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Combustible

​R.C. Sytems Combustible Gas Detectors feature both the Catalytic Bead and Infared Sensor.

The Catalytic Bead ("catbead" or "pellistor") sensor consist of a "reference bead" and an "analytic bead" wired into a Wheatstone bridge circuit. Catbeads burn a small amount of gas on the analytic bead which causes it to get hotter, increasing the resistance and voltage drop which creates an imbalance of the bridge circuit proportional to concentration.

The Infrared (IR) Sensor utilizes band pass filters to pass an analytical and a reference wavelength of IR light through a volume of the gas. The measurement is possible because some target gases absorb very specific wavelengths of IR light. Both the reference and analytical wavelengths are passed through the gas measuring path and reflected back onto the IR detectors. The presence of target gas will reduce the intensity of the analytical beam but not the reference beam similar to the way smoke affects visible light. The reference detector monitors the intensity of the two infrared sources and automatically compensates for loss of signal due to dirty optics or source aging.

 
Acetylene
Butane
Ethane
Ethanol
Ethlyene Oxide
Hexane
Hydrogen
Methane
Pentane
Propane
Propylene