Removal of Air Using a Cleaner

Air has detrimental effects on the operation of the paper machine and on paper quality. Currently air and sand removal are conducted using separate equipment in the short circulation of most paper machines, but economic drivers are pushing the industry toward more simplified solutions. A cleaner equipped with an air and light reject removal option offers the possibility of simultaneous sand and air removal. The aim of this study was to estimate the feasibility of such an arrangement. The results showed that the air and light reject removal option increases the deaeration action of a cleaner. Low air content levels (below 0.2%) were obtained when the cleaner operated at typical headbox consistencies. The low levels match those of dedicated de-aeration equipment in some instances. Air removal was more challenging from furnishes with a high content of fines and surface-active substances. On the basis of the experiments, integration of air removal with an existing sand removal system could enable the abandonment of the vacuum tank in many instances.