Gas assisted re-breathing device

A re-breathing device for providing breathing gas to a user, the device comprising:

• (a) a pressurized gas source supplying a pressurized gas;
• (b) a mouthpiece providing an interface between the user and an assisted breathing loop;
• (c) a breathing regulator in the assisted breathing loop, the breathing regulator fluidly connected to the pressurized gas source, the breathing regulator generating a variable pressure drive gas and presenting a breathing gas intermediate the mouthpiece and the assisted breathing loop;
• (d) a variable volume chamber in the assisted breathing loop, the variable volume chamber fluidly connected to the breathing regulator to receive and provide breathing gas;
• (e) positioning means for varying a volume of the assisted breathing loop by varying a volume of the variable volume chamber in response to pressure changes of the variable pressure drive gas acting against a variable and position dependent force;
• (f) a loop seal valve in the assisted breathing loop, the loop seal valve fluidly connected to the assisted breathing loop and selected to permit passing breathing gas one way from the assisted breathing loop into a surrounding environment in response to the variable pressure drive gas at a predetermined volume of breathing gas retained in the variable volume chamber;
• and
• (g) the breathing regulator controlling venting of the variable pressure drive gas back into the assisted breathing loop, the drive gas presented to fluid connections between the breathing regulator, the positioning means for varying the volume of the variable volume chamber, and the loop seal valve to control passing breathing gas from the assisted breathing loop to the surrounding environment.