Sizing

Usually, there is a well defined requirement to the agglomerate size distribution of the final powder. It is therefore necessary to sift the powder. This is done is a sieve with two different net sizes placed above each other. Thus it is possible to remove any agglomerates/lumps considered to be too big in the final product. This oversize fraction may be milled and returned to the process. Powder passing through the upper net may be further fractionated on the lower net into a main fraction and a fines fraction consisting of single particles and agglomerates being too small. This fines fraction is together with the cyclone fraction from the Vibro-Fluidizer® recycled back to the process.

The actual powder feeding system consists of a silo and a screw conveyor with variable speed. The powder is by means of a rotary blow-through valve fed into a high-pressure air line conveying the powder to the agglomerating module.

It is usually a requirement to most rewet installations that they are product flexible. Therefore, both droplet and surface agglomeration methods are often installed in the same plant. The rotating cone may also easily be incorporated in the plant thus giving the possibility of agglomerating any milk based product. Lecithination may naturally also be applied to this process, if cold water fat-containing products are aimed at. In Figure 1 a flow sheet or a rewet plant Niro design is shown, with the possibility of all above mentioned agglomeration systems.

Figure 1. Niro Multi-Purpose Rewet Agglomeration Plant