Patent ID: 6069688
Filing Date: 2000-05-30
Classification: D21C,G01N

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, said method arranged to be used with an apparatus that includes a light source for generating light energy in a plurality of wavelengths, an optics module connected to said light source for injecting said light energy into said pulp and subsequently collecting said light energy reflected by said pulp from a first and a second location, a feedback device connected to said light source and associated with said optics module arranged to return said light energy from a location proximate said optics module and a light analyzer array connected to said optics module arranged to receive said reflected light energy collected by said optics module from said first and second locations and said light energy returned by said feedback device, said light analyzer array arranged to determine the intensity of each wavelength of light energy received from each of said first and second locations and from said feedback device and to generate a plurality of first analog output signals indicative of the intensity of each wavelength received from said first location, a plurality of second analog output signals indicative of the intensity of each wavelength received from said second location, and a plurality of feedback analog output signals indicative of the intensity of each wavelength received from said feedback device, said apparatus further including a measurement processing system, a configuration device connected to said measurement processing system for providing at least a first set and a second set of coefficient values and configuration data to said measurement processing system, and an output module connected to said measurement processing system and said process control system, the method comprising the steps of:retrieving said first set and said second set of coefficient values from said configuration device and storing said first and second set of coefficient values in first storage means;connecting said plurality of first analog output signals, said plurality of second analog output signals and said plurality of feedback analog output signals to said measurement processing system;converting said plurality of first analog output signals, said plurality of second analog output signals and said plurality of feedback analog output signals into a plurality of first digital output values, a plurality of second digital output values and a plurality of feedback digital output values respectively;normalizing said plurality of first digital output values and said second plurality of digital output values and generating a first set of normalized values and a second set of normalized values respectively;storing said first set and said second set of normalized values in second storage means;retrieving said first and second set of coefficient values from said first storage means, said first and second set of normalized values from said second storage means, and generating a Kappa number representation using said first and second set of coefficient values, said first and second set of normalized values and said configuration data;transferring said Kappa number representation to said output module; andconverting said Kappa number representation into a transmission form acceptable by said process control system, whereby said process control system controls the delignification of said papermaking pulp in accordance to the Kappa number representation.