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Water purification in emergencies.

Jock Campbell said:
The device I have designed will desalinate and remove harmful chemicals and bacteria (without filtration).

. . .  My device is small enough and light enough to be carried in a map pocket, will allow the user to generate a subsistence level (or more) fresh water AND be usable as a cooking vessel (if you have the skills to create fire)... essential to ensuring healthy sustenance in the wild.

I get the feeling that your gadget is a "still" - maybe small enough to fit in a pocket (or pouch), but able to go through "evaporation" and "condensation" phases without a direct heat source save for body heat or ambient temperature.  Though I've never had to rely on water distillation in a no duff situation, the use of expedient stills were part of the curriculum on some survival training I've done.  I think that there are a couple of products on the market that claim to meet some of the criteria you are suggesting that your device is capable of.  I've no personal experience with them, but most of what I've heard is that they are not particularly useful.  It will e interesting to see what you propose.
Jock Campbell said:
Hi Bearpaw,  you're quite correct, your bottle will only kill bacteria... and depends entirely upon the availability of strong sunlight.

The device I have designed will desalinate and remove harmful chemicals and bacteria (without filtration).

Lifestraw is a good product Colin, but it is a freshwater filter only.  It cannot desalinate, nor will it remove certain chemicals. Nor indeed will it provide a handy secondary function, as my own design can.

EyeintheSky, certainly it does have application in the domestic and commercial marketplace, but it is equally applicable in the tactical environment, albeit utilised (as all equipment should be) with circumspection to the particular situation.  Put it this way; Any soldier/sailor/airman *could* potentially find themselves detached from their unit and stranded in either hostile or neutral territory without the means of rescue and quite possibly without the bulk of their kit.  My device is small enough and light enough to be carried in a map pocket, will allow the user to generate a subsistence level (or more) fresh water AND be usable as a cooking vessel (if you have the skills to create fire)... essential to ensuring healthy sustenance in the wild.

I'll log in this Saturday and describe how I came to design my product and exactly what it is and how it works.

Thanks guys for your feedback thus far.  MUCH appreciated.


I hope it works out well for you, I know I am being a tad skeptical, but better you get put through a bit of a grinder before you part with your hard earned cash. If your product is doing well some of the US shows like SHOT will give you good exposure and you might be able to team up with another Canadian supplier to share booth costs.
Guys, I'm very impressed with your thoughtful enquiries and insight.  Thanks again for all your feedback, I'll come back in tomorrow to explain things more fully.

Blackadder, I hope you'll be back soon to read my detailed description.

Eye in the Sky, yes, thus far I've had exactly the feedback I'd hoped for.  I hope I can allay your concerns and inspire your confidence in my design.

Catch you all tomorrow.

Best regards,
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!
Here is a Catadyn type filter unit at a more affordable price.  I bought a unit of when it was called Guardian microfilter in 2003.  I have never used it as the expedition I was involved with fell through----but it is light and seems well designed.


That unit will not desalinate seawater, Bearpaw.  Nor will it or the Catadyn filter extract fresh water from soil or plant flesh.
You will get more mileage if you take your idea here: 

Yes----Neither the Catadyn nor the Guardian will work with dissolved salts,... and they will not work with mud or plant flesh.  I was just pointing out that the Guadian is a lot cheaper----I paid $60 for mine.  Website for Catadyn and the one I posted indicate that the filtering functionality of both products are very similar.

I do think your ideas are worth pursuing particularly for it use with salt water.

Thanks guys,

Much obliged MCG, I'll look into that later!

Yeah Bearpaw, I feel our military quartermasters might like the concept I've proposed over filtration units, especially given that it's so light, needs no replacement elements and should be considerably cheaper than the other options.  I reckon I could supply my product (bulk wholesale) for less than $20 a unit! 
Something that can freeze would be nice. Not may people realize that all the fancy filters in the world wont do you any good once they've frozen and all the water filled cells expand and destroy the filtering properties. It also gets kind of expensive when you use your $40 straw once and then cant use it in the winter because it wont filter half the stuff out that it is supposed to.
Good point, Urocyon!

Yes, fine filter systems break down quickly in cold conditions.  That said, you tend to find less pathogens in ground water in colder climes.  But certainly, it should be borne in mind.  Hopefully, most survivors of incidents in colder climates put fire and shelter first, usually by carrying a fire-lighting kit and a cutting tool.  My device could certainly compliment such a set and be used over a fire to boil any suspect water.
Eye In The Sky said:
I hope the feedback was useful, and sounds like it was.  I don't believe there are very many "perfect in all scenarios!" tools and gear out there;  I am interested in your gears ability in salt water situations as an example, because I don't have an 'individual' kit item for that problem.


I've had the beaver shits, it ain't fun at all. I got mine from splashing water while swimming, of all things, so I take my water purification pretty seriously. That said, and building on the above, I have a couple of solutions I use somewhat interchangeably: an MSR filter and drops.

I would add another option if it were cost effective (which this appears to be) and made sense to me (which it doesn't, yet, no pics or youtube to watch) I'm interested.

The attached photo was taken after three days on the Cape Chignecto Trail. The element on the right is the used one and the left is a ready to go element.
As it happens Scott, I've carried these replacement filters and a short length of tubing as part of a survival kit for years- great for most fresh water applications out in the bush. 

But it was after spending time ocean sailing that I asked myself what the available equipment was for those ditched at sea.  And upon discovering the lack of options... and how expensive they were... I started wondering if something could be made to cover all situations and could it be more simpler, lighter, less bulky and less costly than what's already available?  I think I've ticked all those boxes!
So when is the reveal?

Think of us as being from Missouri; we want to see the thing first.
Thucydides said:
So when is the reveal?

Think of us as being from Missouri; we want to see the thing first.


I get that it will keep me from getting the shits, and that I could take it sea kayaking -  ig appeal there; what I now want i to see it, see a short FAQ on it, see someone post a Youtube video of it, see it in MEC so I can question their guys who question these things. Because I won't buy a two cent item unless it's shown and not just told, you dig?

Those boxes need to be ticked next.
Re: "The big reveal".

The mold I require to make the first working prototype is in a queue at a local machine shop.  I hope to have it by the end of January.  Then I can hand-mold the first true-to-manufactured-form models and put them through some tests. 

The whole purpose of this particular exercise was to gauge how a more experienced audience would respond to the theoretical concept, rather than relying on the opinions of friends and family.  But since you asked for something a little more substantial, here's a sketch I made for the patent application...

Note: this is a conceptual sketch and is not an accurate representation of the intended final product.

A- Headband
B- Gutter
C- Shell
D- Collection point
E- Connection nozzle

Description-  The device would be injection-molded (ideally) in transparent silicone rubber (thickness will vary between 1/32" to 1/8"depending upon performance requirements).  The condensed fresh water, having collected on the inner surface of the shell will then run down into the gutter, where it will be encouraged, by gravity and normal movements of the head to the collection point located at the nape of the neck.  The connection nozzle has a simple rubber valve which remains shut if nothing is connected to it, so fresh water will pool in the gutter of the device until you are ready to consume it.  However, by attaching a (purpose made) collapsible pouch to the nozzle, the fresh water may be drained into the pouch to act as a handy reservoir. 

As mentioned earlier, the properties of the silicone rubber allow it to resist exposure to high temperatures, so given the bowl-like geometry of the device, it may be inverted and suspended (by the attached drawstring cords) over an open fire to provide a pot in which food or indeed fresh water, may be brought to the boil.

The patent application is currently going through the international patents process via the WIPO.

So, this captures evaporated head sweat to make potable water? 
Jock Campbell said:
Note: this is a conceptual sketch and is not an accurate representation of the intended final product.

Well, it's a little different than what I had visions of.  Considering that my expectation is that there would have to be some "volume" and "spacing" in order for adequate evaporation and condensation, I thought it may end looking something like this.
LOL... yeah, the very thought of it is kinda comical! But no, there's no need for a huge surface area like that.  :D

The external surface of the device can be finely textured, which will more than triple the air-cooled surface area than if it were completely smooth. The device doesn't need to be any larger than a bicycle safety helmet.