In-situ zirconia oxygen gas analysers

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Zirconia in-situ oxygen analysers are used to measure oxygen levels and combustion control in furnaces and boilers. The gas analysers are used to control the air-to-fuel ratio of burners in a controlled system to ensure an efficient process. This O2 gas analyser is perfect for controlling and optimizing excess air in a combustion. This measurement instrument provides significant fuel savings.

Oxygen analyser: Optimization of combustion efficiency and compliance with environmental standards

In-situ zirconia oxygen gas analysersIdeal for combustion control of boilers, incinerators and furnaces, an oxygen analyser helps reduce CO₂, SOx and NOx emissions while saving your energy.

This gas analyser is specially designed for continuous measurement of oxygen concentration in flue gas and smoke from boilers in power plants, industrial furnaces (crematoria, glassworks, firing) and incinerators.

These zirconium oxide oxygen measurements are used to regulate the air-fuel ratio of burners in a controlled system to ensure optimum process efficiency in an industrial plant.

This instrument is ideally suited to control and optimize the excess air of a combustion. Therefore it allows an important saving on fuel consumption. 

ZFK8 detector

Zirconia Oxygen Analysers Principle



Operating principle of the In-situ Zirconia oxygen analysers

The operation of the in situ oxygen analyser is based on the property of zirconium oxide, also called zirconia, which conducts oxygen ions when heated.

An analyser obtains the measurement of O₂ concentration by detecting the electromotive force generated by the difference in O₂ content between air and the sample gas.


Applications of oxygen analysers with zirconium oxide probe

The ATEX type zirconia oxygen analyser is suitable for combustion monitoring in hazardous areas.
These analysers comply with the most demanding international standards. They are CE, UL, CSA, ATEX and QAL1 certified.

O2 Gas analyser for combustion

Advantages of O2 oxygen analysers

  • Reduction of excess combustion air
  • Saves fuel by increasing combustion efficiency
  • Long life of the combustion plant
  • Quick and easy replacement of the zirconia element
  • High safety level
  1. The converter cuts off the power supply for the detector when detecting a burnout of thermocouples.
  2. The converter also cuts off the power supply at emergency, in response to an external contact input.
  3. The key lock function prevents operational errors.


Why choose an in situ oxygen analyser with a zirconia probe? 

The In-Situ O2 Analyzer with Zirconia probe offers an accurate measurement of ± 1% on the measured oxygen concentration. It is also very stable over time due to its zirconia probe technology. This system is suitable for processes with high temperatures up to 1500°C depending on the type chosen.

This probe is a very reliable and robust instrument, it can be used in the most difficult conditions (dust, smoke, etc.). Its construction with resistant materials such as 316L stainless steel guarantees an excellent resistance to humid and corrosive atmospheres.

The zirconium oxide analyser is equipped with a backlit LCD display for easy reading of results even in the darkest of places.

The transmitter is also equipped with an audible and visual alarm when preset limits are exceeded.

Among the benefits, they offer:

  • Very long sensor life
  • Easily replaceable zirconia sensor type
  • Easy installation: no smoke extraction required
  • User-friendly operation
  • Wide process temperature range
  • No need for a reference air instrument
  • Fast response (4-7 seconds)
  • Predictive and advanced diagnostics
  • IP66 or IP67 enclosure
  • Fieldbus and RS-485 or HART™ communication


In-situ Zirconia oxygen analysers Applications



TargetO2 in incombustible gas
PrincipleInsertion type zirconia sensor
Range0 ... 2 ... 50 vol% O2 (user configurable)
Repeatability±0.5% FS
Linearity±2% FS
Response time (for 90%)4 s ... 7 s
Output signal4-20 mA DC or 0-1 V DC
Contact output6 points, SPST-NO contact: H/L limit alarm, during maintenance, during blowdown, during calibration, analyser error
Contact input3 volt-free contacts: selection from 7 items
DisplayBacklit LCD
CommunicationRS-485 Modbus®or HART™
Optional functionsCombustion efficiency display, blowdown, auto calibration, selector valve, flowmeter
Safety functionsDetecting a break of the thermocouple for heater control in the sensor unit, the analyser stop the power supply to the detector
The power supply to the detector may also be stopped by external input in an emergency
The key lock function prevents operational errors
Converter installationPanel mount or pipe mount
Cable length between convert and detector≤100m
Power supply voltage100-120 V AC or 200-240 V AC, 50/60 Hz



Depending on the conditions of your processes you can combine the modules below

Oxygen gas analyser model selection


Oxygen gas analyser model selection

Select the required modules combination according to the process conditions using below table.


Process conditionsModules selection
Application exampleTemperatureDustTube materialback purgeTube typeTube code (*)Detector type
Gas boiler≤ 600 °C≤ 0,1 g/Nm3SS316NoStandard guide tube631B562-0#ZFK8
Biomass, Oil, Coal boiler
≤ 600 °C≤ 5 g/Nm3YesGuide tube with backpurge631B563-0#
≤ 25 g/Nm3YesDirect tube for high particulate631B673-0#
YesDirect tube for HP with deflector631B677-0#
≤ 1000 °C≤ 0,2 g/Nm3SS310NoDual Flange (DF) Guide tube for high temperature (HT)631B685-0#ZFKH
≤ 5 g/Nm3YesDF Guide tube for HT with backpurge631B684-0#
≤ 25 g/Nm3YesDirect tube for HT and HP631B675-0#
YesDirect tubefor HT and HP  with deflector631B678-0#
Incinerator / Furnace / Glass /
Metal industry
≤ 1300 °C≤ 0,2 g/Nm3KanthalNoGuide tube for very high temperature631B682-0#
≤ 5 g/Nm3YesGuide tube for very high temperature with backpurge631B683-0#
≤ 800 °C≤ 0,5 g/Nm3SS310YesZTA ejector moduleZTA2ZFK8
≤ 1500 °CSiCYesZTA ejector moduleZTA1
Notes(*) The last digit of the tube code is dedicated to the tube insertion length as per below list:
'1' = 300mm'2' = 500mm'3' = 750mm'4' = 1000mm'Z' = special length -> consult Fuji

(1)  In case of very humid gas, keep the flange hot enough to prevent condensation
(2)  In case of highly corrosive gas, please consult Fuji for special materials
(3) If the gas flow is lower than 5 m/s, use ejector module instead of flow tube


How to choose an in situ oxygen analyser with a zirconia probe? 

You need to measure the oxygen concentration of your industrial process? We help you configure your oxygen measurement platform for :

  • Combustion control
  • Safety measurement
  • Environmental monitoring
  • Furnace atmosphere control
  • Inerting process
  • Other industrial process

With the data from this questionnaire, our engineers will select the best combination for reliable and accurate oxygen analysis. Do not hesitate to send us, in writing or in the form of a diagram, on the last page of this questionnaire or as an attachment, any additional information that would allow us to understand the specifics of your process, and thus adapt the configuration of your O2 analysis solution.

Download the Zirconia O2 Analyser Application Questionnaire



In-situ zirconia oxygen gas analysers documentation