Pulp consistency determined by a combination of optical and acoustical measurement techniques
2006 (English)In: Measurement science and technology, ISSN 0957-0233, E-ISSN 1361-6501, Vol. 17, no 4, 695-702 p.Article in journal (Refereed) Published
In this study, methods based on ultrasonic attenuation and optical time-of-flight measurements are used simultaneously in determining both the fibres and fines mass fractions, respectively, of a cellulose pulp fibre suspension. The optical measurements are done by a laser radar and the acoustical measurements are based on ultrasonic attenuation measurements in a pulse-echo set-up. Two kinds of long-fibre fractions are studied, thermo-mechanical pulp and chemical softwood pulp. Fibre and fines mass fraction ranges are 0.25–1.0% and 0–0.75%, respectively. The results show that the fibres are the predominant source for absorption and scattering of ultrasonic waves and are thus mainly contributing to the attenuation of ultrasound in the pulp. It is also found that the fines are the predominant source for optical scattering and fines are thus mainly contributing to the propagation delay of the light pulse in the laser radar set-up. By combining the ultrasonic attenuation and the optical time-of-flight measurements, it is shown that the mass fraction of fines and the mass fraction of fibres in a pulp sample could be determined, respectively.
Place, publisher, year, edition, pages
2006. Vol. 17, no 4, 695-702 p.
Research subject Industrial Electronics
IdentifiersURN: urn:nbn:se:ltu:diva-15756DOI: 10.1088/0957-0233/17/4/014Local ID: f4cfb0d0-c355-11db-9ea3-000ea68e967bOAI: oai:DiVA.org:ltu-15756DiVA: diva2:988731
Validerad; 2006; 20060913 (ysko)2016-09-292016-09-29Bibliographically approved