Signal Model AS80 Catalytic Air Purifier

  SIGNAL Instruments USA Microprocessor Control

Advanced Gas Analyzers

2-Year Warranty
Applications Gases Technologies
Model AS80 Catalytic Air Purifier provides an inexpensive source of clean, zero-grade air for flame ionization detectors (FID). The unit removes all hydrocarbons, including methane (CH4), down to 0.1% of original level. Up to 10 FID units can be run from one AS80. The AS80 contains a high temperature furnace containing alumina pellets coated in platinum; this oxidizes all combustible compounds to carbon dioxide (CO2) and water (H2O). The unit can completely remove CH4 at rates of up to 5 L/min at high efficiency and up to 20 L/min at medium efficiency.


Model AS80 is based on the principle of Catalytic Oxidation. Alumina pellets coated in Platinum metal are fitted into a high temperature furnace. The high temperature together with the platinum noble metal oxidizes all combustible compounds to CO2 and H2O. For practical purposes, the AS80 was developed for use with hydrocarbon and carbon monoxide (CO) analyzers. Both trace levels of hydrocarbons (particularly CH4) and carbon monoxide are extremely difficult to completely remove and this makes it difficult to obtain a reliable and inexpensive source of pure zero gas for these analyzers.

FID-based hydrocarbon analyzers require a continuous supply of zero grade air in order to support the flame in the detector. The air required for this flame should be sufficiently free of hydrocarbons to provide a zero reference, and it should remain stable enough to eliminate any low level drift in the detector response.

The most difficult hydrocarbon to remove is CH4 and it is this compound which is found mostly in ambient air (approx. 60%). No type of adsorption or absorption method effectively removes CH4 but the high temperature platinum catalyst will remove CH4 totally. (Model AS80 has been tested up to 600 ppm CH4 in air at 5 L/min flow-rate.) Further, adsorption techniques have a finite saturation level and the higher the level of hydrocarbons the quicker the adsorption chemicals need changing. Thus the Signal Model AS80 Catalytic Air Purifier provides an inexpensive source of zero reference grade air and also gives a completely stable base line to the FID.

Instruction Manual


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