330 Thermal Conductivity Detector (TCD)
Theory of operation
6 of 24
Jun 2001
Detectors
Agilent 6890 Gas Chromatograph Service Manual
switching valve that switches paths through the TCD cell several times a
second. The switching valve oscillates between two flowpaths, one for each
channel of the TCD cell. The makeup gas line sweeps past the end of the
column and carries the column effluent into the TCD cell.
Figure 330-5 Manual TCD flow diagram
Vent
Pressure
regulators
On/off
solenoid
valves
Restrictors
Reference
switching
valve
Reference gas
Makeup gas
Makeup flow