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perform that kind of function. Users should better have that plug valve by themselves. Especially when users
operate with caustic gas, general speaking, it should separately add one cut-off valve of MFC inlet and outlet to
protect operating security. After a long period operating, if the leakage rate of MFC valve outlet is not beyond 2%
F.S., it is the standard situation. Otherwise, it should be under maintaining.
6.4 Valves operating
When valve is operating PURGE, which should not be directly turned to AUTO, operation should be turned the
switch to OFF position and then turn it into AUTO to operating.
6.5 Installation Position
Keeping installation surface horizontal while installation. Please provide the installation position when ordering the
MFC. We will calibrate products according to the requirement of customers. The MFC might show the zero drift if
it is not installed as the same position of calibration. Customer can adjust zero to fix it.
6.6 Operation Pressure Resistance
Please be caution for the medium operating pressure of MFC, it should not be beyond the rage of specification of
inlet and outlet. Especially while operating under the high-pressure situation, the big differential pressure will affect
flow fail to shut off or lower adjustment. In case of using heavy flow rate of MFC, please be sure appropriately
widen tube and reduce gas internal resistance, if operating differential pressure is lower than the value of request, it
might could not be reach to the full scale flow rate value.
6.7 Calibration and Conversion
D07 series is calibrated by nitrogen. Other gas calibrations please inform in your order statements. When the
nitrogen calibration users use other gas operating, it could convert and calculate used gas flow rate by conversion
factors of appendix 8.1. Which means users could multiply the readout flow rate from MFC Readout Box with the
used gas corresponding conversion factors, the result will be the used gas corresponding mass flow rate of standard
situation.
For example, there is 1000 SLM (N2) calibrated MFC, the flow rate is displayed 860 SLM while firedamp
flowing, the conversion factors of firedamp is 0.719 from reference of appendix 9.1, the real firedamp
flow rate is 860 * 0.719= 618 SLM.
If users use the mixture gas, it could be calculated the conversion factors by the method which introducing in
appendix 9.2.
