Portable Trace Oxygen Analyzer
Maintenance
Teledyne Analytical Instruments
29
4.7 Temperature Compensation
The micro-fuel cell has an inherent positive temperature coefficient.
Compensation is performed internally by the microprocessor and needs no
further adjustment.
Contact the factory if you suspect temperature related inaccuracies
during monitoring and are operating within the instrument’s temperature
operation range.
4.8 Leak Testing
WARNING:
IF A LEAK IS SUSPECTED IN THE UNIT, DO NOT
ATTEMPT TO TIGHTEN THE DISCONNECT
FITTINGS. THE FITTINGS ARE POTTED IN EPOXY
AND TIGHTENING THEM WILL BREAK THE SEAL.
To check for leaks, TAI recommends one of the following
procedures:
Procedure I:
1.
Purge the instrument to as low a value as possible. Use a
sensitive range for analysis for instance, 0-1% range Take
note of the oxygen concentration.
2.
Place the vent line in water and disconnect the sample.
3.
Next, disconnect the vent line and use the same analysis
range. The reading should not increase above the level to
which you purged to.
Procedure II:
1.
Purge the instrument with nitrogen at the sample port.
2.
Note the reading once it has stabilized and at a flowrate of
approximately 1 SCFH.
3.
Increase the flowrate from 1 SCFH to 2 SCFH.
4.
Note how much the reading has changed after a few minutes.
5.
Reduce the flowrate to 0.5 SCFH.
6.
Note how much the reading has changed.
7.
The reading should change by less than 10% of the original
value
