The FAUDI Aviation DPGUARD is a fully automated touchscreen operated calculator to give out the corrected differential pressure across the filter elements (monitor filters or coalescers) in mobile or fixed filter vessels being operated at less than maximum rated flow. The DPGUARD automatically calculates the condition of the filter elements inside the vessel using the signal inputs of flow rate and differential pressure across the elements. It monitors the changing condition of the elements and provides a history so that element change times can be anticipated and abnormal conditions could be detected. The system is based upon the related joint standards as described in EI 1581, EI 1583, EI 1590 and EI 1596.