往复式茶叶振动抖筛机优化设计与试验

Optimization Design and Experiment of Reciprocating TeaVibrating - sifting Machine

抖筛是茶叶精制的重要环节,直接影响茶坯的净度,针对茶叶抖筛过程中抖筛机理(清筛)不清晰而导致抖筛过程中存在茶叶断碎以及挂网等问题,本文研究茶叶在筛床上的抖筛规律,建立茶叶颗粒沿筛床上下运动、离开筛面被抛起运动和落到筛孔后碰撞运动三段筛分过程的动力学模型。结合茶叶在筛床上的抖筛规律,通过EDEM建立茶叶筛床的仿真模型,对茶叶在筛床上的速度与受力进行分析,确定筛床曲柄转速、筛面倾斜角和曲柄半径的最佳参数。最后通过三因素三水平的正交试验,确定实际筛分情况下的最优参数与得出各个因素对误筛率和生产率的影响由大到小为筛面倾斜角、曲柄转速、曲柄半径。试验结果表明,当曲柄转速为247.99 r/min、筛面倾斜角为2.60°、曲柄半径为23.11 mm时,误筛率和生产率分别为5.3%和440 kg/(m~2·h),与优化结果误差在允许范围内。

Tea is a kind of global beverage,the mechanized tea refining operation is an important part of the entire tea mechanization process.Vibrating-sifting is an integral part of tea refining,which directly affects the purity of tea.In view of the unclear mechanism of vibrating-sifting in the process of tea vibrating-sifting,there are problems such as broken tea and hanging mesh,which affect the vibratingsifting efficiency.The motion law of tea on the screen bed was researched,the dynamic model of the three-stage screening process of tea moving up and down along the screen bed was established,which was thrown up from the screen surface and colliding after falling to the screen hole,combined the motion law of tea on the screen bed,a simulation model of tea screen bed was established through EDEM,and the speed and force of tea on the screen bed were analyzed.The best parameters were crank radius,rotating speed of the crank and the inclined angle of the screen surface.Finally,through the orthogonal test of three factors and three levels,the software Design-Expert was used to analyze and optimize the experimental data and determine the optimal parameters.The significance order of each factor on the error screening rate and productivity was obtained.The order of significance for the error-sifting rate was the inclination angle of sifting bed,crank speed and crank radius,while the significant order of the productivity was the inclination angle of sifting bed,crank speed and crank radius.When the crank speed was 247.99 r/min,the inclination angle of the sieve bed was 2.60°,the crank radius was 23.11 mm,the error screening rate and productivity were 5.3%and 440 kg/(m2·h),respectively,compared with the optimization result,the error was within the allowable range.The research result had a significant reference value for improving the screening efficiency of vibrating-shifting machine for tea.