Teledyne 9110TH - Nitrogen Oxides Analyzer - Manual (Page 44)

Model 9110TH NOx Analyzer Getting Started
Teledyne Analytical Instruments 24
3.5. PNEUMATIC CONNECTIONS
Note To prevent dust from getting into the analyzer, it was shipped with small
plugs inserted into each of the pneumatic fittings on the rear panel.
Remove and store the dust plugs for future use, such as storage, moving,
shipping.
CAUTION!
Do not operate this instrument until you’ve removed dust plugs from SAMPLE and EXHAUST
ports on the rear panel!
Table 3-8: Inlet / Outlet Connector Descriptions
REAR PANEL LABEL FUNCTION
SAMPLE
Connects the sample gas to the analyzer. When operating the analyzer
without zero span option, this is also the inlet for any calibration gases.
EXHAUST Connects the exhaust of the analyzer with the external vacuum pump.
SPAN
On Units with a zero/span valve, this port connects the external calibration gas
to the analyzer.
ZERO AIR
On Units with a zero/span valve, this port connects the zero air gas or the zero
air cartridge to the analyzer.
3.5.1. ABOUT ZERO AIR AND CALIBRATION (SPAN) GASES
3.5.1.1. Zero Air
Zero air or zero calibration gas is defined as a gas that is similar in chemical
composition to the measured medium but without the gas to be measured by the
analyzer, in this case NO and NO
2
. If your analyzer is equipped with an external zero
air scrubber option, it is capable of creating zero air from ambient air.
If your application is not a measurement in ambient air, the zero calibration gas should
be matched to the matrix of the measured medium. Pure nitrogen could be used as a
zero gas for applications where NO
X
is measured in nitrogen. Special considerations
apply if measuring NO
X
in a matrix that does not contain oxygen, see Section 8.3.11 for
more information.
3.5.1.2. Calibration (Span) Gas
Calibration (or Span) 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 measurement range.
In this case, NO
X,
NO and NO
2
measurements made with the 9110TH/M, 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 between 0 ppm and 500 ppm, an
appropriate span gas concentration would be 400 ppm NO
x
.