平面被動閥式微幫浦之最佳化設計

Abstract

平面被動閥式微幫浦之制動原理為利用壓電薄膜驅動緩衝腔體後，產生之往復流場來推動閥門動件進行開關的動作。相較於無閥門微幫浦之特性，由於採用被動閥門元件，能提供良好之導流效率(71%)。 根據實驗結果，減少閥門動件質量對於降低微幫浦在幫浦模式以及補充模式間的切換時間有其f顯著效果，並能提供更有效的導流效率。採用質量為13.6μg的閥門動件之微幫浦Type1，在工作條件為30V及800 Hz下能提供266μl/min的流量，而當微幫浦採用質量減輕為10.6μg以及6.8μg之閥門動件時，微幫浦Type2及Type3之體積流率分別提升至290μl/min與360μl/min，結果顯示微幫浦的效能與閥門動件質量有關。 研究採用微粒子顯像測速儀(Micro-Particle-Image-Velocimetry)來觀測閥門動件的暫態運動以及下游閥門之導流效率。根據實驗結果，閥門動件在幫浦模式以及補充模式間的切換時間，會隨著閥門動件質量的降低而減少，因此導流效率也隨之增加。本研究開發之微幫浦可滿足微流系統的性能需求，並利於微型全分析系統(Micro-Total-Analysis-System,簡稱Micro-TAS)以及實驗室晶片(Lab on a chip)之整合與應用。

The novel PZT micropumps with planar passive valves were successfully developed in this study. The periodically moving planar passive valves were actuated by the oscillatory flow which is due to the oscillation of a PZT membrane. The present micropump with planar passive valves provided higher diodicity (71%) with respect to previous valveless micropumps. From experimental results, reducing the mass of planar passive valves is useful to block the backward flow rapidly and decrease the switch time between pump mode and supply mode. In Type 1 device with planar passive valves of 13.6 μg, the optimum volume flow rate 266 μl/min was obtained at excitation voltage of 30 V and working frequency of 800 Hz. As the mass of passive valves were reduced to 10.6μg and 6.8 μg, the volume flow rates increased to 290 μl/min and 360μl/min, respectively. The results reveal that the performance of micropump was dominated by the mass of the moving parts. The transient motions of planar passive valves were observed by Micro-Particle-Image-Velocimetry (μ-PIV) and then the flow-rectified capabilities of the present device were analyzed. From the experimental results, the switching time decreased as the mass of moving part reduced, and thus the higher diodicty was obtained. This study indicates that this device fulfills the demands for microfluidic systems. Moreover, the present device can be applied to μ-TAS or lab-on-a-chip in the future.