Thermo Scientific FOCUS GC, Instruction Manual

Page: 148 / 356

Chapter 7
Column
Keeping Leaks Under Control
148 Instruction Manual
OPERATING SEQUENCE
Performing a Column Evaluation
The column flow control in the FOCUS GC is indirect. This means that the GC
regulates pressure to control the flow of gas through the column. To do this, the
GC relies on a column constant. The column constant is a measure of the columns
pneumatic resistance. Use the FOCUS GC’s column evaluation feature to
automatically calculate the column constant.
To perform the column evaluation, the system uses the correlation between the
applied pressure to the flow and the column temperatures. This operation must be
carried out every time a new column is installed. Before performing the column
evaluation, a manual checking for leaks of the system must be carried out.
The GC must not be performing a run and must be isothermally stable before you
can perform a column evaluation.
1. In Main Menu move the cursor until
Carrier
is selected, then press ENTER .
2. Scroll to
Column evaluation
and press
ENTER
to open
COLUMN
EVALUATION
menu.
3. To start column evaluation, scroll to
Run column eval
and press ENTER .
NOTE To exit Column evaluation menu without performing column evaluation, scroll to Exit w/o
column evaluation and press ENTER.
CARRIER (He)
Column evaluation
COLUMN EVALUATION
Run column eval.
K = 1.0
Exit w/o column eval