A bidirectional Knudsen pump with superior thermal management for micro-gas chromatography applications

Bidirectional gas flow is needed for many microsystems, in particular gas chromatographs. This paper reports a bidirectional Knudsen pump (KP) with superior thermal management. Without moving parts, the KP is reliable, silent, and scalable. However, a bidirectional KP requires controlled heat dissipation that matches the pumping need in each direction. This work integrates a micromachined KP chip that has an effective pumping area of 16×16 mm
²
, with two customized planar heat sinks with prescribed heat dissipation. This KP produces a maximum air flow rate of ≈0.82 sccm and a maximum blocking pressure of ≈880 Pa at 2 W. The overall bidirectional performance is improved by 2X-3X compared to prior work, as a consequence of effective thermal management.