Info or advice

[Wolfecad]

Hi guys

I want to design and manufacture a small breathing apparatus that is light weight and can be refilled with oxygen once to return to the surface and float on your stomach for abit until the apparatus refills with air then you can dive again would anyone know if this has been done before or if this would be possible I dont want if for scuba diving I just want to increase my time under by a coue of minutes but it needs to refill once I return to te surface would anyone be able to help
Or advice me on how to do this or if someone has already done it

Cheers guys

 

[DevonDiver]

I am not sure how practical such a device could ever be. Here are a few reaons why such a device has never been successfully built before:

1) It wouldn't fill with oxygen... it would fill with air. If you could find a way to fill it with pure oxygen from a brief exposure at the surface, with it all being self-contained and man-portable, you'd get rich very quickly.

2) Boyle's Law describes the relationship between pressure and volume.

....a) If you filled a flexible container at the surface, it would be 'crushed' as you descended, providing a proportionally smaller amount of air as you increased in depth.

....b) If you filled a sealed container at the surface, the internal pressure would remain constant, whilst the external (water) pressure rose. The human lungs would not be capable of 'sucking' the lower pressure air out of the container against the resistance/weight of the water pressing on the chest.

3) The volume of the container (sealed or flexible) containing air would provide a large amount of buoyancy to the diver/swimmer. Displaced seawater weights approx 1.03kg per litre - so you can calculate the buoyancy genereated. The diver/swimmer would need a corresponding amount of added weight in order to descend in the water. However, once the container was 'crushed' by water pressure (Boyles Law again), it would lose volume and, hence, buoyancy. This would mean the diver became very negatively buoyant and would sink quickly and uncontrollably. The 'weight' of water pressing on the diver would be an additional 14.7psi per each 10m descended.

 

[Testudo]

Way to go burst his bubble.

 

[Arubandi07]

Assume, you're talking about a small container, say, pony bottle size, and refilling that with air, not pure oxygen, as your post implies. Theoretically, all you need, would be a pocket-size compressor, operational under submersion, and a modified pony bottle with a separate filling- and outlet-valve.

 

[Arubandi07]

And just to put things in perspective, I have no idea, whether my suggestion is even technically possible, interesting idea to spin around, that's all.

In any case, if such a device existed, I wouldn't use it, goes against my snorkeldiving philosophy, never felt tempted to buzz around with a scooter, either...

 

[g1138]

Don't forget to mention that if you breath said apparatus underwater you'll then risk lung overexpansion on the way up.
Assuming of course if he can get over the "crushing" effect that is.

Way to go burst his bubble.

 

[Wolfecad]

Hi guys

Thank you for the advice I will think about what you have all said by would still like to check it out I dont want it to go to deep like a scuba diver or anything maybe a max of say 5metres or slightly more or even it you stayed on the surface but kept your head under like a snorkel but with no chance if breathing in the water lol

 

[DevonDiver]

Hi Wolfcad,

It'd pay to do some primary research on Boyle's Law and the physiological significance of increased ambient pressure on the thorax versus diaghram strength for inhalation.

Even a small increase in ambient pressure surrounding the body is going to make inhalation a very taxing proposition if the air you are breathing is not correspondingly pressurized. At a 'shallow' 5m depth, you are looking at an additional 7.4psi.

That equates to an increased breathing resistance equal to 7 & ¹/₂ 1lb diving weights for every inch of your chest...!!

Imagine trying to breath with one of these pushing against every square inch of your chest...

Even if you could draw a breath against that level of resistance... the overall workload would pose a significant risk of CO² build-up over a short period of time...which could result in a potentially fatal black-out.

 

[WetBoy101]

I don't know how relative this is to the OP. Maybe more about inventing stuff (or trying) We were at Lake Powell waterskiing. Hit a stick or something an tweaked the prop of my inboard. Being a long way from a boat ramp we took a snorkel and stuck a noodle on the end to extend it thinking we could take the prop off in very shallow water and replace it with the spare. I was less than three feet under water and could not inhale any air.(Pressure, it's amazing!!)

 

[Wolfecad]

Hey Guy's

Thank you so much for all your comments, i will have a look at that law as well.
I live in Perth Western Australia and alot of people out here go snorkling and I just thought if there was a way it would be a good investment, because scuba diving you can only stay down for limit time before you would have to come back up for a new tank and then get the other one refilled. were this you would just surface and then once reloaded you could dive again but as you have all said it might be impossible but were more research i think.

I am just starting my own drafting company and was thinking of idea's really some are quite out there but the way technology is going soon could be reality hey.

once again thank you for all the advice also if anyone needs drawings or parts manufacture or and idea you want to try im all ears, i have the latest in 3D design software and can also get samples ready for bulk manufacturing I have only just recieved my certificate so my website doesnt state an Australian Business Number as yet but soon will. if anyone is interested my website is www wolfecad com
Cheers and any more advice would be greatly appreciated.

Mike