Teledyne 306WA - Analog trace oxygen analyzer - Manual (Page 24)

4-8
4.0 Operations 4.0 Operations 4.0 Operations 4.0 Operations 4.0 Operations Model 306W Model 306W Model 306W Model 306W Model 306WA A A A A
TELEDYNE ELECTRONIC TECHNOLOGIES
Analytical Instruments
4.6 4.6 4.6 4.6 4.6 Power Power Power Power Power
When power is turned on, it is used to heat the cell compartment and
to provide current to the calibrator. The cell operates without applied
power, but its output will vary with changes in ambient temperature.
4.7 4.7 4.7 4.7 4.7 Warm-Up and Stabilization Warm-Up and Stabilization Warm-Up and Stabilization Warm-Up and Stabilization Warm-Up and Stabilization
When the analyzer is initially put into operation, the air in the lines and
sample passages will drive the output indication to the top of the scale. The
time required to sweep out this residual air may be several hours before an
on-scale indication is reached. During this time the cell compartment is
heating and reaching its controlled temperature.
4.7.1 4.7.1 4.7.1 4.7.1 4.7.1 Calibration Calibration Calibration Calibration Calibration
The analyzer is calibrated by adding a known amount of oxygen into
the sample stream. The sensitivity of the analyzer is adjusted until the
change indicated by the analyzer is equal to the amount of oxygen actually
added.
1. Adjust the sample flow rate until the flowmeter float is centered
in the flowmeter reference indicator. Note the reading of the
external recorder or meter.
2. Turn the calibrator power switch to ON. Adjust the calibrator
current dial to read the amount of oxygen to be added. The dial
reads 0 to 100 PPM O
2
(See Appendix A4 for the O
2
settings).
3. Leave the power and current controls in the positions selected
above. The calibrator current will continue to flow until the
calibrator power switch is turned OFF.
4. If the external recorder/meter does not indicate the proper
amount of oxygen (sample reading plus added oxygen), adjust
the sensitivity control until it does.
5. When the output reaches the proper equilibrium, turn the
calibrator power switch to OFF. The recorder/meter will move
downscale to indicate the oxygen content of the sample.
If the output indication requires adjustment of more than 10%,
the indicated oxygen content of the sample will differ noticeably
from the original indication. Repeat steps 2, 3, and 4, using the
new sample oxygen content value as a starting point.
The above procedure should achieve the correct sensitivity setting
though a series of sucessive approximations.