Yokogawa Integral Oxygen Analyzer ZR202 - Manual (Page 61)

<4. Pipomg>
4-1
IM 11M12A01-02E 8th Edition : Jan.13,2012-00
4. Piping
This chapter describes piping procedures based on three typical system configurations for EXAxt
ZR Separate type Zirconia Oxygen Analyzer.
• Ensure that each check valve, stop valve and joint used for piping do not allow leakage.
Especially, if there is any leakage of the calibration gas from pipes and joints, it may cause
clogging of the pipes or incorrect calibration.
• Be sure to conduct leakage test after piping.
• Basically, apply instrument air (dehumidified by cooling to the dew point -20 °C or lower, and
removing any dust, oil mist and the like) for the reference gas.
• When the instrument uses natural convection for reference gas, ambient air near the detector is
used for reference gas; therefore the accuracy of analysis will be affected by ambient humidity
changes or the like. If more accurate analysis is necessary, use instrument air (dehumidified to
the dew point -20 °C or lower, and removing any dust, oil mist and the like) for reference gas.
Stable analyzing can be conducted when using instrument air.
4.1 Piping for System 1
The piping in System 1 is illustrated in Figure 4.1.
~
~
ZO21S Standard gas unit
EXA ZR402G
ZR22G Separate type
Zirconia Oxygen Analyzer, Detector
ZR402G Converter
Stop valve
Calibration gas
F4-1E.ai
100 to
240 V AC
100/110/115/200/220/240 V AC
Contact input
Analog output, Contact output
Digital output (HART)
Signal
(6-core shield cable)
Heater (2-core)
Figure 4.1 Piping in System 1
CAUTION
• The stop valve should be connected directly to the detector. If any piping is present between
the detector and the stop valve, water may condense in the pipe, which may cause damage to
the sensor by rapid cooling when the calibration gas is introduced.
The stop valve should be closed except while the calibration gas is being introduced.
• If a high temperature detector is used (the sample gas temperature is 700 °C or higher), piping
for the reference gas is required. In other cases, piping is required if the air around the detector
is not clean.
• The reference gas should have an oxygen concentration identical to that of fresh air (21%).
• When a high temperature detector is used, the sample gas is vented into the surrounding air.
Therefore, the oxygen concentration required may not be obtained unless an exhaust pipe is
installed.