温室穴盘育苗劣质钵苗螺旋式剔除机构设计与试验

Design and Test of Spiral Rejection Mechanism for Inferior Bowl Seedlings

在温室穴盘育苗过程中,有5%~20%的穴孔存在漏播、发育不良等现象,为提高穴盘利用率,保证成品苗质量,需要将这些劣苗基质块干净剔除并及时补充健康钵苗。常见的剔除末端主要有指铲式、气吸式,但存在指铲式剔苗方式易造成钵体松散破碎难以抓取、气吸式剔苗在高含水率下剔净率低等问题,为此本文设计了一种螺旋式劣苗剔除装置。该装置使用输送带移动穴盘,升降模组带动横移模块进行升降,横移模块上安装两个剔苗末端执行器,剔苗末端执行器使用螺旋叶片对基质进行破碎,通过螺旋输送和负压吸附的方式将穴孔中的基质破碎并输送到顶部蓄土槽中,升降时自动转移到排土槽中。以200孔带基质穴盘为研究对象,对螺旋叶片的升土方式进行理论分析,确定相关设计参数,并对螺旋式劣苗剔除装置进行路径规划。搭建螺旋式劣苗剔除装置,开展螺旋式基质剔除四因素三水平正交试验,结果表明,试验因素的影响由大到小为凹口切角、螺距、转速、升降速度,确定最优参数为:螺距16 mm、凹口切角10°、转速2500 r/min、升降速度10 mm/s。在最优参数组合下进行性能验证试验,结果表明,剔苗机构作业效率平均为832孔/h(约42盘/h),基质平均剔净率在83%以上,满足剔补苗作业需求。

In the process of seedling raising in the greenhouse hole tray,about 5%to 20%of the holes had the phenomenon of missed seeding,stunted development,etc.In order to improve the utilization rate of the hole tray and ensure the quality of the finished seedlings,it was necessary to remove the inferior seedling substrate block neatly and replenish the healthy bowl seedlings in time.There were two common rejection ends:finger shovel type and air suction type.There were problems such as the finger shovel type seedling removal method and the air suction seedling removal method.The finger shovel type seedling was easy to cause the bowl body to be loose,fragile and difficult to grasp and the air suction seedling removal method had a low rejection rate under high moisture content.The conveyor belt was used to move the hole plate,and the lifting module drove the traversing module to lift,and two seedling removal end effector were installed on the traversing module,and the culling end-effector used spiral blades to break up the substrate.The matrix in the hole was broken and transported to the top soil storage tank by means of spiral conveying and negative pressure adsorption,and automatically transferred it to the soil discharge tank when it was lifted.Taking the 200-hole strip matrix cavity disc as the research object,the soil lifting mode of the spiral blade was theoretically analyzed and the relevant design parameters were determined,and the path planning of the spiral inferior seedling rejection device was carried out.The test platform of the spiral inferior seedling rejection device was built and the four-factor and three-level orthogonal experimental research on the removal of spiral substrate was carried out.The influence of experimental factors,from large to small,included notch cutting angle,pitch,rotation speed and lifting speed.The optimal parameters were determined to be 16 mm pitch,10°notch cutting angle,2500 r/min rotation speed and 10 mm/s lifting speed.The performance verification test was carried out under the optimal combination of parameters,and the results showed that the average operating efficiency of the whole machine was 832 holes/h(42 trays/h).The average rejection rate of the substrate was over 83%,which met the needs of the seedling rejection operation.