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4.5 Interruption of the carrier gas supply
With an interruption of the carrier gas supply, e.g. during a change of the carrier
gas cylinder without use of the switchover unit, the analysis must be interrupted by
selecting the mode "STOP" on the analytical computer. If the analytical computer
has "STOP" status, – in other words, the running analysis was ended – all inlet
valves on the gas distribution (Figure 6: Gas chromatograph PGC 9300 / A - M)
are closed. If the carrier gas pressure at the measuring element has dropped
enough, the software automatically lowers the column temperatures to 30°C and
switches off the detectors. This is recognizable by the setpoint temperatures on
the Status screen on the controller. Once the setpoint temperatures have changes,
the measuring element can be switched off. If the supply with carrier gas has been
re-connected (regular flushing of pressure regulators and supply lines!), the inlet
pressure should be checked (inlet pressure regulating unit).
After the inlet valve (Figure 6: Gas chromatograph PGC 9300 / A and D) has been
opened, a further check can take place on the analytical computer ("Status"
screen). The device must remain in this state for at least 15 min.
Now the power supply for the measuring element can be switched on again. After
a wait time of an additional 15 min, the remaining inlet valves (Figure 6: Gas
chromatograph PGC 9300 / B, C and M) can be opened again. The analytical
computer must now be switched to the mode "Normal calib.". After successful cali-
bration, the analytical computer automatically switches over to "Autorun" mode.
Note
If the power supply was disconnected for more than 0.5 h, an additional
calibration should take place after about 1-2 h.
If error messages appear on the initial calibration or at the beginning of
the analysis, it may be due to the remains of foreign gases.
These messages should be acknowledged within 2 h after operation.
If the measuring element should be decommissioned for an extended period, the
device should be shut down. For this purpose, the measuring element must first be
disconnected from the power supply as described above. If possible, the supply of
the measuring element with carrier gas should continue for the duration of the
downtime by opening the inlet valve for helium (A) and if applicable argon (D) after
the measuring element has been shut down. If this is not possible, the exhaust gas
line should be provided with a gas-tight seal with a dummy plug after shutting
down the measuring element and interrupting the carrier gas supply until the time
of re-commissioning.
4 Connection and commissioning
Manual PGC 9300 EN07 June, 18th 2018
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