Method of determining filter pluggage by measuring pressures
AssigneeE. I. Du Pont de Nemours and Company
InventorsKenneth S. Freund, Elizabeth L. Frisbie, Robert E. Wojcik
Life of this patent
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Abstract
A method to determine differential filter pressure caused by filter pluggage in a high pressure liquid system operated by a computer-operated control valve without the need for a pressure sensor coupled to the filter by corerlating the percent the control valve is open with the differential pressure of the filter. A signal is provided when the percentage of time the control valve is open exceeds a predetermined time and the filter is replaced in response to the signal.
Claims2
A method for determining a pressure drop across a filter located between a jet and a pressure control valve that is connected to a pressurized liquid manifold with the aid of a computer to calculate percent openness of the valve and determine when to replace the filter, said method comprising:
- a) obtaining a data set of manifold pressure, jet pressure set point, and the correlation between percent open and a corresponding flow factor of the pressure control valve;
- b) providing the computer with a data base that includes the data set obtained in step (a);
- c) programming the computer to calculate percentage openness of the control valve according to the following relationship:
- ##EQU2## wherein K.sub.1 and K.sub.2 are constants based on valve manufacturer provided characteristic plot of openness of the valve and resulting flow factor, GPM=gallons per minute, manifold psi=manifold pressure, filter psi=pressure drop across the filter and jet psi jet set point pressure signaling when said % valve the openness exceeds a predetermined value;
- and replacing said filter in response to said signaling.
Dependencies are inferred from the claim text.