High precision VIB AirTechPlus 6 water moisturization system in Optiload twinline
in Kvarnsveden PM 12
|
With the Finite Element Method (FEM) is was possible to optimize further the nozzle characteristic and air flow, to stabilize the spray cone even on high web speeds over 25 - 35 m/sec. (1500 - 2000 m/min). In figure 2 is shown the Phase Doppler Particle analysis of the particles in the spray pattern.  Figure 2. Laser Doppler measurement and FEM calculation of spray nozzle
The control capabilities for each nozzle were improved by precise calibration of the 6-bit digital block. Today the flow of each controlled spray nozzle has bit accuracy of 0.05 l/h. Vacuum protected digital valve blocks and water supply lines assure, even under on/off conditions for an off-line OptiLoad, a droplet free moisture application with finest linear control. The shut off function of the digital valve blocks allows splicing of a new reel of paper. |
The absolute linear flow characteristics of the 6-bit technology controls the moisture with zero hysteresis in MD and CD for in calender remoisturization. The most recent start-up of high precision VIB AirTechPlus 6 water moisturization system is at Stora Enso Kvarnsveden PM 12 and happened at the end of 2005. Water moisturization units are used in the two off-line OptiLoad TwinLine calenders. This start-up has been extremely successful and VIB AirTechPlus 6 water spray system has been in use since the first day of the production. To succeed in Kvarnsveden PM 12, a lot of pilot work had been done in R&D centers of VIB GmbH in Maintal, Germany and in pilot plants of CTC in Raisio, Finland and at Metso Paper Järvenpää, Finland. The main benefits of using VIB AirTechPlus 6 fine spray technology together with OptiLoad TwinLine calender are extremely good moisture profiles both entering and exiting the calender, good reel hardness for high efficiency winding, low paper blackening, high paper surface density of paper and high paper gloss. These results are achieved both in the pilot machines and in production scale in Kvarnsveden PM 12. Page |
