Teledyne 9110T - Nitrogen Oxides Analyzer - Manual (Page 249)

Model 9110T NOx Analyzer Instrument Maintenance
Teledyne Analytical Instruments 249
11.3.6. CHANGING THE INTERNAL SPAN GAS GENERATOR PERMEATION
TUBE
1. Turn off the analyzer, unplug the power cord and remove the cover.
2. Locate the permeation tube (see Figure 3-5) oven in the rear left of the analyzer.
3. Remove the top layer of insulation if necessary.
4. Unscrew the black aluminum cover of the oven (3 screws) using a medium Phillips-
head screw driver.
 Leave the fittings and tubing connected to the cover.
5. Remove the old permeation tube and replace it with the new tube.
 Ensure that the tube is placed into the larger of two holes and that the open
permeation end of the tube (plastic) is facing up.
6. Re-attach the cover with three screws.
 Ensure that the three screws are tightened evenly.
7. Replace the analyzer cover, plug the power cord back in and turn on the analyzer.
8. Carry out a span check to see if the new permeation device works properly (see
Section 9.3.4).
9. The permeation rate may need several days to stabilize.
ATTENTION COULD DAMAGE INSTRUMENT AND VOID WARRANTY
Do not leave instrument turned off for more than 8 hours without
removing the permeation tube. Do not ship the instrument without
removing the permeation tube. The tube continues to emit NO2, even at
room temperature and will contaminate the entire instrument.
11.3.7. CHANGING THE EXTERNAL ZERO AIR SCRUBBER (OPT 86C)
The external zero air scrubber that is included with several of the 9110T’s optional calibration valve
packages contains two chemicals:
 Pink Purafil © (P/N CH 9)that converts NO in the ambient air to NO
2
, and;
 Black, charcoal (P/N CH 1) that absorbs the NO
2
thereby creating zero air.
These chemicals need to be replaced periodically (see Table 11-1) or as needed.