Ship Unloader Metering Bin
This is an example of a ship unloading hopper designed specifically to handle difficult flowing cohesive materials such as gypsum and bauxite.
Why Conventional Ship Unloading Hoppers Suffer from Chronic Bridging and Inconsistent Discharge
Standard ship unloading hoppers use a pyramid hopper that converge to a small opening that use a slide gate or clamshell to control discharge.
In summary, a pyramid hopper with a small opening is a poor choice of bin shape for handling difficult flowing cohesive materials such as gypsum or bauxite. First, the bin shape promotes a funnel flow discharge pattern. Funnel flow (which is a first-in, last-out discharge pattern) can be made to work with large bins with large discharge outlets. However, when the discharge outlet is small, gravity is insufficient to overcome the strength of the bulk solid at the discharge outlet, and hence chronic bridging and rat-holing is expected.
The solution to a reliable ship unloading hopper that is capable of handling difficult flowing cohesive materials has two parts. The first half of the solution is to use a plane flow hopper shape with a wide and long discharge opening. A plane flow hopper only converges in one plane at a time, and is vertical in the opposite plane. The plane flow hopper is the most conservative hopper shape. The purpose of using a conservative bin shape with a long and wide discharge outlet is to employ a geometry where if the Feeder were removed, the entire bin would self-empty with gravity in a mass flow or first-in, first-out discharge pattern.
The second half of the solution is to pair the plane flow hopper with a Kamengo Feeder. The value of the Kamengo Feeder is that it withdraws material evenly from its entire opening, which by definition is necessary to actually achieve a mass flow discharge pattern in the hopper, which is necessary when handling a difficult flowing, cohesive bulk solid.
To learn more about the physics of storage bin and feeder design as well as the root causes of bin plugging, please visit KamengoU.