Evaporation of clearcoat solvents from a rotary bell atomizer and its relationship with bell speed, flow rate, and electrostatic potential

Abstract

The relations between evaporation of clearcoat solvents and various operating parameters of the spray from a rotary bell atomizer were measured using a particle dynamic anemometer (PDA). The robot arm holding the spray applicator was moved relative to the PDA so that the volume flux at different parts of the spray could be measured. The difference in total flux between two planes, perpendicular to the spray axis, was considered to be equal to the evaporation. Evaporation was found to increase with increasing bell speed. Evaporation also increased with increasing coatings flow rate from 100 to 200 cm3/s flow rate, but not for a further increase to 300 cm3/s. Higher electrostatic potential, bell speed, and lower flow rate decrease the mean particle diameter. Particle mean velocity increases with increasing bell speed and flow rate. Coatings flow rate, bell speed, electrostatic potential, and the interaction between flow rate and bell speed were significant factors affecting evaporation rate. Of the former three, coatings flow rate was the most influential.