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Conductance valve and pressure-to-conductance transducer method and apparatus

United States Patent

January 18, 2005
View the Complete Patent at the US Patent & Trademark Office
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A device for interrupting or throttling undesired ionic transport through a fluid network is disclosed. The device acts as a fluid valve by reversibly generating a fixed "bubble" in the conducting solvent solution carried by the network. The device comprises a porous hydrophobic structure filling a portion of a connecting channel within the network and optionally incorporates flow restrictor elements at either end of the porous structure that function as pressure isolation barriers, and a fluid reservoir connected to the region of the channel containing the porous structure. Also included is a pressure pump connected to the fluid reservoir. The device operates by causing the pump to vary the hydraulic pressure to a quantity of solvent solution held within the reservoir and porous structure. At high pressures, most or all of the pores of the structure are filled with conducting liquid so the ionic conductance is high. At lower pressures, only a fraction of the pores are filled with liquid, so ionic conductivity is lower. Below a threshold pressure, the porous structure contains only vapor, so there is no liquid conduction path. The device therefore effectively throttles ionic transport through the porous structure and acts as a "conductance valve" or "pressure-to-conductance" transducer within the network.
Schoeniger; Joseph S. (Oakland, CA), Cummings; Eric B. (Livermore, CA), Brennan; James S. (Rodeo, CA)
Sandia National Laboratories (Livermore, CA)
10/ 304,346
November 25, 2002
STATEMENT OF GOVERNMENT INTEREST This invention was made with Government support under government contract no. DE-AC04-94AL85000 awarded by the U.S. Department of Energy to Sandia Corporation. The Government has certain rights in the invention, Including a paid-up license and the right, in limited circumstances, to require the owner of any patent issuing in this invention to license others on reasonable terms.