Patent ID: 6863919
Filing Date: 2005-03-08
Classification: D21F,D21G,D21H,F26B

Abstract:
1. A method for controlling a drying effect of an equipment layout used in making a coated web of paper or board, the equipment layout comprising at least one coater unit and a plurality of drying units, the method comprising: applying a liquid-containing coating to a surface of a web in the at least one coater unit; drying the web coated with the coating in the plurality of drying units by evaporating the liquid from the coated web until a moisture content of the web reaches a desired final moisture value; compiling, for each drying unit wherein moisture is evaporated from the web, an evaporation rate submodel suited for computing an amount of liquid removed by the respective drying unit, wherein at least one specific evaporation rate submodel is linked into a composite evaporation rate model; determining a needed overall evaporation effect to be performed by the equipment layout to achieve the desired final moisture value; determining, by employing the composite evaporation rate model, a needed moisture evaporation effect for each drying unit of the equipment layout having an evaporation rate submodel linked into the composite rate model to achieve the needed overall evaporation effect; and controlling the moisture evaporation rate for each drying unit of the equipment layout having an evaporation rate submodel linked into the composite rate model, the moisture evaporation rate being controlled in accordance with the determined needed moisture evaporation effect without measuring an actual amount of liquid removed by any individual drying unit of the equipment layout while such drying unit is drying the web.