Objective Aiming at the problem that the existing seed cleaning device of the vegetable plug seedling seeder is not effective in cleaning seeds, resulting in low seed filling qualification rate and high reseeding rate, a seed cleaning device integrating mechanical type, air blowing and electric control is designed.

Method Combined with kinematics and dynamics theory, the structure of the three-stage seed cleaning device was designed. The air flow stability in different air-inlet and air-outlet structures of the air-blown seed cleaning device was analyzed by using the fluent module in Ansys software. On the basis of theoretical analysis and simulation analysis, the speed of seeding device, negative pressure of seeding device, positive pressure of seed cleaning device and seed diameter were selected as the experimental factors. According to the agronomy requirements, qualified rate of single seed filling and reseeding rate were selected as test indexes to carry out four-factor and three-level quadratic regression orthogonal test. The best parameter combination was obtained based on the experimental data.

Result According to the simulation analysis, it is concluded that the air blowing type structure with the air-inlet circular arc nozzle at the middle end had the best seed cleaning effect. The best parameter combination for seed metering was summarized from the bench test. When the speed of the seeding device was 0.17 r/s, and the seed diameter was 1.5 mm, the negative pressure of the seeding device was 0.6 kPa, and the positive pressure of the air blowing seed cleaning device was 0.3 kPa, the average qualified rate of single seed filling was 95.31%, and the average reseeding rate was 0.2%.

Conclusion The design of the seed cleaning device meets the agronomic requirements of vegetable sowing, which can effectively improve the qualified rate of seed filling and reduce the reseeding rate, and provide theoretical guidance for production practice.