Polytector

®

II G750 Application and Detection Principles

Only 4 % Vol lead to poisoning sym- ptoms, 8 % Vol CO CO
2 DetectionAccuracy and reliability by NDIR technology

LEL monitoring

Protection from flammable gases Most flammable gases are odorlessand cannot be perceived by human senses. The danger of explosion is present, if flammable gases or vapors build up hazardous concen-trations. A spark, a flame, a cigaret-te - and the catastrophe happens. For decades GfG uses the proven catalytic combustion sensors for flammable gases. With this type ofsensor the Polytector II registers allflammable gases simultaneously, even e.g. hydrogen, which generally cannot be measured with infraredsensors.
2 are lethal. Inaddition to this, CO
2 causes oxygendeficiency and the danger of suffo- cation. Human senses cannot per- ceive carbon dioxide, as it is odor- less and tasteless. Only a personalgas monitor provides protectionbefore entering confined spaces, landfills, water treatment plants, breweries, sewers and potash mines. The Polytector II uses the dual beamNDIR (non-dispersive infra-red) technology for reliable and accurate measurement of carbon dioxide (CO world’s smallest EX-proofplug-in IR sensor .

NDIR detection principle

Carbon dioxide (CO
2 ) is characterizedby its absorption of light in certainwavelength ranges. The determina-tion of gas by means of light absorption is as definite as a finger- print in criminology. GfG’s infrared sensor uses the NDIRtechnology for measurement ofcarbon dioxide (CO
2 ).

The advantages of GfG’s cata-lytic combustion sensors: The advantages of GfG’s NDIRtechnology:

•All flammable gases and vaporsare registered simultaneously, even hydrogen, solvents and alcohols.
2 ). Infrared light issent through the sensor chamber. Carbon dioxide absorbs a part of the light in a narrow spectrum range.The remaining light is measured at a detector. The difference betweenthe light sent and received is pro-portional to the gas concentration. Water vapor and other gases, which might be present in the sensor chamber, do not affect the absorp-tion of light in this spectrum range,so carbon dioxide is measured very selectively. At the same time, a refe- rence measurement is done in a wavelength range in which carbondioxide does not absorb any light.This results in high measurement accuracy, which is maintained even with an ageing light source or with a soiled mirror. •4 different NDIR sensors for CO
2 and other gases, •> 5 years sensor life,•wide detection range, •no cross sensitivity for othergases,•longtime stability without calibration.•the