3 - 5
INZ-TN4ZAFE-E
3.4 sampling
3.4.1 Conditions of sampling gas
(1) The dust contained in sample gas should be eliminated completely with filters. The filter at the
final stage should be capable of eliminating dust of 0.3 microne.
(2) The dew point of sample gas must be lower than the ambient temperature for preventing for-
mation of drain in the analyzer. If water vapor is contained in sample gas, its dew point should
be reduced down to about 0°C through a dehumidifier.
(3) If SO
3
mist is contained in sample gas, the mist should be eliminated with a mist filter, cooler,
etc. Eliminate other mist in the same way.
(4) If a large amount of highly corrosive gas such as Cl
2
, F
2
or HCl is contained in sample gas, the
service life of analyzer will be shortened. So, avoid such gases.
(5) TSample gas temperature is allowed within a range from 0 to 50°C. Pay attention not to flow
hot gas directly into the analyzer.
3.4.2 sampling gas flow rate
A flow rate of sampling gas must be 0.4L/min ±0.05L/min (high speed responce: 1L/min ±
0.05L/min).
A flow meter should be provided as shown in “3.4.5” Example of sampling system configuration.
3.4.3 Preparation for standard gas
Prepare the standard gas for zero/span calibration.
Zero gas
Same as reference gas or as specified.
Span gas
Concentration within 90 to 100% of measuring range (Positive range).
Concentration beyond 100% is inapplicable.
3.4.4 Pressure at sampling gas outlet
Pressure at the sampling gas outlet should be set to atmospheric pressure or equivalent.
