1. Original CPC Box schematicdP
3-way Leak check valve
CPC flow
1 lpm
CPC
rotameter
CPC +drier flow
5-9 lpm f
mfm
Nafion drier
Drier flow
4-8 lpm
manifold co
rotameter f
mfm
To pump co
Critical orifice f
Filter
The following photos show different versions of the CN box.
mfm
Mass flow meter dP
Pressure gauge

2. Version 1: Oldest design
Version 1: Oldest design. Direction of flow for sample (red) and sheath (yellow) air is shown.
Exhaust manifold
CPC inlet flow
CPC MFM filter
Drier MFM filter
CPC Sample MFM
CPC exhaust
Counterflow
Nafion drier
CPC
CPC Drier MFM
Critical orifice for drier flow
Vacuum gauge
Sheath Rotameter
Sample Rotameter

3. Version 2: More recent. Replaced Brooks MFMs with TSI MFMs (serial output).

4. Version 3: Most recent. Removed vestiges of drain bottle tubing loop.