Content area
Full Text
These rules of thumb help ensure reliable flow of solids in applications where mechanical conveyors are not feasible
The need to transfer bulk-solids materials from the outlet of a bin or from a conveyor, to a process, truck, or another bin is ubiquitous throughout the chemical process industries (CPI). Transferring material using equipment designed to mechanically convey chemicals works quite well, especially for long distances; however, for short distances, it can be prohibitively expensive and maintenance-intensive.
As an alternative, chutes are used instead of expensive conveyors to transfer solids short distances. Merriam Webster describes a chute as: "an inclined plane, sloping channel, or passage down or through which things may pass." A chute is simply a pipe or trough that is sized properly and at the correct slope angle to ensure sliding of the material to be transferred.
Below is a list of do's and don'ts to ensure reliable chute flow. A chute test can be run in the laboratory to determine the minimum chute angle required to ensure reliable flow through your chutes. As with all testing, simulation of actual handling conditions is critical. Conditions such as moisture, particle size, temperature, representative-chute surface, all come into to play when evaluating your chute designs.
Don't: Drop your material from high heights. Chutes are different from hoppers when handling chemicals and other bulk solids. When a material flows in a hopper, it is under constant pressure acting normal to the hopper walls. In a chute, solids undergo impact such as falling from a conveyor, mixer or bin onto the chute. This drop causes the product to impact the chute creating the potential...