Life support in small one-atmosphere underwater work systems

Manned submersibles and atmospheric diving suits share a number of characteristics, with the most obvious being the rigid hull structure required to maintain a one-atmosphere cabin pressure in the presence of high external pressures. The rigid pressure hull results in a fixed internal volume that allow a simple, mechanical means of precisely controlling the input of make up oxygen to replace that metabolized by the occupant(s). The field-proven life support hardware described in this article is peculiar to monobaric systems but may have applications in other manned cabin situations where a fixed volume is present--regardless of maintenance pressure. Also briefly described is a state-of-the-art life support monitoring system developed by Nuytco Research Ltd. under contract to the National Energy Board of Canada. The "Biosensor" is thought to have broad application potential in the manned undersea field.