Laminar flow meter and element calibration

Laminar flow meter calibration is the process of establishing the accurate relationship between differential pressure across a laminar flow element and the actual volumetric flow rate for a specific gas, temperature and pressure. A traceable reference flow standard is used to determine correction factors or confirm the instrument’s accuracy across the required measurement range. UKAS accreditation ensures the reference standards and methods are independently assessed to ISO/IEC 17025:2017.

A laminar flow element measures flow indirectly by sensing the differential pressure created by laminar flow through parallel passages. It has no moving parts, offers high accuracy, and is less sensitive to upstream disturbances than many other flow technologies. A rotameter is a direct visual flow indicator using a float in a tapered tube. LFEs are generally preferred where accuracy and repeatability are priorities; rotameters where a simple visual check is sufficient.

For most regulated applications, annual calibration is standard practice. LFEs used as secondary flow standards in calibration laboratories may be calibrated more frequently, particularly before and after use in critical calibration work. The calibration interval should be defined by your quality management system and reflect the risk of drift and the consequences of inaccuracy in your specific application.

Yes. Labcal can calibrate laminar flow elements using air, argon, carbon dioxide, helium, oxygen and nitrogen. The calibration is specific to the gas used, so if your instrument is calibrated on air but used with nitrogen, a conversion factor must be applied. We can advise on multi-gas calibration requirements if your application involves more than one gas.

Measurement uncertainty depends on the flow range, gas type and specific instrument. Labcal’s UKAS accreditation requires us to calculate and report measurement uncertainty for every calibration, in accordance with ISO/IEC 17025:2017. The uncertainty is stated on each calibration certificate and can be compared against your instrument’s specified accuracy to confirm compliance.