Hollis Explorer User Manual - page 51
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Below is a graph of the data log from a chamber breathing system test
dive. 1.6litres of CO
2
are being fed into the system every minute. The
external water temperature is approximately 4 degrees Celsius. It shows
the thermistor readings on an arbitrary scale, canister remaining percent
prediction and depth in meters. The endpoint of the graph is when the CO
2
levels reach 5 mBar break through.
The thermistor curves at the beginning of the dive, as the canister heats
up, have a different shape to the middle to latter part of the dive. It is
not sufficient to simply look for the position of the hottest part of the
canister. This will give poor predictions of canister duration. The algo-
rithm first normalizes temperature difference data. Then uses a tech-
nique to determine which part of the curve the system is on – begin-
ning, middle or end. It then correlates a look-up of the measured data
into the suitable reference data to determine the canister duration.
The filter should always be kept sealed until required for use. Once
installed, the filter should be changed within 24 hours even if it has not
been fully used through breathing. When installed and being unused,
the EXPLORER should have its breathing loop closed so that external
air does not accelerate the degradation of the filter. However, once open
and used, even if only a little, the filter will continue to degrade and
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