Varian 450-GC, User Manual

Page: 41 / 205

Installation
Page: 22 User Manual 450-GC Varian, Inc.
Set Carrier Gas Flow Rate to Condition Column
To condition the column, flow rates need only be approximate. For packed
columns and wide bore (0.53 mm ID) capillary columns set the flow rate to
10 - 20 mL/min. Press the FLOW / PRESSURE key, select the appropriate
Injector by location and set the initial flow to 10 - 20 mL/min (15 mL/min for a
wide bore column and 20 mL/min for a packed column).
Use the following guide to set an appropriate column flow for either the 1177 or
the 1079 PTV Injector with narrow bore capillary columns. With manual
pneumatics the pressure is set using either the 1177 or the 1079 PTV back
pressure regulator on the pneumatics panel. If the Capillary Injector has EFC
press the FLOW / PRESSURE key, select the appropriate Injector by
location and set the pressure according the table:
Table 9: Column condition head pressure
For capillary columns , the gasflow through t he column is verified by
dipping the detector end of column into a beaker cont aining a
solvent, such as isopropanol. Positive carrier gas flow should b e
indicated by a stream of bubbles.
Injector Conditioning
It may be necessary to bake out the Injector if it has become contaminated
during the re-assembly process, i.e. if the internal parts were placed on dirty
surfaces or touched with bare hands. Then, both the Injector and column
should be conditioned. See section Maintenance, Instructions for High-
Temperature bakeout of Injectors on page 433.
To prevent c ontamination and overheating of t he fused sili ca
column, the colum n must NOT be connected to t he Injector dur ing
the Injector bake-out procedure.
Column ID Head Press ure
250
μ
m 170 kPa (25 psi)
320
μ
m
100 kPa (15 psi)
530
μ
m
35 kPa (5 psi)