Teledyne 316RA / RB / RAD / RBD - Oxygen analyzers - Manual (Page 15)

TELEDYNE ANALYTICAL INSTRUMENTS
11
Trace Oxygen Analyzer Model 316RA/RB/RAD/RBD
7. Re-introduce sample gas into the analyzer.
NOTE: Calibration (particularly when the span gas is air) should be per-
formed as rapidly as possible, and the analyzer returned to the
sample gas as soon as calibration is complete. The longer the
instrument is exposed to the 209,000 ppm oxygen concentration of
air, the longer it will require to return to 10 ppm full scale sensitiv-
ity.
Alarm Setting (Optional)
The alarms are set using the adjustable front panel controls, and are
fully adjustable (0-100%) in each range. To set the optional alarm(s), use
the following example: If the range is 0-1,000 ppm and you want the alarm
to activate at 400 ppm, set the alarm dial to 40.0 (40% of 1000 ppm).
Routine Operation
Sample Flow. Adjust to a maximum of 4 SCFH (a nominal level of 2
SCFH is recommended).
Calibration. No prescribed routine calibration period is recom-
mended. TAI feels that the intervals between calibration should be dictated
by your application. If using the instrument to certify the oxygen content of
a product for delivery, then a calibration of the instrument before certifica-
tion is a good idea. If the instrument is used to monitor or guard a process
for predetermined limits of acceptability, use your knowledge of the
process and the evidence provided by the instrument to determine when a
calibration check is needed.
Shutdown. Whenever it becomes necessary to cut off the sample
flow, the following procedure minimizes the diffusion of air into the
instrument and helps to maintain the cell in a low ppm oxygen environ-
ment.
1. Close the throttle valve completely.
2. Immediately close the cell shutoff valve.
With the valves completely closed, the output indication will eventu-
ally come to equilibrium somewhere on the X100 scale as explained in the
first paragraph under Electrical Start-up.