THE INFLUENCE OF LIQUID SPRAY RATE AND ATOMIZING PRESSURE ON THE SIZEOF SPRAY DROPLETS AND SPHEROIDS

The effects of liquid spray rate and atomizing pressure on the size of spray droplets and spheroids were investigated in this study. The ran ge of droplet sizes tended to narrow and relatively smaller droplets w ere formed at higher atomizing pressures. When liquid spray rate was i ncreased, the droplets were larger and had a wider size range. Althoug h alterations in liquid spray rate could affect spray droplet size, gr eater changes in droplet size were achieved by varying atomizing press ure. In these investigations, changes in spray droplet size and atomiz ing pressure did not appear to greatly affect mean spheroid size. Howe ver, the presence of an atomizing pressure was necessary for the even distribution of the moistening liquid to reduce localized overwetting during spheronization by rotary processing. The amount of oversized pa rticles may thus be decreased and a more uniformly sized yield may be achieved with the use of relatively higher atomizing pressures. With a fixed volume of moistening liquid sufficient for spheronization, larg er spheroids were produced with increasing liquid spray rates. The inc reased wetting per unit time resulted in the formation of larger nucle i and enhanced the growth rate of spheroids.