Overview
ISO 2941:2009 - "Hydraulic fluid power - Filter elements - Verification of collapse/burst pressure rating" specifies a standardized test method to verify a hydraulic filter element’s ability to withstand a designated differential pressure in the intended flow direction. The procedure pumps a contaminated fluid through the element until either structural collapse/burst occurs or the target differential pressure is reached without failure. The standard is used to confirm the structural integrity and collapse/burst pressure rating of filter elements in hydraulic fluid power systems.
Key topics and requirements
- Test objective: Verify collapse/burst pressure rating of a filter element under realistic contamination loading.
- Test circuit and apparatus: Typical components include a test filter housing, pump and motor (maintain constant flow ±5%), reservoir designed to keep contaminants in suspension, connectors/valves, differential pressure transducer, flowmeter and an electronic strip chart recorder or data logger (recommended response 40–100 Hz; Annex A suggests >50 Hz).
- Fluid and contaminant: Use a fluid compatible with filter materials per ISO 2943; contaminants are inert particulates such as ISO 12103‑1 A2 (Fine) or A3 (Medium) test dust. Contaminant must not strengthen the element.
- Test procedure essentials:
- Pre-check fabrication integrity per ISO 2942 (first bubble point).
- Determine test flow rate (manufacturer’s nominal or 50–80% of nominal) and temperature (15–40 °C unless specified).
- Inject contaminant continuously or intermittently at ≤5% of estimated contaminant capacity per injection interval (preload of 50% capacity allowed by agreement).
- Record differential pressure versus contaminant mass added until collapse or target pressure is reached.
- Acceptance criteria:
- No visual failure after ISO 2942 integrity test, and
- No abrupt decrease in the slope of the differential pressure vs. contaminant mass curve prior to the rated collapse/burst pressure (see Annex C).
- Reporting: Required data include test flow rate, maximum differential pressure achieved, fluid type/viscosity/temperature, contaminant type, flow direction, and minimum collapse/burst rating (Annex B provides a report form).
Applications and users
- Filter manufacturers validating product structural ratings for catalogues and certifications.
- Test laboratories performing hydraulic filter qualification and performance verification.
- OEMs and component specifiers requiring verified collapse/burst ratings for hydraulic system safety and reliability.
- R&D and quality assurance teams assessing element design robustness under contamination loading.
Related standards
- ISO 2942 - Verification of fabrication integrity and first bubble point
- ISO 2943 - Material compatibility with fluids
- ISO 5598 - Fluid power vocabulary
- ISO 12103‑1 - Arizona test dust (filter evaluation)
- ISO 1219‑1 - Graphic symbols for fluid power diagrams
Keywords: ISO 2941, collapse/burst pressure, hydraulic fluid power, filter elements, differential pressure, contaminant injection, filter testing, verification.
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