Predicting the Pressure Drops across Cellulose Acetate Filters

A theoretical model of the pressure drop across a fibrous cigarette filter is derived. The pressure drop is expressed as a function of the filter dimensions, the fiber tow characteristics, the filter weight, the fluid flow rate, and a filter fiber factor. The fiber factor is affected by the distribution of the fibers within the filter, the relative orientations of the fibers, and their cross-sectional shapes. The model allows one to accurately calculate the influences of these variables on the filter pressure drop. Additionally, it can be used to predict capability curves and select an optimum cellulose acetate tow for a given filter pressure drop.