Important Terms from A to Z
The term dry bulk is used to describe all materials that are pourable/flowable in larger quantities due to their shape. These goods are also called simply “bulk cargo”, “dry bulk cargo” or “dry bulk trades.” According to the United Nations definition, they include all goods that, due to their uniform physical properties, are suitable for bulk cargo handling and transportation. These are vast delivery volumes of goods that are usually not intended for end-consumers, but for traders and downstream companies.
Dry bulk includes building materials such as sand, gravel and cement, fuels such as coal, petcoke, sulfur and pellets, foods such as cereals, salt and flour, as well as pigments, granules and ore. It is usually stored in silos, bunkers, or outside if not weather-sensitive, and can be distinguished into two groups: non-cohesive (free-flowing) bulk, and cohesive bulk.
Bulk mechanics is the study of a granular material’s transport and handling behavior due to its composition and physical characteristics. The properties of dry bulk consist of its particle size, particle size distribution, material density, shape or friction angle, chemical composition, moisture content and temperature. Once a certain activation energy is exceeded, dry bulk can behave like fluid. The most important parameter for its movement behavior is its flowability.
The “pourability” or "flow" is defined in the DIN standards and refers to the mode of transport in which the bulk material can move freely in a container without otherwise being secured. In addition, a distinction is made between transfer of material via uninterrupted flow, and single transfer methods. The former method involves transfer equipment such as vacuum hoses or pipes, conveyor belts, rotating bucket wheels, and vertical screws, whereas the transfer of cohesive, non-pourable bulk materials is much more demanding and is usually carried out using a tiltable containment.
Status: December 2015
All information subject to change. Errors and omissions excepted.