Dynamic Research Of Dust In Powder Filling Packaging And Dust Removal Optimization

With powder material requirements increasing day by day,dust pollution,caused by powder packaging,has been more and more serious in recent years.During the powder packaging,the dust not only causes damage to production equipment,affecting packaging precision,much harm to workers' health.With automatic powder packaging equipment as basis,this program proposes the dust-clearing system.Theory analysis and model simulation are used to study the factors,which affect the dust quantity and control the dust in powder filling.And on the basis of the particle force analysis,it is aimed to calculate the equilibrium equation,design dust hood and dust-clearing parameters.Finally the dust-clearing system is integrated,and the powder packaging craft is designed to make the work cycle steps.Through these researches,the program aims to explore the general rule of powder falling and influencing factors,and provides optimization parameters for dust control in the process of packaging.The following are the main contents:(1)Analysis and investigation of the research object,and determination of research contents.By analyzing the actual situation and the harm in the process of powder packaging,investigating the production status and developing trend of this industry,it is used to determine the aim and significance of this program.On the basis of reading reference and production survey,the dust-raising about the present situation and progress of home and abroad is analyzed,clearing the thoughts of the developing trend in gas-solid two phase theory.The ideas and measures are also analyzed about dust-clearing in packaging.Above these work,main research contents and direction are clear and specific.(2)Analysis of the dust-raising theory in powder filling.Particle and powder are studied on the basic physical properties.The definition of particle size,particle size distribution and powder density,flow ability are confirmed.Besides,the difference and connection between particle density and powder density are analyzed.These theories help to understand the basic conditions of dust-raising.According to the phenomenon of powder falling,the integrated process of particles and air flow is defined as the gas-solid coupling effect.The dust raising factors are analyzed and summarized.Especially for powder filling in bag,three keys factors,including the particle density,the mass flow rate and the drop height,are proposed.At the end,on the basis of powder dust-raising theory,the thought of the dust-clearing system is proposed.(3)The equilibrium conditions and the theoretical calculation of particle in dust hood.According to the gas-solid flow theory and particle movement in reality,the stress of the flow to particle,the field force and other forces to particle are analyzed.By formula derivation of particle stress,it is found that the pressure force to particle is equal to the impact of airflow force.By estimating the force magnitude and analyzing the effect of turbulent Reynolds number,the upper limit and lower limit equilibrium equation of particles are provided.And the equations are simplified as air velocity and particle size affecting particle stress.Finally,MATLAB is used to draw balance equation and analyze the theoretical wind speed of dust-clearing conditions.(4)Simulation analysis and optimal conditions for dust-clearing during the powder filling.Based on the gas-solid flow theory,the mechanism simulation is analyzed to selected appropriate simulation model and calculation conditions.According to the actual production and the national standard,the powder bag model is built and the model parameters and simulation conditions are set up.The independence of model grid is also tested and verified.Above these,the particle density,mass flow rate and falling drop height are explored in the form of experiment investigation about the effect of powder filling.The particle velocity distribution,particle residence time,flow velocity distribution and particle size distribution are analyzed to compare the effect of particles in bag and air flow on the actual situation.Eventually reasonable height range is determined during the powder filling which produce the least dust quantity.(5)The optimization design of dust-clearing system.According to the theory of dust hood settings and the actual situation,the dust hood is designed.And the dust hood model is established.The simulation parameters of model are set up to simulate the process of dust-clearing.The particle velocity distribution,flow velocity distribution and particle distribution proportion are used to explore reasonable wind speed.The dusting power is calculated,and these parameters of dust-clearing are integrated to design dust-clearing system design.According to the powder packaging craft,the work cycle is drew.