Teledyne 9110AH - Nitrogen oxides analyzer - Manual (Page 42)

TELEDYNE Model 9110AH NO
X
Analyzer Operator Manual, 01620, Rev. F
4-10
4.2.8 Ozone Generator
Because of the instability of ozone, it is necessary to generate this gas inside the analyzer. The
ozone generation module consists of a switching power supply that drives a high voltage
transformer and silent discharge tube. The generator’s dry air supply uses a membrane drier to
supply air with a dew point of O
o
C or less. The exhaust side of the membrane is connected to
the vacuum manifold at the rear of the instrument. A complete description and service
requirements for this module can be found in Section 9.3.6.
Normal room air contains enough water vapor to damage the generator and components
downstream, therefore the ozone GENERATOR MAY NOT TURN ON IMMEDIATELY
AFTER POWER UP. The delay is built into the instrument to allow the dryer to start operating
and purge the system with dry air. Table 4-3 details the conditions for turning on the ozone
generator.
Table 4-3: Ozone Generator Start-up Timing
Time Since Last Power-up Ozone Gen State Program Action
< 1 hour ON at power-up Gen ON immediately after power-up.
> 1 hour OFF at power-up Wait 30 min, then turn gen ON.
4.2.9 NO
2
- NO Converter
The converter is a length of 1/8” tubing heated to 700 C. The converter's function is to reduce
nitrogen dioxide (NO
2
) to nitric oxide (NO). The temperature control for this module is done
by the computer. To accurately measure converter efficiency, there should be oxygen present in
the NO
2
calibration gas.
NOTE
For the converter to operate properly there should be a few
percent oxygen present in the sample stream.