Purged/Packed Inlet Theory Of Operation - Agilent Technologies 6890 Series Service Manual

220 Purged/Packed Inlet
Theory of operation
Flow
limiting
frit
Figure 220-1
The flow controlled mode shown above is used when no column dimensions
are configured in the 6890 GC.
Flow
limiting
frit
Figure 220-2
The pressure controlled mode shown above is used when capillary column
dimensions are configured in the 6890 GC.
2 of 20
Proportional
valve
Flow
Pressure
(PV1)
sensor
sensor
PS
FS
Total flow
control loop
EPC control packed column inlet (flow control mode — recommended
for packed columns)
Proportional
valve Flow
Pressure
(PV1) sensor
sensor
PS
FS
Inlet pressure
control loop
EPC control packed column inlet (pressure control mode —
recommended for capillary columns)
Inlets
Agilent 6890 Gas Chromatograph Service Manual
Septum purge
Septum holder
regulator (not
adjustable)
SPR
To Column
and Detector
Septum purge
Septum holder
regulator (not
adjustable)
SPR
To Column
and Detector
Purge Vent Flow
1.0 mL/min
Purge Vent Flow
1.0 mL/min
Jun 2001