Development of large flow rate, robust, passive micro check valves for compact piezoelectrically actuated pumps

A robust passive high frequency high pressure micro check valve was developed for piezoelectrically actuated pumps. A novel cross-patterned microvalve flap is used to increase the valve's structural stiffness with pressures up to 10 MPa. A mechanical valve stopper prevents valve-flap failure under extreme high pressure. The valve-flap is also designed to work at frequency larger than 10,000 Hz. The valve-flap was fabricated with electroformed nickel on silicon substrate. Deep RIE etching was used to fabricate the valve channels in the silicon substrate. The whole valve weighs 0.2 g including packaging. The microvalve flow rate (water) is measured to be 18 cm3/s under a pressure difference of 50 psi. The microvalve was integrated with a compact piezoelectric pump and produced pressure of 350 psi when operated at 10 kHz frequency.