DIY project?

[Freedive WI]

I thought that I would pick the "brain trust" of rebreather divers on here for a "possible" project.

Some Australian guys on the freediving list are making their won "rebreathers" for training purposes. They are really Hypoxicators since they have no drive bottles attached to them. The idea is to do some form of altitude training at home, without springing the $10,000 for a hypoxia tent.  :o

Here's a few shots of what they've come up with so far. Any ideas on how to improve it? I'm also wondering how to control the F02 without a drive bottle?

Jon

[rcojr]

Jon
They appear to have a scrubber for removing the CO2 but without a drive bottle of oxygen you will eventually metabolize all the O2 out of the loop and pass out.
The only way I can see to do this is with either a manual O2 add valve or a KISS valve to bleed O2 into the loop. Either one would need an O2 drive bottle.
Bob

[Freedive WI]

I know that they are using it for Interval hypoxic training (IHT), which means that your on it for 5 minutes and off for 5 minutes. You repeat the drill for 30 minutes a session and build up over time.

I know some guys in Hawaii are looking into using the exhaust gas from a Denitrogenating gas belding system- so they could breath 10% nitrox mixes right off of a tank for specified periods of time. It would seem that this kind of system would be cheaper, and easier to put together.

Jon

[Chuck_Northrup]

Jon,

I know there is a decent size RB following in OZ.  In fact many of these guys pursue homebuilt projects so recruiting local talent should not be too difficult.  One of the most resourceful prospects would be Kerry McKenzie  (aka Tubby) his website is:



If they purchase any RB (including surface and “antique” units which make there way on e-bay once in a while) and have a system of monitoring PO2 it would be a simple process.  As long as the unit proves it can sustain positive and negative pressures with out leaks, and you have a system to monitor FiO2  there is no problem 

If you desire to maintain a survivable yet hypoxic situation for longer than a few minutes it means pluming in pure O2 would be most efficient.  You could also run a continuous flow but there would be a lot of playing around with numbers and variance in workload if you were in a say 15-30 minute “exercise session.”  Possible but more involved.

Since the use you pursue is on the surface...and therefore the worst possible scenario is someone falls down and gets a bump on the head I do not mind sharing this.

IN A DIVING SITUATION MODIFYING REBREATHERS WILL ABSOLUTELY KILL YOU!!!!!

So always seek proper training and dive within your limits.

Hope this helps

[Freedive WI]

Chuck,
It sounds like they are all DIY rebreather guys. Some still tech dive and others have given it up to strictly freedive- but are still looking for something to do with all of those spare parts they have lying around.

The simplest thing, from what I understand, would be to just get a Dolphin but not hook up the drive bottle. That way you just sit in a chair and breath from it for 5 minutes followed by 5 minutes off, to let it recycle, and then breath off of it again for 5 minutes. Since this is done on the surface, and not while doing any exercise, there's little chance of falling over- altough I don't think I'd try it with a F/F mask.

I think that someone mentioned getting a Biopack off of ebay and using something like that. Making sure it had some type of 02 monitor would be essential so you know how low your breathing bag is getting and can cycle off for a few minutes.

I just don't know if it's worth buying an old rebreather to work on my freediving.  ???  It certainly is cheaper than buying a $10,000 hypoxic tent, or one of those $1,500 IHT trainers.

Jon