Design of a Simple Valveless Micropump Using Piezoelectric Actuators

An open valveless micropump pumped by a disk-shaped piezo-electric actuator was developed, and its working principles were investigated. The electrode of the pump buzzer was divided into two semicircles as piezo-electric actuators, and single-phase or dual-phase AC driving potential was applied. The flowrate of the pump was analyzed when actuated in basic symmetric (W00) and antisymmetric (W01) modes. The finite element package software ANSYS was used to analyze the resonant frequency and mode of the buzzer under fluid loading, and the vibration displacement generated by the single-phase and dual-phase time-harmonic actuation was both simulated by using an additional mass method and experimentally investigated. The experimental results show that the resonant frequency of the disk-shaped actuator decreased due to the fluid loading effect and as the gap distance between the conduit and the actuator decreased. The maximum flow rates of the W00 and W01 mode actuated pumps were 133.13 and 9.63 mL/min, respectively. The driving frequency with the highest pump efficiency was slightly lower than the resonance frequency of the fluid-loaded buzzer. Applying a hydrophobic treatment to the back of the buzzer decreased the resonance frequency under fluid loading. The results show that simulating the structural resonance frequency for various fluid loads by the additional mass method is feasible. The flow direction could be controlled by activating the W01 mode.