LI-COR LI-7815, Instruction Manual

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Section 3.
Applications of the LI-7815
In this chapter we provide information about using the instrument in field or labor-
atory applications. We cover connecting plumbing to the air inlet, retrieving data,
and other applications.
Flow schematic
During normal operation, air is drawn into the analyzer through the air inlet ( Figure
3-1 below). Air flows through the optical bench and phase adjuster and is exhausted
through the air outlet. In the optical bench, the pressure is drawn down to about 40
kPa. When the instrument is powering down, air is circulated in a closed loop
through the desiccant to ensure that air remaining in the system is free of moisture,
preventing condensation when the instrument is powered off.
Figure 3-1. Simplified flow schematic of the gas analyzer. During a measurement, (
A
) air
flows through the optical bench and phase adjuster. During shutdown (
B
), the instrument
purges the optical path of water vapor.
3-1 LI-7815 CO₂/H₂O Gas Analyzer