US Patent 9032952 Apparatus having cross conditioned breathing air

A self-contained breathing apparatus includes a tank of compressed air and an associated connector. A coaxial conduit extends from the connector to a face plate which might be used by a first responder. Air from the tank is coupled to the face plate via an internal conduit. Exhaled air from the face mask is carried away via an external conduit that surrounds the internal conduit, at least in part, and insulates the air being coupled to the face plate from ambient temperatures. The breathable air, flowing in the internal conduit also cools the exhaled air in the external conduit prior to that air flushing spaces between protective layers of the first responder's coat.