Benefits of a good silo design ?
Avoiding flow problems through adequate design.
To avoid problems in silos concerning flow, product ageing or decay, silo design is necessary. The design of a silo is based on the most economical case: gravity flow. Wall friction, internal friction and bridging properties determine the applicable hopper angle and opening diameter. In some cases through the design procedure it is found that a "simple" silo is not possible. This however saves a lot of work and costs. Well begun is half done.
To prevent flow problems in a silo, proper silo design is necessary. The most obvious (and the most economical) way of storing bulk solids is in a silo with gravity flow. In this case the silo consists of a cylindrical or rectangular part with a hopper.
The hopper lets the product converge to the opening. This simple fact is the direct cause of most problems, such as: unsteady flow, segregation, remaining product, ageing or decay of the product, shaking or quaking of the silo, flooding, or: flow does not occur at all.
For a lot of these problems equipment is available, or a solution can be found through "trial and error". Of course it is better to prevent these problems. This is possible when design is based on the measured properties of the product. The flow properties of the product must determine the geometry that is used. Even if an "ordinary" silo is not possible, this becomes apparent in the design process. In this way it does not have to be discovered in practise, after a lot of trouble and costs. In the design of a silo the major issues are: flow, bridging and feeder.
Problems with flow are connected to the occurring flow pattern. In a silo two important flow types can be distinguished: mass flow and funnel flow (ratholing, or core flow)