Series and parallel integration of flow regulators for precise and multiple-output fluid delivery

Abstract

The passive flow regulator for accurate flow control is vital in miniaturized microfluidic systems. The reported regulators commonly have complex structures and fabrication processes, and could only deliver fixed flow rates. In this paper, the series and parallel integrations of single membrane flow regulators were reported to achieve the enhanced flow control and the multiple-output fluid delivery. To understand the flow adjustment characteristics, a series of prototype devices with different structural dimensions were systematically investigated. Our flow regulators were fabricated in low-cost polymer films using a quick nonclean room fabrication process. By adjusting the structural parameters, our flow regulators were able to output the stable flow rates of 100–2000 µL/min over a wide pressure range of 1000–4000 mbar. More importantly, the strategies of series and parallel integrations of single passive flow regulators were carried out to create the precise and multiple-output fluid delivery. The series-connected flow regulators could reduce the fluctuation of flow rates to be less than 1.5% under highly varied pressures. Through selectively turning off the branches, the parallel-arranged flow regulators could output various precise flow rates as demanded. Therefore, we envisioned that our integrated flow regulators held the potentials for controlling fluid with on-demand flow rates in portable microfluidic systems.