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SCHEMATICCURRENT · v1.0.0DIAG-MULTIPASS-TEST

ISO 16889 Multi-Pass Filter Test Circuit

Documents the standardised test circuit for determining filter efficiency (Beta ratio) and dirt-holding capacity under ISO 16889. The multi-pass method recirculates test fluid with injected ISO medium test dust to achieve steady-state upstream particle concentration, enabling reproducible efficiency measurement across particle size ranges.

ISO 16889 Multi-Pass Filter Test CircuitThe ISO 16889 multi-pass test circuit for measuring filter efficiency (Beta ratio). Test fluid circulates from the reservoir through the pump to the upstream particle counter (PC₁), through the test filter assembly, then through the downstream particle counter (PC₂) before returning to the reservoir. ISO medium test dust is injected upstream to maintain a target particle count at PC₁. Beta ratio β = PC₁ ÷ PC₂.RESERVOIRPUMPISO MTD INJECTIONPC1UPSTREAMCOUNTERcounts NᵤTEST FILTERΔP SENSORPC2DOWNSTREAMCOUNTERcounts Nd←── return to reservoir ───flow ctrlβ = Nᵤ / Ndβ₁₀(c) — ISO 16889 notationsubscript = particle size (µm)ISO 16889 · ISO 11171
Schematic of the multi-pass test loop: reservoir, pump, upstream particle counter PC₁, test filter housing with ΔP sensor, downstream particle counter PC₂, and return line. Contamination injection point upstream of PC₁. Beta ratio β = PC₁ ÷ PC₂.

GOVERNING STANDARDS

ISO 16889
ISO 11171

ELIMFILTERS TECHNOLOGIES

NANOFORCE™
SYNTRAX™

APPLICABLE SYSTEMS

Hydraulic Protection
Lubrication Protection

REVISION METADATA

Versionv1.0.0
Statuscurrent
Last Reviewed2026-07-08
Next Review2027-07-08

RELATED ENGINEERING ARTICLES

→Iso 16889 Multipass Test
→Beta Ratio
→Testing And Validation
→Fluid Cleanliness