The main purpose with dry granulation is to increase the density of the powder and increase the particle size to ensure a better flow of the distributed material, resulting in a better processing ability.
Granulation is the process in which powder particles are made to adhere to each other, resulting in larger, multi-particle entities, so called granules. In dry granulation, the process is performed without adding liquids, whereas wet granulation is performed by adding granulation fluid. In dry granulation, the powder is compressed by applying force, which will thereby give a larger unit, eg a tablet. To obtain the desired size of granules, the compaction process is followed by a milling step.
Dry granulation is most often used in the pharmaceutical industry for the manufacturing of tablets, but can also be used in, among other things, for manufacturing in the food industry or chemical industries.
Roller compaction is the best method to achieve the desired result by dry granulation. At PPS, we offer first-class equipment for dry granulation from Gerteis – a leading market leader in equipment for dry granulation, with a focus on roller compactors.
A Gerteis roller compactor typically consists of 3 major units:
- A feeding system, which conveys the powder to the compaction area between the rollers
- A compaction unit, where the powder is compacted between two counter rotating rolls by applying a force, to form ribbons or flakes
- A size reduction unit, for milling the ribbons into granules of the desired particle size
Roller compactors can be divided into two categories: One is equipped with a fixed gap, the other one with a floating gap. Machines from Gerteis are equipped with a variable distance (floating gap), which means that the rollers can change depending on how much powder gets through. The force applied to the powder is constant and the variable distance helps to ensure that fluctuations in granule size are reduced to a minimum.