Manual rEvo III
22
3.5 Calibration of the oxygen cells:
For proper using the rEvodreams please read the appropriate manual.
When calibrating the rEvo-cells only pure oxygen should be used. The calibration
should be done at 1 atm.
Assemble the rEvo completely, be sure that both canisters are placed in the
rebreather, packed, and that the breathing hoses are connected. Open the oxygen
cylinder valve slowly.
(Oxygen valves must ALWAYS be opened slowly, to avoid
the danger of oxygen fires caused by adiabatic compression).
Check that the
diluent cylinder is closed.
Place the mouthpiece in your mouth and suck the lungs to a vacuum (i.e. empty):
exhale through your nose. Push the oxygen manual addition valve, inject oxygen until
a light overpressure exists on the rebreather and let the abundant gas flow from the
corners of the mouth. Stop the oxygen addition, and repeat this cycle 2 more times.
It is important to keep the mouthpiece in the mouth during the procedure and take
care that no gas flows back into the rebreather: you need to obtain 100% oxygen in
the loop. Close the mouthpiece after the third cycle and take out the mouthpiece of
the mouth. Open the mouthpiece a little bit again until you see a small slit inside the
mouthpiece: you will notice a small flow coming out of the rebreather: that confirms
the rebreather is injecting oxygen into the loop. If the mouthpiece is left closed, the
pressure in the rebreather will rise and an incorrect calibration will occur (the loop
would be at more than 1 ata). The small flow also indicates that the orifice is not
blocked.
Now the calibration procedure of the rEvodreams can start (see the rEvodream
manual). When the values of the sensors are within the given limits, the calibration
can be successfully completed. A quick flashing of the green LED will indicate this.
Leave the valve of the oxygen cylinder open during calibration. When the calibration
is finished and you do not intend to dive immediately, then close the oxygen valve
must be closed and the loop flushed with air. If the cylinder is not closed, oxygen will
keep on flowing into the rebreather resulting the cylinder being empty after a few
hours !
To check a correct calibration of the oxygen sensors, vent the unit with air (open the
unit, take out the canister on the inhale lung, and expose the oxygen cells to air): the
calibration was correct if the displayed values are between 0.20 and 0.22.
To make adjustments or changes to the rEvodream settings, please read the
rEvodream manual.
3.6 The orifice:
The gas flow trough the orifice is factory set at +/- 0.6liter/min.
It can be useful to do the following measurement (
not during the dive!
). Be sure the
oxygen cylinder is full, slowly open the valve and the slowly close it: the pressure on
the SPG will slowly drop because oxygen is leaking trough the orifice. Mark the time-
interval it needs to get down form 100 bar to 50 bar. You can perform this test every
