Abstract: A calender stack having a plurality of hard and soft calender rolls for use in calendering a coated or uncoated paper web which comprises employing a plurality of soft rolls exhibiting at least two distinct levels of hardness and arranging the rolls in a calender such that the level of hardness is progressively harder in the direction of travel of the coated paper web.

Abstract: A method for determining statistical characteristics of a measurable property includes the initial step of monitoring the property and generating an electrical signal, the magnitude of which is a representative measure of the property. The electrical signal is passed through a high pass filter to eliminate low frequency noise which would otherwise tend to affect artificially extreme values of the signal. The maxima of the filtered signal is then determined within defined time intervals and extreme value statistical analysis is applied to the maxima of the filtered electrical signal to determine statistical characteristics of the measurable property. This method and apparatus for performing the method may be favorably applied to monitoring weight basis of sheet material, such as paper, as the material is being produced.

Abstract: A drying system and method for removing volatile liquid from a liquid bearing web of material by evaporation includes means for moving the liquid bearing web of material through a drying station and heating means, positioned at the drying station, for applying evaporation energy to the liquid bearing web of material to effect evaporation of the volatile liquid from the web. Electrostatic means is provided for subjecting the web of material to a static electrical field at the drying station, whereby the evaporation of volatile liquid from the web is enhanced. Evaporation energy may be applied to the liquid bearing web by bringing a heated surface in contact with the web or by irradiating the web with infrared energy. Alternatively, evaporation energy may be applied to the liquid bearing web by directing heated air against the web.