Moisture Quantification
The primary reference method for determining the water content in paper involves calculating the difference in sample mass before and after complete thermal desiccation. This laboratory measurement, known as gravimetric moisture, provides the absolute baseline used to calibrate online infrared sensors. It remains the global standard.
Testing Procedure
Technicians weigh the moist paper sample immediately upon collection to prevent any evaporation into the ambient room air. The sample is then placed in a ventilated oven maintained at one hundred and five degrees Celsius until it reaches a constant dry weight. Comparing the initial wet mass to the final dry mass allows for the calculation of the percentage water content.
This laboratory method requires high-precision analytical balances and careful sample handling to avoid moisture absorption from the surrounding air during the final weighing.
Calibration Utility
Papermaking machines rely on the results of routine laboratory analyses to verify the accuracy of their continuous drying control systems. These gravimetric moisture checks prevent downstream conversion issues. Incorrect moisture readings can lead to serious defects such as paper curling or poor ink absorption during printing.
Consistent calibration checks ensure that the delivered paper meets the strict moisture limits specified in purchasing agreements.
