Environmental Sensors and Subsystems

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A Scalable, Modular, Multi-Stage, Peristaltic, Electrostatic Gas Micro-Pump
Ali Besharatian, Karthik Kumar, Rebecca L. Peterson, Luis P. Bernal, and Khalil Najafi
Conceptual illustration of the smallest pumping unit, consisting of two stages, showing the detailed layout of each chamber and fluidic paths (left), and photo of a fabricated 24-stage device after packaging, on a U.S. penny (right).
Conceptual illustration of the smallest pumping unit, consisting of two stages, showing the detailed layout of each chamber and fluidic paths (left), and photo of a fabricated 24-stage device after packaging, on a U.S. penny (right).

Gas micropumps are needed in many emerging applications, including gas chromatography, resonant/IR sensors, atomic clocks, and mass spectrometers. High pressure and flow are important requirements, which in turn require large-stroke and/or high-frequency actuators with low power consumption and small size. Previous gas micropumps exhibit limited capabilities due to use of bulky actuators, often were slow or power/size inefficient, and lacked scaling/integration capabilities. Our group introduced the first electrostatic peristaltic gas micropump, which utilized fluidic resonance and a multi-stage configuration to achieve the highest recorded flow and pressure in a low-power and small-volume system. However, it had inherent limitations in scalability, sealing and yield due to challenging alignment and bonding.

This project seeks to develop a MEMS pump that can be used as the roughing pump in a three-part micro-scale vacuum system. The new pump utilizes the same operating principle as previously reported, but with major modifications in device architecture, totally new fabrication technology and modular assembly/packaging. The modular fabrication technology has a final process yield of 90% with a high throughput and high control over critical design parameters (<5% error). Moreover, the device total size is 60% smaller than the old design, due to the use of a novel honeycomb planar architecture. Under preliminary testing, the microfabricated 24-stage pump successfully produced a flow rate of 0.36 sccm and a pressure accumulation of ~500 Pa at 22 kHz. This work is supported by the DARPA CSVMP program under grant #W31P4Q-09-1-0011.

Updated 03/30/2012