Variable area flow meter calibration for liquids (rotameters)

Variable area flow meter calibration compares the meter’s indicated flow against a traceable liquid flow reference standard at defined points across the scale. The calibration certificate records the indicated flow, the reference flow, the deviation and the measurement uncertainty at each point. UKAS accreditation means the laboratory has been independently assessed to ISO/IEC 17025:2017.

Rotameter accuracy depends on the condition of the float and tube. Contamination, surface deposits and component wear change the float’s behaviour over time, shifting the indicated reading. Regular calibration identifies this drift and maintains confidence in the measurement, particularly where readings support ISO audits or quality assurance processes.

No. This page covers variable area flow meters used on liquids, calibrated on our UKAS-accredited water flow facility covering 0.5 mL/min to 500 L/min. Rotameters used on gas or air are calibrated under our gas and air flow scope. The same meter cannot simply be switched between gas and liquid service without recalibration, because the float behaviour depends on the fluid.

Calibration intervals should be defined by your quality management system based on the criticality of the measurement and the operating environment. Annual calibration is common in regulated industries, and meters in dirty or aggressive service may need more frequent checks because contamination directly affects accuracy.