Piping; Piping For System 1 - YOKOGAWA EXAxtZR Instruction Manual

4.

Piping

4.1 Piping for System 1

CAUTION
IM 11M12A01-02E
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 does not allow
leakage. Especially, if there is any leakage of the calibration gas from piping and
joints , it may cause clogging of the piping or incorrect calibration.
• Be sure to conduct leakage test after installing the 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
piping. Stable analyzing can be conducted when using instrument air.
• 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.
The piping in System 1 is illustrated in Figure 4.1.
Model ZR22G Separate type Zirconia Oxygen
Analyzer, Detector
Signal
(6-core shield cable)
Stop valve
Heater (2-core)
Calibration gas
Figure 4.1 Piping in System 1
Piping in System 1 is as follows:
• Place a stop valve through the nipple at the calibration gas inlet of the detector. Then
mount a joint for a 6 mm (O.D.)
hole of the inlet side (see Section 4.1.2). The tube is to be connected to this joint
only during calibration.
• 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 surround-
ing air.
Model ZR402G Converter
EXA ZR402G
100 to
~
240 V AC
Contact input
Analog output, Contact output
Digital output (HART)
Model ZO21S Standard gas unit
100/110/115
~
200/220/240 V AC
F4.1E.EPS
4 mm (I.D.) soft tube at the stop valve connection
4. Piping
4-1