Abstract: A method and system for closed-circuit combined unit respiration, is disclosed. More specifically, an enriched air, multi-use closed-circuit self-contained breathing apparatus for on-demand transition between a powered air purifying respirator (PAPR) mode and a closed-circuit rebreather mode, is disclosed. The system may comprise a carbon dioxide scrubbing canister configured to receive an exhaled gas and scrub carbon dioxide from the exhaled gas when in a closed-circuit mode. A breathing bag may receive the scrubbed gas when in the closed-circuit mode. The scrubbed gas may be infused with oxygen, resulting in an enriched gas when in the closed-circuit mode. A cooler comprising a plurality of heatsink fins may cool the enriched gas and a breathing hose may transmit the enriched gas for inhalation when in the closed-circuit mode. The system may further comprise a PAPR to intake and filter external air for inhalation when in the PAPR mode.

Abstract: A testing apparatus for respirators and a method of using the same. The testing apparatus comprises a piston assembly including a piston movably disposed in a chamber and a motor assembly including a motor operably connected to the piston. The motor configured to move the piston in an exhalation direction producing a simulated exhalation and in an opposite inhalation direction producing a simulated inhalation. An amount of gas in the chamber increases during the simulated inhalation and decreases during the simulated exhalation. The method of using the test apparatus comprises the steps of causing the simulated inhalation and the simulated exhalation to determine whether the respirator meets at least one predefined requirement.