Abstract: Embodiments of the present invention relate to a microfluidic flow restrictor having a converging tapered inlet connected by a constant internal diameter section to a diverging tapered outlet having an outlet face and a smooth and gradual transition from the constant internal diameter section to the outlet face. This dual tapered capillary flow restrictor may be incorporated into a system such as a microfluidic circuit. Using a dual tapered capillary for accurate flow control together with a constant pressure source provides a more steady flow with reduced flow fluctuation caused by bubbles passing or pinning to the capillary end-face. Further, when connected in series, these dual tapered capillary flow restrictors may reduce noise in flow and pressure measurements, reduce bubble segmentation, and reduce bubble pinning.

Abstract: Embodiments of the present invention relate to a microfluidic flow restrictor having a converging tapered inlet connected by a constant internal diameter section to a diverging tapered outlet having an outlet face and a smooth and gradual transition from the constant internal diameter section to the outlet face. This dual tapered capillary flow restrictor may be incorporated into a system such as a microfluidic circuit. Using a dual tapered capillary for accurate flow control together with a constant pressure source provides a more steady flow with reduced flow fluctuation caused by bubbles passing or pinning to the capillary end-face. Further, when connected in series, these dual tapered capillary flow restrictors may reduce noise in flow and pressure measurements, reduce bubble segmentation, and reduce bubble pinning.