Spout shapes changes

Note that with a larger orifice, spout shape changed to type c Tapering of spout dia. near top occurred only for H > 7.9 in. 

The shape and dimensions of the active carbon particles change as a result of their processing in the spouted bed, as shown schematically for a particle with layers removed to different degrees in Figure 2. 

However, in various coating and granulation experiments a change in the shape of the distribution is observed, for example a dispersion of the distribution. In Fig. 7.45 the results of five different coating experiments are shown, which were conducted in Wurster equipment, a conventional fluidized bed apparatus (FB) in top and bottom spray configuration, and a spouted bed apparatus (SB) in top and bottom spray configuration. Although identical initial conditions were used and the process conditions are comparable (see Tab. 7.6), different final distributions are achieved. This effect cannot be explained by the common model of Eq. 7.34, but it underlines the influence that different types of equipment with different flow patterns may have on the process result. 

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