Enerquin pocket ventilation

Maintaining High Pocket Ventilator Efficiency

With increasing paper machine speeds and associated increasing drying performances required from existing paper machines, an efficient pocket ventilation system is a “must.” Although most conventional dryer sections usually are already equipped with adequate pocket ventilation systems, we find many machines with plugged “pocket ventilators” leading to unbalance hoods and saturated pockets, which defeat the purpose of a pocket ventilation system.

The plugging problems can be caused by improper maintenance of the pocket ventilation system filter bank or “stickies” coming from the drying of contaminated recycled paper processes. This problem is more than often encountered in processes involving “Corrugating Medium” or “Board” producing machines using lower-quality recycled paper with “stickies.”

“Stickies” are tacky substances contained in the paper pulp and process water systems of paper machines, and the main sources for “stickies” are recycled paper, waxes and adhesives. Macro “stickies” can be filtered out, but “micro stickies” will follow the pulp to the paper machine and might agglomerate and cause problematic deposits on surfaces such as the discharge opening (slots) of the pocket ventilators. Because of their hidden locations in the dryer section, it is practically impossible to access these pocket ventilators to clean the air supply slots adequately. For this reason, cleaning devices have been developed. They are now offered as an option for pocket ventilators destined to paper machines dealing with “stickies” or any other contamination problems causing potential plugging problems of the supply slots.

Typically, these cleaning devices use an internal spray nozzle directing a very high-pressure water jet at the slot. Conventional pocket ventilators cannot be retrofitted; you will generally need to replace your existing pocket ventilators with new ones to get this slot cleaning option. The cleaning procedure is straightforward and only requires a high-pressure power pump. Each nozzle must be cleaned independently while the machine is down, and only a few minutes are needed for each pocket ventilator. This cleaning can easily be integrated to the mill scheduled maintenance shutdowns. Adequately operated pocket ventilation system with clean pocket ventilators will significantly contribute to maintaining an optimized dryer section performance; it is also essential to ensure good hood operating conditions and prevent early hood deterioration.

Read more about Enerquin`s pocket ventilation: https://www.enerquin.com/runnability-solutions/pocket-ventilation/

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