A Universal Piezoelectric Micropump With Capabilities of Self-Cleaning, Stable Filtration and Precise Pumping

The microliquid supply system based on piezoelectric micropump has been deeply studied. However, it is difficult to realize stable and efficient filtration in quantitative liquid supply due to the blockage of filter membrane. In this article, we propose a self-cleaning filtration and pumping system based on piezoelectric micropump, which can realize stable and long-term directional quantitative filtration and pumping at the same time. The self-cleaning of the filter membrane is realized by using its reflux characteristics and the blockage problem of the current microfiltration system is solved. The key structure size of the system is optimized to realize continuous self-cleaning of filter membrane and high efficiency transportation of micro fluid. The control methods of pumping and filtration performance are proposed. Experiments results shows that the transmembrane pressure tends to be stable after about four pulse voltages which proves that the continuous self-cleaning is achieved. The reflux rate can be reduced to 25%, and the minimum pumping volume control accuracy is about 40 nL per cycle. This article can be used as a reference for microanalysis systems that need stable filtration and on-demand liquid supply.