Blade coating with free jet applicator: Modeling and experiments

This work had three main objectives. The first one was to make a sufficiently accurate macroscopic model for blade coating with the free jet applicator unit. The model takes into account viscous forces with lubrication approximation. Inertial forces before the blade are calculated from the momentum balance. Filter cake growth and inertial forces affecting this growth are included in the model. Compression of the web and roll cover can be taken into account by using a spring model. The second objective was to measure as many model parameters as possible to reduce the number of adjustable parameters. All input parameters for the model except the elastic moduli were experimentally evaluated. The third objective was to verify the model by comparing calculated and measured blade pressures at the pilot coater. This required that the tube force transfer curve was determined. The model predicted experimental blade pressures fairly well especially at higher speeds (2000 m/min). However, contrary to our presumptions and the model predictions the influence of the mass flow from the jet i.e. the influence of impulse force on coat weight was insignificant.