24 AZ10 OXYGEN ANALYZER | COMBUSTION GAS ANALYSIS | OI/AZ10-EN REV. A
8 Test gas and reference air connections
Test gas connection
CAUTION
Use clean dry instrument air free from hydrocarbons, or
traceable certified bottled test gas mixtures of O/N only.
Figure 21. A flowmeter
must be fitted to the test gas line to restrict/regulate the flow.
flowmeter.
Refer to topage 28 for pneumatic entry types.
Figure 21 AZ10 probe – test gas connection
Test gas inlet
sensor testing using a test gas.
If the sensor is connected permanently to the test gas supply
pipework:
•
solenoid valve, manually operated valve or non-return valve
pipework, as close to the test gas inlet valve as possible
• keep the valve closed when the calibration system is not
in use
CAUTION
If the test gas connection is not sealed when not in use, air
leaking into the sensor via the connection causes
measurement errors. In a pressurized process, gases
venting to atmosphere through the connection cause
corrosion of, and/or block, the test gas tube. In a negative
pressure process, air leakage causes high O reading errors.
NOTICE
•
gases as this is the sensor’s zero point. Alternative
representative gases can be used according to local
environmental conditions.
• To ensure better accuracy, use 2 test gases that represent
the top and bottom limits of the known operating range.
• Due to resolution accuracies, do not calibrate the system
.
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