Teledyne 9060 - Zirconium oxide flue gas oxygen analyzer - Manual (Page 77)

9060-Zirconia Analyser
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6.8 TEST EQUIPMENT REQUIRED
All measurements are simplified if a transmitter is connected to the probe or sensor.
Readings can then be easily taken of probe or sensor impedance, EMF, temperature and
percent oxygen. The transmitter also provides proper heater control for heated probes or
sensors.
The following tests are described using readily available workshop equipment where a
transmitter is not available. If a transmitter is available the same test procedures will
apply. First check all alarms on the transmitter, allowing time for the probe or sensor to
heat up after switch on.
An instrument to measure probe or sensor EMF and temperature is required. A 3 1/2 or 4
1/2 digit multimeter will perform both measurements.
A separate temperature indicator to suit the probe or sensor thermocouple type is also
useful, although not necessary.
A reference air pump is required and a cylinder of calibration check gas e.g. 2 % oxygen
in nitrogen. The cylinder should have a pressure and flow regulator. Both of these are
inexpensive devices available from gas supply companies. The calibration check gas
should be chromatograph tested to an accuracy of 0.1 % oxygen.
TEST EQUIPMENT FOR UNHEATED PROBES
A small test furnace capable of raising the probe tip temperature to over 700°C (1300°F) is
required. The furnace should have a uniform temperature for about 50 mm (2”) either side
of the sensor tip.
TEST EQUIPMENT FOR HEATED PROBES OR SENSORS
If a 9060 Analyser is available at the test location then no other equipment will be required.
If not, then a controllable power source for the heater is required. A Variac (variable
transformer), set to approximately 80 volts will regulate the probe or sensor temperature to
over 700°C (1300°F).
6.9 TESTING A PROBE OR SENSOR
With the probe or sensor heated to over 700°C (1300°F), either from a small test furnace
or its own internal heater, connect a digital multimeter to the probe or sensor electrode
conductors. Connect the multimeter positive to the internal electrode conductor. Connect
reference air to and apply a gentle purge of air to the probe calibration check port.
Reference airflow should be 50 to 500 cc/minute (6 to 60 scfm). The multimeter should
read zero millivolts + two millivolts. If not, then there is a problem with the probe
electrodes and the sensor needs refurbishing. Normally a faulty probe electrode is
indicated with a high source impedance. 1234 sensors do not require reference air but a
gentle flow of air should be admitted into the sample connection.
To test the source impedance, set the multimeter to read ohms and take a measurement,
within a couple of seconds, of the probe or sensor impendence. Reverse the multimeter
and repeat the reading. Take the average of the two readings for an approximate