Developing a new seed tube design to improve seeddistrubition uniformity of seed drills

Seeds drop from seed tubes with the effect of gravity for seed drills (uninterrupted row drills). Because trajectory of seeds in seed tube is different, dropping period of seeds is different. Whatever the regular seed flow starts from seed metering unit it becomes irregular flow while dropping in seed tube. This study is prepared to arrange the seed flow in seed tube just before dropping to furrow with the designing the new seed tube. For this reason, a tube including helicoids will be assembled with a conventional seed tube and seeds will flow on helicoids and therefore uniformity of seed flow will increase and falling speed of seeds to furrow will decrease. The developed seed tube was analyzed by kinematic analysis in SW 3D parametric solid modeling software. Designed seed tube was tested at the three heights of helicoids screw (100, 150, 200 mm), three pitch of helicoids (28, 32 ve 36 mm) and three slopes of seed tubes (horizontal angels of 70°, 80°, 90°), the best seed tube dimension was selected according to results of kinematic analysis. The selected seed tube was manufactured from 3D printer and subjected to laboratory and field tests at the speed of metering roller 10 min-1 and a seeding rate of 20 kg/da. In laboratory experiments seed flow was recorded with a high speed camera at a recording speed of 240 fps and the duration between succesive seeds and falling speed of seeds were determined and the mean, standard deviation and coefficient of variation values of these values were calculated. The coefficient of variation of 168.13% of the normal seed tube was decreased to 79.02% when the helix seed tube used. In the field experiments, coefficient of variation of 118.36% of the normal seed tube was decreased to 77.2% when the helix seed tube used. In the field experiments, the standard deviation of seed scattering decreased from 1.52 cm to 0.86 cm with the helicoid seed tube.