PAPER QUALITY CONTROLS BY UTILIZING NEW CONSISTENCY MEASUREMENT CAPABILITIES - BOTH OPTICAL AND MICROWAVE TECHNIQUES PROVIDE GOOD RESULTS

New optical and microwave based measuring methods make it possible to control consistency more accurately than before. This paper presents n ew integrated control applications for paper machine wet end and stock preparation. Thick stock consistency is used in feedforward control, headbox consistency is controlled to stabilize short circulation and w hite-water consistency is controlled using retention aid. The controls were tested on production scale paper machines, and considerable impr ovement in paper quality could be found.