YOKOGAWA ZO21DW, User Manual, Page: 14 / 39

<3. PIPING>
3-1
IM 11M03A02-00E
3. PIPING
This chapter describes the line - installation procedures for two typical system configurations of
the zirconia oxygen analyzer using the ZO21DW detector.
CAUTION
• 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.
System 1 : Instrument air is used as the reference gas. Calibration is carried out manually with
the portable ZO21S standard gas unit. The zero gas and span gas (air) are supplied
from the standard gas unit to the detector by connecting the tube only when it is
calibrated.
System 2 : Instrument air is used as the reference gas. This instrument air is also used as the
span gas in calibration. The zero gas in calibration is supplied from the zero gas
cylinder.
System 3 : Basically the same as system 2. However, calibration is carried out automatically with
the converter which has a calibration-execution command function.
3.1 Piping for System 1
The piping in System 1 is illustrated in Figure 3.1.
~
~
Model ZO21S Standard gas unit
EXA ZR402G
ZO21DW Zirconia Oxygen
Analyzer, Detector
Model ZR402G Converter
Stop valve
Calibration gas
F3.1E.ai
100 to 240 V AC
100/110/115
200/220/240 V AC
Contact input
Analog output, Contact output
Digital output (HART)
Instrument air
Air Set
Signal
(6-core shield cable)
Heater (2-core)
Reference gas
Needle
valve
flowmeter
Figure 3.1 Piping for System 1
Piping in System 1 is as follows :
• Place a stop valve through a nipple at the calibration gas inlet of the detector, and mount
a joint for a ø6 × ø4 mm soft tube at the stop valve connection hole of the inlet side (see
Section 3.1.2). The tube is to be connected to this joint only during calibration.