Contaminant Measurement
Quality control in pulp mills requires measuring the number of un-defibrated fiber bundles or wood fragments present in a pulp sample. A high shive count indicates incomplete cooking or refining, which can lead to aesthetic and structural issues in the finished paperboard. These large, rigid particles do not conform well during sheet forming and create weak spots in the web.
Mills use screen plates to filter out these bundles and maintain pulp purity. Automated optical analyzers measure this property continuously by passing diluted pulp through a light source and counting the dark specks.
Pulping Efficiency
The digesting and refining processes must break down wood chips into individual fibers. If the chemical charge is too low or the mechanical refining is insufficient, the shive count will rise. This value indicates the effectiveness of the pulping and bleaching operations.
Monitoring this property allows operators to optimize chemical consumption and energy use.
Sheet Defects
When these fiber bundles end up in the paper machine, they create bumps on the sheet surface that interfere with printing ink transfer. This defect can lead to ink voids or web breaks on high-speed presses. Keeping this count low is necessary to produce smooth, high-grade printing papers.
