Powders dosing for plastics

The powder colourants are stored in transparent tanks which base supports the variable speed dosing screw: the overall structure is tunnel shaped in modules, each one sporting 8 tanks on both sides while in centerlane the digital scale moves on its robotized carriage. Free access is then granted on both sides of the tunnel for maintenance, while one side is dedicated for independent vacuum powder refill through absolute filters: slide mounted, each tank can be extracted without lifters, and any active part is at reach. Reproducible dispenses require constant humidity, therefore each tank has dry air fluidizing beds activated by powder content; the airtight screw outlet is aimed upwards in order to pour the granules exactly in centerline of final tub, and the adaptive height of the scale allow the use of different sizes and capacity tubs where recognized by the mixer. The workshop health is granted by individual air suction either from dispensing screws and from powder tanks probes, then a wet cell scrubber exhausts to atmosphere.