An air-jet singulator was designed and developed to work with a Gaspardo SV-255 planter and a Model 520 planter. The commonly used mechanical singulators on these planters are sensitive to a back plate wear problem. The singulation efficiency of mechanical singulators deteriorates with time due to this back plate wear problem. The SV-255 planter was tested using three vacuum levels (250, 350, and 450 mm of water), three levels of air-jet pressure (20.7, 27.6, and 34.5 kPa), three levels of metering plate linear speed (63.6, 130.7, and 204.3 mm/s), and three different positions of the air-jet singulator. The model 520 planter was tested at three vacuum levels (381 mm, 508 mm, and 635 mm of water), three levels of singulation pressure (2.49 kPa, 3.11 kPa, and 3.73 kPa) and three levels of metering hole speed (71.6 mm/s, 119.4 mm/s, and 167 mm/s). These tests indicated that the air-jet singulator worked very well - in fact, better than brand new mechanical singulators.
