基于MEMS技术的三明治结构被动阀微泵研制

Development of Sandwich Structure Micropump with Check Microvalve Based on MEMS Technology

为解决微泵自吸困难、难以实现流速精确控制等问题,利用MEMS技术研制出具有三明治结构和两被动阀的压电驱动微泵,其中泵腔、泵膜和阀片分别由硅、聚二甲基硅氧烷(PDMS)和SU-8构成.从理论上,分别对气体和液体微泵的工作原理、被动阀性能以及结构参数对微泵工作性能的影响进行了分析.综合两类微泵特点,提出了气液两用微泵设计方案、工艺流程及其优化方案.在不同驱动电压条件下测试了具有不同形状泵腔、不同阀口尺寸和不同类型阀片结构的微泵.实验结果表明,该微泵可用于气体和液体介质,气、液体的最大流量分别达到53.6mL/min和1 280μL/min;泵腔高度影响到微泵的体积压缩比,是影响微泵自吸的一个重要因素.该泵具有结构简单、自吸、低成本、易于加工及操作方便的特点.

To solve self-priming and difficulty in precisely controlling flow rate , the piezoelectric driving micropump with a sandwich structure and two check valves was fabricated by using MEMS technology. The micro-chamber, micropump membrane and valves were made from silicon, polydimethylsiloxane （PDMS） and SU-8, respectively. The working principle of gas and liquid micropumps, the performance of two different passive check valves, and the effect of structural parameters on the performance of mi- cropump were theoretically discussed in detail. Based on the comprehensive characteristics of the two kinds of micropumps, the design protocol, fabrication process and optimization of gas and liquid mi- cropumps were presented. Micropumps with different micropump chambers, different sizes of valve port, different microvalve structures were tested under different driving voltages. Experimental results illustrate that the micropump can be used to pump gas and liquid, and that the maximal flow rates of the gas and liquid micropumps reach 53.6 mL/min and 1 280 p,L/min, respectively. The compression ratio of vol- ume, which is affected by the height of micropump chamber, is an important factor for self-priming. The micropump is characterized experimentally by the merits of simple structure, self-priming, low cost, easy fabrication and easy operation.