EFFECT OF BLOW BOXES ON EVAPORATION DURING CYLINDER CONTACT IN A PAPER MACHINE DRYER SECTION

In this paper an inexpensive configuration for a cylinder blow box (CBB) and its effect on the evaporation rate are described. The objective of this work was to determine the effect of the blow boxes on drying intensity on a paper machine. The pilot machine trials were simulated with a computer program. Based on these results two cases were simulated for a commercial paper machine with and without blow boxes on single cylinders. The results revealed that when using the blow boxes on single cylinders, the drying rate can be increased by up to 15%. The potential for using this kind of configuration is biggest at the beginning of a dryer section. A simple construction of blow boxes makes this technique useful especially in boosting the drying performance of older paper and board machines. The exhaust air from the boxes can be utilized in ventilation of dryer pockets.