Smart filter monitor

A method for filtering a fluid, the method comprising:

• filtering a fluid with a first fluid filter;
• measuring a viscosity-indicating property of the fluid;
• reading from a memory device a differential pressure set point corresponding to the measured viscosity-indicating property;
• measuring a differential pressure across the first fluid filter;
• comparing the differential pressure to the differential pressure set point;
• and
• signaling if the differential pressure exceeds the differential pressure set point.

A system for filtering a fluid, the system comprising:

• a filter housing;
• a filter medium within the filter housing;
• a filter input line attached to the filter housing on one side of the filter medium for carrying unfiltered fluid to the filter housing;
• a filter output line attached to the filter housing on the side of the filter medium opposite the filter input line for carrying filtered fluid out of the filter housing;
• a differential pressure sensor connected to the filter input line and to the filter output line to measure a pressure difference across the filter housing;
• a bypass valve connected to the filter input line and to the filter output line to permit passage of unfiltered fluid from the filter input line to the filter output line once the pressure difference across the filter housing exceeds a bypass valve pressure;
• a viscosity-indicating property sensor connected to at least one of the filter input line and the filter output line to measure a viscosity-indicating property of the fluid;
• and
• a filter monitor in communication with the differential pressure sensor and in communication with the viscosity-indicating property sensor to permit the filter monitor to issue an operator alert when the pressure difference across the filter exceeds a differential pressure set point, wherein the differential pressure set point is a function of the viscosity-indicating property of the fluid.