SIROLAN-LASERSCAN - A REVIEW OF ITS DEVELOPMENT, PERFORMANCE AND APPLICATION

The Sirolan-Laserscan instrument for the rapid measurement of fibre di ameter, both mean and distribution, has been in commercial use since 1 992. Information on its performance was provided to the International Wool Textile Organisation over the nineteen month period leading to ra tification of the test method covering its operation as a full IWTO Te st Method at the 1993 Nice meeting of the IWTO. The development of the Sirolan-Laserscan followed a feasibility study on upgrading the Fibre Diameter Analyser (FDA). This study concluded that discrimination err ors and operator effects introduced the possibility of bias in the dia meter distribution produced by an FDA. The decision was subsequently t aken to develop the Sirolan-Laserscan rather than to modify the FDA. T he Sirolan-Laserscan measures the diameter of individual fibre snippet s that intercept a laser beam; the change in the detected light from t he laser is related to the diameter of a snippet. The discrimination s ystem in the Sirolan-Laserscan rejects measurements that include dust, fibre fragments, multiple fibres, or snippets that do not fully span the beam. The accuracy of the Sirolan-Laserscan with respect to Airflo w and Projection Microscope techniques, has been demonstrated by round trials which have also established the precision of Sirolan-Laserscan measurements on tops and scoured coresamples. For mean diameter these are +/-0.2 mu m and +/-0.4 mu m for tops and +/-0.4 mu m and +/-0.7 m u m for coresamples, with the higher values for each type of material applying to wools with mean diameters greater than or equal to 26 mu m . The Sirolan-Laserscan's reliability and performance robustness have also been demonstrated in a series of trials that examined the stabili ty and repeatability of the measurement system, operational factors su ch as temperature and the water content of the transport fluid, and fi bre issues such as snippet length, ellipticity and medullation. Fast a nd accurate diameter measurements for both mean and distribution, as p rovided by Sirolan-Laserscan instruments, have found application in sp inning and combing mills, testing laboratories, and research and educa tional institutions.