12 Injection Port
12.3 Direct Injection System
148
GC-2014
When you set the linear velocity, the system calculates the column inlet pressure based
on the inner diameter, the length and the film thickness of the column. The linear velos-
ity is set separately so that the linear velocity desired occurs at the initial temperature in
the oven temperature program.
If you set the control mode to “VELOCITY”, the column inlet pressure automatically
changes so that the linear velocity remains constant during the oven temperature
program.
TOTAL FLOW RATE
Range: 0.0−1200.0 ml/min (Refer to Fig. 3.5.1), Default: 50.0 ml/min
Set the total flow rate, which is the sum of “column flow rate + split flow rate + septum
purge flow rate”.
CONTROL MODE
Selection: PRESS/VELOCITY/FLOW, Default: PRESS
PRESS: Controls the system so that the column inlet pressure remains constant during
an oven temperature program.
VELOCITY: Controls the system so that the linear velocity remains constant during an
oven temperature program.
FLOW: Controls the system so that the set flow rate remains constant.
CARRIER GAS TYPE
Selection: He/N2/H2/Ar, Default: He
Specify the carrier gas type supplied to the AFC.
This parameter is used for the measurement/control of the flow rate.
If this parameter is set incorrectly, flow rate calckulations may not be performed
incorrectly.
(Example: If this parameter is set to “N2” when He is actually used, the displayed total
flow rate, column flow rate and linear velocity are lower than the actual values.)
1 The column flow rate ranges is from 0 to the value at which the calculated column inlet pressure is
970 kPa or less and the calculated total flow rate is 1,200 ml/min or less.
2 The linear velocity ranges is from 0 to the value at which the calculated column inlet pressure is
970 kPa or less.
12.3.2.3 PF menu
PF menu Description
Reference
section
Column
Sets inner diameter, length and film thickness of capillary column.
Values set here are used in column inlet pressure caluculations from
column flow rate or linear velocity (or vice versa).
If these parameters are not set correctly, calculations are not performed
correctly.
12.2.3
On/Off
Set the flow controller to be used to “On.” When the GC starts, the AFC in
the current analytical line which is set to be “On” is controlled.
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Press Prog Sets the column inlet pressure program. 12.2.5
FLOW Prog Sets the total flow rate program. 12.2.6
Purge Sets the septum purge flow rate. 12.2.8
Offset
Performs offset calibration of the AFC sensor.
This calibration contributes to good reproducibility of results.
12.4
Next Flow
Toggles among the AFC setup screens if two or more AFCs are installed in
this system.
The [FLOW] key can also be used to Switch screens.
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NOTE
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