A bidirectional electrostatic microvalve with microsecond switching performance

This paper describes a new bidirectional high-pressure gas electrostatic microvalve that opens and closes in 50 its or less. The microvalve consists of a valve-closing electrode, a flexible movable membrane, and a valve-opening electrode that is directly opposed to the valve-closing electrode. The membrane contains an embedded electrode, so the valve can zip closed when a potential is applied between the membrane and the valve-closing electrode. The valve-opening electrode allows the valve to open again in a rapid discontinuous motion, without requiring a large applied potential. A pressure-balance port is used to enhance the microvalve switching speed and to allow the valve to close against applied pressures greater than 8.3 atm (840 kPa). The gas conductance through the valve is 2.8 nt/Pa . s (17 sccm/atm), and the fluid leakage measured zero over the entire pressure range up to a burst pressure of 10.8 atm (1.1 MPa). Measurements show that the valve can open or close in 50 mu s or less for applied pressures tip to 126 kPa. In an extended lifetime test, a sample microvalve has been opened and closed 47 million times before failure.