Industrial Filtration Glossary
Technical definitions for industrial hydraulic and lubrication filtration. Each term includes specifications, application ranges, and cross-references to related concepts used across 90+ filter manufacturers.
Beta Ratio
The ISO 16889 measure of filter efficiency — the ratio of upstream to downstream particles at a given micron size.
Micron Rating
The particle size a filter is designed to capture, measured in micrometers. Determines what contaminants the element removes.
Collapse Pressure
The maximum differential pressure a filter element can withstand before structural failure, measured in PSID.
Differential Pressure
The pressure drop across a filter element caused by fluid resistance. Increases as the filter loads with contaminant.
Filter Media Types
The materials used to construct the filtration barrier — including microglass, cellulose, synthetic, and wire mesh.
Dirt Holding Capacity
The total weight of contaminant a filter can capture before reaching its terminal pressure drop, measured in grams.
ISO Cleanliness Code
The ISO 4406 standard for reporting fluid contamination levels using three numbers representing particle counts at 4, 6, and 14 microns.
Filter Cross-Reference
An equivalent filter from a different manufacturer that matches the original in dimensions, media, and performance specifications.
Absolute vs Nominal Filtration
The distinction between filters rated by multi-pass testing (absolute) and those rated by average particle removal (nominal).
Seal Compatibility
How seal materials like Viton and Buna-N interact with hydraulic fluids, determining temperature limits and chemical resistance.
Last verified: February 2026