Design And Experiment Of Tea Drying And Shaping Machine

Tea drying and shaping are the last two processes in the processing of common green tea,and their effects are directly related to the quality of the finished tea.However,the current production and processing of common green tea is mechanized and has a low degree of automation,which restricts the development of the tea industry.In order to improve the efficiency of roasting and polishing of common green tea,improve the quality of finished tea,and at the same time realize the processing requirements of automation and cleaning,this paper designs an automatic machine that integrates tea drying and shaping,and uses biomass fuel as energy.The unit is of great significance for reducing labor costs and improving work efficiency.The main research contents are as follows:(1)Analyze tea physical property parameters and drying principle.Determine the physical parameters for the green tea production and processing among four links,including the moisture content of common green tea,bulk density,Angle of repose,static friction factor,specific heat and thermal conductivity,and analysis the Fried dry moisture content is in commonly 5%-6% of tea is the best,for the tea processing machinery research and development design provides a theoretical reference.(2)Machine structure and key components design.Investigate the process requirements of tea drying and shaping,analyze the structure of the existing tea drying and shaping machine,and determine the functions and related parameters of the drying machine.Structural design of key components: drying drum,stir plate,transmission system,frame,polishing drum,determine the relevant design parameters.In addition,the biomass pellet burner used by the unit was analyzed.The whole unit can realize feeding,drying,discharging and polishing functions at one time.(3)Analysis of tea drying and shaping process based on discrete element simulation.Use software of EDEM to carry out single-factor simulation experiment.Take the average particle velocity,extrusion pressure,dispersion degree and temperature rise rate as indexes.The rotation speed of stir-drying machine was set at 18-22r/min and the stir-drying temperature was set at 160℃～200℃ initially.(4)Prototype test of tea drying and shaping unit.On the basis of single factor simulation,produce the prototype of tea drying and shaping unit.With large moisture content of green tea,tea break rate as the evaluation index,the drum rotating speed,Fried dry temperature,Fried dry time three factors orthogonal test design,optimization experiment shows that the three kinds of controllable parameters in moisture content,the influence of the rate of broken tea industry in the order: the speculation dry temperature,drying time and drum rotational speed.Through design-Expert optimization solution,the optimal parameter combination was obtained as follows: drum rotation speed 19r/min,drying temperature 184℃,drying time 80 min.With this parameter,the verification test was carried out.The average water content was 5.47%,and the average broken tea rate was1.82%.Taking the broken tea rate,appearance color and compactness of bulk green tea before and after shaping as the evaluation indexes,it is verified that the drying and shaping unit has good working effect.The unit of tea drying and shaping for common green tea studied in this paper has good practicability,meets the agronomic requirements of bulk green tea processing,has a high degree of automation and cleanliness,can realize mass production and processing,and has high work efficiency,which provides a design idea for the promotion of modern tea processing equipment.