Geldart Diagram – Another development that can be considered transformative that developed in another field of solids processing is the Geldart Diagram conceived with the idea of understanding how particles with different characteristics behaved in the fluidization operation. I believe that Geldart (1973) while working dominating in fluidization had an
impact on the whole solids processing field including pneumatic conveying. Through his classification of the various type of solid powder and their flowability conditions and results in pneumatic conveying can often be interpreted. Figure 3 presented here was recently proposed by Yang (2007) in his attempt to expand the analysis to high temperature and high pressure fluidization operations.