YOKOGAWA ZR202S, User Manual, Page: 19 / 163

<1.Overview>
1-1
IM 11M13A01-04E
1. Overview
The EXAxt ZR Integrated type Explosion-proof Zirconia Oxygen Analyzer is used to monitor and
control the oxygen concentration in combustion gases, in boilers and industrial furnaces, for wide
application in industries which consume considerable energy-such as steel, electric power, oil and
petrochemical, ceramics, pulp and paper, food, or textiles, as well as incinerators and medium/small
boilers. It can help conserve energy in these industries. The EXAxt ZR also contributes to preservation
of the earth’s environment in preventing global warming and air pollution by controlling complete
combustion to reduce CO
2
, SOx and NOx.
The EXAxt ZR Integrated type Explosion-proof Zirconia Oxygen Analyzer integrates both probe
and converter. The analyzers need not use a sampling device, and allow direct installation of the
probe in the wall of a flue or furnace to measure the concentration of oxygen in the stack gas of the
temperature up to 700°C.
The probe uses a high-reliability Zirconia sensor and a heater assembly that can be replaced on site.
The analyzer is equipped with three infrared switches, which enable the user to operate the equipment
without opening the cover on site. Analyzer calibration can also be fully automated and the automatic
calibration unit is provided. Choose the equipment which best suits your needs so that an optimal
combustion control system can be obtained.
Some examples of typical system configuration are illustrated below:
1.1 < EXAxt ZR > System Configuration
The system configuration should be determined by the conditions; e.g. whether the calibration is to
be automated, and whether flammable gas is present and requires safety precautions. The system
configuration can be classified into two basic patterns as follows:
1.1.1 System 1
This system is for monitoring and controlling oxygen concentration in the combustion gases of a
large-size boiler or heating furnace. Instrument air (clean and dry air of oxygen concentration 21%)
is used as the reference gas and the span gas for calibration. Zero gas is fed from a cylinder during
calibration. The gas flow is controlled by the ZA8F flow setting unit (for manual valve operation).
~
ZR202S Integrated type Explosion-proof
Zirconia Oxygen Analyzer
F1-1E.ai
ZA8F
Flow Setting Unit
Reference gas
Calibration gas
Needle
valve
Flowmeter
Instrument air
Air Set
Pressure
reducing
valve
*2
Zero gas
cylinder
Stop valve
or
Check valve
Span gas
Hazardous Area
Non-hazardous Area
Calibration gas
unit case
100 to 240 V AC
Contact input
Analog output, contact output
Digital output (HART)
*1
Figure 1.1 Example of System 1
Note:
The installation temperature limits range for integrated type analyzer is -20 to 55°C.
*1 Shield cable:
Use shielded signal cables, and connect the shields to the FG terminal of the analyzer.
*2 When a zirconia oxygen analyzer is used, 100%N
2
gas cannot be used as the zero gas.
Use approx. 1 vol%O
2
gas (N
2
-based).