EQUIPMENT


Pan Coating


Coating in pans is the eldest known processing option. By principle it is a top spray coating process, so that basically all physical aspects described in the section fluid bed spray coating also apply. There are however some differences in the methods of applying coating material.


Sugar Coating

This processing option is mainly used by the food industry and to a certain extent still from the pharmaceutical industry for the coating of tablets. The highly concentrated sugar solution is fed onto the tablet bed by means of a distribution rake and periodically interrupted to allow a further distribution by friction and a subsequent drying phase, such requiring relatively long processing times.


Filmcoating

This process is equally as efficient as the fluid bed spray coating process, having high process air volumes available.  Only the mixing of the tablets has to be enhanced by baffles with adjustable shapes for the many different tablet forms.  Furthermore,  jet nozzles are used instead of air atomized spray nozzles, because the coating material has to be applied in a narrow strip across the entire length of the rolling tablet bed. As the general particle size is usually larger than the substrate coated in fluid beds, spray droplets can also be larger, as higher mass dynamics avoid potential agglomeration.