Campbell Scientific TGA100 Trace Gas Analyzer Manual - Manual (Page 101)

Open (or remove) needle valve
Cap this outlet (or remove tee)
Open (or remove) needle valve
Ambient air in (2.5*X slpm)
Sample air in (X slpm)
From manifold outlet
To TGA100 sample inlet
To vacuum pump
Purge dryer
Sample dryer
0.5*X slpm
2*X slpm
Figure 9-4. Two-Dryer Configuration
The PD1000 dryer comes from the factory configured for the split-sample mode. As shown above, some changes must
be made for the two-dryer configuration:
1) The sample flow is set be an orifice or needle valve at the inlet; therefore the sample needle valve on the sample
dryer is not needed. It may be opened completely or removed.
2) The sample dryer's outlet is not split to provide its purge flow; therefore disconnect the sample dryer's purge tubing
from the tee at its sample outlet and plug or remove the tee.
3) Connect the sample dryer's purge tubing to the outlet of the purge dryer.
4) The purge dryer's sample needle valve is not needed. Remove it or open it completely. The purge flow into the
sample dryer must be set by the sample dryer's purge needle valve, which is downstream of the flow meter, and not
by the purge dryer's sample needle valve. This keeps the flow meter near ambient pressure.
The PD625 dryer does not include the sample needle valve, so steps 1 and 4 are not needed when using PD625s in the
two-dryer configuration.
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