双层平筛式半夏收获机设计与试验

针对丘陵山区地带半夏人工收获劳动强度大、效率低、收获期长、收获损失率高,而现有的根茎类收获机械直接应用于半夏时存在采收不彻底、分离效果不佳、二次除杂工作量大等问题的现状,结合种植农艺,设计一种半夏收获机。样机主要由挖掘装置、升运装置、筛分装置和收集装置组成。用解析法分析确定升运装置的升运速度,进而确定升运量和计算功率;分析筛面上半夏与土壤复合物竖直、水平运动的条件,确定偏心轮转速范围为530~753 r·min^-1,偏心距范围为15~25 mm;分析半夏从升运装置到筛面的运动特性,确定升运装置顶端距离筛面的高度为350 mm。用EDEM软件模拟筛分过程,验证参数选择的合理性。仿真结果表明:平筛频率为9 Hz、幅值为20 mm时,筛面复合物颗粒分布均匀;复合物可以完成后滑、前移和抛起运动,无淤积等筛分不畅现象;复合物颗粒跳动周期性明显,竖直方向总速度差别明显,所选参数符合筛分装置设计要求。半夏收获试验样机田间试验表明:当行进速度为0.5 m·s^-1、挖掘深度为83 mm、拖拉机输出转速为540 r·min^-1时,挖净率为97.3%,伤损率为3.51%,含杂率为4.97%,符合根茎类中药材收获机质量评价技术规范要求和样机设计要求。研究成果可为半夏收获机的设计与研制提供应用实例与技术参考。

Design and experiment of double layer flat screen type Pinellia ternate harvester

The artificial harvest of Pinellia ternata in hilly and mountainous areas has problems of high labor intensity, low efficiency, long harvest period, high harvest loss rate, etc. Meanwhile, the application of current harvester also has shortcomings of incomplete harvest, poor separation effect, large workload of secondary impurity removal and so on. To overcome these problems, a Pinellia ternata harvester was designed. The prototype is mainly composed of digging device, lifting device, screening device and collection device. Analytical method is used to analyze and determine the lifting speed of the lifting device, hence determine the lifting capacity and power.The conditions of vertical and horizontal movement of Pinellia ternata and soil complex is analyzed, and the eccentric wheel speed is determined in the range of 530-753 r·min ^-1, along with the eccentric distance range of 15-25 mm.By analyzing the motion characteristics of Pinellia ternata from the lifting device to the sieve surface, the height of the top of the lifting device to the sieve surface is determined as 350 mm. EDEM software is used to simulate the screening process to verify the rationality of parameter selection. The simulation results show that when the frequency of the flat screen is 9 Hz and the amplitude is 20 mm, the distribution of the complex particles on the sieve surface is uniform.The complex particles can complete the backward movement, forward movement and throwing movement, without siltation and other screening obstructions.The periodicity of the complex particles and the difference of the total velocity in the vertical direction are obvious, indicating that the design of the screening device with selected parameters are reasonable. The field test of the prototype of Pinellia ternata harvest shows that when the speed is 0.5 m·s ^-1, the digging depth is 83 mm, and the output speed of the tractor is 540 r·min^-1, the net excavation ratio is 97.3%, the damage rate is 3.51%, and the impurity content is 4.97%. The test indexes all meet the technical requirements of quality evaluation and prototype design requirements. This study can provide application examples and technical references for the design and development of Pinellia ternata harvester.