14
６−２．
Calibration
Perform gas calibration at new installation, 6 months inspection and sensor replacement.
６−２−１．
Required kit and tools for calibration
Prepare following jigs and tools to perform zero and span adjustments.
・Calibration adapter
・Calibration gas (standard gas for zero and span)
・Gas sampling bag for calibration gas
・Suction pump to lead calibration gas
・Flowmeter 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
Connect calibration adopter, 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.
③
Connect gas sampling bag for calibration to the IN side of the pump.
④
After reading by indicator/alarm unit gets stable, adjust the reading to zero with
respective potentiometer of indicator/alarm unit.
⑤
Stop the supply of zero gas, disconnect calibration adapter and confirm that the
oxygen reading returns to 20.9vol %.
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% O2 providing that the ambient pressure is 1 atm (1000±50hpa)
and contamination in air is negligible against span gas concentration.
②
Connect calibration adopter, 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.
③
Connect gas sampling bag for calibration to the IN side of the pump.
④
After reading by indicator/alarm unit gets stable, adjust the reading to the span gas
concentration with respective potentiometer of indicator/alarm unit.
⑤
Stop the supply of span gas, disconnect calibration adapter and confirm that the
oxygen reading is 20.9vol % (completion of span calibration).
