14
６−２．Calibration
Perform gas calibration at new installation, 6 months maintenance and sensor replacement.
６−２−１．Required kit and tools for calibration
Prepare following jigs and tools to perform zero and span adjustments.
•
Calibration gas (standard gas for zero and span)
•
Gas sampling bag for calibration gas.
•
Gas sampling bag for exhaust gas.
•
Suction pump to lead calibration gas
•
Flow meter with flow control valve (enable to control 1.0L/min).
６−２−２．Performing a zero adjustment
①
Pack the zero gas (Nitrogen more than 99.9 vol %) into gas sampling bag.
②
Disconnect piping for both gas inlet and gas outlet of this unit.
③
Connect flow meter （with flow control valve） and suction pump to the detector head.
Turn on the pump and adjust the reading of flow meter to 1.0±0.3L/min.
④
Connect gas sampling bag for calibration to the IN side of the pump and gas sampling bag
for exhaust gas to the outlet of this unit respectively.
⑤
After reading by indicator/alarm unit gets stable, adjust the reading to zero with
respective potentiometer of indicator/alarm unit.
⑥
Stop the supply of zero gas, disconnect gas sampling bag for calibration and confirm that
the oxygen reading returns to 20.9vol %.
⑦
Return disconnected piping to where they were (completion of zero adjustment).
６−２−３．Performing a span adjustment
①
Pack the span gas (fresh air for oxygen deficiency alarm instrument and their
concentration is around preset alarm level for other purpose) into gas sampling bag.
For simple calibration, you may be possible to use an ambient air as span gas
containing 20.9vol% O
2
providing that the ambient pressure is 1 atm (1000±50hPa)
and contamination in air is negligible against span gas concentration.
②
Disconnect piping for both gas inlet and gas outlet of this unit.
③
Connect flowmeter （with flow control valve） and suction pump to the detector head.
Turn on the pump and adjust the reading of flowmeter to 1.0±0.3L/min.
④
Connect gas sampling bag for calibration to the IN side of the pump and gas sampling bag
for exhaust gas to the outlet of this unit respectively.
⑤
After reading by indicator/alarm unit gets stable, adjust the reading to the span gas
concentration with respective potentiometer of indicator/alarm unit.
⑥
Stop the supply of span gas, disconnect gas sampling bag for calibration and confirm that
the oxygen reading is 20.9vol %.
⑦
Return disconnected piping to where they were (Completion of span adjustment).
