PerkinElmer Frontier IR, User Manual

Page: 70 / 104

70 . Frontier IR Dual-Range Systems User's Guide
Purging the Spectrometer
Under most circumstances, you do not need to purge the optical system. However, after
performing any maintenance tasks that involved opening the main cover, you may purge the
optical system to remove water vapor and CO
2
that entered while the system was open.
Purge the sample compartment if you need to make sure that no residual water vapor or CO
2
peaks are visible in the spectrum, particularly when operating in the FIR range.
There are two separate sets of connectors for purge gas lines, one for the sample
compartment and one for the optical system. You can purge with either dry air or nitrogen.
Both remove water vapor; however, nitrogen is preferable because it also removes
atmospheric carbon dioxide.
A typical cylinder of dry nitrogen (or dry air) stores 6.26 m
3
at 1.4
×
104 kPa (220 ft
3
at
2200 lbf/in
2
). Make sure that the gas is free of oil, water, or dirt particles larger than 25 µ m
(0.001 inch).
WARNING
Do not site the instrument in a poorly ventilated area if nitrogen will be
used as a purge gas.
Oxygen depletion in an enclosed space does not trigger a gasping reflex,
and errors of judgment, confusion, or unconsciousness can occur in
seconds and without warning.
WARNING
Do not use a flammable gas to purge the instrument. The spectrometer
contains a hot source, and a fire or explosion will result. Only use clean,
dry, oil-free nitrogen or air to purge the instrument.
WARNING
Never connect the purge tubing directly to a gas cylinder or other high
pressure supply; always use a pressure regulator and set the pressure to
a maximum of 6.9 kPa (1 lbf/in
2
) before you start the flow.
A length of clear plastic tubing (4 mm internal diameter) will be required to transfer the gas
from the gas bottle to the instrument purge connectors.