Cryogenic cooling systems play increasingly important roles in both military and commercial applications. These systems are essential for the operation of superconducting electronics and sensors. The development of innovative cryogenic cooling solutions to replace the traditionally bulky, complicated, and less efficient devices that rely solely on heat conduction is becoming more and more attractive. Spot cooling is a novel concept for cryogenic cooling systems. However, spot cooling devices require a compact, efficient and reliable pump that can pump cryogenic fluids. This paper presents preliminary efforts on developing a micro pumps for cryogenic cooling of certain specialty electronics, including those of sensor and detector applications. A packaging method compatible with cryogenic applications is proposed. The tested micro pump, fabricated by MEMS techniques, had a saw-tooth emitter and planar collector with 50-μm electrode spacing and 200-μm pair spacing. The pump was tested in sub cooled liquid nitrogen (with about 7 K sub cooling). It was shown by the experimental tests that liquid nitrogen is pumped by the EHD effects if the electrodes of the pumps are properly designed. The tested micro pump pumped liquid nitrogen at a flow rate of 2.3 g/min and had an output pumping head of 5 Pa when 1000 volts were applied across the electrodes.

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