Standard procedures for measuring paper moisture

Paper is an important part of the human ecosystem and paper products are still widely used all around the world in every country. Paper gets moisture from its environment and bad moisture affects the quality of the paper. During the production process of paper, it is crucial to know how much water is there in the product and for this purpose Moisture Meter is used by paper and wood pulp manufacturers.

The paper industry uses the following three methods to measure the moisture content of the paper:

Moisture Meter: Some Moisture Meters use electrical resistance and contact pins to measure the content of moisture in the paper pulp while others use special electrodes with rolling contact heads that allow the meter to get a reading of the moisture content of paper pulp during production. If the water content is high in paper pulp, the paper may fall apart and the high content of moisture can affect the efficiency of the instruments involved in the paper-making process.

Oven Dry Method: This is the most accurate method to check the moisture of paper and wood pulp and serves as the reference for any instrumental measurements. A paper sample after weighing is exposed to 221 degrees Fahrenheit oven. When the samples are weighed again after cooling, the gravimetric difference is calculated as ‘percent moisture’.

Moisture Saber: This is a common method of testing paper moisture in offset printing. The sword-like instrument is inserted into a stack of paper and it reads the paper’s RH to calculate moisture content. The degree of accuracy is acceptable for approximate measurements and paper mills often deploy this method to retain exact moisture data for the lots of paper they manufacture.

Measures to manage paper moisture content  
• Always prefer buying paper with the right moisture content whether offset or digital.
• Maintain stable moisture content through good paper handling within recommended guidelines.
• Use appropriate technology to ensure proper moisture levels by deploying moisture meters suited for paper, paperboard, corrugated boxes and wood pulp.
• Keep your current paper products at the optimum moisture content.
• The paper should get enough time to acclimatize to the environment’s temperature.
• The paper should not be stationed near a heating or cooling unit as these devices can interfere with the paper’s acclimatization process.
• During paper production, the packaged paper should be kept wrapped until the time it has to be processed.
• The use of vapor-proof wrappers is highly recommended during paper production as it helps the paper to remain fresh and tightly-knit, keeping the excess and unwanted moisture out of the final product.
Precautions for papers for digital printing

To ensure optimum performance for digital printing papers store paper in the original wrapper. Locate the press in a controlled temperature and humidity environment should be 65-75 degrees Fahrenheit. To eliminate temperature differences between the paper and the environment, acclimatize paper in its wrapper at print room conditions for 24 hours before printing.

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