Development of a new type of micro fluidic system using EO pumps

This paper presents a novel micro fluidic system based on two EO (electroosmotic) pumps. This system consists of two EO pumps, one indirect pumping mechanism, and two switching valves. The indirect pumping mechanism includes two sealed chambers, one is the driving fluid chamber and the other is working fluid chamber. The EO pumps actuator make the diaphragm which separates two chambers reciprocate. So the liquid in the working fluid chamber can be pumped from inlet to outlet. Due to the large deflections of the actuator membrane, the device is completely self-filling and able to pump liquid. By using the indirect pumping mechanism, the problem of driving fluid circulation has been improved. The operation of the micropump was investigated experimentally. And a maximum flow rate of 194 μl/min (using water) back-pressure 119 kp was obtained by an input voltage of 20 V and an exciting frequency of 1.6 Hz. A close loop control system was designed to obtain stable flow rate. In this paper, the flow rate was controlled at 125 μl/min and an experiment was accomplished to show the performance of the system. These experiments results demonstrate the fluidic system performance and ability to deliver the fluid and drags to LOC (laboratory-on-a-chip) for chemical analysis.