Air Treater; Air Treater Functional Description - Siemens Maxum II Manual

Valves, Detectors, and External Systems

4.3 Air Treater

4.3 Air Treater
4.3.1

Air Treater Functional Description

To provide clean air for the Flame Ionization Detector (FID), the Maxum II uses a catalytic
device known as an Air Treater (figure 4-8) to remove hydrocarbons from ordinary plant
instrument air. The Air Treater is an independent unit mounted near the Maxum II. It consists
of an extremely hot combustion chamber and a catalyst. Instrument air flows through the
combustion chamber and interacts with the catalyst to burn any hydrocarbons in the air. The
resulting clean air and any formed water vapor are then delivered to the analyzer detector
system.
The FID is an extremely sensitive sensor of hydrocarbons. It uses a flame as part of the sensing
system. This flame burns hydrogen fuel mixed with air. Because the FID is so sensitive, the
air used in the combustion process must be completely free of hydrocarbons. Otherwise noise
appears on the detector signal. For this reason, the Air Treater is used to remove any trace
hydrocarbons.
The combustion chamber of the Air Treater is housed in an insulated explosion proof enclosure.
This enclosure prevents hot surfaces from contacting the atmosphere in the area of analyzer
installation.
The Air Treater is connected to electrical power by means of wiring installed in approved
conduit. Wiring connections are not supplied by the factory and must be made in the field.
The instrument air flows into and out of the explosion proof enclosure through specified flame
arrestors. These flame arrestors are supplied by the factory and are firmly attached to the Air
Treater assembly.
Figure 4-8
52
Air Treater
Explosion Protection Safety Standards
Manual, August 2017, A5E02220442001 Rev 8