of the blanking process,analyze the falling movement of dust particles and the internal flow field distribution in this process.It is concluded that the velocity of the particles in the falling process increases with time,the particle flow gradually becomes loose,and the particles collide with the bottom of the bag and there will be particle splash phenomenon.The exit of the gap area is monitored,and the dust content of the air at the exit is calculated to reach 579.57g/m~3.By Using FLUENT’s dynamic grid to simulate the horizontal sealing process,the internal flow field movement and the movement of dust are analyzed,and the amount of spilled dust and the volume of dust-containing air are calculated.The dust content of air at the outlet reaches 1221.88g/ m~3 by calculation,providing a theoretical basis for the design of the dust hood.The influence of the bag length of the packaging bag and the moving speed of the horizontal sealing seat on the amount of internal air escape is studied.The longer the packaging bag is,the less the volume of leaked air is;the faster the horizontal sealing seat moves,the faster the air escapes.But the total amount of air escaping remains unchanged.The direction of the negative pressure suction of the dust removal hood is analyzed,and the parameters of the negative pressure suction are optimized to provide a theoretical basis for the structure parameters of the dust removal hood.According to the requirements and constraints of the vertical sealing gap in the blanking process and the horizontal sealing process,the type selection and engineering design of the vertical sealing module are carried out.