Actuator with osmotic pressure actuation

Claim 1

In combination: a sensor for detecting and responding to the presence of a suitably concentrated liquid solution with a pre-selected concentation of a solute comprising: a rigid case having an internal wall forming a rigid internal chamber to contain liquid of lesser or no concentration of said solute and through the said wall an exit port entering said chamber: a closure incorporating a membrane possessing osmotic properties closing said exit port, said membrane occluding at least part of said exit port, whereby liquid leaving said chamber must pass through the membrane; and actuator means responsive to a lowered pressure caused by exit of liquid from the chamber because said membrane contacts a liquid of at least said pre-selected concentration of solute to result in osmotic flow tending to dilute the last named liquid, said actuator means comrpising: an axially movable plunger slidingly fitted in an aperture in the wall of the case, entering in and exposed to pressure in said chamber, and exposed externally to a different pressure: and a separation mechanism responsive to the position of said plunger.