Particle sizes: Sieves & Image Analysis

Particle size distributions as determined by ASABE forage standard (ANSI/ASAE S424.1, DEC01, 2006) are shown in Figs 5 & 6 for a knife mill equipped with screen sizes of 12.7 and 50.8 mm, respectively. Knife mill screen size determined characteristic shapes in particle size spectra curves. For example, the 12.7 mm screen resulted in somewhat of a normal distribution in particle sizes, whereas the other screen sizes each had skewed normal distributions. Ratios of mass fractions contained in small versus large particles differed with the different screen sizes. 

Fig. 5. Sieve particle size results for switchgrass size reduction at various mass input rates and rotor speeds in a knife mill equipped with a 12.7 mm screen.

Fig. 6. Sieve particle size results for switchgrass size reduction at various mass input rates and rotor speeds in a knife mill equipped with a 50.8 mm screen.