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COMTEC® 6000 The World's First InSitu O2 & COe* (Combustibles) Analyser

Continuous Gas Measurements…
Greater Measuring Accuracy…
Lower Maintenance Costs…
Reliable Measurement…


The Ga2O3 sensor measures not only CO but also all other combustibles. The volume of this combustibles is been indicated in relation to the value of CO. Therefore the sensor measures COequivalent.

COMTEC® 6000 is a totally new and unique InSitu Oxygen & COe (Combustibles) flue gas and process gas analyser. The innovative combustibles sensor pioneered and developed by ENOTEC (patent pending), combines with its world-proven "leak-proof" Zirconia Cell technology to produce the worlds first InSitu O2 & COe analyser. 


System Configuration of COMTEC 6000 for the Measurement of Oxygen and COe

Fig.  System Configuration of COMTEC® 6000


Both measuring cells, (O2 & COe), are actually located inside the process measuring actual real-time values without the need for sampling, conditioning and expensive hybrid systems. The COMTEC® 6000 probe simply installs directly inside the duct for direct & continuous dual readings of Oxygen & COe present. COMTEC® 6000 can easily be installed as standalone instrument or as a retrofit upgrade to an existing system. It's designed to be maintenance free, with minimal calibration requirements, and completely user-friendly operation.

Features of the COMTEC® 6000 Analysing System:

Both measurements completely InSitu – in the process

Versions available for Installation in Safe or Hazardous locations

Ideal for all fuels: Coal, Oil, Gas and Waste Products.

Easy installation & calibration.

Measuring Range:
Oxygen: 0 - 2 %O2 to 0 - 25 % O2 (other on request)
e: 0 – 500 ppm COe to 0 – 10,000 ppm COe (others on request)

High Accuracy:    
+/- 0.2% of reading

Twin (O2 & CO) LCD SME5 electronic simultaneous displays.

Dual 4-20mA isolated outputs for O2 & Combustibles

Fully field serviceable & repairable


Fig. Display of the COMTEC® Electronic Unit

The Measuring Principle of COMTEC® 6000

The COMTEC® 6000 measures the net concentration of O2 and COe (combustibles) in the flue gas of combustion. The water content existing in any flue gas and which has an influence on the actual O2 concentration is taken into account in this wet measuring process.

Measuring principle of the ZrO2-sensor for O2 measurement

The EMF (electrical motive force) produced by a temperature-stabilised Zirconia cell indicates the amount of oxygen concentration. Measurement is made direct and InSitu, i.e. the measuring cell is inside the flue gas duct at the end of a probe in the middle third of the gas stream.

The measuring cell consists of a small zirconium-oxide disc, which is coated with porous layers of platinum on both sides and soldered with a gas-tight seal into the end of a steel tube cell holder.

The temperature of the measuring cell is stabilised by a built-in heater whose temperature is kept constant by a temperature controller. At a constant temperature the mV-output of the cell is equal to the Nernst equation.

Schematic diagram of the Oxygen and COe sensors inside of the COMTEC measuring head

  Fig.  Schematic diagram of the COMTEC® measuring head

The reference gas (Instrument Air) is clean, dry and oil-free air (20.95% by volume O2). When different oxygen concentrations occur between measuring and reference side of the electrochemical cell, there is a migration of oxygen ions from the higher to the lower partial pressure side. The mV output signal of the cell is inversely logarithmically proportional to the oxygen content of the process gas. The reduction of oxygen content in the process gas causes the mV signal of the measuring cell to increase. Air on the process gas side, the ZrO2-cell generates approx. 0 mV ± 5 mV (cell constant) and with 2.1% O2 approx. + 50 mV (rise of the characteristic line or decade voltage).

Measuring principle of the Ga2O3-sensor for COe measurement

In general, a metal oxide sensor consists of an active layer, which resistance changes when exposed to the gas being measured. This unique semiconductor gas sensor is operated at high temperatures approx. 750°C. Ga2O3 sensors show faster response and recovery times and lower cross sensitivity to humidity than other sensors. Additionally, Ga2O3 based sensors show stable long-term sensor properties even in flue gases containing of sulphur and dirt e.g. found in fuel oil burners. Furthermore, the sensor has an excellent performance and measurement repeatability.

The benefits of the Ga2O3 cell compared to other materials are the physical and electronic characteristics of the material. Compared to other commercially available metal oxide sensors, Ga2O3 sensors provide a series of unique product features:

Ga2O3 sensors do not require any pre-aging or conditioning as some other metal oxide sensors. They are completely stable from “first use” and measure accurately within a few seconds from start up.

Ga2O3 sensors show faster response and recovery times than other comparable sensors.

They are almost insensitive to humidity changes.

The selectivity and sensitivity can be controlled by the use of catalytic filter layers.

Ga2O3 sensors have excellent manufacturing characteristics that produce consistent performance for the sensor resistance and operating sensitivity.

Ga2O3 sensors are also stable in atmospheres with low O2 concentration (< 0.1 Vol %).

Technical Data of COMTEC® 6000


see dimension drawings for probe and electronic unit

Mains voltage:

230 V/50  to 60 Hz tolerance +/-10%
115 V/50 to 60 Hz tolerance +/- 10%

Power consumption:

400 VA during heating up
100-200 VA during operation

Series fuse recommended:

10 A

Flue gas temperature:

< 600°C
< 1400°C with gas cooling tube

Ambient temperature:

-20 °C to +55 °C
other temperatures on request

Immunity from disturbance:

European low voltage general directions:
EN 50081-2: July 1993                   
EN 50082-2: March 1995     

Relay outputs: floating:

230 V~ 5 A resistive load

Resolution of A/D converters
in the active measuring range:

14 Bit + sign

Analogue input of thermocouple: 

Re:    >900 kilo Ohm

Temperature compensation:


Signal outputs 0/4 to 20 mA:

Load max. 500 ohm, potential-free

Response time of mA output:

< 200 ms


LCD, LED-illuminates, 240 x 64 points, graphic display


RS 232, RS 485, bus compatible

Measuring Range:

Oxygen 0 - 2 % O2 to 0 - 25 % O2 (other on request)
COe (Combustibles): 0 – 500 ppm COe to 0 – 10,000 ppm COe (others on request)

High Accuracy:    

  +/- 0.2% of reading




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