Normally close microvalve and micropump fabricated on a silicon wafer

A normally closed microvalve and micropump were fabricated on a silicon wafer by micromachining techniques. Normally closed microvalve has a silicon diaphragm and a small piezoelectric actuator to drive it. The controllable gas flow rate is from 0.1 ml/min to 85 ml/min at a gas pressure of 0.75 kgf/cm/sup 2/. The micropump is a diaphragm-type pump which consists of two polysilicon one-way valves and a diaphragm driven by a small piezoelectric actuator. The maximum pumping flow rate and pressure are 20 mu l/min and 780 mmH/sub 2/O/cm/sup 2/, respectively.<
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