The P1SS Rebreather
Posted By Duncan Price on 4 July 2003
There were smiles on everyone’s faces when I slipped into the water for the first ever dive on my homemade rebreather. For one thing the device looked like a vacuum cleaner with its scrubber made out of a piece of yellow plastic gas pipe and a counterlung made from a car inner tube. The smiles turned to laughter as the diver emerged a few minutes later with the rebreather in two pieces, counterlung in one hand and the rest of the unit – leaking an alkaline solution – in the other. Back to the drawing board...
Before going any further it should be stressed that making your own life support apparatus is very hazardous. Messing around with rebreathers can leave you looking stupid, dead or both. Futhermore, it might not actually save you any money. Look upon it as a form of adult entertainment. My closed-circuit rebreather is not, however, a toy and has seen some useful service.
Of course, rebreathers are not new, having been around for over a hundred years. The Italian Navy caused great consternation to the Allied forces by scootering up on ships and placing limpet mines on them. The British copied them and these early rebreathers fell into the hands of the Cave Diving Group who used them in places like Wookey Hole as a means of exploring underwater caves. Some of my friends had rebreathers (both homemade and commercially available units like the KISS and Inspiration) and I wanted one. The easiest place to start was to build a simple pendulum style oxygen rebreather for shallow water diving and also for decompression. With no means of monitoring the partial pressure of oxygen one is breathing it is important to purge the loop of air before using. Furthermore, on pure oxygen one’s depth is limited by considerations of oxygen toxicity when are the diver descends. A practical limit for such devices is 6 m. A problem particular to pendulum rebreathers is that the space between the mouthpiece and the scrubber is not cleaned of carbon dioxide. By fitting a power inflator with a bayonet on/off switch I could breathe from this and add oxygen ahead of the dead space thus sweeping any carbon dioxide back into the scrubber. The design is hardly original but it is surprisingly effective.
Before I go any further I should add that I only ever dive in caves or mines. All the testing of my creations has been done underground. It’s a steep learning curve...
- Bookmark with :
- what are these?
