ISO 5352-1:2023

Overview - ISO 5352-1:2023 (Hydraulic fluid power test method)

ISO 5352-1:2023 defines a standardized test method to determine the characteristic discharge flow rate and thermal losses of gas‑loaded accumulators with separators used in hydraulic fluid power systems. The standard specifies test-bench configuration, measurement devices, procedures and reporting requirements to produce repeatable and comparable performance data for accumulators.

Key technical topics and requirements

• Test bench design and operating principle
  • Hydraulic schematic and required components (fluid power supply, pressure relief, valves, distribution block, gas filling system, flowmeter, reservoir).
  • Minimise dead volume and pressure losses; ensure a maximum pressure loss of 0.5 MPa at the design maximum instantaneous flowrate.
  • Valve actuation and timing: opening/closing times should be short relative to charging/discharging duration (max ≈ 8% ratio); industrial valves should not be faster than 50 ms.
• Measurement requirements
  • Gas and hydraulic sensors positioned close to the accumulator ports; gas pressure and temperature measured on an adapter at the gas interface.
  • Flow measurement options: graduated reservoir, weighing system, or flowmeter - ensure repeatability when determining mean flow rate.
  • Recommended measurement accuracy: ±0.5% for pressures and ±0.8 °C for temperatures.
• Thermal measurement specifics
  • Gas temperature sensor response time recommended ≤ 0.1 s to capture rapid compression/expansion effects.
  • Sensor placement: outside the boundary layer (typically ≥ 30 mm from internal wall) to avoid biased gas temperature readings.
• Data acquisition and analysis
  • High sampling frequency during dynamic phases; minimum of 100 data points during the dynamic phase is considered sufficient.
  • Discharge time should be measured accurately (recommendation ±1% accuracy) from pressure signals to compute mean discharge flow rate.
• Documentation
  • Test report must include ambient conditions, accumulator orientation/position, charging/discharging pressures, and measured data. Annexes A–F provide examples of data recording, analysis, test bench layouts (1–20 L), and sample test reports.

Practical applications and users

ISO 5352-1:2023 is intended for:

• Accumulator manufacturers validating performance claims (flow rates, thermal behavior).
• Testing laboratories performing type testing, R&D or quality control.
• OEMs and hydraulic system designers sizing accumulators and predicting system behavior.
• Certification and conformity assessment bodies needing standardized methods for verification.
• Maintenance teams requiring baseline performance data for troubleshooting or lifetime assessment.

By following ISO 5352-1:2023, stakeholders obtain repeatable, comparable measurements that support safe and efficient hydraulic system design and procurement.

Related standards

• ISO 5598 - Fluid power systems and components - Vocabulary (normative reference used for terms and definitions).
• Other parts of the ISO 5352 series (see ISO website for the complete list) provide complementary guidance on accumulator testing and characterization.