UV/IR Detectors for Flame Detection - Principles of Operation

Optical flame detectors have multiple applications in a variety of hazardous environments, ranging from industrial heating and drying systems, industrial gas turbines, to petrochemical oil and gas facilities. They can reduce the risk in a given environment by quickly detecting an unwanted flame. Therefore, they are more reliable, especially in outdoor settings, where they can respond faster to the presence of a flame than a heat or a smoke detector would.

A UV/IR flame detector consists of ultraviolet (UV) and infrared (IR) sensors that are joined together in a single apparatus. UV sensors work by detecting the UV radiation emitted by the flame and are sensitive to a wide range of flammable fuels including hydrocarbons, sulfur, hydrazine and ammonia.

The main radiant emission band for hydrocarbon fueled fires ranges between 4.3 and 4.4 microns, it is an infrared emission that the IR sensors can detect with ease. What enables the emission to be detected by the IR detector is the energy released by the burning of the CO₂ at a resonance frequency of 4.3 microns.

The ultimate benefit of having UV and IR sensors combined in a single device is that they share the same alarm source – a real hydrocarbon fire. As mentioned, each individual sensor operates separately, but adding advanced signal processing algorithms enables the combination of the two sensors to deliver outstanding flame detector performance to a wide range of flammable liquids, gases, and volatile solids. At the same time, the UV or IR sensors can individually provide enhanced false alarm rejection.

Additional benefits delivered by MSA’s UV/IR flame detectors include continuous self-testing of all optical surfaces, using our Continuous Optical Path Monitoring (COPM) system, and a wide range of configuration and diagnostic options.

World-class UV/IR flame detectors are one of the several useful fixed fire and gas detection instruments available from MSA. Flammable and toxic gas sensors can be used in combination with the improved system provided by MSA in order to achieve the ultimate life safety and facility fire protection.

This information has been sourced, reviewed and adapted from materials provided by MSA - The Safety Company.

For more information on this source, please visit MSA - The Safety Company.