Exhaust gas with a temperature above dew point is intro-
duced into a spiralling gas path with a coated metal surface
of good thermal conductivity. The hot gas radiates its heat to
this metal coating, which is thermally connected to a Peltier
element and a second metal body with cooling ribs and venti-
lation slots. The flow thru the Peltier element creates a heat
transfer from WARM to COLD and this takes the heat from
the metal coating and transfers it to the outer cooling body.
The heat is then released to the surrounding air via a ventila-
tion fan.
Condensation forms when the gas temperature drops be-
low dew point. This moisture drains into the water trap bowl
and is pumped out by a peristaltic pump when the water
reaches a high enough level to link both monitoring elec-
trodes.
The high speed pump allows for enough flow to avoid ex-
cess exposure time between the gas sample and water, so
that drop-out reactions (for example, NO
2
+H
2
O > H
2
NO
3
) do
not occur, which is necessary for measurement accuracy.
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