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1 intake assemblies, Intake assemblies, 18. ap200 intake assembly shown open – Campbell Scientific AP200 CO2/H2O Atmospheric Profile System User Manual

Page 25

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AP200 CO

2

/H

2

O Atmospheric Profile System

4.2.1 Intake Assemblies

The AP200 intake assembly (pn 27693) includes a heated rain diverter, an

inline filter, an orifice, and a mixing volume on a common mounting bracket

with rain cover, shown opened in FIGURE 4-18. The inline filter element, pn

29998, is a 2.5-cm (1.0-in) diameter, PTFE membrane with a 3-micron pore

size. It removes particulates from the air sample that could clog the orifice or

valve.

FIGURE 4-18. AP200 intake assembly shown open

The orifice has a diameter of 0.18 mm (0.007 in) to restrict flow to a

maximum of approximately 247 standard ml•min

-1

at sea level. The flow will

be reduced at higher elevations due to the lower atmospheric pressure. The

nominal ambient pressure as a function of elevation is shown in FIGURE 4-19.

13