Design and construction of a pneumatic harvesting and cleaning machine for jojoba seeds

Abstract

A pneumatic harvesting, separating, and cleaning machine was designed and constructed to collect Jojoba seeds from the soil surface using cyclonic separation process. 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. To design the machine successfully, some of the physical and aerodynamic characteristics of Jojoba seeds and other undesired materials mix 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 conditions such as suction air velocity, machine forward speed, length of the suction hose, clearance of the suction hose inlet above the soil surface, and the different ratios of materials other than Jojoba seeds (MOS). It was found that the best-operating conditions are when the suction air velocity is 30 m. s⁻¹, hose length is 2.5 m, suction hose clearance from the soil surface is 5 cm, machine forward speed is 1.2 km .h⁻¹, and the ratio of seeds to material other than seeds is 0.1. 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, it requires additional modifications and parts to make it commercial applicable.