Osmotically driven fluid dispenser

Claim 1

An osmotically driven fluid dispenser for use in a surrounding aqueous environment consisting essentially of: a. a single shape retaining closed canister that defines the exterior of the dispenser which exterior is exposed completely to the aqueous environment, at least a part of the wall of the canister being made of a material of controlled permeability to water; b. an osmotically effective solute confined within the canister which, in aqueous solution, exhibits an osmotic pressure gradient across said portion of the canister wall against the water of said environment, said canister being substantially impermeable to the solute; c. an outlet in the canister wall; and d. a flexible bag adapted to hold the fluid to be dispensed and housed within the canister with its open end in sealed contact with a portion of the canister wall such that the outlet communicates with its interior and its interior is closed to the solute and aqueous solution thereof with the remainder of the bag being spaced from the remaining portion of the canister wall and generally unsupported thereby, the exterior of said remainder being exposed to the solute and aqueous solution thereof, whereby water is imbibed into the canister from the environment through said part of the canister wall by the solute and the imbibed water exerts hydraulic pressure uniformly on the exterior of the flexible bag exposed thereto, causing the bag to collapse inwardly thus squeezing the fluid out of the bag via the outlet.