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Modular stacked variable-compression ratio multi-stage gas micropump

We report the design, fabrication and testing of a new “stacked” multi-stage electrostatic gas micropump. Utilizing a stacked structure provides modularity as well as the ability to change the number of pumping stages post-fabrication to achieve the required pressure for a given application. The stacked design also eliminates the need for bidirectional movement of the pumping membrane. The new design presents a novel method to adjust the volume ratio of a given stage to achieve a uniform pressure increase across individual stages of the multi-stage system. A pressure difference of 1.1kPa and air flow rate of 85 μL/min is obtained by a 3-stage stacked micropump. An individual micropump stage is 5.5×4×0.5 mm3 and each pumping/microvalve membrane is 2 × 2 mm2.