On-Line Cleaning of Dryer Fabrics, 1996 Engineering Conference Proceedings

Most paper machines have elaborate systems to clean forming and press fabrics, but dryer fabrics are often neglected. Increasing use of recycled fiber and new, single fabric dryer designs have forced the papermaker to re-examine this strategy. More recycled fiber has made fabrics more apt to become dirty, while new dryer designs make their cleanliness and permeability more critical. “Shock” chemical treatments can cause improvement, but they are by nature expensive, messy, and non-steady state. Conventional showering water volumes are too high to maintain dryer hood moisture balances and clean without fabric and sheet streaks. Research has indicated that shower energy is the determining factor for shower cleaning effectiveness. Further experiments have proven the effectiveness of very high pressure, low volume showers to maintain cleaning energy with very little water use. Such cleaning systems have been tested for cleaning effectiveness and fabric damage, both in the laboratory and paper mill, with very good results.