Yokogawa Multi Channel Oxygen Analyzer System ZR22/AV550G - Manual (Page 68)

IM 11M12D01-01E 4-2
The following outlines some points to note regarding the piping for this system.
• Install a stop valve through a nipple on the calibration gas inlet of the detector.
Note: The stop valve should be connected directly to the detector. If any piping is
present between the detector and the stop valve, condensation may develop in
the pipe, causing damage to the detector by rapid cooling when the calibration
gas is introduced.
• When a high temperature detector is used and the pressure of a sample gas is negative,
connect an auxiliary ejector on the sample gas outlet of the high temperature probe
adapter. (See Figure 4.3 in Subsection 4.1.4.)
• When a high temperature detector is used and the pressure of a sample gas is 0.49 Pa
or higher, it is recommended that a throttle (e.g., needle valve) be installed on the
sample gas outlet of the high temperature probe adapter. (See Figure 4.4 in Subsection
4.1.4.)
Note: This is to lower the temperature of a sample gas below 700
ЊC. When both the
temperature and the pressure of a sample gas are high, the temperature of the
sample gas may not fall below 700
ЊC before the gas reaches the detector. On
the other hand, the temperature of a sample gas may drop too much and thus
condensation develops in the high temperature probe ejector. During wintertime,
it is recommended that the probe adapter be protected with an insulating
material to prevent condensation.
• When a high temperature detector is used and blowback is required to eliminate dust
accumulating in the probe of the high temperature probe adapter, air supply piping for
purging should be installed.
Note: If a sample gas contains much dust (e.g., in recovery boilers or cement kilns),
the probe is more likely to become clogged. To eliminate this dust accumulation
using air pressure, piping is generally installed from an air source only when
cleaning is performed. Some cases, however, may need a permanent installation
of the blowback piping. See Subsection 4.1.5 for the installation of blowback
piping.