Environnement AF22e, Technical Manual, Page: 29 / 118

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AF22e
Environnement
S.A
APRIL 2016
2–9
2.4 SAMPLING AND ANALYSIS
The sample is drawn through a Teflon tube with a pump connected to the analyzer rear panel. Dust
protection is provided by the dust filter holder equipped with a Teflon filter diaphragm.
Hydrocarbon molecule filtration
Firstly, the sample to be analyzed is filtered by a HC removing aromatic molecule device. This device
consists of two concentric tubes. The internal tube is made of silicone.
The sample containing HC aromatic molecules flows through the internal tube. The HC aromatic
molecules are transferred by permeation to the external silicon tube. The transfer gradient is from higher
to lower concentration.
The pump generates a vacuum in the external tube. The partial aromatic compound pressure decreases
due to activated charcoal filtration. Molecules are exhausted outside the internal tube.
Figure 2–4 – Hydrocarbon molecule filtration
HC : hydrocarbon