WPI APOLLO 4000, Instruction Manual

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APOLLO 4000
OXYGEN DETECTION
World Precision instruments d-2
Calibration
For accurate results the sensor probe should be calibrated as closely as is
possible to the temperature at which the measurement is to be made.
Polarization
the user must select the correct poise voltage potential for oxygen applied to the
electrode (
Fig. B10 ). After initially connecting the oxygen sensor to the Apollo 4000
in on position, the probe current will be high — approximately 0,000 pA. the
current will decrease and settle to a stable value after a period of time — usually
six to eight hours. the iso-oXY-2 should always remain connected to the APollo
4000. When the APollo 4000 is turned off it no longer applies a polarizing voltage
to the electrode Hence, it may then take several hours for the background current
of the electrode to become stable once the APollo 4000
is switched back on
again.
Zero (Oxygen) Point Calibration
After polarization of the iso-oXY-2 as described above, a calibration for zero
percent oxygen may be carried out in pure nitrogen gas or in water saturated with
nitrogen. With stirring, the complete saturation of water with nitrogen may take
more than ten minutes. calibration in pure nitrogen gas is much
faster and generally considered more reliable. A plastic calibration
bottle (
Fig. D1 ) is supplied with the utility kit. connect a plastic
tube () from the side tube to a pure nitrogen gas source at a low
pressure (less than 5 psi) and purge the bottle with nitrogen gas.
insert the iso-oXY-2 (2) into the bottle through the top vent hole on
the bottle cap (3). the current should be observed to drop rapidly
(a few seconds) to a stable value. if the current value is not zero it
must be zeroed using the software.
Scale Factor Calibration
After the instrument has been zeroed (at 0% oxygen) using the
software, it must be calibrated by measuring at least one more
known concentration of oxygen.
2
3
1
Fig. D1