Patent ID: 7922914
Filing Date: 2011-04-12
Classification: B01D

Abstract:
1. A method of monitoring characteristics in a fluid flow path having a filter that is actively filtering fluid in the path, the method comprising the steps of: measuring ΔP (pressure drop) in the fluid as it flows through the active filter; normalizing the measured ΔP to a state having predetermined reference conditions; comparing the measured ΔP at the normalized state to a ΔP of a hypothetical reference filter for which there exists a known correlation between ΔP and contaminant removal from fluid under the predetermined reference conditions as a function of at least one of time, contaminant load and volume of fluid filtered; wherein the contaminant removal from fluid is defined by the time-weighted ratio of the number concentration of particles larger than a certain size upstream of the hypothetical reference filter to the number concentration of particles larger than the same size downstream of the hypothetical reference filter under a standardized laboratory filter test; and estimating contaminant removal from fluid filtered by the active filter as a function of at least one of time and contaminant load and volume of fluid filtered for the active filter wherein contaminant removal from fluid filtered by the active filter is estimated based on the known correlation between ΔP and contaminant removal from fluid under the predetermined reference conditions for the hypothetical reference filter.