Measuring concentration in paper sizing process

In papermaking, sizing provides paper a desired degree of resistance to water or other fluids and increases surface strength. Vaisala K-PATENTS® Process Refractometers are used for precise concentration measurement and control of sizing liquids in the internal sizing, surface sizing and coating processes. 

The control applications are in:

• Sizing liquid cooking where the cooked starch, CMC or PVA is diluted with water to the desired concentration before storage.
• Size press or blade coater where concentration levels vary in the size press circulation system. The paper absorbs more water than sizing material and this changes the concentration of the liquid to the recirculation line. Therefore, water must be added into the circulation to maintain the dilution levels.

Accurate concentration measurement ensures tight concentration specifications of the sizing liquids and helps to stabilize sizing conditions and paper quality.