High precision VIB AirTech^{Plus 6} water moisturization system in Optiload twinline
in Kvarnsveden PM 12

1. INTRODUCTION

Development of water spray technology suitable for use together with new multinip calenders has been on-going for several years. One of the starting points of this development was on-machine SC-B paper making lines in Europe. There spray moistening was used relatively close to the calender but drop marks on paper were observed. This led to the development of spray nozzles and technology, which reduce the droplet size by half or even more.

First this VIB AirTech^{Plus 6} fine spray technology was introduced to more recent SC-B paper making lines, for example to UPM Steyrermühl PM 3. The first SC-A paper making line equipped with this fine spray technology was GNP Millinocket PM 11. In that production line, water sprays are used on the both sides of paper near an on-machine 10-roll OptiLoad multinip calender.

The development of water sprays after Millinocket PM 11 has been focused on better support of the web at the spraying zone in high speed machines, on improvements of air and mist handling in the spray area and on positioning of the water spray units inside the calender, not just in front of it.