Microachined bi-directional liquid pump with thermally controlled dynamic valves

摘要

A micropump based on a novel flow rectification principle is developed. The proposed pump consists of a chamber with a diaphragm actuated by a piezoelectric element, and a pair of "dynamic valves," the function of which can be controlled thermally without mechanically movable parts. The mechanism of flow rectification is based on the strong temperature dependence of hte liqudi viscosity. This principle is verified with a prototype device fabricated by silicon based micro technology. Through the experiments it is shown that the flow rate is proportional to the duration and the power of the heating pulse. The highest measured flow rate in the case of water is 5.5 mul/min. The ability of bi-directional pumping is also confirmed.