Gas detection system
The Dräger Polytron SE Ex ... DD sensing heads are gas detectors for the continuous monitoring of flammable gases and vapors in the ambient air. The measurement is based on the heat of reaction principle, where a chemical reaction takes place in a catalytic bead (so-called pellistor) inside the sensor.
By this, concentrations of flammable gases can be detected long before they tend to be ignitable, in other words: before they reach the lower explosive limit (LEL).
Honeywell: choosing the right gas detection system. There are many gas detection products on the market that might appear to be the same, but a closer inspection of specification, functionality and features reveals major differences in what products can do and the potential benefits they can offer.