Study Of Valveless Piezoelectric Micropump Based On MEMS Technology

Micropump as the core component of microfluidic system has become the research focus in Microfluidic Systems field.In order to realize the miniaturization and integration of the microfluidic chips,it is urgent to investigate a miniature valveless piezoelectric micropump which can transport the micro fluid continuously.Traditional pump can not satisfy the requirements account for its volume or limitation of Working Mechanism.As the MEMS technique developing,there is a rapidly growth on achievement of the pump micromation by utilizing MEMS technology.As a result,the researches were concentrated on developing a small size and simple structure micropump to transport the micro fluid by using MEMS technology.Based on the analysis in the structure and principle of the micropump,a valveless piezoelectric micropump in parallel with double chambers is designed and manufactured. This micropump uses the bimorph as the actuator which has the more driving force;using a diffuser and a nozzle unit which is easy to fabricate;utilizing poly-dimethylsiloxane(PDMS) as diaphragm which is not easy to destroy and has a low manufacture cost;using structure with double chambers which are in parallel,the structure decreases the pulsatile flow and improves the efficiency.The driving performance of the piezoelectric bimorph is simulated by Finite Element Analysis(FEA)software ANSYS;the pump body and pump diaphragm are manufactured by MEMS technology and are glued to the bimorph,which compose the micropump;the max free end displacement of the bimorph is measured by measurement system in the different voltage and frequency;the measurement system is built,which measures the flow rates of the micropump in different condition,the result is compared with that of the micropump with the single chamber.The result shows that the thickness of membrane,frequency and voltage all have an influence to the flow rate,when the backpressure is 0,a sine wave of 80V and 1100Hz is applied,the thickness of diaphragm is 73μm,the length of bimorph is 30mm,the maximum flow rate of the valveless piezoelectric micropump in parallel with double chambers reaches to 210μL/min,which is one and a half times as the micropump with the same single-chamber structure.