振动气吸式精密穴播机的排种性能

为了研究振动气吸式精密穴播机的排种性能，根据空气动力学理论，结合水稻的物料特性，分析了稻种的吸种过程及穴播机的吸种性能；根据振动理论，分析了薄层种子和厚层种子在种盘上的运动。种子抛掷条件与振动频率、种盘振幅和种层厚度有关，种层越厚，振动部件所要求的振动强度越大。对于杂交水稻种子精密穴播，当吸种高度大于1 mm时，气室负压随吸种高度的增加而迅速增大，当吸嘴口直径小于1 mm时，气室负压随吸嘴口直径的减小而迅速增大，较优的气室负压为10～15 kPa。试验研究表明，该穴播机播种合格率达97.7%，能完全满足杂交水稻精密穴播农艺要求。

Metering performance of the vibrational vacuum precision tray seeder

For studying the metering performance of the vibrational vacuum precision tray seeder, according to aerodynamics theory, combined with physical properties of rice seeds, the pick-up process and pick-up performance of the seeder were analyzed. Based on vibration theory, the motions of seeds in thin layers and in thick layers were analyzed as well. The vibration conditions under which seeds are to be throwing were related to vibration frequency, vibration amplitude of the seeds plate, and thickness of seeds in the plate, and stronger vibration intensity required for seeds was as seed layer became thicker. For hybrid rice metering, the depression of air in the chamber increased rapidly with decrease of the nozzle diameter while the diameter was lower than 1 mm, and the depression increased rapidly with increase of distance from nozzle opening and while the opening was higher than 1 mm. The test results indicated that the precision tray seeder fully met the agronomic requirements with qualified rate of seeding 97.7%.