Application of Filter Flow Decay in a Continuous Monitoring System for Particulates in Deionized Water Supplies
Original Publication Date: 1985-Aug-01
Included in the Prior Art Database: 2005-Feb-19
By taking a continuous, small volume sample from the deionized (D.I.) water supply through a temperature, pressure, and flow measurement system containing a very fine, polycarbonate filter, periodic measurement of the "fouling" or "flow index" of the filter provides an on-line water quality measurement - an automatic particle monitor. Since the particles are retained on the filter, they may be analyzed after any unusual fouling is measured to provide clues to the source of the contamination. A flow decay index (FDI) of a filter can be calculated as follows: FDI = 100[1-(P0/PF)2(FF/F0)]r/(TF-T0) where: P0 = initial pressure. PF = final pressure, at the end of each measurement period. FF = final flow rate through the filter. F0 = initial flow rate. r = viscosity correction for temperature (see table below).