Zirconia Flue Gas Analyser


Designed to measure Oxygen in flue gas for combustion efficiency and fuel saving. Ideal for measurements in post combustion chamber at high temperature typical of incinerators, cremators, heating furnaces, soaking pits and annealing furnaces.

Measureable Gas

Oxygen [O2]

Main Features

Extreme Roughness

  • Wetted parts in ceramic materials (Zirconia and pure alumina)
  • Resistant to corrosion by acid & aggressive substances, to abrasion and to the alternation of oxidant and reducing conditions
  • External flanged installation & protection tube (option) warranty extra protection in case of huge dust amount in the process


Easy to Use

  • Direct insertion into the chimney or post-combustion chamber.
  • Integral thermocouple
  • Possibility to verify the calibration without removing the probe from process
  • Calibration (with air flowing) simply pushing one button on ADV222 control unit


Low Costs of Ownership

  • Really in situ measurement
  • No sampling system required
  • Sensor on the tip and no gas circulation


European Compliance

  • Low Voltage Directive 2014/35/EU
  • EMC Directive 2014/30/EU
  • Directive ATEX 94/9/EC (optional)



The Probe 6801 can be configured for hazardous area classified Zone 1 in accordance to EN 94/9/EC (ATEX) and EN 60079-10.



Accuracy0.1% O2 below 5% or 2% of reading above 5%
Zero Drift± 2% of reading in 3 months
Repeatability± 1% of reading (short term)
Response Timeless than 5 sec. at T95 (with flow rate 2 l/min.)
Probe Head ProtectionIP65
Weight~ 1.5 ÷ 2.5 Kg. Depending on probe length (excluded installation tube)
Wiring ConnectionsN°1 cable gland for cable max. 10 mm and inner terminal strip
Pneumatic ConnectionsReference and calibration air inlet: 1/8” NPT-F
GasOxygen (O2)
Measuring PrincipleZirconium Oxide (Zirconia)
Sensor OutputE.M.F. function of Oxygen concentration
TC OutputE.M.F. function of the temperature
Type of ThermocouplesStandard type B (pt 6 Rh-Pt 30 Rh). In alternative type S
Humidity0….90% non-condensing
Temperature Range600°C to 1250°C
Head TemperatureMax. 130°C
Reference AirDry, clean and oil-free air. Flow rate: 100…200 cc/min.
Control Unit
ADV222 specifications (common to all versions)
Analog Inputs2 x isolated (1 for Oxygen and 1 for Temperature)
Analog Outputs2 x 4-20 mA isolated (1 for Oxygen and 1 for Temperature)
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 ; 0-1000°C **
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 ADcase are selected
**Default ranges 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 ADcase Specification
Weight10 Kg.
Dimensions400 x 300 x 150 mm
DisplayLCD 2.42” OLED. Resolution0.01%
Cable Entrance (bottom)N°4 cable glands PG 13 / 9 / 7
Pneumatic ConnectionsReference and calibration air inlets: 1/8” NPT-F
ConfigurationsADcase-1: Pressure reducer and manual valve
ADcase-2: Pressure reducer and electro valve
ADcase-3: Pump and manual valve
ADcase-4: Pump and electro valve


Annealing Furnaces

Reheating Furnaces

Preheating Furnaces

Soaking Pits


Civil Waste Incinerators

Industrial Waste Incinerators

Hospital Waste Incinerators

Sintering of Metals

Process Heaters

Other combustion processes where flue gas is within temperatures limits (600 ÷ 1250 °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 (E.M.F.) on two electrodes placed in contact with different O2 concentrations (partial pressures), proportional to the temperature in Kelvin degrees (°K) and to the logarithm of the ratio between the two pressures PO2’ and PO2” in accordance with Nernst’s well-known ratio:


E = RT / nF (ln P02’ / P02“)


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

                       F = Faraday’s constant

                       T = Absolute temperature in °Kelvin

                       n = 4