PhotoTJ
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frankzeg once bubbled...
As far as gas supplies go there has been increasing work on using the decomposition of N20 (nitrous oxide) to make breathing air( nitrox really). This material is the stuff they use as the propellant for expelling whipped cream and also in dentist's offices as an anaesthetic. When exposed to certain materials it autodecomposes into nitrogen and oxygen. It also releases a ton of energy. With a RT storage density of 45 lbs/ft^3 and being a saturated liquid at around 700 psia it could make a perfect replacement for compressed gas systems. Decomposition must of course be COMPLETE. This has already been demonstrated and has been patented. The equivalent gas volume of a typical 80 ft^3 tank could be contained in a much smaller volume- and at a completely stable pressure due to the physics. Vessel pressure would be less than 1000 psia and hence much lighter. In this setup so long as pressure does not change you have air- when it starts to drop below saturation it means that all the liquid has been consumed and time is getting short.
This material is also a highly energetic one and for you scooter fans out there it could drive a small turbine before being delivered to the diver. this would eliminate the need for heavy and inefficient batteries and allow near infinite burn times with the present volumes of scooters. Numerous failure modes would also be eliminated. So you would breathe the exhaust from your lights and scooter. A turbine small enough for you to handle the thrust from a linked jet pump would be about the size of a shot glass. Forget about rewinding motors to eek out the best possible performance. Or entanglement with props- just hold ON! This could start a real racing community!
There is also an extensive and building database on the use of rotomolded polymeric lined composite pressure vessels- these are made of graphite fiber overwrapped high-density polyethylene and effectively eliminate pressure cycle limits that force primitive stuff like hydrotesting. You could take one of these tanks to 95% of BURST pressure for say a million cycles without any worries about failure. No corrosion except at small end ports- and that is being attacked too. Typical bottle weighs say 10-20 lbs for a 80 ft^3 replacement- and that is conservative. In effect the design of these tanks elimiinates the entire foundation of the ASME boiler code that has driven pressure vessel design for most of a century. Within 30 years the concept of running a presure vessel at <50% of actual burst because of fear of failure will seem funny. And living with weird buoyancy characteristics that are an artifact of metallic bottle design should be a thing of the past. External weighting systems should allow setting up the Cg & Cb at any reasonable points. Watch for even more use of cheaper non-graphite fibers and non-epoxy matrices with the next generation liquid crystal polymer materials.
Power from N2O autodecomposition also allows for new concepts of removing CO2 aside from primitive chemical absorbers. Think molecular sieve and you have the idea. Also with copious power you can design anticipatory demand rebreathers that eliminate stop and start gas flows that are terribly inefficient and fatiguing. THink continuous flow. Think conditioned and warm gas. Think no more Argon rig and chilly decos. And get rid of that block of plastic in your mouth with all the bulky valving. Near zero mass, high discharge coefficent bladder style valves can act as isolators if desired.
With power to spare that thinsulate will seem akin to seal leather mukluks.
Now are all these bulletproof and DIR? Nope. But it gives you some ideas of what might be accomplished with even present day technology if someone cared to make the effort.
The increasing commercialization of PEM fuel cells with integrated reformers also could spill into this industry since a present PEM can generate like 2kilowatts in a thing the size of a 4 tuna cans. And fewer bubbles to boot. The power thing could follow this trajectory as well.
As for exposure suits the concept of sewing things together is already antiquated for anything people have to really rely on. Ultrasonic welding of net shape fabric is probably inevitable. I've already got a folding kayak without a single stitch in it ( on primary seams that is). The technology is already in some drysuits and bladders- expect to see more applications.
For lights expect more use of high power LED arrays to replace HIDs. There is some potential to also emit certain wavelenghts that pass though water more than others- a special mask could allow improved vis in otherwise murky conditions.
If power is available and with a really fast computer there is potential for sonar imaging good enough for a diver. Think a sort of multi-sensor fish finder capable of synthesizing 3-d space. After all if dolphins can do it.....
The physiology of narcosis is getting better understood and there is some potential that the protein folding process that seems to be at the heart of anaesthesia could be interrupted. If interested check out the new Xenon anaesthesia systems. If a dense inert gas can induce anaesthesia at STP it suggests that the likely tenuous chemical interaction between anaesthetics and their target neurochemical could be addressed.
If nitrogen or other inerts presently useless for breathing gas are made less narcotic at depth it can be considered for use in oscillating deocmpression systems wherein gases ( say GHe, Ar and GN2) are alternated at depth. Manipulating partial pressures of the independent constituents could allow continuous but controllable sequential deco without changing depth. Complex but could decouple depth control from decompression control to a certain extent.
As for mechanical devices such as regulators there is an increasing trend towards what are called "no-slip-fit" devices which have no surfaces where adjacent moving parts can bind and are much more resistant to contamination induced failure. You can also make them more internally redundant if desired- so your first stage would already be single failure tolerant before it would exhibit an overt failure. They are also a lot easier to clean and have fewer parts in general. They also do not require lubricants which chops the legs out from the biggest attractant of contamination in the system. Certain designs also completely eliminate the venerable dynamic o-ring- probably the biggest failure point in the whole works.
Also this opens some doors for alternate thinking about the reliability of multiple regs with numerous o-rings, hoses, etc- all of which are decrements to system reliability. NSF redundant valve implementation would also change the architecture of a set of doubles significantly.
THere is already a slight trend towards eliminating chrome over brass construction in regs. While attractive to rec divers the titanium and zirconium materials will be seen ( as they already are in the aerospace community) to be not a good idea for high O2 mixes. And they can be a real pain to machine. The likely material of choice is Inconel 718 (or 600 if cheap is better) which is highly corrosion resistant, strong as hell and readily machined and welded. It is also readily available. Eventually the lower pressure N2O system which does not really need a knock-down first stage could supplant metals entirely.
And if someone doesn't make a practical underwater comm system that doesn't cost the world soon I am going to be really pissed! There has got to be a away to use those sounds I can make in my reg into real, hearable language. Like audible "graphitti" maybe.
z
Uhhhhhh,
Riiiight.
