Handling explosive dust — Part II
Part I of this article [Powder and Bulk Engineering, January 1987] reviewed the theoretical basis for understanding how dust explosions develop, discussed methods for identifying explosion hazards, and itemized ignition sources, preventive safety measures, and explosivity of some dusts. In general, dusts that pose the hazard of explosion fall into two categories: organics, such as carbon, carbohydrates and other foodstuffs, resins, and organic pigments; and metals, particularly less noble metals such as iron and aluminum dusts.
Part II presents background and application information on three equipment design approaches used to protect grinding and classifying systems from dust explosions. The approaches are pressure-and-shock-resistant and pressurized designs. Together, they are termed constructional protective measures because they focus on the way processing equipment is engineered rather than on ergonomic factors such as operator training. The article concludes by presenting examples of how constructional protective measures are being used to contain dust explosions in operations where organics [ in our examples, vitamin powder, sugar, lactose, and organic pigment] and metals [ aluminum powder] are processed.