Teledyne T200, Руководство по эксплуатации, Страница: 288 / 425

Principles of Operation Teledyne API
– T200 NO/NO2/NOx Analyzer Operation Manual
286
0
20
40
60
80
100
120
140
0.5 0.9 1.1 1.3 1.5 1.7 1.9
Wavelength (micrometers)
In
ten
si
ty
(arbitra
ry u
n
its)
Optical Hi-Pass Filter Performance
NO + O
3
Emission Spectrum
Area of Sensitivity
Infrared


Visible
Spectrum
PMT
Response
0.7
Figure 13-2: T200 Sensitivity Spectrum
13.1.3. NO
X
AND NO
2
DETERMINATION
The only gas that is actually measured by the T200 is NO. NO
2
, and therefore NO
x
(which is defined here as the sum of NO and NO
2
in the sample gas), contained in the
gas is not detected because NO
2
does not react with O
3
to create chemiluminescence.
In order to measure the concentration of NO
2
, and therefore the concentration of NO
x
,
the T200 periodically switches the sample gas stream so that the pump pulls it through a
special converter cartridge filled with molybdenum (Mo, “moly”) chips that are heated
to a temperature of 315°C.
NO/NO
X
VALVE
AUTOZERO
VALVE
NO
2
+ Mo NO + Mo
y
O
z
at 315
˚C
3
1
2
1
3
2
NO
2
+ NO
from Sample Gas Inlet
O
3
from
O
3
Generator
NO only
MOLYBDENUM
CONVERTER
NO+O
3
PMT
To Exhaust
Manifold & Pump
To Exhaust
Manifold
& Pump
NO o
nly
Figure 13-3: NO
2

NO Conversion
06858E DCN7057