Casio unveils electroosmotic pump for RMFC J apan's Casio Computer Co has devel- oped an electro-osmotic (EO) pump that is optimized for use in reformed methanol fuel cell (RMFC) systems designed to power mobile devices. A working demonstration of the firm's System Version 35, incorporating the micro-pump, was displayed at the Fuel Cell Seminar in Honolulu last fall.
The fuel-supply micro-pump is made from an EO material -a dielectric medium such as silica, which produces an electrical potential when it comes into contact with a liquid. Conversely, applying a voltage to the outside of the unit causes the liquid inside to move, since when a voltage is applied to electrodes made of a microporous electro-osmotic material, the surplus cations in the liquid migrate to the negative pole. The viscosity of the liquid itself causes the liquid to flow in the direction of the cations, creating a pump function.
Despite its compact size, the pump can dispense liquid at high pressure, and since it has no motor, it operates quietly and does not introduce problems such as pulsation. The pump is able to dispense precise quantities of methanol while maintaining a high pressure, in a compact (0.5 cm 3 ) unit. It is made from materials developed by Nano Fusion Technologies Inc.
Casio says that it has resolved problems inherent in EO pump technology, such as the EO material's susceptibility to impact damage, or the build-up of vapor bubbles caused by liquid electrolysis. In doing so it has created a high-performance, compact pump that can maintain a flow rate of 90 ยตl/min even at 100 kPa.
The firm aims to start delivering samples of the system for performance evaluation in fiscal 2008.
For more information, go to: world.casio.com