Working principle and performance of the dynamic micropump

Dynamic micropumps employing pyramid-trunc shaped diffusers as dynamic passive valves have been developed, built and tested. They are particularly characterized by a very simple fabrication technology and good high frequency performance. A prototype being 5*5*lmm³ in size reached with methanol a zero load pump rate of more than 300 μl/min and a maximum pump pressure of about 7 kPa at 5 kHz working frequency. Dynamic micropumps can, therefore, compete with known solutions of similar or even bigger size. The direction-dependent behaviour of silicon microdiffusers have been experimentally investigated; the results are discussed. Based on the found characteristics, a static model for dynamic membrane pumps has been derived. The calculated parameters match quite well the real values of different tested micropumps. By the static model, pump layout adapted to the demanded application becomes easier