Thermo Scientific 42iQD, Инструкция по эксплуатации

Страница: 162 / 286

Calibration
Calibration
4-10 42iQD Instruction Manual Thermo Scientific
Use the following procedure to connect the GPT apparatus to the analyzer.
1. Assemble a dynamic calibration system such as the one shown in Figure
4–1 .
2. Ensure that all flow meters are calibrated under the conditions of use
against a reliable standard, such as a soap-bubble meter or wet-test
meter. All volumetric flow rates should be corrected to 25 °C and 760
mmHg.
3. Precautions should be taken to remove O
2
and other contaminants
from the NO pressure regulator and delivery system prior to the start of
calibration to avoid any conversion of NO to NO
2
. Failure to do so can
cause significant errors in calibration. This problem can be minimized
by:
a.
Carefully evacuating the regulator after the regulator has been
connected to the cylinder and before opening the cylinder valve.
b. Thoroughly flushing the regulator and delivery system with NO
after opening the cylinder valve.
c. Not removing the regulator from the cylinder between calibrations
unless absolutely necessary.
4. Connect the analyzer sample bulkhead input to the output of the GPT
system.
Use the following procedure to adjust the instrument gain. This includes:
●
Setting the NO
x
background to zero
●
Calibrating the NO
x
channel to the NO
x
calibration gas
The NO
x
background correction is determined during zero calibration.
The background signal is the combination of electrical offsets, PMT dark
current, and trace substances undergoing chemiluminescence. For more
detailed information, see “ Calibrate NOx Background ” in the “ Operation ”
chapter.
Use the following procedure to set the NO
x
background to zero.
Connect GPT Apparatus
to the Analyzer
Adjust Instrument Gain
Set NO
x
Background to Zero