Transferring powders, pellets, and granulated solids is a challenge for a wide range of industries. Not surprisingly, a great deal of innovation has gone into solutions for this challenge. There are many ways manufacturers, farmers, miners, and others have found to move their products. Here we'll talk about three of the most versatile.
Cleated belt conveyors - These are a modified version of the simple conveyors you've seen used for many other purposes. But most belt conveyors wouldn't be well suited for handling dry bulk solids. The obvious reason is that narrow, flat, moving surfaces have a hard time keeping powders and granules in place long enough to transfer them any distance -- at least without a few modifications. To meet this challenge, innovators like Cambelt International have added flexible side walls to hold material on the belt. Cleats or nubs on the surface of the belt keep the powders or granules from caking or rolling around on the surface.
These belts can be enclosed to keep from exposure to the environment if needed. Cleated belt conveyors can handle incredibly high volumes of material and are versatile enough to carry a wide variety of particle sizes and levels of moisture. But they may require more space than other options.
Screw conveyors - These machines, also called auger conveyors use a narrow spiral ramp around an extended shaft to push material along a tube or trough. As the shaft spins, material is pushed along the forward curve similar to how a drill forces wood out of a shaft it is creating. These systems are ideal for moving dry powders and granules where space is limited because they are very compact. However, at high inclines volume can be limited because material tends to pack in the tube. This can also happen along horizontal paths where any moisture is introduced. Slightly wet materials can begin to cake along the spiral path.
Pneumatic conveyors - These systems use pressurized air to move powders from one place to another. Airtight tubes are connected to vacuums at the destination end of the system, blowers at the source end, or a combination. The fluidity of pneumatic conveyors allows for multiple starting and ending points using multiple blowers and vacuums respectively. These systems can be contoured to fit into existing infrastructure because the air doesn't need to follow a rigid path. But these machines are only well suited for powders and very light weight granules. Also, any amount of moisture can render the system inoperable.
These three configurations account for nearly all handling of dry bulk solids for energy, food, construction, and manufacturing industries. They each have their strengths and weaknesses, but all are very efficient at what they do.