New bi-directional valve-less silicon micro pump controlled by driving waveform

A new bi-directional valve-less silicon micro pump was proposed based on the analysis using an equivalent circuit model, and a performance of the fabricated pump was studied. The flow direction of the pump can be controlled by changing a driving waveform applied to a PZT plate fixed on a diaphragm. The feasibility of this new bidirectional pumping principle was verified by the experiments. The pump generated maximum flow rates of 220 nl/s for forward direction and 190 nl/s for backward direction and maximum pumping pressures of 9.7 kPa for forward direction and 8.3 kPa. for backward direction.