Standing Air Bubble-based Flow Regulation System

The syringe pump is widely used in microfluidic systems as a liquid sample handling method. However, the step motors in syringe pumps often produce undamped pulses, resulting in the unstable fluid delivery in micro-channel. In this paper, a novel active flow regulation system has been proposed, which functions as a micro damper. A bubble-based micro-damper consists of three parts: a liquid channel, a gas channel as a control section beside it, and specially designed crevice structures on liquid channel walls. The standing air bubbles originate in these crevice structures, and the size adjustment of the air bubble can be used to realise the alignment of the hydraulic resistance. The presented pneumatic damping method is not only low-cost and practical but can also be used in elastomeric and rigid micro-channels without complex microstructure.