System development for monitoring the production process of freeze-dried samples: A simple and low-cost approach

The data acquisition from the freeze-drying process is important for obtaining freeze-dried samples with the desired final moisture content under various operating conditions. The current study presents in extensive detail a simple and low-cost methodology for the implementation of a data acquisition system in a laboratory-scale freeze dryer. The results showed that the use of higher drying temperatures (40?C) increased the errors involved in the measurements of the mass of material; nevertheless, the application of correction blank curves statistically significantly reduced those errors. In general, the system developed provided precise and accurate measurements of the temporal changes in the sample mass and temperature, and chamber pressure variations, allowing monitoring of the production process of freeze-dried samples with low final moisture contents.