User`s guide

Theory of Thermal Desorption
306
If SV4 is open, it will remain open for the three minutes and switch
with SV2. SV2 and SV4 (if selected) will switch three minutes after
the last tube heat.
If there are further desorptions, SV1 and SV2 switch to prevent the
carrier gas from entering the trap, but SV4 remains open, if outlet
split is enabled in the method. If Cycle Time is set to zero, when the
cold trap has reached its low temperature and a ready signal has been
received from the GC, the next sample tube is loaded.
Figure 89 Secondary (Trap) Desorption (with Outlet Split
Selected)
Overlapping Tube Desorption
To maximize productivity, tubes can be desorbed while
chromatography of the previous sample is in progress, provided the
successive tubes are analyzed using the same method. If the GC
cycle time is set to any value other than zero, the ATD/TD will start
Desorb
Flow Vent
Transfer Line
To GC
Sample
Tube
SV2
Carrier
Supply
SV1
Desorb Supply
Carrier
Pressure
Trap
Pressure
Regulator
2
3
4
1
Valve A
Position B
Leak
Pressure
Suppl
y
SV4
Outlet Split
SV5
Inlet Split
SV3
Desorb Vent
Inlet Split/
Tube Condition Vent
Outlet Split
Vent
Manual
Pneumatics
B