Patent ID: 8840790

Claim:
A method of controlling fouling of a membrane during a fluid filtering process, comprising: accepting a selected filtrate flow rate; selecting a maximum transmembrane pressure; predicting an estimated procedure end time to separate at least a portion of a filtrate fluid from a bulk fluid; calculating a control point corresponding to the maximum transmembrane pressure and the estimated procedure end time; flowing the bulk fluid past the membrane; achieving the selected filtrate flow rate through the membrane; determining a transmembrane pressure and time elapsed when the selected filtrate flow rate is achieved; determining an acceptable fouling rate, as defined by a slope of a plot of a current transmembrane pressure and the control point, and a slope of a plot of periodically-measured transmembrane pressures versus time; comparing the two slopes to determine an acceptable rate of change with time of the transmembrane pressure; and adjusting the filtrate flow rate based on the determined acceptable rate of change with time of the transmembrane pressure to cause the plot of periodically-measured transmembrane pressures versus time to approximate the plot of the acceptable fouling rate.