Abstract: A carbon dioxide scrubber device for use in a closed or semi-closed breatg gas circuit in an underwater breathing apparatus having a low rate of gas flow includes a canister having a plurality of spaced, coaxial walls that are heated by associated helical water flow heat exchangers and define axial gas flow chambers in which particulate carbon dioxide absorbent material is confined in contact with the heated walls. The heat exchangers are served by common supply and drain lines through water flow controlling connectors having flow dividing and uniting orifices.

Abstract: A carbon dioxide absorbent cannister in underwater breathing apparatus of e forced recirculation type. The cannister includes a plurality of stackable condenser elements that serve to cool exhaled gas of high relative humidity so that water, necessary to the desired carbon dioxide removing reaction, is condensed from the gas. The condenser elements are characterized by a plurality of radial, blade-like legs, the outer ends of which are in heat transfer relation to the cannister wall, and by a conical diffuser disc that serves as a heat sink.