Going back to the basics of osmosis:

Water will move across a semi-permeable membrane from areas of higher concentration of salts and/or sugars to less concentrated areas. The “receiving” side of the semi-permeable membrane contains the highly concentrated sugar solution. Since this side of the membrane has a higher osmolarity then the side containing the salt water, the water (since the salt cannot cross the membrane) will pass through the membrane in an attempt to dilute the sugar solution.

Pete

Interesting! So, if I understand correctly, the sugar/salt ratio controls the direction of osmosis?

I've never looked at it from that angle, which is (I guess) a mimic of the biological process.

Rather, I've seen it from the angle of "controlled pressure applied to a membrane" that forces osmosis to the lower-mineral-concentration side. This is the most common industrial application -- from bottled water production to boiler feedwater for power generation stations.

Regarding the product itself, though, I doubt this process could produce a fraction of the drinking water that a pump/membrane system could provide.

Does anyone know the size of this kit packaged? It looks as though it might be a nice alternative to on-person carry for over water excursions where it is impractical to carry a reverse osmosis desalinator in your vest.

There are numerous different products that fit different requirements. Check out the product catalog: http://www.sea-pack.com/images/MantaVenturesProductCatalog.pdf It has conversion times and such.

The LifePack is designed and priced for people that wish to store them at home for disaster preparedness (hurricanes and earthquakes).

The SeaPack was developed for use in an abandonship bag or life raft canister. 9" x 13" x 2"

The X-Pack is the first product design and is used for disaster relief.

The Expedition is designed to produce drink while on the move. Try that with a hand held RO pump.

The HydroWell is made for supporting large groups of people, but it weighs enough that you would need a vehicle to transport it.

None of these products require electricity or pumping. They work by themselves while you are away taking care of something else or sleeping.

X-Packs - 1 filter with 10- 2 oz syrup charges
Individual Weight- 2.75 pounds

X-Pack Resupply - 10- 2 oz syrup charges
Individual Weight- 2.75 pounds

LifePacks - 1 filter with 6-2 oz syrup charges
Individual Weight- 2.0 pounds

SeaPacks - 1 filter with 5-4 oz syrup charges
Individual Weight- 3.0 pounds

Expeditions - 1 filter in bladder with 10-120 mil syrup charges and cleaning kit
Individual Weight- 7 pounds

Expedition with backpack - 1 filter in bladder in a backpack with 10-120 mil syrup charges and cleaning kit
Individual Weight- 9 pounds

Expedition Resupply kit - 10-120 mil syrup charges and cleaning kit
Individual Weight- 5.5 pounds

Expedition Filter kit - 10-120 mil syrup charges and cleaning kit
Individual Weight- 6.25 pounds

Hydrowell Watercan 0- 1 Filter with 20-410 mil syrup charges and a syrup feed tray and 1 accessory kit.
Individual Weight- 37 pounds

Hydrowell Watercan 1-1 Filter in can with 20-410 mil syrup charges and a syrup feed tray and 1 accessory kit.
Individual Weight- 41 pounds

Hydrowell Watercan 2- 1 Filter in can with a clean water collection can and 20-410 mil syrup charges and a syrup feed tray and 1 accessory kit.
Individual Weight- 48 pounds

Hydrowell Watercan Resupply kit - 20-410 mil syrup charges and 1 accessory kit.
Individual Weight- 31 pounds

Hydrowell Watercan Filter kit - 1 Watercan Filter
Individual Weight- 3.25 pounds

You are correct in your statement that these systems can not produce as much as a hand held RO pump. (The HydroWell can produce as much.)

The beauty with these systems is that they do not require pumping, which is why the Coast Guard has them on their planes. The USCG found that most pilots are disabled during a crash and they can't operate a RO pump in that injured state.

People are purchasing the SeaPack and LifePacks because they are so much less expensive than RO pumps that can handle salt. They also do not require pumping or maintenance.

Rick Feineis
Managing Partner
Manta Ventures, LLC
www.sea-pack.com

Yes, it works well.

Please give me a call anytime.

866-314-4824

Rick Feineis
Managing Partner
Manta Ventures, LLC
http://www.sea-pack.com

I developed the SeaPack last year when sailing from the Bahamas to Norfolk, VA. Here we were on a $500,000 catamaran and the captain did not have a hand held RO pump. I asked him why and he said that they were too expensive. I came home and researched other people that cross oceans. 98% of them did not have portable RO systems because they are too expensive.

The SeaPack was developed off of the same concept as the other systems except that it can handle salt water. The other systems can't due to the filter and the level of sugar that is used.

Since there is no pressure to push the water through the filter, these systems can not clog due to turbid (muddy) water.

These have already saved lives over in the Middle East. A military squad was left in the desert longer than planned. They had the X-Packs along and converted their urine into the survival drink. Saved the lot of them.

Rick Feineis
Managing Partner
Manta Ventures, LLC
http://www.sea-pack.com

That's nice- does it work without the syrup? I'm asking because you didn't really answer Farmer's question, and in all honesty, it would be my first one. My second question would be is their a field expedient alternative to the proprietary goo?

http://www.straightdope.com/mailbag/msaltwater.html

http://www.seashellsandsuch.com/articles/canidrinkseawater.php

I'm not sure what the resource is on drinking a liter a day, but that would appear to make your body use more than a liter to dispose of the wastes in seawater. It may be that the liter a day presumes fresh water is freely available? Drinking only seawater at even a liter a day would appear from other online resources to mean you would deplete your stores of body fluids more quickly than not drinking at all.

The FAQ says the basic filtration speed at 95 degrees Fahrenheit is 0.5 liters in 3.6 hours. That's about how long it takes me to drink 2 to 3 liters at Burning Man at that temperature. Of course, I'm active during the day. I guess if I'm on a liferaft at see, I won't be going anywhere. :-> Still, I'm not sure I'd be happy with a half liter every 3 to 4 hours, assuming the water is 95 degrees.

I'm unable to determine what the specs mean for the Seapack:
"Volume: 1.8 liters"
Does this mean the bag will let me put in 1.8 liters, then filters it at the rate of a half liter every 3.6 hours at 95 degrees? And it comes with 5 syrup bags that produce 2.5 liters of 'survival drink"? One bag per half liter, it seems.

I note that a serving size of the drink is 8 fl. oz. :->

Their catalog says that the syrup is required to drive the osmosis process. I'm sure this particular bottle of this particular syrup is not required, but you'd have to find the right chemistry if you wanted to do it yourself.