Yokogawa Extractive Oxygen Gas Analyzer TDLS220 - Manual (Page 28)

<5 INSTALLATION AND WIRING> 5-5
IM 11Y01B02-01E-A 4th Edition September 11, 2012-00
5.4 Purge Gas Requirements and Hazardous Area Systems
The TDLS220 Analyzer requires a continuous nitrogen (optionally instrument air) gas purge to prevent ambient
oxygen ingress to the optical path, when oxygen is the measured gas. The flow rate can be minimized as long
as it prevents any ambient oxygen ingress to the measurement optical path. Other purge gases may be used as
long as they do not contain any of the measured gas and a clean, dry, etc.
For hazardous area operation, the same nitrogen purge gas is used to purge the entire analyzer (including non-
optical path sections such as the electronics). Refer to purge diagrams below.
In some applications, Instrument Air (I/A) may be used as the purge gas. Special software configurations must
be set-up under the “Configure” section called “Non-Process Parameters” – refer to software section of this
manual for further details.
The flow rate can be minimized as long as it prevents any ambient oxygen ingress to the measurement optical
path. Other purge gases may be used as long as they do not contain any of
ELECTRONICS
CONTROLLER
FLOW CELL
POWER
HEAT
TRACE
LASER &
DETECT
N2 Purge Inlet
N2 Purge Vent
Figure 10 – Safe Area/General Purpose N
2
Analyzer Purge Schematic
N
2
Purge Inlet
N
2
Purge Vent