Analytical Technique
Absolute determination of the water content in paper or pulp samples relies on the precise measurement of mass before and after the removal of volatiles. Gravimetric oven drying is the primary reference method used to calibrate electronic moisture meters and verify compliance with international standards. Measurement involves weighing a specimen, heating it at one hundred and five degrees Celsius until the weight becomes constant, and then weighing it again.
Mass calculation represents the total moisture lost during the heating cycle.
Operational Protocol
Success depends on the use of an analytical balance with a sensitivity of at least one milligram to capture the minute changes in the sample weight. Technicians place the specimens in a ventilated oven to allow the evaporated water to escape efficiently while preventing the charring of the organic fibers. Cooling the dried samples in a desiccator is necessary to prevent them from reabsorbing moisture from the air before the final weighing.
The duration of the drying cycle varies depending on the grammage and density of the board but typically lasts several hours. Every step must be recorded to ensure the repeatability of the results across different laboratory shifts.
Paper Mills
Paper mills use this data to adjust the steam pressure in the dryer section of the paper machine. Accurate moisture levels influence the calendering process and the final surface smoothness of the finished sheet. The method provides a definitive baseline for trade transactions involving bulk pulp shipments.
