Operation
3-1
Section III.
Operation
General Description
The LI-610 Portable Dew Point Generator is a completely self-contained
instrument that is used to generate a moist air stream with a known dew
point.
A source of dry or ambient air is bubbled through a condenser block
assembly containing a water bath, whose temperature is precisely
controlled by a series of Peltier thermoelectric coolers. The internal
radiator and fan assembly dissipates the heat generated by the coolers,
providing a self-contained cooling system.
Water and air flow through two distinct paths within the LI-610 to
produce a moist air stream with a known dew point.
Air Flow Through
the LI-610
Air is drawn into the LI-610 through the
AIR IN
fitting on the instrument
back panel. Any impurities are removed from this air stream by a filter
before it reaches the air pump. Air leaving the pump passes through a
flow adjust valve on the instrument front panel, where the rate of air flow
through the LI-610 is controlled (see Figure 3-1).
The air stream then enters the two copper condenser blocks via the
T O
CONDENSER
fitting, where a bubbler stone is used to maximize the air-
to-water surface area, which ensures that air leaving the condenser blocks
is completely saturated with water vapor. Water vapor leaving the
condenser blocks through the
FROM CONDENSER
fitting is split into
two separate air streams, which are supplied to
OUTPUT 1
and
OUTPUT
2
on the front of the instrument. The rate of flow through these outputs is
indicated by two rotameters on the front panel. Flow is divided between
the outputs using the flow control valve on output port #2.
