Are Gas Detectors explosion proof?
Compur Monitors gas detectors are all designed to operate in hazardous atmosphere, i. e. they are certified to be explosion proof. These approvals comply with ATEX standard and are issued by EXAM. How to avoid an instrument to be a source of ignition, can be achieved with different design strategies. It is important to avoid any potential ignition – be it by a spark, a hot surface or an electrostatic discharge. All these physical phenomena must be avoided by selecting appropriate components and design.
One concept is „pressurisation“ Ex „d“. All electrical parts are installed in a pressure – proof housing, so that even a – very unlikely – deflagration inside this housing cannot ignite the outside atmosphere. In order to achieve this, the active part inside is separated from the atmosphere with a flame barrier. Commonly this a sinter metal, which is porous enough to let gas access the sensing element, but its surface is large enough to absorb all combustion energy, so that no ignition can take place.
Another concept is to design an instrument in protection concept “intrinsically safe”. That means all parameters of the electronic components are selected to be utmost energy efficient. Consequently no part can become hot, not capacitor or inductivity is big enough to create a spark.
Of course the design for the operation in explosive atmosphere must be certified and tested by an independent third party. In consequence not only the instrument itself, but also all manufacturing and quality control processes must be audited and certified.