Online estimation of the condensate load in dryer cylinders during section starting

A `condensate load´ (condensate in % of a totally full cylinder) over 1% accumulated inside the dryer cylinders of a paper machine is likely to produce a drive overload, eventually increasing the acceleration time or even producing an overload trip. This paper proposes and evaluates a confident online condensate estimation algorithm that gives updated information at preset speeds and when the transition to the rimming stage is detected. The experimental evaluation performed on a 500 mm diameter cylinder, with condensate load between 0.5% up to 25%, confirmed the ability of the algorithm to give accurate estimations within 0.5% intervals of condensate loads. The developed algorithm is a useful tool for the operators, allowing them to take the appropriate decisions according to the severity of the condensate accumulation detected.