An Integrated Electrostatic Peristaltic 18-Stage Gas Micropump With Active Microvalves

We report the development of fully integrated peristaltic multistage (18-, 4-, and 2-stage) electrostatic gas micropumps with integrated active microvalves. These micropumps uniquely combine a number of approaches to achieve highpressure, high flow rate, multimode, and low-power pumping of compressible gases: (1) multistage (up to 18-stage) configuration to generate high pressure accumulation across the pump, while allowing each stage to operate at low pressure burden; (2) gas resonance-based high-frequency (>10 kHz) operation of both the micropumps and the microvalves to achieve high mass flow rates despite the small volume displacement of microscale membranes; (3) active timing control of microvalves to regulate compressible gas pumping into multiple modes for either high flow rate or high pressure; and (4) electrostatic actuation to minimize power consumption despite multiple (up to 28) membrane operation. The multistage micropumps contain 18, 4, and 2 pumps connected in series sandwiched by 19, 5, and 3 microvalves, respectively. The fabricated 18-, 4-, and 2-stage pumps, respectively, produced high air flow rates of ~4.0, 3.0, and 2.7 sccm and maximum pressure differentials of ~17.5, 7.0, and 2.5 kPa with total power consumptions of only ~57, 15.1 and 9.1 mW, respectively. They have active areas of 15.5 × 12.7 and 18.3 × 7.1, 15.0 × 7.0 mm², and total package volumes of 25.1 × 19.1 × 1, 27.8 × 11.6 × 1, and 23.0 × 12.4 × 1 mm³, respectively. They demonstrated two pumping modes using different microvalve timing (high flow rate timing and high pressure timing), resulting in notable changes in flow rates and pressure generation. One 4-stage micropump has been actuated for a total running time of more than 700 min over 32 months.