Wet Bulk Materials
When manufacturers refer to bulk material handling equipment, they are generally referring to equipment that is made to handle dry bulk materials. Some of these manufacturers may design and build equipment for wet bulk material handling, but it is a less common engineering field. The wet contents of bulk material may not be added until the product is mixed and ready to be sold, so wet bulk material usually has a lot less to do with the complete process of a bulk handling system. However, there are some applications where materials are wet from the start. This of course leads to entirely different flow issues and the need for special equipment.
One innovative tool that is used for mixing wet materials is a shaftless screw-feeding mixer. A screw-blade turns material horizontally or vertically in a tank, but the blade is not centered on a drive shaft. Instead, the blade is built out of high tensile steel that is shaped in a spiral pattern. The end of the screw feeder is attached directly to the mixing motor. The absence of the central drive shaft prevents material from sticking and slowing down the blades or obstructing the material flow. This way the mixing quality remains consistent and less material is wasted.
Pulp, a wet byproduct of wood, is processed and handled in very large volumes at industrial facilities like mills and paper plants. In an application like pulp handling, all mixers, conveyors and storage tanks would need to be capable of providing a smooth flow. They also need to be accessible for cleaning because inevitably some material will get stuck on the side walls. Pneumatic conveying is the method of choice for transportation of bulk materials in a wet handling system because they are fully enclosed and easier to flush out between uses. Overflow in an unenclosed conveyor could create material waste and damage to surrounding equipment.