Rugged Zirconia analyzer for ppm or % Oxygen measurements in combustion & inert gas.

The 8870 is an extractive Zirconia Oxygen analyzer that is typically employed for O2 trace measurements in pure gases (typical in technical gas production industry) or in heavy duty applications thanks to an extremely rugged sensor.


Measurable Gas

Oxygen [O2]

Main Features


Extreme Roughness

  • No inner moving parts
  • Installation position and vibration don’t alter the accuracy and stability of the measure
  • Insensitive to ambient temperature variations


High Performances

  • Inner reference air that eliminates the effect pf barometric pressure variations
  • Extremely fast response time
  • Excellent long term stability
  • Available as 4-20 mA transmitter or combined with a powerful microprocessor-based control unit


Easy Maintenance

  • Modular construction
  • Fast access to the inner PCB just unscrewing the AISI cover


European Compliance

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


Accuracy with control unit: ± 1% of span or ± 1 ppm (whichever is worse)
transmitter: ± 2% of span or ± 0.05% O2 (whichever is worse)
Repeatability ± 0.5% of span (short term).
Linearity better than ± 1% of full scale
Response Time Initial < 0.1 sec.; 90%: < 1 sec. (with max. 300 cc/min. flow rate)
Drift Zero: max. ± 1% of span per week. Span: negligible
Ambient Temp. Influence max. ± 0.06% of reading per °C
Atm. Pressure Influence Free vent: no influence – Pressurized vent: ± 0.1% per hPa
Flow Rate Influence less than 0.3% of span over flow range of 100 to 200 cc/min.
Line Voltage Influence max. 0.02% of span, for each 1% change of power voltage.
Gas Interference combustible gases + O2 reduce the measure
Sample Requirements Sample Flow Rate: 100 ÷ 300 cc/min.
Pressure: 3000 Pa minimum (with filter and flow meter).
Reference Requirements Dry and oil-free instrument air at Flow Rate: 100 ÷ 200 cc/min. (max. 500 cc/min.)
Range Refer to ordering information
Output Standard 8870 sensor output: logarithmic 50 mV/decade functioning as input of control unit that operates calculation, linearization and retransmits the isolated output current.
Transmitter version: 4-20 mA proportional to ordered range; max. load 500 Ω (or 350 Ω with galvanically insulated module)
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
Relative Humidity 90% maximum.
Operation Temperature -10 ÷ +50°C (14 to 122 °F).
Temperature controlled at 700°C
Storage Temperature +70°C (158 °F) max.
Power Requirements 22 ÷ 30 Vac, 200 VA from dedicated power supplier.
Pneumatic Connections Sample IN, sample OUT, reference air: 1/8” NPT-F
Wiring Connections N°2 cable glands for cables 10 ÷ 12 mm


Gas production industry (purity monitoring of N2, Ar, He, CO2)

Air Separators

Nitrogen Generators

Heat treatments


Welding Gas

Combustion Gas

Endothermic Generators

Any application for ppm or % O2 measurement in inert gas or combustion gas



Sampling System

The 8870 needs an external sampling system able to deliver an almost clean sample gas to the analyzer at the proper temperature, pressure and flow rate.

ADEV has a wide experience in process and can provide the 8864 analyzer combined with a sample and condition system designed for the specific application requirements. Contact us for details

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