Teledyne 9110T - Nitrogen Oxides Analyzer User Manual
Page 57
Model 9110TH NOx Analyzer
Getting Started
Teledyne Analytical Instruments
57
Pure nitrogen (N2) could be used as a zero gas for applications where NOX is measured in nitrogen.
If your analyzer is equipped with an external zero air scrubber option, it is capable of creating zero
air from ambient air.
For analyzers without the external zero air scrubber, a zero air generator such as the Teledyne
Model 701 can be used. Please visit the company website for more information.
CALIBRATION (SPAN) GAS
Calibration gas is a gas specifically mixed to match the chemical composition of the type of gas being
measured at near full scale of the desired reporting range. To measure NO
X
with the 9110T NO
X
analyzer, it is recommended that you use a span gas with an NO
concentration equal to 80% of the
measurement range for your application
EXAMPLE:
If the application is to measure NOX in ambient air between 0 ppm and 500 ppb, an appropriate
span gas would be 400 ppb.
If the application is to measure NOX in ambient air between 0 ppm and 1000 ppb, an appropriate
span gas would be 800 ppb.
Even though NO gas in nitrogen could be used as a span gas, the matrix of the balance gas is different
and may cause interference problems or yield incorrect calibrations.
The same applies to gases that contain high concentrations of other compounds (for example, CO2
or H2O).
The span gas should match all concentrations of all gases of the measured medium as closely as
possible.
Cylinders of the following types of calibrated NO
x
and NO gas traceable to NIST standards specifications
(also referred to as EPA protocol calibration gases or Standard Reference Materials) are commercially
available.
Table 3-8: NIST-SRM's Available for Traceability of NO
x
Calibration Gases
NIST-SRM
4
TYPE
NOMINAL
CONCENTRATION
2627a
2628a
2629a
Nitric Oxide (NO) in N
2
Nitric Oxide (NO) in N
2
Nitric Oxide (NO) in N
2
5 ppm
10 ppm
20 ppm
1683b
1684b
1685b
1686b
1687b
Nitric Oxide (NO) in N
2
Nitric Oxide (NO) in N
2
Nitric Oxide (NO) in N
2
Nitric Oxide (NO) in N
2
Nitric Oxide (NO) in N
2
50 ppm
100 ppm
250 ppm
5000 ppm
1000 ppm
2630
2631a
2635
2636a
Nitric Oxide (NO) in N
2
Nitric Oxide (NO) in N
2
Nitric Oxide (NO) in N
2
Nitric Oxide (NO) in N
2
1500 ppm
3000 ppm
800 ppm
2000 ppm
2631a
1684b
Oxides of Nitrogen (NO
x
) in N
2
Oxides of Nitrogen (NO
x
) in N
2
2500 ppm
100 ppm
Note
The NO2 permeation tube included with the 9110T’s optional Internal