Filter Size Determination Using the "Vmax" Method with the FilterTec

Filter capacity measurements are a necessary requirement for any filtration scale-up. The sample solution under study is filtered through a small test filtration device at constant pressure, typically between 10–20 psi. The cumulative solution weight (or volume) exiting the dead-end filtration device is recorded as a function of time. If a linear plot of t/w versus t is obtained, where t represents time and w is the cumulative solution weight, a gradual "pore-plugging" model can be assumed. Vmax is the maximum volume of fluid that will pass through the filter before it is completely plugged. Vmax is determined by taking the inverse of the slope of plot t/w versus t.