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Principles of Operation
10.1.1. GAS PHASE TITRATION MIXTURES FOR O
264
This dilution process is dynamic.
temperature and pressure of the various gases, but also receives data on actual flow rates
of the various MFCs in real time so the flow rate control can be constantly adjusted to
maintain a stable output concentration.
The T700 calibrator‟s level of control is so precise that bottles of mixed gases can be
used as source gas. Once the exact concentrations of all of the gases in the bottle are
programmed into the T700, it will create an exact output concentration of any of the
gases in the bottle.
Because ozone is a very reactive and therefore under normal ambient conditions a short-
lived gas, it cannot be reliably bottled, however, an optional O
included in the T700 calibrator that allows the instrument to be use to create calibration
mixtures that include O
3
This ability to generate O
to be used to create calibration mixture containing NO
process (GPT) by precisely mixing bottled NO of a known concentration with O
known n concentration and diluent gas (zero air).
The principle of GPT is based on the rapid gas phase reaction between NO and O
produces quantities of NO
NO
O
3
Under controlled circumstances, the NO-O
therefore the concentration of NO
accurately predicted and controlled as long as the following conditions are met:
The amount of O
used in the mixture is known.
3
The amount of NO used in the mixture is AT LEAST 10% greater than the amount
O
in the mixture.
3
The volume of the mixing chamber is known.
The NO and O
flow rates (from which the time the two gases are in the mixing
3
chamber) are low enough to give a residence time of the reactants in the mixing
chamber of >2.75 ppm min.
Given the above conditions, the amount of NO
to (at a 1:1 ratio) the amount of O
Since:
The O
flow rate of the T700‟s O
3
LPM);
The GPT chamber‟s volume is known,
The source concentration of NO is a fixed value,
Once the TOTALFLOW is determined and entered into the T700‟s memory and target
concentration for the O
3
Teledyne API – Model T700 Dynamic Dilution Calibrator
The T700‟s CPU not only keeps track of the
.
internally also allows the T700 Dynamic Dilution Calibrator
3
as according to the following equation:
2
NO
O
2
2
reaction is very efficient (<1% residual O
3
resulting from the mixing of NO and O
2
2
added.
3
generator is a fixed value (typically about 0.105
3
generator are entered into the calibrator‟s software, the T700
AND NO
3
2
generator can be
3
using a gas phase titration
2
h
(
light
)
being output by the T700 will be equal
06873E DCN7106
of a
3
that
3
Equation 10-3
),
3
can be
3
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