Fluid bed drying is a very effective method of solid particle drying. The surface of each individual particle is exposed for drying by suspending it in the air flow resulting in better heat transfer and shortened drying time. A homogeneous product temperature and a uniform drying of the product are achieved through the continuous and thorough mixing and controlling of the inlet and outlet drying air.
Accurate humidity monitoring of the drying air is needed to optimize the drying process. The conditions may vary with respect to humidity and temperature. In many drying processes, especially in the pharma industry, the outlet air may have high levels of evaporated solvents and chemicals. This requires very stable sensor technology. In most demanding cases, the outlet of the fluid bed is considered a hazardous area, requiring an intrinsically safe measurement instrument.