Varian 450-GC, User Manual

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1177 Split/Splitless Capillary Injector - Injectors
Varian, Inc. User Manual 450-GC Page: 161
Setting 1177 Gas Flow Rates
The gas flow rates for the 1177 Split/Splitless Capillary Injector can be set using
manual pneumatics or Electronic Flow Control. Note that a positive flow through
the column must be set before heating the column.
Do not heat the col umn ov en above 50 C without carrier gas flowi ng
through the column. The column phase can be irreversibly damaged.
EFC Pneumatics
Type EFC21 or EFC25 used with the 1177 Injector allows the user to set a
constant column head pressure, build a pressure program, or set a constant
column flow. In addition, a split ratio can be set or time programmed. A
pressure program is typically used to maintain the column flow at a constant
value while temperature programming the column oven. When Constant Flow
Programming is enabled, the pressure program needed to maintain constant
flow is derived whenever the method is loaded.
The 1177 is a pressure-controlled Injector; thus the column flow decreases with
increasing column temperature if the pressure remains constant. EFC method
parameters and status are accessible via the FLOW/PRESSURE key on
the 450-GC keyboard.