Design and Experiment of Pneumatic Precision Hill-drop Drilling Seed Metering Device for Hybrid Rice

Abstract:

Paddy rice is one of the most important fine food crops that feed the largest proportion of the world’s population. There are two planting patterns of paddy rice called direct seeding and transplanting. In order to realize precision hill direct seeding of hybrid rice in field and solve the problem of budded seed overhead and jaming in seeding box, a pneumatic seed metering device for hybrid rice budded seed was designed based on the seeding principle of air suction-air blowing. The seed metering device used cam, pushing rod and combing strips to solve the problem of rice budded seeds’ mobility. The seeding plate which had groups of suction holes could absorb 2~4 rice budded seeds. The seed metering device was constituted by seed box, cam, push rod, seeding axis, seeding plate, air chamber, flange and so on, by which two to four bud seeds could be sucked and dropped at the same time. The adsorption mechanism of budded seed in seed filling area was analyzed in the paper theoretically. An equation of vacuum degree in suction chamber was built. The paper launched bench experiment of doublesided pneumatic seed metering device and studied the relationship between seeding performance and combing device，rotational speed of seeding plate. The orthogonal experiment was done which took the diameter of suction hole, rotational speed of seeding plate and vacuum degree of air chamber as factors. The experiment result showed that the combing strips could stir rice budded seeds. The orthogonal experiment indicated that the optimal condition for the seed metering device is as follows: when the rotational speed is 15r/min, the vacuum degree is 3.5kPa and the diameter of suction hole is 1.6mm. And the experiment in field indicated that the device meets the agronomic requirement of planting rice budded seed.