Environnement AF22e, Техническое руководство, Страница: 73 / 118

Duplicationh prohibited
AF22e
Environnement
S.A
3–39
APRIL 2016
Note about gas generation devices:
For pressurized gas devices, it is necessary to provide an excess system to deliver gas at atmospheric
pressure to the analyzer inlet. The device materials should be neutral for the gas used. When the device
is used in automatic cycle with a cylinder, it is necessary to provide a shutoff solenoid-valve remote-
controlled by the analyzer (refer to Figure 3–3).
External
solenoid valve
control
SPAN INLET
Manifold
Solenoid valve
Needle gate
Double pressure
regulator
Gas cylinder
Vent
ANALYZER
Figure 3–3 – Example of a pressurized gas connection
3.5.1.1. Zero air generation
For check and calibration, zero air generation can be obtained using the following methods:
–
Zero check:
A sufficient quality of zero air is obtained using the analyzer zero air filter (Purafil/activated vegetable
charcoal).
– Calibration:
Cylinder of reconstituted air or zero air generator.
Zero air should not contain more than 0.5 ppb of SO
2
, and be free of contaminants likely to be
measured by the analyzer.