Fluidized bed drying is a very efficient method of drying solid particles. The surface of each individual particle is exposed for drying by suspending it in airflow, resulting in better heat transfer and less drying time. The homogeneous temperature of the product and the uniform drying of the product are achieved through continuous and thorough mixing and control of the inlet and outlet drying air. Accurately monitoring the humidity of the drying air is necessary to optimize the drying process. Conditions may vary with respect to humidity and temperature. In many drying processes, especially in the pharmaceutical industry, the exhaust air can contain high levels of chemicals and evaporated solvents. This requires very stable sensor technology. In many demanding cases, the fluidized bed outlet is considered a hazardous area, requiring an intrinsically safe measuring instrument.


The Vaisala HUMICAP HMP3 Temperature and Humidity Probe is a general purpose probe designed for processes with moderate levels of humidity and temperature. The structure of the probe allows the sensor to be replaced in the field without tools, making it suitable for applications such as industrial HVAC systems, paint booths, clean rooms, environmental chambers, and applications where periodic recalibration is not sufficient for maintenance. HMP3 is part of the Indigo family and is compatible with Indigo500 and Indigo200 transmitters. You can use Vaisala Insight PC software for data visualization, easy probe setup, and self-calibration.

Insight PC software

For easy access to Indigo compatible probes Vaisala Insight PC software provides quick access to Indigo family measurement probe settings and data:

  • Smart humidity measurement probes HMP4 for high pressures, HMP5 for high temperatures, HMP7 for high humidity, HMP8 for pressurized processes, and HMP9 for rapidly changing environments
  • Smart carbon dioxide measurement probes GMP251 for% level data and GMP252 for ppm level data
  • Smart temperature measurement probe TMP1

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