分離式圓形雙簧壓電薄膜泵之設計與性能研究

Abstract

本研究提出可應用於微型輸液之分離式壓電泵浦，整體微型泵採用組合式設計，選用漸擴管作為流向控制元件，並採用輸出力量較大之雙簧圓形壓電片為致動器，藉由傳力柱與薄膜傳遞動能給流體。組裝時，塗佈一層黏膠以確保氣密性與薄膜平整度，提升幫浦之流量穩定性，以進行各參數影響評估。實驗設計參數包含:壓電片基板厚度、薄膜材質與厚度、傳力柱與腔體直徑大小，同時以理論分析各元件對於流量的影響，最後選擇最佳化之泵浦進行效能測試，觀察此分離式微型泵的流量穩定性、揚程及效率表現。 研究結果顯示，在薄膜選擇上，楊氏模數較大之非彈性體，其流量表現較彈性體材料為佳；而較薄之壓電片基板其變形曲率較大，故流量較大，並以0.2mm厚的黃銅基板為最佳；此外，在固定柱腔比(傳力柱與腔體直徑比值)下，腔體直徑由26mm 縮小至15mm 能使流量從1675μl/min提升至2686μl/min;另一方面，因壓電片在不同條件下之變形量具顯著差異，故在定義腔體大小與最佳柱腔比之關係時，需同時評估每次壓縮體積與等效彈性係數之影響。最後，本研究之最佳化分離式無閥微型泵可提供最大流量為7549μl/min，揚程為1.5kPa，誤差控制於±5%。

In this study, a separable piezoelectric micro-pump which can be applied in medical and chemical infusion was presented. The structure includes nozzle/diffuser for valveless design, the plunger and a diaphragm for delivering the kinetic energy to fluid, and a circular bimorph piezo disk for offering sufficient force. Also, in purpose to easily test the influence of parameters, the separable pump was formed through assembly. Further, glue spreading can assure airtight character and diaphragm smoothness. Five parameters such as working frequency, diaphragm properties, the thickness of the passive plate in the actuator, ratio of plunger diameter to chamber diameter(Piston ratio, P), and chamber diameter are analyzed to evaluate the performance of the micro-pump. Eventually, the optimal micro-pump has been tested about its flow rate stability and pumping head. The experimental results indicate that plastic material is more appropriate than elastomer for separable pump, the thinner passive plate can perform bigger deflection, and different chamber diameter should combine with different Piston ratio to create more flow-rate. As a result, the optimal combination for the separable pump was achieved with 0.2mm thickness of the passive plate, 0.1 mm thickness PET diaphragm, 0.67 Piston ratio, 15mm chamber diameter, and working frequency in 45Hz. Maximum flow-rate can reach 7.5 ml/min while the maximum pumping head is 1.5kPa, also, the relative errors can be controlled in 5%.