First-in-first-out en

In the first-in, first-out (FIFO) logistics principle, the order in which goods are stored is identical to the order in which they are removed from storage. The product that was stored first is also the first to leave the system. This principle is particularly important for batch-critical, shelf-life-limited or quality-sensitive products, for example in the food, pharmaceutical or chemical industries.

In bulk material technology, FIFO refers to a flow pattern in which the bulk material that enters first is also discharged first. Ideally, all particles flow through the apparatus with a similar dwell time, so that there are no dead zones, short-circuit flows or back-mixing. This makes it easier to control the recipe, moisture content, temperature and active ingredient content along the product flow.

In practice, FIFO behaviour is supported by suitable geometries and process control. Examples of this are specially designed silos and bunkers with mass flow, vertical, tapered discharge zones, defined discharge devices (e.g. screws, dosing devices, tablet valves). In continuous mixing and drying processes, approximate FIFO behaviour helps to cleanly separate product transitions and clearly assign return samples.

When using silo mixers, FIFO is naturally not possible. Ideally (e.g. with the Gyraton® silo mixer), a homogeneous product is discharged regardless of when it was stored. This is a homogeneous mixture of all powders contained in the mixing silo.