Zirconia Flue Gas Analyser


Self-heated probe, designed to measure Oxygen in flue gas (up to 700°C). Designed to measure Oxygen in flue gas for combustion efficiency and fuel saving in big boilers and power plants fed by Natural Gas, light and heavy oils, LPG, Biomass and Coal.

 Available as a transmitter with 4-20 mA output from the probe head or combined with a control unit / display.


Measureable Gas

Oxygen [O2]


Main Features

Extreme Roughness

  • Rugged materials contacting the process gas
  • Usable in flue gas up to 700°C, either continuously or cyclically
  • Do not suffer damage or deformation
  • Installation and protection tube makes the probe suitable for high dust flue gas, avoiding abrasion and sticking of dirty material.
  • Different types of filter mesh and deflector plate to put against gas flow to limit the dust impact on the sensor:

Ceramic fiber mesh: Suitable for non-sticking dust and moderate flow rate applications

Ceramic mesh: Suitable for high dust, sticking particulate and high flow rate that may generate abrasive effect

Metallic Stainless Steel sintered filter: suitable for highly abrasive dusts and high flow rates inside the stack

No Critical Parts

  • Potentially critical solutions have been avoided such as internal welds, critical couplings and separation of the reference atmospheres from the measurement atmospheres:


Easy to Use and Service

  • Direct insertion into the smokestack or duct
  • Possibility to check the calibration without removing the probe from process
  • All components parts easily accessible and field serviceable.

Sensor assembly replaceable without removal of the probe from its mounting.


European Compliance

  • Low Voltage Directive 2014/35/EU
  • EMC Directive 2014/30/EU



Accuracy0.1% O2 below 5% or 2% of reading above 5%
Repeatability± 1% of reading (short term)
Output Resolution0.01% O2
Response TimeSensor: 0.1 sec. ; Overall system < 5 sec.
Flue Gas Temperatureup to 700°C (on request up to 800°C)
Insertion Length300 / 450 / 1000 / 1500 / 2000 mm
Process ConnectionFlange type
Ambient Temp. InfluenceProbe: max ± 0.005% of reading per °C. External head: max. 0.06% of reading per °C
Atm. Pressure Influence1% of reading per 1% change in ambient pressure.
Probe Head ProtectionIP65
Head Temperature-5°C…+55°C
WeightProbe 300/450 mm: 9 Kg. ; Probe 1000 mm: 10 Kg.; Probe 1500 mm: 11 Kg. ; Probe 2000 mm: 13 Kg.
Wiring ConnectionsN°2 cable glands for cables max. 10 mm and inner terminal strip
Pneumatic ConnectionsCalibration inlet: 1/8” NPT-F
Measuring PrincipleZirconium Oxide (Zirconia). Micro-pod sensor technology with no need of reference air
Humidity0….90% non-condensing
Analog Output1 x 4-20 mA linear output proportional to range; max. load 500 Ω (or 350 Ω with galvanically insulated module) or logarithmic 50 mV/decade *
Ranges0-5 / 0-10 / 0-25% O2 (to select at order)
Diagnostic NV Logical Output (non-valid)Logical Non Valid output from relay free contact. Normally supplied in fail safe condition (triggered relay and closed contact if not in alarm). Can be modified in filed
Power Supply117 VAC ± 10%, 50/60 Hz, 350 VA
*Output from probe when connected to a remote ADEV control unit
Control Unit
ADV222 specifications (common to all versions)
Analog Inputs2 x isolated
Analog Outputs2 x isolated
Output Resolutionbetter than 1x10.000 of FS
RelaysN°2 relays SPDT, 230 VAC, nominal 2A (max 4A) **
Power Supply8...28 VDC ; 9...24 VAC
Ranges0-25% O2 ***
Operative Temperature-20°C…+70°C
Humidity0….90% non-condensing
LedPower supply (blue) - Cumulative inputs overload (red) - TX/RX (yellow/amber)
Serial InterfaceRS485 2-wire (Protocol ModBus-RTU)
Line Impedance120 ohm
Termination TypeExternal
Max Speed57600bps
Max No. of Nodes32
Weight900 gr.
ConnectionsRemovable screw terminals pace 5,08 mm
Conductor SectionMax. 2,5 mmq
MountingDIN rail
***Threshold to be selected at order (factory set) or settable in field by PC with ADEV Easy Configurator or by display if ADbox or ADcaseM are selected
****Default range factory set. Modifiable on request at order on customer specification or by PC with ADEV Easy Configurator
Supplementary ADbox Specification
Weight8 Kg.
Dimensions400 x 300 x 150 mm
DisplayLCD 2.42” OLED. Resolution0.01%
Cable Entrance (bottom)N°4 cable glands PG 13 / 9 / 7
Supplementary ADcaseM Specification
Weight10 Kg.
Dimensions400 x 300 x 150 mm
500 x 400 x 250 mm (with transformer)
DisplayLCD 2.42” OLED. Resolution0.01%
Cable Entrance (bottom)N°4 cable glands PG 13 / 9 / 7
Pneumatic ConnectionsCalibration air inlets: 1/8” NPT-F
ConfigurationsADcaseM-1: Pressure reducer and manual valve
ADcaseM-2: Pressure reducer and electro valve


Industrial boilers using any type of fuel: Natural gas, LPG, light oils, heavy oils, diesel, coal, biomass

Utility Boilers

Recovery Boilers

Low Temperature Incinerators

Power Plants

Cement Kilns

Industrial Furnaces

Other combustion processes where flue gas is within temperatures limits (within 700°C)


Measuring Principle


The measuring principle on which the analysis is based is linked to the use of Zirconium oxide which, at high temperatures, can behave like a solid state electrolyte, developing an electromotive force on two electrodes placed in contact with different O2 concentrations (partial pressures), proportional to the temperature in Kelvin degrees (°K) and the logarithm of the ratio between the two pressures PO2’ and PO2” in accordance with Nernst’s well-know ratio:


E = RT / nF (Lg P02’ / P02“)


Where:           R = Perfect gas constant (8,31 Joule/degree bulk)

                       F = Faraday’s constant

                       T = Absolute temperature in °Kelvin

                       n = 4



The inner sensing element is a based on a proprietary ADEV technology (micro-pod) and features a solid state reference that completely eliminate the need of a reference air flow, making the instrument very easy and practical to use in field.

  • No reference air
  • Sensor on the tip
  • No gas circulation