Varian 450-GC, User Manual

Page: 126 / 205

Injectors – 1079 PTV Injector
Page: 188 User Manual 450-GC Varian, Inc.
Septum Purge Calibration
The 450-GC is equipped with a septum purge
for the Model 1079 PTV Injector and is
controlled by a manual needle valve. This is
located behind the front cover of the GC.
The manual needle valve can offer
advantages over fixed restriction types as it
can be adjusted to suit the more demanding
applications. For the accurate display of total
column flow and velocity it does require
calibration when columns of different length
and diameter are installed.
With type EFC21, the septum purge calibration routine should be carried out
when the instrument is first set up or a new column is installed or when a
significantly different pressure point is chosen. Press the SETUP key and
click on Calibration.
The Calibration page will appear, choose Calibrate for the correct Injector (front,
middle or rear).
Enter the desired Column Head pressure. After a few seconds measure the
septum purge flow rate and adjust the septum purge valve (located behind the
column oven door) to the desired flow, enter this value (typical 3-5 mL/min) in
the Adjusted Septum Purge Flow Rate field.
Press OK.
Typical 3-5 mL/min