A planar cascading architecture for a ceramic Knudsen micropump

This paper describes a 9-stage Knudsen pump with planar architecture that uses nanoporous ceramic for thermal transpiration. While operating at 55 K above room temperature, the pump provides a maximum pressure head exceeding 12 kPa at a sealed outlet, or a gas flow rate of ap3.8 muL/min. against a pressure head of 160 Pa. Experiments also demonstrate the capability of the pump to steer water droplets at speeds exceeding 1200 mum/s through a 250 mum fluorinated ethylene propylene capillary. The packaged volume for the 9-stage pump discussed here is 25times25times7.25 mm³. These characteristics indicate that the pump is potentially useful in microfluidic systems intended for both gas and liquid phase chemical sensing.