When machines at pulp and paper mills have wet-end runnability issues such as web breaks and non-uniform profiles, this often causes quality and runnability issues at the machine itself and at end-user.
To understand the root causes of these problems, it is sometimes necessary to look at the wet-end moisture profile uniformity. To that end, FPInnovations has developed a technique using a portable infra-red (IR) moisture sensor that measures and analyzes moisture profile in cross-direction content at the wet-end of paper, board, or pulp machines.
The image shows a setup of the moisture sensor at an open draw of a pulp drying machine. The moisture sensor is usually installed at a distance of 3 cm from the web surface.
Moisture is usually measured after the press section, at the open draw between press and dryer section. When access, even if limited, is possible due to machine configuration, then the sensor head can be mounted on a travelling cart or on a bracket.
Benefits of IR moisture sensor:
- Evaluate the real moisture content of paper, board, or pulp at different locations on machine
- Evaluate the moisture profile uniformity in cross-machine direction, and relate it to the dry-end moisture profile
- Troubleshoot wet-end break issues on machine, by analyzing where the non-uniform moisture profiles could come from
- Solve quality issues such as baggy edges, moisture streaks, corrugations and others by analyzing the drying history on machine, from the wet-end to the dry-end
The reduction in web breaks on pulp or paper machines could lead to significant cost savings from reduced loss of paper and/or improved productivity (>$0.5 M/year).