PerkinElmer Frontier IR, User Manual

Page: 39 / 104

Unpacking and Installation . 39
The Desiccant Indicator
The optical system of the spectrometer is purged at the factory. This protects the beam port
windows (and, once fitted, the beamsplitters) from being damaged by humidity. Replaceable
packs of desiccant keep the optics dry and free of CO
2
.
The top panel of the instrument includes a desiccant indicator, whose sectors change
sequentially from blue to pink as the desiccant becomes exhausted (Figure 11). Change the
desiccant in the instrument when the sector marked 10 becomes pink, but while the sectors
marked 15 and 20 are still blue. These numbers correspond to the approximate % Relative
Humidity in the instrument.
Refer to
The Desiccant Indicator in Detail
on page 61 for more information about the
appropriate action to take if the sectors marked 15 and 20 are pink.
Figure 11 The desiccant indicator
CAUTION
If all three sectors of the desiccant indicator are pink, then you must
change the desiccant.
The instrument optics may be fogged. Do not switch the instrument
either ON or OFF until all sectors are blue.
NOTE: A similar desiccant indicator is fitted in the desiccated compartment (Figure 34 on
page 68). This is used for storing sample compartment windows when not in use.
Pink Blue
Blue