Claims
- 1. A water sensor/actuator comprising:
a water permeable housing; a plug of dry and compressed fibrous cellulosic material having a powder material thereon and mixed therewith, said plug being compressed along an axis thereof and fitted in a portion of said housing adjacent one end thereof; said cellulosic material having anisotropic moisture-absorbing properties wherein dried-in strain of said cellulosic material is greatest along said axis; 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; and a piston fitted in said housing adjacent said plug, wherein immersion of said housing in water causes expansion of said plug and corresponding movement of said piston.
- 2. A water sensor/actuator as in claim 1 wherein said cellulosic material is derived from a plant.
- 3. A water sensor/actuator as in claim 1 wherein said cellulosic material is cotton cellulose.
- 4. A water sensor/actuator as in claim 1 wherein said powder material is selected from the group consisting of: a mixture of sodium bicarbonate and citric acid; and a mixture of sodium bicarbonate and potassium hydrogen tartrate.
- 5. A water sensor/actuator as in claim 1 further comprising means for retaining said piston adjacent said plug before and during said expansion thereof.
- 6. A water sensor/actuator as in claim 5 wherein said means comprises a spring fitted in said housing.
- 7. A water sensor/actuator as in claim 1 wherein said powder material is selected such that another product of said chemical reaction is gaseous.
- 8. A water sensor/actuator comprising:
a water permeable housing; a plug of dry and compressed fibrous cellulosic material having a powder material thereon and mixed therewith, said plug being compressed along an axis thereof and fitted in a portion of said housing adjacent one end thereof; said cellulosic material defined by a Cellulose II form having fibrous cellulose tubes substantially aligned with said axis; 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; and a piston fitted in said housing adjacent said plug, wherein immersion of said housing in water causes expansion of said plug and corresponding movement of said piston.
- 9. A water sensor/actuator as in claim 8 wherein said cellulosic material is derived from a plant.
- 10. A water sensor/actuator as in claim 8 wherein said cellulosic material is cotton cellulose.
- 11. A water sensor/actuator as in claim 8 wherein said powder material is selected from the group consisting of: a mixture of sodium bicarbonate and citric acid; and a mixture of sodium bicarbonate and potassium hydrogen tartrate.
- 12. A water sensor/actuator as in claim 8 further comprising means for retaining said piston adjacent said plug before and during said expansion thereof.
- 13. A water sensor/actuator as in claim 12 wherein said means comprises a spring fitted in said housing.
- 14. A water sensor/actuator as in claim 8 wherein said powder material is selected such that another product of said chemical reaction is gaseous.
CROSS-REFERENCE TO RELATED PATENT APPLICATIONS
[0001] This patent application is co-pending with two related patent applications entitled “SAFETY AND ARMING DEVICE USING CELLULOSE-BASED SENSOR/ACTUATOR” (Navy Case No. 82769) and “MOISTURE-ABSORBING CELLULOSE-BASED MATERIAL” (Navy Case No. 82772), filed on the same date by the same inventors as this patent application.
ORIGIN OF THE INVENTION
[0002] The invention described herein was made in the performance of official duties by employees of the Department of the Navy and may be manufactured, used, licensed by or for the Government for any governmental purpose without payment of any royalties thereon.