Patent ID: 7810498

Claim:
A system for increasing the storage volume for breathing gas in a closed-circuit breathing gas apparatus used by a diver during an underwater dive, comprising: a first pressure-sensitive valve having first and second sides with said first side thereof adapted to be coupled directly to an inhalation line carrying breathing gas from a gas source to a diver's mouthpiece in a closed-circuit breathing gas apparatus, said first pressure-sensitive valve opening when a pressure in the inhalation line exceeds a threshold as the diver ascends through the water wherein the breathing gas is simultaneously (i) provided to the mouthpiece from the gas source through the inhalation line, and (ii) passed through said first pressure-sensitive valve to said second side thereof; an expandable reservoir coupled to said second side of said first pressure-sensitive valve; and a second pressure-sensitive valve having first and second sides with said first side thereof adapted to be coupled directly to the inhalation line and said second side thereof coupled to said expandable reservoir, said second pressure-sensitive valve opening when pressure in said expandable reservoir exceeds a second threshold as the diver descends through the water wherein the breathing gas is simultaneously provided to the mouthpiece from (i) the gas source through the inhalation line, and (ii) said expandable reservoir.