Top-Spray or Fluid Bed Agglomeration
The fluid bed granulation process, also known as top-spray agglomeration, can be an ideal approach for pharmaceuticals, as well as cleaning agents, food and beverage powders, and cosmetics—without compromising on the initial powders' properties.
This method involves using an air stream to suspend even the tiniest particulates in a fluidized bed. Liquid is sprayed from the top down, wetting particles so they stick together when they collide. As they adhere, they can form granules with a variety of specific properties, such as size distribution and density, to meet your specifications.
Dry-Stage and Wet-Stage Agglomeration
Depending upon the characteristics of your particles, you may require dry-stage or wet-stage fluid bed agglomeration or granulation. While dry-stage granulation is more common, wet-stage agglomeration allows for denser products.
In dry-stage granulation, particles require only a slight wetting to become tacky and stick to one another. The granulating solution is applied at a rate less than or equal to the evaporation rate, keeping the particles relatively dry throughout the process.
In wet-stage granulation, the particles require significant wetting before they become tacky enough to stick to each other. The granulating solution is applied at a rate higher than the evaporation rate until the particles build up enough moisture to granulate in the fluidized bed.
Agglomeration while drying is emerging as a cost- and time-effective alternative to traditional granulation methods, precluding the need for multiple processes. This patent-pending technology, Pulse Width Modulation, applies an intermittent electrostatic charge to the feed.
When voltage is precisely applied to the spray droplet as it is being atomized, some particles readily form an outer shell while others develop a shell gradually, resulting in a wet or tacky particle. As these two types of particles collide, they bond to form an agglomerated particle. This results in a free-flowing finished product with larger particles and fewer fines.