A digital miniature pump for medical applications

This paper describes the principle, design, control and performance of a novel miniature linear peristaltic pump. Exhibiting dual and bi-directional feed capabilities that allow the simultaneous pumping of two distinct fluids at measured and precise flow rate, the pump consists of two resilient tubes and two directly actuated pumping units. Both of the two flexible tubes are placed in the pumping units in such a way that when a pumping element reciprocates in any direction to collapse one adjacent segment of the tubing, it will release the other adjacent segment of the same tubing at the same time. The two pumping elements reciprocate in a sequence so that fluid in the flexible tubing is continuously pumped in preset direction. For each pumping element, two reflective optical sensors are used to detect its position. Based on the output of the four position sensors, a digital logical control circuit is built for the pump. Experimental results show that this kind of miniature pump has potential applications in portable infusion/suction systems.