Re-breather diving unit with oxygen adjustment for decompression optimization

摘要

A mixed-gas, closed circuit, re-breather diving unit (11), and associated diving system and method, having separate supplies (21, 22) of oxygen and inert gas, arranged to feed a breathing loop (23, 25, 26) in such a manner that, in use, oxygen is fed into the loop (23, 25, 26) as it is consumed by a diver, while inert gas is fed into the loop (23, 25, 26) by a water-pressure-sensitive valve (37) to maintain the loop volume, the unit (11) having oxygen partial pressure (ppO.sub.2) monitoring sensors (41) whereby the ppO.sub.2 is continuously monitored and maintained at a pre-set level below that of the oxygen toxicity threshold, having a depth gauge diaphragm (43) and having carbon dioxide (CO.sub.2) scrubber means (23) within the breathing loop (23, 25, 26), and the pre- set level of the ppO.sub.2 can, once the ppO.sub.2 monitor has been calibrated initially, be reset instantly to another ppO.sub.2 pre-set level prior to a dive, and the carbon dioxide level in the breathing loop (23, 25, 26) can be monitored continuously by optional CO.sub.2 level sensors (45), and outputs of the ppO.sub.2 and CO.sub.2 monitoring sensors and of the depth sensor (46) are transmitted via a telemetry link to a surface-located computer programmed to use such output information, together with time information and dive table data, to produce, in real time, a decomposition schedule.