Pulp with right properties is crucial for quality paper production. A combination of light and ultrasound can provide new opportunities to control quality of pulp reports processnet.se. Today exist several different techniques for analysis of pulp, but this new measurement technique developed at Lulea University of Technology, LTU, will help pulp industry to get even more detailed control of the process.
Since 2003 researcher Torbjörn Löfqvist, at EISLAB and the Department of Electrical Engineering, the method that broadly seeks to illuminate the masses with short laser pulses to spread in the mass and simultaneously generates ultrasound.
The technique is based on a combination of optical and ultrasonic measurements. The link between measured quantities and the mass fractions is established through Partial Least-Squares Regression (PLSR). The method is evaluated with experiments on unbleached softwood pulp for a total mass fraction of fibers and fines ranging from 0.6% to 0.54%. The results show that they are able to accurately predict both the fiber and fines mass fractions using the proposed technique. They also show that the performance is increased by combining the two techniques compared to using them by themselves.