AVA offers horizontal granulators that can be operated either in batch mode or continuously.
The powdery solid component is brought into intensive contact with a suitable liquid binding agent in the AVA mixer. The solid particles are interconnected with the aid of the binding agent (agglomerating), which results in the formation of spherical or crumb-like granules. By controlling the mixing intensity and the shear forces generated, differently sized agglomerates can be formed. The granules prepared in this way are of low or medium stability, depending on the binding agent strength. Subsequent granule drying, if required, should be carried out gently and through convective drying.
Using vacuum compact granulation, granules of high density (compaction), hardness, and stability can be produced. First, liquid binding agent is added to the powder until a slurry forms within the AVA mixer. Then the slurry is subjected to a vacuum to minimize air entrapment. Next, the slurry is granulated by means of contact drying or by adding more powder product under vacuum conditions. This method yields very compact, stable, and spherical granules.
Hot melt granulating is a special form of agglomeration granulating in which the solid itself acts as a binding agent. This is done by a partial liquefaction (melting) of the solid such that the particles can interconnect with one another. Energy is normally applied by means of the heatable mixer jacket. To solidify the granules, a cooling zone is set up downstream of the granulating process in the AVA mixer. In this zone stable, solid agglomerates are formed.
Micro granulating is a special form of agglomeration granulating, which produces very small agglomerates. This is done by a particularly intensive and uniform mixing of the binding agent with the solid. Very high shear forces limit the size of the agglomerates, thus resulting in a good distribution of the liquid component over the product surface without the need to apply large amounts of binding agent. The size of the agglomerates ranges from a few to several hundred microns. Most processes required for generating micro granules can be realized using AVA continuous ring layer mixers.