Design and Experiment of Precision Seed Metering Device for Flow Adsorption of Quinoa Seeds

This paper proposes a solution to the problem of tight population in the filling area of traditional air suction seed metering devices during quinoa sowing, which leads to inaccurate adsorption. The proposed method disperses the population into a stable seed flow and absorbs the seeds in a flow posture. The flow adsorption precision seed metering device is designed and improved, and the key structure parameters are optimized based on the shape and size parameters of quinoa seeds. A four-factor and three-level response surface orthogonal test is conducted using the Box-Behnken experimental design. The number of seeds, flow angle, negative pressure at the suction hole, and advancing speed are taken as experimental factors, and the qualified index of grain number per hole, qualified index of hole distance, and coefficient of variation of hole distance are used as evaluation indices. The results are optimized using extreme value theory, and it is found that when the seed amount is 5.82 mm, the flow angle is 31.08 degrees, the negative pressure of the air chamber is 1.7 kPa, and the advancing speed is 3.82 km center dot h-1, and the qualified index of hole number is 94.37%, the qualified index of hole distance is 95.39%, and the coefficient of variation of hole distance is 4.51%. The results are in general agreement with the prediction through the bench validation test, which meets the requirements of quinoa seed metering devices.