Improving the process of seed dosing with a vacuum seed-placing device using corn as an example

The constant increase in the speeds of machine and tractor units, the tightening of quality requirements for the implementation of technological operations determine a certain level of design perfection of the sowing devices of row-crop seed drills. In this regard, the purpose of the presented research is to optimize the design of a vacuum seed-placing device, implemented so that to feed corn seeds as an example, which allows not only to ensure their stable dosing, but also helps to simplify the operation of the seeding machine. To achieve this goal, a diagram of a seed-placing device with a pneumatic tedding effect has been proposed, which differs from serial ones in a stepped cutout in the gasket of the vacuum chamber, the presence of additional holes made in the body of the sowing disk, and the absence of a dropper of «excess» seeds. The presented research is aimed at optimizing the parameters and operating modes of a vacuum seed-placing device of the proposed design when sowing corn seeds. The study was carried out using the methods of factorial experiments which generally confirmed both the effectiveness of using pneumatic tedding effect to increase the gripping ability of suction holes, and the possibility of reducing the diameter of suction holes to “fight” the formation of group feeds, which presumably will eliminate the dropper of «excess» seeds from the design of the device. Under the given experimental conditions, the best quality of operation of the device, corresponding to the current agricultural requirements, was mostly ensured at the diameter of the suction holes (dоо) equal to 3,5 mm and the operating vacuum (H) in the plane of the suction holes close to 5,5 kPa. The obtained results suggest the possibility of a further increase in the quality of its operation when metering corn seeds without using a dropper of ‘excess’ seeds at dоо > 3,5 mm, which indicates the need for additional research in this direction.