Granule Processing | Batch Coating
In addition to the coating of powders we also offer the option of applying a coating 
to granules. The equipment designed to do this is the Hüttlin (1200 litres) and the Glatt (200 litres) fluid bed dryers. Both machines offer the possibility to apply effective and efficient coating to granules.
The application of a coating onto a granule requires a completely different approach and technique than applying a coating to a powder. A granular product behaves completely different to a powder, the surface to be coated is larger and with a granule one should consider that with too much friction the granule might fall apart or that fines will be created.
Download the print version for all possibilities of coating granules, or read here for further information.
Granule Processing Glatt | Hüttlin
The coating of granules requires a technique whereby a liquid or melt is applied to a granule after which the product can be dried or cooled. The reason for applying a coating is often to protect the granule against moisture, air, light, odour or flavour influences. A coating can also improve the flow- or dissolving characteristics of a product or ensure that an active ingredient in the product is released to the environment in a controlled way
The equipment we use for coating granules is the Hüttlin or the Glatt fluid bed batch dryer. In these machines a coating is applied while the granules are fluidized by air and swirl through the machine. Coating and drying (cooling) take place within the same machine. For spraying on the liquid several types of nozzles can be used and they can be located in various positions within the machine.
Small droplets in combination with a low viscosity ensure an even distribution of the coating over the product. An important requirement for coating is that the coating needs to be evenly distributed over the granule and that it is firmly in place and supplies a sustainable layer. The thickness of the coating can vary from a film like layer to a couple of millimetres.
The Glatt:
The Glatt is a batch fluid bed dryer with a capacity of about 200 litres. In this machine the liquid is added from the top of the machine. It is a smaller machine that, contrary to the Hüttlin, is also suitable for smaller campaigns.
It involves a very fast and effective process whereby the product (granule) is treated with the necessary care so that the chance of breaking down the granule is minimized.
The Hüttlin:
The Hüttlin also uses a fluid bed technique and offers considerable production flexibility. This machine offers the possibilities of film coating, coating with a hot melt and specific manipulations of the surface characteristics of the granule, pellets or tablets.
The machine we have has a capacity of about 1200 litres per batch. It is suitable to 
process large batches of high quality products to the right standards and offers the option of continuous uniform coating.The principal of fluid bed coating is that the granules are brought into motion by air streams and that during this swirling of the granules a coating is applied in combination with immediate drying (cooling) in the same machine. The Hüttlin offers a very high level of process control and that enable us to provide you with a continuous and consistent coating quality.
This machine further offers the option of applying a surface coating with a high level of integrity and offering the option to apply several different layers of coating. The process is suitable to coat non uniform, relatively fragile granules effectively.
None of these systems is suitable to any solvents other than water!!!