METHOD AND APPARATUS FOR ON-LINE MEASUREMENT OF PULP FIBRE SURFACE DEVELOPMENT

摘要

A method and apparatus for monitoring the fibre surface development of pulpsdue to the refining or beating of mechanical or chemical pulps; an opticalcell, fabricated with light-transparent windows, permits an incidentcollimated beam of light to pass through pulp stock flowing through the cell.The beam is transmitted through a polarizing filter prior to entering thecell, and through a second, crossed, polarizing filter, on exiting from thecell. The exit beam converges onto a photodetector. A gradual variation in themass of fibres of the pulp stock is established over a predetermined range andthis produces a change in the intensity of the transmitted light. As the lightintensity changes, it passes through a maximum value; this is accompanied by asimilar change in the photodetector electrical output signal. Thephotodetector signal is fed onto a signal processor which generates an outputcorresponding to the maximum photodetector output value, and this representsan index of the degree of fibre surface development.