Fluidized bed spray coating

Solutions for coating small particles

Spray coating in a fluidized bed system produces an optimal surface coating for your product through even application of a film material. Depending on requirements, the product properties can be influenced and enhanced.

With this method, particles having different shapes and sizes are moved around in the fluidized bed and simultaneously sprayed with a liquid. The aqueous or organic solution evaporates and the solids it contains form the coating layer. A typical particle size is 100 micrometers up to 3 millimeters.

The casing can be used as a protective layer to increase shelf life or storage stability as well as to make the particles functional – for instance, to mask odors or tastes or to release specific active substances.

Spray coating can be performed – usually in batch processing – in all fluidized bed systems. For some coating applications, a continuous process is also available. The film material is applied as a solution, suspension or melt. Caution should be taken here that no liquid bridges form during application in order to avoid undesirable agglomeration.

When coating using a solution or a suspension, the liquid serves to transport the solids to the surface of the particles. When a melt is used for coating, in contrast, the coating material is one-hundred percent spreadable. Glatt technologies permit an optimal retention time of the particles in the coating zone. This assures outstanding coating qualities.

Coating can take place as top spray, tangential spray, bottom spray (Wurster process) or rotor process, depending from which direction the particles are being sprayed. These methods can all be performed in a single, modern fluidized bed system. Customized for your needs.