Safeguard Analytics Model SA-5100-CH4 is an infrared based gas sensor designed to continuously detect and monitor combustible hydrocarbon gases in ambient air. Hydrocarbon gases are detected and measured using the Non-Dispersive Infrared Radiation absorbance technique as a source signal.
SA-5025 infrared gas detection sensors consist of a light source and a dual channel pyro-electric detector mounted in a common optical chamber with an external retroflector to provide an open gas sensing chamber. Each dual channel detector is fitted with two optical filters. One channel function is as a reference detector and is fitted with a filter where there are no particular gas absorbance lines. The other channel functions as an active detector and is fitted with a filter that lets through IR light in the wavelength of the target gases – Hydrocarbons typically absorb in the 3.25-3.4 micron. As gas enters the optical chamber less of the source radiation reaches the active detector while the reference detector is unchanged. This differential in light reaching the pyro-electric detectors is the measurement signal.
Each SA-5025 is calibrated at the factory and needs no routine field calibration. It requires only a periodic bump test and cleaning of the windows. Re-zeroing to ensure dependable performance is easily accomplished through the MODBUS serial connection.