ISO 3968:2017
Filter Pressure Drop Estimator
Estimate filter element differential pressure at operating conditions by proportional scaling from a datasheet reference point. Applies Darcy's Law for laminar flow through filter media. Valid when Reynolds number in the media is below 0.1 (Darcy regime).
FORMULA
VARIABLES
ASSUMPTIONS
· Flow through the filter media is in the laminar (Darcy) regime — no inertial effects.
· Filter media is clean (new or recently serviced) with negligible captured particle loading.
· Fluid is Newtonian and viscosity is uniform across the filter element.
· Reference data is taken from the manufacturer's ISO 3968 test report at the stated conditions.
LIMITATIONS
· Proportional scaling fails at high Reynolds numbers where inertial resistance becomes significant.
· This tool does not account for dirt loading — captured particles increase ΔP over service life.
· Accurate ΔP-Q curves require ISO 3968 testing; this tool provides estimates only.
· Non-Newtonian fluids (grease, some synthetics) invalidate the linear viscosity scaling.
CALCULATOR
RELATED STANDARDS
iso-16889 →RELATED TECHNOLOGIES
MACROCORE™
SYNTRAX™
VALIDATION: Verified against published ΔP-Q curves: external manufacturer HF6 hydraulic filter series at 3 viscosity points (ISO 3968 test reports); Parker Hannifin 60HF hydraulic filter datasheet. · SOURCE: ISO 3968:2017 · STATUS: VALIDATED