A system for the continual, real-time, in-situ generation of a Kappa number used by a process control system to control the delignification of papermaking pulps that includes injecting broad-spectrum light energy from a light energy source into the pulp and collecting the resultant reflected light energy from a near-and a far-light collector. The reflected light energy collected by the light collectors is analyzed by associated near- and far-light analyzers that generate analog output signals re...

A method for the continual, real-time, in-situ generation of a Kappa number used by a process control system to control the delignification of papermaking pulps is disclosed. The method converts a plurality of analog output signals representing the intensities of spectral bands of light energy reflected by the pulp, and feedback analog output signals representing the intensities of spectral bands of light energy before they are injected into the pulp, into digital output values. The digital outp...

An apparatus is disclosed that develops output signals representing the degree of finished state of a processed medium during a process operation, such as the lignin content of wood pulp during delignification or, alternatively, the brightness during the bleaching process. Broad spectrum light energy from a light energy source is injected into the processed medium and the resultant reflected light energy is collected from a first light collector located near the point of injection and a second l...