The moisture content affects each phase of the production of pulp and paper products, from incoming raw materials such as wood chips and pulp to finished paper products, moisture content must be carefully monitored and managed at every stage of production.
Variations in moisture levels have the potential to negatively impact the efficiency of the drying process, increase processing time and disrupt commercial transactions based on product weights. Excessive moisture can result in increased product weight that increase shipping costs, whereas insufficient moisture may cause the product to fail to perform as intended. Comprehensive testing can provide pulp and paper manufacturers with an understanding of both the chemical composition and moisture content of raw materials and finished products.
To address moisture level consistency, accurate moisture measurement devices are now available in portable, point-and-measure models as well as fully integrated in-line analyzers. The selection of the most suitable device depends upon the specific application, process requirements and the conditions.
One consistent trend across the industry is the advancement in more user-friendly design. New modern moisture meters are highly intuitive, enabling untrained personnel to operate them. They measure moisture rapidly, often within seconds, allowing reduced test time and supporting faster, more responsive process control.
Moisture measurement devices
For pulp and paper applications, many processors rely on Near-Infrared (NIR) moisture meters to obtain rapid and reliable moisture readings during production and quality control.
NIR moisture meters follow the principle that water absorbs certain wavelengths of light.The meter reflects light off the sample, measures how much light has been absorbed and the result is automatically converted into a moisture content reading.
One example is the KJT130 Near Infrared Moisture Meter, which provides instant, non-contact moisture readings in a portable handheld format. Because the process is non-destructive, samples remain unaltered so they can be used for additional tests or put back into the product stream.
The user simply points the instrument at the product, and the moisture content is instantly shown on a digital display, with results accurate to .01% in a 0-100% measurement range. The instrument can be used to measure moisture levels in materials such as wood chips, wood fiber, pulp, paper and finished paper products.
For continuous monitoring, instruments such as the KB30 In-Line NIR Moisture Meter and the KJT700 Online MIR Composition Meter allow operators to monitor moisture and organic composition while materials move through production processes. These systems can measure parameters such as moisture content, BTU values and certain organic additives while materials travel on conveyors, pass through drop chutes or move through pneumatic transport systems.
Using Near Infrared (NIR) composition analyzers can provide almost instant, lab quality test results that make a significant difference during development and production.
Paper manufacturers can also monitor moisture levels using instruments such as the HK300 Instant Paper Moisture Meter. Designed specifically for measuring moisture in paper, kraft board and paperboard, the instrument provides instant readings without sample preparation. Factory calibrations are available for common paper products, and additional calibrations can be developed for specialized applications.
The HK300 can measure moisture levels in paper rolls, stacked sheets, linerboard, low moisture copy paper and kraft paper. With multiple probes available, the device can also perform single-sheet measurements and compression testing.
For wood applications, non-destructive moisture testing instruments such as the HM530 Wood Moisture Tester are recommended. This instrument uses high-frequency capacitance to measure the dielectric constant of the material and convert the reading into a moisture value. The system automatically compensates for variations in wood thickness and temperature. The HM530 can be used with a range of wood materials including plywood, particle board, fiberboard, hardwood, softwood, kiln-dried lumber and specialty wood products.
By simplifying the process, pulp and paper producers and converters can increase the quality of their products from raw input to processing to finished product distribution. The key is to cost-effectively conduct as much testing as required, with full confidence in the results, each and every time.