Piping For System 2 - YOKOGAWA EXAxtZR Instruction Manual

4.2 Piping for System 2

CAUTION
CAUTION
4-6
Piping in System 2 is illustrated in Figure 4.7.
Model ZR22G Separate type Zirconia Oxygen
Analyzer, Detector
Signal
(6-core shield cable)
Stop valve
or Check valve
Heater (2-core)
Model ZA8F flow setting unit
Reference
gas
Calibration gas
Figure 4.7 Piping for System 2
System 2 illustrated in Figure 4.7 requires piping as follows:
• Connect a stop valve or check valve to the nipple at the reference gas inlet of the
detector.
• If a high-temperature detector is used and the sample gas is under negative pressure,
connect an auxiliary ejector to the sample gas exhaust hole of the high-temperature
probe adapter (see Section 4.1.4, Figure 4.3).
• If a high-temperature detector is used and the pressure of the measured gas is 0.5 kPa
or higher, it is recommended that a needle valve (throttle) be used in the sample gas
exhaust of the high-temperature probe adapter (see Section 4.1.4, Figure 4.4).
• This is for lowering the sample gas temperature below 700 C. If the gas temperature is
high and the pressure is also significantly high, the sampled gas temperature may not
reduced below 700 C when reaching the detector.
On the other hand, if the sample gas temperature is lowered too much, condensation
may be produced in the high-temperature probe adapter. During wintertime, it is
recommended that the probe adapter be protected with an insulating material to
prevent condensation (see Figure 4.5).
For the usage of the high-temperature probe adapter, refer to Section 3.2.2.
If the dust sticking to the interior of the high-temperature probe adapter is to be
eliminated by blow-back while using the high-temperature detector, the air feed for
blow-back should also be taken into consideration.
• The probe is easily clogged if too much dust is contained in the sample gas such as in
a utility boiler or concrete kiln. To get rid of the dust with compressed air, the piping
from the air source is connected only during cleaning. Blow back piping can be
installed for dust cleaning as illustrated in Section 4.3.1.
Model ZR402G Converter
EXA ZR402G
~
flowmeter
Needle
valve
Air Set
Calibration gas pressure regulator
Calibration gas
unit case
100 to
240 V AC
Contact input
Analog output, Contact input
Digital output (HART)
Instrument air
Span gas (Same as Zero gas Calibration)
Zero gas
cylinder
F4.7E.EPS
IM 11M12A01-02E