抄録
Valmet has developed a unique calendering method based on the SymBeltTM shoe nip press technology. The method, called OptiDwell, is based on a long nip dwell time and the use of an elastic belt. OptiDwell improves bulk and surface uniformity of the web. The long dwell time together with low specific nip pressure will result in bulk preservation, with no compromises to the surface properties. The elastic belt, in turn, provides uniform paper gloss and first-grade printability. The OptiDwell method has been proven in board calendering, and promising results have been achieved in calendering newsprint and woodfree paper grades. Up to 5% raw material savings have been gained both in production and customer trials.
A pilot OptiDwell calender with production scale rolls is available for customer trials at the Valmet Technology Center in Jä-rvenpää Finland.
