| Summary: | 碩士 === 國立臺灣海洋大學 === 機械與機電工程學系 === 101 === A pneumatic micropump usually uses a membrane as an actuating element and two flap-type check valves to resist reverse flow. High-pressure air is applied to make membrane produce periodic deflection, driving fluid forward. Flap-type microvalve has disadvantages such as low forward flow rate due to its high fluidic resistance, and reverse flow leakage due to incomplete sealing between the flap and channel walls. A membrane-type microvalve was proposed by our laboratory member, Chih-An Dai. It has a feature that a membrane with holes around its edge sits between two vertical channels with different diameters. It has the advantage that forward flow is easy to cross membrane holes from small channel to large channel; however, reverse flow is efficiently blocked as the small channel is completely covered by the membrane .
To enhance the performance of micropump, this study is to design a new micropump with a membrane and two membrane-type microvalves. The usual pump with flap-type membrane is used as a baseline design. The micropumps are made of polydimethylsiloxane and fabricated by soft lithography technique.
Studies shows that the maximum flow rate of our micropump is 48.1 L/min under 60 kPa working pressure and 2 Hz working frequency, enduring maximum back pressure of 17 kPa; maximum flow rate of the baseline micropump is 23.5 L/min under the same condition, enduring maximum back pressure of 13 kPa. According to the studies, the the maximum flow rate of our micropump is 2.05 times of the baseline micropump. This outperformance can attribute to a good reverse/forward fluidic resistance ratio. The ratio of our pump is 2.22 times of the baseline micropump, which is close to the ratio of maximum flow rates.
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