Top Page > Product Information > Principle of Mass Flow Instruments > 4. Calibration with actual gas and conversion factor method
Principle of Mass Flow Instruments
- 4. Calibration with actual gas and conversion factor method
- KOFLOC mass flow instruments are calibrated with N2 gas in
principle before shipment. The accuracy of thermal sensors cannot be guaranteed unless they are calibrated with actual gas.
The actual gases used for calibration at our company are N2, O2, H2, He, CO2, and Ar. Concerning other gases, certain conversion factors (CF) are used for correction after calibration with N2 gas.
For example, when Ar is fl owed through a mass fl ow instrument that was calibrated with N2 gas, a 1.4 times larger quantity of Ar than the reading of the mass fl ow instrument will fl ow, because the CF of Ar is 1.4. In other words, the fl ow of Ar = 1.4 x Reading of N2mass
fl ow instrument. The CF is calculated for various gases based on calculation and the accumulation of data obtained through measurement with actual gases.
However, the CF of one gas may not be exactly the same depending on the condition of the actual gas (temperature and pressure), the type of sensor of the mass flow instrument, and combination of the bypass (laminar fl ow element). The public standard CF should be used just as a standard value.
If you desire calibration with actual gas without using a CF, please provide us with the actual gas, and we will use it for calibration (this will incur a separate fee for gas calibration).
However, we cannot accept some dangerous gases in view of the safety of products and facilities. Please contact us in advance for details.
NEXT
TOP
About this commodity
