Electrostatic induction charging of pollen suspensions

Induction charging of almond pollen (Fritz cultivar) has been investigated in this paper. Harvested pollen was separated from die anther fragments and other impurities using a purpose-built mechanical pollen purifier. For dispersing the pollen, special conducting liquid medium was prepared possessing an osmotic pressure equal to that of the cytoplasm within the pollen cells. The pollen-carrier liquid mixture was electrostatically charged and sprayed using an induction spray charger. The spray cloud current of the electrostatically sprayed carrier liquid was seen to increase approximately linearly with atomizing air pressure and liquid flowrate. As pollen-liquid suspension was electrostatically sprayed at 75 mL/min for different induction voltages of 200 to 1000 V, spray cloud current measured with an ionization probe was found to increase monotonically from -2.6 pA to -13.3 pA with a corresponding charge-to-mass of -9.9 mC/kg at 1000 V. Varying the pollen mass loading over a range of 0.5 g/L to 10 g/L showed that the spray cloud current remained constant within experimental error at -13.3 μA for an electrode voltage of 1000 V at a particulate-liquid flowrate of 75 mL/min. These results indicate that pollen can be successfully metered in the specially formulated carrier liquid and electrostatically charged using an embedded-electrode induction charging nozzle applicable for further development of an electrostatically enhanced pollination process for increasing the production efficiency of high-value crops