A PZT-driven micropump

The design, fabrication and characterization of a PZT-driven micropump is presented in this paper. It consists of a chamber, a membrane, two microvalves and a driving mechanism. The thickness of the micropump membrane is 11 /spl mu/m. The micropump chamber is round with diameter of 5 mm and depth of 0.4 mm. The microvalves made of single crystallite silicon are used on this micropump as flow direction control elements. The dimension of the valve cover is 1.5 mm/spl times/1.0 mm/spl times/7.4 /spl mu/m and dimension of the valve opening is 200 /spl mu/m/spl times/200 /spl mu/m. Its capability of flow is more than 10 ml/min at a pressure level of about 10 kPa. The open pressure in the obverse direction is less than 200 Pa while the leakage of reverse direction is almost zero. The features of the microvalve fit the requirement of the micropump well. When the micropump chamber chip and two valve chips are assembled together as a micropump, this micropump is mounted on a metal base and then the PZT bimorph cantilever is mounted above the micropump membrane. The maximum flow rate of the micropump is 365 /spl mu/l/min under 100 V, 20 Hz square wave power supply and zero pressure fall. The back pressure is 2.38 kPa and the flow control precision is better than 1 /spl mu/l.