Crill measurement in fibres

Crill are particles that are too small to be visible under an ordinary microscope but that are of great importance for fibre bonding in paper. A method for measuring crill, which was developed thirty years ago, is now being made available for industrial use. When measuring crill, you measure how "hairy" the fibres are. The more crill found on and around the fibres, the better binding ability they have, which in turn results in a stronger paper. In order to improve paper strength, it is therefore very useful to be able to measure the amount of crill in a pulp. With the aid of a crill sensor, it is possible to determine the amount refining required for optimizing the amount of crill in the pulp. This is also important from an economic point of view, since fibre refining is a very energy intensive process in paper production.

With the support of Forska & Väx (Research & Growth), a VINNOVA Programme, Innventia and Eurocon Analyzer, a measurement technology company, are developing a crill sensor for on-line application in pulp and paper mills. The aim is to make it possible to produce improved paper and pulp quality at lower energy costs.