Abstract: 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 output values are then normalized in accordance to a normalization algorithm and stored with a time marker. The normalized values are used along with previously-stored coefficient values that represent a model of the delignification process for any particular point in time, and in accordance to the time marker and configuration data from a configuration computer, a Kappa number representation is calculated in accordance to a Kappa number-generating algorithm.

Abstract: 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 light collector located far from the point of injection. The light energy collected by each light collector is conveyed to a respective light analyzer associated with each light collector. Each light analyzer divides the detected light into distinct spectral wavelengths and generates output signals representing the intensity of light energy received in each wavelength. A feedback arrangement conducts the light energy emitted by the source to a location proximate the point of injection and then to a light analyzer.

Abstract: 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 representing the intensity of selected wavelengths of light energy received by the light collectors. An included feedback arrangement conducts the light energy emitted by the light source to a location proximate the point of injection and then to an associated light analyzer that generates analog output signals representing the intensity of the light energy emitted by the light source in selected wavelengths.