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Calibration
Equipment Required
Dynamic Parameter
Specifications for
Gas Titrator
Determining GPT System
Flow Conditions
4-6
Model 42i Trace Level Instruction Manual
Zero Air
A source of zero air free of contaminants should be used as described earlier
in this chapter. Contaminants can cause a detectable response on the
instrument and may also react with the NO, O
phase titration.
Use the following definitions for the remainder of this chapter.
P
=
R
[NO]
=
RC
t
=
R
[NO]
=
STD
F
=
NO
F
=
O
V
=
RC
F
=
T
The O
generator (ozonator) airflow rate and the NO flow rate must be
3
adjusted such that the following relationships hold:
Use the following procedure to determine the flow conditions to be used in
the GPT system.
1. Determine F
should be equal to the analyzer demand plus 10 to 50 percent excess.
2. Establish [NO]
required at the output manifold. [NO]
Dynamic parameter specification to ensure complete reaction of the
available O
, ppm-min
3
NO concentration in the reaction chamber, ppm
residence time of the reactant gases in the reaction chamber, min
Concentration of the undiluted NO standard, ppm
NO flow rate, sccm
O
generator air flow rate, sccm
3
Volume of the reaction chamber, cc
Analyzer demand plus 10 to 50% excess
≥
=
[NO
t x
2.75
]
P
R
R
RC
[NO
]
=
[NO
]
RC
STD
(
V
RC
=
t
R
+
F
F
O
NO
, the total flow required at the output manifold, which
T
as the highest NO concentration that will be
OUT
, or NO
during the gas
3
2
ppm
-
min
F
NO
+
)
F
F
O
NO
<
2
min
should be about equal to
OUT
Thermo Fisher Scientific
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Troubleshooting
