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WORLD PULPPAPER 73 AVOIDS OVER CONTROL The SPK measurement was evaluated over a five month period in 2014. The advantages of a quick measurement update are shown in Figure 3 which clearly indicates that the SPK has avoided the two hour delay with the manual tests. At that point in time the operators were making downward machine speed adjustments for lower Kappa number but the data was two hours old. The same is true for the speed resumption period. Figure 4 shows how the manual and the online Kappa number variation sigma decreased over time as the pulp mill operators became more familiar with the measurement and how to control the cooking process. The variation of data in Figure 4 shows a consistent gap between manual tests and online measurements although both decreased as the pulp uniformity became better. That gap between manual and online tests implies that the extra human testing variability was inherent in the manual tests. Since the operators now use the online measurement the extra variability of the manual tests is no longer a factor. Lee confirms that the SPK numbers are an accurate tool for evaluating pulping process performance I have recently started using the K average and standard deviation of the SPK as the indication of how we are running compared to our yearly goals and I have discontinued using the manual test numbers he says. Recent data provided by Lee shows that the average online measurement sigmas for six months up to January 2016 were 2.63. That is better than 50 reduction from the initial trial numbers. Lee says The operators are making fewer and smaller changes to the liquor-to-wood ratios and that means more consistent pulp for the machines. A Green Bay Packaging report shows that liquor to wood ratio changes were reduced from 84month to 44month. Variability in the tests was causing us to over-control now we have cut the changes for better control adds Williamson. The board machine operators get a heads-up warning of changes well in advance and the swings are much less. As an indication of operator acceptance the machine tenders call to see Since the operators now use the online measurement the extra variability of the manual tests is no longer a factor Figure 2. Single Point Kappa SPK Analyser installed Figure 3. The SPK analyser eliminates the two hour delay with manual testing and updates the reading twelve times per hour. Machine speed changes are now based on current data.