NDIR Gas Analyzer
Operational Theory 2
Teledyne Analytical Instruments., - Rev. 3
15
the instrument with a flow rate between 0.2–2.0 liters per minute (2.0 to
5.0 liters per minute for low level optical bench)
at 5 psig or less
. For
samples greater than 5 psig contact factory. The sample temperature must
be in the range of -10 to 50°C (14–122)°F.
WARNING: The maximum rated pressure of the sample cell is 5 psig.
Exceeding this pressure at any time may cause the sample cell to
fail. This could result in harmful release of sample gas.
The following are items to be provided by the customer:
• Calibration
gases
• Nitrogen
(N
2
) for zero calibration
•
Span calibration gas
Use a span gas with a concentration of the gas of
interest greater than 50% of the largest desired
measurement. The span gas should be between 10%
and 100% of the instrument’s full scale, preferably
around 80%. For example, if the largest expected
reading is 3000 ppm, then the calibration gas should be
at least 1500 ppm.
The balance of the span gas should be N
2
.
If the instrument has a dual optical bench (Model
IR7000B or IR7000D), the span gas must contain
calibration values for both species being measured.
If an optional oxygen (O
2
) sensor is installed, the span
gas must contain a calibration value for O
2
. If the 0–
25% O
2
sensor is installed, use a calibration gas
containing 20% O
2
.
•
Pressure regulator, flow adjustment valves, tubing and fittings
for delivering properly conditioned sample gas to the
instrument.
The sample gas pressure must be less than 5
psig
. For pressures above 5 psig contact factory.
• Pressure regulator, flow adjustment valves, tubing and fittings
for delivering calibration (zero and span) gas to the instrument.
•
If the automatic calibration feature is to be used, the customer
must also supply 2 solenoid valves. The split architecture
versions of this instrument are capable of handling 3 solenoid
valves. Refer to Section 3
Installation and Setup
for details
regarding the installation of these components.
• The sample gas should be vented to atmospheric pressure. If the