The R2D 4 liter gas reservoir The R2D comes in a neat carry bag containing:
• 3 adult facemasks - Sm (size 4), Med (size 5), Large (size 6) • velcro chinstrap, mask attachment and cuff inflating syringe • twin soda lime canisters and a gas reservoir • connecting tubing
The self-inflating reservoir has a volume of ~ 4 liters. With the hose and scrubbers and the gas in the user’s lungs there is an initial total volume in the closed system of ~ 10 liters, or about 2 liters of oxygen to be consumed before death.
Triple flexible 2 cm hoses connect the soda lime scrubber can- isters and the gas reservoir to the facemask. This provides unre- stricted airflow, even on deep inspiration or expiration. Two hoses carry the expired air to the scrubber. On inspiration, the gas is returned through the third hose. The hose valves (at the facemask- coupling) maintain a circular gas flow, preventing any mixing of scrubbed and un-scrubbed gases.
The critical improvement of the R2D over the earlier Smith-Hof- sess model DeBreather is the clever use of the velcro chinstrap and the use of the inflatable cuff facemask. The air cuff of the facemask is first inflated with the included syringe, then placed in a comfortable and sealing position. This seal is then maintained even when the wearer loses consciousness.