In many applications, there is a need to be able to verify a pilot flame status by more than one means. This applies in particular to plants that can flare acid gases in environmentally sensitive areas where a flame out, if undetected, could result in toxic gases being released into the atmosphere causing public alarm or worse.
If we take the pilot thermocouples as the primary means of flame detection, then it is often required to add a second independent flame detection means.
This can be achieved by using a remote infra-red camera sensor that is located some distance from the flare tip. It is carefully aimed at the pilot burners and will pick up the heat emission of the pilot flames.
In this way, the pilot flames are continuously checked and if they should ever fail an alarm is given to the control room.