Closed-circuit positive pressure breathing apparatus with pneumatically operated storage chamber

Claim 1

A rebreathing apparatus for use by a wearer having a respiratory system, which comprises: an inhale/exhale breathing conduit; an exhaust gas scrubber means for removing carbon dioxide from an exhaled gaseous stream and having an inlet connected to said inhale/exhale breathing conduit; a breathing storage chamber including means for varying volume of said breathing storage chamber; a conduit means for providing fluid flow between said exhaust gas scrubber means and said breathing storage chamber; a conduit means for providing fluid flow between said breathing storage chamber and said inhale/exhale breathing conduit; a breathing gas supply tank; a pressure reducer valve having an inlet and an outlet; a conduit means for providing fluid flow between said breathing gas supply tank and said inlet of said pressure reducer valve; a pressure sensor means having a housing in fluid flow communication with said outlet of said pressure reducer valve, said pressure sensor means having a piston defining at least two fluidically separate chambers within said housing, one of said chambers being in constant fluid communication with ambient pressure and the other of said chambers being in fluid communication with said inhale/exhale breathing conduit, said pressure sensor means including means within said housing for reciprocally actuating said piston in response to a change of pressure within said other of said chambers due to a change of pressure within said inhale/exhale breathing conduit, said pressure sensor means having valve chambers in alternating fluid flow communication with said means for varying volume of said breathing storage chamber whereby pressure of inhalation/exhalation drives said means for varying pressure of said breathing storage chamber to increase/decrease pressure, respectively, of said breathing storage chamber.