Analysis on seeding process of pneumatic cylinder-type centralized rapeseed precision metering device

Abstract: In order to obtain the relationship model between required negative and positive pressures values and the structural and operating parameters in the main metering processes at the absorbing, retaining and dropping stages，the seeding process of pneumatic cylinder-type centralized rapeseed precision metering device were analyzed. Through analyzing the influence of operational and structural parameters on the performance of pneumatic cylinder-type centralized rapeseed precision metering device, the working principle of the pneumatic cylinder-type centralized precision metering device was summarized, and its basic configuration was designed. Dynamic and kinematics models were established in the main metering processes at the absorbing, retaining and dropping stages, and Extended Discrete Element Method software was used for the simulation and calculation of absorbing process, based on which the relationship model between required negative and positive pressures values and the structural and operating parameters were established in seeding process. The results of extended discrete element method simulation analysis indicated that in order to ensure the reliable work of the metering device, the height of seeds should be limited within the 0.65Dg, which was verified by the results obtained from our preliminary tests. Then the JPS-12 test-rig for the performance of the rapeseed metering device was adopted to conduct the single factor experiments, which showed that the quality index reached above 89.1% and the coefficient variation was 3.76% when the rotational speed was 20 r/min and the positive pressure value was 2 200 Pa and the vacuum was -2 200 Pa. The experimental results were in accordance with the analytical result of dynamic model. The analysis provided theoretical foundation for optimizing the operational and structural parameters of the centralized metering device.