The different systems that make out my rebreather:
1) The basics:
A case with 2 bottles attached: 5l diluent (gives me some on-board bailout) and 3l Oxygen.
2) The important thing:
The breathing loop consists of an original Draeger Dolphin loop. 2 changes have been made:
- overpressure relieve valve and p-port for injector piece have been switched: relieve is now on inhale lung and p-port on exhale lung.
- A T-piece has been added to accomodate the 3 O2 cells.
3) The technics:
Consists of 2 parts: dilluent and oxygen.
- Diluent is added thru a regular first stage (picture: extreme right), connected with the old ADV of the draeger (picture: second from right), which works just like any other seconds stage. As the original Draeger first stage operates on a higher intermediate pressure as a regular first stage, I had to change the adv's spring for a lighter one. The other 2 hoses on the first stage are for pressure gauge and for wing inflator/bailout regulator.
- Oxygen is added thru a regulator (picture: extreme left) which has been adapted to give a fixed intermediate pressure. From there it goes to the kiss valve (picture: second from left) which provides the loop with a constant flow of oxygen. The valve also contains a shut off and a bypass button. The other 2 hoses on the oxygen first stage are for pressure gauge and oxygen bailout regulator.
4) The electronics:
Nothing special, just a triple 02 meter. No logic inside. And not really fully triple redundant: only one battery, one casing, one cable. All single point of failure's.
5) And the regular stuff:
I use my "old" backplate and wing. The wing has an Air2 as inflator piece, which will also be usable for my on-board dilluent bailout.
How to fit all this toghether:
First put the breathing loop inside the box.
Attach the mechanics to it. Here you see one reason why P-port has been shifted to exhale bag: so the connections to the loop are made at the exterior. Another reason is that this way your gasses which are injected here, first have to pass thru scrubber and inhale lung, before they are measured. This gives the mixture more time to "mix".
add the basic stuff (backplate and wing) on top, and finish connections.
Don't forget the electronics, they just plug into the T-piece.
Here's howe it looks underwater:
You can see I wear separate bail-out at all times ! Dry-suit inflation is also attached to this
Here you see that the alu 5 l is positive, the steel 3 l is negative. I've put 1kg of lead inside the box at diluent side to compensate.
Possible further evolution
- Diluent in steel 3l also, use alu 5l as separate bail out. This would make for a lighter rigging, still ok for the kind of diving I do here in Belgium: wreckdiving on the North Sea, to depts in the 25 - 45 m range.
- shift the oxigen bottel's valve, so that the regulator sits on the inside. Would give a cleaner setup, and the tubings would all be routed "inside" the rig.
- Electronics should become fully tripple redundant, if not better: computer, ECCR, ... I'll keep on dreaming.
- There is place at the bottom for a small bottle for drysuit inflation.