Good morning all,
As promised, i'm back to explain my patent-pending water purification survival device.
To help readers understand how it resolves the issues with the prior art, I'll explain how I came up with it...
At the moment, there are only two devices available to the market that will make sea water drinkable:
The Catadyn filter unit- http://www.amazon.ca/Katadyn-2010000-Pocket-Water-Microfilter/dp/B000RZEJPU/ref=sr_1_2/184-2519957-4462141?ie=UTF8&qid=1448728962&sr=8-2&keywords=katadyn+water+filter
And the Aquamate solar still- http://www.amazon.com/Aquamate-Solar-Emergency-Purification-Inflatable/dp/B004TOAELS
Both products have a place; The Catadyn is an excellent product, if a little pricey. But it's not the kind of product commercial operations or military quartermaster are likely to purchase on the basis that it will then sit in a box, bag or life-raft for the next twenty years on the off-chance an incident requiring it *might* occur! The Catadyn therefore is much more likely to be bought by private individuals keen to invest in "being prepared" for their travel adventures.
The Aquamate therefore continues to be chosen by commercial and military operations. It's cheaper (although not by much) and is less likely to be stolen. So it has dominated the military and commercial markets since its invention 60 years ago.
The Catadyn is a superior product in the sense that it is self-explanatory, simple to use, and so long as it isn't abused will do its job perfectly adequately. By comparison to the Aquamate, it is roughly the same weight and size when packed (both units are approximately 1kg in weight and take up about 2 litres in pack volume). But Aquamate has a number of problems...
First of all it must be manually inflated, which expends precious calories. And unless you have an inflator, you're also likely to lose a significant amount of precious moisture blowing the device up to make it ready for use. This at a time when both calories and fluid are precious resources! The Aquamate must also rest upon a flat surface, either upon the ocean or the ground... both of which are likely to be cold. Since a solar still works by trapping heat from sunlight in order to generate evaporation from the contaminated source liquid, setting the device on a cold surface reduces the efficacy of the device (as heat is absorbed by the cold surface). The makers have used insulative materials to minimise this heat loss, but it is impossible to eliminate in a lightweight, compact unit. Lastly, and most alarmingly, any sea swell sloshes the contaminated contents around, splashing them into the freshly-distilled and extremely-precious drinking water. this also leaves salty residue all over the inner surfaces of the unit, meaning it must be decontaminated before fresh water can be produced! At the end of the day, Aquamate, in my humble opinion, isn't worth the investment.
It doesn't bode well for Aquamate, does it? And given the price of both units, they don't exactly make themselves "ideal choices" for supply in numbers to provide employees or service personnel with an emergency back-up should the worst happen.
So I asked myself, how do I resolve Aquamate's inherent problems and undercut the price of both devices enough to encourage quartermasters and commercial operators to buy my device en-masse? Here's what I had to resolve...
One- Inflation is not an option. The unit must be usable right out of the package
Two- I had to get it off the cold ground/ocean surface, preferably to a location where bodyheat can be used to bolster the efficacy without adding to the user's woes (by chilling them)!
Three- I had to eliminate the sloshing of the source liquid.
Four- the unit has to be significantly lighter than prior products, light enough to carry in a pocket.
Five- It has to be significantly cheaper than prior products.
Six- If it can have a secondary function, provide one!
So it boiled down to this.. a Solar Still that is worn on the body.
The solution came to me when I visited a swimming pool. A competition swimmer was wearing a swim cap... and that got my brain working!
If I could make a cap that was made in a supple, transparent material that was stiff enough to create a bulbous cavity above the head, I could both trap bodyheat and/or the sun's energy and concentrate it on a wetted rag, beanie hat or even dampened hair sufficiently to produce evaporation. The clean fresh water vapour would then rise and condense upon the inner surface of the air-cooled shell and run down into a gutter that encircles the lower edge of the cap. By adding an attachment point at the nape of the neck, I will attach a collapsible pouch bottle into which the produce of the solar still cap can drain and be stored for later consumption, detaching and re-attaching as required.
The device will not overheat the wearer, because the process of evaporation, combined with the large surface area of the cap, work to gently cool the head. The only risk to the wearer would be to use the device on cold days where there is little sun. On those occasions, the device may simply be laid over the damp ground/a rain puddle, where it's small surface contact area will prevent heat loss. So long as the outer rim of the device is in contact with the ground (ie sealed reasonably air-tight) and there is sunlight, it will produce fresh water sufficient to keep the user alive.
The elasticated nature of the material means the headband (the inner rim) can fit a wide range of head sizes, or any other object that can generate moisture. For instance, with a little trimming of spines and in taking a slice off the top of a cactus, the cap can then be set over the moisture-laden flesh where it will extract the water and make it available to the user. Just set it up and get on with your shelter-building/hunting etc. When you get back there will be a reservoir of clean fresh water awaiting!
To recap on the issues to be resolved; My design eliminates the requirement to inflate before use. It eliminates the cold surface absorption of heat from the device (in fact it bolsters it by adding bodyheat). It also eliminates the issue of sloshing, by keeping the moisture held in a cloth or in the hair and trapping any running fresh water in a lightweight pouch (which incidentally may also be used to boil its contents over a fire). It is much lighter than either of the other products, conceivably weighing as little as three ounces and should be no more bulky than an A4 padded envelope (when flattened).
Finally, the material I have chosen for this device is clear Platinum Silicone rubber, which can be textured, patterned or coloured to provide light-absorption or a low-visibility function. But the material has another notable property that adds to the potential functionality of the device- Platinum silicone rubber will withstand upwards of 300 degrees Celsius, meaning the device (which is essentially an oblong bowl shape) can be inverted and suspended over an open fire and used to boil any liquid inside. Effectively, the solar still becomes a cooking pot... a very useful item in a survival scenario!
Apart from these handy additional qualities, my device also eliminates the potential for loss of discipline aboard a life-raft where conditions have placed all aboard under extreme distress due to dehydration. The Aquamate will only produce about 8 to perhaps 15 ounces of fresh water on a good day... a "good" day being a very hot, sunny, calm day... the kind of day when everyone bakes! 15 ounces of water among up to 32 souls (the average modern commercial life-raft capacity) is not sufficient for subsistence provision and is almost impossible to ration out and maintain discipline. Whereas if everyone aboard had a Solarcap, they'd be able to secure their own personal supply of water, perhaps 4 to 8 ounces of clean fresh water each day.
I hope, having detailed all this, you'll lend your support, perhaps by encouraging your quartermasters to consider the product as a viable addition to military equipment stocks. I hope to have a working prototype assembled very soon and will be raising start-up funding in the new year.
Thanks so much for your attention and feedback.
Spot on Blackadder... a solar still it certainly is!
