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Teledyne API T500U CAPS NO
2
Analyzer with NumaView™ Software
083730510A DCN8172
Note
Zero air and span gases must be supplied at twice the
instrument’s specified gas flow rate. Therefore, the T500U zero
and span gases should be supplied to their respective inlets in
excess of 1800 cc/min (~900 cc/min x 2).
Z
ERO
A
IR
Zero air or zero calibration gas is similar in chemical composition to the measured medium
but without the gas to be measured by the analyzer. A zero generator, such as the Teledyne
API Model 701, can be used.
C
ALIBRATION
(S
PAN
)
G
AS
Calibration gas is specifically mixed to match the chemical composition of the type of gas
being measured at near full scale of the desired reporting range.
Alternatively, if a calibrator is available that is a trusted source of stable ozone, e.g.,
Teledyne API Model T700U with certified photometer, it is possible to use that O
3
output
directly to obtain the NO
2
concentration.
S
PAN
G
AS FOR
M
ULTIPOINT
C
ALIBRATION
Some applications, such as EPA monitoring, require a multipoint calibration where span
gases of different concentrations are needed. We recommend using an NO
2
gas of higher
concentration combined with a gas dilution calibrator such as the Teledyne API Model
T700. Calibrators mix high concentration gas with zero air to accurately produce span gas
of the desired concentration. Linearity profiles can be automated with these models and
run unattended overnight.
If a dynamic dilution system is used to dilute high concentration gas standards to low,
ambient concentrations, ensure that the NO
2
concentration of the reference gas matches the
dilution range of the calibrator. (Section 2.5.5 contains information about the dilution
option).
Choose the NO
2
gas concentration so that the dynamic dilution system operates in its mid-
range and not at the extremes of its dilution capabilities.
EXAMPLE:
•
A dilution calibrator with 10-10000 dilution ratio will not be able to accurately dilute a
5000 ppm NO
2
gas to a final concentration of 500 ppb, as this would operate at the
very extreme dilution setting.
•
A 100 ppm NO
2
gas in nitrogen is much more suitable to calibrate the analyzer
(dilution ratio of 200, in the mid-range of the system’s capabilities).
CAUTION!
If the presence of ozone is detected at any time, power down
the instrument and contact Teledyne API Technical Support
Summary of Contents for T500U
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