Patent ID: 6561023
Filing Date: 2003-05-13
Classification: G01N

Abstract:
A water sensing actuator comprising:a water permeable housing; a fibrous cellulosic material having fibers extending therealong, said cellulosic material having a dried-in strain that is greatest along an axis of said cellulosic material; a powder material adhered to and residing between said fibers, said powder material being inert with respect to said cellulosic material and initiating a chemical reaction when exposed to water, wherein a product of said chemical reaction is water; said cellulosic material, with said powder material adhered to and residing between said fibers thereof, being compressed along said axis of said cellulosic material to form a plug having an axis of compression that is aligned with said axis of said cellulosic material, said plug being fitted in a portion of said housing adjacent one end thereof; and a piston fitted in said housing adjacent said plug and approximately perpendicular to said axis of compression, wherein immersion of said housing in water causes expansion of said plug along said axis of compression and corresponding movement of said piston.