Volatiles Interface Theory Of Operation; Splitless Mode - Agilent Technologies 6890 Series Service Manual

250 Volatiles Interface
Theory of operation
Supply
Figure 250-1

Splitless mode

When you introduce a sample, the solenoid valve remains closed while the
sample enters the interface and is transferred to the column. At a specified
time after the sample is introduced, the solenoid valve opens.
Before Pre Run, when the GC is preparing for sample introduction, total flow
to the interface is measured by a flow sensor and controlled by a proportional
valve. Column flow is controlled via back-pressure regulation. See
Figure 250-1.
2 of 30
Split SPR
Vent Vent
Total flow
control loop
SPR
FS
PV1
PS
PV2
VI flow control diagram: split mode splitless mode (Idle or after
sampling end)
Inlets
Agilent 6890 Gas Chromatograph Service Manual
Trap
Valve
open
Sampler
To Column
Jun 2001