Varian 450-GC, User Manual

Page: 39 / 205

Installation
Page: 20 User Manual 450-GC Varian, Inc.
Split Vent Flow and Septum Purge Flow
Whether you are making an injection in the split or splitless mode, a split vent
flow rate needs to be set. In this example the column flow is set to 1 mL/min,
the split vent flow is set to 100 mL/min corresponding to a split ratio of 100. A
split ratio of 100 means that for every mL of gas through the column, 100 mL/s
will flow out the vent. The split state is set in the Injector section of the 450-GC
method in case an EFC is installed or in the VALVE TABLE section of SAMPLE
DELIVERY in case an manual pneumatics is installed. In addition to a split state
a septum purge flow rate should also be set. The following information is for
setting a split vent flow rate with EFC installed. For either a 1177 or 1079 PTV
with manual pneumatics see the Injector section of the Operator’s Manual on
page 97 for further information.
1. Press the FLOW / PRESSURE key and set the appropriate head
pressure for your analytical column.
2. Press the INJECTOR key and select either the 1177 or the 1079 PTV
Injector by location.
3. When EFC is installed, in addition to programming the split state, the split
ratio can also be programmed.
4. Set the initial split state to ON and set the split ratio to 100.
5. Press the COLUMN OVEN
key. Turn the column oven off by pushing
on the button “Turn Oven Power Off”.
6. Allow the oven to cool down. Open the column
oven door and adjust the septum purge needle
valve located above the column oven until the
flow rate is in the range 3 - 5 mL/min. For EFC
equipped systems this value has to be entered
in the septum purge calibration routine.
Septum purge calibration
•
Select the SETUP key and select CALIBRATION.