Dust Control Handbook for Industrial Minerals Mining and Processing

Cascading Loading SpoutFigure 7.5 illustrates a schematic and photograph [Cleveland Cascade 2010] of a loading spoutdesigned with cascading cones that prevent the product from dropping straight down through thespout. As mentioned earlier, free-falling product can promote dust entrainment and liberationinto the ambient air during the loading process. Cascading-type loading spouts are designed witha series of inclined cones that do not permit the product to free-fall through the loading spout.The goal is to minimize product velocity and induced airflow movement, by allowing theproduct to be transferred smoothly from one cone to the next. Originally designed to reducedegradation of the product, the cascading action was also thought to have the potential to lowerdust emissions by reducing product velocity and promoting mass flow [Maxwell 1999].Improved mass flow of the product allows the particles to maintain greater contact with oneanother and thus reduce the release of small dust particles into the air. Wind shrouds anddischarge skirts are the primary dust control devices utilized in these designs. Typically,cascading loading spouts are not equipped with dry dust collection systems. Within the loadingspout, cone size, spacing, and inclination are adjusted to accommodate different product flowrates. Also, since there is more contact between the product and the cones than found in freefallingspouts, abrasion-resistant liners are frequently utilized inside the cones.Figure 7.5. Cascade loading spout.Bulk Loading 193