Design and Construction of a Pneumatic Harvesting and Cleaning Machine for Jojoba Seeds

Abstract. A pneumatic harvesting and cleaning machine was designed and constructed to harvest jojoba seeds from the soil surface. Jojoba seeds do not mature at once, whenever part of seeds reach maturation they fall naturally to the ground. So, more than one harvesting in the season may be necessary, depending upon weather conditions and grower preferences. Some of the physical and aerodynamic characteristics of jojoba seeds and other material mixes with the seeds were measured. The pneumatic harvesting machine was constructed at the workshop of Agricultural and Biosystems Engineering Department, Alexandria University, Egypt. The performance of the harvesting machine was investigated under different operation factors such as air suction velocity (m/s), machine forward speed (km/h), length of the suction hose (m), clearance of the suction hose inlet above the soil surface (cm), and the percentage of materials other than jojoba seeds. It was found that the best-operating conditions are air velocity 30 m/s, hose length 2.5 m, suction hose clearance above 5 cm from the soil surface, machine forward speed 1.2 km/h, and the ratio of seeds to material other than seeds 0.5. The research is atrial to produce a harvesting machine and then evaluated its performance under simulated field conditions. Although the performance of the harvester was considered satisfactory, and it has already accepted in Egypt as a patent with a number (2014121991/2014); it requires additional modifications to make it commercial applicable.