Calibrating a thermal mass flow meter requires using the factor to correct the output for each gas. By default, thermal mass flow meters are calibrated for nitrogen/air. Thus, the flow meter range listed is valid only for nitrogen/air. Higher end models will have the option to choose the gas and the output will be corrected accordingly.
How to calibrate your mass flow meter
Calibration is typically done using the actual fluid. By comparing the flow rate to the recommended range listed, you can calibrate the mass flow meter until the actual flow rate matches the recommended range.
Here are the steps you need to follow when installing a mass flow meter
- Make sure the piping system is clean before installation
- Install a filter upstream to ensure a moisture and oil-free gas stream and a downstream filter if back flow is a concern
- Make sure the piping diameter is adequate for the flow rate and that there are no abrupt angles or objects in the flow path which can cause turbulence. Recommended pipe diameter is 10 times the distance between an angle and the inlet of the flow instrument
- Mount your mass flow meter in a horizontal position and avoid installing near heat sources or mechanical vibrations
- Check your system for leaks before applying fluid pressure