Absorption filter

Claim 1

An absorption filter for the purification of gas and/or airstreams, especially those containing toxic or radioactive contaminants, said absorption filter comprising: a filter housing having an inlet and an outlet and first and second filter chambers, each charged with a granular absorption substrate, said housing inlet communicating with said first filter chamber and said outlet communicating with said second filter chamber, each filter chamber having transverse gas-permeable walls, said first and second filter chambers being separately chargeable with said substrate, said filter chambers being disposed in series in the direction of gas flow, an intermediate section joining said first and second filter chambers in an air-tight fashion such that the flow is from said inlet through said first filter chamber to said second filter chamber via said intermediate section and exhausted through said outlet; a sensing probe disposed in said intermediate section to monitor the degree of saturation of the substrate in said first filter chamber; a monitoring instrument connected to said probe and responsive to a predetermined degree of saturation of said substrate in said first filter chamber for triggering a warning signal; and a bypass filter section having an inlet connected to said housing inlet and an outlet connected to said intermediate section and filled with an absorption substrate, the length of said bypass filter section corresponding to the absorptive capacity of the filter substrate in said first filter chamber.