8
(2) Piping diagram
Shown next is an example of the configuration for measuring three components. (When using
Zirconia O
2
analyzer)
Gas analyzer
(ZRF)
Sample gas outlet
Arrange so that sample ga
outlet is at atmospheric pre
Sample gas
Sample gas inlet
Flow meter
Change
-over
valve
O
2
N O
S O
2
(Span calibration gas)
A i r
(Zero calibration gas)
3.3 Sampling
3.3.1 Sample gas condition
(1) Remove all dust included in sample gas by means of a filter. Use a filter capable of eliminating
dust particles of 0.3
µ
at the final stage.
(2) The dew point of sample gas must be lower than the ambient temperature to prevent accumula-
tion of drain inside the analyzer. If water vapor is included in the sample gas, then feed the gas
through a dehumidifier to lower the dew point to around 0
°
C.
(3) If SO
3
mist is included in sample gas, then use a mist filter, cooler etc. to exclude the mist. The
same applies if other kinds of mist are included.
(4) Note that if strongly corrosive gas such as Cl
2
, F
2
or HC
r
is included in sample gas in a large
amount, it will shorten the service life of the analyzer.
(5) The sample gas temperature should range from 0 to 50
°
C. Be careful not to introduce a high
temperature gas directly into the analyzer.
3.3.2 Sample gas flow rate
The sample gas flow rate should be as follows.
Provide a flowmeter as shown in the preceding diagram to measure the flow rate.
Standard type
0.5
r
±
0.25
r
/minute
Sample switching type
(1
r
+1
r
)
±
0.1
r
/minute (sample gas+reference gas)
Flow differential type
(0.5
r
+ 0.5
r
)
±
0.25
r
/minute (sample gas +reference gas)
