Edgetech 2000 Series - Page 27

Model2000 Serie s DewPrime
Dew Point Hygrometers
-----------Installation Procedures------------
R.OW CONTROL
PRESSURE
REGULATOR
(IF REaD)
Fl.t:IN CONTROL BYPASS R.OW (IF REO'D}
INCREASED TOTAL SMoFLE
R.ON FOR FASTER RESPONSE
EXHAUST
Figure2-1. Suggested sampliDg system .
the installation, and the user must ensure that no portion
of the sample line is at a temperature lower thanthe
highest dew point anticipate d If electrical heater lines are
used , it is usually sufficient to connect themto a variable
transformer to adjust the heating level If the sample lines
are long, it may be desirable to wrap them in insulation
to minimize the amo1m.t ofheat required for
preheating . The Senso r temperature must always be
maintained at least 5°C above the dew point temperature
of the gas sample . The temperature ofthe Sensor must
not exceed+ 1 00°C.Heating the Sensor and sample lines
above the dew point of the gas sample does not change
the dew point of the sample .
2.10 SELECTION OF COMPONENTS AT
LOW DEW POINTS
Whenmeasuring dew-points below -l8°C, increased
attention to sampling details must be made as th e dew
point is lowered.
Rubber,neoprene, tygon, andmost plastic tubing are
lm.desirable for use in hygrometer system s as sample
lines from the sampling system to the Sensor. Specifi-
cally, nonhygroscopic tubing,such as stainless steel ,
Teflon, or KEL-F , with a minimum of joints, fittings,
and other plumbing, is recommended. The actual
selection of the sample line material should be based on
2-4