Papermaking furnish properties estimated by time-resolved spectroscopy

Papermaking furnish properties were studied in terms of the light scattering caused by fines and fibres. Scattering produces a retardation in the transit time of laser pulses from a device developed for time-of-flight range finding. The transit time delay in pulp with a consistency of 0.5-0.8% was double or triple that in pure water and was proportional to the fines content. The repeatability error of the measurement system was demonstrated to be less than 10% of the retardation caused by the fines. Both chemical pulp and TMP containing wood fines or china clay were used in tests.