NDIR sensing.

Since the 1940s Non-dispersive Infrared (NDIR) sensing has become an important, safe, reliable and accurate method for the detection of gases such as CO, CO2, CH4 and various refrigerants. In essence, one version of this equipment, consists of an infrared lamp, a sample chamber or light tube, a light filter and an infrared detector. The IR light is directed through the sample chamber towards a dual detector. One element of the detector is covered by an optical filter that passes light that is absorbed by the gas being detected the other element is covered by an optical filter that passes light that is not absorbed by the gas being detected.

A gas such as sulphur hexafluoride (SF6) is an extremely potent greenhouse gas and therefore leaks to the environment must be minimised. Inorganic, colourless and odourless it does however absorb strongly in the infrared, so NDIR sensors of the type described above are ideal for detection at very low ppm concentrations of this and other important gases.

NDIR technology has now been widely accepted and standardised by gas sensor manufacturers worldwide and our diverse range of robust OEM Gas Sensors and Gas Monitors enables fast, reliable and continuous gas detection which has given Edinburgh Sensors a truly global reputation for accuracy, safety and reliability. Applications are many and including horticulture, brewing, agriculture, process control, biogas, personal safety and indoor air quality.

The Guardian NG NDIR gas monitors from Edinburgh Instruments, typify their commitment to customers convenience and safety, backed by over thirty years of sensor design and manufacturing experience. They are wall-mounted and easy to install, detecting gases from sampling points up to 30 metres away, using the built in sampling system. Monitors are housed in robust plastic IP54 rated enclosures to prevent the ingress of particulates and water and have an integral LCD display with digital alarm set-point controls and password protection to prevent accidental or deliberate change of settings.

The Guardian NG infrared gas monitors provide near-analyser quality, offering continuous sampling, measurement and display of target gas concentrations for either CO2 or CH4 gases, where detection level ranges of between 0 – 3000 ppm and 0 – 100% by volume are required. Data can be easily transferred via an on board RS232 I/F with optional Ethernet I/F and relay outputs for control of external devices. Graphical display of historic readings is also possible over a period defined by the user.

These infrared gas monitor also offer near-analyser quality continuous sampling, measurement and display of CO2 concentrations between 0 – 3000 ppm by volume but from low voltage DC (18-30V) supplies. Like the AC Guardian NG these monitors offer long-term stability plus low maintenance, all part of our commitment to our customers that has helped make Edinburgh Sensors a leader in the field of gas sensing.

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