Patent ID: 7368056

Claim:
A device for producing potable liquid, said device comprising a water-absorbing solute encapsulated by a non-porous, water-permeable polymer membrane, wherein said polymer includes hydrophilic segments or blocks and comprises a member selected from the group consisting of polyurethane elastomers, crosslinked silicone elastomers, thermoplastic silicone-containing copolymers, polyolefin elastomers, styrene-diene copolymers, polyester-polyether copolymers, and polyamide-polyether copolymers, wherein said polymer membrane has a moisture vapor transmission rate by ASTM Method E96BW greater than 100 g/square meter/day at 1 mil thickness, a dry tensile strength of greater than 500 psi, and a permeability to said solute of less than 10 −3 cm 2 /sec, and wherein said water-absorbing solute is capable of providing said device with a pressure of approximately 0.1 psi or more for a period of at least 24 hours.