SERVO
PRO NANOCHROME Gas
Analyser
109
04416001A / Revision 7
The dilution ratio is determined for each impurity, as follows:
1.
Turn off valve on span gas cylinder and allow to flow rate to stabilise for
approx. 5 minutes.
2.
Measure the flow F1 coming out of sample vent while analyser is controlling
the sample flow at the set point. Enter the value F1 in the calibration menu
(see section 4.7 and Figure 40).
3.
Turn on valve on span gas cylinder to the correct pressure (30 psig) and
allow flow rate to stabilise for approx. 5 minutes. Make sure that analyser
controls sample pressure to the set point.
4.
Measure the flow F2 coming out of sample vent. Enter the value F2 in the
calibration menu (see Figure 40). The analyser will calculate the Dilution
Factor (F2/(F2-F1)) and display it in the calibration menu.
5.
Repeat step 1 to 6 for all chassis.
CAUTION
A SERVOPRO NanoChrome may consist of multiple chassis. Each chassis has
its own internal dilution system which will require verification of the dilution
ratios for each relevant impurity.
To reduce the analyser purge time during start-up, it is recommended
to activate the dilution system valve for a few minutes to purge dead
volumes. This is important if the external carrier gas line is
contaminated.
The sample inlet can be changed from process to span using the calibration
menu. If the analyser has multiple chassis, the internal dilution system for each
chassis will change state at the same time. Refer to calibration section.
CAUTION
The internal dilution system dilutes the calibration gas using carrier gas. Carrier
gas is only consumed for dilution when the internal dilution system is in use
(valve activated). If sample inlet 2 is not connected to a calibration bottle, it is
important to install a cap on sample inlet 2. Otherwise, carrier gas will be
vented from sample inlet 2.