GE MOA 280i, Руководство по эксплуатации и обслуживанию

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GE Analytical Instruments ©2006 DLM 14291 Rev. A
6-10
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Flow (mL/min)
Relative NOA Response
C
e
ll Pressure (torr)
FIGURE 7-2: Flow/Response/Cell Pressure Characteristics of NOA
Flow/Response Characteristics of NOA 280i
Figure 7-2 shows the relative response and reaction cell pressure of the NOA as a
function of gas flow (in mL/min at 760 torr and 25 °C) into the analyzer. The
optimum flow rate into the analyzer is ~175 to ~250 mL/min. Over this flow range,
the response of the NOA is independent of flow into the analyzer (<2% deviation
from maximum) and small changes in flow rate will not cause changes in the
response of the NOA. At higher flow rates, sensitivity of the NOA decreases due to
quenching at higher reaction cell pressures. At lower flow rates, sensitivity also
decreases as fewer NO molecules enter the reaction cell and react with ozone.
The standard flow restrictor provides a flow of ~200 mL/min into the analyzer.
For measurement of exhaled NO in small animals and some other applications,
operation at lower flow rates may be required. For these applications, flow