Calibration Testing: Flow meters are calibrated using standard flow devices (such as standard meter methods, gravimetric methods, volumetric methods, etc.) to ensure that their measurement accuracy meets specified requirements. For example, when employing the gravimetric method, fluid is collected and weighed at a specific flow rate (e.g., 10–100 L/min) to calculate the deviation between the actual flow rate and the displayed flow rate.
Repeatability Testing: The same flow rate is measured multiple times under identical conditions to calculate the degree of dispersion among the measurement results. The repeatability error should be less than ±0.5% of the flow meter's nominal value.
Linearity Testing: The flow meter's output is tested at various flow points (e.g., 20%, 50%, and 80% of the full scale) to analyze its linearity. Typical linearity error should be maintained within ±1%.
Pressure Loss Testing: The pressure differential between the flow meter's inlet and outlet is measured to assess its impact on the overall system. For instance, the pressure loss for gas flow meters at their rated flow rate is typically required to be less than 10 kPa.
Environmental Adaptability Testing: This includes testing for temperature tolerance (–20°C to 60°C), humidity tolerance (10% to 90% RH), and vibration resistance to ensure that the flow meter can operate stably even under harsh environmental conditions.
Response Time Testing: The flow meter's dynamic response speed is tested by subjecting it to a step change in flow rate; for industrial-grade flow meters, the response time is typically required to be less than 100 ms.
Long-term Stability Testing: The device is operated continuously for a period exceeding 30 days to monitor for zero-point drift and span drift; the magnitude of such drift should remain within ±0.2% per month.
